Substrate holder and plating apparatus

Description of equivalent WO 2004001813 A2

DESCRIPTION

SUBSTRATE HOLDER AND PLATING APPARATUS

0003Technical Field The present invention relates to a substrate holder for use in a plating apparatus for plating a to-be-plated surface of a substrate, especially a plating apparatus for forming a plated film in fine interconnect trenches or holes, or resist openings provided in the surface of a semiconductor wafer, or for forming bumps (protruding electrodes), which are to be electrically connected to electrodes, etc. of a package, on the surface of a semiconductor wafer, and also to a plating apparatus provided with the substrate holder.

0004Background Art

0005Inatape automatedbonding (TAB) orflipchip, forexample, it has been widely conducted to deposit gold, copper, solder, nickel or multi-layered materials thereof at prescribed areas

0006(electrodes) on the surface of a semiconductor chip having interconnects, thereby forming protruding connecting electrodes (bumps) . Such bumps electrically connect the semiconductor chip with package electrodes or TAB electrodes. There are various methods for forming these bumps, including electroplating method, vapor deposition method, printing method, and ball bump method. The electroplating method has become in wide use due to its relatively stable performance and capability of forming fine connections, inview of the recent tendency to increasing number of I/O terminals on semiconductor chips and to finer pitch. The electroplating method includes a spurting or cup method in which a substrate such as a semiconductor wafer is positionedhorizontallywith the processing surface tobe plated facing downward and a plating solution is spurted from below; and a dipping method in which the substrate is placed vertically in a plating tank and immersed in a plating solution, while a plating solution is supplied from the bottom of the plating tank and is allowed to overflow the tank. According to the dipping method of electroplating, bubbles that can adversely affect the quality of the plating are easily removed and the footprint is small . The dippingmethod is therefore considered to be suited for bump plating in which holes to be filling by the plating are relatively large and which requires a fairly long plating time.

0007Conventional electroplating apparatuses, employing the dipping method, are provided with a substrate holder which detachably holds a substrate, such as a semiconductor wafer, with its end and back surfaces sealed while its front surface (to-be-plated surface) exposed. Such conventional apparatuses carry out plating of the surface of the substrate by dipping the substrate holder, together with the substrate held by it, in a plating solution, and have the advantage of easy release of gas bubbles. Since a substrate holder with a substrate held is dipped in a plating solution, the substrate holder is required to securely seal a peripheral portion of the substrate so that the plating solution will not intrude into the back surface

0008(non-plating surface) side. Accordingly, in a substrate holder which detachably holds a substrate between a pair of supports (holding members) , for example, a sealing member is mounted to one support and the sealing member is brought into pressure contact with a peripheral portion of the substrate placed and heldonthe other support, thereby sealingtheperipheralportion of the substrate.

0009With reference to such a conventional substrate holder, attempts have been made to avoid a leak of a plating solution or other liquid, as by optimization of the shape, fixing method, etc. of sealing member, periodical (including per substrate) cleaning of sealingmember, periodical change of sealingmember, improvement of precision in pretreatments of substrate (formation of a seed layer or a photo resist film) , or minimization of error in setting of a substrate in the substrate holder as well as periodical realignment.

0010Due to deterioration of sealing member, etc., however, it is difficult to effect a complete sealing. Complete sealing is difficult especially in carrying out plating to embed a plated film into fine recesses, since a plating solution having a good permeability is generally used in such a plating so that the plating solution can easily and fully permeate into the fine recesses. On the other hand, it is also generally difficult to detect a leak of plating solution or other liquid. Once a leak of plating solution occurs, the plating solution, which has leaked into a substrate holder, adheres to the back surface of a substrate, and the plating solution adhering to the substrate will transfer to a substrate transport device, resulting in staining of the entire apparatus with the plating solution. In addition, the leaked plating solution can corrode an electrical contact, preventing feeding of electricity.

0011When carrying out electroplating of a substrate held by a substrate holder, it is necessary to electrically connect the substrate to the negative pole of a power source. Accordingly, positioned e.g. inside a sealing member and in a region sealed with the sealing member, there is provided an electrical contact for electrically connecting the substrate to an external wire extending from a power source.

0012A known such electrical contact includes a metal contact plate of e.g. stainless steal having a horseshoe-shape cross-section, and a coil spring for biasing the metal contact plate toward a substrate. When the substrate is held by the substrate holder, one leg of the metal contact plate positioned on the outer side contacts an external wire through the elastic force of the coil spring, while the other leg of the metal contact plate positioned on the inner side contacts the substrate. With a substrate holderhaving such an electrical contact, since the metal contact plate constituting the electrical contact is generally of a rigid body, the contact plate makes a point contact with a substrate, and therefore, poor contact is likely to occur. Further, the metal contact plate contacts the substrate at a position somewhat inside the periphery of the substrate, which narrows an effective area .for pattern formation in the substrate.

0013In addition, substrates and members generally vary in size. Due to the size variation and also to the positional relationship between a pair of supports, etc., positioning (centering) of a substrate tobe heldbythe supports with respect to a sealing member mounted to one of the supports is generally difficult. A separate provision of a special member for the positioning of substrate leads to a large-sized and complicated substrate holder. Furthermore, according to the conventional substrate holder, a sealing member is mounted to one of a pair of supports and the sealing member is brought into pressure contact with a peripheral portion of a substrate placed and held on the other support, thereby sealing the peripheral portion of the substrate, as described above. There is, therefore, a case where when opening the support, to which the sealing member is mounted, to take the substrate out of the substrate holder after completion of plating, the support opens with the substrate sticking to the sealing member and the substrate falls from the support. Measures must therefore be taken to solve the problem. Disclosure of Invention

0014The present invention has been made in view of the above situation in the prior art. It is therefore a first object of the present invention to provide a substrate holder which can effect a more complete sealing with a sealing member and makes it possible to take a substrate out of it easily and securely, and also a plating apparatus provided with the substrate holder . It is a second object of the present invention to provide a substrate holder which can broaden an effective area for pattern formation in a substrate, can easily effect centering of the substrate upon holding of the substrate, and makes it possible to take the substrate out of it easily and securely, and also a plating apparatus provided with the substrate holder .

0015Inorder to achieve the above object, the present invention provides a substrate holder, comprising: a fixed holding member and a movable holding member for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and a suction pad for attracting a back surface of the substrate held between the fixed holding member and the movable holding member.

0016Since the back surface of the substrate is kept attracted to the suction pad, when the movable holding member is moved after plating to release the holding of the substrate and take the substrate out of the substrate holder, the substrate can be prevented from sticking to the sealing member and moving along with the sealing member. Further, since the substrate is thus prevented from being brought upward, when carrying out an automatic operation using an automatic transport device, the substrate can be taken out of the substrate holder stably. The suction pad preferably includes a cup portion of a flexible material, the inside space of the cup portion defining a decompression portion, and attracts the substrate by a suction force which is produced when the substrate presses the opening of the cupportion and forces air out of the decompressionportion to thereby reduce the pressure in the decompression portion. The suction pad is a so-called suction cup. The attraction force of the suction pad is set at such a degree that when taking the substrate out of the substrate holder, the substrate canbe movedhorizontally away fromthe cup portion so that the vacuum can be broken, the substrate can be easily separated from the sealing member, and the substrate can be transferred to a transport robot. Thus, the suction pad has a strong adhesion to the substrate in the vertical direction, and therefore is effective for holding of the substrate, while it allows the substrate to move horizontally and detach from it easily. In the case where the movable member is designed to be openable and closable via a hinge, it is preferred to locate the suction pad on the opposite side of the center of the substrate, held between the fixed holding member and the movable holding member, from the hinge and at a position corresponding to a peripheral portion of the substrate. The suctionpad at such a locationprevents , when opening the movable holding member via the hinge, that peripheral portion of the substrate from sticking to the sealing member and being brought up, which portion would otherwise be first brought up, and can effectively separate the substrate from the sealing member.

0017The suction padmay be connected to a vacuum, and attracts the substrate by vacuuming through the vacuum line . This makes it possible to attract the substrate to the suction pad and hold the substrate on it easily and securely. The holding of the substrate can be released by stopping the vacuuming.

0018The present invention provides another substrate holder, comprising: a fixed holding member and a movable holding member for holding a substrate therebetween; and a sealing member, mounted to the movable holding member, for making pressure contact with a peripheral portion of the substrate to seal the peripheral portion; wherein the sealing member is held integrally by a holding member.

0019Since the sealing member is thus integrally mounted to the holding member, when the movable holding member is moved after plating to release the holding of the substrate and the substrate is taken out of the substrate holder, the sealing portion of the sealing member can be prevented from adhering to the substrate, and the sealing member can be prevented from being torn off from the holding member. Releasability of the sealing member from the substrate can thus be improved.

0020It is preferred to use as the sealing member a multi-seal structure comprising at least two loop-shaped portions. By sealing a peripheral portion of the substrate with the sealing member comprised of the multi-seal structure, the sealing width is substantially widened, so that a more complete sealing can be attained even when the centering of the substrate is not perfect .

0021The multi-seal structure preferably includes partition sealing portions extending in the width direction and provided at certain locations along the circumferential direction. By sealing the certain portions along the circumferential direction of the sealing member with the partition sealing portions in the width direction, it becomes possible tomaintain the sealing ability of the sealingmember evenwhen it is damaged. The present invention provides yet another substrate holder, comprising: a fixed holdingmember and a movable holding member forholdinga substrate therebetween; anda sealingmember, mounted to the movable holding member, for sealing between the movable holding member and the fixed holding member; wherein the sealing member has a W-shaped cross-section, easily collapses when pressed in the width direction, and recovers by its own elastic force when the pressing force is released.

0022The use of such a sealingmember can facilitate its insert into a seal groove, e.g. in a dovetail shape, and prevent it from falling from the seal groove securely. Further in this connection, there is a cut-away portion formed in the movable holding member, which portion is necessary for takeout of a tool upon formation of the dovetail-shaped seal groove. There is, therefore, a fear that a plating solution would intrude from the cut-away portion into the seal groove and, due to denaturing or solidification of the plating solution, the sealing ability of the sealing member would be lowered. In this regard, accordingto the substrate holder ofthis embodiment, the side surfaces of the sealing member are in contact with the sidewall surfaces of the seal groove with a certain elastic force . This prevents the above-described intrusion of plating solution, ensuring the sealing and enhancing the durability of the sealing member.

0023The present invention provides yet another substrate holder, comprising: a fixed holdingmember and amovable holding member for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and a plate-shaped spring member for biasing the substrate toward the fixed holding member when releasing the holding of the substrate between the movable holding member and the fixed holding member.

0024By the use of the spring member, when the movable member is moved after plating to release the holding of the substrate and take the substrate out of the substrate holder, movement of the substrate is restricted and the sealing member mounted to the movable holding member is detached from the substrate, whereby the substrate can be prevented from sticking to the sealing member and moving along with the sealing member.

0025The spring member is preferably a laminated leaf spring comprising a laminate of two or more leaf spring-shaped plates . Such a laminated leaf spring member can secure a long stroke without a plastic deformation and can be set in a considerably small space.

0026The present invention provides yet another substrate holder, comprising: a fixed holdingmember and a movable holding member for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and a leaf spring member for making an elastic contact with a peripheral portion of the substrate when the substrate is held between the movable holdingmember and the fixed holding member.

0027Since the substrate is biased inwardly by the elastic force of the leaf spring member, positioning (centering) of the substrate relative to the substrate holder upon holding of the substrate by the substrate holder can be effected by the leaf spring member.

0028The movable holding member preferably has a function of positioning the substrate with respect to the sealing member. Preferably, the leaf spring member also serves as an electrical contact that contacts the substrate to feed electricity to the substrate. This eliminates the need to separately provide the electrical contact, thus simplifying the structure of the substrate holder.

0029The movable holding member preferably has a function of positioning the substrate with respect to the sealing member and the electrical contact.

0030By thus providing the movable holding member with the substrate-sealing member and preferably the electrical contact for feeding electricity to the substrate, and also the centering function for the substrate, it becomes possible to previously make the center of the movable holding member coincide with the centerofthe substrate-sealingmember (andofthe electrical contact) and, when the movable holding member engages the fixed holding member on which the substrate is placed, shift the substrate by the substrate-centering function of the movable holding member to a position where the center of the substrate coincides with the center of the movable holding member . Thus , the center of the substrate can be made to coincide with the center of the substrate-sealing member (and of the electrical contact for feeding electricity to the substrate) automatically upon engagement between the movable holdingmember and the fixed holding member.

0031In these days, the effective area of substrate is shifting toward the outer side and the so-called edge exclusion region of substrate is becoming extremelynarrow. In such a situation, the above substrate holder makes it possible to securely effect sealing of a substrate and electric feeding to the substrate in the narrow region of the substrate. The present invention provides yet another substrate holder, comprising: a fixed holding member and a movable holding member for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and at least one pair of conductors for detecting a liquid leak, which is provided in the fixed holding member and which, when a plating solution leaks to the back surface side of the substrate held between the movable holding member and the fixed holding member, short-circuits via the leaked plating solution, When a liquid leak occurs and the pair of conductors short-circuits via a plating solution, an electric current begins to flow between the pair of conductors and the electric resistance changes (becomes not infinite) . Accordingly, the occurrence of liquid leak can be detected quickly and securely by the simple measurement of the electric resistance.

0032The pair of conductors is preferably provided at a lower portion of the fixed holding member where the leaked plating solution piles up. By utilizing the fact that upon a leak of plating solution, the leaked plating solution piles up at a lower portion of the fixed holding member, and thus disposing the conductors at such a local location, a liquid leak can be detected over the whole area of the substrate . The pair of conductors may be disposed in a loop shape and positioned inside the sealing member when the substrate is held between the movable holding member and the fixed holding member .

0033The invention provides yet another substrate holder, comprising: a fixed holding member and a movable holding member for holding a substrate therebetween; an inner sealing member for making pressure contact with a peripheral portion of the substrate to seal the peripheral portion; and an outer sealing member, disposed around the substrate, for sealing between the fixed holding member and the movable holding member.

0034By thus providing the two sealing members, i.e. the inner sealingmember andthe outer sealingmember, to separatelyeffect sealing of a peripheral portion of the substrate with the inner sealing member and sealing between the movable holding member and the fixed holding member with the outer sealing member, an improved sealing can be effected.

0035Preferably, the inner sealingmember and the outer sealing member are mounted to the movable sealing member.

0036Preferably, a step is provided in an outer peripheral portion of the movable holding member and a press ring is rotatably mounted fitly to the step, and the movable holding member is pressed via the press ring against the fixed holding member to hold the substrate.

0037Preferably, the fixed holding member is provided with a clamper for restricting movement of the press ring away from the fixed holding member.

0038By thus restricting movement of the press ring, rotatably mounted fitly to the step providedin an outer peripheral portion of the movable holdingmember, away fromthe fixed holdingmember by the clamper provided in the fixed holding portion, it becomes possible to shorten the distance between the forefront of the substrate holder and the substrate surface held by the substrate holder, whereby a stirrer (paddle) may be disposed closer to the substrate surface to thereby improve the flow of plating solution over the surface of the substrate.

0039The present invention provides a plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising: a fixed holding member and a movable holding member for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and a suction pad for attracting a back surface of the substrate held between the fixed holding member and the movable holding member.

0040The present inventionprovides another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising: a fixed holding member and a movable holding member for holding a substrate therebetween; and a sealing member, mounted to the movable holding member, for making pressure contact with a peripheral portion of the substrate to seal the peripheral portion; wherein the sealing member is held integrally by a holding member.

0041The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising : a fixed holding member and a movable holding member for holding a substrate therebetween; and a sealing member, mounted to the movable holding member, for sealing between the movable holding member and the fixed holding member; wherein the sealing member has a W-shaped cross-section, easily collapses when pressed in the width direction, and recovers by its own elastic force when the pressing force is released. The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising : a fixed holding member and a movable holding member for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and a plate-shaped spring member for biasing the substrate toward the fixed holding member when releasing the holding of the substrate between the movable holding member and the fixed holding member.

0042The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising: a fixed holding member and a movable holdingmember for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and a leaf spring member for making an elastic contact with a peripheral portion of the substrate when the substrate is held between the movable holdingmember and the fixed holdingmember.

0043The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising: a fixed holding member and a movable holdingmember for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and at least one pair of conductors for detecting a liquid leak, which is provided in the fixed holding member and which, when aplating solutionleaks to the back surface side of the substrate held between the movable holding member and the fixed holding member, short-circuits via the leaked plating solution. The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising: a fixed holding member and a movable holding member for holding a substrate therebetween; an inner sealing member for making pressure contact with a peripheral portion of the substrate to seal the peripheral portion; and an outer sealing member, disposed around the substrate, for sealing between the fixed holding member and the movable holding member. The present invention provides yet another substrate holder, comprising: a fixedholdingmember andamoveable holding member forholdinga substrate therebetween; anda sealingmember for sealing an outer circumferential end of the substrate when the substrate is held between the movable holding member and the fixed holding member; wherein the fixed holding member has a conductor, and the moveable holding member has an electrical contact in the formof a leaf springmember for being electrically connected to the conductor in the area sealed by the sealing member to supply the substrate with electric energy when the substrate is held between the movable holding member and the fixed holding member.

0044By thus forming electrical contact in a leaf spring shape and allowing the electrical contact to make contact with the substrate through the elastic force of the electrical contact per se, it becomes possible to reduce poor electrical contact. Further, since the contactportion contacts aperipheral portion, outer than the sealing portion, of the substrate, an effective area for pattern formation in the substrate can be broadened. The electrical contact is preferably adapted to make an elastic contact with a surface of the substrate when the substrate is held between the movable holding member and the fixed holding member. The electrical contact is preferably adapted to make an elastic contact with an outer circumferential edge of the substrate when the substrate is held between the movable holding member and the fixed holding member.

0045Since the substrate is biased inwardly by the elastic force of the contactportion of the leaf spring-shapedelectrical contact, positioning (centering) of the substrate relative to the substrate holder upon holding of the substrate by the substrate holder can be effected by the electrical contact. Further, byprovidingthemovable holdingmemberwith the sealing member and the electrical contact, and effecting the positioning

0046(centering) of the substrate relative to the substrate holder by the electrical contact, it becomes possible to make the positional relationship between the substrate, the sealing member and the electrical contact always constant when the substrate is held by the substrate holder.

0047Preferably, the electrical contact has a tip for contacting the substrate, said tip being divided into at least two segments or comprising parallel segments disposed in respective adjacent positions. With this arrangement, even if dirt or the like is attached to the contact portions of some of the electrical contacts, the other electrical contacts are kept in electrical connection to the substrate.

0048The divided segments or the parallel segments may have portions for contacting the substrate, said portions being staggered in a radial direction of the substrate. With this arrangement, even if the substrate suffers a slight positioning error, at least some of the electrical contacts are brought into contact with the substrate. The present invention provides yet another substrate holder, comprising: a fixedholdingmember and amovable holding member forholding a substrate therebetween; anda sealingmember mounted to the fixed holding member or the movable holding member; wherein the fixedholdingmember and the movable holding member have respective tapered portions for engaging each other and positioning the fixed holdingmember and the movable holding member in central alignment with each other when the substrate is held between the movable holding member and the fixed holding member.

0049By thus providing the fixed holdingmember and the movable holding member with the tapered portions, positioning of the members with respect to the center can be effected automatically throughthe engagementbetweenthe taperedportions inthe course of holding the substrate by the members, if the members are not correctly positioned when they are away from each other.

0050The tapered portion of the movable holding member is preferably adapted to guide an outer circumferential edge of the substrate to position the substrate when the substrate is held between the movable holding member and the fixed holding member .

0051This is makes it possible to position of the fixed holding member and the movable holding member with respect to the center and position (center) of the substrate with respect to the substrate holder simultaneously in the course of holding the substrate by the members.

0052The present invention provides yet another substrate holder, comprising: a fixed holdingmember and a movable holding member for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and a springy leaf spring member, mounted to the fixed holding member, which has a free end positioned inwardly of an outer circumferential portion of the substrate when the substrate is held between the movable holding member and the fixed holding member, and positioned outwardly of the outer circumferential portion of the substrate when the holding of the substrate between the movable holding member and the fixed holding member is released.

0053Since the movement of the substrate is restricted by the free end of the leaf spring member positioned inwardly of an outer circumferential portion of the substrate, when themovable holding member is moved after plating to release the holding of the substrate and take the substrate out of the substrate holder, the substrate can be prevented from sticking to the sealing member and moving along with the sealing member. With the movement of the substrate, the free end of the leaf spring member is positioned outwardly of the outer circumferential portion of the substrate, whereby the processed substrate is not prevented from being taken out of the substrate holder by the leaf spring member, and a substrate to be processed is not preventedby the leaf springmember frombeinginserted in place .

0054The free endof the leaf springmemberis preferablyadapted to make an elastic contact with a surface of the substrate when the substrate is held between the movable holding member and the fixed holding member.

0055The free endofthe leaf springmember is preferablyadapted to make an elastic contact with an outer circumferential edge of the substrate when the substrate is held between the movable holding member and the fixed holding member. Since the substrate is biased inwardly by the elastic force of the leaf spring member, positioning (centering) of the substrate relative to the substrate holder upon holding of the substrate by the substrate holder canbe effectedby the leaf springmember.

0056Preferably, the leaf spring member also serves as electrical contact for supplying the substrate with electric energy when the substrate is held between the movable holding member and the fixed holding member. With this arrangement, it is not necessary to provide dedicated leaf spring member for the sole purpose of separating the substrate fromthe sealing member when the substrate holder releases the substrate, and hence the substrate holder can be simplified in structure. The present invention provides yet another substrate holder, comprising: a fixedholdingmember andamoveableholding member for holding a substrate therebetween; a sealing member for sealing an outer circumferential end of the substrate when the substrate is held between the movable holding member and the fixed holding member; and a springy leaf spring member for making an elastic contact with an outer circumferential edge of the substrate in the area sealed by the sealing member to position the substrate when the substrate is held between the movable holding member and the fixed holding member.

0057Since the substrate is biased inwardly by the elastic force of the springyleaf springmember, positioning (centering) of the substrate relative to the substrate holder upon holding of the substrate by the substrate holder can be effected by the leaf spring member. Further, by providing the movable holdingmemberwiththe sealingmember andthe electrical contact, and effecting the positioning (centering) of the substrate relative to the substrate holder by the electrical contact, it becomes possible to make the positional relationship between the substrate, the sealing member and the electrical contact always constant when the substrate is held by the substrate holder.

0058It is preferred that the movable holding member further comprises an electrical contact for making an elastic contact with the substrate to supply the substrate with electric energy when the substrate is held between the movable holding member and the fixed holding member.

0059The present invention provides yet another substrate holder, comprising: a fixedholdingmember and amoveable holding member forholding a substrate therebetween; anda sealingmember for sealing an outer circumferential end of the substrate when the substrate is held between the movable holding member and the fixed holding member; wherein the sealing member has lips for contacting a peripheral portion of the substrate and a surface of the fixed holding member, respectively, when the substrate is held between the movable holding member and the fixed holding member, and is integrally held by a support body which is mounted in a place between the lips.

0060Since the sealing member is thus integrally held by a support body, when the movable holding member is moved after plating to release the holding of the substrate and the substrate is taken out of the substrate holder, the sealing portion of the sealing member can be prevented from adhering to the substrate, and the sealing member can be prevented from being torn off from the holding member . Releasability of the sealing member from the substrate can thus be improved.

0061The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising: a fixed holdingmember and a moveable holding member for holding a substrate therebetween; and a sealing member for sealing an outer circumferential end of the substrate when the substrate is held between the movable holding member and the fixed holding member; wherein the fixed holding member has a conductor, and the moveable holding member has an electrical contact in the formof a leaf springmember for being electrically connected to the conductor in the area sealed by the sealing member to supply the substrate with electric energy when the substrate is held between the movable holding member and the fixed holding member. The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising : a fixed holding member and a movable holding member for holding a substrate therebetween; and a sealing member mounted to the fixed holding member or the movable holding member; wherein the fixedholdingmember and the movable holding member have respective taperedportions for engaging each other and positioning the fixedholdingmember and the movable holding member in central alignment with each other when the substrate is held between the movable holding member and the fixed holding member.

0062The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising: a fixed holding member and a movable holding member for holding a substrate therebetween; a sealing member mounted to the fixed holding member or the movable holding member; and a springy leaf springmember, mounted to the fixedholdingmember, which has a free end positioned inwardly of an outer circumferential portion of the substrate when the substrate is held between the movable holding member and the fixed holding member, and positioned outwardly of the outer circumferential portion of the substrate when the holding of the substrate between the movable holding member and the fixed holding member is released.

0063The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising: a fixedholdingmember and amoveable holdingmember for holding a substrate therebetween; a sealing member for sealing an outer circumferential end of the substrate when the substrate is held between the movable holding member and the fixedholdingmember; and a springyleaf spring ember formaking an elastic contact with an outer circumferential edge of the substrate in the area sealed by the sealing member to position the substrate when the substrate is held between the movable holding member and the fixed holding member.

0064The present invention provides yet another plating apparatus comprises a substrate holder for holding a substrate and to be transported with the substrate held and immersed in a plating solution in a plating tank, said substrate holder comprising : a fixed holdingmember and a moveable holding member for holding a substrate therebetween; and a sealingmember for sealing an outer circumferential end of the substrate when the substrate is held between the movable holding member and the fixed holding member; wherein the sealing member has lips for contacting a peripheral portion of the substrate and a surface of the fixed holding member, respectively, when the substrate is held between the movable holdingmember and the fixed holding member, and is integrally held by a support body which is mounted in a place between the lips.

0065The above and other objects, features, and advantages of the present invention will be apparent from the following description when taken in conjunction with the accompanying drawings which illustrates preferred embodiments of the present invention by way of example.

0066Brief Description of Drawings FIG. 1 is a layout plan of a plating apparatus provided with a substrate holder according to an embodiment of the present invention;

0067FIG. 2 is a plan view of the substrate holder shown in FIG. 1;

0068FIG. 3 is a sectional right side view of the substrate holder shown in FIG. 1;

0069FIG.4 is a vertical sectional front view of the substrate holder shown in FIG. 1;

0070FIGS. 5A through 5C are diagrams illustrating the relationship between a conductor, an electrical contact and a substrate in the course of holding of the substrate by the substrate holder shown in FIG. 1; FIGS. 6A through 6C are diagrams illustrating the relationship between a tapered portion of a fixed holdingmember and a tapered portion of a movable holding member in the course of holding of a substrate by the substrate holder shown in FIG. 1; FIG. 7 is a cross-sectional view of a portion of the substrate holder shown in FIG. 1 in which a suction pad is provided;

0071FIG. 8 is a cross-sectional view showing the state of the substrate holder when it is locked by a locking/unlocking mechanism;

0072FIG .9 is a plan view of the locking/unlocking mechanism;

0073FIGS. 10A through 10C are diagrams illustrating the relationship between a leaf spring member and a substrate in the course of holding of the substrate by the substrate holder; FIG. 11 is a cross-sectional view of a laminated leaf spring as a leaf spring member;

0074FIG. 12 is a plan view of another inner sealing member; FIGS. 13A and 13B are enlarged views of the portion A of FIG. 12; FIG. 14 is a transverse sectional view of FIG. 12;

0075FIG. 15 is a plan view of a substrate holder according to another embodiment of the present invention;

0076FIG. 16 is a plan view of a substrate holder according to yet another embodiment of the present invention;

0077FIG. 17 is a plan view of a substrate holder according to yet another embodiment of the present invention;

0078FIG.18 is a vertical sectional front view of the substrate holder shown in FIG. 17;

0079FIG. 19 is a sectional right side view of the substrate holder shown in FIG. 17;

0080FIG.20A is a cross-sectional view showing the conductor and the electrical contact of the substrate holder shown in FIG. 17 before holding of a substrate;

0081FIG.20B is a cross-sectional view showing the conductor and the electrical contact of the substrate holder shown in FIG. 17 after holding of a substrate;

0082FIG. 21A is a cross-sectional view showing the tapered portions of the fixed holding member and the movable holding member of the substrate holder before holding of a substrate;

0083FIG. 21B is a cross-sectional view showing the tapered portions of the fixed holding member and the movable holding member of the substrate holder after holding of a substrate; FIGS. 22A through 22F are diagrams illustrating, in sequence steps, the relationship between a leaf spring member and a member that engages the leaf spring member to deform the leaf spring member;

0084FIG.23A is a cross-sectional view of another electrical contact before holding of a substrate;

0085FIG.23B is a cross-sectional view of another electrical contact after holding of a substrate;

0086FIGS. 24A through 24F are diagrams illustrating, in a sequence steps, the relationship between an electrical contact/leaf spring member, serving both as an electrical contact and as a leaf spring member, and a member that engages the electrical contact/leaf spring member to deform the electrical contact/leaf spring member; FIG.25A is a cross-sectional view of a leaf spring member that effects positioning of a substrate before holding of the substrate;

0087FIG.25B is a cross-sectional view of a leaf spring member that effects positioning of a substrate after holding of the substrate;

0088FIGS. 26A through 26D are plan views showing different electrical contacts, respectively; and

0089FIGS. 27A through 27D are diagrams illustrating, in a sequence of process steps, the formation of bumps (protruding electrodes) on a substrate.

0090Best Mode for Carrying Out the Invention

0091Preferred embodiments of the present invention will now be described with reference to the drawings.

0092FIG.1 shows a layout plan of a plating apparatus provided with a substrate holder according to an embodiment of the present invention. As shown in Fig.1, the plating apparatus includes two cassette tables 12 each for placing thereon a cassette 10 forhousing substratesW suchas semiconductorwafers, analigner 14 for aligning the position of an orientation flat or a notch of the substrate W in a predetermined direction, and a spin drier 16 for rotating the substrate W after plating at a high speed to dry the substrate. Further, a substrate attaching/detaching section 20 for placing thereon a substrate holder 18 for detachably holding the substrate W, and attaching/detaching the substrate W to/from the substrate holder 18, is provided near the spin drier 16. Furthermore, a substrate transfer device 22, comprised of a transfer robot, is disposed in the center of the above units for transferring the substrate W between the units.

0093The plating apparatus also includes, disposed in order from the substrate attaching/detaching section 20 side, a stocker 24 for stocking and temporary housing the substrate holder 18, a pre-wetting tank 26 for immersing the substrate W in pure water, a presoaking tank 28 for etching away an oxide film on a seed layer 500 (see FIGS. 27A to 27C) formed on the surface of the substrate W, a first water-washing tank 30a for washing the surface of the substrate W with pure water, a blow tank 32 for draining (drying) the substrate W after washing, a second water-washing tank 30b, and a plating tank 34. The plating tank 34 houses a plurality of copper plating units 38 in an overflow tank 36. Each copper plating unit 38 houses one substrate W to carry out copper plating of the substrate. Though copper plating is carried out in this embodiment, the plating apparatus is of course applicable to other types of plating, such as nickel, solder, silver and gold plating. Further, positioned on one side of the above devices and tanks, there is provided a substrate holder transport device 40, which employs e.g. a linear motor system, for transporting the substrate holder 18 together with the substrate W between the devices and tanks. The substrate holder transport device 40 includes a first transporter 42 fortransportingthe substrate W between the substrate attaching/detaching section 20 and the stocker 24, and a second transporter 44 for transporting the substrate W between the stocker 24, the pre-wetting tank 26, the presoaking tank 28, the water-washing tanks 30a, 30b, the blow tank 32 and the plating tank 34. In this regard, it is possible to provide only the first transporter 42 without providing the second transporter 44.

0094On the opposite side of the overflow tank 36 from the substrate transport device 40 are disposed paddle drive devices 46 for driving a paddle (not shown) provided in each copper plating unit 38 as a stirrer for stirring a plating solution.

0095The substrate attaching/detaching section 20 includes a tabular loading plate 52 which is slidable laterally along rails 50. Two substrate holders 18 are placed horizontally and in parallel on the loading plate 52. After one substrate W is transferred between one substrate holder 18 and the substrate transfer device 22, the loading plate 52 is slid laterally so that the other substrate is transferred between the other substrate holder 18 and the substrate transfer device 22.

0096As shown in FIGS. 2 through 7, the substrate holder 18 includes a rectangular tabular fixed holding member 54 made of, for example, a vinyl chloride resin, and a movable holding member 58 mounted openably and closably via a hinge 56 on the fixed holding member 54. Though in this embodiment the movable holding member 58 is designed to be openable and closable by the hinge 56, it is also possible, for example, to dispose the movable holdingmember 58 opposite to the fixed holding member 54, and open and close the movable holding member 58 by moving it to and away from the fixed holding member 54.

0097The movable holding member 58 includes a base portion 58a and a support portion 58b which has a ring shape according to this embodiment. The movable holding member 58 is made of, for example, a vinyl chloride resin so that it has a good slippage with the below-described press ring 60. On the far side surface of the support portion 58b from the fixed holding member 54 is mounted bybolts 64 (see FIGS.6Ato6C) an inwardly protruding sealing member (hereinafter referred to as "inner sealing member") 62 for contacting a peripheral portion of the substrate W to seal the portion. On the other hand, a dovetail-shaped seal groove 66 is formed in the surface of the support portion 58b on the holding member 54 side, and a sealing member (hereinafter referred to as "outer sealing member") 68 for sealing the fixed holding member 54 and the movable holding member 58 is fitted into the seal groove 66.

0098The inner sealing member 62 is to make pressure contact with a peripheral portion of the surface (to-be-plated surface) of the substrate W when it is held by the substrate holder 18, thereby sealing that portion, and has at its inner periphery a steeple-shaped sealingportion 62a which protrudes downwardly and makes a linear contact with the peripheral portion of the substrate W. The inner sealing ember 62 is mounted integrally on a holding member 70, made of e.g. titanium, which holds the sealing member 62. In particular, the inner sealing member 62 is attached to the holding member 70 such that the sealing member 62 covers almost the whole surface of the holdingmember 70, thereby preventing the sealing member 62 from peeling or falling from the holding member 70.

0099Since the inner sealing member 62 is thus integrally mounted on the holdingmember 70, when the movable holdingmember 58 is moved after plating to release the holding of the substrate W and the substrate W is taken out of the substrate holder 18, the sealing portion 62a of the inner sealing member 62 can be prevented from adhering to the substrate W, and hence the inner sealing member 62 can be prevented from being torn off from the holding member 70. Releasability of the sealing member 62 from the substrate W can thus be improved. Further, since the inner sealing member 62 makes a linear contact with the substrate W, sealing can be effected securely at a low clamping pressure and, in addition, an effective area for pattern formation in the substrate W can be broaden.

0100The inner sealing member 62, mounted integrally to the holding member70, is mounted by bolts 64 to the support portion 58b of the movable holding member 58. A ring-shaped sealing member 71 is interposed between the inner sealing member 62 and the support portion 58b. The bolts 64 are disposed outside of the sealing member 71, and the inner sealing member 62 is fixed to the support portion 58b by fastening the bolts 64 to squash the sealing member 71. This prevents a leak of water from the interstice between the inner sealing member 62 and the holding portion 58b, shown by the arrow in FIG. 6A, or from the portions where the bolts 64 are fixed.

0101The outer sealing member 68, on the other hand, is to make pressure contact with the movable holding member 58 side surface of the fixedholdingmember 54 to seal the contact portion when the substrate W is held by the substrate holder 18.

0102According to this embodiment, the outer sealing member 68 has a W-shaped cross-section, has sealing portions 68a, 68b in the lower and upper surfaces at almost the center in the width direction, and broadens toward the bottom of the seal groove

010366. When the broad portion of the outer sealing member 68 is pressed in the width direction, the portion easily collapses and narrows. Upon release of the pressing force, the portion recovers by the elastic force. When fitting the outer sealing member 68 into the dovetail-shaped seal groove 66, the broad portion of the outer sealing member 68 is collapsed in the width direction, thereby facilitating insert of the outer sealing member 68 into the seal groove 66. After the insert, the outer sealing member 68 expands by the elastic force, whereby the sealingmember canbe prevented from falling fromthe seal groove

010466.

0105As shown in FIG.7, there is a cut-away portion 66a formed in the movable holding member 58 which is necessary for takeout of a tool upon formation of the dovetail-shaped seal groove 66. There is, therefore, a fear that a plating solution would intrude from the cut-away portion 66a into the seal groove 66 and, due to denaturing or solidification of theplating solution, the sealing ability of the outer sealing member 68 would be lowered. In this regard, according to this embodiment, the side surfaces of the outer sealing member 68 are in contact with the sidewall surfaces of the seal groove 66 with a certain elastic force. This presents the above-described intrusion of plating solution, ensuring the sealing and enhancing the durability of the outer sealing member 68.

0106A step is provided in an outer peripheral portion of the movable holdingmember 58, and a press ring 60 is fitly supported unescapably and rotatably to the step by press plates 72. The press ring 60 is made of, for example, titanium that is highly resistant to an oxidizing atmosphere and has a sufficient rigidity.

0107Positioned outside the press ring 60, inversed L-shaped clampers 74, each having an inwardly protruding portion, are mounted vertically on the fixed holding member 54 at regular intervals along the circumferential direction of the fixed holding member 54. The upper surface of each outwardly protruding portion of the press ring 60 and the lower surface of the inwardlyprotruding portion of each clamper 74 are tapered circumferentially in opposite directions. Further, a plurality of long holes 60a (e.g. four holes) are formed in the press ring 60 along the circumferential direction. As will be described below, rotating pins 112 are inserted into the long holes 60a, and the pins 112 are rotated to thereby rotate the press ring 60.

0108When the movable holdingmember 58 is open, the substrate W is inserted into the center of the fixed holding member 54, and then the movable holding member 58 is closed by the hinge 56. The press ring 60 is rotated clockwise so as to slip the outwardly protruding portions of the press ring 60 in under the inwardly protruding portions of the clampers 74. The fixed holding member 54 and the movable holding member 58 are fastened to each other via the tapered surfaces of the press ring 60 and the clampers 74, whereby the movable holding member 58 is locked. The lock is released by rotating the press ring 60 counterclockwise and thereby drawing the outwardly protruding portions of thepress ring 60 fromthe inversedL-shaped clampers 74. When the movable holding member 58 is thus locked, the sealing portion 62a of the inner sealingmember 62 is in pressure contact with the surface of the substrate W, while with respect to the outer sealing member 68, the sealing portion 68a is in pressure contact with the surface of the fixed holding member 54 and the sealing portion 68b is in pressure contact with the bottom surface of the seal groove 66. The sealing members 62, 68 are respectivelyunder a uniformpressure so that a sufficient sealing is ensured. In the center of the fixed holding member 54 is provided anupwardlyprotruding ring-shapedridge 82 withits sizemeeting the size of the substrate W. The upper surface of the ridge 82 serves as a support surface 80 that contacts a peripheral portion of the substrate W and supports the substrate W. Recesses 84 are formed in the ridge 82 at certain locations along the circumferential direction.

0109As shown in FIG. 2 and FIGS. 5A through 5C, a plurality of conductors (electrical contacts) 86 (12 conductors are shown in FIG. 2) are disposed in the recesses 84, which conductors 86 are respectively connected to a plurality of wires extending from external contacts provided in the below-described hands 120. When the substrate W is placed on the support surface 80 of the fixed holding member 54, the end portions of the conductors 86 with spring properties are exposed on the surface of the fixed holding member 54, and are beside the substrate W.

0110On the other hand, the leg portion 88a each of electrical contacts 88 is fixed to the support portion 58b of the movable holding member 58 at a location where it is opposed to each conductor 86. The electrical contact 88 is formed in a leaf spring shape, and has a positioning (centering) function for the substrate W and a function of preventing the substrate W from sticking to the sealing portion 62a of the inner sealing member 62 and being brought up along with the sealing portion 62a when taking the substrate W afterplating out of the substrate holder 18. Thus, the electrical contact 88 has a contactportion 88b positioned below the inner sealing member 62 and protruding inwardly in a leaf spring shape . The contact portion 88b bends easily due to its spring properties and, when the substrate W is held by the fixed holding member 54 and the movable holding member 58, makes an elastic contact with a peripheral portion of the substrate W supported on the support surface 80 of the fixed holding member 54.

0111When the substrate W is placed on the support surface 80 of the fixed holding member 54 as shown in FIG. 5A, and the movable holding member 58 is then moved to the fixed holding member 54 to lock the movable holding member 58 and hold the substrate W as shown in FIGS. 5B and 5C, the exposed portion of the conductor 86, by its elastic force, makes an elastic contact with the lower surface of the leg portion 88a of the electrical contact 88 to thereby make an electrical connection, and the contact portion 88b of the electrical contact 88, by its elastic force, makes an elastic contact with the substrate W. Feeding of electricity to the substrate W via the electrical contacts 88 can thus be effected while the substrate W is held with the substrate holder 18 and sealed with the sealing members 62, 68. By thus forming each electrical contact 88 in a leaf spring shape and allowing the front end of the contact portion 88b of the electrical contact 88 to make contact with the substrate W through the elastic force of the electrical contact 88 per se, it becomes possible to reduce poor electrical contact. Further, since the contact portion 88b contacts a peripheral portion, outer than the sealing portion, of the substrate W, an effective area for pattern formation in the substrate W can be broadened. Further, since the substrate W is biased inwardly by the elastic force of the contact portion 88b of the leaf spring-shaped electrical contact 88, positioning (centering) of the substrate W relative to the substrate holder 18 upon holding of the substrate by the substrate holder 18 can be effected by the electrical contact 88. Furthermore, by providing the movable holding member 58 with the inner sealing member 62 and the electrical contacts 88, and effecting the positioning of the substrate W relative to the substrate holder 18 by the electrical contacts 88, it becomes possible to make the positional relationshipbetween the substrate W, the sealing member 62 and the electrical contacts 88 always constant when the substrate W is held by the substrate holder 18.

0112When taking the substrate W out of the substrate holder 18 after completion of a series of the processing, the movable holding member 58 is moved away from the fixed holding member 54. During the movement, as shown in FIGS.5Cand5B, the contact portion 88b of each electrical contact 88 is in pressure contact with the peripheral portion of the substrate W so that the substrate W is biased downwardly. Movement of the substrate W is thus restrictedby the electrical contacts 88. Accordingly, if the sealing member 62 sticks to the substrate W, only the sealingmember 62 and the movable holdingmember 58 move upward, whereas the substrate W is forcibly detached from the sealing member 62. When the movable holding member 58 further moves upward, the contact portions 88b of the electrical contacts 88 detach from the substrate W, returning to the position shown in FIG. 5A.

0113Thus, when the movable holding member 58 is moved after plating to release the holding of the substrate W and take the substrate W out of the substrate holder 18, the substrate W can be prevented from sticking to the sealing member 62 and moving along with the sealing member 62.

0114With reference to the conductor 86, it is preferred that at least the surface to make contact with the electrical contact 88 have a coating of e.g. gold or platinum plating.

0115As shown in FIGS. 6A to 6C, the ridge 82 of the fixed holding member 54 partly has a tapered portion 82a with a steeple-shaped tapered surface, while the support portion 58b of the movable holdingmember 58 has in its inner circumferential surface a tapered portion 90 to be opposed to the taperedportion 82a and having a reverse tapered surface to the tapered surface of the tapered portion 82a. When the substrate W is held with the fixed holding member 54 and the movable holding member 58, the tapered portion 82a and the tapered portion 90 engage each other to effect positioning of the members 54, 58 with respect to the center. Thus, when the substrate W is placed on the support surface 80 of the fixed holding member 54 as shown in FIG. 6A, and the movable holding member 58 is then moved to the fixed holding member 54 to lock the movable holding member 58 and hold the substrate W as shown in FIGS. 6B and 6C, the taperedportions 82a, 90 serve as a mutual guide for positioning of the movable holding member 58 relative to the fixed holding member 54, or vice versa.

0116By thus providing the ridge 82 of the fixed holding member 54 and the support portion 58b of the movable holding member 58 with the tapered portions 82a, 90, positioning of the members 54, 58 with respect to the center can be effected automatically through the engagement between the tapered portions 82a, 90 in the course of holding the substrate W by the members 54, 58, if the members 54, 58 are not correctly positioned when they are away from each other.

0117As described above, positioning of the fixed holding member 54 and the movable holding member 58 with respect to the center and positioning (centering) of the substrate W with respect to the substrate holder 18, and thus with respect to the inner sealing member 62, can be effected simultaneously in the course of holding the substrate W by the members 54, 58.

0118However, a precise centering can be effected with difficulty only through the engagement between the tapered portions 82a, 90. This is because a clearance, if small, is necessary between the two tapered portions 82a, 90 in order to facilitate the engagement therebetween. Accordingly, the center of the substrate W inevitably deviates from the center of the movable holding member 58 by the clearance. In view of this, the movable holding member 58 is provided with a plurality of leaf springmembers 140, as will be described later . The leaf spring members 140 make an elastic contact with the peripheral edge of the substrate W and evenly apply a pressing force acting to move the substrate W toward the center of the movable member 58. Accordingly, when the movable holding member 58 engages the fixed holding member 54, the substrate W is shifted so that the center of the substrate can coincide exactly with the center of the movable holding member 58. It is of course possible that the plurality of leaf springs take the form of an integral structure that surrounds the periphery of the substrate.

0119Further, the movable holdingmember and the fixed holding member are not necessarily coupled by the hinge, and may of course be separated. As shown in FIG.2, relatively wide recesses 92 are formed in the ridge 82 of the fixed holding member 54 on the far side from the hinge 56 at two locations according to this embodiment . A suction pad 94 is housed in each recess 92. As shown in detail in FIG. 7, the suction pad 94 is made of a flexible material, such as rubber, has a conical cup 96 having a decompression portion inside, and is mounted by a bolt 100 on the fixed holding member 54. When the substrate W is held by the substrate holder 18, the substrate W presses the opening of the cup portion 96 and expands the cup portion 96 outwardly, so that air in the suctionpad 94 is forcedout andthepressure inthe decompression portion is reduced, whereby the back surface of the substrate W is attracted by suction to the suction pad 94. Since the back surface of the substrate W is kept attracted to the suction pad 94, when the movable holding member 58 is moved after plating to release the holding of the substrate W and take the substrate W out of the substrate holder 18, the substrate W can be prevented from sticking to the sealing member 62 and moving along with the sealingmember 62. Further, since the substrate W is thus prevented from being brought upward, when carrying out an automatic operation using an automatic transport device, the substrate W can be taken out of the substrate holder 18 stably. The attraction force of the suction pad 94 is set at such a degree that when taking the substrate W out of the substrate holder 18 in the above-described manner, the substrate W can be moved horizontally away from the cup portion so that the vacuum can be broken, the substrate W can be easily separated fromthe sealingmember 62, and the substrate W can be transferred to the robot. Thus, the suction pad 94 has a strong adhesion to the substrate W in the vertical direction, and therefore is effective for holding of the substrate, while it allows the substrate W to move horizontally and detach from it easily. Though the location and number of the suction pad 94 may be determined arbitrarily, it is preferred to locate the suction pad 94 on the opposite side of the center of the substrate W, held by the substrate holder 18, from the hinge 64 and at a position corresponding a peripheral portion of the substrate W. The suction pad 94 at such a location prevents, when opening the movable holding member 56 via the hinge 56, that peripheral portion of the substrate W from sticking to the inner sealing member 62 and being brought up, which portion would otherwise be first brought up, and can effectively separate the substrate W from the inner sealing member 62.

0120It is also possible to use a suction pad of the so-called vacuum attraction type. In particular, though not shown diagrammatically, a vacuum line extends in the interior of the fixed holding member 54 and communicates with the interior of the suction pad. When the substrate is held by the substrate holder 18, the interior of the suction pad is vacuumed through the vacuum line, thereby attracting the substrate and holding it on the pad easily and securely. The holding of the substrate can be released by stopping the vacuuming.

0121The opening and closing of the movable holding member 58 is carried out through a not-shown cylinder and the weight of the movable holding member 58 per se. In particular, as shown in FIG.3, a through-hole 54a is formed in the fixedholding member 54 and the cylinder is provided at a location where the cylinder faces the through-hole 54a when the substrate holder 18 is placed on the loading plate 52. The movable holdingmember 58 is opened by extending a cylinder rod and allowing a pressing rod to pass through the through-hole 54 and press up the base portion 58a of the movable holdingmember 58, while the holding member 58 is closedby its own weight by contracting the cylinder rod.

0122According to this embodiment, locking/unlocking of the movable holding member 58 is effected by rotating the press ring 60. FIGS .8 and 9 show a locking/unlocking mechanism 110. The locking/unlocking mechanism 110 is provided on the ceiling side, and includes rotating pins 112 each at a location corresponding to each long hole 60a of the press ring 60 of the movable holding member 58 when the substrate W is placed in the substrate holder 18 on the loadingplate 52 and the movable holding member 58 is closed via the hinge 56. The rotating pins 112 are mounted vertically to the lower surface of a rotary plate 114 which is rotatable in both directions. The locking/unlocking mechanism 110 is also provided with vertically movable pressing rods 116 for pressing the support portion 58b of the movable holding member 58 of the substrate holder 18 on the loading plate 52 against the fixed holding member 54. In the rotaryplate 114 are formed circumferentially extending long holes 114a at locations corresponding to the pressing rods 116.

0123In operation, the substrate holder 18, with the substrate W placed therein and the movable holding member 58 closed, is raised alongwith the loadingplate 52 so as to locate the rotating pins 112 in the long holes 60a of the press ring 60. Thereafter, the pressing rods 116 are lowered to press the movable holding member 58 downward, thereby collapsing the sealing members 62, 68 so that the movable holding member 58 will not rotate. The rotating pins 112 are then rotated to thereby rotate the press ring 60, whereby each of the outwardly protruding portions of the press ring 60 is slipped into each of the clampers 74 to lock the movable holding member 58. By thus first lowering the pressing rods 116 so as to inhibit rotation of the movable holding member 58 and then rotating the press ring 60 via the rotating pins 112, the press ring 60 can be rotated with low friction. This reduces wear of the press ring 60, the clampers 74 and the movable holding member 58, and prevents the movable holding member 58 from corotating with the press ring 60, thereby preventing a displacement of the movable holdingmember 58 which would affect centering of the substrate W and distort the sealing members

012462,68 to lower their sealing abilities. It is possible to use a ring-shaped rotator instead of the rotating plate 114. Further, instead of the pressing rods

0125116, it is possible to use a cylindrical pressing member 116a as shown by the shaded area of FIG.9 so that the whole peripheral edge area of the substrate support 58b of the movable holding member 58 can be pressed evenly.

0126A single locking/unlocking mechanism 110 is provided. After locking (or unlocking) one of two substrate holders 18 placed on the loading plate 52, the loading plate 52 is slid laterally to lock (or unlock) the other substrate holder 18 withthe locking/unlockingmechanism110. The substrate holder 18 is provided with a sensor for inspecting the state of contact between the substrate W and the contacts of the substrate holder 18 when the substrate is held by the substrate holder 18. A signal from the sensor is inputted to a controller (not shown) .

0127To one end of the fixed holding member 54 of the substrate holder 18 is jointed a pair of substantially T-shaped hands

0128120 which serves as a support when the substrate holder 18 is transported or held in a hung state. In the stocker 24, the holder 18 is held in a vertically hung state with the protruding end portions of the hands 120 put on the upper surface of the circumferential wall of the stocker 24. The hands 120 of the thus hung substrate holder 18 are grasped by the transporter 42 of the substrate transport device 40 when transporting the substrate holder 18. Also in the pre-wetting tank 26, the presoaking tank 28, the water-washing tanks 30a, 30b, the blow tank 32 and the plating tank 34, the substrate holder 18 is held in a hung state with the hands 120 on the upper surface of the circumferential wall of each tank.

0129Next, a plating process will be described for plating a series ofbump electrodes usingtheplatingapparatus described above. As shown in FIG. 27A, a seed layer 500 as an electric feed layer is formed on the surface of a substrate. A resist 502 having a height H of e.g. 20-120 μ m is applied over the entire surface of the seed layer 500. Subsequently, an opening 502a having a diameter D of e.g. 20-200 //m is formed at a prescribed position in the resist 502. Such a substrate W is housed in the cassette 10 with the surface (surface to be plated) facing upward. The cassette 10 is loaded onto the cassette table 12.

0130The substrate transfer device 22 takes out one substrate from the cassette 10 on the cassette table 12 and places the substrate on the aligner 14. The aligner 14 aligns the orientation flat or notch or the like in the prescribed orientation. Next, the substrate transfer device 22 transfers the aligned substrate W to the substrate attaching/detaching section 20.

0131In the substrate attaching/detaching section 20, two substrate holders 18 housed in the stocker 24 are gripped simultaneously by the transporter 42 of the substrate holder transport device 40, and transported to the substrate attaching/detaching section 20. The substrate holders 18 are lowered in a horizontal state, and placed on the loading plate 52 of the substrate attaching/detaching section 20 simultaneously. The cylinders are operated to open the moveable supporting members 58 of the substrate holders 18. While the moveable supporting members 58 are open, the substrate transfer device 22 inserts the substrate into one of the substrate holders 18 positioned in the center of the substrate attaching/detaching section 20. The cylinder performs a reverse operation to close the moveable supporting member 58. Subsequently, the moveable supporting member 58 is locked by the locking/unlocking mechanism 110. After one substrate W is loaded into one substrate holder 18, the loading plate 52 is slid horizontally to load another substrate in the other substrate holder 18. Subsequently, the loading plate 52 is returned to its original position.

0132Thus, each surface of the substrate to be plated is exposed in the opening portion of the substrate holder 18. The sealing members 62, 68 seal the peripheral portion of the substrates W to prevent the plating solution from entering thereinto. Electricity is continued through the plurality of contacts in areas not in contact with the plating solution. Wiring is connected from the contacts to the hands 120 of the substrate holder 18. By connecting a power source to the hands 120, electricity can be supplied to the seed layer 500 formed on the substrate.

0133Next, the transporter 42 of the substrate holder transport device 40 grips both of the substrate holders 18 holding the substrate simultaneously, and transports the substrate holders 18 to the stoker 24. The substrate holders 18 are lowered with horizontal state so that two substrate holders 18 are suspended (temporarily placement) in the stocker 24.

0134The above process performed by the substrate transfer device 22, the substrate attaching/detaching section 20, and the transporter 42 of the substrate holder transport device

013540 is repeated in order to load substrate W one after another into the substrate holder 18 housed in the stocker 24 and suspend

0136(temporarily placement) the substrate holder 18 one after another at prescribed positions in the stocker 24.

0137When the sensor mounted on the substrate holder 18 for inspecting the contact state between the substrate and the contacts determines a poor contact, the sensor inputs the signal into a controller (not shown) . Meanwhile, the other transporter 44 of the substrate transport device 40 simultaneously grips two substrate holders 18 that have been holding the substrates and temporarily placed in the stocker 24. The transporter 44 transports the substrate holders 18 to the pre-wetting tank 26 and lowers to enter the substrate holders 18 into the pre-wetting tank 26.

0138However, if the sensor mounted on the substrate holder 18 for inspecting the contact state between the substrate and contacts has detected a poor contact state, the substrate holder 18 holding the substrate having the poor contact is left stored in the stocker 24. Accordingly, when a poor contact between a substrate and the contacts of the substrate holder 18 occurs, it does not halt the apparatus, but allows plating operations to continue. The substrate with a poor contact does not apply to the plating process. Instead the substrate is returned to the cassette and discharged from the cassette.

0139Next, the substrate holders 18 holding the substrates are transported in the same way as described above to the presoaking tank 28 and oxide layers of the substrates are etched away in the presoaking tank 28 to expose a clean metal surface . Next, the substrate holders 18 holding the substrates are transported in the same way to the cleaning tank 30a, wherein the surfaces of the substrates are cleaned by pure water held therein.

0140After the cleaning process, the substrate holders 18 holding the substrates are transported in the same way as described above to the plating tank 34 and suspended in the plating units 38. The transporter 44 of the substrate holder transport device 40 repeatedly performs this operation of transporting the substrate holder 18 to the plating unit 38 and suspending the substrate holder 18 at a prescribed position therein.

0141When the all substrate holders 18 are suspended in the plating units 38, plating voltages are applied between anodes (not shown) and the substrates, while the plating solution in the overflow tank 36 is circulating and overflowing into the overflow tank 36. At the same time, the paddle drive devices 46 reciprocate the paddles in a direction parallel to the surfaces of the substrates, thereby plating the surfaces of the substrates. At this time, each of the substrate holders 18 is fixed in a suspended state by the hands 120 at the top of the plating unit 38. Electricity is supplied from a plating power source to the seed layer 500 (see FIGS. 27A to 27C) via the conductors 86 and the electrical contacts 88.

0142After completion of the plating process, the application of plating voltages, supply of plating solution, and reciprocation of the paddles are all stopped. The transporter 44 of the substrate holder transport device 40 grips two of the substrate holders 18 holding the substrates simultaneously, and transports the substrate holders 18 to the cleaning tank 30b, as described above . The substrate holders 18 are immersed in pure water held in the cleaning tank 30b to clean the surfaces of the substrates W. Subsequently, the substrate holders 18 are transferred as described above to the blowing tank 32, where air is blown onto the substrate holders 18 holding the substrates to remove water droplets deposited thereon. Next, the substrate holders 18 are returned and suspended at prescribed positions in the stocker 24, as described above.

0143The above operation of the transporter 44 of the substrate holder transport device 40 is repeatedly conducted. After each substrate W has applied to the complete plating process, the substrate holders 18 are returned to the prescribed suspended position in the stocker 24.

0144Meanwhile, the transporter 42 of the substrate holder transport device 40 simultaneously grips two of the substrate holders 18 holding the substrates that have been returned to the stocker 24 after the plating process, and places the substrate holders 18 on the loading plate 52 of the substrate attaching/detaching section 20, as described above. At this time, a substrate for which a poor connection was detected by the sensor mounted on the substrate holders 18 for inspecting contact state between the substrate and contacts and which was left in the stocker 24 is also transported to the loading plate 52.

0145Next, the moveable supporting member 58 in the substrate holder 18 positioned at the center of the substrate attaching/detaching section 20 is unlocked by the locking/unlocking mechanism 110. The cylinder is operated to open the moveable supporting member 58. In this time, as described above, the substrate W can be prevented from sticking to themoveable supportingmember 58 whenthemoveable supporting member 58 is opened. In this state, the substrate transfer device 22 takes the plating processed substrate out of the substrate holder 18 and transfers the substrate to the spin dryer 16. The spin dryer 16 spins the substrate at a high rotational speed for spin-drying (draining) . The substrate transfer device 22 then transfers the substrate back to the cassette 10.

0146After the substrate is returned to the cassette 10, or during this process, the loading plate 52 is slid laterally, and the same process is performed for the substrate mounted in the other substrate holder 18 so that the substrate is spin-dried and returned to the cassette 10.

0147The loading plate 52 is returned to its original position . Next, the transporter 42 grips two of the substrate holders 18 which now hold no substrate simultaneously, and return the substrate holders 18 to the prescribed position in the stocker 24, as described above. Subsequently, the transporter 42 of the substrate holder transport device 40 grips two of the substrate holders 18 holding the substrates that have been returned to the stocker 24 after the plating process, and transports the substrate holders 18 onto the loadingplate 52, as described above. The same process is repeated.

0148The process is completed when all substrates have been taken out of the substrate holders, which have been holding substrates after the platingprocess and returned to the stocker 24, spin-dried and returned to the cassette 10. This process provides substrates W that have a plated film 504 grown in the opening 502a formed in the resist 502, as shown in FIG. 27B. The substrate W which has been spin dried, as described above, is immersed in a solvent, such as acetone, that is maintained at a temperature of 50-60°C, for example. In this process, the resist 502 is peeled off from the surface of the substrate W, as shown in FIG.27C. Next, the unnecessary seed layer 500 exposed after the plating process is removed, as shown in FIG. 27D, for thereby forming the bump 506.

0149In this example, the stocker 24 for housing the substrate holders 18 in a vertical position is provided between the substrate attaching/detaching unit 20 and plating units 38. The first transporter 42 of the substrate holder transport device 40 transports the substrate holders 18 between the substrate attaching/detaching unit 20 and stocker 24, and the second transporter 44 of the substrate holder transport device 40 transports the substrate holders 18 between the stocker 24 and plating units 38, respectively. Unused substrate holders 18 are stored in the stocker 24. This is designed to improve throughput by providing smooth transporting of the substrate holders 18 on either side of the stocker 24. However, it is of course possible to use one transporter to perform all transporting operations .

0150Further, a robot having a dry hand and a wet hand may be employed as the substrate transfer device 22. The wet hand is used only when taking out plating-processed substrates from the substrate holders 18. The dry hand is used for all other operations. In principle, the wet hand is not necessarily required since the backside of the substrate does not contact with plating solution due to the seal of the substrate holder 18. However, by using the two hands in this manner, it is possible to prevent a possible contamination with a plating solution due to poor sealing or invading to the backside of rinse water, etc. from contaminating the backside of a new substrate .

0151According to the substrate holder 18 of the above-described embodiment, such electrical contacts are employed as the electrical contacts 88 that have a positioning (centering) function for the substrate W and a function of preventing the substrate W from sticking to the sealing portion 62a of the inner sealing member 62 and being brought up along with the sealing portion 62a when taking the substrate W after plating out of the substrate holder 18. The structure of the substrate holder 18 can be simplified by the use of such electrical contacts 88. Besides electrical contacts, as shown in FIGS.10A to 10C, it is also possible to provide the movable holding member 58 with leaf spring members 140 having a positioning (centering) function for the substrate W, and a function of preventing the substrate W from sticking to the sealing portion 62a of the inner sealing member 62 and being brought up along with the sealing portion 62a when taking the substrate W after plating out of the substrate holder 18. The leaf spring member 140 may be disposed, for example, each at a location between two adjacent electrical contacts 88. The operation of the leaf spring members 140 is substantially the same as that of the above-described electrical contacts 88 shown in FIGS.5Ato5C, andhence a description thereof is here omitted.

0152Since the substrate W is biased inwardly by the elastic force of the leaf spring members 140, positioning (centering) of the substrate W relative to the substrate holder 18 upon holding of the substrate by the substrate holder 18 can be effected by the leaf spring members 140. Further, by providing the movable holding member 58 with the sealing member 62, the electrical contacts and the leaf spring members 140, and effecting the positioning of the substrate W by the leaf spring members 140, it becomes possible to make the positional relationship between the substrate W, the sealing member 62 and the electrical contacts always constant when the substrate W is held by the substrate holder 18.

0153In this regard, a precise centering can be effected with difficulty only through the engagement between the above-described tapered portions 82a, 90. This is because a clearance, if small, is necessary between the two tapered portions 82a, 90 in order to facilitate the engagement therebetween. Accordingly, the center of the substrate inevitablydeviates fromthe center of themovable holdingmember 58 by the clearance . In view of this, the movable holdingmember 58 is provided with the plurality of leaf spring members 140 so that they make an elastic contact with the peripheral edge of the substrate W and evenly apply a pressing force acting to move the substrate W toward the center of the movable member 58. Accordingly, when the movable holding member 58 engages the fixed holding member 54, the substrate W is shifted so that the center of the substrate can coincide exactly with the center of the movable holding member 58.

0154Though in the above-described embodiment each leaf spring member 140 is comprised of a single plate formed in the shape of a leaf spring, the leaf spring member 140 may be comprised of a leaf spring-shaped laminate of two or more plates, for example, a laminated leaf spring 124 consisting of plates 122a, 122b shown in FIG. 11. Such leaf spring members 140 (laminated leaf springs 124) can secure a long stroke without a plastic deformation and can be set in a considerably small space. Positioning (centering) of the substrate W with respect to the substrate holder 18 can be effected by the leaf spring members 140 (laminated leaf springs 124) in the course of holding the substrate W by the substrate holder 18. Further, when the substrate W after plating is taken out the substrate holder 18, the laminated leaf springs 124 can prevent the substrate W from sticking to the sealing portion 62a of the inner sealing member 62 and being brought up along with the inner sealing member 62.

0155Further, as shown in FIGS. 12 through 14, it is possible to use as the inner sealing member 62 a multi-seal structure 128 comprising two ring-shaped sealing portions 126a, 126b on both sides inthe widthdirection, andpartition sealingportions 126c extending in the width direction and provided at certain locations along the circumferential direction. By sealing a peripheral portion of the substrate W with the sealing member 62 comprised of the multi-seal structure 128, the sealing width is substantially widened, so that a more complete sealing can be attained even when the centering of the substrate is not perfect. Further, by sealing the certain portions along the circumferential direction of the inner sealing member 62 with the partition sealing portions 126c in the width direction, it becomes possible to maintain the sealing ability of the inner sealing member 62 even when it is damaged.

0156In particular, as shown in FIGS. 13A and 13B, due to a deviation in the centering of the substrate W, there may be a case where the sealing portion 126b, positioned on the inner side of the multi-seal structure 128, crosses over a resist line R having a step on the surface of the substrate (FIG.13A) , or a case where the sealing portion 126a, positioned on the outer side of the multi-seal structure 128, crosses over the resist line R (FIG. 13B) . Even in such cases, at least one of the sealing portions 126a, 126b, not crossing over the resist line R, constitutes a sealing line, as shown by the shaded lines in FIGS. 13A, 13B, whereby sealing is ensured if a liquid leak occurs at the crossing portion. Further, if the sealing portions 126a, 126b are damaged, for example at sites Xi and X₂ close to each other and on both sides of the partition sealing portion 126c as shown in FIG. 13B, the sealing ability can be maintained with the partition sealing portion 126c positioned between the damaged sites Xi and X₂.

0157FIG. 15 shows a substrate holder according to another embodiment of the present invention. The substrate holder of this embodiment differs from the above-described substrate holder in that on the movable holding member 58 side surface of the fixed holder member 54 is provided a pair of conducting lines (conductors) 130 for detecting a liquid leak which, when a plating solution leaks to the back surface side of the substrate W held by the movable holding member 58 and the fixed holding member 54, short-circuits via the leaked plating solution. The pair of conducting lines 130 extends continuously and circumferentially on the surface of the fixed holding member 54 such that it extends over almost the whole peripheral back surface of the substrate W. Further, the pair of conducting line 130 is open at one end, and at the other end is connected to an electric resistance measuring device 132. The other construction is the same as the above-described substrate holder.

0158According to this embodiment, occurrence of a liquid leak can be detected quickly and securely by measuring the electric resistance between the pair of conducting lines 130 by the electric resistance measuring device 132. Thus, the pair of conductinglines 130 is open at one end, and therefore an electric current usually does not flow. However, when a leak of plating solution occurs, the plating solution, which is a conductor, short-circuits the pair of conducting lines 130 whereby an electric current flows through the conducting lines 130. That is, the plating solution behaves like a resistance R, as illustrated by the imaginary lines in FIG. 15, which short-circuits the pair of conducting lines 130. Accordingly, measurement of the electric resistance via the electric current can detect the leak of plating solution.

0159According to this embodiment, the pair of conducting lines (conductors) is disposed such that it extends continuously over the whole peripheral back surface of the substrate. By thus disposing the pair of conducting lines right inside the peripheral sealingportionof the substrate, itbecomes possible to immediately detect a leak wherever the leak occurs. Alternatively, unlike this embodiment, it is also possible to provide a pair of conducting lines at any location, for example, a location where a leaked liquid is likely to collect, or provide a plurality of pairs of conducting lines in parallel. For instance, as shown in FIG. 16, a pair of conductive plates (conductors) 142, connected to a pair of electrodes respectively, may be disposed opposite to each other at a predetermined spacing at the bottomportion of the fixed holding member 54 where a plating solution piles up in case a leak of the solution occurs. An electric current flows between the conductive plates 142 via the plating solution when the solution piles up at the bottom portion of the fixed holding member 54 after the occurrence of the leak . According to this embodiment, by disposing the conductive plates 142 at such a local location as the bottom portion of the fixed holding member 54, a liquid leak over the whole area of the substrate holder 18 can be detected.

0160As described hereinabove, according to the plating apparatus of the present invention, by simply setting a cassette housing substrates on the cassette table and activating the apparatus, electroplating employing a dipping method can be carried out fully automatically to form a plated metal film suited for the formation of bumps .

0161Further, according to the present invention, a suction pad for attracting the back surface of the substrate, held by the fixed holding member and the movable holding member, may be mounted to the fixed holding member . Since the back surface of the substrate is kept attracted to the suction pad, when the movable holding member is moved after plating to release the holding of the substrate and take the substrate out of the substrate holder, the substrate can be prevented from sticking to the inner sealing member and moving along with the inner sealing member. The substrate can thus be taken out of the substrate holder in a stable manner.

0162Further, since the inner sealing member for sealing a peripheral portion of the substrate may be integrally mounted on a holding member for holding the inner sealing member, when the movable holding member is moved after plating to release the holding of the substrate and the substrate is taken out of the substrate holder, the sealingportion of the inner sealing member can be prevented from adhering to the substrate, and hence the inner sealing member can be prevented from being torn off fromthe holdingmember . Releasability of the inner sealing member from the substrate can thus be improved.

0163Further, the outer sealing member for sealing between the movable holding member and the fixed holding member may be one that has a W-shaped cross-section, easily collapse when pressed in the width direction and recovers by the elastic force when the pressing force is released. The use of such an outer sealingmember can facilitate its insert into the seal groove, e.g. in a dovetail shape, and prevent it from falling from the seal groove. Further, a leaf springmember maybe mounted on the movable holding member so that the substrate is biased toward the fixed moving member when the holding of the substrate between the moveable holdingmember andthe fixedholdingmember is released. Accordingly, when the movable member is moved after plating to release the holding of the substrate and take the substrate out of the substrate holder, movement of the substrate is restricted and the inner sealing member mounted on the movable holding member is detached from the substrate, whereby the substrate can be prevented from sticking to the inner sealing member and moving along with the inner sealing member.

0164Furthermore, the movable holding member may be provided with at least one pair of conductors for detecting a liquid leak which, when a plating solution leaks to the back surface side of the substrate held by the movable holding member and the fixed holding member, short-circuits via the leaked plating solution. This enables an immediate detection of occurrence of a liquid leak and makes it possible to deal with the liquid leak promptly, thereby preventing the liquid leak from adversely affecting the apparatus and the quality of plating.

0165FIGS. 17 through 22F show a substrate holder according to still another embodiment of the present invention. The substrate holder has a fixed holding member 154 made of, for example, a vinyl chloride resin in the form of a rectangular flat plate, and a movable holding member 158 mounted openably and closably via a hinge 156 on the fixed holding member 154. While the movable holding member 158 is shown as being openably and closably mounted on the fixed holding member 154 by the hinge 156 in present embodiment, the movable holding member 158 may be disposed in a position facing the fixed holding member 154 and may be moved forward to the fixed holding member 154 so as to be opened and closed with respect thereto. The movable holding member 158 has a base portion 158a and a ring-shaped support portion 158b, and is made of, for example, a vinyl chloride resin for better slippage against a below-described press ring 162. A ring-shaped sealingmember

0166(seal ring) 160 that is of a substantially channel-shaped transverse cross section having two lips, one being longer than the other, is mounted on a surface of the support portion 158b which faces the fixedholdingmember 154, the ring-shaped sealing member 160 being open toward the fixed holding member 154. The press ring 162 is rotatably supported on a surface of the support portion 158b on the far side fromthe fixedholding member 154, and slide plates 164 are jointed to outer circumferential surfaces of the press ring 162. The press ring 162 is made of, for example, titanium that is highly resistant to corrosion in oxidizing environments and has sufficient rigidity.

0167Inverted L-shaped clampers 170, each having an inward protrusion, are vertically mounted on the fixed holding member 154 at circumferentially equal spaced intervals in positions laterally outward of the slide plates 164. The surfaces of the slide plates 164, and the lower surfaces of the inward protrusions of the clampers 170, which are positionedin covering relation to the surfaces of the slide plates 164, are tapered so as to be slanted oppositely to each other in the rotational direction. Projections 173, which comprise rotary pins threaded into the press ring 162, for example, are mounted on the surface of the press ring 162 respectively in a plurality of locations (e.g., four locations) along the circumferential direction of the press ring 162. The projections 173 are engaged by a rotating mechanism (locking/unlocking mechanism) for rotating the press ring 162 in unison with the slide plates 164.

0168When the movable holdingmember 158 is open, the substrate W is inserted into the center of the fixed holding member 154. After the movable holding member 158 is closed about the hinge 156, the press ring 162 is turned clockwise to cause the slide plates 164 to slide into the protrusions of the clampers 170, thereby fastening and locking the fixed holding member 154 and the movable holding member 158 to each other through their tapered surfaces. By turning the press ring 162 counterclockwise, the slide plates 164 are removed from the protrusions of the L-shaped clampers 170, unlocking the fixed holding member 154 and the movable holding member 158 from each other. When the movable holdingmember 158 is locked, a shorter lip 160a on the inner circumferential surface of the sealing member 160 is in pressure contact with the surface of the substrate W, and a longer lip 160b on the outer circumferential surface of the sealing member 160 is in pressure contact with the surface of the fixed holdingmember 154, respectively. The sealing member 160 is thus uniformly pressed against the substrate W and the fixed holding member 154 to seal the surface of the substrate W and the surface of the fixed holding member 154 reliably.

0169A ridge 182 is mounted centrally on and projects from the fixed holding member 154 in a ring shape matching the size of the substrate W. The ridge 182 provides a support surface 180 for abutting against the peripheral edge of the substrate W to support the substrate W thereon. The ridge 182 has a plurality of recesses 184 defined therein at predetermined positions along the circumferential direction thereof.

0170As shown in FIGS. 17, 20A and 20B, a plurality of (eight in the illustrated embodiment) conductors (electrical contacts) 188 are disposed respectively in the recesses 184 and connected to respective wires extending from external contacts on a below-described hand 198. When the substrate W is placed on the support surface 180 of the fixed holding member 154, the conductors 188 have their springy ends exposed on the surface of the fixed holding member 154 laterally of the substrate W.

0171A support body 190 is mounted in an inner space of the sealing member 160 which is defined between the lips 160a, 160b . Electrical contacts 192 have respective legs 192a fixed to the support body 190 at positions confronting the conductors 188. Each electrical contact 192 is formed in a leaf springs shape. Specifically, the electrical contacts 192 have contact ends 192b projecting inwardly as leaf springs that can easily flex under their own resiliency.

0172As shown in FIG. 26A, the contact ends 192b are arranged as a plurality of parallel rectangular strips projecting equal lengths toward the substrate W. The electrical contacts 192 are attached to the support body 190 such that a line interconnecting the tips of the contact ends (strips) 192b is slightly inclined to a tangential direction of the substrate W. As shown in FIG. 26A, therefore, the tips of the contact ends (strips) 192b are held in contact with a contact area A, shown hatched, on the surface of the substrate W in respective different positions in the transverse direction of the contact area A. Even if the substrate W suffers a slight positioning error, at least some of the tips of the contact ends (strips) 192b are brought into contact with the substrate W in the contact area A thereof.

0173Alternatively, as shown in FIG. 26B, a plurality of elongated electrical contacts 192 may be disposed at predetermined spaced intervals across the diametrical direction of the substrate W, and may have respective contact ends 192b having respective tips held in contact with a contact area A, shown hatched, on the surface of the substrate W in respective positions along the circumferential direction of the contact area A. With this arrangement, even if dirt or the like is attached to the contact ends 192b of some of the electrical contacts 192, the other electrical contacts 192 are kept in electrical connection to the substrate W.

0174Further alternatively, as shown in FIG. 26C, the electrical contacts 192 may be attached to the support body 190 such that a line interconnecting the tips of the contact ends (strips) 192b, which are arranged as a plurality of parallel rectangular strips projecting equal lengths toward the substrate W, extends parallel to a tangential direction of the substrate W. Still further alternatively, as shown in FIG. 26D, the contact ends (strips) 192b, which are arranged as a plurality of parallel rectangular strips, may project respective different lengths toward the substrate W. With these modifications, the tips of the contact ends (strips) 192b are held in contact with the contact area A, shown hatched, on the surface of the substrate W in respective different positions in the transverse direction of the contact area A. Even if the substrate W suffers a slight positioning error, at least some of the tips of the contact ends (strips) 192b are brought into contact with the substrate W in the contact area A thereof.

0175When the movable holding member 158 is locked to hold the substrate Wwith the fixedholdingmember 154 and the movable holdingmember 158, as shown in FIG. 20B, the exposed portions of the conductors 188 are resiliently held in contact with and electrically connected to the lower surfaces of the legs 192a of the electrical contacts 192 under the resiliency of the exposed portions of the conductors 188 in a position sealed by the sealingmember 160, i.e., a region sandwiched between the lips 160a, 160b of the sealing member 160. The substrate W is thus resiliency held in contact with the tips of the contact ends 192b of the electrical contacts 192 under the resiliency of the contact ends 192b. In this manner, while the substrate W is being sealed by the sealing member 160 and held by the substrate holder, the substrate W can be supplied with electric energy through the electrical contacts 192.

0176Since the electrical contacts 192 are in the form of leaf springs toholdthe tips of the contact ends 192b of the electrical contacts 192 in contact with the substrate Wunder the resiliency of the electrical contacts 192, contact failures are reduced, and the electrical contacts 192 are held in contact with the substrate W in an outer circumferential region thereof, thus increasing an area of the substrate W that can effectively be used as a pattern formation area.

0177At least the surfaces of the conductors 188 which are to be held against the electrical contacts 192 may preferably be plated with gold or platinum.

0178As shown in FIGS. 21A and 21B, the ridge 182 of the fixed holding member 154 partly has a tapered portion 182 with a steeple-shaped tapered surface, and the inner circumferential surface of the support body 190 has a tapered portion 190a which complementarily faces the tapered portion 182a. When the fixed holding member 154 and the movable holding member 158 hold the substrate W, the tapered portions 182a, 190a engage each other to position the fixed holding member 154 and the movable holding member 158 in central alignment with each other. Specifically, as shown in FIG. 21B, when the fixed holding member 154 and the movable holding member 158 hold the substrate W, the tapered portions 182a, 190a guide each other, positioning the movable holding member 158 with respect to the fixed holding member 154 or positioning the fixed holding member 154 with respect to the movable holding member 158.

0179Because of the tapered portions 182a, 190a of the ridge 182 of the fixed holding member 154 and the support body 190 of the movable holding member 158, even if the fixed holding member 154 and the movable holdingmember 158 are not accurately positionally aligned with respect to each other when they are spaced from each other, they can automatically positioned aligned with each other by the tapered portions 182a, 190a while the fixed holding member 154 and the movable holding member 158 are in the process of holding the substrate W. The tapered portion 190a of the support body 190 of the movable holding member 158 serves to guide the outermost circumferential edge of the substrate W supported on the support surface 180 of the ridge 182 of the fixed holding member 154 to position the substrate W, when the fixed holding member 154 and the movable holding member 158 hold the substrate W. Specifically, as shown in FIG. 21B, when the outer circumferential portion of the substrate W projects outwardly from the support surface 180 of the ridge 182, the outermost circumferential edge of the substrate W contacts the tapered portion 190a, positioning (centering) the substrate W with respect to the substrate holder and hence the sealing member 160. Thus, while the fixed holding member 154 and the movable holding member 158 are in the process of holding the substrate W, they are centrally positioned with respect to each other, and at the same time the tapered portion 190a of the support body 190 of the movable holding member 158 positions (centers) the substrate W with respect to the substrate holder.

0180Furthermore, as shown in FIGS. 22A to 22F, a plurality of grooves 194 are defined in the surface of the fixed holding member 154 at positions along the circumferential direction which face the sealing member 160. Leaf spring members 196 which extend upwardly are disposed respectively in the grooves 194 with their lower ends fixed in position. The leaf spring members 196 are made springy with their lower ends being fixed and upper ends being free. The leaf spring members 196 have springy extensions (free end portions) 196a which extend outwardlyobliquelyin the upwarddirection and arcuate engaging portions 196b on the tip ends of the extensions 196a.

0181The support body 190 of the movable holding member 158 has , onits inner circumferential surfaces facingthe leaf spring members 196, guide surfaces each comprising a tapered surface 190c slanted inwardly in the upward direction and a vertical surface 190d extending vertically contiguously to the tapered surface 190c.

0182As shown in FIGS. 22A and 22B, as the movable holding member 158 is lowered, the engaging portion 196b on the tip of each leaf spring member 196 is engaged and guided by the tapered surface 190c, causing the leaf spring member 196 to be bent inwardly. Upon further downwardmovement of themovable holdingmember 158, as shown in FIG.22C, the engaging portion 196b on the tip of the leaf spring member 196 is positioned inwardly of the vertical surface 190d, causing the extension 196a to extend vertically, whereupon the leaf spring member 196 will not be bent further inwardly. The engaging portion 196b of the leaf spring member 196 is now positioned over the outer circumferential edge of the substrate W which is supported on the support surface 180 of the fixed holding member 154. Continued descent of the movable holding member 158 presses the shorter lip 160a on the inner circumferential side of the sealing member 160 against the surface of the substrate W and also presses the longer lip 160b on the outer circumferential side of the sealingmember 160 against the surface of the fixed holding member 154, respectively, thus uniformly pressing the sealing member 160 to seal the substrate W and the fixed holding member 154 securely. The substrate W is then processed, e.g., plated.

0183After a series of the processing of the substrate W is finished, the movable holdingmember 158 is elevated to remove the substrate W which has been held by the substrate holder. At this time, as shown in FIG. 22D, since the engaging portion 196b on the tip of the leaf spring member 196 is positioned inwardly of the vertical surface 190d, the leaf spring member 196 is limited in its movement. Consequently, even if the substrate W is sticking to the sealingmember 160, the engaging portion 196b on the tip of the leaf spring member 196 engages the upper surface of the outer circumferential surface of the substrate W, preventing the substrate W from ascending. The sealing member 160, the movable holding member 158, and the support body 190 are lifted, forcing the substrate W off the sealing member 160. When the movable holding member 158 is further elevated, as shown in FIG. 22E, the engaging portion 196b on the tip of the leaf spring member 196 spreads progressively outwardly under its own resiliency while in abutment against the tapered surface 190c of the support body 190, until it returns to its original position as shown in FIG. 22F. At this time, the engaging portion 196b of the leaf spring member 196 is positioned outwardly of the outer circumferential portion of the substrate W which is supported on the support surface 180 of the fixed holding member 154. Therefore, the processed substrate W is not prevented from being taken out of the substrate holder by the leaf spring member 196, and a substrate to be processed is not prevented by the leaf spring member 196 from being inserted in place.

0184Accordingly, after the substrate W has been plated, when the movable holdingmember 158 is moved to release the substrate W and the substrate W is taken out of the substrate holder, the substrate W is prevented from sticking to and moving with the sealing member 160. Since the free end of the leaf spring member 196 is positioned outwardly of the outer circumferential portion of the substrate W when the movable holding member 158 is thus moved, the substrate W is not prevented from being taken out of substrate holder. As described above, the sealing member 160 has the lips 160a, 160b for contacting the circumferential edge of the substrate W and the surface of the fixed holding member 158, respectively, when the substrate W is held by the fixed holding member 158 and the movable holding member 154, and the sealing memberl 160 is held integrally by the support body 190 which is disposed between the lips 160a, 160b. Specifically, the sealing member 160 has a flat portion joining the lips 160a, 160b and sandwiched between the support portion 158b of the movable holdingmember 158 and the supportbody 190. The sealing member 160 is fixed in position by fastening the support portion 158b of the movable holding member 158 and the support body 190 with bolts 91 (see FIGS. 21A and 21B) . Further, on the upper surface of the sealing member 160 is integrallyprovidedapair of radially spaced sealingportions 193 which makes contact with the lower surface of the support portion 158a of the movable holding member 158. The bolts 191 are disposed between the pair of sealing portions 193, and the sealing member 160 is fixed between the support 190 and the support portion 158a by fastening the bolts 194 to squash the sealing portions 193. This prevents a leak of water from the interstice between the support portion 158a and the sealing member 160, shown by the arrow in FIG. 21A, even when a force is applied to the lip portions 160a, 160b of the sealing member

0185160 in such a direction (downward direction) that it forces the lip portions 160a, 160b away from the support portion 158b .

0186Inasmuch as the sealing member 160 is held integrally on the support body 190, when the movable holding member 158 is moved to release the substrate W and the substrate W is taken out of the substrate holder after the substrateWhas been plated, the lip (seal) 160a of the sealingmember 160 is prevented from sticking to the substrate W and being turned up from the support portion 158b of the fixed holding member 158 , thereby improving the peelability between the sealingmember 160 and the substrate W.

0187The movable holding member 158 is opened and closed by a cylinder (not shown) and the weight of the movable holding member 158 per se. Specifically, the fixedholdingmember 154 has a through-hole 154a, as shown in FIG. 19, and a cylinder is disposed in a position which confronts the through-hole 154a of the substrate holder placed on a loading plate 152. When the piston rod of the cylinder is extended to cause a pusher rod to lift the base portion 158a of the movable holding member 158 through the through-hole 154a, thereby opening the movable holding member 158. When the piston rod is contracted, the movable holding member 158 is closed under its own weight. In the present embodiment, the press ring 162 is rotated to lock and unlock the movable holding member 158. A locking/unlocking mechanism for locking and unlocking the movable holding member 158 is mounted on the ceiling side . The locking/unlocking mechanism has gripping members disposed in respective positions aligned with the projections 173 of the press ring 162 of the centrally positioned substrate holder placed on the loading plate 152. The locking/unlocking mechanism is arranged to rotate the press ring 162 when the gripping members are turned about the axis of the press ring 162 with the loading plate 152 being lifted and the projections 173 being gripped by the gripping members. There is a single locking/unlocking mechanism being used, and after the locking/unlocking mechanism locks (or unlocks) one of two substrate holders placed on the loading plate 152, the loading plate 152 is slid horizontally, and the locking/unlocking mechanism locks (or unlocks) the other substrate holder.

0188The substrate holder has a sensor for inspecting a state of contact between the substrate W and the contacts when the substrate W is held with the substrate holder. A signal from the sensor is supplied to a controller (not shown) .

0189A pair of substantially T-shaped hands 198 is jointed to an end of the fixedholdingmember 154 of the substrate holder. The hands 198 serve as supports at the time of transporting the substrate holder, and suspending and supporting the substrate holder.

0190In the above embodiment, the tips of the contact ends 192b of the electrical contacts 192 are resiliently held in contact with the surface of the substrate W that is supported on the support surface 180 of the fixed holding member 154. However, as shown in FIGS. 23A and 23B, when the fixed holding member 154 and the movable holding member 158 hold the substrate W, the contact ends 192b of the electrical contacts 192 may resiliently contact the outer circumferential surface of the substrate W that is supported on the support surface 180 of the fixed holding member 154, so that the electrical contacts 192 serve both as contacts and leaf spring members for positioning the substrate W. When the substrate holder holds the substrate W, since the substrate W is biased inwardly under the resiliency of the electrical contacts 192 in the form of leaf spring members, the electrical contacts (leaf spring members) 192 can effect the positioning (centering) of the substrate W with respect to the substrate holder. Because the sealing member 160 and the electrical contacts 192 are provided on the movable holding member 158 and the substrate W is positioned with respect to the substrate holder by the electrical contacts 192, when the substrate W is held by the substrate holder, the substrate W, the sealing member 160, and the electrical contacts 192 are always kept in constant positional relationship to each other.

0191As sown in FIGS. 24A to 24F, electrical contacts/leaf spring members 200 which serve both as the above-described electrical contacts 192 and the above-described leaf spring members 196maybe disposedin recesses 202 definedin the surface of the fixedholdingmember 154 at predetermined positions along the circumferential directions in facing relation to the sealing member 160.

0192The electrical contacts/leaf spring members 200 differ in operation from the above-described leaf spring members 196 in that, as shown in FIG. 24C, when an engaging portion 200b on the tip of each electrical contacts/leaf spring member 200 is positioned inwardly of a vertical surface 190d of the support body 190, with an extension 200a extending vertical, preventing the electrical contacts/leaf spring ember 200 from being bent further, the electrical contacts/leaf springmember 200 is held in contact with the outer circumferential portion of the substrate W that is supported on the support surface 180 of the fixed holding member 154 to supply the substrate W with electric energy. When the substrate W is to be released, the engaging portion 200b on the tip of the electrical contacts/leaf spring member 200 is continuously held in abutment against the outer circumferential portion of the substrate W, only the sealing member 160 is lifted to force the substrate W off the sealing member 160. Other operational details of the electrical contacts/leaf spring members 200 are the same as the leaf spring members 196 shown in FIGS. 22A to 22F. With the electrical contacts/leaf spring members 200 which serve both as the electrical contacts 192 and the leaf spring members 196, it is not necessary to provide dedicated leaf spring members for the sole purpose of separating the substrate W from the sealing member when the substrate holder releases the substrate W, and hence the substrate holder can be simplified in structure.

0193Although not shown, when the fixed holding member 154 and the movable holding member 158 hold the substrate W, the engaging portion 200b on the tip of the electrical contacts/leaf spring member 200 may be resiliently held against the outer circumferential surface of the substrate W that is supported on the support surface 180 of the fixed holding member 154, and when the substrate W is held by the substrate holder, the substrate W may be biased inwardly under the resiliency of the electrical contacts/leaf spring member 200, so that the substrate W may be positioned (centered) with respect to the' substrate holder by the electrical contacts/leaf spring member 200. Furthermore, as shown in FIGS.25A and 25B, a leaf spring member 210 which is springy to be resiliently held against the outer circumferential end of the substrate W to position the substrate W when the fixed holding member 154 and the movable holding member 158 hold the substrate W, may be supported on the support body 190 separately from the electrical contact 192. The leaf spring member 210 may be disposed in a position between two adjacent electrical contacts 192 shown in FIGS. 20A and 20B, for example. Intheprocess ofholdingthe substrateWwiththe substrate holder, the substrate W is biased inwardly under the resiliency of the leaf spring member 210, and hence positioned (centered) with respect to the substrate holder by the leaf spring member 210. Since the sealing member 160, the electrical contacts 192, and the leaf spring members 210 for positioning the substrate are mounted on the movable holding member 158, and the substrate W is positioned by the leaf spring members 210, when the substrate W is held by the substrate holder, the substrate W, the sealingmember 160, and the electrical contacts 192 are always kept in constant positional relationship to each other by the leaf spring members 210.

0194As described above, the plating apparatus according to the present invention carries out an electroplating process of the dipping type full automatically for automatically forming a plated film of metal suitable for bumps, etc. on the surface of a substrate by setting a cassette housing the substrates on a cassette table and starting to operate the plating apparatus .

0195According to the present invention, as described above, since the electrical contacts are constructed as form of leaf springs and brought into contact with the substrate under their own resiliency, contact failures are reduced, andthe electrical contacts are held in contact with the substrate in an outer circumferential region thereof, thus increasing an area of the substrate that can effectively be used as a pattern formation area.

0196The fixed holding member and the movable holding member have respective tapered portions for engaging each other positioning them centrally with respect to each other when they hold the substrate. Therefore, in the process of holding the substrate with the fixed holding member and the movable holding member, the fixed holding member and the movable holding member are automatically positioned in central alignment with each other by the tapered portions that engage each other.

0197Furthermore, the leaf spring member is disposed in the region of the fixed holdingmember where is sealed by the sealing member when the substrate is held. The leaf spring member has its free end positioned inwardly of the outer circumferential edge of the substrate when the substrate is held with the fixed holding member and the movable holding member, and positioned outwardly of the outer circumferential edge of the substrate when the substrate is released from the fixed holding member and the movable holdingmember . Therefore, after the substrate has been plated, when the movable holding member is moved to release the substrate and the substrate is taken out of the substrate holder, the substrate is prevented from sticking to and moving with the sealing member, and possibly from being dislodged out of position.

0198Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.

0199Industrial Applicability

0200The present invention relates to a substrate holder for use in a plating apparatus for forming a plated film in fine interconnect trenches or holes, or resist openings provided in the surface of a semiconductor wafer, or for forming bumps (protruding electrodes) , which are tobe electrically connected to electrodes, etc. of a package, on the surface of a semiconductor wafer.