Polishing medium stabilizer

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field]

The present invention relates to the field of polishing and, in particular, to chemical mechanical polishing. More specifically, it is an object of the present invention to improve the holding property of the polished surface and the holding property of the polishing liquid during polishing.

【0002】

[Background technology]

Polishing the product to form a smooth mirror surface can be used in various fields of industry. Such a polishing process is becoming extremely important and widespread in the manufacture of semiconductor devices and the like. Important steps are required to polish semiconductor wafers or substrates at many different stages through the various steps used to manufacture semiconductor devices.

【0003】

Chemical mechanical polishing is rapidly beginning to be adopted as a technique for polishing substrates, especially as a technique for use when manufacturing semiconductor devices on wafers or substrates. The device is usually connected by a step called metallization in which connecting wires of metal such as aluminum or copper are routed by vacuum deposition or other suitable steps.

【0004】

The performance levels of conventional semiconductor devices using a single metal layer connecting the devices are rapidly becoming unacceptable. The latest high performance equipment uses multi-layer metal wiring. The multilayer wiring deposits a dielectric layer or an insulating layer on the first metal layer, etches a via hole penetrating the dielectric layer, and fills the via hole for connecting to the first metal layer. It can be constructed by depositing a second metal layer. These devices can increase the device density and shorten the wiring length between devices.

【0005】

Since each of these metal layers and dielectric layers has a considerable thickness, when various layers are layered one after another and patterned, an uneven shape remains on the wafer substrate. This type of non-flatness is often unacceptable in high density equipment. This is because the lithographic equipment used to print a circuit on a wafer, the narrower the wiring width of the circuit, the more the depth of focus of the lithographic equipment becomes, even if the flatness of the wafer varies slightly. Even so, it is not possible to obtain a depth of focus sufficient to correct it.

【0006】

Wafer polishing or flattening during the manufacturing process must be responsible not only for the non-flatness caused by the device patterns formed, but also for variations in flatness throughout the wafer. In the manufacturing process, the wafer may, for example, bend or distort.

【0007】

Therefore, the apparatus for polishing in the manufacturing process is required not only to have unevenness and fluctuation of the wafer due to these pattern shapes, but also to have a special ability to realize a uniformly flat wafer surface throughout. Chemical mechanical polishing is widely accepted as an effective means of achieving the overall flatness of the wafer surface required for state-of-the-art equipment using multi-layer metallization.

【0008】

A typical chemical mechanical polishing apparatus includes a wafer carrier having a substantially circular pressure plate or carrier platen that supports a single substrate or wafer. A carrier film may be inserted between the carrier platen and the wafer. The wafer carrier comprises means for applying a downward force, pressing the wafer against a polishing medium (typically a circular pad), and a polishing liquid is supplied on the polishing medium. The polishing medium is supported by a polishing platen. The polishing liquid may be composed of a colloidal suspension of an abrasive material, or may be composed of a chemically reactive solution. Generally, a containment ring surrounds the wafer and prevents the wafer from shifting from the carrier platen during polishing.

【0009】

Typically, the relative motion of the wafer to the pad is chemical in the presence of a chemically reactive abrasive and / or an abrasive containing an abrasive and in the presence of force from the wafer carrier. It gives the wafer a combination of mechanical and mechanical action, which ultimately flattens the wafer surface as a whole. In general, the abrasive platen can rotate, as does the carrier platen. In a typical polishing apparatus, the relative motion of the wafer with respect to the pad is made by rotating the polishing platen, the carrier platen, or both.

【0010】

Typically, the rotating platen mechanism is fitted with a circular polishing pad, which gives satisfactory results as it wears out or becomes clogged with abrasive fluid and abrasive particles and becomes slippery. It will be used until it can no longer be used. At that point, the polishing process must be interrupted and the polishing pad replaced. In another mechanism, a rectangular pad may be used. That is, the pad material is continuously supplied, and the pad material is sent out to the polishing platen in predetermined amounts, and the polishing pad is never worn too much to be ineffective.

【0011】

Regardless of the form of the polishing pad, a common problem that arises when the pad is not fixed to the polishing platen by adhesive or other mounting means is that polishing pressure is applied to the polishing pad from the wafer carrier through the wafer. Sometimes the polishing pad moves from its predetermined position. This movement occurs because the frictional force between the wafer and the polishing pad, including any chemical polishing medium that may be used, is greater than the frictional force present between the polishing pad and the polishing platen. To do. Such movement reduces productivity and also reduces the accuracy of the polishing process, which is required to reduce the polishing pressure used in the process as much as possible, thus increasing the polishing time. To make matters worse, the polishing pad can buckle as it moves, resulting in non-flat polishing results or complete failure of the process (eg, substrate breakage). These problems are not limited to chemical mechanical polishing, but can also occur in purely mechanical polishing processes.

【0012】

A problem that occurs especially in a chemical mechanical polishing apparatus is that the chemical liquid or slurry between the substrate to be polished and the polishing pad is depleted when the polishing operation is performed to some extent. Due to the relatively smooth and flat surface that makes up the polishing pad / platen and the surface of the substrate to be polished, the polishing operation tends to "sweep out" chemical liquids / slurries with the surface of the substrate to be polished. A vacuum state or negative pressure gradually increases between the polishing pad and the polishing pad. Therefore, this problem is exacerbated over time for polishing. Also, ironically, this problem becomes more serious as the surface of the substrate becomes flatter and smoother, further reducing the efficiency of polishing and the efficiency of the process.

【0013】

It is desirable to have a device that can immobilize the polishing pad and at the same time allow the polishing pad to be replaced easily and quickly, either continuously or intermittently. It is also desirable to prevent the elimination of chemical polishing agents, such as the phenomenon known as "slurry deficiency" between the substrate surface to be polished and the polishing pad.

【0014】

[Summary of Invention]

The present invention attempts to solve the above-mentioned problems, among other advantages that will be revealed in the following detailed description. Devices for stabilizing the polished surface are a substantially flat, inflexible support base, a flexible polishing pad on the support base, and on the support base and in the support base and on the polishing pad. Includes a vacuum port underneath. When negative pressure is applied through the vacuum port, the polishing pad is attracted to the support base and the polishing pad is kept in place. Preferably, a seal is provided and forms an outer circumference around the vacuum port on the support base. When applying negative pressure, an airtight state is formed between the support base and the polishing pad along the seal.

【0015】

In another embodiment, multiple vacuum ports are used to more evenly disperse the applied negative pressure. For example, a plurality of vacuum ports may be arranged along the outer circumference of the support base. Alternatively, the plurality of vacuum ports may be arranged substantially uniformly over the entire support base. The plurality of vacuum ports includes a group of relatively larger vacuum ports along the outer circumference of the support base and a group of relatively smaller vacuum ports arranged almost uniformly over the area within the outer circumference of the support base. It may be.

【0016】

Further, the present invention includes placing an additional layer between the polishing pad and the support base. This additional layer is provided so that when the polishing pad is attracted to the support base by applying a load, an uneven portion is formed on the polishing pad. These non-flat portions help retain the polishing liquid in the polishing area of the polishing pad while polishing the substrate.

【0017】

The additional layer is preferably an elastic pad. The additional layer is perforated so that when negative pressure is applied, a portion of the polishing pad is partially drawn into the hole. Preferably, the holes have a diameter or size in the range of about 0.06 to about 0.25 inches.

【0018】

As a means for fixing the polishing pad during polishing, the polishing apparatus according to the present invention includes a nearly flat inflexible support base, a flexible polishing pad on the support base, and a polishing pad supporting base. It is provided with means for attracting to and keeping the polishing pad in a predetermined polishing position. Preferably, this attracting means comprises a vacuum source connected to at least one vacuum port on the support base, but instead of the vacuum source for attracting the polishing pad to the head, as described below. Other configurations such as may be used. In addition, the substrate carrier is movably attached to the polishing pad and support base.

【0019】

The pad may be inserted between the flexible polishing pad and the support base. Preferably, the pad is perforated or porous. More preferably, the pad is a perforated elastic pad.

【0020】

Further disclosed is a method of stabilizing the polishing medium when the substrate is pressed against the polishing medium for polishing. The method comprises providing the polishing medium over a substantially inflexible support surface and applying a negative pressure between the support surface and the polishing medium to attract the polishing medium to the support surface. Negative pressure is applied with a force of about 0.2-3.0 psi, preferably about 1.2 psi.

【0021】

Preferably, the method further comprises pressing the substrate against the polishing medium for polishing while maintaining a negative pressure so that the polishing medium does not move relative to the support surface. The method further includes a step of pulling the substrate out of contact with the polishing medium, a step of stopping applying negative pressure, and a step of removing the polishing medium for cleaning, conditioning, or replacement. Good.

【0022】

The method may include cleaning and / or conditioning the polishing medium and then restoring the polishing medium. After returning the polishing medium to its original state, a negative pressure is applied again between the support surface and the polishing medium, and the polishing medium is attracted to the support surface. Alternatively, another polishing medium may be placed on the support surface to replace the first polishing medium. When a new polishing medium is placed, negative pressure is again applied between the other polishing medium and the support surface, and the other polishing medium is attracted to the support surface.

【0023】

Optionally, a porous layer may be provided between the polishing medium and a substantially inflexible support surface before applying negative pressure. Then, when a negative pressure is applied, a part of the polishing medium is partially drawn into the pores of the porous layer, and a dent is formed on the polishing surface of the polishing medium.

【0024】

A device for stabilizing the polished surface has been disclosed, which comprises applying a substantially inflexible support base, a flexible polishing pad that overlaps at least a portion of the support base, and a substrate onto the polishing pad. Includes a carrier that polishes the substrate. Means for keeping the polishing medium substantially wrinkle-free with respect to the substrate are, for example, a vacuum port on the support base and under the polishing pad, or a flexible polishing pad carrier. And may include a mechanism for attracting to the substrate.

【0025】

If at least one vacuum port is provided on the support base, the polishing pad may be attracted to the support base and the polishing pad may be kept in place by applying negative pressure through it. .. At least one vacuum port may be formed on the carrier if the means for maintaining include a mechanism for attracting a flexible polishing pad to the carrier and substrate. A vacuum source is provided to apply negative pressure between the carrier and the polishing pad via at least one vacuum port, thereby substantially at least the portion of the polishing pad beneath the carrier and substrate at any time. It can be maintained in a wrinkle-free state.

【0026】

[Detailed Description of Embodiment]

Refer to the drawing for details. The same reference numerals indicate the same components, and the present invention generally relates to improving the polishing pad of a polishing apparatus. Understanding the basic components of a polishing machine will give a better understanding of the invention, which will become apparent below.

【0027】

With reference to FIG. 1, in general, the substrate carrier 120 is typically located above a support base 250 that supports a polishing pad or polishing strip 220. In general, the substrate carrier 120 can support the wafer or substrate and at the same time apply the force required to facilitate polishing. The substrate carrier 120 may have some ability to automatically align the substrate 260 with the plane of the support base 250. Optionally, an elastic pad 240 may be inserted between the polishing pad or polishing medium 220 and the support base 250, thereby improving polishing under certain circumstances. The substrate carrier 120 may have a spindle 270, to which the required downward and rotational forces are applied. As mentioned above, the substrate carrier 120 is preferably capable of performing self-alignment so that the substrate 260 can be aligned with the polishing medium 220. Although there are many other possibilities, the substrate carrier 120 even takes into account that the lower member 290 rotates relative to the upper member 280 around the bearing means 285. Good. The polishing liquid may be supplied from the polishing liquid nozzle 230 to the polishing medium 220 in a metered manner.

【0028】

Various relative motions may be provided between the substrate 260 and the polishing medium 220 to perform the polishing operation. For example, one form of relative motion is made by holding the support base 250 immobile with respect to the ground and moving the substrate carrier 120 in a controllable manner. The substrate carrier may be controlled by a motion control device (not shown) and can perform a controlled or programmed motion in a direction parallel to the plane of the support surface 250. Alternatively or additionally, the substrate carrier may rotate about an axis defined by the spindle 270. Movements in each direction may be programmed to occur simultaneously and are typically programmed as such.

【0029】

FIG. 2 is a plan view of a first embodiment of the present invention using the circular support base 150. A flexible polishing pad 170 overlaps the circular support base 150. An optional elastic pad (not shown) similar to the elastic pad 240 described above may be used between the flexible polishing pad 170 and the support base 150. The circular support base 150 may be rotatable, thereby generating polishing pressure on the substrate as the substrate 260 is pressed against and held against the polishing pad 170 by the substrate carrier 180. Alternatively, in order to perform a polishing operation between the substrate 260 and the polishing pad 170, the support base 150 may be held stationary and the carrier 180 may be moved. The substrate carrier 180 is preferably programmable, resulting in a linear motion, a rotational motion, or a combination of both types of motion with respect to the support base 150 and the polishing pad 170.

【0030】

Therefore, there is virtually no limitation on the polishing pattern that the carrier 180 can make relative to the support base 150 and the polishing pad 170. Yet another method of operation of the device shown in FIG. 1 is that both the carrier 180 and the support base 150 move simultaneously with respect to each other. This generally means that the carrier 180 makes a rotary motion, a linear motion, or a combination of both types of motion, and the support base 150 also makes a rotary motion.

【0031】

Also, many conventional polishing devices with a rotating support base attach the polishing pad to the support base with an adhesive. Such a configuration is cumbersome to handle when it is time to replace the polishing pad due to wear or condensation. Removal of the polishing pad is not easy to perform, and some of the pad and / or adhesive may remain, making sure that the support base is extremely flat when installing a new polishing pad. Requires additional consideration to ensure. As a result, this can be a very tedious and time-consuming process, reducing production by creating downtime.

【0032】

However, as mentioned above, a common problem that arises when the pad is not secured to the polishing platen by an adhesive or other mounting means is that polishing pressure is applied from the substrate carrier to the polishing pad via the substrate. Sometimes the polishing pad moves from its predetermined position. This movement causes the frictional force between the substrate and the polishing pad, including any chemical polishing medium that may be used, to be greater than the frictional force present between the polishing pad and the support base (polishing platen). It is caused by being large.

【0033】

The configuration shown in Figure 2 not only overcomes the problems caused by adhesively attached abrasive pads, but also overcomes the problems mentioned above related to non-adhesive pads. is there. A vacuum port 190 is formed on the support base 150 and is connected to a vacuum source (not shown in FIG. 2). In the case of a rotating support base 150, the vacuum source communicates with the vacuum port via a slip ring or other equivalent device known in the art. A seal barrier 195 surrounds the vacuum port and traces the contour just inside the outer circumference of the polishing pad 170, preferably this seal barrier 195 is a strip-like seal ring made of a material such as IC1000 (commercially available from RODEL). , O-rings, or any other material that forms an effective vacuum seal. Therefore, when the polishing pad 170 is placed on the support base 150, it is depressurized through the vacuum port 190, which effectively forms a sealed state along the seal barrier 195. When the seal is formed, any air between the polishing pad 170 and the support base 150 is essentially evacuated by the vacuum source, thereby effectively fixing the polishing pad 170 to the support base 150. be able to.

【0034】

FIG. 3 shows an embodiment of a polishing apparatus in which it is practically impossible to fix the polishing pad to the support base with an adhesive, and for this reason, the present invention becomes more important in this apparatus. In this embodiment, the polishing medium magazine 350 is used instead of the individual polishing pads 170. The polishing medium magazine 350 is shown with the associated substrate carrier 354, which substrate carrier 354 may be controlled to allow any transport as described above in connection with the carrier 180 shown in FIG. Any polishing liquid delivery nozzle 352 may supply the polishing liquid to the polishing medium 310. The abrasive delivery nozzle 352 may be attached to the substrate carrier 354 and move with the substrate carrier 354 or may be arranged separately, or both configurations may be used. Good. The substrate carrier is illustrated for illustration purposes only and can be replaced with other devices such as, for example, a substrate carrier driven by a linear motor.

【0035】

The polishing medium magazine 350 preferably uses a polishing medium 310 supplied in the form of a roll of long medium. The polishing medium 310 preferably comprises a thin polymeric film substrate having either a polishing pad or a fixed abrasive that covers the polishing medium 310 with at least a partial width. The film may be about 0.001 to 0.020 inch thick, preferably about 0.005 to 0.007 inch thick. The polishing medium 310 must be substantially impermeable to the polishing liquid. Preferably, the material is made from Mylar film or polyethylene glycol terephthalate. The new polishing medium 310 is preferably automatically supplied by the polishing medium magazine 350, so that the user does not have to intervene until the entire roll is consumed.

【0036】

The polishing medium 310 may have various paths through which the polishing medium magazine passes, depending on the appropriate equipment configuration and mechanism that is desired to be placed in the middle of the path of the polishing medium. For the path, the title of the invention, "Polishing Media Magazine For Improved," Polishing) , co-pending US application No. 08 / 833,278 filed April 4, 1997, the content of which is incorporated herein by reference in its entirety. In FIG. 3, the medium is a roll delivered from the feed roll 300 under the first rotation diversion bar 320 and through the top surface 356 of the platen support 355. The polishing medium 310 passes through the top surface 356, over the second rotation conversion bar 325, through the conditioning system 305, around the third conversion bar 330, and finally to the take-up roll 340. It is rolled up. The third rotation diversion bar 330 is preferably located lower than the take-up roll 340 in the vertical direction. According to this configuration, the resulting angle 359 attempts to collect the polishing liquid on the third rotation conversion bar 330 and reliably drops it from the polishing medium 310 into the waste liquid tank 358 as shown. Can be made to.

【0037】

By supporting the tensioned portion of the polishing medium with a precisely positioned transforming bar member, the tensioned portion of the polishing medium is accurately positioned with respect to the other mechanisms of the polishing medium magazine. can do. These transforming bar members are typically elongated cylinders or rods polished into a cylinder, each end of which is supported by a bearing. These rotation-altering bars are typically used to reduce friction and abrasion throughout the system, but for example, different non-rotating members such as porous web rolls or floating rolls. It may be used to provide the desired polishing medium path. Such an example provides a completely non-contact method of transporting the medium.

【0038】

Whatever member is used to form the path of the polishing medium, the tensioned portion still completely solves the aforementioned movement and buckling problems that may occur during polishing. Not. A polishing device using a polishing medium magazine may be used in conjunction with the vacuum fixing system according to the present invention in order to more firmly fix the tensioned portion in place during polishing. The system can be attached to such equipment regardless of whether the equipment uses a slurry-type polishing medium or a slurry-less type polishing medium. The vacuum fixation system decompresses between the tensioned portion of the polishing medium and the polishing support surface, increasing the pressure at which the tensioned portion is held in place in it. As a result, the attractive force between the polishing medium and the supporting surface is greater than the frictional force between the substrate and the polishing medium, including any chemical polishing medium that can be used, causing the polishing medium to move or buckle. (buckling) does not occur at all. This type of solution is not limited to chemical mechanical polishing, but can be applied to mechanical polishing equipment as well. In addition, the pressure provided by the vacuum fixation system is such that movement and buckling are adequately prevented without the need to apply tension to the polishing medium.

【0039】

In the example shown in FIG. 3, the vacuum source 192 is connected to the vacuum port 190 through the support 355. Although not shown, a seal barrier 195 is placed around the vacuum port 190, similar to that described in connection with FIG. 2, and lying just inside the outer perimeter of the tensioned portion of the medium 310. .. The vacuum source is preferably a high capacity low pressure blower (eg, commercially available from GAST, FUJI, AMETEC) and creates a degree of vacuum in the polishing medium of about 0.2-3.0 psi. The preferred degree of vacuum applied is about 1.2 psi. If the medium used is thinner than the standard one described above, a Venturi pump may be used to create a degree of vacuum of about 3-4 psi for the medium.

【0040】

A typical operation of the apparatus shown in FIG. 3 is to index the medium 310, place a predetermined portion of the medium on the surface 356, apply tension to the predetermined portion of the medium 310 on the surface 356, and then vacuum source 192. Including applying negative pressure by. When the seal barrier forms a seal between the medium 310 and the surface 356, the negative pressure exhausts all the air present between the medium 310 and the surface 356, at which point the medium is essentially. , Fixed to surface 356. Following that, the polishing operation can be started. Preferably, the negative pressure state is maintained until a movement of the medium is required for conditioning or cleaning, or to advance a new medium portion to be used for polishing.

【0041】

FIG. 4 is a partial view of a polishing system according to another embodiment of the present invention. The polishing medium 310 passes over the roller 420, which does not affect the present invention. In this embodiment, the longitudinal edge of the support surface underneath the polishing medium 310 is lifted higher by the movable edge member 465 than the rest of the support surface. Although not mentioned above, the longitudinal edge of the surface 356 may optionally be lifted higher than the rest of the surface 356, but the edge of it was integrally molded with the rest of the surface 356. It is a thing. The medium 310 only needs to have a working area for polishing that is as large as the flat portion in the middle of the lifted edge portion. The area outside the effective width does not have to be covered, thereby saving material costs.

【0042】

The lifted edge portion helps to form the lifted edge of the polishing medium 310. In the case of embodiments where the slurry is used in the polishing process, the lifted edges help retain the slurry in the polishing area and also make the slurry suitable for either recirculation or disposal. Helps pour into a container. More importantly for the present invention, the lifted edge further presses the medium 310 against the seal barrier, ensuring that it is evacuated when negative pressure is applied to the system by the vacuum source 192. Guarantee.

【0043】

The movable edge member 465 is particularly effective for maintaining an arrangement such that the seal barrier 495 is sealed with the polishing medium 310, as shown in FIGS. 5 (a) and 5 (b). As shown in FIG. 5B, the edge member 465 is urged upward by the urging member 468 in the direction perpendicular to the support member 455. The urging member 468 is preferably a spring, most preferably a coil spring, but may be easily replaced with other springs having equivalent urging properties, such as O-rings, bladder, pneumatics. It may be replaced with other elastic urging mechanisms such as type or hydraulic devices.

【0044】

When negative pressure is applied through the vacuum port 190, a sealed state is formed between the medium 310 and the seal barrier 495. Then, as shown in FIG. 5A, the medium is attracted flatly to the support surface 465 by the negative pressure and fixed there. The negative pressure is sufficiently superior to the urging force of the urging member 468, and as shown in FIG. 5 (a), when the edge member 465 is pushed down to the maximum, the urging member 468 is compressed. Note that the edge members 465 are pushed down to the lowest vertical position where they sit. At their lowest position, the edge member 465 aligns with the polishing medium 310 to ensure a smooth, flat contact surface throughout the flat polishing surface 465 bordered by the edge member 465.

【0045】

At the same time that the negative pressure is released, the urging force of the urging member becomes larger than the downward force of the medium 310 as reduced as possible. As a result, the edge members 465 are urged to their highest position, as shown in FIG. 5 (b). By being in the top position, the edge member ensures that the seal barrier along the vertical edge remains in contact with the medium 310 in the absence of negative pressure, also as shown in FIG. 5 (b). To do. This again ensures that the system is evacuated when desired, which greatly improves the reliability of the system.

【0046】

The partial view of the polishing system 550 shown in FIG. 6 shows another configuration for applying negative pressure to the contact surface between the support surface 456 of the support member 455 and the polishing medium 310. In this configuration, a plurality of vacuum ports 290 are spaced apart along a surface 456 just inside the outer circumference as defined by the seal barrier 495. In the illustrated example, the vacuum ports 290 are spaced at regular intervals and have the same dimensions. However, the present invention is not limited to such. The placement of the vacuum ports may be arranged more densely, for example, along the lateral edges to compensate for the absence of lifted edges near the lateral edges. Separately or in addition, the vacuum port may have different dimensions at different positions to allow arbitrary negative pressure to be applied. Also, many small vacuum ports may be placed across the surface 456 to achieve the secondary goal of helping prevent slurry / liquid depletion, which will be described below. Explained in detail.

【0047】

FIG. 7 shows a partial view of a polishing system 650 having yet another configuration for applying negative pressure to the contact surface between the support surface 556 of the support member 555 and the polishing medium 310. In this configuration, multiple very small vacuum ports 390 up to 1/4 inch (0.25 ), preferably up to 1/8 inch (0.125 ), have an effective width of surface 556 (ie, ie). It is located under the tensioned portion of the polishing medium and throughout the area within the boundaries of the seal barrier 495). In the illustrated example, the vacuum ports 290 are arranged approximately uniformly and have approximately the same dimensions. However, the present invention is not limited to such. The arrangement of the vacuum ports may be, for example, more densely packed near the outer perimeter of the surface in the vicinity of the seal barrier 495. Separately or in addition, the vacuum port may have different dimensions at different positions to allow arbitrary negative pressure to be applied. For example, the vacuum port along the inside of the outer circumference of the seal barrier 495 may be larger than the vacuum port inside the seal barrier (the vacuum port closer to the center of the surface 556).

【0048】

All of the embodiments described above may be configured to have a lifted integrally molded longitudinal edge, a movable lifted edge member, or an edge that is coplanar with the rest of the support surface. Good.

【0049】

FIG. 8 shows a partial view of a polishing system 475 having yet another configuration for applying negative pressure to the contact surface between the support surface 478 of the support member 476 and the polishing medium 310. In this configuration, a groove or passage 477 is formed around the support surface 478, roughly surrounding it, and inside the boundary of the seal barrier 495. A vacuum source (not shown, similar to that described in connection with FIG. 3) is connected to passage 477 via a vacuum port 479 penetrating support 476.

【0050】

When negative pressure is applied, the air existing between the polishing medium 310 and the portion of the polishing surface 478 inside the seal barrier 495 is exhausted through the passage 477 and the port 479, thereby polishing the polishing medium 310. It attracts to surface 478 and holds the polishing medium firmly in place during the polishing process. In the illustrated example, passage 477 has substantially uniform dimensions over its entire circumference. However, the present invention is not limited to such, even if the passages are formed to be thicker or deeper in selected areas such as the corners or edges of the rectangular pattern shown. Good. Also, the passages may be formed in other patterns such as oval, drum-shaped, and the like.

【0051】

FIG. 9 shows a further transformation that can be performed using the vacuum passage. In this embodiment, an additional passage 487 is formed inside the outer circumference defined by the passage 477. The two passages 477 and 487 are connected by a connection port 488 below the polished surface 489. Alternatively, passages for connecting passages 477 and 487 may be formed on the polished surface 489, but port 488 is more preferred. Since the passage 487 is generally located in the polished area, it is not always the case, but it is preferable to form the passage 487 so that it is thinner than the passage 477, and as a result, the flatness of the polished surface is almost non-existent. Not disturbed. Port 491 connects passage 477, passage 487, and port 488 to a vacuum source (not shown).

【0052】

All of the embodiments described above are configured to have a lifted integrally molded longitudinal edge, a movable lifted edge member, or an edge that is coplanar with the rest of the support surface. May be good.

【0053】

FIG. 10 is a cut-out view of the structure of the polishing device, which also polishes chemical liquids or slurries, or other liquids used between the substrate to be polished and the polishing pad. It was designed to solve the problem of exhaustion inside. As mentioned above, after some polishing operation, the liquid tends to be consumed more and more, and finally the liquid almost completely disappears between the substrate and the polishing pad. It ends up. Due to the relatively smooth and flat surface that makes up the surface of the polishing pad / platen and the substrate to be polished, the polishing operation tends to "sweep out" chemical liquids / slurries with the surface of the substrate to be polished. A vacuum state or negative pressure gradually increases between the polishing pad and the polishing pad.

【0054】

The polishing apparatus 750 includes a porous elastic layer 710 between the polishing medium 310 and the support surface 556. When negative pressure is applied through the vacuum port 190, the polishing medium 310 is pressed against the support surface 556 with sufficient force to compress the elastic layer 710 at least partially. The thin polishing medium is further attracted to the elastic layer 710 as air is removed from the holes and partially enters the holes 720 of the elastic layer 710. As a result, a plurality of recesses or "dents" are formed on the polished surface of the polishing medium 310. FIG. 11 shows a partial cross-sectional view illustrating the relationship between the support 555, the elastic layer 710, the polishing medium 310, and the substrate 260.

【0055】

The recess 810 of the polishing medium 310 is formed on the hole 720 of the elastic layer 710 when a negative pressure is applied as described above. The recess acts as a capacitance to store slurry, KOH, water, or any liquid medium 840 used in the polishing process. Therefore, even when the extremely flat substrate 260 passes over the polishing medium 310, not all of the liquid 840 is swept out of the polishing area. That is, a mass of fluid / polishing medium remains in the dent 810 to prevent slip / sticking (eg, "stiction") problems often caused by a lack of slurry / liquid under the substrate to be polished. Help to do.

【0056】

A preferred elastic layer is the IC1000 pad commercially available from RODEL, but can be replaced by other equivalent porous and elastic materials commercially available. Alternatively, a relatively inelastic layer with holes similar to IC1000 may be successfully used to form dents in the polishing medium 310. Furthermore, when the support surface 556 includes a vacuum port 390 having a size close to the hole of the IC 1000 such as the vacuum port shown in FIG. 7, the layer between the polishing medium 310 and the support surface 555 is completely omitted. If so, the dents may be formed in the polishing medium 310.

【0057】

FIG. 12 is a partial view of a polishing system according to another embodiment of the present invention. In the embodiment described above, the polishing medium 310 passes over the rollers 420 and 325, which, as in the embodiment described above, is not important to the present invention. This is because the present invention may be implemented by another medium configuration, for example, a polishing medium consisting of a flexible single sheet. In this embodiment, the support surface 856 of the support member 855 is recessed, or at least recessed, in its central portion 857 (see also FIG. 13).

【0058】

The edge surface 858 supports the polishing medium 310, the polishing medium is preferably tensioned on the surface 855, with or without negative pressure applied to the edges of the polishing medium (preferably negative pressure). Is fixed to the edge surface 858 by the clamp 870). The medium is preferably tensioned with a force of at least 2 lbf per inch of medium. Preferably, the media fixation is done near the four corners of the table with four clamps 870, as shown, but more clamps may be used or fewer clamps are used. May be done. Alternatively, the medium may be clamped across the edges on either side of it using a long clamp, the surface of which long clamp has a foam material or other soft taper lying beneath it. The material is applied.

【0059】

The substrate carrier 860 preferably comprises at least one vacuum port 865 in an area surrounded by a containment ring 868 or other structural member outside the substrate 260. Vacuum port 865 is connected to vacuum source 880 via vacuum tube 890. As with the embodiment described above, this embodiment is not limited to using one vacuum port, another configuration is arranged at various intervals along the perimeter of the ring region. It may include multiple vacuum ports of equal or unequal dimensions. When a large number of vacuum ports are used, preferably the vacuum ports are arranged at equal intervals around the ring region, but this is also not necessarily the case.

【0060】

At least one seal barrier 866 is provided along the perimeter of the substrate carrier 860, preferably very close to the edge of the carrier 860 and, of course, surrounding one or more vacuum ports 865. Will be done. The surface of the accommodating ring 868 in contact with the polishing medium 310 preferably acts as a seal barrier 866. Optionally, a dedicated seal barrier may be placed on the containment ring 868 in contact with the surface or adjacent to the inside of the circumference of the containment ring 868. When negative pressure is applied through the vacuum port 865, a sealed state is formed between the medium 310 and the seal barrier 866. The medium is then flatly attracted to the bottom surfaces of the substrate 260 and the substrate carrier 860 and fixed there by the negative pressure drawn into the vacuum through the vacuum port 865.

【0061】

Subsequent polishing of the substrate may be subsequently initiated. The force exerted on the substrate 260 by the substrate carrier 860 acts in the opposite direction of the negative pressure that attracts the medium 310 to the surface of the substrate 260 to be polished, thereby the machining pressure required to polish the substrate (ie). , The "P" variable of Preston's equation). One advantage of this configuration is that it does not require a perfectly flat flat polished or supporting surface. In addition, the weight of the support member 855 can be much lighter due to the central portion having indentations or dents that may not be able to provide a support that is pressed against it and polished.

【0062】

When the negative pressure is released, the urging force of the tensioned medium 310 becomes greater than any attractive force that may still be present between the medium 310, the substrate 260, and the carrier 860. As a result, the medium 310 retracts from contact with the substrate 260 and the substrate carrier 860 to restore a substantially flat shape that is coplanar with the support 855. An optional mechanism is provided to provide positive pressure, such as positive fluid pressure (preferably air), to the medium 310 after releasing the negative pressure to help the medium 310 separate from the substrate 260 and the carrier 860. , May be provided to carrier 860.

【0063】

The carrier 860 is then lifted from the medium 310 and the substrate can be easily removed for inspection and / or replacement. When the new substrate is placed between the medium 310 and the carrier 860, the carrier 860 is repositioned in the vicinity of the medium 310 or in contact with the medium 310. By applying the negative pressure again, the sealing state as described above is generated, and at that point, polishing is restarted.

【0064】

FIG. 14 is a cross-sectional view of a system using the vacuum technique as described above in connection with FIGS. 12 and 13. Also shown are embodiments of the substrate carrier 860. The plate 955 of the substrate carrier 860 constitutes an upper reference plane, from which the pressurizing means 960 loads the substrate 260. In this example, the pressurizing means includes three concentric rings 961, 962, and 963 configured to control the flow rate and release gas and / or liquid. Preferably, the pressurizing means 961, 962, and 963 release air so as to form a layer 970 of pressurized air between the plate 955 and the substrate 260. However, other gases, water, mixtures of water with air and / or other gases, or negative pressures are used to form a support or fixation layer 970 between the plate 955 and the substrate 260. May be good. Of course, this type of carrier is not limited to using three rings, and may use four or more rings, or may be one or two rings.

【0065】

In the illustrated embodiment, pressure conduits 964, 965, and 966 connect rings 961, 962, and 963, respectively, to a source of pressurized air (not shown). A throttle valve 967 is provided for each line, allowing the operator to individually control the flow rates of the rings 961, 962, and 963, using one input line 968. A more detailed and complete description of such a carrier is co-pending with agent reference number 36172-20017.00, the name of the invention "Padless Substrate Carrier", filed on the same day as this application. It is stated in the application. This application, "Padless Substrate Carrier," is incorporated herein by reference in its entirety.

【0066】

Optionally, the slurry line 972 may penetrate the drive plate 971 so that the slurry can be supplied continuously or otherwise under automatic control to the system using the slurry with the polishing medium. .. The present invention is not limited to the use of the carriers described in FIG. 14, but uses more general carriers, including carriers with pads lined with a substrate, rotating carriers, and the like. You may. Various designs may be used, such as a compatible crown with an air bag and a design with other pressure devices to fit the carrier crown.

【0067】

In the embodiment of FIG. 14, the flow rates of rings 961, 962, and 963 may be adjusted to deliver air / liquid at equal flow rates / pressures or at a constant pressure distribution, or. Both may occur at the same time. Further, the outermost ring 961 may be formed very close to the edge of the face plate 955 so that the pressure wave can spread near the edge of the face plate 955 at a substantially constant value. The support layer 970 further allows the substrate to "swing" or precess with respect to the face plate 955. This is because the face plate 955 does not come into contact with the back side of the substrate once the layer 970 is formed. The radius of the substrate 260 is somewhat smaller than the radius of the face plate, and the substrate is held in place between the face plate 955 and the polishing medium 310 by the presence of the accommodating ring 868.

【0068】

Consistent material from edge to center of the board by combining the ability to apply load pressure to the entire back surface of the board almost uniformly with the ability to allow the board to precess or swing within the containment ring. An extremely uniform polishing process can be obtained.

【0069】

Alternatively, in situations where the pressure distribution must be embodied or adapted, the flow rates of the rings 961, 962, and 963 may be varied to achieve the desired pressure distribution structure.

【0070】

According to the apparatus of FIG. 14, during polishing, as described above, not only the pressure is applied by the carrier applicator 960, but also the negative pressure applied to the polishing medium in the carrier 860 via the vacuum tube 890 is applied to the substrate. Atmospheric pressure P that attracts the polishing medium 310 to the 260 and presses the polishing medium 310 against the back side of the substrate 260 with uniform pressure._aThe pressure of the polishing medium 310 is held there in place, while the back surface of the substrate 260 is subjected to the pressure of the liquid / air supplied by the carrier 860, or, for example, through a highly porous sheet. Is supported by suction to the carrier.

【0071】

Conveniently, according to this configuration, the carrier 860 does not need to apply a vertical force to the support 856. Therefore, the drive plate 971 only needs to provide a horizontal force during polishing. Moreover, a highly accurate polished surface is not required. This is because the actual polishing operation is performed without contacting the support 856, and the polishing medium 310 is pressed against the polishing surface of the substrate 260. This not only significantly reduces the weight of the polishing apparatus, but also significantly reduces the cost of the support 856. In addition, the support 856 can be manufactured much smaller and lighter, which makes it much easier to stack and assemble multiple units or modules for parallel processing of substrates. Such modules are such that the polished surfaces of the horizontally arranged wafers are oriented upwards and downwards, or the polished surfaces of the wafers are arranged vertically or deviate from the horizontal in various ways. They may be stacked or arranged so that they are arranged.

【0072】

An optional further form of the carrier 860 is to provide a face plate 955 made of a transparent material such as polycarbonate, the surface of which comprises an electrostatic film. By providing the transparent face plate 955, the observer can confirm that the substrate is properly processed during polishing.

【0073】

FIG. 15 is a cross-sectional view of a further preferred embodiment of the substrate carrier 1060, which not only uses negative pressure to control the pressing of the substrate by the carrier plate, but also uses the substrate as a carrier. Negative pressure is also used to provide a fixed pressure for holding. In this configuration, the carrier plate 1155 is attached to the carrier loading column 1110 via a seal plate 1120 and a carrier plate descent stop 1172 extending from the containment ring support 1170. A diaphragm 1140 is mounted between the seal plate 1120 and the carrier plate 1155 to form a pressurable chamber 1145.

【0074】

The arrangement of the carrier loading column 1110 forms a base for arranging the entire carrier. The placement of the carrier loading column 1110 primarily controls the load on the containment ring 1180, which controls the lateral bearing capacity of the substrate during polishing.

【0075】

The vacuum source 1130 is connected to the second pressurable chamber 1134 via the main vacuum tube 1132 connected to the vacuum holes 1147 of the containment ring support 1170. Negative pressure / positive that the vacuum wafer pickup holes 1182 in the carrier plate 1155 can be individually controlled via a manifold 1184 connected to at least one vacuum port 1166 by vacuum piping and fixtures (not shown). Connected to a pressure source (not shown). By applying negative pressure through the vacuum holes 1182, the back side of the substrate is fixed to the carrier plate 1155. In this example, in addition to a vacuum hole centered through the surface 1155'of the carrier plate 1155, four rings of the vacuum hole are provided, but another vacuum hole configuration replaces it. May be used as. In addition, monitoring holes 1192 may be provided in the middle of the array of vacuum holes 1182 for use in monitoring pressure and / or flow rates where they are located. The monitoring holes may be individually connected to individual pressure / flow rate monitoring sensors (not shown) via the manifold 1194, or may be connected to a central sensing unit (not shown).

【0076】

A unique tube 1160 connects to the pressurizing chamber 1145, and the opposite end of the tube 1160 is provided with an orifice 1162 exposed to atmospheric pressure. Valve 1164, which is preferably a bleed valve, connects the main tube 1132 and a different tube 1160 to each other. The valve 1164 can be adjusted to stop the flow from the unique vacuum tube 1160 to the vacuum source 1130, in which case the pressurizing chamber 1145 is at atmospheric pressure through the orifice 1162. .. This relatively high pressure inflates the pressurizing chamber and pushes the diaphragm 1148, thereby pushing the carrier plate 1155 and surface 1155'downward in FIG. 15, which effectively applies greater polishing pressure to the substrate. Add to. The carrier plate descent stop 1172 prevents the carrier surface 1155'from being excessively pushed down in the downward direction by limiting the downward movement of the carrier plate 1155.

【0077】

The valve 1164 can be tuned to facilitate the flow from the unique vacuum tube 1160 to the vacuum source 1130 and to variably regulate the flow rate, in this case the addition. The pressure chamber 1145 has a pressure value below atmospheric pressure. This causes the pressurization chamber to contract and attract the diaphragm 1148, thereby pushing the carrier plate 1155 upwards in FIG. 15, which effectively applies less polishing pressure to the substrate. As mentioned above, the degree of upward motion can be controlled by adjusting valve 1164 to change the flow rate.

【0078】

Similar to the configuration of FIG. 14, according to this configuration, a negative pressure is applied to the polishing medium during polishing, attracting the polishing medium 310 to the substrate 260, and applying the polishing medium 310 to the substrate 260 at uniform pressure. Atmospheric pressure P pressed against the back side_aThe polishing medium 310 is held in place by the pressure of, and at the same time, the back surface of the substrate 260 is held by the negative pressure applied via the carrier face plate 1155'as described above.

【0079】

The same advantages described in relation to the embodiment shown in FIG. 14 are obtained for this embodiment as well. To control the wear of the substrate and the heat generated as a result of the frictional force between the substrate and the polishing medium, a sprayer or air injector is used to make direct contact with the backside of the polishing medium 310, i.e. the substrate. One or more cooling streams may be sprayed on the non-side. Alternatively, the water bed may be provided in contact with the back side of the polishing medium 310.

【0080】

Also preferably, a harder backing material is provided on the polishing medium 310 by attracting a thin polycarbonate sheet (eg, about 0.060 inch thick) to the backside of the medium under negative pressure. Alternatively, the strength may be enhanced by simply increasing the thickness of the polishing medium itself. In addition to, or in place of it, the sheet of backing material may be grooved on the side of the polishing medium in contact with the backside to improve the uniformity and flatness of the substrate.

【0081】

[Example]

1. The polished support surface comprises a substantially rectangular seal barrier with dimensions of approximately 22 × 19 . One vacuum port is provided in the center of one end of the polished surface defined within the outer circumference of the seal barrier. By applying a negative pressure of about 2 psig, an area of about 418 square inches provides about 836 lbs of gravitational pull on the polishing medium overlaid on the support surface, which forms a vacuum sealed state by the seal barrier. This additional load may be used to eliminate elongation, movement, buckling of the polishing medium and to eliminate the need to apply tension to the polishing medium. The polishing medium is a MYLAR film with a fixed abrasive in its polishing area, which is commercially available from 3M (3M) or DuPont.

【0082】

2. In addition to the same conditions as in 1. above, the IC1000 layer is placed as a sub-pad under the polishing medium and above the support surface. When negative pressure is applied through the vacuum port, the polished area of the polishing medium is pressed against the subpad and support surface. Air is deprived of the space between the polishing medium, the subpad, and the support surface, compressing the subpad, and also allowing the portion of the polishing medium above the hole in the subpad to partially penetrate the hole. When the mixture of KOH and water is supplied to the polished surface of the polishing medium, the polishing operation is started. Wafer carriers, wafer holding rings, and wafer motion with respect to the polishing medium tend to sweep the polishing solution of KOH / water out of the polishing area.

【0083】

However, the dents in the polishing medium formed by the portion above the holes in the subpad of the polishing medium partially entering the holes in the subpad due to negative pressure catch a small pool of polishing liquid consisting of KOH / water, which catches it. The surface of the wafer to be polished can constantly obtain a polishing solution.

[Simple explanation of drawings]

[Figure 1]

It is a partial cross-sectional view which shows the Example of the polishing apparatus and the basic component thereof.

[Figure 2]

It is a top view which shows the 1st Example of this invention using a circular support base.

[Fig. 3]

It is a schematic block diagram of the polishing apparatus which used the polishing medium magazine.

[Fig. 4]

FIG. 3 is a partial isometric view of a polishing system according to another embodiment of the invention in which a polishing medium magazine is used.

[Fig. 5]

(a) is a cross-sectional view along the line segment 5-5 when the negative pressure of the device shown in FIG. 4 is applied, and (b) is the line segment 5 when the negative pressure of the device shown in FIG. 4 is not applied. It is a cross-sectional view along -5.

[Fig. 6]

It is a partial view which shows the deformation of the system shown in FIG.

[Fig. 7]

It is a partial view of the polishing system which has a further deformation in the structure for applying a negative pressure to the contact surface between a support member and a polishing medium.

[Fig. 8]

FIG. 5 is a partial view of a polishing system having yet another modification in the configuration for applying negative pressure to the contact surface between the support member and the polishing medium.

[Fig. 9]

It is a partial view of the polishing system with the deformation of FIG. 8 in the configuration for applying a negative pressure to the contact surface between the support member and the polishing medium.

[Fig. 10]

It is a cut-out view of the structure of the polishing apparatus which was made to solve the problem that the polishing liquid was depleted during polishing.

[Fig. 11]

It is a partial cross-sectional view explaining that a dent is formed on the polished surface of a polishing medium.

[Fig. 12]

It is a partial perspective view of the polishing system according to another embodiment of the present invention.

[Fig. 13]

It is a figure which shows the support member used in the embodiment of FIG.

[Fig. 14]

It is sectional drawing of the apparatus using the principle of the system shown in FIG.

[Fig. 15]

FIG. 12 is a cross-sectional view of another embodiment of the substrate carrier used when using the principles of the system shown in FIG.