Planar magnetron sputtering method

[Detailed Description of the Invention]

[Application of the Invention] The present invention relates to the planar magnetron sputtering method for changing the path of annular plasma and forming a synthetic thin film. [Background of the Invention] For [ which is called the Cospatta method to high melting point metal Thilly Said's sputtering membrane formation ] high melting point metal simple substances, The method of forming the mixed film of a high melting point metal and silicon on the wafer (substrate) which installed a plurality of sputtering electrodes for silicon simple substances in the same chamber, dispersed a high melting point metal and silicon simultaneously from these electrodes, and was attached to the rotating jig is common. It is because the alloy of a high melting point metal and silicon has the very high melting point (generally more than 2000 degreeC), it is difficult to refine to carry out sputtering of a high melting point metal and the silicon with a separate electrode and the thing of purity high enough is not obtained specially. On the other hand, the above-mentioned Cospatta method attaches a wafer to the rotation vapor deposition jig which self-revolves around the sun, in order to obtain the uniform composition ratio of the high melting point metal on a wafer, and silicon. It is loaded with several many wafers on this rotating jig. the Cospatta method -- many -- in order to process several wafers collectively, it can say that there are few problems in respect of productivity, but there is a fault which the membrane formation speed which one one-sheet wafer experiences is influence of the residual gas under membrane formation small, and cannot obtain a quality film. By a next process, the mixed film of the high melting point metal and silicon which were generally created by the sputtering method anneals (Annealing), and it alloys it. As compared with the film which created the alloyed film on the conditions that membrane formation speed is high, with the film with a slow membrane formation speed although resistance decreased greatly as compared with immediately after membrane formation, resistance is size also after Annealing. As stated above, in order to solve the fault which the Cospatta method currently generally performed has, invention-in-this-application persons invented the method of alloy membrane formation by which the membrane formation speed of 10 times or more of the conventional Cospatta method is obtained. (Japanese Patent Application No. No. 113660 [ 56 to ], Japanese Patent Application No. No. 81457 [ 57 to ]) In this sputtering method, it is indicated in Drawing 1 as a planar magnetron electrode with the magnetic field generating means by electromagnetic coil 104,105 wound around the two-fold Like same mind shown in Drawing 1 in a section. In Drawing 2, sputtering target structure 201 which allocated the target member of high melting point metal 203 of the shape of a Like multiplex ring shown with the top view and silicon 202,204 in the shape of a same mind multiplex ring is used. Operation of the sputtering electrode of double magnetic pole structure is indicated in detail to JP,57-126969,A, JP,58-3975,A, and JP,58-3976,A. As for 103, the anode and 106 are iron core magnetic poles the negative pole and 102. In this sputtering electrode, it is arbitrarily changeable by adjusting the current which passes the path of the occurring annular glow discharge (plasma) on two electromagnets (coil) from terminal 104,105. Sputtering of the target member 202 of outside silicon is first carried out by making the diameter of annular plasma large. Subsequently, the path of annular plasma is made small, and sputtering of the target member 203 consisting of a high melting point metal is carried out, it ranks next, the diameter of annular plasma is further made small, and sputtering of the target member 204 of central disc-like silicon is carried out. The diameter of annular plasma is enlarged one by one again, and sputtering is performed in order of high melting point metal 203 and outermost silicon target member 202. The above is made into 1 cycle, 10 cycles of several cycle~number sputtering is wound and Return(ed), and the mixed film of a high melting point metal and silicon is made to deposit on substrate 110. Under the present circumstances, change of the diameter of annular plasma carries out, and it controls the thickness distribution on Elephants and wafer (substrate) 110, and distribution of composition for a way to expected within the limits. Target structure object 201 shown in Drawings 1 and 2 is line intermediary To have about attachment of a target member, without using annular control board 101 for the outermost circumference as a control jig, and fixing each target member itself to a backing plate especially. The feature of this people method is a point which excessive parts for fixation except a target member, etc. have not exposed to a field which receives sputtering of a target structure object. It is suitable for formation of a high purity film. For details, please refer to invention-in-this-application persons' invention Japanese Patent Application No. 58-7261. The problem in the target structure shown in Drawings 1 and 2 is mainly the following two points. It is the temperature of a target member rising, if sputtering's is actually performed to the 1st, and producing a crack in outside annular silicon target member 202 by the difference in the coefficient of thermal expansion between each target member, etc. According to an artificer's experiment, about 1000 W is a maximum of sputtering electric power, and it is Oh. Although a part for 1000A/was obtained as an average membrane formation speed at this time, and also in order to increase productivity, improvement in much more membrane formation speed is required. It is that sputtering happens also on the boundary between the target members made by a different substance as the 2nd point. The figure which enlarged the section of this boundary part is shown in Drawing 3. When it sees thinly, it is on the both sides of a high melting point metal target part with annular small step 301,302 by the difference in the thickness of each target member, and the difference in taper shape. since annular plasma has a certain amount of spread when annular plasma is on this high melting point metal -- also Absolutely(ing) -- sputtering not only of a high melting point metal but surrounding silicon is carried out. Under the present circumstances, in small step 301,302 shown in Drawing 3, electric field concentration occurs and, occasionally abnormal discharge occurs. The abnormal discharge in sputtering is considered to be small arc discharge, for example. Some target materials may adhere on the lump of the diameter of 0.1~100 micrometer, and an intermediary board by this abnormal discharge, i.e., local excessive electric discharge. This lump is called a splatter or a splash. If such a foreign substance adheres on a substrate, as a product, it will become inferior goods. It may be emphasized and the level difference structure shown in Drawing 3 will pose the problem that the point above-mentioned also at this point is big, if a target material is exhausted by sputtering. In the example shown in Drawings 1 thru/or 3, when the foreign substance considered to originate in the above-mentioned abnormal discharge formed the high melting point metal Thilly Said film of 3000A on a wafer 100 mm in diameter, about 50~200 pieces existed, and it was thought that it was difficult to apply to production. [Objects of the Invention] The object of the present invention solves the fault of the above-mentioned conventional technology, and it is a high speed more, and is in moreover adhesion of the foreign substance to the substrate top for membrane formation by abnormal discharge essentially providing the suitable planar magnetron sputtering method for sputtering of few thin films, especially an alloy thin film. [Summary of the Invention] In the planar magnetron sputtering method of the present invention generating a Ark-like magnetic field to achieve the above objects on the target installed on the electrode, and performing sputtering, A plurality of target members are installed side by side on the above-mentioned electrode so that one side may be projected to another side, It is the planar magnetron sputtering method carrying out direction of an electric field and direction of a magnetic field to parallel mostly in the boundary side between the projected target members, deterring electric discharge [ near / the / the boundary ], and carrying out sputtering in the principal surface of each target member. That is, there is the present invention in making parallel mostly the direction of an electric field, and the direction of a magnetic field in the boundary side, deterring generating of electric discharge [ near / the / the boundary ], and having been made to perform sputtering in the principal surface of each target by changing mutually the height of the principal surface of a plurality of target members. [Application of the Invention] The present invention relates to the sputtering target used as the material of the thin film formation by sputtering, is especially high purity and relates to a sputtering target with little generating of a foreign substance on the occasion of sputtering. [Example] hereinafter, a figure -- therefore, the example concerning the present invention is described. Drawing 4 is a conceptual explanatory view explaining the magnetic field distribution on target board 401 when the usual planar magnetron sputtering electrode is used, and the place of the field [ exhausting ] of a target board. The strong electric discharge called magnetron discharge to the place which becomes parallel to the field where a magnetic field vector receives sputtering of a target board sets, and as shown all over the 4th figure, electric discharge Grow becomes annular as known well. Sputtering of the target material which is directly under this annular plasma 402 is carried out. The annular field which receives this sputtering is usually called field [ exhausting ] 403 of a target, or yellow Jon field 403. A part of particles by which sputtering was carried out in the field [ exhausting ] of the target although material consumed are conversely deposited on central part 501 of the target board, or the outside 502 of an annular yellow Jon field, as shown in Drawing 5. The dashed line in a figure shows the outside of the target before use. As stated above, sputtering of the field where a magnetic field vector is parallel to a target side is carried out, but electric discharge strong against the field to which it is because the electric field vector has entered perpendicularly as shown in a target all over the 4th figure, and a magnetic field vector and an electric field vector intersect perpendicularly if it puts in another way produces this. Drawing 6 shows the situation of the electric discharge at the time of It was in which target 401' has not a perfect plane but a ring shape convex part. According to an artificer's experiment, as for annular plasma 402 described in Drawing 4, as shown in Drawing 6, the exception withered to three annular plasma 601,602,603. Of course, it is although annular plasma does not seem to have dissociated clearly in observation by viewing for the strong Grow light, As shown in Drawing 7 in detail, learning of in the yellow Jon field, three annular plasma existing in it further, since the substance of 401' has accumulated on side 701,702 of a convex part, those with three-place 611,612,613 and was able to be carried out. Thus, why a yellow Jon field annular [ three-fold ] is formed can be considered as follows. First, the electric field distribution on target 401' with a convex part is shown. 7th [ The ] figure middle point line shows an electric field vector, and the solid line shows the magnetic field vector. Now, if a target material is a conductive thing like metal, an electric flux line will enter perpendicularly to the surface of a target material. Therefore, the Such an electric field distribution shown in Drawing 7 with a dashed line is formed. On the other hand, a magnetic field vector serves as distribution shown as a solid line as well as Drawing 4, unless target material 401' is magnetic material. On yellow Jon field 611,612,613, it turns out that the magnetic field vector and the electric field vector lie at right angles mostly, and a yellow Jon field is formed. On the other hand, in side 701,702 of a convex part, it is expected that parallel, an intermediary cage, and strong electric discharge do not occur in this field mostly, and an electric field vector and a magnetic field vector can explain the audit observation about the field [ exhausting ] of the target material by experiment of the artificers who stated previously. When electric discharge actually occurs, becoming still more complicated electric field distribution is expected, but he can understand the above-mentioned experimental result qualitatively. many ion being drawn by a relation close to the occurring plasma, and measuring a speed [ exhausting ] of yellow Jon field 612 of a convex part with other yellow Jon fields -- about 5 times -- already -- and It was. As explained above, by making target material 401' project, as shown in Drawing 7, [ near the boundary side ], magnetic field vector B and an electric field vector become almost parallel, and it can carry out electric discharge deterrence. And when the number of target materials is two, in the state to which the path of the plasma ring was made to fix may be sufficient. However, when the principal surface which makes a target material three-fold and carries out sputtering needs to be made large radially, or when the amount of sputtering of each principal surface wants to change, as shown in Drawing 8, it is good for the method to which the path of a plasma ring is changed to perform. Thus, the method to which the path of the plasma ring concerning the present invention is changed is explained based on one example shown in Drawing 8. What is changed in the path with the double magnetic pole structure which is conventional technology of annular plasma is used for the sputtering electrode body. 801 is a ring made from molybdenum. 802 is a doughnut-like silicon target member and calls it an outside silicon target member henceforth. 803 is a disc-like silicon target member, and is a main silicon target member henceforth. These target members are fixed to backing plate 103 by metal bonding. Invention-in-this-application persons are conventional technologies first, It checked that the path of annular plasma could change with change of the synthetic line of magnetic force which occurs from iron core magnetic pole 106 by changing the current sent through each electromagnet (coil) from terminal 104,105 like the case of the flat target shown in Drawing 1. That is, the mixed film of It was molybdenum and silicon which have expected composition uniformly on the substrate for membrane formation by performing sputtering was obtained, carrying out intermediary change of the diameter of annular plasma also a suitable cycle. although the difference in some is in the thickness distribution characteristic and the composition distribution characteristic -- sufficient controllability -- with, it is. Next, invention-in-this-application persons counted the number of foreign substances on elephant board 110 for a pair of films. A silicon wafer 100 mm in diameter was used for object board 110. The number of foreign substances on a wafer was measured after depositing composition ratio (silicon: molybdenum) =2:1 and film thickness 3000A. The number of foreign substances 1 micrometer or more in diameter is a level of about three ~ seven pieces, and is Oh. On the other hand, at the conventional technology explained in Drawing 1, the big improvement effect from Oh at 50~200 pieces is Oh. Thus, reduction of the large number of foreign substances is because generating of the abnormal discharge in the boundary (knot) between an outside silicon target member, and a main silicon target member and a molybdenum target member was fully deterred. [Effect of the Invention] in the planar magnetron sputtering method which carries out sputtering combining two or more target member according to the present invention as explained above Generating of the abnormal discharge in the boundary (next portion) between each target member can be controlled effectively, when performing sputtering, the number of foreign substances which adheres on the substrate for membrane formation for this abnormal discharge can be compared with the former, and can be reduced by about about 2 figures, for example, it is MoSi of 3000A.₂In the case of a film, it is 0.1 piece/cm.²It was able to be made the following foreign substance densities. It is Noodle so that semiconductor device A tip etc. of the good-quality item which was not obtained conventionally by this can be obtained.

[Brief Description of the Drawings]

Drawing 1 is a figure showing the section structure of a sputtering electrode with the sputtering target structure which is conventional technology, It is a section construction drawing showing the boundary between the target members of the sputtering target which showed Drawing 2 in the upper surface figure of the sputtering target of Drawing 1, and showed Drawing 3 in Drawing 1, Drawing 4 is a conceptual explanatory view of the magnetron sputtering for explaining the generating position of a plasma ring, Section structure of a sputtering target structure where the figure showing the field [ exhausting ] by sputtering [ in /, in Drawing 5 / Drawing 4 ] and Drawing 6 show the principle of the present invention, The conceptual explanatory view showing a field [ exhausting ] by sputtering, the conceptual explanatory view in which Drawing 7 shows at Electric field and magnetic field distribution in Drawing 6, and Drawing 8 are section construction drawings of the sputtering target structure which is an example of the present invention. 101 ... sputtering target ferrule, 102 ... anode, 103 ... backing plate, 104,105 ... electromagnetic coil, 106 ... yoke for magnetic field generating, 201 ... sputtering target structure, 110 ... substrate for membrane formation, 301,302 ... boundary between target members, 403 ... field [ exhausting ], 601,602,603 ... plasma ring, 611,612,613 ... a field [ exhausting ] and 701,702 ... a target member wall surface and 801 ... an annular high melting point metal target member and 802,803 ... a silicon target member and ... a magnetic field vector and ... an electric field vector.