Method for the simultaneous double-sided material removal processing of a plurality of semiconductor wafers
A device for double-sided processing of flat workpieces has upper and lower working discs forming between them a working gap containing a carrier disc with cutout(s) for workpiece(s), the carrier disc having circumferential teeth by means of which it rolls on an inner and an outer gear wheel or pin ring, wherein the gear wheels or pin rings have a multiplicity of gear or pin arrangements which engage the teeth of the carrier discs during rolling, at least one of the pin arrangements having a guide which delimits movement of the margin of the carrier disc in at least one axial direction, the guide formed by a circumferential shoulder or a circumferential groove.
1. A method for the simultaneous double-sided material removal processing of a plurality of semiconductor wafers, comprising
abrading front and rear surfaces of the semiconductor wafers, each semiconductor wafer lying freely mobile in a recess in one of a plurality of carrier disks positioned in a working gap delineated by lower and upper annular working layers of respective lower and upper annular working disks, each working disk having at least one outer annular peripheral portion or inner annular peripheral portion extending beyond edges of the annular working layers, the inner and outer peripheral annular portions free of a working layer;
rotating the plurality of carrier disks between an annular outer gear wheel and an inner drive wheel such that semiconductor wafers lying in the plurality of carrier disks traverse a cycloidal path which causes a portion of the carrier disks and optionally also a portion of each of the semiconductor wafers to temporarily exit the working gap; and guiding the carrier disks in a movement plane which extends essentially coplanar relative to a midplane of the working gap by limiting axial movement of the portion of the carrier disk which has temporarily left the working gap, by contact of the portion of the carrier disk which has temporarily left the working gap with the outer annular peripheral portion of the working disk and/or the inner annular peripheral portion of the working disk.
2. The method of claim 1 , wherein each of the lower and upper disks further comprise a working layer carrier between the working layer and the respective lower and upper working disks, each working layer carrier extending into or beyond the outer annular peripheral portion of the respective working disk and/or the annular inner peripheral portion of the respective working disk, the working layer carrier in the outer annular peripheral portion of the working disk and/or the inner annular peripheral portion of the working disk limiting axial movement of the portion of the carrier disk which has temporarily left the working gap by contact of the portion of the carrier disk which has temporarily left the working gap with the annular outer peripheral portion and/or the inner annular peripheral portion.
3. The method of claim 1 , wherein guiding is effected by mounting guide rings on at least one of the outer annular peripheral portions of each working disk or the inner annular peripheral portions of each working disk, the guide rings optionally extending beyond an outermost edge of each working disk, the guide rings limiting axial movement of the portion of the carrier disk which temporarily leaves the working gap, the guide rings bearing no working layer.
4. The method of claim 3 , wherein each working disk comprises a guide ring on the outer annular peripheral portion of the working disk and a guide ring on the inner annular peripheral portion of the working disk.
5. The method of claim 4 , wherein both guide rings have the same ring width.
6. The method of claim 3 , wherein each working layer has a working layer carrier positioned between the working layer and the working disk.
7. The method of claim 6 , wherein the working layer carrier extends beyond the working layer.
8. The method of claim 6 , wherein guide rings are mounted outside an outer edge of each working layer and guide rings are mounted inside an inner edge of each working layer.
9. The method of claim 3 , wherein a guide ring having an inner diameter is mounted on each working disk, and the inner diameter is equal to or greater than an outer diameter of the working layer on each working disk.
10. The method of claim 3 , wherein a guide ring having an outer diameter is mounted on each working disk, and the outer diameter is equal to or less than an inner diameter of the working layer.
11. The method of claim 3 , wherein a guide ring having an inner diameter is mounted on each working disk, and the inner diameter is equal to or greater than an outer diameter of the working layer, and wherein a guide ring having an outer diameter is mounted on each working disk, and the outer diameter is equal to or less than an inner diameter of the working layer.
12. The method of claim 1 , wherein the material removal processing comprises double-sided grinding of the semiconductor wafers and each working disk comprises a working layer of abrasive material.
13. The method of claim 1 , wherein the material removal processing comprises double-sided polishing while supplying a dispersion, which contains silica sol, each working disk comprising a polishing pad as a working layer.