Grinding device and method for achieving precision of grinding device surface plate

Abstract

To provide a grinding device and a method for achieving precision of grinding device surface plate, which can easily dress the grinding wheel surface plate and maintain high grinding precision.SOLUTION: A grinding device 1 for grinding a semiconductor crystal wafer W includes wafer holding means 4 for holding the wafer W, a grinding stone surface plate 7 facing the surface to be ground of the wafer W supported by the wafer holding means 4, a base surface plate 5 having a mounting surface 9 for mounting the grinding stone surface plate 7 and supporting the grinding stone surface plate 7, a center disk 6 provided in the center of the base surface plate 5 and protruding from the mounting surface 9, and dressing means 3 facing the grinding stone surface plate 7. The center disk 6 is detachably inserted into a center hole 10 formed in the center of the base surface plate 5. The mounting surface 9 of the base surface plate 5 is dressed by the dressing means 3 with the center disk 6 not protruding from the mounting surface 9.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a grinding apparatus for grinding wafers sliced ​​from a semiconductor crystal ingot, and a method for improving the accuracy of a surface plate provided in the grinding apparatus. [Background technology]

[0002] BACKGROUND ART Conventionally, a grinding apparatus is known that grinds wafers sliced ​​from a semiconductor crystal ingot (see, for example, Patent Document 1).

[0003] This type of grinding device includes a base plate and a grinding wheel plate. The grinding wheel plate is attached to a mounting surface formed on the upper surface of the base plate. The grinding wheel plate has a grinding wheel mounted on its upper surface.

[0004] A center disk whose vertical axis coincides with the rotation axis is integrally provided in the center of the base plate. The center disk protrudes above the mounting portion of the base plate. When attaching the grinding wheel plate to the mounting surface of the base plate, the grinding wheel plate can be positioned by abutting the side edge (center side) of the grinding wheel plate against the peripheral wall of the center disk.

[0005] The surface to be ground (the lower surface in the figure) of the wafer held by the wafer holding means is brought into sliding contact with the upper surface of the grinding wheel, thereby grinding the wafer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Publication No. 2007-19434 Summary of the Invention [Problem to be solved by the invention]

[0007] In this type of grinding machine, the grinding wheel is dressed in order to maintain the grinding accuracy of the grinding wheel surface plate.

[0008] However, the mounting position of the grinding wheel surface plate is affected by the condition of the mounting surface of the base surface plate. For this reason, for example, if the mounting surface is not horizontal, dressing processing is performed to make the top surface of the grinding wheel horizontal, but the amount of grinding on the top surface of the grinding wheel during dressing processing increases.

[0009] This results in longer dressing times and an increased frequency of replacement of the grindstone surface plate, and furthermore, it becomes difficult to change the grindstone surface plate between a plurality of base surface plates, which is an inconvenience.

[0010] Therefore, it is conceivable to perform dressing processing on the mounting surface of the base surface plate using a dressing grindstone to improve the precision of the grinding wheel (for example, to make it flat and horizontal).

[0011] However, a center disc formed integrally with the base surface plate protrudes from the center of the mounting surface of the base surface plate, and the dressing grindstone interferes with this center disc, making it difficult to perform high-precision machining on the mounting surface of the base surface plate.

[0012] In view of the above, an object of the present invention is to provide a grinding apparatus and a method for adjusting the accuracy of the grinding platen of the grinding apparatus, which can easily dress the grinding wheel platen and maintain high grinding accuracy. [Means for solving the problem]

[0013] In order to achieve this object, the present invention provides a grinding apparatus for grinding wafers sliced ​​from a semiconductor crystal ingot, comprising: a wafer holding means for holding the wafer; a grinding wheel platen facing the grinding surface of the wafer supported by the wafer holding means; a base platen having an attachment surface for attaching the grinding wheel platen and supporting the grinding wheel platen; a center disk provided in the center of the base platen and protruding from the attachment surface; and a dressing means facing the grinding wheel platen, wherein the center disk is detachably inserted into a center hole formed in the center of the base platen, and the attachment surface of the base platen is dressed by the dressing means in a state in which the center disk does not protrude from the attachment surface (first invention).

[0014] According to the first aspect of the present invention, the center disk does not protrude from the mounting surface of the base plate. Therefore, when the mounting surface of the base plate is subjected to precision processing using a dressing device, interference between the dressing device and the center disk can be prevented. This ensures a highly accurate mounting surface, simplifies dressing of the grinding wheel plate, and maintains high grinding precision.

[0015] The present invention also provides a method for adjusting the accuracy of a surface plate of a grinding apparatus that grinds wafers sliced ​​from a semiconductor crystal ingot, wherein the grinding apparatus comprises wafer holding means for supporting the wafer, a grinding stone surface plate facing the surface to be ground of the wafer supported by the wafer holding means, a base surface plate having an attachment surface for attaching the grinding stone surface plate and supporting the grinding stone surface plate, a center disk detachably provided in the center of the base surface plate and protruding from the attachment surface, and a dressing means facing the grinding stone surface plate, the method comprising the steps of: a center disk retracting step of retracting the center disk to a retracted state where it does not protrude from the attachment surface of the base surface plate; and a reference surface forming step of dressing the attachment surface of the base surface plate, with the center disk retracted by the center disk retracting step, using the dressing means to form a reference surface (second invention).

[0016] According to the method of the second aspect of the present invention, first, the center disc is retracted from the mounting surface of the base surface plate in a center disc retracting step, and then, the mounting surface of the base surface plate is dressed by a dressing means in a reference surface forming step.

[0017] This allows the mounting surface to be dressed without interference between the dressing means and the center disk, ensuring a highly accurate mounting surface, facilitating dressing of the grindstone surface plate and maintaining high grinding accuracy.

[0018] In the above-mentioned second invention, if the grinding processing device is equipped with a base lower platen that overlaps the underside of the base platen when the mounting surface side of the base platen is the upper surface, prior to the center disk retraction process, a different reference surface formation process is performed in which the upper surface side of the base lower platen in a non-overlapping state is dressed using the dressing means to form another reference surface (third invention).

[0019] In the case of a grinding processing device in which a base lower platen overlaps the underside of a base platen, as in the third invention, the upper surface of the base lower platen can be further dressed using a dressing means, making it easier to achieve precision in the mounting surface of the base platen and the grinding wheel platen. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a cross-sectional explanatory view showing a schematic configuration of a grinding apparatus according to an embodiment of the present invention; [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 10 is a cross-sectional explanatory view schematically showing the configuration of a grinding apparatus according to another embodiment of the present invention. [Figure 5] FIG. 10 is an explanatory diagram showing another reference surface forming step. DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the present invention will be described with reference to the drawings. A grinding apparatus 1 of this embodiment grinds wafers W sliced ​​from a semiconductor crystal ingot, and includes a surface plate 2, a dressing head 3, and a wafer holding head 4, as shown in FIG.

[0022] The surface plate 2 includes a disk-shaped base surface plate 5, a center disk 6 provided in the center of the base surface plate 5, and a grindstone surface plate 7 supported on the upper surface of the base surface plate 5. A grinding wheel 8 is provided on the upper surface of the grindstone surface plate 7.

[0023] The upper surface of the base surface plate 5 around the center disk 6 serves as a mounting surface 9 (see FIG. 2) on which a grindstone surface plate 7 is mounted.

[0024] When attached to the base surface plate 5, the center disk 6 protrudes upward from the attachment surface 9. At this time, the position of the upper surface of the center disk 6 is lower than the position of the upper surface of the grindstone surface plate 7 attached to the attachment surface 9.

[0025] Furthermore, the center disk 6 is detachably inserted into a center hole 10 (see FIG. 2) formed in the center of the base surface plate, and is provided so as to be removable from the base surface plate 5 as required.

[0026] The dressing head 3 corresponds to the dressing means in the present invention, and holds the grinding wheel 13 via a dresser board 11 and a cup wheel 12 (see FIG. 3). The dresser board 11 is attached when dressing is performed on the upper surface of the grinding wheel 8, as shown in FIG. 1. As will be described later, the cup wheel 12 and the grinding wheel 13 are attached when dressing is performed on a mounting surface 9, which is the upper surface of the base surface plate 5, as shown in FIG.

[0027] The wafer holding head 4 corresponds to the wafer holding means in the present invention, and moves up and down while suction-holding the wafer W on its underside. The wafer holding head 4 holds the surface to be ground of the wafer W facing downward, and grinds the wafer W by bringing it into sliding contact with the grinding wheel 8 on the grinding wheel surface plate 7.

[0028] The grinding apparatus 1 having the above configuration dresses the surface plate 2 in the following manner prior to grinding the wafer W.

[0029] 2, the center disc 6 and the grindstone surface plate 7 are removed from the base surface plate 5 (center disc retraction step). As a result, the center disc 6 protruding upward from the base surface plate 5 is retracted, and the entire upper surface of the base surface plate 5 is exposed.

[0030] 3, a grinding wheel 13 is held on the dressing head 3 via a cup wheel 12, and the entire upper surface of the base surface plate 5 is dressed with the grinding wheel 13 to achieve precision (reference surface forming step). As a result, the mounting surface 9 of the base surface plate 5 can be used as a highly accurate reference surface.

[0031] Next, as shown in Figure 1, the center disk 6 is inserted into the center hole 10 of the base surface plate 5. This causes a portion of the center disk 6 to protrude from the mounting surface 9 of the base surface plate 5. Then, the grindstone surface plate 7 is set on the mounting surface 9 of the base surface plate 5. At this time, the inner end of the grindstone surface plate 7 is brought into contact with the protruding center disk 6, so that the grindstone surface plate 7 is set in a positioned state.

[0032] Subsequently, the dresser board 11 is held on the dressing head 3, and the upper surface of the grinding wheel 8 is dressed.

[0033] As a result of the above-mentioned reference surface forming process, the mounting surface 9 of the base surface plate 5 becomes a highly accurate reference surface, so that the grinding wheel surface plate 7 is mounted in a horizontal state. This reduces the amount of processing required when dressing the upper surface of the grinding wheel 8, and allows highly accurate dressing to be performed in a short time.

[0034] Thereafter, the wafer W is held by the wafer holding head 4 and brought into sliding contact with the upper surface of the grinding wheel 8, thereby grinding the wafer W.

[0035] 4, in another embodiment, in a grinding apparatus 15 having a base lower surface plate 14 overlapping the lower surface side of the base surface plate 5, first, the base surface plate 5, center disk 6, and grindstone surface plate 7 provided on the base lower surface plate 14 are all removed. As a result, the entire upper surface of the base lower surface plate 14 is exposed.

[0036] 5, a grindstone 13 is held on the dressing head 3 via a cup wheel 12, and the entire upper surface of the base lower surface plate 14 is dressed using this grindstone 13 (another reference surface forming step). This allows the upper surface of the base lower surface plate 4 to be used as another highly accurate reference surface, making it extremely easy to achieve precision for the mounting surface 9 of the base surface plate 5 and the grindstone surface plate 7. [Explanation of symbols]

[0037] W...wafer, 1, 15...grinding device, 3...dressing head (dressing means), 4...wafer holding head (wafer holding means), 5...base surface plate, 6...center disc, 7...grinding stone surface plate, 9...mounting surface, 10...center hole, 14...base lower surface plate.

Claims

1. A grinding apparatus for grinding wafers sliced ​​from a semiconductor crystal ingot, comprising: wafer holding means for holding the wafer; a grinding stone platen facing a surface to be ground of the wafer supported by the wafer holding means; a base platen having an attachment surface for attaching the grinding stone platen and supporting the grinding stone platen; a center disk provided at the center of the base platen and protruding from the attachment surface; and a dressing means facing the grinding stone platen, The center disk is detachably inserted into a center hole formed in the center of the base surface plate, a mounting surface of the base surface plate that is dressed by the dressing means in a state in which the center disk does not protrude from the mounting surface;

2. A method for adjusting the accuracy of a surface plate of a grinding apparatus that grinds wafers sliced ​​from a semiconductor crystal ingot, comprising: When the grinding device comprises a wafer holding means for supporting the wafer, a grinding stone platen facing the surface to be ground of the wafer supported by the wafer holding means, a base platen having an attachment surface for attaching the grinding stone platen and supporting the grinding stone platen, a center disk detachably provided at the center of the base platen and protruding from the attachment surface, and a dressing means facing the grinding stone platen, a center disk retracting step of placing the center disk in a retracted state where it does not protrude from the mounting surface of the base surface plate; a reference surface forming step of performing dressing processing by the dressing means on the mounting surface of the base surface plate, with the center disk retracted in the center disk retracting step, to form the mounting surface as a reference surface; A method for adjusting the accuracy of a surface plate of a grinding machine, comprising:

3. 3. The method for adjusting the accuracy of a surface plate of a grinding machine according to claim 2, When the grinding apparatus includes a base lower surface plate that overlaps the lower surface side of the base surface plate when the mounting surface side of the base surface plate is the upper surface, A method for adjusting the accuracy of a surface plate of a grinding machine, characterized in that, prior to the center disk retraction process, a second reference surface formation process is carried out in which the upper surface side of the base lower surface plate, in a non-overlapping state of the base surface plate, is dressed by the dressing means to form another reference surface.

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