IP Library › Granted Patent US 12661756
Granted Patent B2
US 12661756 · App. 18/061,058 · Granted Jun 23, 2026

Method of grinding workpiece including two grinding steps

Inventor: Makoto Saito (Tokyo, JP)
Assignee: DISCO CORPORATION
B24B49/02B24B7/228B24B7/04
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Quick Facts
Patent No.
US 12661756
App. No.
18/061,058
Granted
Jun 23, 2026
Kind
B2
Abstract

A workpiece to be ground by a grinding wheel of a grinding apparatus has a first layer including a first material and a second layer including a second material that is harder to grind than the first material and stacked on the first layer. The rotational speed of the grinding wheel for grinding the second layer, i.e., a second rotational speed, is lower than the rotational speed of the grinding wheel for grinding the first layer, i.e., a first rotational speed. The second layer can thus be ground effectively, as it is not necessary to use a grinding wheel with a high grinding capability or to lower a rate at which the workpiece is ground. Consequently, it is possible to maintain productivity for device chips manufactured by dividing the workpiece, and also prevent the footprint of the grinding apparatus from increasing.

Claims (46)

1 . A method of grinding a workpiece to a predetermined finishing thickness, the workpiece having a first layer including a first material and a second layer including a second material that is harder to grind than the first material and stacked on the first layer, the method comprising:

a first grinding step of grinding the first layer of the workpiece held on a chuck table with a plurality of grindstones included in a first grinding wheel and arranged in an annular array while the grinding wheel is being rotated at a first rotational speed; and

a second grinding step of grinding the second layer of the workpiece held on the chuck table with the same plurality of grindstones used during the first grinding step while the first grinding wheel is being rotated at a second rotational speed that is lower than the first rotational speed,

wherein the first grinding step is carried out after the second grinding step has been carried out, and further wherein the second grinding step is performed until the second layer has been completely removed.

2 . The method of grinding a workpiece according to claim 1 , further comprising:

between the first grinding step and the second grinding step, a spacing step of spacing the plurality of grindstones and the workpiece from each other.

3 . The method of grinding a workpiece according to claim 1 , wherein:

the first material is silicon,

the second material is silicon oxide.

4 . The method of grinding a workpiece according to claim 3 , wherein the second grinding step comes to an end upon elapse of a predetermined time after the second layer starts to be ground while the grinding wheel and the chuck table are moved relatively to each other at a predetermined speed to bring the grinding wheel and the chuck table closer to each other.

5 . The method of grinding a workpiece according to claim 3 , wherein the second grinding step comes to an end when a thickness of the workpiece that is being measured reaches a predetermined thickness.

6 . The method of grinding a workpiece according to claim 2 , wherein:

the first material is silicon,

the second material is silicon oxide.

7 . The method of grinding a workpiece according to claim 6 , wherein the second grinding step comes to an end upon elapse of a predetermined time after the second layer starts to be ground while the first grinding wheel and the chuck table are moved relatively to each other at a predetermined speed to bring the first grinding wheel and the chuck table closer to each other.

8 . The method of grinding a workpiece according to claim 6 , wherein the second grinding step comes to an end when a thickness of the workpiece that is being measured reaches a predetermined thickness.

9 . The method of grinding a workpiece according to claim 1 further comprising:

a third grinding step of grinding the first layer of the workpiece held on the chuck table with a plurality of grindstones included in a second grinding wheel different from the first grinding wheel.

10 . The method of grinding a workpiece according to claim 9 , wherein the third grinding step is carried out after the first grinding step.

11 . The method of grinding a workpiece according to claim 1 , wherein:

the first rotational speed is between 1500 rpm and 6000 rpm; and

the second rotational speed is between 700 rpm and 1500 rpm.

12 . The method of grinding a workpiece according to claim 1 , wherein the chuck table is rotated at a table rotating speed of between 100 rpm and 300 rpm during both the first and second grinding steps.

13 . The method of grinding a workpiece according to claim 11 , wherein the chuck table is rotated at a table rotating speed of between 100 rpm and 300 rpm during both the first and second grinding steps.

14 . The method of grinding a workpiece according to claim 3 , wherein:

the first rotational speed is between 1500 rpm and 6000 rpm; and

the second rotational speed is between 700 rpm and 1500 rpm.

15 . The method of grinding a workpiece according to claim 6 , wherein:

the first rotational speed is between 1500 rpm and 6000 rpm; and

the second rotational speed is between 700 rpm and 1500 rpm.

16 . The method of grinding a workpiece according to claim 1 , wherein, during both the first grinding step and the second grinding step, the grinding wheel is moved towards the chuck table at the same predetermined speed.

17 . The method of grinding a workpiece according to claim 1 , wherein, during both the first grinding step and the second grinding step, the chuck table is rotated at the same predetermined speed.

18 . The method of grinding a workpiece according to claim 1 , wherein, during both the first grinding step and the second grinding step:

the grinding wheel is moved towards the chuck table at the same predetermined speed; and

the chuck table is rotated at the same predetermined rotational speed.

19 . A method of grinding a workpiece to a predetermined finishing thickness, the workpiece having a first layer including a first material and a second layer including a second material that is harder to grind than the first material and stacked on the first layer, the method comprising:

a first grinding step of grinding the first layer of the workpiece held on a chuck table with a plurality of grindstones included in a first grinding wheel and arranged in an annular array while the grinding wheel is being rotated at a first rotational speed; and

a second grinding step of grinding the second layer of the workpiece held on the chuck table with the same plurality of grindstones used during the first grinding step while the first grinding wheel is being rotated at a second rotational speed that is lower than the first rotational speed,

wherein the first grinding step is carried out after the second grinding step has been carried out, and further wherein the second grinding step is performed until the second layer has been completely removed,

wherein the first material is silicon and the second material is silicon oxide, and

wherein, during both the first grinding step and the second grinding step:

the grinding wheel is moved towards the chuck table at the same predetermined speed; and

the chuck table is rotated at the same predetermined rotational speed.

20 . The method of grinding a workpiece according to claim 19 , wherein:

the first rotational speed is between 1500 rpm and 6000 rpm; and

the second rotational speed is between 700 rpm and 1500 rpm.