Apparatus and method for chamfering wafer

• US 6,267,648 B1
• Filed: 05/14/1999
• Issued: 07/31/2001
• Est. Priority Date: 05/18/1998
• Status: Expired due to Fees

• Current Assignee: Tokyo Seimitsu Company Limited
• Original Assignee: Tokyo Seimitsu Company Limited
• Inventors: Ikeda, Kazumi, Katayama, Ichiro, Iwaki, Masatami
• Primary Examiner(s): Eley, Timothy V.
• Assistant Examiner(s): BERRY JR, WILLIE WENDELL
• Application Number:
  US09/311,567
• Time in Patent Office: 809 Days
• Field of Search: 451/41, 451/43, 451/44
• US Class Current: 451/44
• CPC Class Codes: B24B 51/00 Arrangements for automatic control of a series of individual steps in grinding a workpiece if applicable to other machine tools, G05B takes precedence
• CPC Class Codes: B24B 9/065 of thin, brittle parts, e.g. semiconductors, wafers
• CPC Class Codes: H01L 21/02021 Edge treatment, chamfering

Abstract

A grindstone and a wafer are rotated at high speeds in the same direction. The rotating wafer is slowly moved toward the rotating grindstone to thereby gradually chamfer the periphery of the wafer.

Claims

1. A wafer chamfering method comprising the steps of:

rotating a grindstone and a wafer at high speeds;

getting the grindstone and the wafer closer to each other including getting the grindstone and the wafer closer to each by a predetermined distance and stopping to get the grindstone and the wafer closer to each other for a predetermined period, thereby gradually chamfering a periphery of the wafer by the grindstone,

wherein the step of getting the grindstone and the wafer closer to each other is repeated.

2. The wafer chamfering method as defined in claim 1, wherein, in the rotating step, the grindstone is rotated at a circumferential speed of at least 1,000 m/min, and the wafer is rotated at a circumferential speed of at least 30 m/min.

3. The wafer chamfering method as defined in claim 1, further comprising the step of:

rotating the wafer at a low speed to finely chamfer the periphery of the wafer, after the periphery of the wafer is chamfered by a predetermined amount.

4. The wafer chamfering method as defined in claim 3, wherein, in the step of rotating the wafer at the low speed, the wafer is rotated at a circumferential speed of between 0.3 m/min and 3 m/min.

5. The wafer chamfering method as defined in claim 1, wherein at least one of a circumferential speed of the wafer and a circumferential speed of the grindstone is periodically changed within a range of a high speed.

6. The wafer chamfering method as defined in claim 1, wherein at least one of a rotating direction of the wafer and a rotating direction of the grindstone is periodically changed.

7. The wafer chamfering method as defined in claim 6, wherein the wafer and the grindstone are stopped being got closer to each other while at least one of the rotating direction of the wafer and the rotating direction of the grindstone is being changed.

8. A wafer chamfering method comprising the steps of:

arranging a grindstone and a wafer separately on two parallel straight lines with a predetermined interval;

rotating the grindstone and the wafer at high speeds;

moving at least one of the wafer and the grindstone on the straight line to bring the grindstone into contact with a periphery of the wafer including getting the grindstone and the wafer closer to each by a predetermined distance and stopping to get the grindstone and the wafer closer to each other for a predetermined period, thereby gradually chamfering the periphery of the wafer by the grindstone,

wherein the step of moving at least one of the wafer and the grindstone is repeated.

9. The wafer chamfering method as defined in claim 8, wherein the predetermined interval between the two straight lines is the sum of a radius of the grindstone and a radius of the wafer after the chamfering.

10. The wafer chamfering method as defined in claim 8, wherein, in the rotating step, the grindstone is rotated at a circumferential speed of at least 1,000 m/min, and the wafer is rotated at a circumferential speed of at least 30 m/min.

11. The wafer chamfering method as defined in claim 8, further comprising the step of:

rotating the wafer at a low speed to finely chamfer the periphery of the wafer, after the periphery of the wafer is chamfered by a predetermined amount.

12. The wafer chamfering method as defined in claim 11, wherein, in the step of rotating the wafer at the low speed, the wafer is rotated at a circumferential speed of between 0.3 m/min and 3 m/min.

13. The wafer chamfering method as defined in claim 8, wherein at least one of a circumferential speed of the wafer and a circumferential speed of the grindstone is periodically changed within a range of a high speed.

14. The wafer chamfering method as defined in claim 8, wherein at least one of a rotating direction of the wafer and a rotating direction of the grindstone is periodically changed.

15. The wafer chamfering method as defined in claim 14, wherein the wafer and the grindstone are stopped being got closer to each other while at least one of the rotating direction of the wafer and the rotating direction of the grindstone is being changed.

16. A wafer chamfering method, comprising the steps of:

roughly chamfering a periphery of a rotating wafer by a first rotating grindstone with a large diameter by getting the rotating wafer and the first rotating grindstone closer to each other; and

finely chamfering the periphery of the rotating wafer by a second rotating grindstone with a small diameter by getting the rotating wafer and the second rotating grindstone closer to each other.

17. The wafer chamfering method as defined in claim 16, wherein the first rotating grindstone has a diameter of between 100 mm and 300 mm, and the second rotating grindstone has a diameter of between 2 mm and 50 mm.

18. The wafer chamfering method as defined in claim 16, wherein the second grindstone is a resin-bond grindstone.

19. The wafer chamfering method as defined in claim 16, wherein the second grindstone has a groove of a trapezoidal section at a periphery thereof, and is inclined at a predetermined angle along a tangent line of the rotating wafer.

20. The wafer chamfering method as defined in claim 19, wherein:

the groove at the periphery of the second grindstone has first and second arc surfaces at both edges thereof, respectively; and

the finely chamfering step comprises the steps of;

bringing the peripheral surface of the rotating wafer into contact with a flat surface of the groove of the second grindstone;

moving the rotating wafer along the flat surface of the groove of the second grindstone to thereby bring a first chamfered surface of the periphery of the rotating wafer into contact with a first sloping surface of the groove of the second grindstone;

moving the rotating wafer along the first sloping surface and the first arc surface of the groove of the second grindstone to grind a first corner of the peripheral surface of the rotating wafer;

bringing the peripheral surface of the rotating wafer into contact with the flat surface of the groove of the second grindstone;

moving the wafer along the flat surface of the groove of the second grindstone to thereby bring a second chamfered surface of the periphery of the rotating wafer into contact with a second sloping surface of the groove of the second grindstone; and

moving the rotating wafer along the second sloping surface and the second arc surface of the groove of the second grindstone to grind a second comer of the peripheral surface of the rotating wafer.

21. The wafer chamfering method as defined in claim 20, wherein:

the first comer of the peripheral surface of the rotating wafer is ground at the same curvature as the first arc surface of the groove of the second grindstone; and

the second corner of the peripheral surface of the rotating wafer is ground at the same curvature as the second arc surface of the groove of the second grindstone.