Wafer cutting using laser marking

• US 20040161877A1
• Filed: 02/12/2004
• Published: 08/19/2004
• Est. Priority Date: 06/05/2002
• Status: Active Grant

• Current Assignee: Lamberto V. Nepomuceno, Reginald T. Taar, Reynaldo S. Atienza Jr
• Original Assignee: Lamberto V. Nepomuceno, Reginald T. Taar, Reynaldo S. Atienza Jr
• Inventors: Atienza, Reynaldo S. Jr., Taar, Reginald T., Nepomuceno, Lamberto V.
• Granted Patent: US 6,911,377 B2
• Time in Patent Office: Days
• US Class Current: 438/110
• CPC Class Codes: B23K 26/08 Devices involving relative movement between laser beam and workpiece
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: H01L 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304

Abstract

An embodiment of the present invention includes a chuck, an imaging sensor, and a laser. The chuck holds a wafer having a front side attached to a tape. The imaging sensor obtains a scribe pattern on the front side through the tape. The laser is mounted above the chuck to mark an alignment pattern on a back side of the wafer based on the scribe pattern.

Claims

1. A method comprising:

placing a wafer on a chuck, the wafer having a front side attached to a tape;

obtaining a scribe pattern on the front side through the tape by an imaging sensor; and

marking an alignment pattern on a back side of the wafer using a laser based on the scribe pattern, the laser being mounted above the chuck.

2. The method of claim 1 wherein placing the wafer comprises:

placing the wafer front side up on the chuck.

3. The method of claim 2 wherein obtaining the scribe pattern comprises:

obtaining the scribe pattern on the front side by the imaging sensor mounted above the wafer.

4. The method of claim 3 further comprising:

flipping the wafer to turn the back side up.

5. The method of claim 1 wherein placing the wafer comprises:

placing the wafer back side up on the chuck.

6. The method of claim 5 wherein obtaining the scribe pattern comprises:

obtaining the scribe pattern on the front side by the imaging sensor mounted underneath the wafer.

7. The method of claim 1 wherein marking the alignment pattern comprises:

receiving the scribe pattern from the imaging sensor; and

emitting a laser beam from the laser to etch the alignment pattern on the back side, the alignment pattern being directly opposite to the scribe pattern.

8. The method of claim 1 further comprising:

recognizing the alignment pattern on the back side of the wafer.

9. The method of claim 8 further comprising:

cutting the back side of the wafer based on the alignment pattern.

10. The method of claim 1 further comprising:

recognizing the scribe pattern; and

saving the scribe pattern in a memory.

11. A method comprising:

controlling an imaging sensor to obtain a scribe pattern on a front side of a wafer placed on a chuck, the front side being attached a tape;

recognizing the scribe pattern; and

controlling a laser to mark an alignment pattern on a back side of the wafer based on the scribe pattern, the laser being mounted above the chuck.

12. The method of claim 11 wherein controlling the imaging sensor comprises:

controlling the imaging sensor mounted above the wafer.

13. The method of claim 11 wherein controlling the imaging sensor comprises:

controlling the imaging sensor mounted underneath the wafer.

14. The method of claim 11 wherein controlling the laser comprises:

emitting a laser beam from the laser to etch the alignment pattern on the back side, the alignment pattern being directly opposite to the scribe pattern.

15. The method of claim 11 further comprising:

activating a flipping mechanism to turn the back side of the wafer up.

16. The method of claim 11 further comprising:

saving the scribe pattern in a memory.

17. The method of claim 11 further comprising:

recognizing the alignment pattern on the back side of the wafer.

18. The method of claim 17 further comprising:

controlling a cutter to cut the back side of the wafer based on the alignment pattern.

19. An article of manufacture comprising:

a machine-accessible medium including data that, when accessed by a machine, causes the machine to;

control an imaging sensor to obtain a scribe pattern on a front side of a wafer placed on a chuck, the front side being attached a tape;

recognize the scribe pattern; and

control a laser to mark an alignment pattern on a back side of the wafer based on the scribe pattern, the laser being mounted above the chuck.

20. The article of manufacture of claim 19 wherein the data causing the machine to control the imaging sensor comprises data that, when accessed by the machine, causes the machine to:

control the imaging sensor mounted above the wafer.

21. The article of manufacture of claim 19 wherein the data causing the machine to control the imaging sensor comprises data that, when accessed by the machine, causes the machine to:

control the imaging sensor mounted underneath the wafer.

22. The article of manufacture of claim 19 wherein the data causing the machine to control the laser comprises data that, when accessed by the machine, causes the machine to:

emit a laser beam from the laser to etch the alignment pattern on the back side, the alignment pattern being directly opposite to the scribe pattern.

23. The article of manufacture of claim 19 wherein the data further comprises data that, when accessed by the machine, causes the machine to:

activate a flipping mechanism to turn the back side of the wafer up.

24. The article of manufacture of claim 19 wherein the data further comprises data that, when accessed by the machine, causes the machine to:

save the scribe pattern in a memory.

25. The article of manufacture of claim 19 wherein the data further comprises data that, when accessed by the machine, causes the machine to:

recognize the alignment pattern on the back side of the wafer.

26. The article of manufacture of claim 25 wherein the data further comprises data that, when accessed by the machine, causes the machine to:

control a cutting mechanism to cut the back side of the wafer based on the alignment pattern.

29. The system of claim 26 wherein the imaging sensor is mounted above the wafer.

31. The system of claim 25 wherein the chuck holds the wafer back side up.

32. The system of claim 29 wherein the imaging sensor is mounted underneath the wafer.

33. The system of claim 25 wherein the laser emits a laser beam from the laser to etch the alignment pattern on the back side, the alignment pattern being directly opposite to the scribe pattern.

34. The system of claim 25 further comprising:

a processing unit to recognize the alignment pattern on the back side of the wafer.

35. The system of claim 32 further comprising:

a cutter to cut the back side of the wafer based on the alignment pattern.

36. The system of claim 32 wherein the processing unit recognizes the scribe pattern and saves the scribe pattern in a memory.

27. A system comprising:

a chuck to hold a wafer, the wafer having a front side attached to a tape;

an imaging sensor to obtain a scribe pattern on the front side through the tape; and

a laser mounted above the chuck to mark an alignment pattern on a back side of the wafer based on the scribe pattern.

28. The system of claim 27 wherein the chuck holds the wafer front side up.

30. The system of claim 27 further comprising:

a flipping mechanism to turn up the back side of the wafer.