Method and device for protecting micro electromechanical system structures during dicing of a wafer

• US 6,555,417 B2
• Filed: 12/05/2001
• Issued: 04/29/2003
• Est. Priority Date: 12/05/2000
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Harney, Kieran P., Spooner, Timothy R.
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Nhu, David
• Application Number:
  US10/007,579
• Publication Number:
  US 20020076873A1
• Time in Patent Office: 510 Days
• Field of Search: 438/48, 438/51, 438/55, 438/64, 438/68, 438/113, 438/114, 438/106, 438/128, 438/183, 438/460
• US Class Current: 438/113
• CPC Class Codes: B81C 1/00888 Multistep processes involving only mechanical separation, e.g. grooving followed by cleaving
• CPC Class Codes: B81C 1/00896 Temporary protection during separation into individual elements
• CPC Class Codes: H01L 21/6836 Wafer tapes, e.g. grinding or dicing support tapes adhesive tapes in general C09J7/20
• CPC Class Codes: H01L 2221/68327 used during dicing or grinding

Abstract

A wafer cap protects micro electromechanical system (“MEMS”) structures during a dicing of a MEMS wafer to produce individual MEMS dies. A MEMS wafer is prepared having a plurality of MEMS structure sites thereon. Upon the MEMS wafer, the wafer cap is mounted to produce a laminated MEMS wafer. The wafer cap is recessed in areas corresponding to locations of the MEMS structure sites on the MEMS wafer. The capped MEMS wafer can be diced into a plurality of MEMS dies without causing damage to or contaminating the MEMS die.

Claims

1. A method for protecting a MEMS structure during a dicing of a MEMS wafer to produce individual MEMS dies, comprising the steps of:

(a) preparing a MEMS wafer having a plurality of MEMS structure sites thereon;

(b) mounting, upon the MEMS wafer, punched tape, the punched tape having holes in areas corresponding to locations of the MEMS structure sites on the MEMS wafer;

(c) mounting, upon the punched tape, a cover tape to produce a laminated MEMS wafer, the cover tape being without openings; and

(d) dicing the laminated MEMS wafer into a plurality of MEMS dies.

2. The method as claimed in claim 1, wherein the laminated MEMS wafer is diced using a saw.

3. The method as claimed in claim 1, wherein the laminated MEMS wafer is diced using a laser.

4. The method as claimed in claim 1, wherein the laminated MEMS wafer is diced using scribing and breaking.

5. The method as claimed in claim 1, wherein the cover tape includes an adhesive medium.

6. The method as claimed in claim 5, wherein the adhesive medium is an ultraviolet light releasable medium.

7. The method as claimed in claim 5, wherein the adhesive medium is a heat releasable medium.

8. The method as claimed in claim 5, wherein the adhesive medium is a combination of an ultraviolet light and heat releasable medium.

9. The method as claimed in claim 5, wherein the adhesive medium comprises a thermoplastic organic material.

10. The method as claimed in claim 5, wherein the adhesive medium comprises an ultraviolet light sensitive organic material.

11. The method as claimed in claim 1, further comprising the step of:

(e) applying a contiguous tape on a backside of the MEMS wafer, the backside of the MEMS wafer being a side opposite of a side having the MEMS structure sites located thereon.

12. The method as claimed in claim 11, wherein the contiguous tape is applied to a backside of the MEMS wafer after the cover tape is mounted on the MEMS wafer.

13. The method as claimed in claim 11, wherein the contiguous tape is applied to a backside of the MEMS wafer before the cover tape is mounted on the MEMS wafer.

14. The method as claimed in claim 1, wherein the laminated MEMS wafer is diced with a wafer saw with a cover tape side of the laminated MEMS wafer facing towards a cutting device of the wafer saw such that the wafer cap is sawn before the MEMS wafer.

15. The method as claimed in claim 1, further comprising the step of:

(e) removing individual dies from the diced laminated MEMS wafer before the wafer cap is removed from the laminated MEMS wafer.

16. The method as claimed in claim 1, further comprising the step of:

(e) mounting dies from the diced laminated MEMS wafer into a package before the wafer cap is removed from the laminated MEMS wafer.

17. The method as claimed in claim 1, further comprising the step of:

(e) mounting dies from the diced laminated MEMS wafer into a package after the wafer cap is removed from the laminated MEMS wafer.

18. The method as claimed in claim 1, wherein the cover tape comprises a static dissipative material.

19. The method as claimed in claim 1, wherein the punched tape comprises a static dissipative material.

20. The method as claimed in claim 11, wherein the contiguous tape comprises a static dissipative material.