Use of a saw frame with tape as a substrate carrier for wafer level backend processing

• US 5,389,182 A
• Filed: 08/02/1993
• Issued: 02/14/1995
• Est. Priority Date: 08/02/1993
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Mignardi, Michael A.
• Primary Examiner(s): Simmons, David A.
• Assistant Examiner(s): Osele, Mark A.
• Application Number:
  US08/101,122
• Time in Patent Office: 561 Days
• Field of Search: 156/344, 156/584, 437/226, 29/412, 29/413, 29/415, 29/426.1, 29/426.5, 29/426.6
• US Class Current: 156/701
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81C 1/00896 Temporary protection during separation into individual elements
• CPC Class Codes: B81C 99/004 during manufacturing
• CPC Class Codes: G01P 2015/0831 the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration
• CPC Class Codes: Y10S 156/93 Semiconductive product delaminating, e.g. delaminating emiconductive wafer from underlayer
• CPC Class Codes: Y10T 156/11 Methods of delaminating, per se; i.e. , separating at bonding face
• CPC Class Codes: Y10T 156/19 Delaminating means
• CPC Class Codes: Y10T 29/49789 Obtaining plural product pieces from unitary workpiece
• CPC Class Codes: Y10T 29/49794 Dividing on common outline

Abstract

A method for processing a wafer containing microelectronic mechanical devices that allows all fabrication and test steps to be performed in wafer form instead of device form. The water 20 is mounted in a saw frame 24 on dicing tape 22 and the individual devices 27 separated, typically by sawing, prior to completing device fabrication. The devices are left on the dicing tape during the remaining fabrication steps. Some fabrication steps may require covering the adhesive of the dicing tape with a protective cover 44. After all fabrication steps including the application of a protective overcoat and functional testing are completed, the devices are removed from the dicing tape and packaged.

Claims

1. A method of fabricating a microelectronic device comprising the steps of:

providing a piece of dicing tape having an adhesive side;

mounting a wafer on the adhesive side of said dicing tape, said wafer containing partially fabricated devices;

subdividing said wafer to separate said partially fabricated devices, said separated devices remaining mounted to said dicing tape;

placing a protective cover over exposed portions of the adhesive side of said dicing tape;

continuing the fabrication of said separated devices while the protective cover remains over the exposed portions of the adhesive side of said dicing tape; and

removing said devices from said dicing tape.

2. The method of claim 1 wherein said protective cover is selected from the group consisting of ceramic, metal, quartz and dicing tape.

3. The method of claim 1 and further comprising applying a temporary protective coating to said devices prior to said subdividing step.

4. The method of claim 3 further comprising the step of removing said temporary protective coating from said devices.

5. The method of claim 1 wherein said devices are digital micromirror devices.

6. The method of claim 1 wherein said devices are accelerometers.

7. The method of claim 1 wherein said continuing fabrication step includes plasma etching said devices.

8. The method of claim 1 wherein said continuing fabrication step comprises passivating said devices.

9. The method of claim 1 wherein said continuing fabrication step comprises testing said devices.

10. A method of fabricating a digital micromirror device comprising the steps of:

providing a piece of dicing tape having an adhesive side;

mounting a wafer on the adhesive side of said dicing tape, said wafer containing partially fabricated digital micromirror devices;

subdividing said wafer to separate said partially fabricated digital micromirror devices, said separated digital micromirror devices remaining mounted to said dicing tape;

placing a protective cover, selected from the group consisting of ceramic, metal, quartz and dicing tape, over exposed portions of the adhesive side of said dicing tape;

continuing the fabrication of said separated digital micromirror devices while the protective cover remains over the exposed portions of the adhesive side of said dicing tape; and

removing said digital micromirror devices from said dicing tape.

11. The method of claim 10 wherein said continuing fabrication step includes plasma etching said digital micromirror devices.

12. The method of claim 10 wherein said continuing fabrication step comprises passivating said digital micromirror devices.

13. The method of claim 10 wherein said continuing fabrication step comprises testing said digital micromirror devices.

14. The method of claim 10 and further comprising applying a temporary protective coating to said digital micromirror devices prior to said subdividing step.

15. The method of claim 14 further comprising the step of removing said temporary protective coating from said digital micromirror devices.

16. A method of fabricating an accelerometer comprising the steps of:

providing a piece of dicing tape having an adhesive side;

mounting a wafer on the adhesive side of said dicing tape, said wafer containing partially fabricated accelerometers;

subdividing said wafer to separate said partially fabricated accelerometers, said separated accelerometers remaining mounted to said dicing tape;

placing a protective cover, selected from the group consisting of ceramic, metal, quartz and dicing tape, over exposed portions of the adhesive side of said dicing tape;

continuing the fabrication of said separated accelerometers while the protective cover remains over the exposed portions of the adhesive side of said dicing tape; and

removing said accelerometers from said dicing tape.

17. The method of claim 16 wherein said continuing fabrication step includes plasma etching said accelerometers.

18. The method of claim 16 wherein said continuing fabrication step comprises passivating said accelerometers.

19. The method of claim 16 wherein said continuing fabrication step comprises testing said accelerometers.