Method for protecting encapsulated sensor structures using stack packaging

• US 20040197953A1
• Filed: 03/31/2003
• Published: 10/07/2004
• Est. Priority Date: 03/31/2003
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Funk, Karsten
• Granted Patent: US 7,335,971 B2
• Time in Patent Office: Days
• US Class Current: 438/108
• CPC Class Codes: B81B 2207/095 through the lid
• CPC Class Codes: B81C 1/00333 Aspects relating to packaging of MEMS devices, not covered by groups B81C1/00269 - B81C1/00325
• CPC Class Codes: B81C 2203/0136 Growing or depositing of a covering layer
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: H01L 2224/05554 being square
• CPC Class Codes: H01L 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation

Abstract

A method of protecting a micro-mechanical sensor structure embedded in a micro-mechanical sensor chip, in which the micro-mechanical sensor structure is fabricated with a protective membrane, the micro-mechanical sensor chip is arranged so that a surface of the protective membrane faces toward a second chip, and the micro-mechanical sensor chip is secured to the second chip.

Claims

1. A method of protecting a micro-mechanical sensor structure embedded in a micro-mechanical sensor chip, comprising:

fabricating the micro-mechanical sensor structure with a protective membrane;

arranging the micro-mechanical sensor chip so that a surface of the protective membrane faces toward a second chip; and

securing the micro-mechanical sensor chip to the second chip.

2. The method of claim 1, further comprising:

configuring the protective membrane at a reduced thickness.

3. The method of claim 1, wherein the protective membrane is configured using a chemical and mechanical planarization process.

4. The method of claim 1, wherein a thickness of the protective membrane is less than 10 microns.

5. The method of claim 1, further comprising:

configuring a sealing bond ring to surround the micro-mechanical sensor structure.

6. The method of claim 1, wherein the protective membrane includes an opening.

7. The method of claim 1, wherein the protective membrane is configured to be at least partially absent.

8. The method of claim 1, further comprising:

applying a bond between the micro-mechanical sensor chip and the second chip to secure the micro-mechanical sensor chip to the second chip.

9. The method of claim 1, further comprising:

arranging the micro-mechanical sensor chip and the second chip on a package frame to support the micro-mechanical sensor chip and the second chip in a single package; and

applying a plastic mold to seal the micro-mechanical sensor chip and the second chip in the single package.

10. The method of claim 1, further comprising:

arranging at least one additional micro-mechanical sensor chip at least one of on, underneath, and between the micro-mechanical sensor chip and the second chip to provide a multi-sensor device.

11. The method of claim 10, wherein the multi-sensor device includes at least one of an accelerometer, a gyroscope, a temperature sensor, and a pressure sensor.

12. The method of claim 10, wherein the multi-sensor device includes at least one of a multi-dimensional accelerometer and a multi-dimensional gyroscope.

13. The method of claim 1, wherein the embedded micro-mechanical sensor structure is sensitive to one of a pressure, an acceleration, a rotation, and a temperature.

14. The method of claim 1, wherein the second chip is at least one of an electronic integrated circuit chip and an actuator chip.

15. The method of claim 1, further comprising:

applying a bond between the micro-mechanical sensor chip and the second chip to secure the micro-mechanical sensor chip to the second chip;

arranging the micro-mechanical sensor chip and the second chip on a package frame to support the micro-mechanical sensor chip and the second chip in a single package; and

applying a plastic mold to seal the micro-mechanical sensor chip and the second chip in the single package.

16. The method of claim 15, wherein the protective membrane is configured using a chemical and mechanical planarization process.

17. The method of claim 15, wherein a thickness of the protective membrane is less than 10 microns

18. The method of claim 1, further comprising:

configuring a sealing bond ring to surround the micro-mechanical sensor structure;

arranging the micro-mechanical sensor chip and the second chip on a package frame to support the micro-mechanical sensor chip and the second chip in a single package; and

applying a plastic mold to seal the micro-mechanical sensor chip and the second chip in the single package.

19. The method of claim 18, wherein the protective membrane includes an opening.

20. The method of claim 18, wherein the protective membrane is configured to be at least partially absent.

21. A micro-mechanical sensor device, comprising:

a first chip; and

a micro-mechanical sensor chip having an embedded micro-mechanical sensor structure and a protective membrane arranged on the embedded micro-mechanical sensor structure, wherein the micro-mechanical sensor chip is arranged onto the first chip so that the protective membrane faces toward the first chip.

22. The micro-mechanical sensor device of claim 21, wherein the protective membrane is configured at a reduced thickness.

23. The micro-mechanical sensor device of claim 21, wherein a thickness of the protective membrane is less than 10 microns.

24. The micro-mechanical sensor device of claim 21, further comprising:

a bond to secure the micro-mechanical sensor chip to the first chip.

25. The micro-mechanical sensor device of claim 21, further comprising:

a sealing bond ring to surround the embedded micro-mechanical structure.

26. The micro-mechanical sensor device of claim 21, wherein the protective membrane includes an opening.

27. The micro-mechanical sensor device of claim 21, wherein the protective membrane is at least partially absent.

28. The micro-mechanical sensor device of claim 21, further comprising:

a package frame to support the first chip and the micro-mechanical sensor chip in a single package; and

a plastic mold to seal the first chip and the micro-mechanical sensor chip in the single package.

29. The micro-mechanical sensor device of claim 21, further comprising:

at least one additional micro-mechanical sensor chip arranged at least one of on, underneath, and between the micro-mechanical sensor chip and the first chip to provide a multi-sensor device.

30. The micro-mechanical sensor device of claim 29, wherein the multi-sensor device includes at least one of an accelerometer, a gyroscope, a temperature sensor, and a pressure sensor.

31. The micro-mechanical sensor device of claim 29, wherein the multi-sensor device includes at least one of a multi-dimensional accelerometer and a multi-dimensional gyroscope.

32. The micro-mechanical sensor device of claim 21, wherein the embedded micro-mechanical sensor structure is sensitive to one of a pressure, acceleration, a rotation, and a temperature.

33. The micro-mechanical sensor device of claim 21, wherein the first chip is at least one of an electronic integrated circuit chip and an actuator chip.

34. The micro-mechanical sensor device of claim 21, further comprising:

an RF chip arranged on the micro-mechanical sensor chip for wireless communication.

35. The micro-mechanical sensor device of claim 34, further comprising:

a substrate, wherein a difference in dielectric coefficient for the RF chip as an upper chip and an additional space between the upper RF chip and the substrate provided by the use of the micro-mechanical sensor chip as an intermediate chip provides an improved RF performance.

36. The micro-mechanical sensor device of claim 21, further comprising:

a bond to secure the micro-mechanical sensor chip to the first chip;

a package frame to support the first chip and the micro-mechanical sensor chip in a single package; and

a plastic mold to seal the first chip and the micro-mechanical sensor chip in the single package;

wherein the protective membrane is configured at a reduced thickness.

37. The micro-mechanical sensor device of claim 36, wherein a thickness of the protective membrane is less than 10 microns.

38. The micro-mechanical sensor device of claim 21, further comprising:

a sealing bond ring to surround the embedded micro-mechanical structure;

a package frame to support the first chip and the micro-mechanical sensor chip in a single package; and

a plastic mold to seal the first chip and the micro-mechanical sensor chip in the single package;

wherein the protective membrane is at least partially absent.

39. A method of protecting a micro-mechanical sensor structure embedded in a micro-mechanical sensor chip, comprising:

fabricating the micro-mechanical sensor structure with a sealing bond to surround the micro-mechanical sensor structure;

arranging the micro-mechanical sensor chip so that a surface of the protective membrane faces toward a second chip; and

securing the micro-mechanical sensor chip to the second chip.