Module and method of making same

• US 20020072163A1
• Filed: 08/23/2001
• Published: 06/13/2002
• Est. Priority Date: 08/24/2000
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Nguyen, Clark T.-C, Wong, Ark-Chew
• Granted Patent: US 6,569,754 B2
• Time in Patent Office: Days
• US Class Current: 438/200
• CPC Class Codes: B81B 2203/0361 Tips, pillars
• CPC Class Codes: B81B 7/007 Interconnections between the MEMS and external electrical signals
• CPC Class Codes: B81C 1/00253 Processes for integrating an electronic processing unit with a micromechanical structure not provided for in B81C1/0023 - B81C1/00246
• CPC Class Codes: B81C 2203/019 characterised by the material or arrangement of seals between parts
• CPC Class Codes: B81C 2203/035 Soldering
• CPC Class Codes: B81C 2203/038 Bonding techniques not provided for in B81C2203/031 - B81C2203/037
• CPC Class Codes: B81C 2203/051 Active alignment, e.g. using internal or external actuators, magnets, sensors, marks or marks detectors
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 24/81 using a bump connector
• CPC Class Codes: H01L 25/0657 Stacked arrangements of devices
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01024 Chromium [Cr]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01049 Indium [In]
• CPC Class Codes: H01L 2924/01057 Lanthanum [La]
• CPC Class Codes: H01L 2924/01059 Praseodymium [Pr]
• CPC Class Codes: H01L 2924/01072 Hafnium [Hf]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/10329 : Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/3011 : Impedance

Abstract

A module bonded together at a microplatform and an improved method for making the module are provided. The method includes providing a micromechanical device including a first substrate, the microplatform, a first plurality of bonding sites on the microplatform, a micromechanical structure fabricated and supported on the microplatform and a support structure to suspend the microplatform above the first substrate. The method further includes providing a transistor circuit wafer including a second plurality of bonding sites thereon and integrated BiCMOS transistor circuits. The first and second plurality of bonding sites are aligned and compression bonded so that the microplatform is both electrically and mechanically coupled to the second substrate to form the module. The platform carrier wafer can be torn off, leaving bonded platforms behind on the substrate wafer. This allows small form factor merging of the two different technologies.

Claims

1. A method for making a module, the method comprising:

a) providing a device including a first substrate, a microplatform, at least one bonding site on the microplatform, a structure fabricated and supported on the microplatform and a support structure to suspend the microplatform above the first substrate;

b) providing a second substrate including at least one circuit bonding site thereon and a circuit;

c) aligning the at least one microplatform bonding site with the at least one circuit bonding site; and

d) bonding the at least one microplatform bonding site to the at least one circuit bonding site so that the microplatform is bonded to the second substrate at the at least one bond.

2. The method as claimed in claim 1 wherein the structure is a micromechanical structure and the circuit is an electronic circuit.

3. The method as claimed in claim 2 wherein the device has a plurality of microplatform bonding sites and the second substrate has a plurality of circuit bonding sites so that the microplatform is bonded to the second substrate at bonds and wherein the micromechanical structure is electrically coupled to the electronic circuit by at least one of the bonds.

4. The method as claimed in claim 1 further comprising forcing the first and second substrates apart to break the support structure and separate the first substrate from the second substrate.

5. The method as claimed in claim 4 wherein the device includes a plurality of microplatforms and wherein steps c) and d) are repeated with the second substrate or at least one other substrate.

6. The method as claimed in claim 3 further comprising forming bond pads and solder bumps on the second substrate wherein the bond pads serve as the circuit bonding sites.

7. The method as claimed in claim 3 wherein one of the microplatform bonding sites completely encases the structure so as to allow hermetic or vacuum encapsulation of the structure within.

8. The method as claimed in claim 2 wherein the micromechanical structure includes at least one micromechanical resonator.

9. The method as claimed in claim 8 wherein the micromechanical structure is a micromechanical filter.

10. The method as claimed in claim 1 wherein the microplatform is defined by a layer of a wafer.

11. The method as claimed in claim 10 wherein the microplatform is defined by a silicon device layer of an SOI wafer.

12. The method as claimed in claim 1 wherein the support structure includes a plurality of tethers for suspending the microplatform above the first substrate.

13. The method as claimed in claim 1 wherein the second substrate is a wafer.

14. The method as claimed in claim 13 wherein the at least one electronic circuit is a transistor circuit.

15. The method as claimed in claim 3 wherein the step of bonding includes the step of compression bonding and wherein the bonds are compression bonds.

16. The method as claimed in claim 3 further comprising selectively heating the bonds in a vacuum to vacuum encapsulate the micromechanical structure.

17. The method as claimed in claim 16 wherein the step of selectively heating includes the step of illuminating material comprising the bonds.

19. The module as claimed in claim 18 wherein the structure is a micromechanical structure and the circuit is an electronic circuit.

20. The module as claimed in claim 19 wherein the device has a plurality of microplatform bonding sites and the second substrate has a plurality of circuit bonding sites so that the microplatform is bonded to the second substrate at bonds.

21. The module as claimed in claim 20 wherein the micromechanical structure is electrically coupled to the electronic circuit by at least one of the bonds.

22. The module as claimed in claim 20 further comprising bond pads and solder bumps formed on the second substrate wherein the bond pads serve as the circuit bonding sites.

23. The module as claimed in claim 20 wherein one of the microplatform bonding sites completely encases the structure allowing hermetic or vacuum encapsulation of the structure within.

24. The module as claimed in claim 19 wherein the micromechanical structure includes at least one micromechanical resonator.

25. The module as claimed in claim 24 wherein the micromechanical structure is a micromechanical filter.

26. The module as claimed in claim 24 wherein the micromechanical structure is a mixer-filter.

27. The module as claimed in claim 18 wherein the microplatform is defined by a layer of a wafer.

28. The module as claimed in claim 27 wherein the microplatform is defined by a silicon device layer of a n SOI wafer.

29. The module as claimed in claim 18 wherein the second substrate is a wafer.

30. The module as claimed in claim 29 wherein the at least one electronic circuit is a transistor circuit.

31. The module as claimed in claim 19 wherein the micromechanical structure is vacuum-encapsulated within a cavity defined by the microplatform, the second substrate and an encompassing bonding site.

32. The module as claimed in claim 31 further comprising sealing material disposed completely around the bonding site to seal the bonding site.

18. A module comprising:

a device including a microplatform, at least one microplatform bonding site on the microplatform, and a structure fabricated and supported on the microplatform; and

a second substrate including at least one bonding site thereon and a circuit, wherein the microplatform is coupled to the second substrate at the respective microplatform and circuit bonding sites such that the microplatform is in opposed and spaced relation to the second substrate.