CMOS-MEMS integrated device including multiple cavities at different controlled pressures and methods of manufacture

• US 9,738,512 B2
• Filed: 01/22/2015
• Issued: 08/22/2017
• Est. Priority Date: 06/27/2012
• Status: Active Grant

• Current Assignee: Invensense Incorporated (TDK Corporation)
• Original Assignee: Invensense Incorporated (TDK Corporation)
• Inventors: Lee, Daesung, Shin, Jongwoo, Shin, Jong Il, Smeys, Peter, Lim, Martin
• Primary Examiner(s): Vu, David
• Assistant Examiner(s): INOUSSA, MOULOUCOULAY
• Application Number:
  US14/603,185
• Publication Number:
  US 20150129991A1
• Time in Patent Office: 943 Days
• Field of Search: 257415, 257414, 257416, 257417, 257E23193, 257723, 257E2318, 257E21501, 438 48- 52, 438455-459, 438476
• CPC Class Codes: B81B 2201/0228 Inertial sensors
• CPC Class Codes: B81B 2207/017 Smart-MEMS not provided for in B81B2207/012 - B81B2207/015
• CPC Class Codes: B81B 7/0038 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: B81B 7/0041 maintaining a controlled atmosphere with techniques not provided for in B81B7/0038
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: B81C 1/0023 Packaging together an electronic processing unit die and a micromechanical structure die MEMS packages B81B7/0032; MEMS packaging processes B81C1/00261
• CPC Class Codes: B81C 1/00285 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• 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 2203/0785 Transfer and j oin technology, i.e. forming the electronic processing unit and the micromechanical structure on separate substrates and joining the substrates

Abstract

An integrated MEMS device comprises two substrates where the first and second substrates are coupled together and have two enclosures there between. One of the first and second substrates includes an outgassing source layer and an outgassing barrier layer to adjust pressure within the two enclosures. The method includes depositing and patterning an outgassing source layer and a first outgassing barrier layer on the substrate, resulting in two cross-sections. In one of the two cross-sections a top surface of the outgassing source layer is not covered by the outgassing barrier layer and in the other of the two cross-sections the outgassing source layer is encapsulated in the outgassing barrier layer. The method also includes depositing conformally a second outgassing barrier layer and etching the second outgassing barrier layer such that a spacer of the second outgassing barrier layer is left on sidewalls of the outgassing source layer.

Claims

1. A method of preparing a first substrate comprising the steps:

depositing in a fixed location, a temperature-activated outgassing source layer comprising a non-gettering out-gassing substance on the first substrate, and resulting in two cross-sections, wherein in one of the two cross-sections a top surface of the temperature-activated outgassing source layer is exposed creating an exposed outgassing source layer and in the other of the two cross-sections there is no exposed outgassing source layer, and wherein the non-gettering out-gassing substance is configured to desorb one or more gases as a result of raising its temperature.

2. The method of claim 1, wherein the depositing comprises patterning the exposed outgassing source layer on the first substrate.

3. The method of claim 1, further comprising:

bonding a second substrate to the first substrate to create bonded substrates having a first sealed enclosure and a second sealed enclosure, wherein the first sealed enclosure includes the exposed outgassing source layer, and wherein the second sealed enclosure does not include the exposed outgassing source layer.

4. The method of claim 3, wherein the bonding includes raising the temperature of the first substrate and the second substrate to raise the temperature of the non-gettering out-gassing substance.

5. The method claim 4, wherein the raising the temperature includes raising the temperature of the exposed outgassing source layer to facilitate releasing the one or more gases in one of the first and second sealed enclosures.

6. The method claim 5, further comprising:

annealing the bonded substrates to further desorb the one or more gases from the non-gettering out-gassing substance thereby increasing pressure in the one of the first and second sealed enclosures.

7. The method claim 6, wherein the bonding includes forming an eutectic bond.

8. The method claim 6, wherein the increasing pressure in the one of the first and second sealed enclosures includes increasing pressure in the first sealed enclosure with the exposed outgassing source layer greater than that of the second sealed enclosure that does not include the exposed outgassing source layer.