CMOS-MEMS INTEGRATED DEVICE INCLUDING MULTIPLE CAVITIES AT DIFFERENT CONTROLLED PRESSURES AND METHODS OF MANUFACTURE

• US 20150129991A1
• Filed: 01/22/2015
• Published: 05/14/2015
• Est. Priority Date: 06/27/2012
• Status: Active Grant

• Current Assignee: Invensense Incorporated (TDK Corporation)
• Original Assignee: Invensense Incorporated (TDK Corporation)
• Inventors: SHIN, Jongwoo, LIM, Martin, LEE, Daesung, SHIN, Jong Il, SMEYS, Peter
• Granted Patent: US 9,738,512 B2
• Time in Patent Office: Days
• US Class Current: 257/415
• 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. An integrated MEMS device comprising:

a first substrate; and

a second substrate, wherein the first and second substrates are coupled together and have at least two enclosures there between;

wherein one of the first and second substrates include an outgassing source layer and an outgassing barrier layer to adjust pressure within the at least two enclosures.

2. The device of claim 1 wherein the enclosure pressure adjustment is provided by creating two cross-sections:

wherein 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.

3. The device of claim 1 which includes an intermediate layer between the outgassing source layer and the first outgassing barrier layer.

4. A method of preparing a substrate comprising the steps:

depositing and patterning an outgassing source layer and a first outgassing barrier layer on the substrate, resulting in two cross-sections;

wherein 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;

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.

5. The method of claim 4, wherein the outgassing source layer is deposited and patterned;

and the first outgassing barrier layer is deposited and etched using one or more masks.

6. The method of claim 4, which includes bonding a second substrate to the first substrate to provide first and second sealed enclosures, wherein the first sealed enclosure includes one of the two cross-sections and the second sealed enclosure includes the other of the two cross-sections.

7. The method of claim 6, wherein at least one of the first and second substrate includes an integrated circuit.

8. The method of claim 6, which includes raising the temperature of the first substrate and the second substrate during the bonding step.

9. The method claim 8, wherein the outgassing source layer releases gas in one of the first and second sealed enclosures during the bonding step.

10. The method claim 9, further comprising annealing the bonded substrates to increase pressure in one of the first and second sealed enclosures.

11. The method claim 10, wherein the bonding is achieved by an eutectic bond.

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

depositing an outgassing source layer on the first substrate, resulting in two cross-sections;

wherein in one of the two cross-sections a top surface of the outgassing source layer and in the other of the two cross-sections there is no outgassing source layer.

13. The method of claim 12, wherein the depositing step comprises patterning the outgassing source layer on the first substrate.

14. The method of claim 12, which includes bonding a second substrate to the first substrate to provide first and second sealed enclosures, wherein the first sealed enclosure includes the outgassing source layer and the second sealed enclosure which does not include the outgassing source layer.

15. The method of claim 14, which includes raising the temperature of the first substrate and the second substrate during the bonding step.

16. The method claim 15, wherein the outgassing source layer releases gas in one of the first and second sealed enclosures during the bonding step.

17. The method claim 16, further comprising annealing the bonded substrates to increase pressure in one of the first and second sealed enclosures.

18. The method claim 17, wherein the bonding is achieved by an eutectic bond.