STRUCTURES AND FORMATION METHODS OF MICRO-ELECTRO MECHANICAL SYSTEM DEVICE

• US 20150284240A1
• Filed: 05/13/2014
• Published: 10/08/2015
• Est. Priority Date: 11/19/2013
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: CHU, Chia-Hua, CHENG, Chun-Wen, TSAI, Shang-Ying, LIANG, Chin-Wei
• Granted Patent: US 9,567,206 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 1/00238 Joining a substrate with an electronic processing unit and a substrate with a micromechanical structure
• CPC Class Codes: B81C 1/00293 maintaining a controlled atmosphere with processes not provided for in B81C1/00285

Abstract

A micro-electro mechanical system (MEMS) device is provided. The MEMS device includes a cap substrate and a MEMS substrate bonded with the cap substrate. The MEMS substrate includes a first movable element and a second movable element. The MEMS device also includes a first closed chamber between the MEMS substrate and the cap substrate, and the first movable element is in the first closed chamber. The MEMS device further includes an outgassing layer in the first closed chamber. In addition, the MEMS device includes a second closed chamber between the MEMS substrate and the cap substrate, and the second movable element is in the second closed chamber.

Claims

1. A micro-electro mechanical system (MEMS) device, comprising:

a cap substrate;

a MEMS substrate bonded with the cap substrate, wherein the MEMS substrate comprises at least one first movable element and at least one second movable element;

a first closed chamber between the MEMS substrate and the cap substrate, wherein the first movable element is in the first closed chamber;

an outgassing layer in the first closed chamber; and

a second closed chamber between the MEMS substrate and the cap substrate, wherein the second movable element is in the second closed chamber.

2. The MEMS device as claimed in claim 1, wherein the outgassing layer is in direct contact with the cap substrate.

3. The MEMS device as claimed in claim 1, wherein the outgassing layer comprises a dielectric material.

4. The MEMS device as claimed in claim 3, wherein the outgassing layer comprises a silicon oxide layer capable of releasing gas.

5. The MEMS device as claimed in claim 1, wherein the cap substrate comprises a recess, and the outgassing layer is on a bottom of the recess.

6. The MEMS device as claimed in claim 1, wherein the outgassing layer is in direct contact with the MEMS substrate.

7. The MEMS device as claimed in claim 1, wherein the cap substrate comprises a complimentary metal-oxide-semiconductor (CMOS) substrate with a dielectric layer facing the first closed chamber and the second closed chamber.

8. The MEMS device as claimed in claim 7, wherein the outgassing layer comprises the dielectric layer of the CMOS substrate facing the first closed chamber.

9. The MEMS device as claimed in claim 7, further comprising a gas-blocking layer between the second closed chamber and the dielectric layer of the CMOS substrate.

10. The MEMS device as claimed in claim 1, further comprising a bonding element between the MEMS substrate and the cap substrate.

11. A micro-electro mechanical system (MEMS) device, comprising:

a cap substrate;

a MEMS substrate bonded with the cap substrate, wherein the MEMS substrate comprises at least one first movable element and at least one second movable element;

a first closed chamber between the MEMS substrate and the cap substrate, wherein the first movable element is in the first closed chamber;

a second closed chamber between the MEMS substrate and the cap substrate, wherein the second movable element is in the second closed chamber; and

an outgassing layer in the first closed chamber and on the cap substrate.

12. The MEMS device as claimed in claim 11, wherein the cap substrate comprises a complimentary metal-oxide-semiconductor (CMOS) substrate with a dielectric layer facing the first closed chamber and the second closed chamber.

13. The MEMS device as claimed in claim 12, wherein the outgassing layer comprises the dielectric layer of the CMOS substrate facing the first closed chamber.

14. The MEMS device as claimed in claim 13, further comprising a gas-blocking layer between the second closed chamber and the dielectric layer of the CMOS substrate.

15. The MEMS device as claimed in claim 11, further comprising a bonding element between the MEMS substrate and the cap substrate.

16. A method for forming a micro-electro mechanical system (MEMS) device, comprising:

forming a MEMS substrate, wherein the MEMS substrate comprises at least one first movable element and at least one second movable element;

bonding a cap substrate with the MEMS substrate to form a first closed chamber and a second closed chamber between the cap substrate and the MEMS substrate, wherein the first movable element is in the first closed chamber and the second movable element is in the second closed chamber; and

changing the pressure of the first closed chamber to be a first pressure after the first closed chamber is formed, wherein the first pressure and a second pressure of the second closed chamber are different from each other.

17. The method for forming a MEMS device as claimed in claim 16, wherein the step of changing the pressure to be the first pressure comprises:

forming an outgassing layer on the cap substrate, wherein the outgassing layer is in the first closed chamber after the first closed chamber is formed, and the outgassing layer releases gas in the first closed chamber such that the pressure is increased to be the first pressure.

18. The method for forming a MEMS device as claimed in claim 16, further comprising:

forming a first recess and a second recess in the cap substrate; and

forming an outgassing layer over a bottom of the first recess, wherein after the cap substrate is bonded with the MEMS substrate, the first recess forms a portion of the first closed chamber, and the second recess forms a portion of the second closed chamber.

19. The method for forming a MEMS device as claimed in claim 16, wherein the cap substrate comprises a complimentary metal-oxide-semiconductor (CMOS) substrate with a dielectric layer, and the dielectric layer is in the first closed chamber after the first closed chamber is formed.

20. The method for forming a MEMS device as claimed in claim 19, further comprising:

forming a gas-blocking layer to partially cover the dielectric layer before the cap substrate is bonded with the MEMS substrate, wherein the gas-blocking layer is between the dielectric layer and the second closed chamber after the cap substrate is bonded with the MEMS substrate.