Micro-electro mechanical system (MEMS) device having a blocking layer formed between closed chamber and a dielectric layer of a CMOS substrate

• US 9,487,391 B2
• Filed: 11/19/2013
• Issued: 11/08/2016
• Est. Priority Date: 11/19/2013
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Cheng, Chun-Wen, Chu, Chia-Hua
• Primary Examiner(s): Erdem, Fazli
• Application Number:
  US14/084,161
• Publication Number:
  US 20150137276A1
• Time in Patent Office: 1,085 Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• 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 7/02 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 1/00285 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: B81C 1/00293 maintaining a controlled atmosphere with processes not provided for in B81C1/00285

Abstract

Embodiments of mechanisms for forming a micro-electro mechanical system (MEMS) device are provided. The MEMS device includes a CMOS substrate, a cap substrate, and a MEMS substrate bonded between the CMOS substrate and 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 and a second closed chamber, which are between the MEMS substrate and the cap substrate. The first movable element is in the first closed chamber, and the second movable element is in the second closed chamber. A first pressure of the first closed chamber is higher than a second pressure of the second closed chamber.

Claims

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

a CMOS substrate;

a cap substrate;

a MEMS substrate bonded between the CMOS substrate and 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; and

a second closed chamber between the MEMS substrate and the cap substrate, wherein the second movable element is in the second closed chamber, and a first pressure of the first closed chamber is higher than a second pressure of the second closed chamber; and

a surrounding blocking layer surrounding the first and second closed chambers, wherein the surrounding blocking layer extends towards the CMOS substrate and the cap substrate and surrounds sidewalls of the first closed chamber and the second closed chamber, and the surrounding blocking layer is configured to block gas, coming from the CMOS substrate, from entering the first and second closed chambers.

2. The MEMS device as claimed in claim 1, further comprising a blocking layer between the CMOS substrate and the first and second closed chambers, wherein the blocking layer is configured to block gas, coming from the CMOS substrate, from entering the first and second closed chambers.

3. The MEMS device as claimed in claim 1, wherein the surrounding blocking layer comprises polysilicon.

4. The MEMS device as claimed in claim 2, wherein the blocking layer comprises single crystal silicon.

5. The MEMS device as claimed in claim 1, further comprising a conductive plug penetrating through the surrounding blocking layer and electrically connected to a conductive pad of the CMOS substrate.

6. The MEMS device as claimed in claim 1, further comprising an etch stop layer surrounding the first closed chamber and the second closed chamber.

7. The MEMS device as claimed in claim 6, wherein the etch stop layer comprises silicon nitride, and the etch stop layer has a stress in a range from about −

50 MPa to about 50 MPa.

8. The MEMS device as claimed in claim 1, wherein a ratio of the second pressure to the first pressure is in a range from about 10⁻

11 to about 0.03.

9. The MEMS device as claimed in claim 1, wherein functions of the first movable element and the second movable element are different from each other.

10. The MEMS device as claimed in claim 1, further comprising:

a hole penetrating through the cap substrate; and

a sealing element over the cap substrate, wherein the sealing element covers the hole, and the sealing element is configured to seal the second closed chamber, and the sealing element comprises a metal material.

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

a CMOS substrate;

a first cap substrate;

a second cap substrate bonded with the first cap substrate;

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

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

a second closed chamber between the MEMS substrate and the first cap substrate, wherein the second movable element is in the second closed chamber, and a first pressure of the first closed chamber is higher than a second pressure of the second closed chamber; and

a surrounding blocking layer surrounding the first and second closed chambers, wherein the surrounding blocking layer is configured to block gas, coming from the CMOS substrate, from entering the first and second closed chambers.

12. The MEMS device as claimed in claim 11, wherein a portion of the first closed chamber is between the first cap substrate and the second cap substrate and overlying the second closed chamber.

13. The MEMS device as claimed in claim 11, wherein a ratio of the second pressure to the first pressure is in a range from about 10⁻

11 to about 0.03.

14. The MEMS device as claimed in claim 11, further comprising a blocking layer between the CMOS substrate and the first and second closed chambers, wherein the blocking layer is configured to block gas, coming from the CMOS substrate, from entering the first and second closed chambers.

15. The MEMS device as claimed in claim 11, further comprising an etch stop layer surrounding the first closed chamber and the second closed chamber, wherein the etch stop layer comprises silicon nitride, and has a stress in a range from about −

50 MPa to about 50 MPa.

16. The MEMS device as claimed in claim 11, wherein the surrounding blocking layer comprises polysilicon.

17. The MEMS device as claimed in claim 14, wherein the blocking layer comprises single crystal silicon.

18. The MEMS device as claimed in claim 11, further comprising a conductive plug penetrating through the surrounding blocking layer and electrically connected to a conductive pad of the CMOS substrate.

19. The MEMS device as claimed in claim 11, wherein functions of the first movable element and the second movable element are different from each other.

20. The MEMS device as claimed in claim 11, further comprising;

a hole penetrating through the first cap substrate; and

a sealing element over the first cap substrate, wherein the sealing element covers the hole, and the sealing element is configured to seal the second closed chamber.