Motion Sensor Device and Methods for Forming the Same

• US 20130068023A1
• Filed: 01/18/2012
• Published: 03/21/2013
• Est. Priority Date: 09/16/2011
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Cheng, Shyh-Wei, Wang, Chih-Yu, Chu, Che-Jung, Hsu, Yu-Ting, Hsu, Hsi-Cheng, Weng, Jui-Chun
• Granted Patent: US 8,960,003 B2
• Time in Patent Office: Days
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0871 using stopper structures for limiting the travel of the seismic mass
• CPC Class Codes: H01G 5/16 using variation of distance between electrodes
• CPC Class Codes: Y10T 29/43 Electric condenser making

Abstract

A Micro-Electro-Mechanical System (MEMS) device includes a sensing element, and a proof mass over and overlapping at least a portion of the sensing element. The proof mass is configured to be movable toward the sensing element. A protection region is formed between the sensing element and the proof mass. The protection region overlaps a first portion of the sensing element, and does not overlap a second portion of the sensing element, wherein the first and the second portions overlap the proof mass.

Claims

1. A device comprising:

a Micro-Electro-Mechanical System (MEMS) device comprising;

a sensing element;

a proof mass over and overlapping at least a portion of the sensing element, wherein the proof mass is configured to be movable toward the sensing element; and

a protection region between the sensing element and the proof mass, wherein the protection region overlaps a first portion of the sensing element, and does not overlap a second portion of the sensing element, and wherein the first and the second portions overlap the proof mass.

2. The device of claim 1, wherein the protection region is formed of a material, wherein the material is disposed to regions overlapping a corner region of the proof mass, and wherein none of the material overlaps a center region of the proof mass.

3. The device of claim 1, wherein the protection region is formed of a material, wherein the material is disposed to regions overlapping a corner region of the proof mass, and wherein none of the material overlaps an edge region of the proof mass.

4. The device of claim 1, wherein the protection region has a greater hardness than the sensing element.

5. The device of claim 1, wherein the sensing element comprises aluminum copper, and wherein the protection region comprises a metal nitride.

6. The device of claim 1, wherein the sensing element comprises aluminum copper, and wherein the protection region comprises an oxide or silicon nitride.

7. The device of claim 1, wherein the proof mass comprises silicon.

8. A device comprising:

a Micro-Electro-Mechanical System (MEMS) device comprising;

a sensing element formed of a first conductive material;

a proof mass formed of a second conductive material, wherein the proof mass and the sensing element form a capacitor, and wherein the proof mass is configured to be movable into a space between the proof mass and the sensing element; and

a protection region formed of a material having a greater hardness than the hardness of the sensing element, wherein the protection region is configured to prevent the proof mass from hitting any portion of the sensing element.

9. The device of claim 8, wherein the protection region is located between, and aligned to, the proof mass and the sensing element, and wherein the protection region contacts the sensing element and does not contact the proof mass.

10. The device of claim 8, wherein the first conductive material comprises silicon, and wherein the second conductive material comprises aluminum copper.

11. The device of claim 8, wherein the protection region covers a part, and not an entirety, of the top surface of the sensing element.

12. The device of claim 8, wherein the protection region is formed of a material selected from the group consisting essentially of a metal nitride, an oxide, silicon nitride, and titanium tungsten.

13. The device of claim 12, wherein the protection region comprises titanium nitride.

14. The device of claim 8, wherein at least a portion of the sensing element overlaps the proof mass and is exposed to an air-gap between the sensing element and the proof mass.

15. A device comprising:

a Micro-Electro-Mechanical System (MEMS) device comprising;

a sensing element comprising aluminum;

a proof mass comprising silicon, wherein the proof mass, the sensing element, and an air-gap between the sensing element and the proof mass form a capacitor of the MEMS device; and

a plurality of protection regions in contact with the sensing element and between the sensing element and the proof mass, wherein the plurality of the protection regions overlaps regions selected from the group consisting essentially of edge regions of the proof mass and corner regions of the proof mass, and wherein no protection region is formed to overlap a center region of the proof mass.

16. The device of claim 15, wherein the sensing element comprises aluminum copper, and the proof mass comprises silicon, and wherein the plurality of protection regions has a greater hardness than aluminum copper.

17. The device of claim 15, wherein the plurality of the protection regions overlaps the corner regions of the proof mass.

18. The device of claim 15, wherein the plurality of the protection regions overlaps the edge regions of the proof mass.

19. The device of claim 15, wherein the plurality of the protection regions is formed of a material selected from the group consisting essentially of a metal nitride, an oxide, and titanium tungsten.

20. The device of claim 19, wherein the plurality of the protection regions is formed of titanium nitride.