MEMS structures and methods for forming the same

• US 9,533,876 B2
• Filed: 06/05/2015
• Issued: 01/03/2017
• Est. Priority Date: 10/24/2011
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Liu, Ping-Yin, Huang, Xin-Hua, Huang, Hsin-Ting, Hsieh, Yuan-Chih, Peng, Jung-Huei, Chao, Lan-Lin, Tsai, Chia-Shiung, Cheng, Chun-Wen
• Primary Examiner(s): MENZ, DOUGLAS M
• Application Number:
  US14/731,823
• Publication Number:
  US 20150266722A1
• Time in Patent Office: 578 Days
• Field of Search: 257/415
• US Class Current: 1/1
• CPC Class Codes: B81B 3/0005 Anti-stiction coatings
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81B 7/0058 for protecting against damages due to external chemical or mechanical influences, e.g. shocks or vibrations
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 1/00793 Avoid contamination, e.g. absorption of impurities or oxidation
• CPC Class Codes: B81C 2201/053 Depositing a protective layers
• CPC Class Codes: B81C 2203/0109 Bonding an individual cap on the substrate
• CPC Class Codes: H01G 5/16 using variation of distance between electrodes
• CPC Class Codes: H01L 28/60 Electrodes

Abstract

A method includes forming a MEMS device, forming a bond layer adjacent the MEMS device, and forming a protection layer over the bond layer. The steps of forming the bond layer and the protection layer include in-situ deposition of the bond layer and the protection layer.

Claims

1. A device comprising:

a substrate;

a micro-electro-mechanical system (MEMS) device over the substrate, wherein the MEMS device comprises;

a movable element as a first capacitor plate of a capacitor; and

a fixed element as a second capacitor plate of the capacitor;

a bond ring encircling the MEMS device, wherein the bond ring comprises a metal; and

a protection layer over the bond ring, wherein the protection layer is capable of forming a eutectic metal with the bond ring.

2. The device of claim 1, wherein the protection layer is in contact with the bond ring.

3. The device of claim 1, wherein edges of the protection layer are co-terminus with respective edges of the bond ring.

4. The device of claim 1 further comprising a cap comprising a bond layer at a surface, wherein the bond layer comprises a material capable of forming a eutectic alloy with the protection layer and the bond ring, and wherein the cap comprises a ring having substantially a same size as the bond ring.

5. The device of claim 1, wherein the protection layer comprises a material selected from the group consisting essentially of germanium, indium, gold, and combinations thereof, and wherein the bond ring comprises a material selected from the group consisting essentially of aluminum and tin.

6. The device of claim 1, wherein the protection layer is a stacked layer comprising a germanium layer stacked on an aluminum layer.

7. The device of claim 1 further comprising an anti-stiction coating at a surface of the fixed element.

8. The device of claim 7, wherein the anti-stiction coating has an end contacting the protection layer.

9. The device of claim 1 comprising an additional anti-stiction coating at a surface of the movable element.

10. A device comprising:

a substrate;

a micro-electro-mechanical system (MEMS) device over the substrate, wherein the MEMS device comprises;

a movable element as a first capacitor plate of a capacitor; and

a fixed element as a second capacitor plate of the capacitor;

a bond ring encircling the MEMS device, wherein the bond ring comprises a metal, and wherein the bond ring comprises a first inner edge, and a first outer edge encircling the first inner edge; and

a protection layer over the bond ring, wherein the protection layer is capable of forming a eutectic metal with the bond ring, and wherein the protection layer forms a ring with a second inner edge aligned to the first inner edge, and a second outer edge aligned to the first outer edge.

11. The device of claim 10, wherein a bottom surface of the protection layer is in contact with a top surface of the bond ring.

12. The device of claim 10 further comprising a cap comprising a bond layer at a surface, wherein the bond layer comprises a material capable of forming a eutectic alloy with the protection layer, and the cap comprises a ring having substantially a same size as the bond ring.

13. The device of claim 10, wherein the protection layer comprises a material selected from the group consisting essentially of germanium, indium, gold, and combinations thereof, and wherein the bond ring comprises a material selected from the group consisting essentially of aluminum and tin.

14. The device of claim 10, wherein the protection layer is a stacked layer comprising a germanium layer stacked on an aluminum layer.

15. The device of claim 10 further comprising an anti-stiction coating at a surface of the fixed element, wherein the anti-stiction coating covers a first portion of a top surface of the protection layer, and leaving a second portion of the top surface of the protection layer un-covered.

16. The device of claim 15 comprising an additional anti-stiction coating at a surface of the movable element, wherein the anti-stiction coating and the additional anti-stiction coating are formed of a same material.

17. A device comprising:

a substrate;

a micro-electro-mechanical system (MEMS) device over the substrate, wherein the MEMS device comprises;

a movable element as a first capacitor plate of a capacitor; and

a fixed element as a second capacitor plate of the capacitor;

a bond ring encircling the MEMS device, wherein the bond ring comprises a metal;

a protection layer over and contacting the bond ring, wherein the protection layer is capable of forming a eutectic metal with the bond ring, and wherein edges of the protection layer are co-terminus with respective edges of the bond ring; and

an anti-stiction layer comprising;

a first portion covering surfaces of the movable element;

a second portion covering surfaces of the fixed element; and

a third portion covering a first portion of a top surface of the protection layer, with a second portion of the top surface of the protection layer un-covered by the anti-stiction layer.

18. The device of claim 17 further comprising a cap comprising a bond layer at a surface, wherein the bond layer comprises a material capable of forming a eutectic alloy with the protection layer, and the cap comprises a ring having substantially a same size as the bond ring.

19. The device of claim 17, wherein the protection layer comprises a material selected from the group consisting essentially of germanium, indium, gold, and combinations thereof, and wherein the bond ring comprises a material selected from the group consisting essentially of aluminum and tin.

20. The device of claim 17, wherein the protection layer is a stacked layer comprising a germanium layer stacked on an aluminum layer.