MEMS Structures and Methods for Forming the Same

• US 20130099355A1
• Filed: 10/24/2011
• Published: 04/25/2013
• 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
• Granted Patent: US 9,054,121 B2
• Time in Patent Office: Days
• US Class Current: 257/532
• 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 method comprising:

forming a micro-electro-mechanical system (MEMS) device;

forming a first bond layer adjacent the MEMS device; and

forming a protection layer over the first bond layer, wherein the steps of forming the first bond layer and the protection layer comprise in-situ deposition of the first bond layer and the protection layer.

2. The method of claim 1, wherein the steps of forming the first bond layer and the protection layer comprise:

depositing a blanket metal layer;

depositing a blanket protection layer, wherein the blanket metal layer and the blanket protection layer are deposited in a same process chamber; and

patterning the blanket metal layer and the blanket protection layer to form the first bond layer and the protection layer, respectively.

3. The method of claim 2, wherein between the step of depositing the blanket metal layer and the step of depositing the blanket protection layer, no vacuum break occurs.

4. The method of claim 1 further comprising bonding a cap to cover the MEMS device, wherein during the step of bonding, the protection layer forms a eutectic alloy with the first bond layer.

5. The method of claim 4, wherein during the step of bonding, a second bond layer of the cap forms the eutectic alloy with the protection layer and the first bond layer in a eutectic reaction.

6. The method of claim 1, wherein the protection layer comprises a material selected from the group consisting essentially of germanium, indium, gold, and combinations thereof.

7. The method of claim 1 further comprising:

after the step of forming the protection layer, forming an anti-stiction coating comprising a first portion on a movable element of the MEMS device, and a second portion on the protection layer; and

removing the second portion of the anti-stiction coating, wherein the first portion of the anti-stiction coating is not removed.

8. A method comprising:

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

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

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

depositing a metal layer over the substrate in a process chamber;

depositing a protection layer over the metal layer and in the process chamber, wherein between the step of depositing the metal layer and the step of depositing the protection layer, no vacuum break occurs to the process chamber;

patterning the metal layer and the protection layer to form a bond ring encircling the MEMS device; and

bonding a cap to cover the MEMS device, wherein during the step of bonding, the protection layer forms a eutectic alloy with the bond ring in a eutectic reaction.

9. The method of claim 8, wherein the protection layer is in contact with the metal layer.

10. The method of claim 8, wherein the protection layer is a stacked layer comprising a plurality of layers formed of different materials.

11. The method of claim 8, wherein the cap comprises a bond layer on a surface of the cap, and wherein during the step of bonding, the bond layer of the cap forms the eutectic alloy with the protection layer and the bond layer in the eutectic reaction.

12. The method of claim 11, wherein the bond layer comprises a material selected from the group consisting essentially of germanium, indium, gold, and combinations thereof.

13. The method of claim 12, wherein the protection layer comprises a material selected from the group consisting essentially of germanium, indium, gold, and combinations thereof.

14. The method of claim 8 further comprising:

after the step of forming the protection layer, forming an anti-stiction coating comprising a first portion on the movable element of the MEMS device, and a second portion on the protection layer; and

removing the second portion of the anti-stiction coating, wherein the first portion of the anti-stiction coating is not removed.

15. 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.

16. The device of claim 15, wherein the protection layer is in contact with the bond ring.

17. The device of claim 15, wherein edges of the protection layer are co-terminus with respective edges of the bond ring.

18. The device of claim 15 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.

19. The device of claim 15, 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 15, wherein the protection layer is a stacked layer comprising a germanium layer stacked on an aluminum layer.