FILM INDUCED INTERFACE ROUGHENING AND METHOD OF PRODUCING THE SAME

• US 20160115016A1
• Filed: 03/24/2015
• Published: 04/28/2016
• Est. Priority Date: 09/11/2014
• Status: Active Grant

• Current Assignee: Invensense Incorporated (TDK Corporation)
• Original Assignee: Invensense Incorporated (TDK Corporation)
• Inventors: Liu, Fang, Lim, Martin, Shin, Jongwoo, Shin, Jong Il
• Granted Patent: US 9,611,133 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: B81C 2201/115 Roughening a surface
• CPC Class Codes: B81C 2203/0792 Forming interconnections between the electronic processing unit and the micromechanical structure

Abstract

Various embodiments provide for a method for roughening a surface of a MEMs device or the surface of a CMOS surface. A first material can be deposited in a thin layer over a surface made of a second material. After heating, the first and second materials, they can partially melt and interdiffuse, forming an alloy. The first material can then be removed and the alloy is removed at the same time. The surface of the second material that is left behind has then been roughened due to the interdiffusion of the first and second materials.

Claims

1. A method for roughening a surface, comprising:

layering a first material over the surface of a second material, wherein the first material and the second material are different materials;

interdiffusing a portion of the first material and the second material at a predetermined temperature; and

removing the first material, wherein the surface of the second material is roughened in response to removing the first material.

2. The method of claim 1, wherein the first material is germanium and the second material is silicon.

3. The method of claim 1, wherein the first material is aluminum and the second material is silicon.

4. The method of claim 1, wherein the first material is aluminum and the second material is germanium.

5. The method of claim 2, further comprising:

patterning the germanium on an interconnect point for bonding to a wafer.

6. The method of claim 5, wherein the wafer comprises electronic circuits.

7. The method of claim 3, further comprising:

depositing germanium on an interconnect point of the surface of the second material and patterning the germanium for bonding to a wafer.

8. The method of claim 4, further comprising:

depositing germanium on an interconnect point of the surface of the second material and patterning the germanium for bonding to a MEMs wafer.

9. The method of claim 1, further comprising:

patterning the second material, wherein the first material is layered after the patterning of the second material.

10. The method of claim 1, further comprising:

heating the first material and the second material to the predetermined temperature.

11. The method of claim 2, further comprising:

heating the first material and the second material to at least 700°

C.

12. The method of claim 3, further comprising:

heating the first material and the second material to at least 600°

C.

13. The method of claim 4, further comprising:

heating the first material and the second material to at least 400°

C.

14. The method of claim 1, further comprising:

heating the first material and the second material for a predetermined length of time.

15. A method to roughen a surface, comprising:

depositing a film of germanium over a silicon surface;

heating the germanium and the silicon surface to a predetermined temperature, wherein a portion of germanium and a portion of silicon are interdiffused, forming a germanium/silicon alloy; and

removing the film of germanium.

16. The method of claim 15, wherein the germanium/silicon alloy is removed with the film of germanium.

17. The method of claim 15, wherein the germanium and the silicon surface are heated to at least 700°

C.

18. The method of claim 15, further comprising:

patterning the germanium on an interconnect point for bonding to a wafer.

19. The method of claim 18, wherein the bonding is achieved by a eutectic bond between the germanium and aluminum on another wafer.

20. A method to roughen a surface, comprising:

depositing a film of aluminum over a silicon surface;

heating the aluminum and the silicon surface to a predetermined temperature, wherein a portion of the aluminum and a portion of silicon at a boundary layer between the film and the silicon surface melt at the predetermined temperature;

annealing the portion of aluminum and the portion of silicon wherein the portion of aluminum and the portion of silicon are interdiffused forming an aluminum/silicon alloy; and

removing the film of aluminum, wherein the aluminum/silicon alloy is removed with the film of aluminum.

21. The method of claim 20, wherein the aluminum and the silicon surface are heated to at least 600°

C.

22. The method of claim 20, further comprising:

depositing a layer of germanium over an interconnect point; and

patterning the germanium on the interconnect point for bonding to a MEMs wafer.

23. A method to roughen a surface, comprising:

depositing a film of aluminum over a germanium surface;

heating the aluminum and the germanium surface to a predetermined temperature, wherein a portion of the aluminum and a portion of germanium at a boundary layer between the film and the germanium surface melt at the predetermined temperature, wherein the portion of aluminum and the portion of germanium are combined forming a aluminum/germanium alloy; and

removing the film of aluminum.

24. The method of claim 23, wherein the aluminum/germanium alloy is removed with the film of aluminum.

25. The method of claim 23, wherein the aluminum and the germanium surface are heated to at least 400°

C.

26. The method of claim 23, wherein the germanium is deposited over a silicon substrate.

27. The method of claim 26, where the silicon substrate comprises electronics circuit.

28. The method of claim 23, wherein the germanium is deposited over a patterned silicon nitride layer.