In situ plasma wafer bonding method

• US 6,908,832 B2
• Filed: 10/06/2003
• Issued: 06/21/2005
• Est. Priority Date: 08/29/1997
• Status: Expired due to Fees

• Current Assignee: Silicon Genesis
• Original Assignee: Silicon Genesis
• Inventors: Farrens, Sharon N., Roberds, Brian E.
• Primary Examiner(s): PERT, EVAN T
• Application Number:
  US10/680,874
• Publication Number:
  US 20040132304A1
• Time in Patent Office: 624 Days
• Field of Search: 438455-459, 438/798, 438/DIG.974, 204/193, 156/349, 156/379.6
• US Class Current: 438/455
• CPC Class Codes: H01L 21/187 by direct bonding
• CPC Class Codes: H01L 2224/8319 Arrangement of the layer connectors prior to mounting
• CPC Class Codes: H01L 2224/8385 using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 2224/83894 Direct bonding, i.e. joining surfaces by means of intermolecular attracting interactions at their interfaces, e.g. covalent bonds, van der Waals forces
• CPC Class Codes: H01L 24/26 Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H01L 25/50 Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01015 Phosphorus [P]
• CPC Class Codes: H01L 2924/01018 Argon [Ar]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01023 Vanadium [V]
• CPC Class Codes: H01L 2924/01031 Gallium [Ga]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01039 Yttrium [Y]
• CPC Class Codes: H01L 2924/01049 Indium [In]
• CPC Class Codes: H01L 2924/01072 Hafnium [Hf]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01077 : Iridium [Ir]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/0132 : Binary Alloys
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/10329 : Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/30105 : Capacitance
• CPC Class Codes: H01L 2924/3512 : Cracking

Abstract

A method for chemically bonding semiconductor wafers and other materials to one another without exposing wafers to wet environments, and a bonding chamber for in situ plasma bonding are disclosed. The in situ plasma bonding chamber allows plasma activation and bonding to occur without disruption of the vacuum level. This precludes rinsing of the surfaces after placement in the chamber, but allows for variations in ultimate pressure, plasma gas species, and backfill gases. The resulting bonded materials are free from macroscopic and microscopic voids. The initial bond is much stronger than conventional bonding techniques, thereby allowing for rougher materials to be bonded to one another. This bonded materials can be used for bond and etchback silicon on insulator, high voltage and current devices, radiation resistant devices, micromachined sensors and actuators, and hybrid semiconductor applications. This technique is not limited to semiconductors. Any material with sufficiently smooth surfaces that can withstand the vacuum and plasma environments may be bonded in this fashion.

Claims

1. A method for plasma bonding of semiconductor substrates, the method comprising:

transferring a first substrate and a second substrate from a cassette to a plasma chamber equipped with a bonding apparatus, the first substrate having a first face and the second substrate having a second face;

mechanically supporting the first substrate and the second substrate;

maintaining the first substrate and the second substrate in a predetermined environment in the plasma chamber;

exposing at least the first face or at least the second face to a plasma sustained in the plasma chamber; and

releasing the first substrate to initiate a bond between the first face and the second face by contacting at least the first face with the second face.

2. The method of claim 1 wherein said plasma comprises hydrogen bearing species.

3. The method of claim 1 wherein said plasma comprises an oxygen bearing species.

4. The method of claim 1 wherein said plasma comprises an argon with hydrogen.

5. The method of claim 1 wherein said plasma comprises an NH4 bearing species.

6. The method of claim 1 wherein the first face comprises an insulating material.

7. The method of claim 1 wherein the second face comprises an insulating material.

8. The method of claim 1 further comprising rinsing and drying the first substrate and the second substrate before the transferring of the first substrate and the second substrate into the plasma chamber.

9. The method of claim 1 wherein the plasma reduces a surface species of at least the first face or at least the second face.

10. The method of claim 1 wherein the predetermined environment is at least a vacuum.

11. A method for in-situ plasma bonding of semiconductor substrates, comprising:

transferring a first substrate and a second substrate from a cassette to a plasma chamber, the first substrate having a first face and the second substrate having a second face;

maintaining the first substrate and the second substrate in a predetermined environment in the plasma chamber;

exposing at least the first face or at least the second face to a plasma within the plasma chamber;

placing the first face in contact with the second face using a bonding apparatus to initialize a bond between the first face and the second face in the plasma chamber; and

removing the bonded first substrate and the second substrate from the plasma chamber.

12. The method of claim 11 wherein said plasma comprises hydrogen bearing species.

13. The method of claim 11 wherein said plasma comprises an oxygen bearing species.

14. The method of claim 11 wherein said plasma comprises an argon with hydrogen.

15. The method of claim 11 wherein said plasma comprises an NH4 bearing species.

16. The method of claim 11 wherein the first face comprises an insulating material.

17. The method of claim 11 wherein the second face comprises an insulating material.

18. The method of claim 11 further comprising rinsing and drying the first substrate and the second substrate before the placing step.

19. The method of claim 11 wherein the plasma reduces a surface species of the first face and the second face.

20. The method of claim 11 wherein the predetermined environment is at least a vacuum.

21. A method for in-situ plasma bonding of semiconductor substrates, comprising:

placing a first substrate and a second substrate into a plasma chamber, the first substrate having a first face and the second substrate having a second face;

mechanically supporting the first substrate and the second substrate;

maintaining the first substrate and the second substrate in a predetermined environment in the plasma chamber;

exposing at least the first face or at least the second face to a plasma; and

releasing the first substrate to allow the first face to be in contact with the second face to initialize a bond between the first face and the second face in the plasma chamber.

22. The method of claim 21 wherein said plasma comprises hydrogen bearing species.

23. The method of claim 21 wherein said plasma comprises an oxygen bearing species.

24. The method of claim 21 wherein said plasma comprises an argon with hydrogen.

25. The method of claim 21 wherein said plasma comprises an NH4 bearing species.

26. The method of claim 21 wherein the first face comprises an insulating material.

27. The method of claim 21 wherein the second face comprises an insulating material.

28. The method of claim 21 further comprising rinsing and drying the first substrate and the second substrate before the placing of the first substrate and the second substrate into a plasma chamber.

29. The method of claim 21 wherein the plasma reduces a surface species of the first face and the second face.

30. The method of claim 21 wherein the predetermined environment is at least a vacuum.

31. Apparatus for in-situ bonding of substrates, the apparatus comprising:

a plasma chamber;

a cassette configured to hold substrates;

a bonding apparatus provided within the plasma chamber; and

a plasma environment provided within the plasma chamber, the plasma environment being adapted to expose at least a first face of a first substrate or at least a second face of a second substrate to a plasma of the plasma environment;

whereupon the bonding apparatus causes at least the first face to initiate contact with the second face within the plasma chamber to initiate a bond between the first face of the first substrate and the second face of the second substrate.

32. Apparatus of claim 31 wherein the plasma reduces a surface species of at least the first face or the second face.

33. Apparatus of claim 31 wherein at least the first face or at least the second face comprises an oxide layer thereon.

34. Apparatus of claim 31 wherein said plasma is derived from hydrogen bearing species.

35. Apparatus of claim 31 wherein said plasma is derived from an oxygen bearing species.

36. Apparatus of claim 31 wherein said plasma is derived from an argon with hydrogen.

37. Apparatus of claim 31 wherein said plasma is derived from an NH4 bearing species.