Direct bonding of copper composites to ceramics

• US 5,490,627 A
• Filed: 06/30/1994
• Issued: 02/13/1996
• Est. Priority Date: 06/30/1994
• Status: Expired due to Fees

• Current Assignee: Hughes Aircraft Company (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Campbell, William T., Krum, Alvin L.
• Primary Examiner(s): Bradley, P. Austin
• Assistant Examiner(s): Knapp, Jeffrey T.
• Application Number:
  US08/268,488
• Time in Patent Office: 593 Days
• Field of Search: 228/124.1, 228/188, 228/198, 228/262.6, 228/262.2
• US Class Current: 228/124.1
• CPC Class Codes: B23K 20/233 without ferrous layer
• CPC Class Codes: B23K 2103/12 Copper or alloys thereof
• CPC Class Codes: C04B 2237/34 Oxidic
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 2237/366 Aluminium nitride
• CPC Class Codes: C04B 2237/407 Copper
• CPC Class Codes: C04B 2237/54 Oxidising the surface before joining
• CPC Class Codes: C04B 37/021 in a direct manner, e.g. direct copper bonding [DCB]
• CPC Class Codes: Y10T 428/12458 having composition, density, or hardness gradient
• CPC Class Codes: Y10T 428/12576 Boride, carbide or nitride component
• CPC Class Codes: Y10T 428/1259 Oxide
• CPC Class Codes: Y10T 428/12611 Oxide-containing component

Abstract

A ceramic member (52) is direct-bonded to a copper composite substrate (58) by heating to diffuse copper to the surface (56) of the copper composite substrate, oxidizing the surface of the copper composite substrate following heating, placing a ceramic member in contact with the resulting oxidized substrate, and forming a copper-copper oxide eutectic (54) at the interface between the copper composite substrate and the ceramic member by heating. The eutectic, upon cooling, forms a bond between the copper composite and the ceramic.

Claims

1. A process for direct bonding a ceramic to a copper composite, said process comprising the steps of:

heating a copper composite substrate to a first temperature at which copper diffuses to a region adjacent the surface of said substrate,

oxidizing said substrate after heating,

placing a ceramic member in contact with the resulting oxidized substrate in an inert atmosphere at a second temperature sufficient to produce a copper-copper oxide eutectic at the interface between said oxidized substrate and said ceramic member, said eutectic, upon cooling, forming a bond between said ceramic and said copper composite.

2. The process of claim 1 wherein the copper composite is selected from the group consisting of copper-tungsten and copper-molybdenum.

3. The process of claim 1 wherein the ceramic is selected from the group consisting of alumina, beryllia, and aluminum nitride.

4. The process of claim 1 wherein the copper composite is copper-tungsten and said first temperature is above about 1200°

C.

5. The process of claim 1 wherein said second temperature is higher than the copper-copper oxide eutectic formation temperature and lower than the melting point of copper.

6. The process of claim 1 wherein said second temperature is within the range of about 1065°

C. to 1083°

C.

7. The process of claim 1 wherein the oxidizing step comprises reacting the diffused copper with an oxidizing agent.

8. The process of claim 7 wherein said oxidizing agent comprises oxygen.

9. A process for direct bonding a ceramic member to a copper-tungsten substrate, said process comprising the steps of:

heating a copper-tungsten substrate to a temperature of about 1200°

C.,

oxidizing said substrate after heating,

placing a ceramic member in contact with the resulting oxidized copper-tungsten substrate in an inert atmosphere at a temperature in the range of about 1065°

C. to 1083°

C. to produce a copper-copper oxide eutectic at the interface between said oxidized copper-tungsten substrate and said ceramic member,

cooling to form a bond between said ceramic member and said copper-tungsten substrate.

10. The process of claim 9 wherein said ceramic is selected from the group consisting of alumina, beryllia, and aluminum nitride.