Metallic thin-film bonding and alloy generation

• US 9,383,143 B2
• Filed: 09/25/2014
• Issued: 07/05/2016
• Est. Priority Date: 09/26/2013
• Status: Expired due to Fees

• Current Assignee: Micro Cooling Concepts, Inc.
• Original Assignee: Micro Cooling Concepts, Inc.
• Inventors: Fryer, Jack Merrill, Campbell, Geoff, Peotter, Brian S., Droppers, Lloyd
• Primary Examiner(s): STONER, KILEY SHAWN
• Application Number:
  US14/497,113
• Publication Number:
  US 20150083369A1
• Time in Patent Office: 649 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B23K 20/002 specially adapted for particular articles or work B23K20/129 takes precedence
• CPC Class Codes: B23K 20/02 by means of a press ; Diffusion bonding B23K20/001, B23K20/04 take precedence
• CPC Class Codes: B23K 20/023 Thermo-compression bonding
• CPC Class Codes: B23K 20/026 with diffusion of soldering material
• CPC Class Codes: B23K 20/24 Preliminary treatment
• CPC Class Codes: B23K 2101/14 Heat exchangers
• CPC Class Codes: B23K 2103/10 Aluminium or alloys thereof
• CPC Class Codes: F28D 1/0308 the conduits being formed by paired plates touching each other F28D1/0358 takes precedence
• CPC Class Codes: F28F 19/06 of metal
• CPC Class Codes: F28F 21/084 from aluminium or aluminium alloys
• CPC Class Codes: F28F 2275/061 by diffusion bonding
• CPC Class Codes: F28F 3/086 having one or more openings therein forming tubular heat-exchange passages
• CPC Class Codes: Y10T 137/8593 Systems

Abstract

Diffusion bonding a stack of aluminum thin films is particularly challenging due to a stable aluminum oxide coating that rapidly forms on the aluminum thin films when they are exposed to atmosphere and the relatively low meting temperature of aluminum. By plating the individual aluminum thin films with a metal that does not rapidly form a stable oxide coating, the individual aluminum thin films may be readily diffusion bonded together using heat and pressure. The resulting diffusion bonded structure can be an alloy of choice through the use of a carefully selected base and plating metals. The aluminum thin films may also be etched with distinct patterns that form a microfluidic fluid flow path through the stack of aluminum thin films when diffusion bonded together.

Claims

1. A method of diffusion bonding a stack of aluminum films comprising:

etching a distinct pattern into each of the aluminum films;

plating each of the aluminum films with another metal; and

applying one or both of heat and pressure to the stack of plated aluminum films for a time period sufficient to diffusion bond the films together and achieve a substantially homogenous alloy, wherein the distinct patterns form a microfluidic fluid flow path through the stack of aluminum films.

2. The method of claim 1, wherein the metal plating includes one or more of copper, silver, nickel, manganese, chromium and zinc.

3. The method of claim 1, wherein the aluminum films are each made of an aluminum alloy.

4. The method of claim 1, wherein the distinct patterns etched into the aluminum films form a microstructure within the stack of aluminum films.

5. The method of claim 1, wherein the metal plating forms an oxide at a slower rate than the aluminum films.

6. The method of claim 1, wherein the metal plating forms a less stable oxide than the aluminum films.

7. The method of claim 1, wherein the diffusion bonded films forms an alloy distinct from the aluminum films and the metal plating.

8. The method of claim 1, wherein both heat and pressure is applied to the stack of plated aluminum to diffusion bond the films together.

9. The method of claim 1, wherein decreasing pressure is applied to the stack of plated aluminum films during the diffusion bonding time period.

10. The method of claim 1, wherein increasing heat is applied to the stack of plated aluminum films during the diffusion bonding time period.

11. The method of claim 1, further comprising:

bonding the stack of films to a monolithic metal plate.

12. A method of diffusion bonding a stack of metallic films comprising:

etching a distinct pattern into each of the metallic films;

plating each of the metallic films with another metal;

arranging the etched and plated metallic films in an ordered and aligned stack, wherein the distinct patterns etched into the metallic films forms a microfluidic fluid flow path through the stack of metallic films; and

applying one or both of heat and pressure to the stack of metallic films for a time period sufficient to diffusion bond the metallic films together and achieve a substantially homogenous alloy.

13. The method of claim 12, wherein the metal plating includes one or more of copper, silver, nickel, manganese, chromium, and zinc.

14. The method of claim 12, wherein the metallic films are each made of one or both of aluminum and magnesium.