METALLIC THIN-FILM BONDING AND ALLOY GENERATION

• US 20150083369A1
• Filed: 09/25/2014
• Published: 03/26/2015
• Est. Priority Date: 09/26/2013
• Status: Active Grant

• Current Assignee: Micro Cooling Concepts, Inc.
• Original Assignee: Micro Cooling Concepts, Inc.
• Inventors: Fryer, Jack Merrill, Campbell, Geoff, Peotter, Brian S., Droppers, Lloyd
• Granted Patent: US 9,383,143 B2
• Time in Patent Office: Days
• US Class Current: 165/104.19
• 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 thin films comprising:

plating each of the aluminum thin films with another metal; and

applying one or both of heat and pressure to the stack of plated aluminum thin films for a time period sufficient to diffusion bond the thin films together and distribute the metal plating evenly throughout the thin 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 thin films are each made of an aluminum alloy.

4. The method of claim 1, further comprising:

etching a distinct pattern into each of the aluminum thin films prior to diffusion bonding the aluminum thin films together.

5. The method of claim 4, wherein the distinct patterns etched into the aluminum thin films forms a microfluidic fluid flow path through the stack of aluminum thin films.

6. The method of claim 4, wherein the distinct patterns etched into the aluminum thin films forms a microstructure within the stack of aluminum thin films.

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

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

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

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

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

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

13. The method of claim 1, further comprising:

bonding the stack of thin films to a monolithic metal plate.

14. An aluminum thin film structure comprising:

two or more aluminum thin films compressed together to form a stack of thin films, wherein each of the aluminum thin films is plated with another metal, and wherein each of the aluminum thin films has a distinct etched pattern therein forming a microfluidic fluid flow path through the stack of thin films.

15. The aluminum thin film structure of claim 14, wherein the aluminum thin films are diffusion bonded together.

16. The aluminum thin film structure of claim 14, wherein the metal plating includes one or more of copper, silver, nickel, manganese, chromium, and zinc.

17. The aluminum thin film structure of claim 14, wherein the aluminum thin films are made of an aluminum alloy.

18. The aluminum thin film structure of claim 15, wherein the diffusion-bonded stack of aluminum thin forms an alloy distinct from the aluminum thin films and the metal plating.

19. The aluminum thin film structure of claim 15, wherein the diffusion-bonded stack of aluminum thin films forms one of a micro-fluidic heat exchanger and a micro-fluidic injector.

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

etching a distinct pattern into each of the metallic thin films;

plating each of the metallic thin films with another metal;

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

applying one or both of heat and pressure to the stack of metallic thin films for a time period sufficient to diffusion bond the metallic thin films together and distribute the metal plating evenly throughout the metallic thin films.

21. The method of claim 20, wherein the metal plating includes one or more of copper, silver, nickel, manganese, chromium, and zinc.

22. The method of claim 20, wherein the metallic thin films are each made of one or both of aluminum and magnesium.