Microfluidic channels and pumps for active cooling of circuit boards

• US 10,660,199 B1
• Filed: 10/30/2018
• Issued: 05/19/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Flowers, Jonathan Barak, Mehnert, Herbert
• Primary Examiner(s): Chen, Xiaoliang
• Application Number:
  US16/175,456
• Publication Number:
  US 20200137885A1
• Time in Patent Office: 567 Days
• Field of Search: 174252, 361696, 361698, 361699, 361748, 4352871, 422 681, 422502, 310 11, 310328, 16510429, 16510431, 16510433
• CPC Class Codes: H01B 7/423 using a cooling fluid
• CPC Class Codes: H05K 1/0201 Thermal arrangements, e.g. for cooling, heating or preventing overheating
• CPC Class Codes: H05K 1/0203 Cooling of mounted components H05K1/0272 takes precedence
• CPC Class Codes: H05K 1/0272 Adaptations for fluid transport, e.g. channels, holes
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/09 Use of materials for the conductive, e.g. metallic pattern
• CPC Class Codes: H05K 2201/064 Fluid cooling, e.g. by integral pipes
• CPC Class Codes: H05K 2201/066 Heatsink mounted on the surface of the PCB heatsink inserted in the PCB H05K2201/10416
• CPC Class Codes: H05K 2201/093 Layout of power planes, ground planes or power supply conductors, e.g. having special clearance holes therein reduction of cross-talk, noise or interference by patterned shielding planes, ground planes or power planes H05K1/0224
• CPC Class Codes: H05K 2201/10083 Electromechanical or electro-acoustic component, e.g. microphone

Abstract

Microfluidic channels and pumps for active cooling of circuit boards are described. One circuit board includes a substrate and a microfluidic channel structure disposed on the substrate, the microfluidic channel structure comprising liquid metal disposed in a microfluidic channel. Liquid metal is disposed in the microfluidic channel and a pump pumps the liquid metal through the microfluidic channel to actively cool at least a portion of the circuit board.

Claims

1. A circuit board comprising:

a substrate;

a microfluidic channel structure disposed on the substrate, the microfluidic channel structure comprising liquid metal disposed in a microfluidic channel; and

a pump coupled to the microfluidic channel structure, wherein the pump is to pump the liquid metal through the microfluidic channel to actively cool at least a portion of the circuit board, wherein the microfluidic channel structure is disposed in a ground plane of the circuit board.

2. The circuit board of claim 1, wherein the microfluidic channel structure is a liquid-metal trace.

3. The circuit board of claim 1, further comprising:

inlet tubing coupled to a first end of the microfluidic channel; and

outlet tubing coupled to a second end of the microfluidic channel, wherein the pump is a mechanical pump that mechanically pumps the liquid metal through the microfluidic channel.

4. The circuit board of claim 3, wherein the mechanical pump is a peristaltic/systolic pump.

5. The circuit board of claim 1, wherein the pump is an electrostatic pump that uses an electric field to move the liquid metal through the microfluidic channel.

6. The circuit board of claim 1, wherein the pump is an electromagnetic pump that moves the liquid metal using electromagnetism.

7. The circuit board of claim 1, wherein the liquid metal is a eutectic alloy comprising at least gallium and indium.

8. The circuit board of claim 1, wherein the liquid metal is a Eutectic Gallium Indium (EGaIn) alloy.

9. The circuit board of claim 1, further comprising:

a heatsink disposed at a location on the pump, the heatsink to dissipate heat away from the circuit board at the location on the pump.

10. The circuit board of claim 1, further comprising:

a first heatsink disposed at a first location on the pump, the first heatsink to dissipate heat away from the circuit board at the first location on the pump; and

a second heatsink disposed at a second location on the pump, the second heatsink to dissipate heat away from the circuit board at the second location on the pump.

11. The circuit board of claim 1, wherein the liquid metal is a eutectic alloy or a Eutectic Gallium Indium (EGaIn) alloy, wherein the eutectic alloy comprises at least gallium and indium.

12. An apparatus comprising:

a circuit board comprising;

a substrate;

a component disposed at a first location; and

a microfluidic channel structure disposed on the substrate, the microfluidic channel structure comprising a microfluidic channel formed in at least one of polymeric organosilicon material or thermoplastic polymer material; and

a pump coupled to the microfluidic channel structure, wherein the pump is to pump liquid metal through the microfluidic channel, wherein the liquid metal, when pumped through the microfluidic channel during operation of the component, transfers heat originating from the component at the first location through the microfluidic channel structure to a second location of the circuit board, wherein the microfluidic channel structure is disposed in a ground plane of the circuit board.

13. The apparatus of claim 12, wherein the microfluidic channel structure is a liquid-metal trace.

14. The apparatus of claim 12, further comprising:

inlet tubing coupled to a first end of the microfluidic channel; and

outlet tubing coupled to a second end of the microfluidic channel, wherein the pump is a peristaltic/systolic pump that mechanically pumps the liquid metal through the microfluidic channel.

15. The apparatus of claim 12, wherein the liquid metal is a eutectic alloy comprising at least gallium and indium.

16. The apparatus of claim 12, wherein the liquid metal is a Eutectic Gallium Indium (EGaIn) alloy.

17. An apparatus comprising:

a circuit board comprising;

a substrate;

a component disposed at a first location; and

a microfluidic channel structure disposed on the substrate, the microfluidic channel structure comprising Polydimethylsiloxane (PDMS) and Poly(methyl methacrylate) (PMMA), wherein a microfluidic channel is formed in PMMA; and

a ground plane disposed on a first side of the substrate, wherein the microfluidic channel structure is disposed on a second side of the substrate; and

a via disposed between the ground plane on the first side of the substrate and the microfluidic channel structure on the second side of the substrate; and

a pump coupled to the microfluidic channel structure to move liquid metal through the microfluidic channel, wherein the liquid metal, when pumped through the microfluidic channel during operation of the component, transfers heat originating from the component at the first location through the microfluidic channel structure away from the component at the first location.

18. A circuit board comprising:

a substrate

a microfluidic channel structure disposed on the substrate, the microfluidic channel structure comprising Polydimethylsiloxane (PDMS) and Poly(methyl methacrylate) (PMMA), wherein a microfluidic channel is formed in PMMA; and

a pump coupled to the microfluidic channel structure to move liquid metal through the microfluidic channel to transfer heat away from at least a first portion of the circuit board, wherein the microfluidic channel structure comprises;

a first PMMA layer;

a second PDMS layer; and

a third PMMA layer.

19. The circuit board of claim 18, wherein the liquid metal is a eutectic alloy or a Eutectic Gallium Indium (EGaIn) alloy, wherein the eutectic alloy comprises at least gallium and indium.