Liquid metal circuits and methods of making the same
Manufacturing technology to fabricate liquid metal-based soft and flexible electronics (sensors, antennas, etc.) in a high-throughput fashion, with fabrication rates that may approach that of the traditional integrated circuit components and circuits, are described. The technique allows creation of liquid-metal-only circuits, as well as seamless integration of solid IC chips into the circuits, in which liquid metal traces are used as flexible interconnects and/or as other circuit elements. The process may be applied at the wafer scale and may be integrated into the traditional microelectronics fabrication processes. Many sensors, antennas, and other circuit elements may be directly created using liquid metal, and when combined with the IC chips, a broad range of electronic functionality may be provided in a flexible, soft circuit that can be conformable, wearable.
1 . A method of manufacturing a liquid metal circuit, the method comprising:
submerging a substrate having an alloying metal pattern on at least a portion thereof into a bath of liquid metal in an oxide-free state for a dwell time to alloy the liquid metal with the alloying metal pattern; and
withdrawing the substrate from the bath at a removal speed to form the liquid metal circuit having a circuit pattern and a deposition height correlated with the removal speed,
wherein the deposition height increases in a log-linear relationship monotonically with removal speed over at least one decade of speed.
2 . The method of claim 1 , wherein the bath of liquid metal is in an oxygen-free environment.
3 . The method of claim 2 , wherein the oxygen-free environment is an argon environment, a nitrogen environment, or combinations thereof.
4 . The method of claim 2 , wherein the bath of liquid metal lacks a reduction agent.
5 . The method of claim 1 comprising depositing the alloying metal on the surface of the substrate.
6 . The method of claim 1 comprising fabricating the alloying metal pattern using photolithography, stencil printing, selective deposition, rolling, or contact printing.
7 . The method of claim 1 comprising agitating the liquid bath when submerging the substrate.
8 . The method of claim 1 comprising positioning a microelectronic component proximate to the liquid metal circuit.
9 . An integrated circuit comprising the liquid metal circuit manufactured according to claim 8 .
10 . The method of claim 1 , wherein the removal speed is from 10 −1 to 10 3 mm/s.
11 . The method of claim 1 , wherein the liquid metal circuit comprises:
a height up to 100 micrometers,
a width up to 500 micrometers, and
a height-to-width ratio from 0.1-100.
12 . The method of claim 1 , wherein the liquid metal circuit has a height-to-width ratio from 0.1-100.
13 . The method of claim 1 , wherein the removal speed is from 10 −1 to 10 3 mm/s, and the liquid metal circuit comprises a height up to 100 micrometers and a height-to-width ratio from 0.1-100.
14 . The method of claim 1 , wherein the substrate comprises a surface area greater than 1 square inch.
15 . The method of claim 1 , wherein the substrate comprises a plurality of the liquid metal circuits.
16 . The method of claim 1 , wherein the alloying metal pattern comprises copper, gold, platinum, palladium, tin, zinc, iridium, or any combinations thereof.
17 . The method of claim 1 , wherein the liquid metal is gallium, indium, tin, or any combinations thereof.
18 . The method of claim 1 , wherein the liquid metal is a gallium-indium alloy or a gallium-indium-tin alloy.
19 . The method of claim 1 , wherein
the removal speed is from 10 −1 to 10 3 mm/s,
the liquid metal circuit comprises a height up to 100 micrometers and a height-to-width ratio from 0.1-100,
the alloying metal pattern is copper, gold, platinum, palladium, tin, zinc, iridium, or any combinations thereof, and
the liquid metal is gallium, indium, tin, or any combinations thereof.