Micro‐Casting/Assembly Technology Based on Bismuth‐Based Liquid Metal

Abstract Complex and precise 3D microfabrication technology is the basis for the development of fields including chip‐based bioassay, microelectronic communication, and micromachine manufacturing. Among them, assembled 3D structures provide new ideas to the development of 3D integration of 2D components due to their convenience and high efficiency. In this work, a micro‐casting/assembly technique that can create 3D micro devices is provided with bismuth‐based liquid metal (LM). The liquid metal is first injected into a micro‐mold. The micro‐mold is made by polydimethylsiloxane (PDMS) and porous polycarbonate track‐etched (PCTE) membranes. The mold is then treated with ethanol and deionized water to release the inner injected 2D micro metal components. The effect of each parameter on the generated metal structures is experimentally validated and a LM line with a minimum width of 10 µm is also obtained. For making more functional components, the 2D structures are assembled into 3D. To demonstrate the potential of the technique, reconfigurable micro‐antennas and 3D flow sensors are fabricated and tested at the end of this work, demonstrating potential applications for the micro casting/assembly technology.