A Low-Cost, Micropattern Transfer Process for Thick-Film Metallization of PDMS

Abstract

We present the detailed characterization of a novel microfabrication process to produce thick-film copper microstructures that are embedded in polydimethylsiloxane (PDMS). This process has reduced fabrication complexity and cost compared to existing metal-on-PDMS techniques and enables rapid prototyping of designs using minimal microfabrication equipment. This technology differs from others in its use of a conductive copper paint seed layer and a unique infrared-assisted transfer process that results in copper microstructures embedded in PDMS. By embedding microstructures flush with the PDMS surface, rather than fabricating the microstructures on the substrate surface, we produce a metallization layer that adheres to PDMS without the need for surface modifications. In addition, the electrodeposition process results in a highly-conductive, thick-film, copper layer. Deposited patterns are shown to be 70-micrometers-thick with reliable feature sizes as small as 100 micrometers. The copper layer has a surface roughness of approximately 5 micrometers and a low film resistivity of approximately 2.5-3 micro-Ω-cm.