METAL TRANSFER MICROMOLDING (MTM) PROCESS FOR HIGH-ASPECT-RATIO 3-D STRUCTURES WITH FUNCTIONAL METAL SURFACES

A three-dimensional (3-D) metal transfer micromolding (MTM) fabrication process for low-cost, manufacturable, highaspect-ratio MEMS structures with a patterned metal layer for electrical and biological functionalities is presented in this paper. The mechanism of MTM lies in the differences in adhesion strengths between mold-metal and replica-metal interfaces. This is an extension of a non-covalent 2-D nanotransfer printing (nTP) process and enables a simultaneous replication of high-aspect-ratio 3-D structures from a mold in a single polymer molding process. The conductive layer is patterned at this same step, enabling the resulting structure to have a patterned electrically/biologically functional 3-D metallic layer defined on the high-aspect-ratio polymer structure. This metallic layer on the polymer device has been utilized as a bio-compatible site for cell culturing, an electrode for spontaneous recording from cells and for RF MEMS functionalities. Thus combining the virtues of a conventional micromolding process such as the large-area, high-throughput, and low-cost with simultaneous transfer of patterned metal layer, the MTM process can be applied to a wide range of applications in the chemical, high-frequency, and biomedical areas.

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