FAST PROTOTYPING AND SMALL VOLUME PRODUCTION OF MICRO­ DEVICES BY HYBRID MOLDS USING HOT EMBOSSING LITHOGRAPHY

In this thesis, a fabrication method of an innovative hybrid master mold used in hot embossing process and the corresponding validation are investigated. The hybrid master mold consists of a layer of SU-8 structure, a thin film of copper metal, and a layer of anti­ sticking chemical. First, the negative SU-8 resist is patterned on a silicon wafer by conventional photolithography to form microstructures. On the patterned SU-8 surface, a nano-scale thin film of copper is deposited to improve the mold thermal behaviors and perform as a seed layer for the following anti-sticking treatment. The reaction of Trichloro(lH,lH,2H,2H-perfluorocty)silane with the oxidized copper layer is the major part of the anti-sticking treatment, growing a monolayer to reduce interaction during de­ embossing operation. The validation of the hybrid mold presents a high ability of prototyping a small volume of micro-devices with well-balanced time/cost consumption. Using the hybrid mold and appropriate hot embossing parameters, PMMA replicas were processed with high accuracy. In addition, the lifetime study of the hybrid mold has shown more than thirty hot-embossing cycles feasible, which is sufficient for the lab- scale application. Comparing with other master mold approaches, this method combines high qualified products with reduced cost and the processing time, benefiting the demand raised in research community