Stretchability enhancement of electronics according to the surface patterns fabricated by thermal reflow process

Fabricating flexible and stretchable substrate for circuits is very important to make biomedical devices like biosensors or neural prosthesis. In this paper, the resistance changes of the polydimethylsiloxane (PDMS) film are observed when it is stretched. And the stretchability is measured and classified according to the shape of the engraved patterns. Patterns are fabricated on Si wafer by lithography. Thermal reflow process is conducted to modify the shape of the tips and we used spin coating method to make thin PDMS film. PDMS film is cut into uniform small pieces and stretched at a constant rate by the syringe pump. The resistance of the film is measured while film is stretched. According to the curvature and depth of the groove on the surface, the degree of the improvement varies. The deeper and round patterns enhance the stretchability of the film but sharp and shallow patterns degrade it.