Development of wafer-scale fabrication process of silk fibroin microscale devices

Abstract

This thesis reports the first UV photolithography process on a silk fibroin film using aluminum hard mask. Previously utilized processes on silk fibroin were only applicable on devices with single-layered structure limiting functional versatility because of difficulties on patterning of the substrate and metals with microscale alignment. Thus, fabrication of highly dense electronic components using silk fibroin has been frustrated. In this work, several challenges on previous utilization of UV photolithography have been resolved by introducing aluminum hard mask layer, and developed a set of process for applying UV photolithography on silk fibroin substrates. In turn, verification of process compatibility with silk fibroin was followed. Microscale RC circuits were able to be fabricated on silk fibroin substrate by using the developed process. In addition, highly dense silk-fibroin-based memristors were fabricated. This is the first demonstration of wafer-level fabrication of silk-fibroin-based memristors, and the density of the memory cells has been increased for 100 times from the previously reported one. All of the fabricated silk-fibroin-based devices showed biodegradability in enzymatic solution.