Polymer micromachining based on Cu On Polyimide substrate and its application to flexible MEMS sensor

摘要

As a way of making a variety of flexible MEMS sensors, we developed a process that uses a Cu On Polyimide (COP) substrate as a starting material and sacrificial Cu etching to produce a cavity and electrical feed-through structures on the substrate. The Cu etching characteristics of an iron (II) chloride solution were studied, and the results confirmed that etching in the depth and side directions strongly depended on the mask pattern and the etching time. A strip-shaped flexible thermal sensor was designed on the basis of the obtained etching results. One heater and two temperature sensors were designed for flow and acceleration sensors applications. The sensing metal on the polyimide thin membrane and the feed-through were successfully fabricated on the COP substrate.