Prevention of hillock formation during micro-machining of silicon by using OTS-SAM and SiO2 coatings

The feasibility of using a dual coating system consisting of SiO2 and OTS-SAM thin films on the micro-machining characteristics of silicon wafer were investigated with the aim to eliminate the formation of undesirable hillocks. The outermost OTS-SAM coating was used as a sacrificial layer to pattern the SiO2 film, which in turn served to pattern the silicon substrate. After selectively removing the OTS-SAM coating by micro-machining, HF and KOH chemical etching processes followed to remove the SiO2 layer and create patterns on the silicon substrate. By this process, groove patterns of about 1 μm width could be successfully fabricated on a silicon wafer without the formation of undesirable hillocks.