Microscale Machining and Formation of Micro/Nano Structures using Wet Processes

Abstract

Recent topics on the wet processes to form micro and nano structures for functional applications were introduced. A novel lithography process was developed for nanoscale patterning using electron beam lithography in combination with a resist material, organosilane self-assembled monolayer, which achieved patterning of arrayed nanodots as small as 20 nm in diameter. A photo-assisted Si anodization process to fabricate microscale pore arrays was also described. Using prepatterned array of pits on Si wafer surfaces as initiation sites, electrochemical etching was carried out in aqueous fluoride solution under the illumination from back side of the wafer to form arrays of uniform and high aspect ratio pores at the selected areas. The pore array was used for further modification, to fabricate pL volume SiO2 “test tubes” using surface oxidation and wet etching processes. Metal filling to the pores was also attempted to fabricate a microscale needle array.