A novel fabrication process of 3-D microstructures by double exposure in standard deep X-ray lithography

This paper reports a novel fabrication process of 3 dimensional (3-D) micro structures by double X-ray exposure in standard deep X-ray lithography (DXL). The proposed fabrication process made it possible to realize 3-D microstructures with an inclined and curved sidewall without any apparatuses and difficult process control. In order to demonstrate the feasibility of the double X-ray exposure technique, a micro-needle array fabrication was carried out. The sharp micro-needle array with the top radius of less than 100 nm was easily and successfully fabricated by the double X-ray exposure method.