Fabrication of HARM structures by deep-X-ray lithography using graphite mask technology

The cost-effective fabrication process for high-aspect-ratio microstructure s using X-rays depends largely on the availability and quality of X-ray mas ks. The fabrication of X-ray masks using commercially available graphite sh eet stock, as a mask membrane is one approach that is designed to reduce co st and turnaround time. Rigid graphite offers unique properties, such as mo derate X-ray transmission, fairly low cost, electrical conductivity, and th e ability to be used with either subtractive or additive processes [1, 2]. This paper will demonstrate the potential of a cost-effective, rapid protot yping of high-aspect-ratio microstructures (HARMs) using graphite masks. Th e graphite wafer accommodates both the intermediate mask and the working ma sk. In order to allow a direct comparison of the graphite mask quality with other X-ray masks, the primary pattern was derived from a Ti X-ray mask us ing soft X-ray lithography (XRL).