Fabrication of sub-micron structures for MEMS using deep X-ray lithography

Fabrication techniques of microstructures with high resolution and high aspect ratio are necessary for practical microelectromechanical systems (MEMS) that have high performance and integration. In order to fabricate microstructures with sub-micron resolution and high aspect ratio, deep X-ray lithography has been investigated using the compact synchrotron radiation (SR) light source called "AURORA". An X-ray mask for sub-micron deep Xray lithography, which is composed of 1 mum thick Au as absorbers, 2 mum thick SIC as a membrane and 625 mum thick Si as a frame, was designed. In preliminary experiments, the following results were achieved: EB resist microstructures with an aspect ratio of 22 corresponding with 0.07 mum width and 1.3 mum height were formed; a 10 mum thick PMMA resist containing no warp was formed by direct polymerization, enabling more precise gap control.