FABRICATION OF INTERMEDIATE MASK FOR DEEP X-RAY-LITHOGRAPHY

This paper presents the fabrication of intermediate x-ray mask for dee p x-ray lithography. In order to have working mask with absorbers thic kness larger than 10 mu m, the intermediate mask should have absorbers of 0.7 mu m in thickness. To demonstrate intermediate mask fabricatio n, x-ray zone plates are fabricated on the 1.2 mu m low-stress silicon -rich silicon nitride (SiNx) membrane with the tri-layer Chromium-Tung sten-Chromium (Cr-W-Cr) as the x-ray absorbers. The chromium layers bo th 200 angstroms are used as adhesion and for stress relief. The SiNx film is deposited with low pressure chemical vapor deposition (LPCVD) and the free standing membrane are formed by KOH silicon backside etch ing. With the e-beam Lithography and reactive ion etching, width of 0. 8 mu m of outmost zone of the x-ray zone plates has been achieved on t he membrane, The scanning electron microscopy (SEM) images of the x-ra y zone plates and pictures of intermediate masks are demonstrated.