The distortions that arise from thermal stresses in X-ray masks which employ the embedded absorber structure are modelled and analyzed. By using a quasi two-dimensional model, both in-plane and out-of-plane distortions were characterized and their dependence on the fractional absorber coverage was calculated. These distortions were found to be large when the absorber was initially deposited at a high temperature; however they can be greatly reduced by adding a buffer layer between the absorber and membrane. The Young's modulus and the linear expansion coefficient of this buffer layer are chosen such that the mask distortions are compensated for. Without the buffer layer, the shear and peeling stresses at the absorber-membrane interface were found to increase exponentially with distance near the absorber edges and may cause fatigue. These results were found in agreement with computer simulations.

Date Published: 1 May 1990
PDF: 11 pages
Proc. SPIE 1263, Electron-Beam, X-Ray, and Ion-Beam Technology: Submicrometer Lithographies IX, (1 May 1990); doi: 10.1117/12.20162

Published in SPIE Proceedings Vol. 1263:
Electron-Beam, X-Ray, and Ion-Beam Technology: Submicrometer Lithographies IX
Douglas J. Resnick, Editor(s)