| 摘要 |
PURPOSE:To enable the carbon membrane of a mask support hardly warping after film formation to be formed and to obtain an optically superior mask support by forming the carbon membrane on a water warping upward concavely. CONSTITUTION:The wafer 11 is warped upward concavely and the carbon membrane 22 is formed on it, and when the central part of the wafer 11 is removed to leave the surrounding border part, the carbon membrane 22 is made flat by tensile stress, and wrinkling found so far is prevented. To prepare the mask, an X-ray absorbing pattern mask made of tantalum Ta is formed on the membrane 22 by the process same as the conventional one, and the central part of the wafer 11 is etched off to complete the X-ray mask, thus permitting a membrane made of carbon optically superior to the conventional one to be obtained. |
