| 摘要 |
An X-ray exposure mask for use in a stepper in X-ray lithography is formed so that deformation of mask patterns on a surface of the X-ray mask is prevented, so that when these patterns are transferred to a semiconductor wafer substantially no deformation of the patterns will occur, allowing higher integration of patterns. The surface of the X-ray mask is divided into a centrally located first region and a surrounding second region. A layer of X-ray absorbing material is superposed on the surface of the X-ray mask and includes a first layer portion coextensive with the first central region and patterned for selectively exposing the first central region of the membrane surface in a corresponding pattern for selected transmission of an X-ray beam therethrough. A second layer portion of the layer of X-ray absorbing material, coextensive with the second, surrounding region of the membrane, is patterned for selectively exposing the second, surrounding region to reduce the density of the X-ray absorbing material on that second, surrounding region. Preferably, the respective densities of the first and second layer portions of the X-ray absorbing material are substantially the same, although a difference of up to 30% therebetween will yield satisfactory results.
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