| 摘要 |
A ring (11) of pyrex glass or ceramic supports a silicon ring (12) on which a CVD inorganic membrane (13) is grown for supporting a number of mask patterns (14) in an effective pattern region (15). The edge of this region is shielded against irradiation by a band (17), outside which a substantial area (16) of chessboard pattern is formed. Voids within this area (16) are distributed so that its pattern density is equal to that of the centre (15). Deformation of the significant patterns (14) is therefore counterbalanced by the effects of the tensile or compressive forces in the surrounding area (16). |
