发明名称 |
METHOD OF MAKING PHOTOLITHOGRAPHIC MASKS |
摘要 |
A photolithographic mask is made by a computer generated two-dimensional array of light and dark pixels being photoreduced to provide the mask in which the pixels remain resolved. In use the mask is imaged on to a workpiece such that individual pixels are not resolved, thus providing a varying grey scale which closely approximates to a true grey scale. Problems with non-linear response of photographic materials to illumination intensity are avoided. The pixel array is divided up into resolution cells or pixel sub-arrays each providing a respective optical transmission coefficient. The computer assigns each cell a respective pixel pattern appropriate to the respective transmission coefficient. Pixel patterns may be prearranged and stored or computed using a random number generator. Transmission coefficients may be input to the computer as data, or alternatively computed from a mathematical function where the required mask transmission profile corresponds to such a function. |
申请公布号 |
GB2179472(B) |
申请公布日期 |
1989.07.26 |
申请号 |
GB19860019442 |
申请日期 |
1986.08.08 |
申请人 |
THE * SECRETARY OF STATE FOR DEFENCE |
发明人 |
MICHAEL RICHARD * HOULTON;DAVID ROBERT * WIGHT;PHILIP CHARLES * ALLEN |
分类号 |
G03C5/02;G03F1/00;G03F1/54 |
主分类号 |
G03C5/02 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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