| 摘要 |
A photolithographic mask, particularly for VLSI application, is comprised by a patterned liquid crystal panel. A pattern is written on a smectic liquid crystal panel by a laser beam, or by electrical switching. The pattern may be of scattering lines on an optically clear background or of optically clear lines on a scattering background. To write a pattern the laser beam from a source (11) is deflected in a deflection means (13) under the control of a control means (14) and focussed onto a liquid crystal panel (16) for localised heating thereof. The pattern may be subsequently erased, for example by heating the whole panel. Any required pattern may be produced by suitably programming the control means. Such a panel and pattern writing means may comprise a part of a reduction stepper, for example, so that instead of inserting different masks thereinto, different mask patterns are produced therein directly. <IMAGE> |
