| 摘要 |
A method for performing optical lithography is provided. Light is transmitted through a photomask to impinge on a target. The photomask has two mask patterns on two opposing mask surfaces separated by a transparent substrate. Light is transmitted through the first mask pattern and propagates to the second mask pattern, thereby forming a propagation pattern at that location. Light from the propagation pattern is transmitted through the second mask pattern and impinges on the target, thereby creating a target pattern. With this method, the target pattern can be changed without changing either of the mask patterns. Also, this method facilitates gradient exposure of a mask pattern. |
