| 摘要 |
PURPOSE: A method for preparing a photomask for negative resist is provided, to improve the CD uniformity of mask pattern, to increase the etching selection ratio of a resist and an under light screening film and to reduce exposure time. CONSTITUTION: The method comprises the steps of coating a negative resist(104) on a light transmitting substrate(100) having a light screening film(102); exposing the core region(110, 120) of negative resist of the substrate where a pattern is formed, with an electron beam; exposing the outer edge(130) of the substrate with a stepper; and developing the substrate to remove the unexposed resist, thereby forming the resist pattern of photomask. Preferably the light screening film is formed on the outer edge of the substrate, and the negative resist of the outer edge is exposed by using laser instead of the stepper. |
