METHOD AND APPARATUS FOR MAINTAINING DESIRED EXPOSURE LEVELS

摘要

TITLE METHOD AND APPARATUS FOR MAINTAINING DESIRED EXPOSURE LEVELS A radiation beam used for selectively exposing a surface is moved in a helical path by means of two oscillating mirrors vibrating about axes that are mutually perpendicular. By maintaining a constant product for oscillating frequency and rotational oscillatory mirror deflection, the level of exposure can be made substantially constant. Case No.: IM-0235