Apparatus and method for projection exposure

A method for projection exposure using a projection optical system which comprises:

• a reflector having first and second reflection surfaces which steer a direction of light rays produced by a light source of an optical system;
• input and output convex lenses which are disposed on both sides of the reflector;
• and
• a reflection compensating optical system for reflecting the light rays, which are reflected by the first reflection surface, back to the second reflection surface;
• the method comprising the steps of:
• when a magnification of the projection optical system is adjusted to be low,
• moving the input and convex lenses so that the input convex lens can recede from the reflector and the output convex lens can come closer to the reflector in a direction of an optical axis while a distance between the input and output convex lenses is kept constant;
• and
• conducting projection exposure,
• when the magnification of the projection optical system is adjusted to be high,
• moving the input and output convex lenses so that the input convex lens can come closer to the reflector and the output convex lens can recede from the reflector in the direction of the optical axis while the distance between the input and output convex lenses is kept constant;
• and conducting projection exposure.

An apparatus for projection exposure which projects a pattern of a mask onto a work comprising:

• a base;
• a source of light for producing light rays carrying ultraviolet light of a predetermined wave length;
• an optical system which constitutes the light rays into projection light rays carrying image information of the mask and guides the projection light rays through a predetermined optical path so that the projection light rays can be projected onto an exposure surface of the work, the optical system comprising:
• a projection optical system which is disposed between the mask support mechanism and the work support mechanism substantially vertically relative to the base;
• and
• an illumination optical system which is disposed between the source of light and the mask support mechanism;
• a mask support mechanism including:
• a mask support frame for vertically supporting the mask relative to the base;
• a mask positioning mechanism which supports and moves the mask support frame within a vertical plane in which the mask is positioned;
• and
• a switching mechanism which supports and slides the mask support frame vertically relative to the base so that a pattern of the mask to be projected can be replaced, and the switching mechanism supporting the mask positioning mechanism;
• a work support mechanism for vertically supporting the work relative to the base so that the exposure surface of the work can coincide with an image forming plane in the optical path;
• and
• an alignment mechanism for adjusting an alignment between the exposure surface of the work and the mask.