Projection exposure apparatus and method involving variation and correction of light intensity distributions, detection and control of imaging characteristics, and control of exposure

摘要

In a projection exposure apparatus and method, the intensity distribution of illumination light for detecting an imaging characteristic of a projection optical system is set substantially equal to the intensity distribution of exposure illumination light. The intensity distribution of a secondary light source in an exposure illumination optical system is changed in accordance with a pattern of a mask. Magnification and aberration of the projection optical system are adjusted in accordance with the changed intensity distribution of the secondary light source. A substrate stage is moved along an optical axis of the projection optical system to compensate movement of the image plane of the projection optical system caused by a change in the intensity distribution of the secondary light source. An exposure operation is interrupted when a light amount distribution is changed. Exposure control is also responsive to thermal accumulation in the projection optical system.