Method of removing astigmatism from a wavefront in an aberration measurment system

摘要

Defocus and astigmatism compensation methods for use in an aberration measurement system. The methods including passing a wavefront having defocus through a first lens (120) on a first path, reflecting the wavefront from the first path to a second path, reflecting the wavefront from the second path to a third path, and passing the wavefront through a second lens (122) as a defocus compensated wavefront; and passing a wavefront through first and second cylindrical lens (140A,B), and orienting the first and second cylindrical lenses with respect to the wavefront and to one another to compensate for astigmatism in the wavefront.