Method and apparatus for measurement of exit pupil transmittance

摘要

A method and apparatus for determining the state of the lens transmittance of an optical projection system are described. A lens or imaging objective transmission is determined as a function of exit pupil transverse direction cosine (nx,ny) at multiple field points thereby providing a more complete analysis and correction of a photolithographic exposure system. The entrance pupil of a projection imaging system is uniformly illuminated and the angular dependence of transmission through the imaging system as a function of exit pupil direction cosines is determined. The illumination source includes a light conditioner with an in-situ illumination structure (ISIS), which is an optical structure that can provide uniform illumination of the system's entrance pupil.

主权项

1. A light conditioner comprising:
a reticle having a reticle top surface and a reticle bottom surface; a lens and means for mounting the lens to the reticle; and an aperture plate and means for mounting the aperture plate to the reticle, wherein the lens is mounted above the reticle top surface and substantially focuses on the aperture plate, the aperture plate being attached to the reticle top surface.