| 摘要 |
A measurement device (2) for measuring a collimated wave front through a lithographic lens includes a radiant energy source (4), a lens group (6) for collimating light emitted from said radiant energy source and directing said collimated light (7) toward a reference surface (10). A first binary optic (12) disposed in line with said collimated light and located adjacent to an input conjugate of a lens under test. A second binary optic (18) is arranged in a spaced relationship and in line with said first binary optic for retroreflecting light passing through a lithographic lens disposed between said first and second binary optics. A recording system (8,9) is provided for recording an interference with the light retroreflected-reflected back through said lens and through said reference surface.
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