Device and method for detecting optical performance of beam shaping element

摘要

A detection apparatus and method for testing optical performance of beam shaping element used in ultraviolet lithography machine; The apparatus comprises visible wavelength laser and other optical units placed along the optical axis including, in order from laser side, (a) beam expander lens group, (b) beam splitter, (c) first far field imaging lens, (d) adjustable aperture or (e) CCD image sensor, (f) second far field imaging lens and (g) energy sensor. The detection apparatus is suitable be employed to detect the optical performance of beam shaping element working at any ultraviolet band, and provides the features of low cost, easy operation and quick measurement.

主权项

1. A device for detecting optical performance of a beam shaping element, comprising
a visible wavelength laser having a laser output direction and an optical axis, a beam expander lens group following the visible wavelength laser on the optical axis and on the laser output direction, a beam splitter on the laser output direction and on the optical axis following the beam expander lens group, said beam splitter being inclined at an angle of 45° to the optical axis whereby an incoming laser output is divided into a transmission beam and a reflection beam, a first energy sensor being arranged at a reflection direction of the beam splitter for detecting the reflection beam from the beam splitter, a first far field imaging lens having a front object focal plane and a back image focal plane and being positioned on the optical axis following the beam splitter, a second far field imaging lens being positioned on the optical axis and having a front object focal plane, which is common to the back image focal plane of the first far field imaging lens, and a back image focal plane, an adjustable aperture on the optical axis following the first far field imaging lens, a CCD image sensor being interchangeable with the adjustable aperture through an interchange unit, for detecting a far field optical intensity distribution of the transmission beam, the CCD image sensor having a central obscuration in middle of its photosensitive surface, the interchange unit being arranged at the common focal plane of the first far field imaging lens and the second far field imaging lens for interchanging the CCD image sensor and the adjustable aperture, a second energy sensor on the optical axis and being located at the back image focal plane of the second far field imaging lens for detecting a beam from the second far field imaging lens, wherein the beam shaping element is placed at the front object focal plane of the first far field imaging lens between the beam splitter and the first far field imaging lens, f, the first far field imaging lens and the second far field imaging lens have a same focal length f, a distance between the first far field imaging lens and the second far field imaging lens is 2f; andthe adjustable aperture and the CCD image sensor are interchangeably arranged at the common focal plane of the first far field imaging lens and the second far field imaging lens.