Patent ID: 6303917
Filing Date: 2001-10-16
Classification: G01J,H01L

Abstract:
An apparatus for monitoring radiant energy generated by a source and delivered through a radiant energy modifying optical element to a substrate without further radiant energy modification, the apparatus comprising:an energy-tapping member disposed intermediate said optical element and said substrate to receive said radiant energy from said optical element, and dividing the received radiant energy into a first portion and a second portion with said first portion passing through said energy-tapping member to said substrate;an energy sensor arranged to receive said second portion of said radiant energy from said energy-tapping member, and to generate a sensor signal; anda processing unit coupled to said energy sensor to receive said sensor signal for comparison with relationship data between said first and second portions of said radiant energy generated during a calibration operation of said apparatus to provide an indication of the radiant energy intensity of said first portion of said radiant energy delivered to said substrate, based on said second portion of said radiant energy.