Patent ID: 7482596
Filing Date: 2009-01-27
Classification: G01N

Abstract:
1. A method for use in optical processing of an article by vacuum UV (VUV) radiation, the method comprising: directing incident VUV radiation propagation from an optical head assembly towards a processing site on the article outside the optical head assembly through a hollow tip-like housing and a gap between the hollow housing and the article, said optical head assembly comprising a sealed unit which contains a VUV non-absorbing medium and is formed with an optical window separating it from said hollow tip-like housing and allowing VUV radiation propagation towards and from the article, the article being located outside of a sealed enclosure, flushing said tip-like housing by a VUV non-absorbing gas by supplying said VUV non-absorbing gas into the tip-like housing through at least one inlet located at a proximal end of the tip-like housing adjacent to the optical window and discharging the VUV non-absorbing gas from the hollow tip-like housing through at least one outlet located at a distal end of the tip-like housing adjacent to the article, thereby providing a flow of said VUV non-absorbing gas along the entire optical path of VUV radiation propagating in between said optical window and the processing site on the article through said hollow housing and the gap, and, a level of the VUV non-absorbing gas in said gap in the vicinity of the processing site is controlled by measuring the reflected VUV radiation.