Patent ID: 7446859
Filing Date: 2008-11-04
Classification: G03D,G03F,H01L

Abstract:
1. An apparatus for reducing contamination in immersion lithography, comprising: a wafer chuck assembly including a wafer chuck configured to hold a semiconductor wafer on a support surface thereof; said wafer chuck having a gap therein, said gap located adjacent an outer edge of the wafer, and said gap containing a volume of immersion lithography fluid therein; and a fluid circulation path configured within said wafer chuck so as to facilitate the radial outward movement of said immersion lithography fluid in said gap, thereby maintaining a meniscus of said immersion lithography fluid at a selected height with respect to a top surface of the semiconductor wafer, said fluid circulation path further comprising an inlet path through which pressurized fluid is introduced, and in communication with said immersion lithography fluid in said gap, and a return path through which excess immersion fluid from said gap is removed therefrom; wherein said chuck further comprises a lip adjacent said gap and an outer channel adjacent said lip, said gap in fluid communication with said inlet path and said outer channel in communication with said return path, wherein excess immersion fluid in said gap travels radially outward from said gap, over said lip, and into said outer channel; and grooves formed within said lip, said one or more grooves configured to permit said immersion fluid to pass between said gap and said outer channel.