A beam of light ( typically ultraviolet light from a mercury arc lamp ) shines through the chromium mask , then passes through a lens that focuses the image onto a photosensitive coating of organic polymer ( called the photoresist ) on the surface of a silicon wafer 一束光(通常是汞弧燈發(fā)出的紫外光)先穿透鉻光罩,然后通過(guò)透鏡把影像聚焦在晶圓表面的有機(jī)高分子感光涂料(稱為光阻劑) 。