Rotary vacuum-chuck with venturi formed at base of rotating shaft

摘要

In a first aspect, a rotary vacuum-chuck is provided that may hold a substrate such as a silicon wafer for rotation. The vacuum-chuck includes a hollow rotary shaft and a chuck mounted on the hollow rotary shaft and having a surface adapted to support a substrate. The chuck has one or more openings in fluid communication with the hollow rotary shaft. A venturi is formed near an end of the hollow rotary shaft to apply vacuum to the hollow rotary shaft and the openings in the chuck surface. No seal is required between the end of the hollow rotary shaft and a surrounding stationary block.