Vacuum chuck having vacuum-nipples wafer support

Abstract

A vacuum chuck is disclosed which has nipples as support structure and for vacuum delivery. In the preferred embodiment, two types of nipples are used: “plain” nipples which provide only support and vacuum nipples which provide support and deliver vacuum to retain the wafer on the chuck. The contact surface of the plain nipples is made smaller than that of the vacuum nipples. The chuck is secured to a stage using special supports which have limited flexibility in two axis with respect to the chuck, so as to prevent warping the chuck. Special vacuum nipples are disclosed which do not deliver vacuum unless the wafer exerts sufficient predetermined pressure on the nipple. The chuck is designed to hold both 200 mm and 300 mm wafers.

Dependencies are inferred from the claim text.