Device and procedure to shield a value retention device from harmful influences during the processing of the workpiece.

摘要

An apparatus for shielding a plurality of wafer registration surfaces 14, 30 and a wafer retention stage 26 from depreciative effects of a chemical etching process includes a pair of etching shields 32, 32' that are positioned along an outside edge of a wafer 10. The wafer 10 is registered to the wafer retention stage 26 by the registration surfaces 14, 30. The wafer retention stage 26, and hence the wafer 10, rotates about an axis 36 through the center of the wafer 10. A chemical etching instrument probe 18 is moved, with respect to the wafer 10, along a fixed wafer diameter 34 while the wafer 10 is rotating. The probe 18 is initially positioned above a first etching shield 32' and is moved, with respect to the wafer 10, across the wafer diameter 34 until it reaches a second etching shield 32. Thus, the probe 18 scans the entire surface of the wafer 10 without extending outside the wafer edge to depreciatively effect the wafer retention materials 14, 26, 30. IMAGE