Method for Producing Biconcave Wafers
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
The barrel etcher is used to remove the damage caused by lapping. After this step, the wafers are polished. Unfortunately, double-side polishing, which is currently used as a standard, degrades the wafer geometry so that the wafers become biconvex. The objective of the present method is to produce biconcave wafers at the barrel-etching operation in order to compensate for the above-mentioned effect, and thus to obtain semiconductor wafers with improved flatness. A first solution might consist in increasing the distance between the spacers; however, this technique drastically reduces productivity. The proposed method consists in using the standard barrel etcher but with special spacers provided with four holes arranged in such a way that they roughly correspond to the center of the wafers (see the figure).