摘要 |
A processor is provided for an improved semiconductor etching system which generates a series of multi-bit digital output code words. The processor provides an endpoint detector for determining if one of the digital output code word has reached a predetermined endpoint level and for generating a control signal to stop etching of a wafer. The processor further provides a standard endpoint curve corresponding to standard etching of a standard wafer. A normalizer is provided for normalizing the current endpoint curve generated from the series of multi-bit digital code words for a wafer being etched with respect to the standard endpoint curve and for providing a normalized current endpoint curve. A comparator fits and compares the normalized current endpoint curve for a wafer being etched to the standard endpoint curve, where the comparator includes a generator for generating a quality index number for the wafer corresponding to the cumulative area between the normalized current endpoint curve for a wafer being etched and the standard endpoint curve.
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