Patent ID: 6161054
Filing Date: 2000-12-12
Classification: C23C,H01L

Abstract:
Apparatus for in-line control of a semiconductor wafer fabrication tool, comprising:a Fourier transform infrared reflectometer for measuring, in a fabrication tool, at least one property of each of a series of semiconductor wafers sequentially processed in the tool; andelectronic data processing means operatively connected to said reflectometer for controlling the conditions of processing in the fabrication tool, said data processing means being programmed to perform the functions:(a) store target values for said at least one wafer property that is to be measured;(b) store measured values of said at least one property for a series of wafers processed in sequence in the fabrication tool;(c) compare said measured values to said target value to determine the existence of departures of said measured values from said target value;(d) analyze said departures of values to determine the existence of a trend therein, and to distinguish any such trend from normal statistical variations in the process;(e) relate possible changes of processing conditions in the fabrication tool to resulting changes in the wafer state properties; and(f) based upon the relationship established by said function (e), and said trend of departures of values, as so distinguished, effect such changes in processing conditions as will reduce the departure, from said target value, of said at least one property in wafers subsequently processed in the fabrication tool.