| 摘要 |
PURPOSE:To detect the stabilizing time with excellent precision within minimum time by a method wherein the stabilizing time of airmicrosenser output changing corresponding to the relative positions between an airmicrosenser nozzle and a wafer is properly detected to input any measured values. CONSTITUTION:Voltage output of an airmicrosenser is read by specified frequency at a specified time interval and the mean values thereof i.e. the mean fluctuation is calculated to measure the difference between the former and the latest mean fluctuations successively. If the differences are contained in a specified reference range,a microprocessor, assuming the airmicrosenser to be stabilized, inputs the measured value by the airsenser at that time. The mean fluctuation of output signals is calculated to remove any signal noise. Through these procedures, any focusing point can be measured constantly assuring a specified precision eliminating any waste time. |
