| 摘要 |
PROBLEM TO BE SOLVED: To raise the productivity and the reliability by comprising means for quickly detecting that contamination deposits on a wafer chuck or a wafer. SOLUTION: Contamination existence judging means 7 is mounted on a controller 5 for controlling a wafer stage 1 or other unit as a software. After the scan exposure begins, this judging means 7 repeats a focus measurement M times and stores the serially obtained focus measured values in the form of an array in a memory. After the scan exposure ends, the judging means 7 computes the difference between an N-th and N+1-th focus measured values and judges, if this value exceeds a predetermined value, that the contamination exists near the measuring point thereof. In this case a user interface 8 displays a message, etc., for alarming this fact. Thus the productivity and the reliability are raised by informing the operator of the existence of the contamination to quickly make required processes. |
