| 摘要 |
<p>PROBLEM TO BE SOLVED: To make the light control time during scan measurement shorter or constant by measuring the optimum light quantity or gain of each detecting point before making the scan measurement and setting the previously found optimum light quantity or gain at each detecting point at the time of making the scan measurement. SOLUTION: Before making exposure treatment on a wafer 4, light control data are obtained by scanning the wafer 4 by making sample shots with the light from a light source 10 while the illuminance of the light is maintained constantly and receiving reflected light from each detecting point by means of a photoelectric conversion means 19 and a set current value which becomes the optimum peak value for focus exposure during scan exposure is calculated from the obtained data and stored. In the exposure treatment of each shot, the measuring positions are successively illuminated with the set current corresponding to the reflectivity of the measuring positions so as to make the shape (peak) of the waveform to be measured constant regardless of the reflectivity. Therefore, the light control time during scan exposure can be shortened and surface position detection can be performed with higher accuracy.</p> |
