| 摘要 |
<p>PURPOSE: To measure superposition precision by one time measurement in the case of superposition of three or more patterns, by forming a mark which has a comb type form in the outer peripheral part, on the IC chip of a wafer, and measuring superposition precision by using the mark. CONSTITUTION: A wafer is moved or an optical system including a mirror 12, a light source 14 and a light receiving apparatus 15 is moved. The wafer is scanned in the Y axis direction, and the tip part li of each comb type tooth is detected and recorded. After that, the wafer is scanned in the X axis direction, and the tip parts of an arbitrary number of comb type teeth to be objective are detected and recorded. In this case, the position of a superposition precision measuring mark can be detected by the difference of reflecting surfaces of light. By using a pattern constituted of a plurality of the comb type teeth, slight superposition deviation can be accurately detected with high precision.</p> |
