MEASURING DIFFUSED DISTANCE OF ACID IN PHOTORESIST

摘要

PURPOSE: A method of measuring a diffusion distance of an acid is to use change in the size of a photoresist pattern without special equipment, thereby reducing a manufacturing cost. CONSTITUTION: A photoresist is coated on a lower layer to be formed on a wafer. Using a photomask, the photoresist is exposed. The photomask comprises a measurement mark(100) with an inner box(20) and an outer box(10). Size of the outer box is larger than that of the inner box. Difference of the size is about 1 micrometer. After exposure of the photoresist, a baking process is effected. A photoresist pattern is formed by development of the photoresist. Since the time of heat treat is long, the distance(a) is extended, and the distance(b) is reduced. Therefore, the inner box is shifted toward the outer box. The photoresist pattern is transcribed with the measurement mark. By using an optical equipment such as a CD-SEM(critical dimension scanning electron microscope), an overlay shift of the photoresist pattern is measured.