Alignment method

Abstract

An alignment method for use with an exposure apparatus including first and second alignment sensor systems for establishing alignment between a reticle and a wafer. A first one of reticles in a reticle set is loaded on the exposure apparatus and the position of the pattern center of the reticle is determined. At the same time, the position of the detection center of the first alignment sensor system is determined and the baseline amount B.sub.11, which is the distance from the pattern center of the reticle to the detection center of the first alignment sensor system, is determined. Then, the baseline amount B.sub.21 of the second alignment sensor system is determined, and the difference .DELTA.B (=B.sub.21 -B.sub.11) between the baseline amounts is calculated. For any of the second and later ones of the reticles in the reticle set, the baseline amount B.sub.12 of the first alignment sensor system is calculated in the same manner as the above whereas the baseline amount B.sub.22 of the second alignment sensor system is calculated as: B.sub.22 =B.sub.12 +.DELTA.B. Fine alignment procedure is performed by using the second alignment sensor system and based on the baseline B.sub.22 thus calculated, and the pattern of the reticle is printed on each of the shot areas on a substrate by exposure.