| 摘要 |
PROBLEM TO BE SOLVED: To accurately control the focusing position of a projection lens which is optimum for forming a projection pattern image in the exposure method using an optical stepper in a lithography step for printing a circuit pattern, formed on a reticle to a resist on a wafer. SOLUTION: A focus-detecting rectangular pattern CPa, susceptible to optical proximity effect, is provided on a reticle having an element circuit pattern for a projection pattern image RPa to be formed on a wafer, depending on the change of the exposure conditions. At exposure, the projection pattern image RPa of the focus-detecting pattern CPa is read to obtain its lateral length LxRPa , from which the correction valueΔF for correcting the deviation from the focus position of the projection lens is calculated. Thus a circuit pattern is exposed, while always correcting for the focus deviation of the projection lens.
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