Patent ID: 8300209

Claim:
A method for exposing a substrate by an exposure apparatus comprising an illumination optical system which is configured to illuminate an original and includes an adjusting mechanism that adjusts an effective light source distribution, and a projection optical system which projects a pattern of the original illuminated by the illumination optical system onto a substrate, the method comprising the steps of: obtaining correlation information indicating a correlation between an effective light source distribution and a line width difference in a pattern formed on a substrate by exposure; determining a target effective light source distribution corresponding to a target line width difference based on the correlation information; controlling the adjusting mechanism so as to obtain the target effective light source distribution determined in the determining step; and exposing the substrate after the controlling step, wherein the line width difference is a difference in line width between a pattern extending in a first direction within a plane of the substrate and a pattern extending in a second direction perpendicular to the first direction within the plane of the substrate, the adjusting mechanism adjusts a ratio between a light quantity of the effective light source distribution in the first direction and a light quantity of the effective light source distribution in the second direction so as to adjust the effective light source distribution, and the step of controlling includes the steps of: obtaining a rate of change in the ratio to an amount of adjustment by the adjustment mechanism; measuring the effective light source; determining an amount of adjustment by the adjustment mechanism based on (a) a ratio between a light quantity of the measured effective light source distribution in the first direction and a light quantity of the measured effective light source distribution in the second direction, (b) a ratio between a light quantity of the target effective light source distribution in the first direction and a light quantity of the target effective light source distribution in the second direction, and (c) the rate of change; and causing the adjustment mechanism to adjust the ratio in accordance with the determined amount of adjustment.