Exposure method, exposure apparatus, and device manufacturing method

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 to expose the substrate, the apparatus comprising

• a control unit configured to determine a target effective light source distribution corresponding to a target line width difference based on correlation information indicating a correlation between the effective light source distribution and a line width difference in a pattern formed on a substrate by exposure, and to control the adjusting mechanism so as to obtain the determined target effective light source distribution, and
• a measurement device which measures the effective light source distribution,
• 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 control unit performs:
• obtaining a rate of change in the ratio to an amount of adjustment by the adjustment mechanism;
• determining an amount of adjustment by the adjustment mechanism based on (a) a ratio between a light quantity of the effective light source distribution in the first direction measured by the measurement unit and a light quantity of the effective light source distribution in the second direction measured by the measurement unit, (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.

A device manufacturing method comprising the steps of:

• adjusting an effective light source distribution of an exposure apparatus,
• exposing a substrate using the adjusted exposure apparatus;
• and
• developing the substrate,
• the 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 adjusting step 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;
• and
• 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,
• 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.