Patent ID: 6080517
Filing Date: 2000-06-27
Classification: G03F

Abstract:
A method of projection exposure for exposing a pattern formed on a mask to the surface of a photosensitive substrate by illuminating the mask to project part of the pattern image of the mask onto an exposure field of the photosensitive substrate through a projection optical system as scanning the mask and the substrate in synchronism with each other relative to the projection optical system, comprising the steps of:producing a target position and target tilt data of the exposure field on the photosensitive substrate surface in a direction of an optical axis of the projection optical system;detecting a position in the exposure field on the photosensitive substrate surface in the optical-axis direction of the projection optical system;calculating a first position of the exposure field on the photosensitive substrate in the optical-axis direction and first tilt of the exposure field relative to a plane perpendicular to the optical axis, based on the detected information;determining whether an amount based on at least one of a difference between the first position and the target position and a difference between the first tilt and the target tilt of the exposure field on the photosensitive substrate surface falls within a controllable range of the position of the photosensitive substrate; andcontrolling at least one of the position and the tilt of the photosensitive substrate in such a manner that if the judgment is affirmative, the exposure field on the photosensitive substrate surface is made to correspond with the focal plane of the projection optical system based on the target position and the target tilt data as well as the first position and the first tilt data, and if the judgment is negative, the position of the exposure field in the optical-axis direction is made to correspond with the center position of the focal plane of the projection optical system in the optical-axis direction based on the target position and the first position, with the photosensitive substrate surface being kept at a fixed tilt.