Maskless exposure apparatus using optical modulator, and method for monitoring pattern generating performance by the optical modulator

Abstract

A pattern monitoring method for an exposure apparatus that includes an optical modulator having at least one element that provides incident light with plural phase differences, and a projection optical system that uses first diffracted light among lights exited from the optical modulator to project a pattern onto an object to be exposed includes the steps of detecting second diffracted light having an order different from that of the first diffracted light among the lights exited from the optical modulator, and obtaining a state of the pattern projected onto the object based on a detection result by the detecting step.

Dependencies are inferred from the claim text.