Patent ID: 7518704
Filing Date: 2009-04-14
Classification: G03F

Abstract:
1. A multiple exposure apparatus comprising: performing a first exposure process by exposing a region of a resist on a substrate to exposure light directed through a reticle; subsequently performing a second or higher order exposure process comprising positioning a second NA controller along the optical axis, illuminating the mask pattern of a reticle with exposure light transmitted along the optical axis using the second NA controller, and exposing said region of the resist to the exposure light transmitted using the second NA controller and directed through the reticle, wherein the reticle used in each of the exposure processes has a mask pattern of features spaced by a first pitch along a short axis, and by a second pitch along a long axis, wherein with the first pitch is shorter than the second pitch, and wherein the first exposure process comprises illuminating the mask pattern of the reticle with exposure light transmitted along an optical axis using a first NA controller that provides a resolution with respect to the direction of the short axis of the mask pattern that is higher than the resolution with respect to the direction of the long axis of the mask pattern, wherein the first NA controller is moved off of the optical axis after the first exposure process has been performed, and wherein the second or higher order exposure process comprises positioning a second NA controller along the optical axis and illuminating the mask pattern of the reticle with exposure light transmitted along the an optical axis using a second NA controller that provides a resolution with respect to the direction of the long axis of the mask pattern that is higher than the resolution provided by the first NA controller with respect to the direction of the long axis of the mask pattern; correlating ratios of exposure latitudes E establishing parameters of the first and the second or higher order exposure processes based on the correlation such that a pattern of a predetermined size will be formed on the substrate.