Patent ID: 8525973
Filing Date: 2013-09-03
Classification: G03F

Abstract:
1. A method for printing a pattern of features, including the steps of: a) providing a substrate having a recording layer disposed thereon; b) providing a mask bearing at least one of a periodic pattern of features and a quasi-periodic pattern of features; c) arranging the substrate substantially parallel to the mask and with a separation having an initial value; d) providing an illumination system for illuminating the mask with an intensity of substantially monochromatic light to generate a transmitted light-field for exposing the recording layer; and e) illuminating the mask for an exposure time whilst changing the separation by a distance having a desired value and with a rate of change of separation, wherein at least one of the rate of change of separation and the intensity of light is varied over the change of separation so that the mask is illuminated by an energy density per incremental change of separation that varies over said distance; whereby the pattern printed in the recording layer has low sensitivities to a deviation of the distance from the desired value and to the initial value of the separation.