Patent ID: 8492058
Filing Date: 2013-07-23
Classification: G03F

Abstract:
1. A method for use in photolithography performed by an exposure apparatus, the method comprising: coating a substrate with a layer of photoresist; exposing the photoresist layer over each of a plurality of shots sequentially by irradiating the photoresist layer to exposure light of the exposure apparatus, wherein the intensity of the exposure light irradiating each shot is different; developing the exposed photoresist layer to form a sample photoresist layer; analyzing an image of the sample photoresist layer to determine the intensity of a color of each shot; selecting one of the shots from among a group of the shots on the developed sample photoresist layer, wherein the group of shots is a series of sequentially exposed ones of the shots over which the intensity of the colors changes from shot to shot; determining the intensity of the color of each pixel within an image of the selected shot; for each assigned the values of the intensity of the color of the pixels, correlating the color intensity value with a value of the intensity of the exposure light to obtain distribution of energy levels of the exposure light during the process of exposing the layer of photoresist; and changing exposure conditions of the exposure apparatus based on the distribution of energy levels of the exposure light determined from the correlation between the color intensity values and the values of the intensity of the exposure light.