Method of correcting deviations of critical dimensions of patterns formed on a wafer in a EUVL process

Abstract

An embodiment includes a method of correcting deviations of critical dimensions of patterns formed on a wafer in an extreme ultraviolet lithography (EUVL) process. The embodiment includes preparing a reflection photo mask having a reflection layer and absorption patterns that are formed on the reflection layer to define reflection regions therebetween. An exposure process is performed using the reflection photo mask, thereby forming the patterns on the wafer. Critical dimensions of the patterns are measured. A reference critical dimension is set based on the measured critical dimensions of the patterns. Critical dimension deviations are determined by comparing the measured critical dimensions of the patterns with the reference critical dimension. Energy beams having energies corresponding to the critical dimension deviations are locally irradiated onto the reflection layer, thus locally varying the thickness of the reflection layer.

Dependencies are inferred from the claim text.