Fast and Simplified Technique of Proximity Effect Correction for Ultra Large Scale Integrated Circuit Patterns in Electron-Beam Projection Lithography

Abstract

The pattern shape modification method is an effective proximity effect correction technique for electron-beam projection lithography (EPL) systems. We used two characteristics based on the large difference between the forward and backscattering ranges of incident electrons from the 100 kV EPL system to simplify and speed up the pattern shape modification method. The first characteristic is that the amount of pattern bias becomes almost identical on opposite sides of a sufficiently small pattern compared to the backscattering range. The second characteristic is that although the equations for calculating the amount of pattern bias are simultaneous equations, they can be solved separately if the pattern is sufficiently long compared to the forward-scattering range. In addition, multithreading was used to perform parallel processing for the purpose of speeding up the pattern shape modification method. This simplification and speeding up cut the processing time to 1/3 when using four processors. We also checked the correction accuracy by repetition, and considered the use of a correction that maintains the hierarchy for compressing the amount of data.