Efficient layout data compression algorithm and its low-complexity, high-performance hardware decoder implementation for multiple electron-beam direct-write systems

Abstract

A lossless electron-beam layout (EBL) data compression algorithm, LineDiff Entropy v2.0, and its lowcomplexity, high-performance hardware decoder for multiple electron-beam direct-write lithography systems are proposed. The algorithm compares consecutive data scanlines and encodes the data based on the change/nochange of pixel values and the lengths of pixel sequences. Then, the compaction steps of data omission, merging, and encoding of consecutive long identical scanlines are applied. Unique short codes are assigned to data with high occurrence frequency. The hardware decoder is designed as three circuit blocks that perform entropy decoding, decompaction, and EBL data generation through parallel outputs. The results demonstrate that our algorithm can achieve excellent compression performance and that the hardware decoder can decompress data at very high data rates.