Lossless compression algorithm based on dictionary coding for multiple e-beam direct write system

Electron-beam direct-write (EBDW) lithography is an attractive candidate of next-generation lithography in advanced semiconductor processes. The huge data stream bandwidth required for the data delivery path in EBDW systems could seriously deteriorate throughput, which is one of the major deficiencies constraining EBDW lithography from mass production. A lossless electron-beam layout data compression and decompression algorithm is proposed in this paper for 5-bit gray level bitmaps. Compared with the state-of-the-art LineDiff Entropy algorithm, the proposed method averagely improves the compression rate by 18% and achieves more than 7.5 times speedup for decompression.