Lossless Compression Algorithm for Multiple E-Beam Direct Write Systems
Date Issued
2015
Date
2015
Author(s)
Pai, Yu-Hsuan
Abstract
Recently, electron-beam lithography is one of the candidates to draw custom shapes on the surface of wafer. The primary advantage of electron-beam lithography is that it can draw custom patterns with sub-nm resolution. Once the throughput of electron-beam lithography can be competitive with traditional optical lithography, the electron-beam lithography will be the main stream of the lithography. As the VLSI circuit design getting larger and more complicated. If we want to apply the electron-beam lithography technology for a layout with 26 mm × 33 mm after rasterization with 7-nm pixel size, either we have to compress the bitmap of layout data with compression factor of 329.7 before fabrication and decompress the data inside electron-beam emitters or we need a transmission fiber with transfer bandwidth 105.5 Tbps at least in semi-conductor fabrication. In this thesis, we proposed a more efficient memory-used algorithm to transform the layout data into a 5-bit gray-level bitmap, which is due to the specification of Reflective Electron Beam Lithography (REBL) system proposed by KLA-Tencor Corporation, and also a dictionary-based algorithm to compress the 5-bit gray-level bitmap. We focus on two of the bottlenecks of the electron-beam lithography. First one is the compression ratio and the other one is decompression rate. According to the experimental results, our algorithm has achieved an at least overall 10% higher compression factor and at least 7.5x faster decompression rate in comparison with the LineDiff Entropy published in 2013.
Subjects
electron-beam
lithography
compression
compression ratio
decompression
5-bit gray-level
dictionary-based
Type
thesis
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