Evaluation of the new OASIS format for layout fill compression

Abstract

A new Open Artwork System Interchange Standard (OASIS) has recently been proposed to replace the GDSII (Graphic Design System II) format. A primary objective of the OASIS format is to enhance the compressibility of layout data. We compare the data compression capability of the full OASIS set of operators with those also present in GDSII, which we refer to as the restricted OASIS format. We measure the compression quality of the OASIS and GDSII operators in two contexts: (1) compressible fill generation, where the fill amounts are specified and compressible fill is then generated; (2) post-fill data compression, where the fill has already been generated and is then compressed. Our experimental results confirm the advantages of the OASIS compression operators: compressed file sizes using the full OASIS format are on average about twice as small as those obtained using the restricted OASIS format. We propose new OASIS-based compression algorithms which outperform industry physical verification tools. We also evaluate the respective merits of the individual repetition operators in OASIS, and suggest possible improvements to the OASIS repetition operators.