A Multi-Layer Channel Router Using Simulated Annealing

Masahiko TOYONAGA  Chie IWASAKI  Yoshiaki SAWADA  Toshiro AKINO  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E77-A   No.12   pp.2085-2091
Publication Date: 1994/12/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
channel router,  simulated annealing,  layer assignment,  compaction,  

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We present a new multi-layer over-the-cell channel router for standard cell layout design using simulated annealing. This new approach, STANZA-M consists of two key features. The first key feature of our router is a new scheme for simulated annealing in which we use a cost function to evaluate both the total net-length and the channel heights, and an effective simulated annealing process by a limited range to obtain an optimal chnnel wiring in practical time. The second feature of our router is a basic layer assignment procedure in which we assign all horizontal wiring inside a channel to feasible layers by considering the height of channel including cell region with a one dimensional channel compaction process. We implemented our three-layer cannel router in C language on a Solbourne Series 5 Work Station (22 MIPS). Experimental results for benchmarks such as Deutsch's Difficult Example and MCNC's PRIMARY1 channel routing problems indicate that STANZA-M can achieve superior results compared to the conventional routers, and the process times are very fast despite the use of simulated annealing.