Xref: utzoo comp.lsi:461 sci.electronics:2930 Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!pyramid!decwrl!stark From: stark@decwrl.dec.com (Don Stark) Newsgroups: comp.lsi,sci.electronics Subject: Re: (In)correct Parasitic Extraction Message-ID: <435@bacchus.DEC.COM> Date: 10 May 88 04:18:42 GMT References: <2151@obiwan.mips.COM> Organization: Digital Equipment Corporation Lines: 22 Keywords: LPE fringing-capacitance MOS Summary: Take a look at magic In article <2151@obiwan.mips.COM> mark@mips.COM (Mark G. Johnson) writes: > >Why? We need to distinguish between a poly edge and a metal-2 edge, >but the L.P.E. software can't tell them apart. > Magic does what you're looking for. Instead of finding the intersection between metal2 and polysilicon, it looks at each polysilicon/space edge, and sees if it overlaps metal2. If it does, a poly-edge-over-metal2 cap is added. Metal2-space edges are likewise checked to see if they are over polysilicon; if so, a metal2-edge-over-poly cap is added. This is fast and easy to do in a tiled database, but considerably more difficult if you're just sorting polygons and finding their intersection. I think Walter Scott's paper on the circuit extractor contains more details: Walter S. Scott and John K. Ousterhout, "Magic's Circuit Extractor", Proceedings of the 22nd Design Automation Conference, 1985, 286-292. Don Stark Stanford University stark@bill-the-cat.stanford.edu