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Magic Mailing List |
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From: Philippe Pouliquen (philippe AT alpha DOT ece.jhu.edu) Date: Fri Sep 05 2003 - 13:19:11 EDT
Tim, > I suggest that you write CIF or GDS, then read it back in, and confirm > that the auto-generated wells comply with the DRC rules (they should). I don't think that the auto-generated wells are guaranteed to pass DRC. Maybe Jeff Sondeen can confirm this, but I think that when you have two N wells that are near one-another but not fully aligned, so that the overlap is less than the minimum well width, the bloat-shrink operation that is supposed to fill in the gap actually creates a narrow bridge. I don't know of any solution to this problem, because widening the bridge can cause a DRV to neighboring N diffusion. The design rules would need to be modified to preclude the N diffusion from being too close to the non-existent N well bridge, and then the CIF rules would need to be modified to create a wide-enough bridge. Here is an example magic file using the SCMOS design rules (the layout if for Magic 6) which exemplifies the problem: magic tech scmos timestamp 1062782013 << ndiffusion >> rect 11 19 15 23 rect 19 2 23 6 << pdiffusion >> rect 25 16 29 20 rect 5 5 9 9 << end >> Just write CIF and read it back in. Philippe
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