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From: R. Timothy Edwards (tim AT stravinsky DOT jhuapl.edu) Date: Thu Jul 10 2003 - 10:22:41 EDT
Dear Prabhat, > I've Magic 7.1 running on Red Hat Linux 7.1 > We are interested in SCN4M_SUBM.20.TSMC process technology. > We've downloaded MTSMS035DL.CIF standard cell library. > Magic starts fine in the desired technology with the following command > magic -T SCN4M_SUBM.20.TSMC.tech27 > Magic also reads in the standard cell library from mtsms035dl.cif file. > But all the cells show errors due to drc violation. The library is > supposed to be correct. Why then does Magic show so many drc errors I will CC this message to the magic discussion email group; I hope you don't mind. This topic has come up before, regarding the mismatch between the standard cell libraries that can be downloaded from MOSIS and the magic technology files. For anyone who doesn't know where the referenced CIF file comes from, it's http://www.mosis.org/Technical/Designsupport/std-cell-library-scmos.html The problem with this library is that most of the contacts have been placed in subcells, such as Cnt_ActM1 or Cnt_PolyM1. The problem is that by placing them in subcells, magic cannot parse them correctly according to the boolean rules it uses to convert CIF to magic layout types. The name of the subcell matches what's in the cell. So, Cnt_PolyM1 contains poly and metal1 and contact. Because magic's cifinput rules for poly contact requires the presence of poly, metal1, and contact, this cell reads in correctly, without errors. HOWEVER, Cnt_ActM1 contains contact, active, and metal1. To magic, this is ambiguous: Magic has at least four contacts that match this description: ndiffusion contact, pdiffusion contact, n-well concact, and p-substrate contact. It is possible to rewrite the cifinput section of the tech file to handle this problem with generic contacts, or you can regenerate the diffusion contacts by hand. This is a perennial problem because I have seen a lot of layout like this---mostly originating from L-Edit, I think---with "floating" contacts in subcells. I will think about a permanent solution to this problem. Regards, Tim
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