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Magic Mailing List |
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From: John Griessen (john_g AT cibolo DOT com) Date: Wed Apr 30 2003 - 13:07:19 EDT
Hello, I've written Dracula wide-space rules from specs and used some and debugged some against the desired real spec, and they are all ad-hoc -- very different from case to case. This may be a non-problem as long as all the same DRC measuring primitive commands are made available with similar names so Dracula rules can be easily mimicked to "pass muster" when big mask charge ante money is at stake. The wide spacing rules, (for inclusion of relief holes in a layer of metal), I have dealt with are two part rules just like was mentioned on this list a while ago. They are measured in one direction from an identified edge, then trigger other conditional measurements at 90 degrees or in the same direction. John Griessen On Wed, 2003-04-30 at 09:55, R. Timothy Edwards wrote: > 2) The widespacing rule is problematic largely because it describes > a discontinuous rule. For all the simple edge-based rules, > moving a piece of layout by 1 unit will increase or decrease the > DRC violation area by 1 unit. With the widespacing rule, moving > or stretching certain pieces of the layout can cause large areas > of DRC violation to suddenly appear or disappear. The main > consequence of this is that there is no single, obvious way to > define a widespacing rule. As far as I am aware, no one has > created a standard definition of the widespacing rule that > covers all possible cases unambiguously (maybe I should go have > a talk with somebody at NIST?). So instead, the implementation > in Dracula is the "de facto standard" except that I have no > idea what that implementation is. We need to either find out > what algorithm Dracula uses or reverse-engineer it from a slew > of test cases. Otherwise, we're going to start getting emails > from annoyed users who found out that their magic layout didn't > pass muster with a vendor.
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