• If the vias are aligned, the tool measures edge-to-edge spacing. The tool checks the isolated via spacing first and then checks the isolated via quadrant spacing. If a via fails both tests, it is flagged as an isolated via violation. To fix isolated via violations, run the fix_isolated_via command. By default, the tool fixes the isolated via violations for all unfixed signal, clock, power, and ground nets by inserting a hang-on via (a via that is connected to only one metal layer) on the net. To check for and fix isolated via violations on fixed nets, set the droute_checkFixedDRC variable to 1. In this case, the violations are fixed by adding a via to a unfixed routing segment. To fix isolated via locations that occur on clock nets without touching the clock net itself, set the droute_fixIsoViaTouchClock variable to 0. To fix isolated via violations on power and ground nets without touching the power or ground net itself, set the droute_fixIsoViaTouchPG variable to 0.
Chapter 2: Routing Design Rules Fat Metal Contact Rules 2-66 IC Compiler Technology File and Routing Rules Reference Manual D-2010.03-SP2 IC Compiler Technology File and Routing Rules Reference Manual Version D-2010.03-SP2 Fat Metal Contact Rules The fat metal contact rules are described in the following sections: • Fat Metal Contact Rule • Area-Based Fat Metal Contact Rule • Fat Metal Extension Contact Rule • Area-Based Fat Metal Extension Contact Rule Fat Metal Contact Rule The fat metal contact rule specifies the minimum number of vias required to connect between two metal layers when either of the metal segments is a fat wire. You can specify a fat metal contact rule by using either a one-dimensional or two-dimensional table rule. When you use a one-dimensional table rule, the thresholds are determined by the maximum width of the upper and lower layer metal segments. When you use a two-dimensional rule, you specify separate thresholds for the upper and lower metal layers. You can define a fat metal extension contact rule by specifying an extension threshold for the fat metal contact rule. One-Dimensional Table Rule Note: The newer rule described in “Area-Based Fat Metal Contact Rule” on page 2-68 is preferred to this older rule. Support for this older rule will end in a future release. To define a one-dimensional fat metal contact rule, specify the following attributes in a via Layer section of the technology file: • fatTblDimension Specifies the size of the one-dimensional fat table. • fatTblThreshold Specifies the thresholds used to determine which rules apply, based on the maximum width of the metal segments on the upper and lower metal layers. The width is the smaller of the x-length or y-length of the metal segment. You must specify n values, where n is the table dimension.
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