Performance Improvements for Generating Detailed Blockages

If you are creating Detailed blockages for layouts that have big blockages at the top level, you can gain considerable performance benefits by the use model described here.

This use model is implemented only if the geometry specification (see the criteria below) for a blockage layer is such that the top-level shapes that satisfy the geometry specification are not excluded when the same geometry specification is applied at all the levels. In such a situation, the shapes are processed in the following way:

• At the top level, shapes satisfying the geometry specification and that are bigger than 10 percent of the total cell area are considered as “big blockages”.
• At the lower levels, shapes on the boundary purpose and that are bigger than 10 percent of the total cell area are considered as “big blockages”.

After the “big blockages” are identified, they are processed in the same way as Cover blockages. This use model greatly reduces the complexities of processing and merging shapes and also reduces the number of shapes that are ultimately processed for blockage creation.

Use the BlockageLargeShape option to enable Abstract Generator to look for big blockages in the current design. The BlockageLargeShape option is always used in association with the BlockageLargeShapePct option. The size of the identified blockages is increased by the percentage specified by the BlockageLargeShapePct option, and a cover blockage is created.

Use the BlockageLargePurposeList option to specify the purpose of the identified big blockages.

Use the following criteria for writing a valid geometry specification:

• Geometry specifications with a single purpose:
  • The boundary purpose should be specified explicitly. For example,
    

    M1 boundary

  • If any purpose other than the boundary purpose is specified, there should be no value specified in the Ignored Purpose(s) field (File – General Options – General tab). For example,
    

    M1 net

    M1 drawing

• Geometry specifications with more than one purpose:
  • The boundary purpose should be specified along with the other purpose(s) by using only the OR operator. For example,
    

    M1 boundary or M1 drawing

  • If any combination of LPPs excluding the boundary purpose is specified, there should be no value specified in the Ignored Purpose(s) field (File – General options – General tab). For example,
    

    M1 net or M1 drawing

Related Topics

Running step Abstract Form

Modifying Blockage Geometry in the Abstract View

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