Mask creation with hierarchy management using cover cells

摘要

A method and apparatus for translating a hierarchical IC layout file into a format that can be used by a mask writer that accepts files having a limited hierarchy. Cover cells of the original IC layout file or a modified file are designated, and the hierarchical file is redefined to include only those designated cover cells. Non-designated cover cells and other geometric data are flattened into the designated cover cells. The hierarchy of the modified file is then redefined to be less than or equal to the hierarchy limit of the mask writing tool.

主权项

1. A method, comprising:
designating a cell in a hierarchical description as a cover cell, the hierarchical description representing hierarchical relationships between cells of an integrated circuit layout; and by a computer, redefining the hierarchical description, wherein:
the redefining reduces the hierarchical depth of at least a portion of the hierarchical description to be no greater than a predetermined depth limit, andthe redefining comprises incorporating data from one or more noncover cells into the cover cell.