MODULAR CELL PLACEMENT SYSTEM WITH FAST PROCEDURE FOR FINDING A LEVELIZING CUT POINT

摘要

A system for defining a cut point dividing a plurality of cells located on the surface of a semiconductor chip is disclosed herein. The surface has at least one region located thereon. The system comprises dividing each region into subregions, computing the capacity of each subregion, finding the maximum and minimum cell locations within each region, dividing the range spanning the maximum and minimum cell locations into a plurality of subintervals, calculating an index for each cell based on the subinterval containing the cell, accumulating cell heights for each subinterval, determining the values of cell heights for each region as the sum of cell heights for all prior regions, locating the minimum index such that the cell heights for each region are most closely proportional to the capacity of the associated subregion, and finding the cut line based on said minimum index and the maximum and minimum cell locations. The system further comprises a calculator which determines an offset of the cut line from the dividing line; a shifter which moves the location of said groups of cells by the offset such that the cut line coincides with the dividing line; and an overflow evaluator and compensator which shifts any cells outside said region to an edge of said region.