US Patent 7676776 Spare gate array cell distribution analysis

A method for determining gate array distribution includes steps or acts of: randomly placing a plurality of test boxes in a logic circuit layout; counting the number of fill cells in each of the plurality of test boxes; recording the count; grouping the plurality of test boxes into two groups: a first group with local clock buffers and a second group without local clock buffers; determining the fill cell percentage of each of the plurality of test boxes; and flagging the test boxes with a poor distribution of gate array cells.