US Patent 7725850 Methods for design rule checking with abstracted via obstructions

Methods of treating via obstructions during design rule checking. The method comprises examining the size of the via obstruction with respect to a minimum size and a minimum spacing constraint of a design rule. Based upon the comparison, a neighboring via count for a number of via shapes neighboring the via obstruction may be initialized to equal a positive integer. Based upon the comparison, the via obstruction may be represented with a plurality of smaller via shapes during design rule checking.