New design concepts of the alternating phase-shifting masks (PSMs) are proposed. They enable alternating PSMs to be applied to random patterns that have the least design restrictions and reduced proximity effects. The original design patterns are decomposed into several subpatterns using geometrical operations, so that each subpatterns can be achieved by alternating type PSMs. The possibility of patterning a below 0.3 mu m pitch random interconnect with conventional deep ultraviolet tools is shown.