Fabrication of complementary patterns for exposing semiconductor chips with self-supporting masks

Abstract From the Canadian patent

For the fabrication of semiconductor chips with an increasing number of electrical elements it is necessary that the geometry of the elements becomes smaller and smaller. For that purpose, lithographic techniques have been developed using x-rays, electron or ion beams. Especially for particle beams self-supporting masks are, stringent with the consequence that it is not possible to fabricate, for example, a ring-shaped structure with one mask. This mask stencil problem is solved by exposing the chip with two complementary masks. The present application relates to a method for automatically splitting one layout into two complementary patterns for the two masks. The method determines all …