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

摘要

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 e.g. a ring-shaped structure with one mask. This so-called 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 said two masks. The method determines all corners of said layout which extend into a hole representing area of said masks. A stability criterion is carried out for said corners, with the consequence that only instable corners are used for cutting said hole representing area into sections. Subsequently said sections are distributed onto said two patterns alternatively.