Method for optimizing the geometry of structural elements of a circuit design pattern and method for producing a photomask

A method for optimizing the geometry of structural elements of a pattern of a circuit design to improve optical imaging properties, comprising:

• (a) providing an electronically stored circuit pattern of the circuit design, the circuit pattern comprising a plurality of structural elements;
• (b) providing a plurality of basic patterns, wherein individual ones of the basic patterns comprise a specific number of structural elements in a specific arrangement as geometric primitives;
• (c) iteratively decomposing the circuit pattern into corresponding basic patterns by progressively performing the following for each basic pattern:
• (c1) defining a working region by determining external dimensions of the geometric primitives of the basic pattern;
• (c2) defining a surrounding region that completely surrounds the working region;
• (c3) comparing the basic pattern with parts of the circuit pattern in the working region and examining the surrounding region to determine whether further structural elements lie in the surrounding region;
• and
• (c4) classifying those parts of the circuit pattern in which a match exists with the basic pattern and no structural elements lie in the surrounding region that influence a lithographic projection of the circuit pattern lying in the working region;
• (d) determining further basic patterns based on those parts of the circuit pattern not classified in (c), thus obtaining a fully classified circuit pattern;
• (e) applying a specification for optimizing the geometry of the structural elements of each basic pattern;
• and
• (f) inserting optimized basic patterns into the circuit design to improve of the optical imaging properties of the circuit pattern transferred onto a semiconductor wafer via lithographic projection.