Method of enhancing phase shift masks

Abstract

A mask generation method can enhance clear field phase shift masks using a chrome border around phase 180 regions. An exemplary method involves identifying edges of a 180 degree phase pattern, expanding these edges, and merging the expansions with chrome. An alternative method involves oversizing and undersizing phase 180 data, taking the difference, and merging the difference with chrome. The chrome region on the phase mask can improve mask generation by allowing the chrome on the mask to fully define the quartz etch.

Description

technical field [0001] The present invention relates to integrated circuits and methods of fabrication thereof, and more particularly to generating phase-shifted patterns to improve patterning of gates and other layers, structures, or regions requiring sub-nominal dimensions. Background technique [0002] Semiconductor devices or integrated circuits may contain millions of components such as transistors. Very large integrated (ULSI) circuits may include complementary metal oxide semiconductor (CMOS) field effect transistors (FETs). Despite existing system capabilities and manufacturing processes for millions of IC components on an IC, there is still a need to reduce the feature size of the IC components, thereby increasing the number of components on an IC. [0003] One limitation in achieving downsizing of IC devices is existing lithography capabilities. Lithography The process by which patterns or images are transferred from one medium to another. Existing IC lithograph...

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Problems solved by technology

As such, the patterning of the binary mask may become complex and the fabrication window of this technology may be limited

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