Method, program product and apparatus for model based scattering bar placement for enhanced depth of focus in quarter-wavelength lithography

US7620930B2 · kind B2 · utility

Assignee

• ASML Masktools B.V. · NL

Inventors

• Douglas Van Den Broeke · Sunnyvale, US
• Jang Fung Chen · Cupertino, US

Key dates

• Filing date: Aug 22, 2005
• Grant date: Nov 17, 2009
• Expiry date: Apr 6, 2027

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F1/36
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method of generating a mask is provided that optimizes the placement and shape of optical proximity correction (OPC) features such as scattering bars. According to some aspects, the method includes model-based techniques for determining where to place assist features within the design, thereby eliminating the need for experienced mask designers to perform OPC, and also substantially reducing the time required to determine an acceptable OPC solution. According to further aspects, the method provides an OPC assist feature placement technique that enhances the resulting depth of focus even when imaging features have dimensions on the order of a quarter of the wavelength of the imaging system.