Lithography mask having sub-resolution phased assist features

US9046761B2 · kind B2 · utility

Assignee

• Intel Corporation · US

Inventors

• Shem Ogadhoh · Beaverton, US
• Charles H. Wallace · Portland, US
• Ryan Pearman · San Jose, US
• Sven Henrichs · Hillsboro, US
• Arvind Sundaramurthy · Menlo Park, US
• Swaminathan Sivakumar · Portland, US

Key dates

• Filing date: Mar 18, 2013
• Grant date: Jun 2, 2015
• Expiry date: Jul 17, 2033

Classification

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

Abstract

Techniques are disclosed for using sub-resolution phased assist features (SPAF) in a lithography mask to improve through process pattern fidelity and/or mitigate inverted aerial image problems. The technique also may be used to improve image contrast in non-inverted weak image sites. The use of SPAF in accordance with some such embodiments requires no adjustment to existing design rules, although adjustments can be made to enable compliance with mask inspection constraints. The use of SPAF also does not require changing existing fab or manufacturing processes, especially if such processes already comprehend phased shift mask capabilities. The SPAFs can be used to enhance aerial image contrast, without the SPAFs themselves printing. In addition, the SPAF phase etch depth can be optimized so as to make adjustments to a given predicted printed feature critical dimension.