Method to repair localized amplitude defects in a EUV lithography mask blank

US6967168B2 · kind B2 · utility

Assignee

• EUV LLC. · US

Inventors

• Daniel G. Stearns · Los Altos, US
• Donald W. Sweeney · San Ramon, US
• Paul B. Mirkarimi · Sunol, US
• Henry N. Chapman · Hamburg, DE

Key dates

• Filing date: Jun 29, 2001
• Grant date: Nov 22, 2005
• Expiry date: Mar 23, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F1/74
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method and apparatus are provided for the repair of an amplitude defect in a multilayer coating. A significant number of layers underneath the amplitude defect are undamaged. The repair technique restores the local reflectivity of the coating by physically removing the defect and leaving a wide, shallow crater that exposes the underlying intact layers. The particle, pit or scratch is first removed the remaining damaged region is etched away without disturbing the intact underlying layers.