Method of extreme ultraviolet lithography projection objective

US9323158B2 · kind B2 · utility

Assignee

• National Institute of Metrology · CN

Inventors

• Yanqiu Li · Beijing, CN
• Fei Liu · Wuxi, CN

Key dates

• Filing date: Feb 28, 2012
• Grant date: Apr 26, 2016
• Expiry date: Jul 30, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/705
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A design method of extreme ultraviolet lithography projection objective comprises: determining the optical design parameters of the lithography projection objective, setting the projection objective to include six lenses and an aperture diaphragm, and dividing the six lenses into the three groups according to the beam propagation direction; determining the radii and the intervals of the first and third groups, respectively; and determining the radii and the intervals of the second group of lenses according to the parameters of the foregoing two groups of lenses. The design method has the advantage of avoiding the blindness in revising and error testing of the existing structure of the conventional optical design method by calculating lens structures that meet the parameter conditions, so that light rays can be selected conveniently according to the special requirements of optical processing detection, and a mass of searches and judgments can be avoided.