Abstract

A laser produced extreme ultraviolet (EUV) source based on a water droplet target has been implemented an auxiliary electrode system between the source and the first collector mirror. The auxiliary electrode system creates a repeller electric field, possibly a dc voltage imposed on the mirror that slows down and reverses the trajectories of ions from the source before they impact the collection mirror. The source modified according to the invention was evaluated with respect to the demands of EUV lithography and found to have much extended operational lifetimes. The spectral distribution of the generated radiation as well as the conversion efficiency into line radiation at 13 nm was determined. Long time measurements of the reflectivity of silicon/molybdenum multilayer mirrors for up to from 10.sup.7 to 10.sup.9 shots show the useful influence of the treatment of ions emitted from the source. Several methods of debris reduction were tested and discussed. Surface analysis of the treated

Document Type

Patent

Patent Number

US 6,377,651

Application Serial Number

09/685,291

Issue Date

4-23-2002

Current Assignee

UCFRF

Assignee at Issuance

UCFRF

College

College of Optics and Photonics

Department

CREOL

Allowance Date

12-18-2001

Filing Date

10-10-2000

Assignee at Filing

UCFRF

Filing Type

Nonprovisional Application Record

Donated

no

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