High power fiber laser driver for efficient EUV lithography source with tin-doped water droplet targets

Kai-Chung Hou,Kazutoshi Takenoshita,Aghapi G Mordovanakis,Martin Richardson,John Nees,Simi George,Almantas Galvanauskas,Bruno Lafontaine

doi:10.1364/oe.16.000965

Abstract

In this paper we report the development of nanosecond-pulsed fiber laser technology for the next generation EUV lithography sources. The demonstrated fiber laser system incorporates large core fibers and arbitrary optical waveform generation, which enables achieving optimum intensities and other critical beam characteristics on a laser-plasma target. Experiment demonstrates efficient EUV generation with conversion efficiency of up to 2.07% for in-band 13.5-nm radiation using mass-limited Sn-doped droplet targets. This result opens a new technological path towards fiber laser based high power EUV sources for high-throughput lithography steppers.

Highlights

Demands for light sources in the extreme ultraviolet (EUV) and soft-X-ray region have been growing in recent years due to potential applications on element-specific spectroscopy, highresolution microscopy, and surface analysis [1]
In this paper we report the development of nanosecond-pulsed fiber laser technology for the generation EUV lithography sources
Experiment demonstrates efficient EUV generation with conversion efficiency of up to 2.07% for in-band 13.5-nm radiation using mass-limited Sn-doped droplet targets

Summary

Introduction

Demands for light sources in the extreme ultraviolet (EUV) and soft-X-ray region have been growing in recent years due to potential applications on element-specific spectroscopy, highresolution microscopy, and surface analysis [1]. The search for a high power light source at shorter wavelengths for generation lithography steppers has been the main driving force for the rapid development of a EUV light source in recent years. The two leading candidates for EUV production are laser-produced plasma (LPP) and discharge produced plasma (DPP). LPP EUV have potential advantages over DPP EUV in terms of debris mitigation, source brightness, and capability of high repetition rate power scaling [4]. Recent development of kW class high average power lasers has closed the power gap between LPP and DPP [5]

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