Master oscillator—power amplifier drive laser with pre-pulse for EUV light source

摘要

A device is described herein which may comprise an optical amplifier having a gain band including wavelengths λ1 and λ2, with λ1≠λ2; a pre-pulse seed laser having a tuning module for tuning a pre-pulse output to wavelength λ1; a main pulse seed laser generating a laser output having wavelength, λ2; and a beam combiner for directing the pre-pulse output and the main pulse output on a common path through the optical amplifier.

主权项

1. A method for generating EUV light by irradiating targets using at least a main pulse seed laser and a pre-pulse seed laser, comprising:
determining main pulse wavelength at said targets; determining desired pre-pulse energy at said targets; iteratively testing different output wavelengths for said pre-pulse seed laser until a satisfactory output wavelength for said pre-pulse seed laser is obtained, wherein said testing involves at least one of assessing resultant pre-pulse seed energy, assessing a ratio of said pre-pulse seed energy to main pulse seed energy, and assessing chromatic-aberration related focal spot spacing, and wherein said main pulse wavelength is different from said satisfactory output wavelength for said pre-pulse seed laser; and employing said satisfactory output wavelength for said pre-pulse seed laser to generate said EUV light.