Coherent EUV Light Sources Based on High-Order Harmonic Generation: Principles and Applications in Nanotechnology

Kapteyn, Henry C., JILA; Murnane, Margaret M., JILA; Esashi, Yuka, Univ. of Colorado Boulder; Tanksalvala, Michael, JILA; Knobloch, Joshua L., JILA; Liao, Chen-Ting, JILA; Hickstein, Daniel, Octave Photonics LLC; Bargsten, Clayton, KMLabs, Inc.; Dorney, Kevin, imec; Petersen, John S., imec

doi:10.1117/3.2638242.ch21

Book: Photon Sources for Lithography and Metrology

Editor(s): Vivek Bakshi

Chapter Author(s): Henry Kapteyn, Margaret Murnane, Yuka Esashi, Michael Tanksalvala, Joshua Knobloch, Chen-Ting Liao, Daniel Hickstein, Clayton Bargsten, Kevin Dorney, John Petersen

Published: 2023

https://doi.org/10.1117/3.2638242.ch21

Author Affiliations +

Abstract

Although the EUV lithography process makes good use of incoherent EUV illumination, many other applications—particularly in the area of metrology for nanotechnology, can either benefit from, or can only be done with, coherent light. In recent decades, a number of technologies have been developed to implement EUV sources that exhibit high spatial coherence: EUV lasers using highly ionized plasmas as the laser medium, short-wavelength free-electron lasers, and high-order harmonic generation (HHG). Of these technologies, HHG technology is both the smallest in scale and easiest to implement, and also exhibits the highest degree of coherence and control over the source characteristics. Furthermore, work in the past decade has proven the potential of these sources for nanotechnology applications in a variety of demonstration experiments. Thus, coherent HHG sources are poised to become an increasingly useful and valuable light source for metrology and imaging applications, in contrast to the high-power Sn plasma sources used for lithographic exposure.