Extendibility Evaluation of Industrial EUV Source Technologies for kW Average Power and 6.x nm Wavelength Operation

Akira Endo

doi:10.4236/jmp.2014.55039

Abstract

Interests in the extendibility are growing after the introduction of the LPP (Laser Produced Plasma) EUV source technology in the semiconductor industry, towards higher average power and shorter wavelength, based on the basic architecture of the established LPP EUV source technology. It is discussed in this article that the power scaling of the 13.5nm wavelength source is essentially possible by a slight increase of the driving laser power, CE (Conversion Efficiency) and EUV collection efficiency by some introduction of novel component technologies. Extension of the EUV wavelength towards BEUV (Beyond EUV), namely 6.x nm is discussed based on the general rule of the UTA (Unresolved Transition Arrays) of high Z ions, and development of multilayer mirrors in this particular wavelength region. Technical difficulties are evaluated for the extension of the LPP source technology by considering the narrower mirror bandwidth and higher melting temperature of the candidate plasma materials. Alternative approach based on the superconducting FEL is evaluated in comparison with the LPP source technology for the future solution.

Highlights

The semiconductor industry is pursuing continuous shrinking of the micro circuit for the generation business
After the ArF immersion lithography, extreme ultraviolet (EUV; 13.5 nm, 92.5 eV) radiation is in the introduction phase as an exposure tool for the mass production at or below the 22 nm technology node
The basic architecture of the LPP EUV source was recently established after one decade of intensive research and engineering, to present a platform to supply highly stable, clean in band EUV incoherent light peaked at 13.5 nm, to be integrated into a EUV scanner [2]

Summary

Introduction

The semiconductor industry is pursuing continuous shrinking of the micro circuit for the generation business. (2014) Extendibility Evaluation of Industrial EUV Source Technologies for kW Average Power and 6.x nm Wavelength Operation. Generation source technology demonstrated approximately 160 W with 3% conversion efficiency [5] It is discussed in this article on the extendibility of the established plasma source technology towards kW average EUV power level. A typical configuration of the LPP EUV source for HVM (High Volume Manufacturing) application is explained, especially by indicating the efficiency of each component It is discussed on the physical reason of the selected component technologies, and is estimated on the physical limit of the improvement. Available EUV power is limited due to the narrower bandwidth of the multilayer mirrors in this wavelength region, in spite of the fact that the emission property is essentially the same among any atoms.

Basic Architecture of the LPP EUV Source and Extension to kW Average Power

Picosecond Pre-Pulsing of Droplets

Operation in Shorter Wavelength Region

Findings

Conclusion