Evaluation and selection of EUVL-grade TiO2-SiO2 ultra-low-expansion glasses using the line-focus-beam ultrasonic material characterization system

Mototaka Arakawa, Yuji Ohashi, Jun Ichi Kushibiki

Research output: Contribution to journalConference article

5 Citations (Scopus)

Abstract

We proposed a new coefficient-of-thermal-expansion (CTE) evaluation method for ultra-low expansion glasses using the line-focus-beam ultrasonic material characterization system. In this paper, we investigated evaluation procedures for photomasks and optical mirrors with practical size used as reflective optics in extreme ultraviolet lithography (EUVL) systems. Two specimens were prepared with their surfaces parallel to the striae plane from commercial TiO 2-SiO2 ultra-low-expansion glass ingots. Homogeneities/inhomogeneities of specimens were evaluated at 225 MHz. Evaluation procedures with sufficient accuracy were established for analysis of striae parameters such as striae periodicity and variations. Our ultrasonic method should be standardized as a new evaluation method not only for development of the EUVL-grade glass and evaluation of the production processes, but also for quality control and selection of the production lots.

Original languageEnglish
Article number651725
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume6517
Issue numberPART 2
DOIs
Publication statusPublished - 2007 Oct 15
EventEmerging Lithographic Technologies XI - San Jose, CA, United States
Duration: 2007 Feb 272007 Mar 1

Keywords

  • CTE evaluation
  • EUVL system
  • Leaky surface acoustic waves
  • Line-focus-beam ultrasonic material characterization system
  • Quality control
  • Selection
  • TiO-SiO ultra-low-expansion glass
  • Velocity measurement

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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