Finite element method analysis of evaluation of surface micro cracks using laser ultrasound generated by phase velocity scanning method

Harumichi Sato, Hisato Ogiso, Kazushi Yamanaka

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Nondestructive evaluation of defects that reduce material strength is critical to maintain the reliability of micro electro mechanical system (MEMS) components. We developed a new laser ultrasonic method, the phase velocity scanning (PVS) method, for this purpose. In a feasibility study, 200-μm-long micro standard defects (slits) on a Si wafer were fabricated with various depths (6.8 to 28.7 μm) and widths (2 to 5 μm), and scattered waves from a 6.8-μm-deep slit were successfully detected using 60 MHz surface acoustic waves. To analyze the directivity of acoustic waves generated by the PVS method and scattered waves from the slits, we developed 2D and 3D finite element method (FEM) programs. Using these programs, we confirmed that scattered waves are generated from a slit of 200 μm length, 10 μm depth, and 5 μm width. A comparison with the simulation of a conventional laser ultrasonic method showed that the PVS method has better directivity to suppress disturbing echoes generated in small objects.

Original languageEnglish
Pages (from-to)3184-3188
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume42
Issue number5 B
Publication statusPublished - 2003 May 1

Keywords

  • FEM
  • Laser ultrasonics
  • MEMS
  • NDE
  • Phase velocity scanning method

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Finite element method analysis of evaluation of surface micro cracks using laser ultrasound generated by phase velocity scanning method'. Together they form a unique fingerprint.

Cite this