Synchronous Schlieren image analysis of megasonic single wafer cleaning

Takashi Azuma, Akihiro Tomozawa, Hideo Kinoshita, Shin Ichiro Umemura

Research output: Contribution to journalConference articlepeer-review


A synchronous Schlieren system for quantitative analysis of the ultrasonic field in megasonic wafer cleaning is described. We found that LSI patterns on the side of a silicon wafer opposite to the incidence of ultrasound were damaged during single-wafer cleaning. Defects were observed when ultrasound penetrated through the wafer at a certain angle of incidence. A Schlieren system with pulsed illumination synchronized to the ultrasonic phase was constructed, and the wave fronts in water around the wafer during megasonic cleaning were imaged. We found that ultrasound passed through the wafer when Lamb waves were generated in the wafer. This was confirmed with a computer simulation of the wave propagation.

Original languageEnglish
Pages (from-to)55-58
Number of pages4
JournalDiffusion and Defect Data Pt.B: Solid State Phenomena
Publication statusPublished - 2000 Dec 1
Event5th Internatinal Symposium on Ultra Clean Processing of Silicon Surfaces (UCPSS 2000) - Ostend, Belgium
Duration: 2000 Sep 182000 Sep 20

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Science(all)
  • Condensed Matter Physics
  • Physics and Astronomy (miscellaneous)


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