Condition optimization, reliability evaluation of SiO2-SiO2 HF bonding and its application for UV detection micro flow cell

H. Nakanishi, T. Nishimoto, M. Kanai, T. Saitoh, R. Nakamura, T. Yoshida, S. Shoji

Research output: Contribution to journalConference articlepeer-review

38 Citations (Scopus)


In order to apply SiO2-SiO2 bonding with hydrofluoric acid (HF bonding) for micro-electro-mechanical systems (MEMS) fabrication, the optimal bonding conditions were examined under different temperature, HF concentration and bonding time. The necessary HF concentration and the necessary time for bonding are reduced by elevating the bonding temperature. The time for bonding was reduced from 24 h at room temperature to 30 min at 80 °C, 60 min at 60 °C under the conditions of 0.5 wt.% HF concentration and 1.3 MPa applied pressure. The bonding time is comparable to that of anodic bonding. Reliability of the HF bonding was confirmed by the results of temperature cyclic tests and thermal shock tests. A long term stability of the bonded sample was also evaluated by helium (He) leak detection. The measured He leak rate was less than 2.0×10-9 atm cm3/s which is much smaller than that calculated value through component materials of the sample. A novel quartz UV detection micro flow cell for chemical analysis having Si shade structure was fabricated by the HF bonding. The absorbance unit for UV absorption detection of the cell was improved remarkably.

Original languageEnglish
Pages (from-to)136-141
Number of pages6
JournalSensors and Actuators, A: Physical
Issue number1
Publication statusPublished - 2000 May 22
EventThe 10th International Conference on Solid-State Sensors and Actuators TRANSDUCERS '99 - Sendai, Jpn
Duration: 1999 Jun 71999 Jun 10

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering


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