Studies on low-temperature direct bonding of VUV, VUV/O3 and O2 plasma pretreated cyclo-olefin polymer

Hidetoshi Shinohara*, Jun Mizuno, Shuichi Shoji

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

69 Citations (Scopus)


Low-temperature direct bonding of two cyclo-olefin polymer (COP) plates is realized by pretreatments of vacuum ultraviolet (VUV) light irradiation, VUV irradiation in the presence of oxygen gas (VUV/O3), or oxygen plasma treatment. The bond strength was strong enough to observe bulk destruction on the fractured surfaces after the tensile test of the sample. To investigate the mechanism underlying the low-temperature direct bonding, attenuated total reflection Fourier-transform infrared spectrometer (ATR-FT-IR), X-ray photoelectron spectroscopy (XPS), contact angle measurements, and atomic force microscopy (AFM) surface analysis methods were carried out for the treated COP samples. These experimental results showed that polar functional groups (e.g., -OH, -COOH) are generated by each treatment. These groups are expected to generate dipolar interactions including hydrogen bonds on the surfaces of the pretreated COPs at room temperature. In case of VUV and VUV/O3 treatments, degradation of COP was also occurred and the degradation layer acted as an adhesive for the direct bonding. Thermal annealing enhances creation of strong covalent bonds (-C-O-C-) changed from hydrogen bonds.

Original languageEnglish
Pages (from-to)124-131
Number of pages8
JournalSensors and Actuators, A: Physical
Issue number1
Publication statusPublished - 2011 Jan


  • Cyclo-olefin polymer
  • Direct bonding
  • Oxygen plasma
  • Vacuum ultraviolet light

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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