| AVS 58th Annual International Symposium and Exhibition | |
| Plasma Science and Technology Division | Thursday Sessions |
| Session PS+SS-ThA |
| Session: | Plasma Surface Interactions (Fundamentals & Applications) II |
| Presenter: | Kenji Ishikawa, Nagoya University, Japan |
| Authors: | K. Ishikawa, Nagoya University, Japan N. Sumi, Nagoya University, Japan A. Kono, Kanazawa Institute of Technology, Japan H. Horibe, Kanazawa Institute of Technology, Japan K. Takeda, Nagoya University, Japan H. Kondo, Nagoya University, Japan M. Sekine, Nagoya University, Japan M. Hori, Nagoya University, Japan |
| Correspondent: | Click to Email |
A comprehensive understanding of interaction between plasmas and soft-materials is essential for advanced plasma processing technology. Simultaneous measurements of the gas-phase ESR signals and the surface dangling bond signal [1,2], and kinetics analysis of radical formation were performed using in situ real-time electron spin resonance (ESR). Chemical reactions under plasma are very complicated, due to the simultaneous irradiation of electrons, ions, radicals, and photons. Therefore, the individual contributions of each of these reactive species in the plasma must be elucidated.
An ESR system was connected to a plasma discharge system (2.45 GHz, 50 W) using a quartz tube with an inner diameter of approximately 9 mm. Gas (H2, O2, etc.) was flowed into the quartz tube and the pressure was maintained at approximately 10 Pa in the down-flow region. ESR measurements were conducted using a standard X-band (9 GHz) spectrometer (Bruker Biospin, EMX plus) with a microwave resonator. The quartz tube and polymer (PTFE, PMMA, etc.) film sample were inserted inside the ESR cavity in the down-flow region, typically 20 cm from the plasma discharge.
Individual contributions from gaseous radicals and plasma emission light have been studied in a similar manner using pallets for plasma process evaluation (PAPE) [3].
For irradiation with both atomic H and VUV on the PTFE film, significant acceleration in the rate of C-DB formation was observed at the beginning of irradiation.
Moreover, the surface radicals produced immediately changed to peroxy-radicals when the treated PTFE films were exposed to air. This suggests high reactivity of C-DB with oxygen and the peroxy-radical species can contribute to enhancement of the surface biocompatibility.
In summary, during exposure of gaseous radicals on the polymer surface, the in situ real-time ESR technique was demonstrated as a new experimental approach to the microscopic understanding of chemical reactions on surfaces with gaseous radicals during plasma processes. We have successfully obtained information regarding the reaction mechanism with radicals generated by plasma induced surface interactions.
ACKNOWLEDGMENT
This work was supported in part by the Knowledge Cluster Initiative (Second Stage) of the Tokai Region Nanotechnology Manufacturing Cluster.
REFERENCES
[1] S. Yamasaki, et al., Appl. Phys. Lett. 70, 1137-1139 (1997).
[2] K. Ishikawa, et al., Appl. Phys. Lett. 81, 1773-1175 (2002).
[3] S. Uchida, et al., J. Appl. Phys. 103, 073303:1-5 (2008).