Atmospheric linear-type mixed-gas plasma source with low-particle emission for large area surface treatment
Junnosuke Furuya, Koki Hihara, Kai Fukuchi, Taiki Osawa, Akane Yaida, Akitoshi Okino*
* The author to whom correspondence should be addressed.
Laboratory for Future Interdisciplinary Research of Science and Technology, Institute of Science Tokyo, Yokohama, Japan
Abstract
In recent years, atmospheric low-temperature plasma has been extensively utilized for surface treatments. In our laboratory, an atmospheric multi-gas plasma jet source capable of generating low-temperature plasma with various gas species was developed. However, due to the 1 mm diameter of the plasma injection hole in this device, two-dimensional scanning was required to treat large areas. To address this limitation and enable large-area treatment with onedimensional scanning, this study developed an atmospheric linear-type mixed-gas plasma source. This plasma source features a plasma irradiation slit measuring 1 mm × 349 mm, emitting low-temperature plasma in a gas curtain-like manner. Atmospheric low-temperature plasma was generated using various gases by applying a radio frequency (RF) of 13.56 MHz to the electrodes. The performance of this plasma source was evaluated by measuring water contact angles and the particles emitted. Results indicated an enhanced hydrophilic effect when molecular gases were mixed with argon. Specifically, the contact angle decreased by 42 degrees when nitrogen was mixed with argon, compared to a reduction of 30 degrees with pure argon. Additionally, the uniformity of hydrophilic effect of argon plasma mixed with molecular gases improved with higher RF power. For example, when plasma treatment was performed with 2.0% nitrogen mixed into argon, the dispersion across eight measurement points was 3.62 at 500 W RF power, compared to 35.1 at 200 W. Furthermore, particle emission measurements revealed that the particles from this plasma source complied with the class 100 cleanroom standards commonly used in semiconductor manufacturing. These findings suggest that the linear-type mixed-gas plasma source is suitable for applications in semiconductor manufacturing and other industries that require cleanroom environments.
Keywords - Atmospheric plasma, low-temperature plasma, surface treatment, hydrophilization, particle contamination.