イオン照射PVDF膜のエッチング速度への熱処理効果

Heat-treatment effect on etching rate of ion-irradiated poly(vinylidene fluoride) thin films

越川 博; 八巻 徹也; Rohani, R.*; 高橋 周一*; 長谷川 伸; 浅野 雅春; 前川 康成

Koshikawa, Hiroshi; Yamaki, Tetsuya; Rohani, R.*; Takahashi, Shuichi*; Hasegawa, Shin; Asano, Masaharu; Maekawa, Yasunari

ポリフッ化ビニリデン(PVDF)膜のイオン穿孔作製時、エッチングの前に加熱処理することで高感度化を検討した。Xeイオン照射後、30日間大気中120Cで加熱した。比較として25, -84Cも同様に処理し、80Cの9M KOH水溶液でエッチングしてイオン穿孔膜を得た。エッチング時の電導率測定から算出した潜在飛跡エッチング速度は120Cで6.6m/hで-84Cの6倍、25Cの4倍高い値となり、熱処理による高感度化が明らかになった。

Poly(vinylidene fluoride) thin films irradiated with four kinds of ion beams were exposed to a 9 M KOH aqueous solution after their storage in air for 30 or 90 days at different temperatures. According to the conductometry, the heating at 120C was found to enhance the etch rate in the latent track without changing that in the bulk, thereby enabling us to obtain very high etching sensitivity for the preparation of nano-sized through-pores. The formation of hydroperoxides during this pretreatment should facilitate the introduction of the etching agent to improve etchability. Additionally, the irradiation of higher-LET ions, causing each track to more activated sites (like radicals), was preferable to achieve high sensitivity of the etching.