Ion-beam-induced dual-tone imaging of polyimide via two step imidization

Suzuki, Yasuyuki; Maekawa, Yasunari; Yoshida, Masaru; Maeyama, Katsuya*; Yonezawa, Noriyuki*

Dual tone imaging of polyimide films was prepared by Xe ion beam irradiation of partially imidized polyamic acid (PAA) films followed by alkaline etching in aqueous tetramethylammonium hydroxide solution and heating of treated films. In 87% imidized PAA film, ion beam irradiation produced a negative hemispheric structured image with 1.0 mm height and 1.5 mm diameter. In contrast, a positive hole pattern with 0.3 mm diameter appeared on the 82% imidized PAA film. Positive and negative images were considered to be switched by slight change in the balance of scission and crosslinking of the polymer chains, resulting from energy deposition of the ion beam.