PATTERNING OF POLY(3-ALKYLTHIOPHENE) THIN-FILMS BY DIRECT-WRITE ULTRAVIOLET-LASER LITHOGRAPHY

Thin films of poly(3-methylthiophene) (P3MT), poly(3-butylthiophene) ( P3BT) and poly(3-hexylthiophene) (P3HT) have been patterned into micro structures using the 325 nm radiation from a helium-cadmium laser. At sufficiently high energy fluences, spontaneous mass removal occurred i n all three polymers to give groove structures about 3 mu m wide. At l ower incident fluences, both P3BT and P3HT underwent crosslinking as a result of I:he irradiation. Using chloroform as a developer, 1-6 mu m wide line structures were obtained on glass substrates. For the lowes t fluences, the P3BT linewidths after development were narrower than t he nominal beam diameter. The present results are potentially useful t o the fabrication of polymer electronic devices and microlithography. (C) 1998 Elsevier Science S.A. All rights reserved.