Dry photochemical etching of Bi films

Abstract

Illumination of a light-sensitive polymer layer cast on top of a Bi film leads to etching in situ of the metallic film. The greater the exposure, the less the film thickness. The layer consists of a polymer binder, aromatic amines (Am)[namely diphenylbenzylamine (DPBA), diphenylamine (DPA) or dibenzylaniline (DBA)] and hexabromodimethylsulfone (HBMS), forming light-sensitive charge-transfer complexes Am-HBMS. Initial exposure to 365 and 436 nm light, followed by exposure to 650nm light results in amplification with a consequently high sensitivity for the photoetching process (ca. 3 × 10^–4 J cm^–2).