METHOD OF FORMING THIN FILM PATTERN HAVING LARGE ASPECT RATIO OPENING IN RESIST STRUCTURE

摘要

A high aspect ratio structure (with a large height-to-linewidth ratio) is formed on a substrate by means of two resist layers with different kinds of radiation to which they are sensitive, respectively, with an actinic radiation sensitive resist below and an electron sensitive resist above. In addition, a metallic film is shaped by means of exposure of the upper layer of resist to form a metallic mask through which the lower layer of resist is exposed. Exposure may be performed by a "subtractive" technique or an "additive" technique. In the case of the subtractive technique, the substrate is coated by a first actinic resist above which are deposited first a metallic film and then a top layer of electron resist. The top resist layer is exposed and developed and the metal layer is etched so the lower resist can be exposed and developed with the pattern formed in the metal, with the pattern shape originally exposed in the top layer of resist extending down to the substrate.