Silicon-rich surfaces in polymer resists

Abstract

The drive toward submicron geometries in microelectronics will require high resolution image transfer processes. The use of oxygen reactive ion etching (O2 RIE) in the dry development of high resolution, high aspect ratio relief images, is the subject of current research on microelectronic materials. A variety of silicon-containing polymers have been developed for use in multilayer resists which combine radiation sensitivity with oxygen plasma-resistance. These materials require 8-12 weight percent silicon to achieve etch resistance, often compromising other desirable properties. We are investigating the behavior of microphase-separated, surface-active, block polymer films in oxygen plasma environments, to gain understanding of issues such as silicon concentration and the interfacial thickness necessary for etch resistance. Etch resistance at silicon levels far below that required in 'random' systems has been found in these micro-heterogeneous materials. Aspects of block polymer synthesis, morphological structure, surface characteristics, and RIE behavior are discussed.