2007 Volume 20 Issue 3 Pages 319-332
It has been a little more than a quarter century since chemical amplification resists were invented. They achieve a high sensitivity through a catalytic action of a photochemically generated acid. This drastically novel imaging concept was considered laboratory curiosity initially. However, the very first chemically amplified tBOC resist was quickly implemented in mass production of 1 megabit dynamic random access memory devices by deep UV lithography at IBM. Since then the chemical amplification concept has become the paradigm of advanced resist systems, enabling the industry to shift to shorter wavelengths (from 365 to 248, and then to 193 nm) for higher resolution and to follow the Moore's law. The chemical amplification resist invented for 1 μm resolution can now resolve 30 nm equal line/space patterns and continues to play a pivotal role in microlithography in the foreseeable future. This paper describes the inception and advancement of chemical amplification resists.
