Impregnation of resist with functional molecules using supercritical fluid: a new approach to resist engineering for advanced lithography

This paper describes an innovative approach to lithography processes using a supercritical fluid. The key idea is to improve a resist by exploiting the special properties of supercritical fluid: it is a good solvent with good diffusivity. The results of this study show that various kinds of molecules can be dissolved in supercritical carbon dioxide, and distributed uniformly throughout a resist. For example, the etch rate of ArF resist is reduced when functional molecules with a high etching durability are added to it. The unique feature of this technique is that the resist can be modified after exposure and development without damaging resist patterns. This technique constitutes a revolutionary way of enhancing resists that could have a big impact on resist composition and processes.