Proceedings Article | 30 March 2010
Proc. SPIE. 7639, Advances in Resist Materials and Processing Technology XXVII
KEYWORDS: Electron beam lithography, Optical lithography, Polymers, Glasses, Silicon, Photoresist materials, Microelectronics, Plasma etching, Fluorine, Photoresist developing
The chemical waste generated in today's microelectronic fabrication processes has driven the need to develop a more
environmentally benign process. Supercritical CO<sub>2</sub> (scCO<sub>2</sub>) has been evaluated as an environmentally friendly solvent for photoresist development. It is nontoxic, nonflammable, and inert under most conditions. It also possesses advantages
such as liquid-like densities, gas-like diffusivity, and zero surface tension. Although scCO<sub>2</sub> is a poor solvent for most
polymers, certain fluorine-and silicon-containing polymers have shown solubility in scCO<sub>2</sub>. Previously, negative-tone
patterns of 100nm have also been developed in scCO<sub>2</sub> using conventional photoresists such as ESCAP and PBOCST
with the aid of fluorinated quaternary ammonium salts (QAS). However, the incorporation of fluorine degrades plasma
etch resistance, and because of their persistence in nature, fluorinated compounds are coming under increased scrutiny.
In order to make the process more environmentally benign, the elimination of fluorine is desirable. Some molecular glass
photoresists without the incorporation of fluorine and silicon have thus been designed and synthesized to be processed in
scCO<sub>2</sub>. In addition to scCO<sub>2</sub>, another environmentally friendly, low VOC solvent, decamethyltetrasiloxane has also been investigated to develop conventional photoresists. In this paper, we demonstrate the patterning of photoresists in both
scCO<sub>2</sub> and decamethyltetrasiloxane.
