Sub-100-nm pattern fabrication using LB resist and e-beam or synchrotron radiation excited plasma

Abstract

ABSTRACT For fine pattern fabrication using c-beam lithography, the resist film thickness must be decreased, and therefore, the plasmaetching process must be reformed. We have proposed the use of Electron Beam Excited Plasma (EBEP) and Synchrotron Radiation Excited Plasma (SREP) etching techniques for fine pattern etching. Our EBEP reactor uses a 1 m thick polyimide interface film, which isolates the reactor from the c-beam source but allows electron transmission at the same time. The transmission of high energy electrons through the interface film causes ablation of the interface film and deposition of carbonaceous film on the substrate in the reactor. From the study of this phenomenon in Ar atmosphere, it wasfound that the ablated species are charged with either polarity. However, a pronounced and non-uniform deposition was observed for a particular substrate holder, which caused non-uniform electric field near the substrate. Thus, with an improved substrate holder, silicon etching was realized in CF4 gas. This etching could be observed only under negative biascondition, as seen earlier for SREP etching. Sub 100 urn line and space patterns were successfully etched with SREP andEBEP etching techniques using ultra thin Langmuir Blodgett (LB) stearic acid resist.Keywords : Electron-Beam Lithography, Langmuir Blodgett Films, Silicon Etching, Electron Beam Excited Plasma,Interface Ablation, Synchrotron Radiation Excited Plasma