Dielectric characteristics of low-permittivity silicate using electron beam direct patterning for intermetal dielectric applications

Abstract

A direct patterning technology of low-permittivity silicate-based polymer is investigated with electron-beam lithography for multilevel interconnections. The smallest feature size of 60 nm for damascene lines can be directly patterned in the silicate film. In this direct patterning, dielectric regions exposed by electron beam are crosslinked and form desirable patterns, while the others are dissolvable in an aqueous solution containing 2.38% tetramethylammonium hydroxide. With an optimum condition of electron-beam lithography, the electron-beam-irradiated silicate exhibits superior dielectric properties than that of the furnace-cured silicate film, due to minimizing the break of Si-H bonds and moisture uptake. The explanation is in agreement with the analyses of Fourier transform infrared spectroscopy and thermal desorption spectroscopy. (C) 2003 American Institute of Physics.