3-DIMENSIONAL SILOXANE RESIST FOR THE FORMATION OF NANOPATTERNS WITH MINIMUM LINEWIDTH FLUCTUATIONS

Linewidth fluctuation of resist patterns is a serious problem in fabri cating nanodevices when lithographic resolution is improved to the nan ometer scale. As a resist material for reducing linewidth fluctuations , we evaluate hydrogen silsesquioxane (HSQ) with a three-dimensional f ramework from the standpoints of resist patterning and its ability to reduce linewidth fluctuation. Infrared analyses indicate that SiH bond s in HSQ are broken by electron-beam irradiation, and consequently, th e crosslinking required for negative tone patterning is generated. By applying a TMAH developer suitable for the dissolution of the siloxane bonds in HSQ, we improve contrast and reduce the thickness loss of th e lightly exposed resist area. In addition, the HSQ resist has relativ ely high sensitivity for resist materials without any reactive groups. The etching durability sacrificed for the attainment of high sensitiv ity is improved by oxygen plasma treatment. No damage, such as pattern -shape deformation after the oxygen plasma treatment, is observed. Lin ewidth fluctuation due to edge roughness of resist patterns results fr om aggregates in the resist polymer. Aggregates in HSQ are small owing to its three-dimensional framework. In addition, the excellent develo pment properly of HSQ avoids any influence from polymer aggregates on development. Consequently, linewidth fluctuation can be reduced to les s than 2 nm. This leads to a decrease in the variation of gate capacit ance in single-electron transistors. (C) 1998 American Vacuum Society.