Lithographic evaluation of a positive-acting chemically amplified resist system under conventional and projection electron-beam exposures

Abstract

New resist materials and processes are necessary to pattern sub-0.18 μm design rule circuits with advanced x-ray and electron-beam lithographic technologies. We have evaluated a new deep-ultraviolet multicomponent positive-acting chemically amplified resist (ARCH: advanced resist chemically amplified), that exhibits excellent resolution under deep-ultraviolet exposure, and furthermore an overcoat is not used to protect against any basic airborne contaminants. Different formulations of the resist system were studied with electron-beam lithography in an attempt to enhance sensitivity and maintain wide process latitude and high resolution. In our study we compare the lithographic characteristics of the resist under electron-beam exposure, with either a Cambridge EBMF vector scan system operating at 40 keV or a JEOL JBX-5DII system operating at 50 keV, to those obtained at 100 keV with a scattering with angular limitation projection electron lithography (SCALPEL) experimental tool. Using the direct write exposure tool at 50 keV, the basic resist formulation displayed a 0.09 μm resolution and a sensitivity of 25 μC/cm2. When an enhanced resist system was studied, a sensitivity of 9 μC/cm2 was displayed with comparable resolution. The resolution of the positive-acting resist material exposed with SCALPEL was not only affected by the writing tool, but also by the mask tone.