Dry development in an O2/SO2 plasma for sub-0.18 μm top layer imaging processes

Dry development using thin layer imaging (TLI) in either a bilayer approach or top surface imaging are currently investigated as viable alternatives to extend optical lithography to 0.13 μm and below. This article describes a systematic study of dry development in a LAM TCP9400SE inductively coupled plasma etcher for both a single layer TLI resist process and for a bilayer resist process using O2 and SO2/O2 chemistries. The effect of the important machine parameters such as TCP power, bias power, O2 and SO2 gas flows, on the process characteristics (etch rate, selectivity, uniformity, anisotropy) and on the lithographic performance (resolution, profile control, proximity) of a TSI process at 248 has been investigated by means of statistically designed experiments. As line edge roughness (LER) is a critical issue for TSI, the effect of the dry development conditions on LER have been quantified. The effect of temperature on profile control is also presented. In a second part of this article, these trends ha...