Nanopattern sidewall analysis

https://doi.org/10.1016/j.tsf.2018.11.009

 

There is a growing demand for the miniaturization and large-scale integration of semiconductor devices. In order to meet the requirements of the semiconductor industry, plasma etching processes using fluorocarbon-based gases have been developed to achieve vertically etched profiles for the formation of contact holes with high aspect ratios (HARs). In HAR contact etching, the slope of the etched SiO2 contact hole patterns can be controlled by nonvolatile passivation layers on the pattern sidewalls. These sidewall passivation layers play a very important role in obtaining lateral etching prevention, etching anisotropy, and vertical profiles. Therefore, the investigation of the chemical characteristics of sidewall residues is indispensable to create HAR contacts and to precisely control the anisotropy of nanopatterns. However, the existing surface analysis techniques such as EDS and AES provide only limited information on the pattern sidewall. In this study, we developed a novel method to examine the surface chemical composition of the residue formed on the sidewalls of nanoscale hole array patterns.