Study on contact distortion during high aspect ratio contact SiO2 etching PROJECT TITLE :Study on contact distortion during high aspect ratio contact SiO2 etchingABSTRACT:As pattern density is increased in semiconductor integrated circuits (ICs) and pattern sizes are decreased to nanometer scale, high aspect ratio contact etching has become one of the most difficult processes in nanoscale IC fabrication. The increase in aspect ratio of the contact oxide etching raises problems such as low mask selectivity, microloading, pattern degradation, and etch stops. In this study, the authors investigated the effect of various oxide etch conditions such as mask materials, mask thickness, and oxide etch processes, on contact profile degradation. The results showed that greater contact pattern distortion occurred as the aspect ratio of the etched oxide was increased. The use of amorphous carbon instead of amorphous silicon as the etch mask, and the use of a more carbon-rich gas composition, lessened pattern distortion. The polymer deposited at the interface between the mask layer and the oxide layer appeared to significantly affect the degree of contact pattern distortion. By adding an in-situ polymer removal step during the overetch of a multistep contact oxide etch process with a 20:1 aspect ratio, about a 7% improvement in pattern distortion could be obtained without changing other conditions. Did you like this research project? To get this research project Guidelines, Training and Code... Click Here facebook twitter google+ linkedin stumble pinterest Residual stress modeling of density modulated silicon thin films using finite element analysis Application of electron stimulated desorption techniques to measure the isotherm and the mean residence time of hydrogen physisorbed on a metal surface