Introduction

A system to predict etching profiles was developed by combining the results obtained from on-wafer sensors and those obtained from computer simulations. We developed on-wafer UV, on-wafer charge-up, and on-wafer sheath shaped sensors. These sensors could measure plasma process conditions, such as UV irradiation, charge-up voltage in high aspect ratio structures, and ion sheath conditions at the plasma/surface interface on the sample stage. Then, the output of the sensors could be used for computer simulations. The system could predict anomalies in etching profiles around large scale 3D structures that distorted the ion sheath and its trajectory. It could also predict anomalies in etching profiles caused by charge accumulation in high-aspect ratio holes. Moreover, it could predict the distribution of UV-radiation damage in materials.