Reduction of loading effects with the sufficient vertical profile for deep trench silicon etching by using decoupled plasma sources

This study presents the features of profile evolution in deep trench silicon etching, which is crucial for commercial wafer-processing applications. Experiments to minimize the macroscopic and microscopic loading effects were performed with anisotropic deep trench etching in high-density decoupled HBr/CF4/Cl2/O2 and SF6/CF4/O2 plasmas. The process parameters, including gas chemistry, pressure, source power, bias power, and dual electrostatic chuck system, were also optimized for these applications. Notching and trenching phenomena were effectively improved during the deep trench etching process. The optimized deep trench silicon process resulted in vertical profiles (87–90°) with a loading effect of <1% by using the SF6-based chemistry, which was more effective than the HBr-based process. The bias constant verified the linear-etching parameter system, depending on the pattern density of the device, in order to commercialize deep trench silicon etching for mass production.