A feature scale model for trench capacitor etch rate and profile

To support the optimization of aspect ratio and profile of DRAM trench capacitors we have developed two feature scale models of different complexity. A compact model calculates the etch rate for a given trench geometry by solving an integral equation for the neutral and ion transport inside the trench. This approach yields a quantitative prediction of the variation in etch rate for different trench profiles. An additional high level model calculates both the etch rate and the trench profile as a function of process parameters. This is achieved by using a level set front propagation, Monte Carlo particle transport, and chemical reaction rates. The results of both models are in good agreement with each other as well as with experimental data for several technology nodes. With our high level model it is now possible for the first time to simulate the feature evolution during deep trench etching of advanced DRAM generations.