Finite Element Model for Prediction of Back-End-of-Line Process Induced Wafer Bow for Patterned Wafer

With the increased technological advancement within the semiconductor industry, there has been a need for wafer level products that allow for higher electrical performance and increased power efficiency. This leads to more metal content in the back-end-of-line wafer fabrication process. During the wafer fabrication process a large amount of stress is generated in back-end-of-line which can lead to severe wafer bow. High wafer bow can cause fabrication issues. In order to understand and predict the wafer bow, finite element method based models were developed to support back-end-of-line process step definitions and setting design rules to limit the wafer bow. In the finite element method based model, the fully patterned back-end-of-line stack is replaced by effective orthotropic material properties generated at several die level models to capture the non-uniform metal density across the wafer. Finally, the current study shows that the newly developed finite element method models are in good agreement with experimental data.