Imaging budgets for EUV optics: Ready for 22nm node and beyond

摘要

We derive an imaging budget from the performance of EUV optics with NA = 0.32, and demonstrate that the 22nm node requirements are met. Based on aerial image simulations, we analyze the impact of all relevant contributors, ranging from conventional quantities, like straylight or aberrations, to EUV-specific topics, namely influence of 3D mask effects and facetted illumination pupils. As test structures we consider dense to isolated lines, contact holes, and 2D elbows. We classify the contributions in a hierarchical order according to their weight in the CDU budget and identify the main drivers. The underlying physical mechanisms causing different contributions to be critical or less significant are clarified. Finally, we give an outlook for the 16nm and 11nm nodes. Future developments in optics manufacturing will keep the budgets controlled, thereby paving the way to enable printing of these upcoming nodes.