Reduction and control of intrafield focus variation on 7nm technology

With each technology node, overall focus budgets have become increasingly tighter in order to meet the necessary product requirements. The 7nm node has required us to define new opportunities for addressing top contributors to the focus budget. Field curvature in particular has been identified as a key contributor to the intrafield focus budget, contributing around 50%. This paper will introduce two new methodologies for improving field curvature; one a hardware solution and one a software solution.