Prototype Development of an Optical Element Curvature Manipulator with Controlled Piezoelectric Actuator

摘要

Photolithography is the limiting step in realizing smaller feature size of Integrated Circuits (IC). For the 3x node, ArF immersion lithography systems with tighter focus budgets are required [1]. Wafer flatness is a main budget contributor [2], which can be reduced by ASML's TWINSCAN™ focus strategy with included curvature correction. A piezoelectric actuation system has been developed for this purpose that controls the curvature of an optical element in the lithography system [4], This paper presents the prototype developments.