Lithographic scanner stability improvements through advanced metrology and control

Holistic lithography is needed to cope with decreasing process windows and is built on three pillars: Scanner Tuning, Computational Lithography and Metrology & Control. The relative importance of stability to the overall manufacturing process latitude increases. Overlay and focus stability control applications are important elements in improving stability of the lithographic process. The control applications rely on advanced control algorithms and fast and precise metrology. To address the metrology needs at the 32 nm node and beyond, an optical scatterometry tool was developed capable of measuring CD, focus-dose as well as overlay. Besides stability and control of lithographic performance also scanner matching is a critical enabler where application development and metrology performance are key. In this paper we discuss the design and performance of the metrology tool, the focus and overlay control application and the application of scatterometry in scanner matching solutions.