Spectroscopic ellipsometry and reflectometry: a user´s perspective

We discuss how analytical tools in a characterization lab can be used to enhance metrology tools in a fab. The emphasis is on the interaction between a characterization lab and a wafer fab belonging to the same industrial company. Specifically this work will deal with ex situ analysis rather than in situ metrology. A metrology tool in a fab must be clean, fast, simple to operate, and must be able to measure small features. A classical example is a reflectometry tool. On the other hand, a tool in a characterization lab can handle a much more complex sample, can take a significantly longer time for the analysis, and often has the luxury of using a blanket wafer. The analyst is also available for consulting with regard to optimum samples configuration in order to generate the information required. Our emphasis will be on using spectroscopic ellipsometry in a characterization lab to develop optical constants of unusual material so that this information can be used in a reflectometry tool in the fab.