An in-situ temperature measurement system for DUV lithography

Abstract

The absolute temperature, as well as the spatial uniformity, of points on a silicon wafer during the various deep ultra-violet lithographic steps has a direct impact on the critical dimension. As more stringent temperature specifications must be satisfied in order to produce smaller silicon features, there is a need to continuously monitor the substrate temperature. This paper describes an algorithm for post-processing the output of an in-situ temperature measurement unit in order to lower its effective response time. Experimental results are then presented to demonstrate that the desired measurement accuracy during the transient part of the post-exposure bake process can be achieved.