Critical dimension and real-time temperature control for warped wafers

In this paper, we present the experimental results on critical dimension (CD) control via real-time temperature control for warped wafers. As opposed to run-to-run control where information from the previous wafer or batch is used for control of the current wafer or batch, the approach here is real-time and make use of current information for control of the current wafer CD. In this paper we demonstrate that real-time control of the post-exposure bake temperature to give nonuniform temperature distribution across the warped wafer can reduce CD nonuniformity across the wafer.