Scan Speed Optimization for Wafer Exposure Time Reduction in Semiconductor Manufacturing

The step and scan method used in wafer photolithography has a disadvantage of taking a long time despite its high resolution. There are several factors that can influence the time, such as the stage performance, light intensity, scan speed, and other variables. The scan speed may be changed within a range where the equipment can meet the process dose requirement. Thus, it is necessary to determine the optimal scan speed within the range that minimizes the process time. In this paper, we formulate the optimization problem to solve this issue and provide an analytical form of the wafer exposure time using a simple acceleration-based step motion model. An example demonstrates that a scan speed solution can be found, as well as provides a performance comparison with other scan speed candidates in terms of reducing the wafer exposure time.