Improving Scanner Productivity and Control through Innovative Connectivity Application

摘要

Overlay accuracy is a key issue in semiconductor manufacturing process. In the ITRS roadmap also, overlay budgets are being reduced at a rapid pace. Coupled with the decreasing technology node budget allowances, alternative processing techniques are also driving overlay budgets to shrink. To meet those requirements, high order modeling of overlay error is potentially an effective solution. One source of overlay error is distortion matching between exposure tools. Matching can be broken down in to 2 areas; grid (stage related) and distortion (lens related). By using high order modeling of grid and distortion matching, we have been able to show overlay improvement of up to 50%. KLA-Tencor and Nikon are planning to provide automatic feedback system of high order compensation to exposure tool directly from metrology results. This feedback system can provide adjustment of coefficients of grid and distortion for periodical maintenance. Automating this process will lead to not only improved overlay control but also improved exposure tool productivity.