Process Transfer Strategies between ASML Immersion Scanners

摘要

A top challenge for Photolithographers during a process transfer involving multiple-generation scanners is tool matching. In a more general sense, the task is to ensure that the wafer printing results in the receiving fab will match or even exceed those of the originating fab. In this paper we report on two strategies that we developed to perform a photo process transfer that is tailored to the scanner's capabilities. The first strategy presented describes a method to match the CD performance of the product features on the transferred scanner. A second strategy is then presented which considers also the down-stream process tools and seeks to optimize the process for yield. Results presented include: ASML TWINSCAN? XT: 1700i and XT:1900i scanners ID printing results from a line-space test reticle, parametric sensitivity calculations for the two scanners on ID patterns, simulation predictions for a process-optimized scanner-matching procedure, and final wafer results on 2D production patterns. Effectiveness of the optimization strategies was then concluded.