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Differences in imaging behaviour between lithographic systems of the same wavelength result in variations of optical proximity effects (OPE). A way to compensate these irregularities is through scanner tuning. In scanner tuning, scanner specific adjustments are obtained through the determination of scanner knob sensitivities of relevant structures followed by an optimization to adjust the structure CD values to be close to the desired values. Traditionally, scanner tuning methods have relied heavily on wafer-based CD metrology to characterize both the initial mismatch as well as the sensitivities of CDs to the scanner tuning knobs. These methods have proven very successful in reducing the mismatch, but their deployment in manufacturing has been hampered by the metrology effort. In this paper, we explore the possibility of using ASML's LithoTuner PatternMatcher FullChip (PMFC) computational lithography tool to reduce the dependence on wafer CD metrology. One tuning application using flexray illumination instead of traditional scanner knobs is presented in this work; in this application individual critical features in wafer printing are improved without affecting other sites. The limited impact of tuning on other structures is verified through full-chip LMC runs. Potential uses of this technology are for process transfers from one fab to another where the OPC signature in the receiving fab is similar but not identical to the signature of the originating fab. The tuning application is investigated with respect to its applicability in a production environment, including further metrology effort reduction by using scatterometry tools.

For the high volume manufacturing at the 45nm node and beyond it is crucial to match the OPC behaviour of all scanners used at a given process step. For this task the ASML LithoTuner PatternMatcher software was used. LithoTuner PatternMatcher is a tool to improve the proximity differences between a reference scanner and one or more so called 'to be matched' scanners. The optimization uses the concept of sensitivities of CDs of critical features towards adjustable scanner parameters in combination with the delta CD's of those critical features. To perform the scanner matching it is very important to have accurate and repeatable CD data. Therefore we investigated the use of scatterometry as a replacement for the traditional CDSEM measurement. Scatterometry significantly enhances the measurement precision while simultaneously reduces the measurement time. In a first step we determined the sensitivities of the structures by measuring the CD response to small perturbations of the individual scanner parameter settings. CD through pitch and repeating 2 dimensional line end structures were measured using the ASML YieldStar tool and a Hitachi CDSEM. The scatterometry- and CDSEM based sensitivities of the scanner parameter settings are compared. Finally a scanner matching based on both sets of sensitivities has been performed. In this article we will show that both methods are suited to perform the scanner matching. We will also present the differences between the two sets of sensitivities obtained with scatterometry and CDSEM. At the end we will present the results of the tool matching and show the results of a cross check. In the cross check sensitivities obtained with the use of scatterometry were used for the scanner matching next to SEM metrology used for verification.