This paper will demonstrate the complementary RegC® and TWINSCANTM solution for improving the OPO by cooptimizing the correction capabilities of the individual tools, respectively. As a consequence, the systematic intra-field fingerprints can be decreased along with the overlay (OVL) error at wafer level. Furthermore, the application could be utilized for extending some of the scanner actuators ranges by inducing a pre-determined signatures. These solutions perfectly fit into the ASML Litho InSight (LIS) product in which feedforward and feedback corrections based on YieldStar overlay and other measurements are used to improve the OPO. While the TWINSCANTM scanner corrects for global distortions (up to third order) - scanner Correctable Errors ( CE), the RegC® application can correct for the None Correctable Errors (NCE) by making the high frequency NCE into a CE with low frequency nature. The RegC® induces predictable deformation elements inside the quartz (Qz) material of the reticle, and by doing so it can induce a desired pre-defined signature into the reticle. The deformation introduced by the RegC® is optimized for the actual wafer print taking into account the scale and ortho compensation by the scanner, to correct for the systematic fingerprints and the wafer overlay. These two applications might be very powerful and could contribute to achieve a better OPO performance.
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Kujan Gorhad, Ofir Sharoni, Vladimir Dmitriev, Avi Cohen, Richard van Haren, Christian Roelofs, Hakki Ergun Cekli, Emily Gallagher, Philippe Leray, Dirk Beyer, Thomas Trautzsch, Steffen Steinert, "Co-optimization of RegC and TWINSCAN corrections to improve the intra-field on-product overlay performance," Proc. SPIE 9778, Metrology, Inspection, and Process Control for Microlithography XXX, 97783D (8 March 2016);