Advanced overlay control algorithms utilizing Run-to-Run (R2R) CPE can be used to reduce the overlay signatures on product in High Volume Manufacturing (HVM) environments. In this paper, we demonstrate the results of a R2R CPE control scheme in HVM. The authors show an improvement up to 20% OPO Mean+3Sigma values on several critical immersion layers at the 28nm and 14 nm technology nodes, and a reduction of out-of-spec residual points per wafer (validated on full map). These results are attained by closely tracking process tool signature changes by means of APC, and with an affordable metrology load which is significantly smaller than full wafer measurements.
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Lokesh Subramany, Woong Jae Chung, Karsten Gutjahr, Miguel Garcia-Medina, Christian Sparka, Lipkong Yap, Onur Demirer, Ramkumar Karur-Shanmugam, Brent Riggs, Vidya Ramanathan, John C. Robinson, Bill Pierson, "HVM capabilities of CPE run-to-run overlay control," Proc. SPIE 9424, Metrology, Inspection, and Process Control for Microlithography XXIX, 94241V (19 March 2015);