Customized metrology target design to address OPO challenges

On Product Overlay (OPO) challenges are known to be the yield limiters in semiconductor manufacturing processes, as process control performance highly depends on the design and quality of the overlay (OVL) metrology targets. Innovative overlay target designs are needed for OPO reduction, overlay accuracy improvement and measurement robustness enhancement. The Metrology Target Designer (MTD) tool is widely used as an integral simulation method for overlay metrology target design, by co-optimizing lithography and metrology performance. Using this approach, one can simulate and analyze the overlay metrology target’s inherent performance and compatibility to inherent process variations. This paper presents how MTD can boost the Image-Based Overlay (IBO) measurability accuracy and robustness to common process variability issues. A customized MTD solution with Archer™ overlay metrology recipe optimization is developed and proven to address these manufacturing challenges.