Zernike-based photolithography track modules matching for wafer CDU

Leading-edge DRAM requires tight monitoring of various critical photolithography metrics. A stringent requirement is to control wafer-to-wafer (w2w) critical dimension uniformity (CDU). This necessitates a tight distribution to reduce variability, thereby improving yield. CDU variation can impact the electrical performance of DRAM devices. In high-volume manufacturing (HVM), variation becomes significant due to the numerous toolsets and modules involved in processing each level. Therefore, it is critical to monitor the CDU variation at the critical levels that require sub-nm CDU performance. In Photolithography, Zernike-based modeling is used for overlay metrology and control. In this abstract, we introduce the Zernike approach for CDU modelling and photolithography track modules fingerprinting to minimize variation affecting the device performance. This approach results in more reliable and higher performance devices.