Realizing EUV photomask defectivity qualification by actinic mask review system

The EUV reticle masking process has enabled the creation of smaller and more intricate integrated circuits, which are essential components of modern electronic devices. However, ensuring defect-free control and evaluation in the cutting-edge EUV reticle masking process is a challenging task. Currently, every potential defect must be judged by wafer printing assessment for almost 3 days, which can be both time-consuming and expensive, and even commercial approaches are incapable of meeting the demands of high-volume manufacturing. In this paper, we successfully developed the EUV Actinic Mask Review System (AMRS) to emulate wafer printability behaviors, utilizing a stable LPP EUV source with over 95% available time and a specialized TSMC-made SMO to achieve high throughput for more than 80 sites/hr. In addition, various EUV resist models have been developed to emulate the risk defect printing assessment with good matching results, and an in-house automation EUV defect analysis platform was developed to achieve fast and accurate areal image measurement. With this solution, all EUV repaired and potential defects, including 18nm HP L/S, ML defects, and even through EUV pellicle defects, can be addressed in technology nodes N5, N3, and beyond N3, on the brand-new actinic review platform. The development of the EUV Actinic Mask Review System represents a significant advancement in ensuring the quality and reliability of semiconductor devices. It provides a practical solution to the challenges posed by the EUV reticle masking process and enables the production of defect-free integrated circuits, paving the way for the continued innovation and progress of the semiconductor industry.