Novel ATHENA mark design to enhance alignment quality in double patterning with spacer process

L. W. Chen; Mars Yang; Elvis Yang; T. H. Yang; K. C. Chen; Chih-Yuan Lu

doi:10.1117/12.846014

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3 March 2010 Novel ATHENA mark design to enhance alignment quality in double patterning with spacer process

L. W. Chen, Mars Yang, Elvis Yang, T. H. Yang, K. C. Chen, Chih-Yuan Lu

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Proceedings Volume 7640, Optical Microlithography XXIII; 764020 (2010) https://doi.org/10.1117/12.846014
Event: SPIE Advanced Lithography, 2010, San Jose, California, United States

Abstract

DPS (Double Patterning with Spacer) has been one of the most promising solutions in flash memory device manufacturing. Apart from the process complexity inherent with the DPS process, the DPS process also requires more engineering efforts on alignment technique compared to the single patterning. Since the traditional alignment marks defined by the core mask has been altered hence the alignment mark recognition could be challenging for the subsequent process layers. This study characterizes the process influence on the traditional ASML VSPM (Versatile Scribelane Primary Marks) alignment mark, and various types of sub-segmentations within VSPM marks were carried out to enable the alignment and find out the best performing alignment marks. The design of the transverse and vertical sub-segmentations within the VSPM marks is aimed to enhance the alignment signal strength and mark detectability. Alignment indicators of WQ (Wafer Quality), MCC (Multiple Correlation Coefficient) and ROPI (Residual Overlay Performance Indicator) were used to judge the alignment performance and stability. A good correlation was established between sub-segmentations and wafer alignment signal strength.

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L. W. Chen, Mars Yang, Elvis Yang, T. H. Yang, K. C. Chen, and Chih-Yuan Lu "Novel ATHENA mark design to enhance alignment quality in double patterning with spacer process", Proc. SPIE 7640, Optical Microlithography XXIII, 764020 (3 March 2010); https://doi.org/10.1117/12.846014

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