Gaining insight into critical dimension sensitivity and uniformity in an SADP based advanced DRAM cut process using virtual fabrication

Qingpeng Wang; Benjamin Vincent; Joseph Ervin

doi:10.1117/12.2613613

25 May 2022 Gaining insight into critical dimension sensitivity and uniformity in an SADP based advanced DRAM cut process using virtual fabrication

Qingpeng Wang, Benjamin Vincent, Joseph Ervin

Author Affiliations +

Proceedings Volume 12055, Advances in Patterning Materials and Processes XXXIX; 120550M (2022) https://doi.org/10.1117/12.2613613
Event: SPIE Advanced Lithography + Patterning, 2022, San Jose, California, United States

Abstract

In this paper, an active area cut approach using a self-aligned double patterning process for advanced DRAM was studied using virtual fabrication. The mandrel critical dimension, mandrel line edge roughness, mandrel overlays and spacer thicknesses were selected as input process variables in the virtual DOE to investigate their sensitivity to the final fin cut head to head (HTH) critical dimension (CD) and its uniformity (CDU). For the mean CD, the study illustrates that maximum mean CD can be obtained at a combination of mandrel CDs when the mandrel overlays approach a value of zero. The overlay of mandrel 1 in both the X and Y direction appears to have a stronger impact on the mean CD than the overlay of mandrel 2. We determined that the mean HTH CD decreased 0.44 and 0.93 nm, respectively, when the spacer 1 and spacer 2 thickness were increased by 1 nm. Our simulations also show that CDU is strongly impacted by the mandrel line edge roughness (LER), at a sensitivity of 1.16 nm / 1 nm. The lowest variation and maximum mean CD can be obtained using particular combinations of mandrel 1 CDs and spacer thicknesses. Overlays do not impact the final HTH CDU. From our study, we can provide clear guidance to developers about the relationship between process parameters and final HTH CD and CDU, showing that the integrated process should be centered at particular conditions to obtain an optimal process window.

Conference Presentation

Citation Download Citation

Qingpeng Wang, Benjamin Vincent, and Joseph Ervin "Gaining insight into critical dimension sensitivity and uniformity in an SADP based advanced DRAM cut process using virtual fabrication", Proc. SPIE 12055, Advances in Patterning Materials and Processes XXXIX, 120550M (25 May 2022); https://doi.org/10.1117/12.2613613

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