Investigation of device overlay variation and control metrology in 3D-NAND process

Yu-Lin Liu; Li-Ting Chang; Kai-Bang Hsu; Mars Yang; Elvis Yang; T. H. Yang; K. C. Chen

doi:10.1117/12.2657015

27 April 2023 Investigation of device overlay variation and control metrology in 3D-NAND process

Yu-Lin Liu, Li-Ting Chang, Kai-Bang Hsu, Mars Yang, Elvis Yang, T. H. Yang, K. C. Chen

Proceedings Volume 12496, Metrology, Inspection, and Process Control XXXVII; 1249628 (2023) https://doi.org/10.1117/12.2657015
Event: SPIE Advanced Lithography + Patterning, 2023, San Jose, California, United States

Conference Poster

Abstract

3D-NAND manufacturers are racing to increase the storage capacity by increasing the number of stacked layers. As the increase of the number of stacked layers, complex process, films stress and deep-etch tilting effects were observed to affect the device overlay control significantly. Traditional optical overlay metrology via scribe-lane image based overlay (IBO) has its constraint to entirely reflecting in-device overlay behavior because of the differences on pattern density, film stack and stress to memory array. In this study, Patterned Wafer Geometry (PWG) tool was adopted to collect wafer shape step-by-step. The in-plane deviation (IPD) and Gen4 overlay derived from wafer shape was used as efficient indexes to distinguish which metrology is representative of indevice overlay for critical layers. High voltage scanning electron microscope (HV-SEM) and optical scatterometry critical dimension measurement (SCD) were adopted separately combining with traditional scribe-lane IBO metrology for in-device overlay improvement through applying non-zero offset (NZO) overlay compensation at different photo layers.

Citation Download Citation

Yu-Lin Liu, Li-Ting Chang, Kai-Bang Hsu, Mars Yang, Elvis Yang, T. H. Yang, and K. C. Chen "Investigation of device overlay variation and control metrology in 3D-NAND process", Proc. SPIE 12496, Metrology, Inspection, and Process Control XXXVII, 1249628 (27 April 2023); https://doi.org/10.1117/12.2657015

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