Apply multiple target for advanced gate ADI critical dimension measurement by scatterometry technology

Tzai, Wei-Jhe; Chen, Howard; Huang, Yuhao; Yu, Chun Chi; Lin, Ching-Hung Bert; Wei, Shi-Ming Jeremy; Xu, Z. F.; Yoo, Sungchul; Huang, Chien-Jen; Cheng, Chien‐Chung; Cheng, Juli; Mihardja, Lanny; Chouaib, Houssam

doi:10.1117/12.916234

Cited by 7 publications

(4 citation statements)

References 4 publications

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“…5 to 8 for the SE measurement principle and application examples 5 – 8 The SE signals were also collected in two perpendicular wafer-rotation angles defined by the MHs X and Y pitch directions with respect to SE incident planes. See Fig.…”

Section: Wafer Measurements and Analysesmentioning

confidence: 99%

Flash memory hole etch profile monitoring using x-ray and optical scatterometry

Sorkhabi

Zhang

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

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Memory hole (MH) etching may be one of the most critical and challenging processes in three-dimensional flash processing and integration. As the holes get deep, hole critical dimensions (CDs) can vary significantly during the top-down etch processing, the hole shape can deviate from a round hole, and the centerline of the hole can deviate from a vertical line. These and other complex behaviors depend on not only the process conditions (chemistry, plasma power, bias, temperature, etc.) but also the process chamber history [e.g., radio frequency (RF) hours from preventative maintenance] and how the process chambers are conditioned. In addition, the etch behavior depends on the tier thickness (ONON or OPOP), materials, deposition conditions, and overall wafer topography and shapes. The etch behavior is further related to the die positions on the wafer (center or middle versus edge dies) and the position in the memory cell (close to the edge of the cell or near the center of the cell). To monitor and control the etch behavior, many metrology methods have been developed; these include the etch-back top-view scanning electron microscopy (SEM), tilt SEM, transmission electron microscopy (TEM), and high voltage scanning electron microscopy (HVSEM). These methods are time consuming, and some are destructive, but they have been deemed the ground truth for determining variations in MH etch processes. We report a methodology that combines optical scatterometry (SCD) and small-angle x-ray scatterometry measurements to provide reliable CD profile measurements while meeting the fast-turnaround sampling requirements of high-volume manufacturing.

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Section: Wafer Measurements and Analysesmentioning

confidence: 99%

Flash memory hole etch profile monitoring using x-ray and optical scatterometry

Sorkhabi

Zhang

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

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“…This innovation, in return, brings lots of metrology challenges to the high-volume manufacturing process [3,4]. Spectroscopic ellipsometry is widely used to analyze the changes in intensity of reflected light to determine the shape and dimensions of peorodic structures in semiconductor metrology systems [5][6][7][8][9][10][11]. In 3D flash memory structures, increasing the number of oxide-nitride (ON) pairs leads to higher oscillation frequency and larger spectral range across the wafer, and ultimately results in a lower spectral intensity during spectra collection from metrology tools.…”

Section: Introductionmentioning

confidence: 99%

Leveraging x-ray scatterometry and machine learning to enable robust and high-throughput optical critical dimension metrology for advanced 3D flash memory contact hole profile

Chouaib,

Shi,

Chou

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

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3D flash memory structures have been rapidly developed over the past decade to achieve a high density of stacked memory cells with periodic channel holes across the device. Small deviations of the hole shape can result in considerable variations in device performance and product yield. Understanding the behavior and performance of these high-aspect-ratio structures plays a vital role in such complex vertically stacked structures. Memory hole critical dimensions (CDs) serve as the key information to evaluate the performance of 3D flash memory devices, and these CDs are typically measured by rigorous coupled wave analysis (RCWA) based optical metrology that requires costly and destructive scanning electron microscopy (SEM) or transmission electron microscopy (TEM) reference.Here, we utilize critical dimension smallangle X-ray scatterometry (CD-SAXS) that provides reliable and nondestructive ground truth reference to extract a large amount of detailed hole shape information within a practical time scale compared to traditional lengthy TEM measurements. We leverage advanced data analytics and machine learning techniques to enable an optical critical dimension metrology solution along with the desired amount of reference from CD-SAXS measurements for the memory hole profile investigation. This proposed methodology opens up a new venue for a high-throughput, robust and accurate hole CD profile measurement for the fast-paced and high-volume 3D flash memory manufacturing technology.

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“…Highly precise, accurate, and nondestructive, OCD is becoming widely used for applications such as shallow trench isolation, 4 gate after develop inspection, 5,6 after etch inspection, 6 final inspection, 5 high-k metal gate applications, 5 and recess gate control. Highly precise, accurate, and nondestructive, OCD is becoming widely used for applications such as shallow trench isolation, 4 gate after develop inspection, 5,6 after etch inspection, 6 final inspection, 5 high-k metal gate applications, 5 and recess gate control.…”

Section: Introductionmentioning

confidence: 99%