Evaluation of deep learning model for 3D profiling of HAR features using high-voltage CD-SEM

Sun, Wei; Goto, Yasunori; Yamamoto, Takahiro; Hitomi, Keiichiro

doi:10.1117/12.2592052

Cited by 7 publications

(6 citation statements)

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“…In the case of in-line scanning electron microscopy (SEM), it is widely used for critical dimension (CD) measurements from top-down view images. The applications of CD-SEM also extend to profile measurements of HAR structure in 3D NAND as reported by Sun et al [1]. However, the total depth of the measurement structures reaches only 3.0μm.…”

Section: Introductionmentioning

confidence: 60%

Global tilt measurement on irregular PIL supporting patterns in 3D NAND memory

Lin,

Lee,

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

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3D NAND flash memory stacks cells vertically in multiple layers. One of the critical processes in chip-making is slit trench landing control since the word-line gate replacement of silicon nitride films and the isolation of plural memory blocks are through the means of slit structure. However, during the gate of silicon nitride removal in slit trenches, the architecture of memory blocks may get collapse due to lacking sufficient supporting patterns surrounding around the slit trenches. For better silicon nitride removal control, there are various irregular patterns of dummy pillars (PIL) designed in as supporting structures to provide better mechanical property which can prevent memory blocks from collapsing while removing silicon nitride in gate replacement processing. Hence, an effective measurement to indicate the bottom shifting of PIL during the etching recipe optimization is necessary to be developing. In this work, we demonstrate the employment of the small angle X-ray scattering (SAXS) technology with global tilt extraction (GTE) that successfully predicts PIL landing location displacement, which matches with destructive gauging data. The GTE is a modeless method to determine global title, i.e., center line shifting (CLS) of the bottom relative to the topmost on the target pattern. GTE is developing to be a reliable means for in-line process monitoring as well as managing to apply in PIL etching recipe optimization for 3D NAND development.

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Section: Introductionmentioning

confidence: 60%

Global tilt measurement on irregular PIL supporting patterns in 3D NAND memory

Lin,

Lee,

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

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show abstract

“…In the case of in-line scanning electron microscopy (SEM), it is widely used for critical dimension (CD) measurements from top-down view images. The applications of CD-SEM also extend to profile measurements of HAR structure in 3D NAND as reported by Sun et al [2]. However, the total depth of the measurement structures reaches only 3.0μm.…”

Section: Introductionmentioning

confidence: 60%

Global tilt extraction for BEOL contact landing displacement control

Lin,

Lee,

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

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3D NAND has become mainstream storage devices in a past decade and the stacking cell layers now reaches to more than 300 layers. As stack gets higher, more and more etching process challenges are brought into 3D NAND high aspect ratio (HAR) structure patterning. Among the HAR etching processes, the deep contact etches in the back-end-of-line (BEOL) are patterned after other HAR structures such as channel holes, deep trenches or other dummy patterns. Any unexpected overlapping of deep contacts with other patterns would lead to fatal product yield loss due to such wrong circuit connections and leakage currents. Hence, a reliable and fast monitoring methodology for profile tilting is extremely important.In this article, it is first time to demonstrate the employment of the small angle X-ray scattering (SAXS) technology and global tilt extraction (GTE) by using Axion @TM from KLA-Tencor to measure bottom tilting behavior for deep contact structure in 200+ layers of 3D NAND product. As regarding for the necessaries of gathering layout pitch, detail film stacks and hole dimensions by regular model base approach, the GTE is a pure modeless method by using X-ray scattering images to determine the central point shifting of the bottom relative to the topmost on the target pattern. With GTE help, the development cycle time for etch recipe tuning and BEOL process optimization is effectively improved, as well as demonstrating better process control to sustain product yield.

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“…This way, the excess material on defective features can be etched, or missing material can be deposited with sufficient precision. 5 Deep learning approaches [6][7][8][9] have already demonstrated almost flawless defect detection results. However, the extraction of repair shapes is still a challenge today.…”

Section: Introductionmentioning

confidence: 99%

3D mask defect and repair simulation based on SEM images

Medvedev

Evanschitzky²,

Erdmann³

2022

37th European Mask and Lithography Conference

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Background: In practice, manufactured lithography masks come with a certain number of unintended defects. Therefore, mask fabrication is accompanied by a subsequent repair, performed via etching or material deposition by a gas-assisted focused electron beam. Aim:The goal of this work is to assess the lithographic impact of mask defects and corresponding repair by simulations.Approach: For this purpose, a novel analytical method was developed to retrieve exact repair shapes from scanning electron microscope (SEM) images of the mask patterns. A developed method, based on computer vision and image processing, is combined with a dedicated artificial intelligence (AI) network trained to detect defective contact and line/space patterns from mask SEM images. Lithography simulations were done for 3D masks derived from the real SEM images.Results: 3D masks with the 13 nm lines and 18 nm contact holes are simulated, and corresponding aerial images are computed. Different typical defects are investigated and demonstrate the robustness and effectiveness of the developed software. Conclusions:The developed analytical algorithm demonstrates a stable and accurate extraction of repair shapes from given mask SEM images. Using our simulation procedure, the impact of each defect from a variety of SEM images was assessed, and lithographic performance after a repair was predicted. In the simulations, the determination of the optimum repair shape is implemented as a two-step procedure providing a large overlap of process windows of defect-free and repaired features, hence high-quality lithography output.

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Evaluation of deep learning model for 3D profiling of HAR features using high-voltage CD-SEM

Cited by 7 publications

References 0 publications

Global tilt measurement on irregular PIL supporting patterns in 3D NAND memory

Global tilt measurement on irregular PIL supporting patterns in 3D NAND memory

Global tilt extraction for BEOL contact landing displacement control

3D mask defect and repair simulation based on SEM images

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