Nanophotonic identification of defects buried in three-dimensional NAND flash memory devices

Yoon, Jae Woong; Min, Sung−Wook; Kim, Gun Pyo; Kang, Yoonshik; Hahn, Joonseong; Kwon, Oh Jang; Kim, Kyuyoung; Song, Seok Ho

doi:10.1038/s41928-017-0007-7

Cited by 12 publications

(6 citation statements)

References 30 publications

(27 reference statements)

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“…Figure 8a shows the amplitude of the electric field for MIR light from 5-10µm in 1µm increments as it interacts with the structure and Figure 8b shows the simulated spectra (M33 and M34) using Ai Diffract software from 5-10.5µm. While most of the wavelengths don't couple to SPPs, light at 6µm clearly couples to SPPs and other modes (discussed by Yoon, et al 6 ), allowing the electric field to reach the bottom of the WL slit (like a Bragg Plasmonic filter 8 ) and it corresponds to oscillations in the simulated spectra (Figure 7b). This indicates that the channel holes are responsible for "blocking" the coupling of MIR light to SPPs in the 3D NAND array structure.…”

Section: Fdtd and Rwca Simulation Results: 3d Nand Array Structure Wi...mentioning

confidence: 88%

“…The plasma frequency is defined as when the real part of the dielectric function equals zero and becomes negative for lower frequencies 5 . For tungsten, that wavelength is 942nm and it has been shown with simulation and measurements that IR light lower than this frequency can excite "diffraction-assisted volume plasmonic resonance" in 3D NAND structures post metal gate replacement with word line slit pitches less than one micron that can propagate in the z direction to the bottom of the WL slit 6 .…”

Section: Initial W-recess Mir Rcwa Simulations and Motivation For Tar...mentioning

confidence: 99%

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Measurement of W-recess profile in an advanced node 3D NAND device with IRCD technology utilizing a specialized design-rule compliant target

Keller

Chen

Grynko

et al. 2023

Metrology, Inspection, and Process Control XXXVII

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The W-Recess step for 3D NAND replacement gate process currently has no in-line process control solution. W replacement renders the structure opaque in the ultraviolet/visible/near-infrared (UV/VIS/NIR) region beyond just a few tier layers in the most advanced 3D NAND devices. Additionally, increased word line (WL) slit pitch scaling further reduces the already minimal optical signal from the top of the structure. Through finite-difference time-domain (FDTD) and optical critical dimension (OCD) simulations, we show that a specially designed, design rule-compliant (that is, possessing a slit pitch matching the device) ellipsometry target permits mid-IR light to completely penetrate through oxide metal (OM) pairs, enabling measurement of the W-Recess Z-profile. Furthermore, recent experimental data measured on the designed target in >200 pair 3D NAND node prove that mid-IR light has sensitivity to the slit bottom. An OCD model was developed and showed good design of experiment (DOE) discrimination capability and reference correlation.

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Section: Fdtd and Rwca Simulation Results: 3d Nand Array Structure Wi...mentioning

confidence: 88%

Section: Initial W-recess Mir Rcwa Simulations and Motivation For Tar...mentioning

confidence: 99%

Measurement of W-recess profile in an advanced node 3D NAND device with IRCD technology utilizing a specialized design-rule compliant target

Keller

Chen

Grynko

et al. 2023

Metrology, Inspection, and Process Control XXXVII

View full text Add to dashboard Cite

show abstract

“…The schematic of a feasible experimental setup is shown in Figure S1. However, things get worse when the wavelength of the source is much larger than the size of twin lines (which is always the case in the scope of optical wafer defect inspection. − ), i.e., the diffraction barrier starts to play the key role, leading to the severely distorted light field. To tackle this problem, we introduce the concept of OPC, which is a technique used in inverse lithography at advanced technology nodes, to our c-SIM.…”

Section: Methodsmentioning

confidence: 99%

Optical Far-Field Detection of Sub-λ/14 Wide Defects by Conjugate Structured Light-Field Microscopy (c-SIM)

Zhang,

Liu,

Jiang

et al. 2023

ACS Photonics

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Optical far-field detection and imaging of deep-subwavelength objects in a large-area wafer is challenging because of the well-known diffraction barrier and weak Rayleigh scattering. Although the scattering signal of deep subwavelength defects can be enhanced by various methods, such as using a high full-well-capacity camera and increasing the exposure time, the accurate classification of various defects and the precise positioning of defects in a subwavelength domain is rather challenging. In this letter, we report a theoretical framework that the optical bright-field imaging microscopy, coupled with an optical proximity correction-based structured light-field illumination mode, could pinpoint and classify various sub-λ/14 wide defects in a subwavelength domain in a large-area wafer. The underlying physics is that the illuminated structured light field, which is customized to mimic the geometrical feature of the background pattern in the wafer, creates the defect-induced breakdown of geometrical and electromagnetic symmetry. We believe that this work not only paves the route for optical wafer defect inspection and classification at advanced technology nodes but also could potentially be extended to many other areas, such as biosensing, lithographic mask inspection, material characterization, and nanoscale metrology.

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“…However, they may lose sensitivity for some defects, for example, deeply buried defects. Yoon et al proposed an innovative method that takes advantage of the sample side rather than the instrument side [166]. In their proposal, the sample under investigation is a 3D NAND (NOT AND) flash memory, which has hierarchical structures with micrometer-scale height, 100 nm-scale overall period, and a minimal CD on the order of 10 nm; as shown in figures 12(a) and (b).…”

Section: Defect Inspection Using Hyperbolic Bloch Modesmentioning

confidence: 99%

Optical wafer defect inspection at the 10 nm technology node and beyond

Zhu¹,

Liu²,

Xu³

et al. 2022

Int. J. Extrem. Manuf.

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The growing demand for electronic devices, smart devices, and the Internet of Things constitutes the primary driving force for marching down the path of decreased critical dimension and increased circuit intricacy of integrated circuits. However, as sub-10 nm high-volume manufacturing is becoming the mainstream, there is greater awareness that defects introduced by original equipment manufacturer components impact yield and manufacturing costs. The identification, positioning, and classification of these defects, including random particles and systematic defects, are becoming more and more challenging at the 10 nm node and beyond. Very recently, the combination of conventional optical defect inspection with emerging techniques such as nanophotonics, optical vortices, computational imaging, quantitative phase imaging, and deep learning is giving the field a new possibility. Hence, it is extremely necessary to make a thorough review for disclosing new perspectives and exciting trends, on the foundation of former great reviews in the field of defect inspection methods. In this article, we give a comprehensive review of the emerging topics in the past decade with a focus on three specific areas: (1) the defect detectability evaluation, (2) the diverse optical inspection systems, and (3) the post-processing algorithms. We hope, this work can be of importance to both new entrants in the field and people who are seeking to use it in interdisciplinary work.

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Nanophotonic identification of defects buried in three-dimensional NAND flash memory devices

Cited by 12 publications

References 30 publications

Measurement of W-recess profile in an advanced node 3D NAND device with IRCD technology utilizing a specialized design-rule compliant target

Measurement of W-recess profile in an advanced node 3D NAND device with IRCD technology utilizing a specialized design-rule compliant target

Optical Far-Field Detection of Sub-λ/14 Wide Defects by Conjugate Structured Light-Field Microscopy (c-SIM)

Optical wafer defect inspection at the 10 nm technology node and beyond

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