Tilted beam scanning electron microscopy, 3-D metrology for microelectronics industry

Valade, Charles; Hazart, J.; Bérard-Bergery, Sébastien; Sungauer, E.; Besacier, M.; Gourgon, C.

doi:10.1117/1.jmm.18.3.034001

Cited by 5 publications

(5 citation statements)

References 14 publications

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“…The tilt (deflection) of the PE beam is performed through the magnetic field generated by the coil at the outlet of the column just above the specimen. Their experimental results are shown in figure 19 of [72]. The results are consistent with the traditional 3D measurement methods.…”

Section: D Surface Reconstructionsupporting

confidence: 69%

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Electron microscopy in semiconductor inspection

Nakamae

2021

Meas. Sci. Technol.

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Currently, semiconductor devices are manufactured in a technology node of several nanometers. Electron microscopy is mainly used in semiconductor inspection in manufacturing stages since accelerated electrons have wavelengths of nanometers or less, and a high spatial resolution can be expected. Among various electron microscopes since the scanning electron microscope (SEM) can observe the sample as it is without processing the sample, the SEM-based inspection instrument is mainly used at each stage of manufacturing the semiconductor device. The paper presents a review of SEM-based electron microscopy in semiconductor inspection. First, an overview of electron microscopy is described to understand the electron-sample interaction, the characteristics of electrons emitted from an irradiated specimen, charging, noise, and so on. Next, application areas such as mask inspection are introduced. Finally, future challenges are discussed.

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Section: D Surface Reconstructionsupporting

confidence: 69%

“…Valade et al [72] have introduced a PE beam tilting mechanism for reconstructing a 3D shape from multiple SEM images. The tilt (deflection) of the PE beam is performed through the magnetic field generated by the coil at the outlet of the column just above the specimen.…”

Section: D Surface Reconstructionmentioning

confidence: 99%

Electron microscopy in semiconductor inspection

Nakamae

2021

Meas. Sci. Technol.

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“…Moreover, 3D imaging based on a tilted electron beam or focused ion beam (FIB) associated with SEM is highly advantageous for the process window evaluation 32 – 35 The former uses the SE signals from different tilted angles to reconstruct the 3D structure, and the latter combines the milling process by FIB with SE imaging simultaneously to make the full volume characterization available. SEM-based 3D imaging exhibits its potential for future application in the process control in microelectron manufacturing.…”

Section: Discussionmentioning

confidence: 99%

Process window improvement for fin cut layer in self-aligned double-patterning process based on backscattered electron imaging

Zhang

Bian

Liu

et al. 2022

J. Micro/Nanopattern. Mats. Metro.

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Background: The self-aligned double-patterning (SADP) process is being used extensively to overcome the lithographic resolution limit in the manufacture of integrated circuits. One use case is fin definition in a fin field-effect transistor. Fin cut layers are applied to modify the fins to the requirements of the device designs.Aim: The traditional secondary electron (SE) imaging exhibits a disadvantage in the process controlling the fin cut layers, and fin damage defects were observed. This work aims to improve the monitoring and controlling capabilities for the process quality of fin cut layers.Approach: A specially designed fin cut process flow and a backscattered electron (BSE) imaging technique are applied to check the process quality. The patterns formed through the fin cut etch and the fin structures are identified and measured simultaneously in one BSE image.Results: By measuring the edge-to-edge distance, pitch walking (PW) of fins, and overlay (OV), the root cause of the fin damage is revealed. The linear fitting model and third-order fitting model are applied to reduce the edge placement error (EPE). The edge distance protecting the "at risk" fin is enlarged from 5.6 to 11.6 nm. The range of the distance is reduced from 11.6 to 8.1 nm, and the improvement in standard deviation is about 33%. Conclusions:This work shows the capability of the BSE imaging technique in the characterization of fin cut layers and the potential in process window improvement restricted to fin damage defects.

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“…The non-destructive methods include spectroscopic-based techniques and SEM-based imaging techniques. [7][8][9] Critical dimension small-angle X-ray spectroscopy (CD-SAXS) has been shown to be capable of measuring the average CD, height, pitch, line-edge roughness, and cross-sectional profile of periodic nanostructures. [10][11][12] Moreover, CD-SEM is one of the most versatile in-line tools for measuring dimensions at any specified position and monitoring dimension variations across the wafer.…”

Section: Introductionmentioning

confidence: 99%

“…High-voltage CD-SEM is specialized for monitoring the 3D features of the HAR holes in HVM, such as the uniformity of the bottom CD and the overlay of the top center and the bottom center. 9,13) In previous work, we demonstrated that backscattered electron (BSE) imaging can identify the cross-sectional profile of the HAR holes. Our experimental results demonstrated that the sidewall angle of the taper geometry and the maximum CD and the depth of the bowing geometry could be quantitatively measured from the cross-sectional profiles we created.…”

Section: Introductionmentioning

confidence: 99%

Deep learning model for 3D profiling of high-aspect-ratio features using high-voltage CD-SEM

Sun¹,

Goto²,

Yamamoto³

et al. 2022

Jpn. J. Appl. Phys.

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High-aspect-ratio (HAR) channel holes were developed for competitive cost-per-bit 3D-NAND memory. High-throughput and in-line monitoring solutions for 3D profiling of the HAR features are the key to improving yields. We previously proposed an exponential model to identify the cross-sectional profile of the HAR features using backscattered electron (BSE) images of a high-voltage critical dimension scanning electron microscopy (CD-SEM). However, the 3D profiling accuracy was insufficient when the depth of the HAR features was far greater than the focus depth of the electron beam. To address this issue, we developed a deep learning (DL) model, which takes account of the aperture angle and the aberration of the electron beam, to predict the 3D profile from BSE images. The predicted cross-sections of the HAR holes with different bowing geometries were compared with field-emission SEM (FE-SEM) measurements. The results show that the DL model provides higher sensitivity than the exponential model does.

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Tilted beam scanning electron microscopy, 3-D metrology for microelectronics industry

Cited by 5 publications

References 14 publications

Electron microscopy in semiconductor inspection

Electron microscopy in semiconductor inspection

Process window improvement for fin cut layer in self-aligned double-patterning process based on backscattered electron imaging

Deep learning model for 3D profiling of high-aspect-ratio features using high-voltage CD-SEM

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