Measurability analysis of the HAR structure in 3D memory by T-SAXS simulation

Sasaki, Kaori; Hashimoto, Takaki; Kuo, Yen‐Ting; Tsukada, Hiroshi; Tanizaki, Hiroyuki

doi:10.1117/12.2582070

Cited by 4 publications

(5 citation statements)

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“…[4][5][6]9,[13][14][15][16] The treatment for high aspect ratio structures including two dimensional (2D) arrays of holes and 1D trenches encountered in advanced memory applications in 3D-NAND and a DRAM memory has received relatively less attention. [16][17][18][19][20] To date, however, it is only these latter structures that are suitable for measurement with XCD within fabs using available compact x-ray sources suitable for inline metrology rather than R&D measurements at national synchrotron facilities. 11 Alternatively, some critical parameters such as the average tilt of the holes and slits, as well as the etch quality can be accurately and precisely determined directly without calibration or sophisticated modeling.…”

Section: Introductionmentioning

confidence: 99%

“… – 6 , 9 , 13 – 16 The treatment for high aspect ratio structures including two dimensional (2D) arrays of holes and 1D trenches encountered in advanced memory applications in 3D- nand and a DRAM memory has received relatively less attention 16 – 20 To date, however, it is only these latter structures that are suitable for measurement with XCD within fabs using available compact x-ray sources suitable for inline metrology rather than R&D measurements at national synchrotron facilities 11 …”

Section: Introductionmentioning

confidence: 99%

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Inline metrology of high aspect ratio hole tilt and center line shift using small-angle x-ray scattering

Gin

Wormington

Amasay

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

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High aspect ratio (HAR) structures found in three-dimensional NAND memory structures have unique process control challenges. The etch used to fabricate channel holes several microns deep with aspect ratios beyond 50:1 is a particularly challenging process that requires exquisitely accurate and precise control. It is critical to carefully analyze multiple aspects of the etch process, such as hole profile, tilt, uniformity, and quality during development and production. X-ray critical dimension (XCD) metrology, which is also known as critical dimension small-angle x-ray scattering, is a powerful technique that can provide valuable insights on the arrangement, shape, and size of periodic arrays of HAR features. XCD is capable of fast, nondestructive measurements in the cell-area of production wafers, making XCD ideal for in-line metrology. Through several case studies, we will show that XCD can be used to accurately and precisely determine key properties of holes etched into hard mask, multilayer oxide/nitride film stacks and slit trenches. We show that the measurement of hole and slit tilt can be achieved without the aid of a structural model using a Fast Tilt methodology that provides sub-nanometer precision. Measurements were performed across several production wafers to determine the etch uniformity and quality. Particular attention was given at the edge of the wafers to account for large variations observed. In addition, we used a detailed physical model to characterize the HAR structures beyond linear tilt. This approach provides a more complete picture of the etch quality.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Inline metrology of high aspect ratio hole tilt and center line shift using small-angle x-ray scattering

Gin

Wormington

Amasay

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

View full text Add to dashboard Cite

show abstract

“…These dimensions create significant challenges for incumbent metrologies based on scanning electron microscopy and optical scatterometry, especially for nanostructures with high aspect ratio (HAR) and/or with structures inside buried layers. 2 Now, the number of layers in memory chips, such as 3D NAND, is well over 200. This provides an entrance point for the x-ray based metrology.…”

Section: Introductionmentioning

confidence: 99%

“…When the smallest, or “critical,” dimensions are <10 nm, the acceptable tolerance will be much <1 nm. These dimensions create significant challenges for incumbent metrologies based on scanning electron microscopy and optical scatterometry, especially for nanostructures with high aspect ratio (HAR) and/or with structures inside buried layers 2 . Now, the number of layers in memory chips, such as 3D NAND, is well over 200.…”

Section: Introductionmentioning

confidence: 99%

Review of the key milestones in the development of critical dimension small angle x-ray scattering at National Institute of Standards and Technology

Kline

Jones

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

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An x-ray scattering based metrology was conceived over 20 years ago as part of a collaboration between National Institute of Standards and Technology (NIST) and International Business Machines Corporation (IBM) to evaluate the performance of lithographic patterning materials for the semiconductor industry. This methodology treated a periodic array of lithographic structures as a diffraction grating and focused on extracting the physical dimensions of the structures in the grating by analyzing the diffraction patterns. In the early stages of the work the focus was on developing the transmission small-angle x-ray scattering (tSAXS) as a metrology tool to measure the critical dimensions (CD) of the lithographic features vital to the integrated circuit chip fabrication. Later, the focus shifted to include grazing incident small-angle x-ray scattering and x-ray reflectivity as parts of the CD metrology tool due to their unique capabilities. Frequently the term critical dimension small-angle x-ray scattering (CDSAXS) has been used as a synonym for the metrology of using tSAXS for CD measurements without mentioning transmission. Various milestones in the CDSAXS development are reviewed in this article together with some prospects regarding the future growth of x-ray-based metrology for complex three-dimensional nanostructures important to semiconductor industries.

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“…Micrometer-scale high-aspect-ratio (HAR) structures are widely used in the fields of MEMS and three-dimensional integrated circuits (3D-IC) to improve lateral integration density, energy storage potency, and signal transmission efficiency. The depth of HAR structures is a key functional parameter that significantly impacts sensor performance [1][2][3]. In 2014, O. Fursenko, J. Bauer et al used the KLA-Tencor Spectra Fx 200 wafer metrology tool to measure the depth of HAR structures.…”

Section: Introductionmentioning

confidence: 99%

Optical method for depth measurement of high aspect ratio 3D microstructure

Zizheng,

Chengpei,

Xinlei

et al. 2023

Optical Metrology and Inspection for Industrial Applications X

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Measurability analysis of the HAR structure in 3D memory by T-SAXS simulation

Cited by 4 publications

References 0 publications

Inline metrology of high aspect ratio hole tilt and center line shift using small-angle x-ray scattering

Inline metrology of high aspect ratio hole tilt and center line shift using small-angle x-ray scattering

Review of the key milestones in the development of critical dimension small angle x-ray scattering at National Institute of Standards and Technology

Optical method for depth measurement of high aspect ratio 3D microstructure

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