Oxide regrowth mechanism during silicon nitride etching in vertical 3D NAND structures

Taehyeon Kim; Changjin Son; Taegun Park; Sangwoo Lim

doi:10.1016/j.mee.2019.111191

Oxide regrowth mechanism during silicon nitride etching in vertical 3D NAND structures

Taehyeon Kim, Changjin Son, Taegun Park, Sangwoo Lim

Department of Chemical and Biomolecular Engineering

Research output: Contribution to journal › Article › peer-review

18 Citations (Scopus)

Abstract

It is essential to selectively etch Si₃N₄ in the presence of SiO₂ during the process of fabricating vertical 3D NAND structures. SiO₂ etching inhibitors can be added to H₃PO₄ to increase Si₃N₄-to-SiO₂ etch selectivity; however, the addition of SiO₂ etching inhibitors to H₃PO₄ generates oxide regrowth issues on the SiO₂ etch stop layers of the Si₃N₄/SiO₂ pair-layer stacks. It is also observed that generation rate of Si₃N₄ etching byproduct as well as addition of SiO₂ etching inhibitor strongly affects oxide regrowth behavior on the Si₃N₄/SiO₂ multipair-layered structure. In addition, the limited mass transfer of Si₃N₄ etching byproduct produced heavier amounts of oxide regrowth on the corners of the SiO₂ etch stop layers and at the stack structure bottoms. Modification of surface reactivity and the adhesion properties of silica-like monomers on the SiO₂ etch stop layer may be important factors for reducing oxide regrowth during the selective etching of Si₃N₄.

Original language	English
Article number	111191
Journal	Microelectronic Engineering
Volume	221
DOIs	https://doi.org/10.1016/j.mee.2019.111191
Publication status	Published - 2020 Jan 15

Bibliographical note

Funding Information:
This work was supported by the Ministry of Trade, Industry & Energy ( 10080628 ) and Korea Semiconductor Research Consortium Support Program for the development of future semiconductor devices.

Publisher Copyright:
© 2019 Elsevier B.V.

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Atomic and Molecular Physics, and Optics
Condensed Matter Physics
Surfaces, Coatings and Films
Electrical and Electronic Engineering

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10.1016/j.mee.2019.111191

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title = "Oxide regrowth mechanism during silicon nitride etching in vertical 3D NAND structures",

abstract = "It is essential to selectively etch Si3N4 in the presence of SiO2 during the process of fabricating vertical 3D NAND structures. SiO2 etching inhibitors can be added to H3PO4 to increase Si3N4-to-SiO2 etch selectivity; however, the addition of SiO2 etching inhibitors to H3PO4 generates oxide regrowth issues on the SiO2 etch stop layers of the Si3N4/SiO2 pair-layer stacks. It is also observed that generation rate of Si3N4 etching byproduct as well as addition of SiO2 etching inhibitor strongly affects oxide regrowth behavior on the Si3N4/SiO2 multipair-layered structure. In addition, the limited mass transfer of Si3N4 etching byproduct produced heavier amounts of oxide regrowth on the corners of the SiO2 etch stop layers and at the stack structure bottoms. Modification of surface reactivity and the adhesion properties of silica-like monomers on the SiO2 etch stop layer may be important factors for reducing oxide regrowth during the selective etching of Si3N4.",

author = "Taehyeon Kim and Changjin Son and Taegun Park and Sangwoo Lim",

note = "Funding Information: This work was supported by the Ministry of Trade, Industry & Energy ( 10080628 ) and Korea Semiconductor Research Consortium Support Program for the development of future semiconductor devices. Publisher Copyright: {\textcopyright} 2019 Elsevier B.V.",

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doi = "10.1016/j.mee.2019.111191",

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AU - Kim, Taehyeon

AU - Son, Changjin

AU - Park, Taegun

AU - Lim, Sangwoo

N1 - Funding Information: This work was supported by the Ministry of Trade, Industry & Energy ( 10080628 ) and Korea Semiconductor Research Consortium Support Program for the development of future semiconductor devices. Publisher Copyright: © 2019 Elsevier B.V.

PY - 2020/1/15

Y1 - 2020/1/15

N2 - It is essential to selectively etch Si3N4 in the presence of SiO2 during the process of fabricating vertical 3D NAND structures. SiO2 etching inhibitors can be added to H3PO4 to increase Si3N4-to-SiO2 etch selectivity; however, the addition of SiO2 etching inhibitors to H3PO4 generates oxide regrowth issues on the SiO2 etch stop layers of the Si3N4/SiO2 pair-layer stacks. It is also observed that generation rate of Si3N4 etching byproduct as well as addition of SiO2 etching inhibitor strongly affects oxide regrowth behavior on the Si3N4/SiO2 multipair-layered structure. In addition, the limited mass transfer of Si3N4 etching byproduct produced heavier amounts of oxide regrowth on the corners of the SiO2 etch stop layers and at the stack structure bottoms. Modification of surface reactivity and the adhesion properties of silica-like monomers on the SiO2 etch stop layer may be important factors for reducing oxide regrowth during the selective etching of Si3N4.

AB - It is essential to selectively etch Si3N4 in the presence of SiO2 during the process of fabricating vertical 3D NAND structures. SiO2 etching inhibitors can be added to H3PO4 to increase Si3N4-to-SiO2 etch selectivity; however, the addition of SiO2 etching inhibitors to H3PO4 generates oxide regrowth issues on the SiO2 etch stop layers of the Si3N4/SiO2 pair-layer stacks. It is also observed that generation rate of Si3N4 etching byproduct as well as addition of SiO2 etching inhibitor strongly affects oxide regrowth behavior on the Si3N4/SiO2 multipair-layered structure. In addition, the limited mass transfer of Si3N4 etching byproduct produced heavier amounts of oxide regrowth on the corners of the SiO2 etch stop layers and at the stack structure bottoms. Modification of surface reactivity and the adhesion properties of silica-like monomers on the SiO2 etch stop layer may be important factors for reducing oxide regrowth during the selective etching of Si3N4.

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Oxide regrowth mechanism during silicon nitride etching in vertical 3D NAND structures

Abstract

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All Science Journal Classification (ASJC) codes

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