Selective wet etching of Si3N4/SiO2 in phosphoric acid with the addition of fluoride and silicic compounds

Dongwan Seo; Jin Sung Bae; Eunseok Oh; Solbaro Kim; Sangwoo Lim

doi:10.1016/j.mee.2013.12.027

Selective wet etching of Si₃N₄/SiO₂ in phosphoric acid with the addition of fluoride and silicic compounds

Dongwan Seo, Jin Sung Bae, Eunseok Oh, Solbaro Kim, Sangwoo Lim

Department of Chemical and Biomolecular Engineering

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

16 Citations (Scopus)

Abstract

Various additives were added to H₃PO₄ in order to achieve a highly selective wet etching of Si₃N₄ to SiO₂. Fluoride compounds such as HF, NH₄F, and NH ₄HF₂ were added to the H₃PO₄ in order to increase the etch rate of the Si₃N₄. In addition, silicic compounds, including H₂SiF₆, TEOS, and Si(OH)₄, were added to decrease the etch rate of SiO₂. The addition of the fluoride compounds into the H₃PO₄ increased the etch rate of the Si₃N₄, but the etch selectivity of the Si₃N₄ to SiO₂ decreased due to the greater increase in the etch rate of the SiO₂. Both the etch rate and the selectivity showed strong relationships with the amount of fluorine added in H₃PO₄. The addition of TEOS and Si(OH) ₄ increased the etch selectivity by reducing the etch rate of the SiO₂. In particular, the addition of Si(OH)₄ to H ₃PO₄ in the presence of NH₄F and NH ₄HF₂ produced an etch selectivity greater than 10 ⁴.

Original language	English
Pages (from-to)	66-71
Number of pages	6
Journal	Microelectronic Engineering
Volume	118
DOIs	https://doi.org/10.1016/j.mee.2013.12.027
Publication status	Published - 2014 Apr 25

Bibliographical note

Funding Information:
This research was financially supported by OCI Co., Ltd. This work was also supported by Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2009-0093823 ).

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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title = "Selective wet etching of Si3N4/SiO2 in phosphoric acid with the addition of fluoride and silicic compounds",

abstract = "Various additives were added to H3PO4 in order to achieve a highly selective wet etching of Si3N4 to SiO2. Fluoride compounds such as HF, NH4F, and NH 4HF2 were added to the H3PO4 in order to increase the etch rate of the Si3N4. In addition, silicic compounds, including H2SiF6, TEOS, and Si(OH)4, were added to decrease the etch rate of SiO2. The addition of the fluoride compounds into the H3PO4 increased the etch rate of the Si3N4, but the etch selectivity of the Si3N4 to SiO2 decreased due to the greater increase in the etch rate of the SiO2. Both the etch rate and the selectivity showed strong relationships with the amount of fluorine added in H3PO4. The addition of TEOS and Si(OH) 4 increased the etch selectivity by reducing the etch rate of the SiO2. In particular, the addition of Si(OH)4 to H 3PO4 in the presence of NH4F and NH 4HF2 produced an etch selectivity greater than 10 4.",

author = "Dongwan Seo and Bae, {Jin Sung} and Eunseok Oh and Solbaro Kim and Sangwoo Lim",

note = "Funding Information: This research was financially supported by OCI Co., Ltd. This work was also supported by Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2009-0093823 ). ",

year = "2014",

month = apr,

day = "25",

doi = "10.1016/j.mee.2013.12.027",

language = "English",

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T1 - Selective wet etching of Si3N4/SiO2 in phosphoric acid with the addition of fluoride and silicic compounds

AU - Seo, Dongwan

AU - Bae, Jin Sung

AU - Oh, Eunseok

AU - Kim, Solbaro

AU - Lim, Sangwoo

N1 - Funding Information: This research was financially supported by OCI Co., Ltd. This work was also supported by Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2009-0093823 ).

PY - 2014/4/25

Y1 - 2014/4/25

N2 - Various additives were added to H3PO4 in order to achieve a highly selective wet etching of Si3N4 to SiO2. Fluoride compounds such as HF, NH4F, and NH 4HF2 were added to the H3PO4 in order to increase the etch rate of the Si3N4. In addition, silicic compounds, including H2SiF6, TEOS, and Si(OH)4, were added to decrease the etch rate of SiO2. The addition of the fluoride compounds into the H3PO4 increased the etch rate of the Si3N4, but the etch selectivity of the Si3N4 to SiO2 decreased due to the greater increase in the etch rate of the SiO2. Both the etch rate and the selectivity showed strong relationships with the amount of fluorine added in H3PO4. The addition of TEOS and Si(OH) 4 increased the etch selectivity by reducing the etch rate of the SiO2. In particular, the addition of Si(OH)4 to H 3PO4 in the presence of NH4F and NH 4HF2 produced an etch selectivity greater than 10 4.

AB - Various additives were added to H3PO4 in order to achieve a highly selective wet etching of Si3N4 to SiO2. Fluoride compounds such as HF, NH4F, and NH 4HF2 were added to the H3PO4 in order to increase the etch rate of the Si3N4. In addition, silicic compounds, including H2SiF6, TEOS, and Si(OH)4, were added to decrease the etch rate of SiO2. The addition of the fluoride compounds into the H3PO4 increased the etch rate of the Si3N4, but the etch selectivity of the Si3N4 to SiO2 decreased due to the greater increase in the etch rate of the SiO2. Both the etch rate and the selectivity showed strong relationships with the amount of fluorine added in H3PO4. The addition of TEOS and Si(OH) 4 increased the etch selectivity by reducing the etch rate of the SiO2. In particular, the addition of Si(OH)4 to H 3PO4 in the presence of NH4F and NH 4HF2 produced an etch selectivity greater than 10 4.

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