Effects of plasma activation on hydrophilic bonding of si and SiO2

Tommi Suni; Kimmo Henttinen; Ilkka Suni; Jari Mäkinen

doi:10.1149/1.1477209

Effects of plasma activation on hydrophilic bonding of si and SiO₂

Tommi Suni (Corresponding Author), Kimmo Henttinen, Ilkka Suni, Jari Mäkinen

VTT Technical Research Centre of Finland

Okmetic Oy

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

263 Citations (Scopus)

Abstract

Low temperature bonding of Si wafers has been studied utilizing RIE-mode plasma activation. The hydrophilic Si and thermally oxidized Si wafers were exposed to N₂, Ar or O₂ plasma prior to bonding in air or vacuum. After plasma treatment the wafers were cleaned in RCA-1 solution and/or DI-water. Strong bonding was achieved at 200°C with all the investigated plasma gases if proper bonding and cleaning procedure is used. Extended RCA-1 cleaning deteriorated the bond strength but a short cleaning improved bonding. We found out that the activation of the thermal oxide has a larger influence on the bond strength than the activation of the native oxide surface in Si/oxide wafer pairs. We suggest that the plasma treatment induces a highly disordered surface structure which enhances the diffusion of the water from the bonded interface. As a result of the plasma exposure the number of the surface OH-groups is highly increased enabling strong bonding at a low temperature.

Original language	English
Article number	G348
Pages (from-to)	22-30
Journal	Journal of the Electrochemical Society
Volume	149
Issue number	6
DOIs	https://doi.org/10.1149/1.1477209
Publication status	Published - 2002
MoE publication type	A1 Journal article-refereed

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title = "Effects of plasma activation on hydrophilic bonding of si and SiO2",

abstract = "Low temperature bonding of Si wafers has been studied utilizing RIE-mode plasma activation. The hydrophilic Si and thermally oxidized Si wafers were exposed to N2, Ar or O2 plasma prior to bonding in air or vacuum. After plasma treatment the wafers were cleaned in RCA-1 solution and/or DI-water. Strong bonding was achieved at 200°C with all the investigated plasma gases if proper bonding and cleaning procedure is used. Extended RCA-1 cleaning deteriorated the bond strength but a short cleaning improved bonding. We found out that the activation of the thermal oxide has a larger influence on the bond strength than the activation of the native oxide surface in Si/oxide wafer pairs. We suggest that the plasma treatment induces a highly disordered surface structure which enhances the diffusion of the water from the bonded interface. As a result of the plasma exposure the number of the surface OH-groups is highly increased enabling strong bonding at a low temperature.",

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AU - Suni, Tommi

AU - Henttinen, Kimmo

AU - Suni, Ilkka

AU - Mäkinen, Jari

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PY - 2002

Y1 - 2002

N2 - Low temperature bonding of Si wafers has been studied utilizing RIE-mode plasma activation. The hydrophilic Si and thermally oxidized Si wafers were exposed to N2, Ar or O2 plasma prior to bonding in air or vacuum. After plasma treatment the wafers were cleaned in RCA-1 solution and/or DI-water. Strong bonding was achieved at 200°C with all the investigated plasma gases if proper bonding and cleaning procedure is used. Extended RCA-1 cleaning deteriorated the bond strength but a short cleaning improved bonding. We found out that the activation of the thermal oxide has a larger influence on the bond strength than the activation of the native oxide surface in Si/oxide wafer pairs. We suggest that the plasma treatment induces a highly disordered surface structure which enhances the diffusion of the water from the bonded interface. As a result of the plasma exposure the number of the surface OH-groups is highly increased enabling strong bonding at a low temperature.

AB - Low temperature bonding of Si wafers has been studied utilizing RIE-mode plasma activation. The hydrophilic Si and thermally oxidized Si wafers were exposed to N2, Ar or O2 plasma prior to bonding in air or vacuum. After plasma treatment the wafers were cleaned in RCA-1 solution and/or DI-water. Strong bonding was achieved at 200°C with all the investigated plasma gases if proper bonding and cleaning procedure is used. Extended RCA-1 cleaning deteriorated the bond strength but a short cleaning improved bonding. We found out that the activation of the thermal oxide has a larger influence on the bond strength than the activation of the native oxide surface in Si/oxide wafer pairs. We suggest that the plasma treatment induces a highly disordered surface structure which enhances the diffusion of the water from the bonded interface. As a result of the plasma exposure the number of the surface OH-groups is highly increased enabling strong bonding at a low temperature.

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DO - 10.1149/1.1477209

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JO - Journal of the Electrochemical Society

JF - Journal of the Electrochemical Society

SN - 0013-4651

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Effects of plasma activation on hydrophilic bonding of si and SiO2

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Effects of plasma activation on hydrophilic bonding of si and SiO₂