Compensation of Surface Roughness Using an Au Intermediate Layer in a Cu Direct Bonding Process

Noma, Hirokazu; Kamibayashi, Takumi; Kuwae, Hiroyuki; Suzuki, N.; Nonaka, Takamasa; Shoji, Shuichi; Mizuno, Jun

doi:10.1007/s11664-018-6428-x

Cited by 12 publications

(2 citation statements)

References 24 publications

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“…Different capabilities of passivation materials are compared in Figure 11(b), and wafer-level bonding sample SAM images are shown in Figure 11(c). Au passivation is applied in research (Liu et al , 2021a; Noma et al , 2018), and the hybrid bonding process with Au-passivated Cu and diluted hydrofluoric acid-treated SiO 2 is demonstrated and illustrated in Figure 11(d). The bonding temperature is decreased to 120°C, although the fabrication process is extremely complicated and demanding.…”

Section: Nanotwinned Cu and Metal Passivation Layermentioning

confidence: 99%

Recent progress on bumpless Cu/SiO₂ hybrid bonding for 3D heterogeneous integration

Kang

Niu

et al. 2022

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Purpose Bumpless Cu/SiO2 hybrid bonding, which this paper aims to, is a key technology of three-dimensional (3D) high-density integration to promote the integrated circuits industry’s continuous development, which achieves the stacks of chips vertically connected via through-silicon via. Surface-activated bonding (SAB) and thermal-compression bonding (TCB) are used, but both have some shortcomings. The SAB method is overdemanding in the bonding environment, and the TCB method requires a high temperature to remove copper oxide from surfaces, which increases the thermal budget and grossly damages the fine-pitch device. Design/methodology/approach In this review, methods to prevent and remove copper oxidation in the whole bonding process for a lower bonding temperature, such as wet treatment, plasma surface activation, nanotwinned copper and the metal passivation layer, are investigated. Findings The cooperative bonding method combining wet treatment and plasma activation shows outstanding technological superiority without the high cost and additional necessity of copper passivation in manufacture. Cu/SiO2 hybrid bonding has great potential to effectively enhance the integration density in future 3D packaging for artificial intelligence, the internet of things and other high-density chips. Originality/value To achieve heterogeneous bonding at a lower temperature, the SAB method, chemical treatment and the plasma-assisted bonding method (based on TCB) are used, and surface-enhanced measurements such as nanotwinned copper and the metal passivation layer are also applied to prevent surface copper oxide.

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Section: Nanotwinned Cu and Metal Passivation Layermentioning

confidence: 99%

Recent progress on bumpless Cu/SiO₂ hybrid bonding for 3D heterogeneous integration

Kang

Niu

et al. 2022

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“…This VUV treatment caused the surface to become hydrophilic following removal of the surface contaminants(Fig. 1-ii) [17,18]. After VUV treatment, bonding of the LN and quartz combined with the Al 2 O 3 film was performed using a bonding instrument (SB6e, SUSS MicroTec AG).…”

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confidence: 99%

Low-Residual-Stress Amorphous Film for LiTaO<sub>3</sub>/Quartz or LiNbO<sub>3</sub>/Quartz Bonding toward 5G Surface Acoustic Wave Devices

Tezuka

Kuwae

Yamada

et al. 2020

Transactions of The Japan Institute of Electronics Packaging

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LiTaO 3 (LT)/quartz or LiNbO 3 (LN)/quartz bonded surface acoustic wave (SAW) substrates with an amorphous intermediate layer have been proposed for high-frequency communication. Requirements for 5G mobile communication are high-performance SAW substrates with a large SAW velocity, a small temperature coefficient of frequency, and a large electromechanical coupling factor. Reduction of the residual stress of the amorphous intermediate layer is expected to improve the bonding strength and SAW characteristics of the bonded substrate. In this report, a method of low-residualstress amorphous film deposition for LT/quartz or LN/quartz bonding was studied. The residual stresses of amorphous SiO 2 and Al 2 O 3 films deposited by ion beam sputtering, electron cyclotron resonance sputtering, and atomic layer deposition (ALD) were evaluated. The LT substrate with an amorphous Al 2 O 3 film deposited by ALD (ALD-Al 2 O 3) had the minimum warpage of 0.152 µm and residual stress of 127.3 MPa. The ALD-Al 2 O 3 film formed with near-identical thicknesses on both sides of the LT substrate simultaneously, which is likely the source of the low residual stress of the ALD-Al 2 O 3 film. A maximum LN/quartz bonding strength of 3.7 MPa was achieved with the ALD-Al 2 O 3 film. These results indicate that ALD-Al 2 O 3 films are promising materials for LT/quartz or LN/quartz SAW substrates in 5G devices.

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Cu‐to‐Cu and Other Bonding Technologies in Electronic Packaging

2021

Electronic Packaging Science and Technology

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Compensation of Surface Roughness Using an Au Intermediate Layer in a Cu Direct Bonding Process

Cited by 12 publications

References 24 publications

Recent progress on bumpless Cu/SiO₂ hybrid bonding for 3D heterogeneous integration

Recent progress on bumpless Cu/SiO₂ hybrid bonding for 3D heterogeneous integration

Low-Residual-Stress Amorphous Film for LiTaO<sub>3</sub>/Quartz or LiNbO<sub>3</sub>/Quartz Bonding toward 5G Surface Acoustic Wave Devices

Cu‐to‐Cu and Other Bonding Technologies in Electronic Packaging

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Compensation of Surface Roughness Using an Au Intermediate Layer in a Cu Direct Bonding Process

Cited by 12 publications

References 24 publications

Recent progress on bumpless Cu/SiO2 hybrid bonding for 3D heterogeneous integration

Recent progress on bumpless Cu/SiO2 hybrid bonding for 3D heterogeneous integration

Low-Residual-Stress Amorphous Film for LiTaO<sub>3</sub>/Quartz or LiNbO<sub>3</sub>/Quartz Bonding toward 5G Surface Acoustic Wave Devices

Cu‐to‐Cu and Other Bonding Technologies in Electronic Packaging

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Recent progress on bumpless Cu/SiO₂ hybrid bonding for 3D heterogeneous integration

Recent progress on bumpless Cu/SiO₂ hybrid bonding for 3D heterogeneous integration