A Metal Bump Bonding Method Using Ag Nanoparticles as Intermediate Layer

Fu, Weixin; Nimura, Masatsugu; Kasahara, Takashi; Mimatsu, Hayata; Okada, Akiko; Shoji, Shuichi; Ishizuka, Shugo; Mizuno, Jun

doi:10.1007/s11664-015-3932-0

Cited by 6 publications

(1 citation statement)

References 17 publications

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“…Ultrathin capping layers are used to protect Cu from oxidation and therefore enable bonding after storage at air conditions. Various materials were investigated for this purpose: Au, Ag, Pd, Al, Co/Au, Ni/Au, Ti (Suga et al, 2017;Fu et al, 2015;Pinnel, 1979). However, noble metal coatings cause additional high costs, whereby other candidates tend to build an oxide layer and thus increase resistivity of the interconnect.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of Cu/Cu bonding using self-assembled monolayer

Lykova

Panchenko

Künzelmann

et al. 2018

SSMT

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Purpose Cu/Cu diffusion bonding is characterised by high electrical and thermal conductivity, as well as the mechanical strength of the interconnects. But despite a number of advantages, Cu oxidises readily upon exposure to air. To break through the adsorbed oxide-layer high temperature and pressure, long bonding time and inert gas atmosphere are required during the bonding process. This paper aims to present the implementation of an organic self-assembled monolayer (SAM) as a temporary protective coating that inhibits Cu oxidation. Design/methodology/approach Information concerning elemental composition of the Cu surface has been yielded by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) spectroscopy. Two types of substrates (electroplated and sputtered Cu) are prepared for thermocompression bonding in two different ways. In the first case, Cu is cleaned with dilute sulphuric acid to remove native copper oxide. In the second case, passivation with SAM followed the cleaning step with dilute sulphuric acid. Shear strength, fracture surface, microstructure of the received Cu/Cu interconnects are investigated after the bonding procedure. Findings The XPS method revealed that SAM can retard Cu from oxidation on air for at least 12 h. SAM passivation on the substrates with sputtered Cu appears to have better quality than on the electroplated ones. This derives from the results of the shear strength tests and scanning electron microscopy (SEM) imaging of Cu/Cu interconnects cross sections. SAM passivation improved the bonding quality of the interconnects with sputtered Cu in comparison to the cleaned samples without passivation. Originality/value The Cu/Cu bonding procedure was optimised by a novel preparation method using SAMs which enables storage and bonding of Si-dies with Cu microbumps at air conditions while remaining a good-quality interconnect. The passivation revealed to be advantageous for the smooth surfaces. SEM and shear strength tests showed improved bonding quality for the passivated bottom dies with sputtered Cu in comparison to the samples without SAM.

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Section: Introductionmentioning

confidence: 99%

Characterisation of Cu/Cu bonding using self-assembled monolayer

Lykova

Panchenko

Künzelmann

et al. 2018

SSMT

View full text Add to dashboard Cite

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Thin‐Film Assisted Laser Transfer and Bonding (TFA‐LTAB) for the Fabrication of Micro‐LED Displays

Lang,

Lin,

Huang

et al. 2024

Adv Elect Materials

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Micro‐Light Emitting Diodes (Micro‐LEDs) are key components in the field of next‐generation display technologies. In the process of making Micro‐LED displays, millions of chips need to be transferred to the driver substrate using mass transfer technology. Conventional transfer techniques, such as stamp transfer, present challenges in terms of processing efficiency and applicability due to the need for pre‐prepared tethered structures and fixed chip pitch. To overcome these limitations, the t hin‐film‐assisted laser transfer and bonding (TFA‐LTAB) technology is proposed. This technique is able to efficiently and accurately transfer Micro‐LEDs from the source substrate to the driver substrate with arbitrary pitch through thin‐film assistance, and electrically connects the chips through flip‐chip bonding technology, which significantly improves the efficiency and reliability of the transfer and joining. The TFA‐LTAB method proposed in this study integrates laser transfer and flip‐chip bonding techniques. Through the TFA‐LTAB process, these Micro‐LEDs cultured on sapphire substrates are precisely assembled onto transparent low‐temperature polycrystalline silicon thin‐film transistors (LTPS‐TFTs). The method successfully achieved mass transfer and bonding of Micro‐LEDs with a size of 30 × 15 µm2 at low temperature (180 °C) and low pressure (0.08 MPa).

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Low Temperature Flip Chip Bonding Using Squeegee-Embedded Au Nanoporous Bump Activated by VUV/O3 Treatment

Kaneda

Okada

et al. 2018

Journal of Elec Materi

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A Metal Bump Bonding Method Using Ag Nanoparticles as Intermediate Layer

Cited by 6 publications

References 17 publications

Characterisation of Cu/Cu bonding using self-assembled monolayer

Characterisation of Cu/Cu bonding using self-assembled monolayer

Thin‐Film Assisted Laser Transfer and Bonding (TFA‐LTAB) for the Fabrication of Micro‐LED Displays

Low Temperature Flip Chip Bonding Using Squeegee-Embedded Au Nanoporous Bump Activated by VUV/O3 Treatment

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