Reliability of hybrid bond interconnects

Gambino, Jeff; Thomas, Kyle; Müller, R.; Truong, Hoa D.; Defibaugh, DC; Price, D.; Goshima, Keiko; Hirano, Takuichi; Watanabe, Yukihiko; Breen, Mark; Oldham, N. C.

doi:10.1109/iitc-amc.2017.7968972

Cited by 10 publications

(4 citation statements)

References 10 publications

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“…In addition to TSVs, hybrid bonding techniques that involve both Cu bonding and oxide bonding have also been developed for 3DIC applications. Typically, oxide-oxide bonding occurs at room temperature before the temperature is raised to around 300 • C for Cu-Cu bonding [12][13][14][15][16]. The requirement to elevate the temperature is attributed to the higher coefficient of thermal expansion (CTE) of Cu compared to the surrounding SiO 2 [17].…”

Section: Introductionmentioning

confidence: 99%

“…The success of the hybrid bonding process relies on the final chemical mechanical polishing (CMP) stage of the copper [18,19]. During this stage, it is essential to achieve a flat oxide surface while ensuring that the copper is slightly recessed from the oxide Materials 2024, 17, 2150 2 of 10 surface [12][13][14]. The degree of "Cu recess" required depends on several factors, including the bonding temperature [20,21], expected service temperature, and the depth of TSV (Cu film thickness).…”

Section: Introductionmentioning

confidence: 99%

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Effect of Cu Film Thickness on Cu Bonding Quality and Bonding Mechanism

Lu,

Hsu,

Hsu

et al. 2024

Materials

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In the hybrid bonding process, the final stage of chemical mechanical polishing plays a critical role. It is essential to ensure that the copper surface is recessed slightly from the oxide surface. However, this recess can lead to the occurrence of interfacial voids between the bonded copper interfaces. To examine the effects of copper film thickness on bonding quality and bonding mechanisms in this study, artificial voids were intentionally introduced at the bonded interfaces at temperatures of 250 °C and 300 °C. The results revealed that as the thickness of the copper film increases, there is an increase in the bonding fraction and a decrease in the void fraction. The variations in void height with different copper film thicknesses were influenced by the bonding mechanism and bonding fraction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Cu Film Thickness on Cu Bonding Quality and Bonding Mechanism

Lu,

Hsu,

Hsu

et al. 2024

Materials

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“…The recess of Cu pads, which is typically a few nanometers [16], should be smaller than their expansions to ensure proper contact during annealing. This allows for oxide-oxide bonding to take place at room temperature before raising the temperature to approximately 250-300 • C for Cu-Cu bonding [17][18][19][20]. The requirement to elevate the temperature is attributed to the higher coefficient of thermal expansion (CTE) of Cu compared to the surrounding SiO 2 [21].…”

Section: Introductionmentioning

confidence: 99%

Effect of Compressive Stress on Copper Bonding Quality and Bonding Mechanisms in Advanced Packaging

Lu,

Lee,

2024

Materials

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The thermal expansion behavior of Cu plays a critical role in the bonding mechanism of Cu/SiO2 hybrid joints. In this study, artificial voids, which were observed to evolve using a focused ion beam, were introduced at the bonded interfaces to investigate the influence of compressive stress on bonding quality and mechanisms at elevated temperatures of 250 °C and 300 °C. The evolution of interfacial voids serves as a key indicator for assessing bonding quality. We quantified the bonding fraction and void fraction to characterize the bonding interface and found a notable increase in the bonding fraction and a corresponding decrease in the void fraction with increasing compressive stress levels. This is primarily attributed to the Cu film exhibiting greater creep/elastic deformation under higher compressive stress conditions. Furthermore, these experimental findings are supported by the surface diffusion creep model. Therefore, our study confirms that compressive stress affects the Cu–Cu bonding interface, emphasizing the need to consider the depth of Cu joints during process design.

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“…Currently, chips and wafers with different functions are manufactured separately and vertically stacked via hybrid bonding processes, which offer a promising solution for three-dimensional (3D) integration to continue Moore's law [1][2][3]. The wafer-level hybrid bonding of Cu and silicon oxides has already been applied in the mass-production stacking of back-illuminated CMOS image sensors (BI-CIS) [4].…”

Section: Introductionmentioning

confidence: 99%

High-Bonding-Strength Polyimide Films Achieved via Thermal Management and Surface Activation

Tran

Kuo

et al. 2023

Nanomaterials

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In this study, thermal and argon (Ar) plasma/wetting treatments were combined to enhance the bonding strength of polyimide (PI) films. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) was used to analyze the changes in the PI imidization degrees. The contact angles of the PI films were also measured. The results show that the contact angles of the fully cured PI films markedly decreased from 78.54° to 26.05° after the Ar plasma treatments. X-ray photoelectron spectroscopy (XPS) analysis was also conducted on the PI surfaces. We found that the intensities of the C-OH and C-N-H bonds increased from 0% to 13% and 29% to 57%, respectively, after Ar plasma activation. Such increases in the C-OH and C-N-H intensities could be attributed to the generation of dangling bonds and the breakage of the imide ring or polymer long chains. Shear tests were also conducted to characterize the bonding strength of the PI films, which, after being treated with the appropriate parameters of temperature, plasma power, and wetting droplets, was found to be excellent at greater than 35.3 MPa.

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Reliability of hybrid bond interconnects

Cited by 10 publications

References 10 publications

Effect of Cu Film Thickness on Cu Bonding Quality and Bonding Mechanism

Effect of Cu Film Thickness on Cu Bonding Quality and Bonding Mechanism

Effect of Compressive Stress on Copper Bonding Quality and Bonding Mechanisms in Advanced Packaging

High-Bonding-Strength Polyimide Films Achieved via Thermal Management and Surface Activation

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