Modified diffusion bond process for chemical mechanical polishing (CMP)-Cu at 150&amp;#x00B0;C in ambient air

Shigetou, Akitsu; Suga, Tadatomo

doi:10.1109/ectc.2009.5074042

Cited by 10 publications

(3 citation statements)

References 9 publications

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“…surface topology degradation). 10,19 Thus, structures involving top gold (Au) thin films have been added to this study. Indeed, gold has been taken into account as an oxide free metal exhibiting mechanical properties (in terms of Young modulus and ductility) close to copper properties.…”

Section: Sample Preparationmentioning

confidence: 99%

Voiding Phenomena in Copper-Copper Bonded Structures: Role of Creep

Gondcharton

Imbert

Benaissa

et al. 2015

ECS J. Solid State Sci. Technol.

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In 3D integration industrial context, copper is widely favored over others metals as a bonding material for its exceptional electrical and mechanical properties. It has been already reported that directly bonded structures involving copper layers exhibit typical voids that drastically abound beyond 300 • C. In order to have a better understanding of the voiding process, we specifically designed structures involving materials and surfaces exhibiting different properties. These stacks underwent different bonding processes which mainly differ in the mechanical applied load. For each variation in this study the total volume of voids was estimated throughout a strict protocol. Thus, we demonstrate that voiding phenomena is related to a stress driven vacancy diffusion very comparable to standard metallurgical creep mechanisms. Regarding the origin of the vacancies, among all the possible options, two predominant sources have been identified. Better understanding of these physical phenomena should enable the achievement of advanced wafer assemblies exhibiting much higher reliability and quality.

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Section: Sample Preparationmentioning

confidence: 99%

Voiding Phenomena in Copper-Copper Bonded Structures: Role of Creep

Gondcharton

Imbert

Benaissa

et al. 2015

ECS J. Solid State Sci. Technol.

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“…In the previous studies, it is indicated that the hydrophilic bonding of Cu requires the adsorbed water on the Cu oxides (9,10). The adsorbed water forms hydrogen bonds and intermolecular bonds at the bonding interface.…”

Section: Resultsmentioning

confidence: 99%

Hydrophilic Bonding of SiO₂/SiO₂ and Cu/Cu using Sequential Plasma Activation

Takeuchi,

Ninomiya,

Kubota

et al. 2023

ECS Trans.

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Hybrid bonding is an indispensable technique for the 3D integration of electronic systems. Cu-to-Cu interconnections and SiO2-to-SiO2 dielectric layers should be bonded simultaneously in the wafer-to-wafer bonding process. In this study, sequential plasma activation (SPA) including O2 plasma, N2 plasma, and N radical is investigated for low-temperature bonding of Cu and TEOS SiO2 at 200°C. The SPA bonding improves the bond strength to more than 1 J/m2 compared to the conventional single gas plasma activation bonding. The surface analysis indicates that SPA forms oxynitrides on TEOS SiO2 surface and Cu oxide with adsorbed water on the Cu surface, facilitating the bonding interface formation. The presented technique will contribute to the hybrid bonding applications at lower temperatures.

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“…Since copper is widely used in CMOS interconnects for its low electrical resistivity and high electromigration resistance (Ryan et al 1995), direct copper-copper bonding at low temperature is a promising option for implementation of three-dimension integrated circuits (3D-IC) or micro electrical mechanical systems (MEMS). Various bonding techniques exist to join copper surfaces in the temperature range below 400 °C involving for example a uniaxial compressive force (Chen et al 2005), a surface activation by ion bombardment (Shigetou and Suga 2009), a surface passivation by an organic monolayer (Tan et al 2009) or chemical mechanical polishing (CMP) steps (Di Cioccio et al 2011). More specifically, the direct bonding technique involving CMP surface activation consists to put into contact two mirror-polished wafers which are held together by attractive forces at room temperature (RT) without any additional materials.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of low temperature direct copper–copper bonding

et al. 2015

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International audienceWafer level metal bonding involving copper layers is a key technology for three-dimensional integration. An appropriate surface activation can be performed in order to obtain room temperature direct bonding with bonding strength to be compatible with microelectronic device integration. In this paper, we focus on bonding strengthening mechanisms in the low temperature range from 20 to 100 A degrees C. In order to improve the bonding interface closure, several process parameters are studied: water amount available when surfaces are brought into contact and copper layers deposition technique have been identified to be predominant in this low temperature range. Based on metal oxidation theory, several mechanisms are proposed and some calculations on this bonding strengthening are performed. For the first time, activation energies of this phenomenon are obtained for copper layers deposited by different method in the specific environment of the bonding interface. This study gives guidelines and recommendations for the integration of this metal bonding technique at low temperature

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Modified diffusion bond process for chemical mechanical polishing (CMP)-Cu at 150°C in ambient air

Cited by 10 publications

References 9 publications

Voiding Phenomena in Copper-Copper Bonded Structures: Role of Creep

Voiding Phenomena in Copper-Copper Bonded Structures: Role of Creep

Hydrophilic Bonding of SiO₂/SiO₂ and Cu/Cu using Sequential Plasma Activation

Kinetics of low temperature direct copper–copper bonding

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Modified diffusion bond process for chemical mechanical polishing (CMP)-Cu at 150&#x00B0;C in ambient air

Cited by 10 publications

References 9 publications

Voiding Phenomena in Copper-Copper Bonded Structures: Role of Creep

Voiding Phenomena in Copper-Copper Bonded Structures: Role of Creep

Hydrophilic Bonding of SiO2/SiO2 and Cu/Cu using Sequential Plasma Activation

Kinetics of low temperature direct copper–copper bonding

Contact Info

Product

Resources

About

Modified diffusion bond process for chemical mechanical polishing (CMP)-Cu at 150°C in ambient air

Hydrophilic Bonding of SiO₂/SiO₂ and Cu/Cu using Sequential Plasma Activation