Copper Direct-Bonding Characterization and Its Interests for 3D Integration

Gueguen, Pierric; Cioccio, L. Di; Gergaud, P.; Rivoire, M.; Scevola, Daniel; Zussy, M.; Charvet, Anne-Marie; Bally, Laurent; Lafond, D.; Clavelier, L.

doi:10.1149/1.3187271

Cited by 66 publications

(34 citation statements)

References 6 publications

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“…Thanks to this specific surface preparation, surfaces can adhere to each other at room temperature (RT) under atmospheric pressure (CMP-activated bonding). 18 This structure is then submitted to a post-bonding annealing of 1 hour at 400…”

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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“…1b). Copper surface exhibits after these CMP steps a typical highly hydrophilic behavior (water droplet contact angle below 7°) which stays stable during 1 h (Gueguen et al 2009). The bonding is performed under three different atmospheres: at room temperature under cleanroom atmosphere (20 °C and 40 % of relative humidity), under vacuum (surfaces are brought into contact in a bonding chamber pumped down to 10 −3 Pa) and under vacuum after a preannealing step (surfaces are heated to 300 °C, cooled down and brought into contact in a bonding chamber pumped down to 10 −3 Pa).…”

Section: Sample Preparationmentioning

confidence: 99%

“…Since ECD technique is often used in industrial context, most of copper-copper direct bonding studies are performed on copper layers deposited by this technique (Di Cioccio et al 2011;Gueguen et al 2009;Martinez et al 2013). However, some applications could need other copper layer deposition technique such as PVD.…”

Section: Impact Of Copper Layers Deposition Techniquementioning

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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“…Cu-Cu has been bonded at room temperature by direct hydrophilic bonding for electrical interfaces [109][110][111]. Chemical mechanical polishing is conducted to provide the surface of Cu with low roughness and good hydrophilicity.…”

Section: Other Direct Bonding Technologiesmentioning

confidence: 99%

Low-Temperature Bonding for Silicon-Based Micro-Optical Systems

Howlader

Deen

2015

Photonics

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Abstract:Silicon-based integrated systems are actively pursued for sensing and imaging applications. A major challenge to realize highly sensitive systems is the integration of electronic, optical, mechanical and fluidic, all on a common platform. Further, the interface quality between the tiny optoelectronic structures and the substrate for alignment and coupling of the signals significantly impacts the system's performance. These systems also have to be low-cost, densely integrated and compatible with current and future mainstream technologies for electronic-photonic integration. To address these issues, proper selection of the fabrication, integration and assembly technologies is needed. In this paper, wafer level bonding with advanced features such as surface activation and passive alignment for vertical electrical interconnections are identified as candidate technologies to integrate different electronics, optical and photonic components. Surface activated bonding, superior to other assembly methods, enables low-temperature nanoscaled component integration with high alignment accuracy, low electrical loss and high transparency of the interface. These features are preferred for the hybrid integration of silicon-based micro-opto-electronic systems. In future, new materials and assembly technologies may emerge to enhance the performance of these micro systems and reduce their cost. The article is a detailed review of bonding techniques for electronic, optical and photonic components in silicon-based systems.

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Copper Direct-Bonding Characterization and Its Interests for 3D Integration

Cited by 66 publications

References 6 publications

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

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

Kinetics of low temperature direct copper–copper bonding

Low-Temperature Bonding for Silicon-Based Micro-Optical Systems

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