Cu-Sn Intermetallic Compound Joints for High-Temperature Power Electronics Applications

Lee, Byung-Suk; Yoon, Jeong‐Won

doi:10.1007/s11664-017-5792-2

Cited by 43 publications

(15 citation statements)

References 26 publications

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“…Moreover, the Cu6Sn5 grains that were reflowed 1 time were milled to obtain a fine powder and studied by X-ray diffraction (XRD, D8 Advance, Bruker Inc., Karlsruhe, Germany, Cu-Kα radiation) and differential scanning calorimetry (DSC, 214 Polyma, NETZSCH Inc., Selb, Germany). It should be noted that the XRD measurement was conducted at a cooling rate of 20 °C/min from 220 °C to 20 °C, and that the data at each selected Because of the thermal mismatch between Cu 6 Sn 5 and Si during multiple reflow processes, cyclic strains are considered to be the dominant cause of damage to IMC interconnections in 3D packages [9,10]. However, Cu 6 Sn 5 has at least two phases in the solid state, and its η phase (P6 3 /mmc) can thermodynamically transform to the η phase (C2/c) with a volume expansion of 2.2% below 186 • C [11,12].…”

Section: Methodsmentioning

confidence: 99%

Damage Mechanism of Cu6Sn5 Intermetallics Due to Cyclic Polymorphic Transitions

et al. 2019

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The formation of high-melting-point Cu6Sn5 interconnections is crucial to overcome the collapse of Sn-based micro-bumps and to produce reliable intermetallic interconnections in three-dimensional (3D) packages. However, because of multiple reflows in 3D package manufacturing, Cu6Sn5 interconnections will experience cyclic polymorphic transitions in the solid state. The repeated and abrupt changes in the Cu6Sn5 lattice due to the cyclic polymorphic transitions can cause extreme strain oscillations, producing damage at the surface and in the interior of the Cu6Sn5 matrix. Moreover, because of the polymorphic transition-induced grain splitting and superstructure phase formation, the reliability of Cu6Sn5 interconnections will thus face great challenges in 3D packages. In addition, the Cu6Sn5 polymorphic transition is structure-dependent, and the η′↔η polymorphic transition will occur at the surface while the η′↔ηs↔η polymorphic transition will occur in the deep matrix. This study can provide in-depth understanding of the structural evolution and damage mechanism of Cu6Sn5 interconnections in real 3D package manufacturing.

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Section: Methodsmentioning

confidence: 99%

Damage Mechanism of Cu6Sn5 Intermetallics Due to Cyclic Polymorphic Transitions

et al. 2019

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“…The IMC was treated as the Cu 6 Sn 5 in the simulations. Although, Cu 3 Sn generally exhibits superior properties: higher strength, higher elongation, and lower elastic modulus compared to Cu 6 Sn 5 [18,42], the transformation of the IMCs and formation of the submicron voids needs to be explained, which will be discussed in future work. The results of FE analysis in this study suggested the stable mechanical properties of the IMC-based composites at high temperature, which is a significant advantage of these composites over the solder-based ones.…”

Section: Reliability Of Tlps Joints During Thermal Cyclingmentioning

confidence: 99%

“…Once the solder is completely transformed into a Cu-Sn intermetallic compound (IMC) during the reflow process, a bonding layer with high re-melting temperature can be obtained. Several studies have demonstrated the high bondability and high-temperature resistance of the Cu-Sn system [18][19][20][21] and similar Ni-Sn and Ag-Sn systems [22][23][24]. These studies focused on the realization of "dense" IMC bonding layer and high joint strength using a low-temperature and short-time bonding process based on interdiffusion control between the metal particles.…”

Section: Introductionmentioning

confidence: 99%

Deformation Behavior of Transient Liquid-Phase Sintered Cu-Solder-Resin Microstructure for Die-Attach

et al. 2019

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We have proposed a low-temperature bonding technology utilizing the sintering of Cu particles with transient liquid-phase of Sn-based solder, called transient liquid-phase sintering (TLPS), as a die-attach solution for high-temperature power modules. A copper-intermetallic compound-resin (Cu-IMC-resin) microstructure, which consists of Cu particles connected with Cu–Sn intermetallic compounds (IMCs) partially filled with polyimide resin, is obtained by the pressureless TLPS process at 250 °C for 1 min using a novel Cu-solder-resin composite as the bonding material in a nitrogen atmosphere. Macro- and micro-deformation properties of the unique microstructure of the TLPS Cu-IMC-resin are evaluated by finite element analysis using a three-dimensional image reconstruction model. The macroscopic computational uniaxial tensile tests of the Cu-IMC-resin model reveal that the utilization of the IMCs and the addition of the easily-deformable resin facilitates the temperature-stability and low-stiffness of the mechanical properties. The microstructure exhibits a significantly low homogenized Young’s modulus (11 GPa). Microscopic investigations show that the local stresses are broadly distributed on the IMC regions under uniaxial macroscopic tensile displacement, indicating highly reliable performance of the joint within a specific macroscopic strain condition. Numerical and experimental investigations demonstrate the excellent thermal cyclic reliability of die-attached joints between silicon carbide chips and directly bonded copper substrate.

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“…Because of the thermal mismatch between Cu6Sn5 and Si during multiple reflow processes, cyclic strains are considered to be the dominant cause of damage to IMC interconnections in 3D packages [9,10]. However, Cu6Sn5 has at least two phases in the solid state, and its η phase (P63/mmc) can 2 of 9 thermodynamically transform to the η′ phase (C2/c) with a volume expansion of 2.2% below 186 °C [11,12].…”

Section: Introductionmentioning

confidence: 99%

Damage Mechanism of Cu<sub>6</sub>Sn<sub>5</sub> Intermetallics Due to Cyclic Polymorphic Transitions

Zhang¹,

Wei²,

Cao

et al. 2019

Preprint

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The formation of high-melting-point Cu6Sn5 interconnections is crucial to overcome the collapse of Sn-based micro-bumps and produce reliable intermetallic interconnections in three-dimensional (3D) package. However, because of the multiple reflows in 3D package manufacturing, Cu6Sn5 interconnections will experience the cyclic polymorphic transitions in the solid state. The repeated and abrupt change in the Cu6Sn5 lattice due to the cyclic polymorphic transitions can cause extreme strain oscillations, producing damages at the surface and in the interior of the Cu6Sn5 matrix. Moreover, because of the polymorphic-transition-induced grain splitting and superstructure phase formation, the reliability of Cu6Sn5 interconnections will thus face great challenges in 3D package. In addition, the Cu6Sn5 polymorphic transition is structure-dependent, and the η′↔η polymorphic transition will occur at the surface while the η′↔ηs↔η polymorphic transition will occur in the deep matrix. Our results can provide in-depth understandings of structural evolution and damage mechanism of Cu6Sn5 interconnections in real 3D package manufacturing.

show abstract

Cu-Sn Intermetallic Compound Joints for High-Temperature Power Electronics Applications

Cited by 43 publications

References 26 publications

Damage Mechanism of Cu6Sn5 Intermetallics Due to Cyclic Polymorphic Transitions

Damage Mechanism of Cu6Sn5 Intermetallics Due to Cyclic Polymorphic Transitions

Deformation Behavior of Transient Liquid-Phase Sintered Cu-Solder-Resin Microstructure for Die-Attach

Damage Mechanism of Cu<sub>6</sub>Sn<sub>5</sub> Intermetallics Due to Cyclic Polymorphic Transitions

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