Single Crystal Plasticity Finite Element Analysis of Cu6Sn5 Intermetallic

Current trend in miniaturization of microelectronic devices is the motivating factor for size reduction of joints and interconnects. The electronic industry is expecting to reduce the scale of interconnects in the next generations microelectronic devices. Mechanical behavior of these joints will significantly be different from traditional solder joints due to the effects such as geometrical and microstructural constraints, anisotropy caused by the reduction in a number of grains, and the presence of brittle intermetallics (IMCs). Mechanical experiments at this scale are very challenging. This study was focused on investigating the effect of different volume fraction of IMCs on the shear behavior of micro-scale solder joints with a 50µm stand-off height. A single lap-shear specimen was designed to conduct the study. Two Copper (Cu) substrates were soldered together with Sn-3.5Ag solder foil and a thickness of 50µm was achieved. The soldering temperature of 260°C and soldering time of 10, 30 and 60 minutes were utilized to achieve approximately 40%, 60% and 80% IMCs of total joint thickness. The experiments were conducted using a micro-tensile tester which is integrated with an optical microscope for monitoring and observing deformation in the testing materials. To investigate the local shear strain behavior, an optical technique along with a developed image processing computer program was used. The single lap-shear tests were conducted with the shear strain rate of 0.015s -1 and 0.15s -1 to observe

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“…This is true for both shear strain rate cases. Shear stiffness of IMCs are higher than that of bulk solder [32][33][34].…”

Section: Shear Stress-strain Properties and Effect Of Imc Thicknessmentioning

confidence: 89%

Local shear stress-strain response of Sn-3.5Ag/Cu solder joint with high fraction of intermetallic compounds: Experimental analysis

Choudhury

Ladani

2016

Journal of Alloys and Compounds

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“…The HCP crystal of η-Cu 6 Sn 5 consists of three slip modes -(i) basal (slip system {0001} <1120>), (ii) prismatic (slip system {1010} <1120> ) ; and <a> pyramidal (slip system {1011} <1120>) , and these modes provide deformation only to <a> direction [12]. In addition to this, the deformation can can occur via combined <c+a> pyramidal slips (slip systems {1011} <1123> and {1022} <1123> ) and deformation twinning.…”

Section: Crystal Plasticity Finite Element Simulationmentioning

confidence: 99%

Crystal structure informed mesoscale deformation model for HCP Cu₆Sn₅ intermetallic compound

Kunwar

Hektor³

2022

2022 23rd International Conference on Electronic Packaging Technology (ICEPT)

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In the electronic packaging and energy storage sectors, the study of Cu6Sn5 intermetallic compound (IMC) is getting more attention. At temperatures above 186 • C, this IMC exists in a hexagonal closed packed (HCP) crystalline structure. Crystal plasticity finite element simulations are performed on Cu6Sn5 IMC by taking the information about its lattice parameters and direction dependent elastic properties. Three types of models corresponding to deformations in basal, prismatic and pyramidal modes are developed. With the same type of loading in the elastic regime and boundary conditions, the results of the computations reveal the differences in displacement magnitudes among the three model types.

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“…Depending on the materials involved in the joining process, the evolution of the microstructures near the interface could be quite complex. For example, the interface generated in the joining process for aluminum or copper generally contains a graded microstructure with a certain amount of intermetallic phases, such as Al 7 Fe 2 Si [ 1 ], Cu 6 Sn 5 and Cu 3 Sn [ 2 ], and Al 4 Cu 9 and Al 2 Cu [ 3 ], near the interfaces which are much stiffer and stronger than the base material. However, the bonding strength of the interfaces between the pure metal and these intermetallic compounds is often lower than the strength of the base materials or compounds.…”

Section: Introductionmentioning

confidence: 99%

“…Within the context of two-phase or multi-phase material systems, the atomic structure-based approach has been successfully invoked to study the evolution of interface characteristics, such as interface thickness and strength, and correlate the interface characteristics with the processing parameters, such as pressure and temperature that are used in the processing of such materials. Accurate mesoscale models have been implemented in analyzing the mechanical performance of CuSn [ 2 ] and fine-grained high-strength steels [ 19 ]. With the newly developed interaction potential for MD methods, the strengths of binary and ternary systems, such as Al–Cu [ 20 , 21 ], Cu–Zr [ 22 ], Ti–V–N [ 23 ], Cr–Fe [ 24 ], and high entropy alloy systems [ 25 , 26 ] have been studied as well.…”

Section: Introductionmentioning

confidence: 99%

On the Evolution of Nano-Structures at the Al–Cu Interface and the Influence of Annealing Temperature on the Interfacial Strength

Wang

Cheng²,

Zhang³

et al. 2022

Nanomaterials

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Molecular dynamics (MD) simulations are invoked to simulate the diffusion process and microstructural evolution at the solid–liquid, cast-rolled Al–Cu interfaces. K-Means clustering algorithm is used to identify the formation and composition of two types of nanostructural features in the Al-rich and Cu-rich regions of the interface (i.e., the intermetallic Al2Cu near the Al-rich interface and the intermetallic Al4Cu9 near the Cu-rich interface). MD simulations are also used to assess the effects of annealing temperature on the evolution of the compositionally graded microstructural features at the Al–Cu interfaces and to characterize the mechanical strength of the Al–Cu interfaces. It is found that the failure of the Al–Cu interface takes place at the Al-rich side of the interface (Al2Cu–Al) which is mechanically weaker than the Cu-rich side of the interface (Cu–Al4Cu9), which is also verified by the nanoindentation studies of the interfaces. Centrosymmetry parameter analyses and dislocation analyses are used to understand the microstructural features that influence deformation behavior leading to the failure of the Al–Cu interfaces. Increasing the annealing temperature reduces the stacking fault density at the Al–Cu interface, suppresses the generation of nanovoids which are precursors for the initiation of fracture at the Al-rich interface, and increases the strength of the interface.

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Single Crystal Plasticity Finite Element Analysis of Cu6Sn5 Intermetallic

Cited by 13 publications

References 51 publications

Local shear stress-strain response of Sn-3.5Ag/Cu solder joint with high fraction of intermetallic compounds: Experimental analysis

Local shear stress-strain response of Sn-3.5Ag/Cu solder joint with high fraction of intermetallic compounds: Experimental analysis

Crystal structure informed mesoscale deformation model for HCP Cu₆Sn₅ intermetallic compound

On the Evolution of Nano-Structures at the Al–Cu Interface and the Influence of Annealing Temperature on the Interfacial Strength

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Single Crystal Plasticity Finite Element Analysis of Cu6Sn5 Intermetallic

Cited by 13 publications

References 51 publications

Local shear stress-strain response of Sn-3.5Ag/Cu solder joint with high fraction of intermetallic compounds: Experimental analysis

Local shear stress-strain response of Sn-3.5Ag/Cu solder joint with high fraction of intermetallic compounds: Experimental analysis

Crystal structure informed mesoscale deformation model for HCP Cu6Sn5 intermetallic compound

On the Evolution of Nano-Structures at the Al–Cu Interface and the Influence of Annealing Temperature on the Interfacial Strength

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Crystal structure informed mesoscale deformation model for HCP Cu₆Sn₅ intermetallic compound