Morphology Of Cu6Sn5 Research Articles

Influence of carbon nanotubes on the morphology of Cu6Sn5 in Cu/(Sn–Ag–Cu) solder joints

This study delves into the intricate interaction between multi-walled carbon nanotubes (MWCNTs) and the Sn–Ag–Cu solder system, highlighting its relevance in lead-free soldering applications. Reflow and isothermal aging induce the formation of intermetallic layers at the joint interface, including Cu6Sn5, Cu3Sn, and irregularly shaped Ag3Sn particles. The addition of MWCNTs leads to the flattening of Cu6Sn5 grains, restraining their growth and potentially improving mechanical strength. Notably, MWCNTs exhibit a relatively high affinity with Ag3Sn. Grain size distribution analysis indicates that MWCNTs reduce particle size, effectively suppressing intermetallic compound growth. Over time, grain size increases due to simultaneous coarsening and growth during isothermal aging. In the growth kinetics analysis of intermetallic compounds in SAC305-MWCNTs solder joints, stable behavior is observed for Cu3Sn growth, driven by solid-state diffusion between Cu6Sn5 and Cu. In contrast, Cu6Sn5 exhibits significant variations in growth behavior with temperature changes. Furthermore, the evaluation of activation enthalpy for Cu3Sn growth in the Cu/(SAC305-MWCNTs) and Cu/SAC305 diffusion couples reveals similar n and k values of the power function for the layer growth, indicating a comparable rate-controlling process for Cu3Sn growth. The presence of MWCNTs in the solder does not significantly influence the rate-controlling process or activation enthalpy for Cu3Sn growth, contrasting with the observed effects on Cu6Sn5 growth. This study provides valuable insights into the interactions within the SAC305-MWCNTs solder system, offering significant implications for lead-free soldering applications.

Study on Cu6Sn5 morphology and grain orientation transition at the interface of (111) nt-Cu and liquid Sn

Nanotwinned copper (nt-Cu) is considered to be very desirable choice for a pad material in system-in-package (SiP) devices due to its excellent anti-electromigration and anti-element migration properties. However, complex diffusion reactions exist between nt-Cu and Sn-based solder. Especially, morphology and grain orientation transition of intermetallic compounds (IMCs) appeared after multiple reflow processes. There is a lack of deep understanding of the mechanisms of the above processes. In this paper, nt-Cu was obtained by direct-current electroplating as a pad material with (111) preferred orientation, and a two-step soldering process including dip-soldering and reflow was designed to investigate the influence of temperature on IMCs morphology. The thermodynamic and molecular dynamic simulations were used to analyze the evolution mechanism of the above process. During dip-soldering process, the size of the atomic clusters was influenced by temperature, resulting in the formation of scalloped and roof-like Cu6Sn5 grains at the solidification stage. The roof-like Cu6Sn5 solder joints had a 10.7% higher shear strength and a 15% slower growth rate compared with the scalloped Cu6Sn5 solder joints. Furthermore, roof-like Cu6Sn5 had a (-12-10) preferred orientation. However, the orientation of Cu6Sn5 grains transitioned to (0001) during reflow process. Molecular dynamics simulations showed that (0001)-oriented Cu6Sn5 grains had the lowest surface energy. The decrease in surface energy was the driving force for the grain orientation transition. This work shows that the influence of temperature on interfacial IMCs could be used to form nt-Cu/Sn/nt-Cu micro-solder joints with controlled Cu6Sn5 morphology and orientation, which can significantly enhance their shear strength and reliability.

Study on interfacial reaction behavior of Sn[sbnd]Ag based lead-free solder with (111) single crystal copper substrate

The morphology and crystal orientation of intermetallic compounds formed by the reaction between SAC305 solder/(111) and SABI333 solder/(111) single crystal copper substrate were investigated. The morphology of Cu6Sn5 at the interface of SAC305 solder/(111) single crystal copper substrate changes from scallop to prismatic with the increase of reflow time. The Cu6Sn5 grains grow parallel to the horizontal direction of the Cu substrate and grow along the vertical direction, and there is an Angle of 60° between different Cu6Sn5 crystals. The calculated b ~ t0.23 relation satisfies the growth kinetics of prismatic Cu6Sn5. In addition, the morphology of Cu6(Sn, In)5 at the interface of SABI333 solder/(111) single crystal copper substrate is between scallop-type and prismatic-type. Cu6(Sn, In)5 grains grow at a certain angle with a single crystal copper substrate due to the addition of In element. Furthermore, it is considered that the deflection mechanism of Cu6(Sn, In)5 grains is controlled by the length and strength of inter-atomic bonds within the grains after the In atom substitution reaction.

Effect of different Cu6Sn5 morphology on the tribological properties of Babbitt alloy

PurposeThis paper aims to study different morphology Cu6Sn5 effect on Babbitt alloy tribological properties.Design/methodology/approachDifferent morphology Cu6Sn5 of Babbitt was conducted by different cooling modes. Bare Babbitt was marked by Babbitt-0, Babbitt modified by first cooling mode (marked by Babbitt-1) and Babbitt modified by second cooling mode (marked by Babbitt-2). The microstructure and microhardness of specimens were tested. Then, tribological properties of Babbitt-0, Babbitt-1 and Babbitt-2 were performed by reciprocating mode under lubricated condition.FindingsThe results showed that shape Cu6Sn5 of Babbitt was changed from mixed needle and star-like shape to short rod-like or granular shape. The microhardness of Babbitt-1 was highest than that of Babbitt-0 and Babbitt-2. Compared with Babbitt-0 and Babbitt-2, tribological properties of Babbitt-1 were better under lubricated condition due to short rod-like and sparse distribution of Cu6Sn5. Moreover, the simulation result of strain and stress of Babbitt-1 was lowest than that of Babbitt-0 and Babbitt-2.Originality/valueDifferent morphology (shape and distributed) of Cu6Sn5 was obtained by different cooling modes. Modulated different forms of Cu6Sn5 around SnSb was beneficial to improve Babbitt alloy tribological properties.

New phenomenon: Cellular boundary during the isothermal stage in the Sn-3Ag/(0 0 1)Cu and Sn-3.5Ag/(0 0 1)Cu joint

The Cu6Sn5 intermetallic, which commonly forms at the solder interconnects, is a critical component contributing to the reliability of solder joints. In this paper, the growth behavior during the isothermal stage of Cu6Sn5 grains in the Sn-xAg/(001)Cu (x = 0, 3, 3.5) joint was investigated. A new phenomenon, the Cu6Sn5 with cellular boundary, is found in the isothermal stage of Sn-3Ag/(001)Cu and Sn-3.5Ag/(001)Cu joint, but not found in the Sn/(001)Cu joint. The result suggests that the Ag3Sn play an important role in the formation of the cellular boundary. High-pressure air blowing was used to uncover the morphology of Cu6Sn5 at the isothermal stage. Scanning electron microscopy and electron backscatter diffraction were employed to characterize the morphology and grain orientation, respectively. The result has a great meaning in understanding the growth of Cu6Sn5 during the isothermal stage and improving the reliability of solder joints.

Bidirectional pulsed current effect on the precipitation behavior of Cu6Sn5: An in situ observation

Cu6Sn5 plays an important role in tin-based babbitt alloys and microelectronic interconnections. This study used the in situ synchrotron X-ray radiography to study the effect of bidirectional pulse currents on the precipitation behavior of Cu6Sn5. The Boltzmann cumulative distribution function was used as a model for fitting the grain density versus temperature, where R2 ≥ 0.995 confirms a good correlation of the model with experimental data. The results show that bidirectional pulsed currents can effectively control the initial nucleation temperature, maximum nucleation rate, and final grain density. In addition, bidirectional pulsed current affects the growth morphology of Cu6Sn5. The thorn-like growth morphology is facilitated with the current density increasing from 0 A/cm2 to 50 A/cm2, but it is suppressed with the current density increasing from 50 A/cm2 to 200 A/cm2. This study improves the fundamental understanding of nucleation and growth behavior of Cu6Sn5 under bidirectional pulsed current and provides guidance for controlling the size and morphology of Cu6Sn5.

Effect of transient current bonding on interfacial reaction in Ag-coated graphene Sn–Ag–Cu composite solder joints

To address the problem of floating and aggregation of Ag–GNSs in the molten pool during the traditional reflow soldering process, Cu/SAC/Ag–GNSs/Cu sandwich joints were prepared under an applied current density (1.0×104 A/cm2) for a few hundred milliseconds to produce Ag-coated graphene-reinforced Sn–Ag–Cu (SAC/Ag– GNSs) solder joints. The experimental results showed that Ag–GNSs were homogenously dispersed in the solder joints, providing more Cu6Sn5 grain nucleation sites, which refined these grains and reduced the thickness difference at the anode and cathode. In addition, the Cu6Sn5 morphology changed from rod-like to plate-shaped because of the uniform distribution of Ag–GNSs and constitutional supercooling. The significantly increased shear strength of the transient current bonding and the change in the fracture mechanism were due to the uniformly distributed Ag–GNSs and the microstructural changes.

Significant effect of orientation on Cu6Sn5 coarsening behavior in isothermal aging process

Intermetallic compound (IMC) formed on (001) and (111) Cu single crystal has strong orientation and texture characteristics. The special interface morphology and uniform orientation provide a direction for the regulation of IMC growth behavior. In this study, the significant effect of orientation on Cu6Sn5 growth behavior in isothermal aging process was investigated. Synchrotron radiation technology and high pressure air blowing methods were employed to obtain the growth kinetics and the morphology of Cu6Sn5 during the heat preservation stage. The results indicate that scallop-like Cu6Sn5 grains were formed in heat preservation stage. These grains exhibited an abnormal coarsening behavior that their average diameter at a high temperature of 300 °C was smaller than that at a low temperature of 250 °C after aging for 30 min. Besides, the growth orientation and kinetic controlling factor of these interfacial Cu6Sn5 also changed with the increase of reaction time, which was closely related to the appearance of the abnormal coarsening phenomenon. These results are significant and meaningful to the electronic packaging industry.

Low-Temperature Cu-Cu Bonding Process Based on the Sn-Cu Multilayer and Self-Propagating Reaction Joining

Transient liquid phase bonding can be realized at a relatively low temperature through building an intermetallic interconnection. A self-propagating reaction joint can achieve a low temperature bond by confining the heat at the bonding interface and reduce the thermal effect on other components. In this work, a Sn-Cu alternating multilayer was combined with an Al-Ni self-propagating reaction joint to develop a highly efficient low-temperature Cu-Cu hybrid bonding process. The Sn-Cu alternating multilayer was directly prepared on the Cu substrates by an alternating electroplating process. The Al-Ni multilayer film was sandwiched between two Cu substrates under a pressure of 5 MPa and ignited with a 15-V spark at room temperature. Cu-Cu bonds with three different Sn/Cu thickness ratios were studied. It was found that the Cu6Sn5 layer within the three Sn layers had different thicknesses and decreased with increasing distance from the heat source of the Al-Ni nanofoil. The thickness difference between adjacent Cu6Sn5 layers at first decreased with the increasing Sn/Cu thickness ratio in these three groups and then remained constant. The shear strength of the bonds varied with the thickness of Cu6Sn5 layer and achieved a high shear strength with a Sn/Cu thickness ratio of 1.6 μm/1 μm, where fracture occurred within the Cu6Sn5 layer near the Cu substrate. The combination of the Sn-Cu multilayer and self-propagating reaction joining process can achieve a good low-temperature bond between Cu substrates with an optimized Sn/Cu thickness ratio, which has a strong influence on the quality of bonds, the Cu6Sn5 morphology, and shear strength.

Morphological Evolution and Growth Kinetics of Interfacial Cu6Sn5 and Cu3Sn Layers in Low-Ag Sn-0.3Ag-0.7Cu-xMn/Cu Solder Joints During Isothermal Ageing

The morphological evolution and growth kinetics of interfacial Cu6Sn5 and Cu3Sn intermetallic compound (IMC) layers between Cu substrates and Sn-0.3Ag-0.7Cu-xMn (x = 0 wt.%, 0.02 wt.%, 0.05 wt.%, 0.1 wt.%, and 0.15 wt.%) (SAC0307-xMn) solders were investigated. After ageing, the uneven scallop-like morphology of Cu6Sn5 transforms into a layer-like morphology, and the Cu3Sn morphology remains layer-like. Kirkendall voids at the Cu/Cu3Sn interface and in the Cu3Sn layer are observed at high ageing temperatures. The Cu6Sn5 layer predominantly governs the growth of the total IMC layer at low ageing temperatures, whereas the Cu3Sn layer primarily influences the total IMC layer at high ageing temperatures. The growth of the Cu6Sn5 and Cu3Sn layers fits a power–law relationship with an exponent between 0.44 and 0.82, indicating that IMC growth is primarily controlled by diffusion but may also be affected by interfacial reactions. The activation energies and interdiffusion coefficients of the Cu6Sn5 and Cu3Sn layers were determined. The addition of Mn nanoparticles strongly affected the growth of the Cu6Sn5 layer but weakly impacted the growth of the Cu3Sn layer, particularly at low ageing temperatures. Adding Mn nanoparticles to the SAC0307 solder can evidently increase the activation energy of the Cu6Sn5 layer, reduce the atomic diffusion rate, and inhibit the excessive growth of the Cu6Sn5 IMC.

Synchrotron radiation imaging study on the rapid IMC growth of Sn–xAg solders with Cu and Ni substrates during the heat preservation stage

Synchrotron radiation X-ray real-time imaging technology was used to study the interfacial reactions of Sn and Sn3.5Ag solders with Cu and Ni substrates during the heat preservation stage. This experiment allows us to in-situ observe the interfacial intermetallic compounds (IMCs) growth, provides a stage to distinctly separate their growth at isothermal reflow and cooling durations, and thus avoids the measurement errors for size and morphology of interfacial IMCs. The results show that the Cu6Sn5 morphology is scalloped at Sn–xAg/Cu interfaces, whereas (Cu,Ni)6Sn5 is wide-stripe shaped at Sn–xAg/Ni interface during the heat preservation stage. It is interesting to note that the grain boundary molten liquid gaps is observed at both of the Sn3.5Ag/Cu and Sn3.5Ag/Ni interfaces. Compared with pure Sn solder, Sn3.5Ag solders are observed with interfacial IMC of greater thickness, smaller base width, lower aspect ratio and more substrate consumption. In addition, it is confirmed that Ag3Sn grains appear in Sn3.5Ag solder, but not on the surface of existing interfacial Cu6Sn5 grains at Sn3.5Ag/Cu interface during the heat preservation stage. All of the growth kinetic index (n) for Sn–xAg/Cu is close to 1/3 indicating that grain boundary diffusion determines the interfacial reaction at the heat preservation stage. The mechanism by which Ag addition affects interfacial reaction and changes the mirostructure of solder matrix through creation of grain boundary gaps and decrease of the growth activation energy of IMC is also clarified. The knowledge for morphology and thickness control of interfacial IMCs by alloy elements addition as outlined by this study can be utilized to improve the reliability of solder joints in electronic packaging and solar photovoltaic (PV) cells array manufacturing sectors.

Formation mechanism and kinetic analysis of the morphology of Cu6Sn5 in the spherical solder joints at the Sn/Cu liquid–solid interface during soldering cooling stage

The morphology evolution mechanism and dynamics of Cu6Sn5 intermetallic compound (IMC) in cooling stage were studied by using pure Sn solder ball with a diameter of 1 mm to react with polycrystalline Cu substrate and form Cu6Sn5. A nearly uniform height of the scallop-like IMC grains is attained by using high pressurized air to remove excess liquid solder (that is, for acquisition of the IMC morphology identical to heat preservation stage). But the morphology evolution of IMC in the solder joint was greatly affected by the cooling phase of interfacial reaction, and IMC morphology partition phenomenon was found in the spherical joints. The IMC at the edge portion characterized scallop morphology whereas the central portion possessed prismatic shape morphology. Finite element simulation for the temperature field distribution in the solder ball-substrate domain showed temperature gradient in solder’s internal core was significantly greater than that at the edge. Using this simulation results with kinetic equations, it could be understood that the central core region is conducive to the formation of small plane structure morphology. These small planes would eventually form the prismatic morphology IMC in the central region. As the soldering temperature increases, the area ratio of IMC with scallop-like morphology to the prismatic shaped IMC reduced from 0.2178 down to 0.1680. Moreover, for an elevated temperature of 300 °C, it is observed that the central region IMC (with prismatic structure) grows upto an average thickness of 7.7245 μm, whereas the thickness value for scalloped IMC at the edge portion is around 4.556 μm.

Effects of Ni and TiO2 additions in as-reflowed and annealed Sn0.7Cu solders on Cu substrates

The growth of Cu6Sn5 and Cu3Sn5 interfacial layers after isothermal annealing and the resultant effect on the solder joint strength are studied in TiO2 and Ni containing Sn0.7Cu solders. These composite solders were fabricated using a powder metallurgy method and reflow soldered on a Cu substrate printed circuit board (PCB) with an organic soldering preservative (OSP) surface finish. With TiO2 additions, a more planar scalloped Cu6Sn5 morphology was observed with reduced interfacial boundary grooves while a fine scallop-shaped interfacial (Cu,Ni)6Sn5 layer was observed in Ni containing solder joints. The interfacial layer was further suppressed with a combination of Ni and TiO2 even after annealing which resulted in superior shear strength and fracture energy.

In situ quantitative study of microstructural evolution at the interface of Sn3.0Ag0.5Cu/Cu solder joint during solid state aging

In situ microstructural evolution at the interface of Sn3.0Ag0.5Cu/Cu solder joint during solid state aging was quantitatively studied by nanoindentation. The morphology of Cu6Sn5 gradually altered from scallop type to layer type. Though the growth of IMCs was diffusion-controlled, the consumption of Cu substrate was not linear with the square root of aging time. At the initial stage of solid state aging, the Cu atoms essential to the growth of IMCs were mainly from the supersaturated solder matrix. When the Cu atoms from supersaturated solder matrix were exhausted, the Cu atoms for the growth of IMCs were primarily from the Cu substrate. In addition, the IMCs formed at this state were principally used to fill up the gaps between scallops. After the gaps disappeared, the consumption of Cu substrate slowed down. Furthermore, the growth of Cu3Sn layer in Sn3.0Ag0.5Cu/Cu solder joint was on the both sides with layer type. Since the Sn atoms were inhibited to diffuse into the Cu substrate by the alloying elements of Ag and Cu, the thickness of Cu3Sn layer in SnAgCu/Cu solder joint was much thinner than that in pure Sn/Cu solder joint.

Effects of metallic nanoparticle doped flux on the interfacial intermetallic compounds between lead-free solder ball and copper substrate

Lead free solders currently in use are prone to develop thick interfacial intermetallic compound layers with rough morphology which are detrimental to the long term solder joint reliability. A novel method has been developed to control the morphology and growth of intermetallic compound layers between lead-free Sn–3.0Ag–0.5Cu solder ball and copper substrate by doping a water soluble flux with metallic nanoparticles. Four types of metallic nanoparticles (nickel, cobalt, molybdenum and titanium) were used to investigate their effects on the wetting behavior and interfacial microstructural evaluations after reflow. Nanoparticles were dispersed manually with a water soluble flux and the resulting nanoparticle doped flux was placed on copper substrate. Lead-free Sn–3.0Ag–0.5Cu solder balls of diameter 0.45mm were placed on top of the flux and were reflowed at a peak temperature of 240°C for 45s. Angle of contact, wetting area and interfacial microstructure were studied by optical microscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was observed that the angle of contact increased and wetting area decreased with the addition of cobalt, molybdenum and titanium nanoparticles to flux. On the other hand, wettability improved with the addition of nickel nanoparticles. Cross-sectional micrographs revealed that both nickel and cobalt nanoparticle doping transformed the morphology of Cu6Sn5 from a typical scallop type to a planer one and reduced the intermetallic compound thickness under optimum condition. These effects were suggested to be related to in-situ interfacial alloying at the interface during reflow. The minimum amount of nanoparticles required to produce the planer morphology was found to be 0.1wt.% for both nickel and cobalt. Molybdenum and titanium nanoparticles neither appear to undergo alloying during reflow nor have any influence at the solder/substrate interfacial reaction. Thus, doping of flux with appropriate metallic nanoparticles can be successfully used to control the morphology and growth of intermetallic compound layers at the solder/substrate interface which is expected to lead to better reliability of electronic devices.

Effect of electroplating layer structure on shear property and microstructure of multilayer electroplated Sn–3.5Ag solder bumps

In this paper, Sn–3.5Ag solder bumps were prepared using multilayer electroplating method. The effect of electroplating layer structure (Sn/Ag, Ag/Sn, Ag/Sn/Ag) on shear property and microstructure of solder bumps was investigated.Shear test revealed that Sn/Ag bumps displayed the highest shear strength among different electroplating layer structures, which was 89.3% higher than that of pure Sn bumps, and 43.5% higher than that of Ag/Sn bumps. The interfacial microstructure evolution during reflowing process was also observed. It was found that Cu6Sn5 intermetallic compound formed at the interface between solder and Cu and its grain size increased as reflow time increased for all three electroplating structures. When there was Ag electroplated between Sn and Cu (Ag/Sn/Ag and Ag/Sn structures), the morphology of Cu6Sn5 was thin, hexagonal and scattered, which could be attributed to the adsorption of Ag3Sn on the surface of Cu6Sn5. In contrast, when Sn was electroplated on Cu directly (Sn/Ag structure), the morphology of Cu6Sn5 was thick, rod-like and continuous, which displayed high shear strength.

Single-joint shear strength of micro Cu pillar solder bumps with different amounts of intermetallics

This study investigates the effects of intermetallics (IMCs) on the single-joint shear strength of 50μm diameter Cu pillar bumps joined with Sn–4.0%Ag–0.5%Cu (SAC405) solder caps. The correlations between the shear strength of the Cu pillar bumps and the IMCs aged at 180°C for 150, 300, 500, and 750h are studied. Microstructure characterization reveals that the Cu6Sn5 morphology transforms from scallop-type to planar-type after 150h of aging. Void formations are observed at the Cu3Sn/Cu interface after 300h of aging and the amount of void formations increases with aging time. The shear test result shows that the shear strength decreases with aging time. Although the void formations did contribute to the deterioration of the solder joint strength, the main contributing factor was the planarization of the Cu6Sn5 morphology through the aging process. The failure modes of the solder joint are also discussed in this study.

Cu6Sn5 Morphology Transition and Its Effect on Mechanical Properties of Eutectic Sn-Ag Solder Joints

The morphologies of Cu6Sn5 grains formed at the interface between Sn-3.5Ag (wt.% unless otherwise specified) and Cu substrates were studied in this work. Reflow experiments were performed for 60 s at peak temperatures of 513 K, 533 K, 543 K, and 553 K. Two morphologies of interfacial Cu6Sn5 grains were observed in wetting reactions: prism type, above 543 K, and scallop type, below 533 K. During aging, the two morphologies gradually transitioned to layer type. These three morphologies could be transformed into each other as long as the corresponding condition changed. The morphology transition of Cu6Sn5 in the wetting reaction was explained by the change in Jackson’s parameter with temperature. In addition, the effect of the Cu content in molten solder on interfacial Cu6Sn5 grains was examined. Significant differences in shear strength were observed for solder joints with different interfacial Cu6Sn5 morphologies in the case of a lower shear height. Joint strength is discussed in terms of the microstructure of the solder matrix and the morphology of interfacial Cu6Sn5 grains.

Kinetics of Intermetallic Compound Formation at the Interface Between Sn-3.0Ag-0.5Cu Solder and Cu-Zn Alloy Substrates

The growth kinetics of an intermetallic compound (IMC) layer formed between Sn-3.5Ag-0.5Cu (SAC) solders and Cu-Zn alloy substrates was investigated for samples aged at different temperatures. Scallop-shaped Cu6Sn5 formed after soldering by dipping Cu or Cu-10 wt.%Zn wires into the molten solder at 260°C. Isothermal aging was performed at 120°C, 150°C, and 180°C for up to 2000 h. During the aging process, the morphology of Cu6Sn5 changed to a planar type in both specimens. Typical bilayer of Cu6Sn5 and Cu3Sn and numerous microvoids were formed at the SAC/Cu interfaces after aging, while Cu3Sn and microvoids were not observed at the SAC/Cu-Zn interfaces. IMC growth on the Cu substrate was controlled by volume diffusion in all conditions. In contrast, IMC growth on Cu-Zn specimens was controlled by interfacial reaction for a short aging time and volume diffusion kinetics for a long aging time. The growth rate of IMCs on Cu-Zn substrates was much slower due to the larger activation energy and the lower layer growth coefficient for the growth of Cu-Sn IMCs. This effect was more prominent at higher aging temperatures.

スズめっき皮膜／銅基板界面の微視的不均一性評価

Three-dimensional visualization by serial sectioning and deformation analysis by EBSD were performed for detailed microscopic evaluation of the interface between an electroplated film of tin and a copper substrate. Three-dimensional morphology revealed that the intermetallic compound of Cu6Sn5 developed nonuniformly from the tin grain boundaries, which are thought to be preferred nucleation sites of Cu6Sn5. Results further showed that the whisker root grain coarsened in the plated plane because of incoming tin atoms and consequent grain boundary movement. Scanning ion microscopy and a kernel average misorientation map showed that copper deforms locally as Cu6Sn5 develops at the interface between the electroplated film and substrate. The mode of the local deformation of copper adjacent to Cu6Sn5 was evaluated using pattern analysis of EBSD. The tensor, which describes the local deformation, showed that rotation and shear strain were introduced because of the volume change in the Cu6Sn5 formation. The nonuniform morphology of Cu6Sn5 and resultant local deformation of copper suggest nonuniform deformation in the tin film, which might induce tin atom diffusion and promote whisker growth.