Shear Strength Of Solder Joints Research Articles

Thermal Cycling Performance of Heterogeneous Solder Ball Joints with Sn-3.0Ag-0.5Cu and Sn-0.75Cu(-Ni,Bi) Solder Ball Composition for BGA Package

Sn-3.0Ag-0.5Cu (SAC305) is one of the most commonly used Pb-free solder composition nowadays. A minor alloying element addition can improve mechanical properties and thermal reliability of the solder joint. Minor amount of Bithmuth (Bi) or Nickel (Ni) addition can improve mechanical properties of solder by solid solution strengthening, or ensure the structural stability of the intermetalllic compounds. Also, low melting temperature solder with Bithmuth can reduce the cost of soldering process and keep components from deterioration. In this study, reliability of heterogeneous and homogeneous solder joint in the ball-grid-array (BGA) package solder joint were investigated. Using Sn-3.0Ag-0.5Cu (SAC305) solder paste and two kinds of solder balls, we have investigated which combination of solder joint improves the thermo-mechanical reliability. SAC305 and SCN (Sn-0.75Cu-Ni,Bi) balls were used for homogeneous and hetrogeneous joints. Solder balls were attached in BGA package. To examine the solder joint reliability, thermal cycling test was conducted after reflow soldering. Shear strength measurement and cross-sectional analysis of the BGA package solder joints were carried out before and after 2000 cycles of the test. The shear strength of homogeneous solder joint decreased to 68.2% and heterogeneous decreased to 43.5%. The cross-sectional analysis using scanning electorn microscopy (SEM) and electorn back-scattered diffraction (EBSD) showed the (Ni,Cu)<sub>6</sub>Sn<sub>5</sub> and Cu<sub>6</sub>Sn<sub>5</sub> IMCs which were generated in the solder joint, and the crack propagated longer in the homogeneous solder joint of SAC305 after the thermal cycling test. IPFM showed the grain refinement effect of the SCN solder joint after thermal cycling. The minor addition of Bi had played a role as dislocation pinning site and became to equiaxied grain, so that the lifetime of heterogeneous SCN solder joint was superior than that of the SAC305.

Comparing the Solderability of Different SA C0307 Composite Solder Pastes

In the present study, the effect of four oxide ceramics (TiO2, ZnO, ZrO2, and CuO) as reinforcements were investigated on the soldering parameters of the SAC 0307 solder alloy. The oxide ceramics were used in nano-powder format. Composite solder pastes were composed by the standard ball milling process of the nano-particles into the SAC 0307 solder paste in 0.25wt% weight fraction. The wettability, shear strength, and microstructure of the composite solder joints were studied and compared. The ceramic nano-particles did not have a major effect on the wettability of the solder. Shear strength increases were observed at the composite joints, except in the case of ZnO. Generally, Sn grain refinement was found in the Sn-matrix which could be the reason for the shear strength increase.

Interface reactions between copper and 50In-50Pb (wt%) alloy by solid-state aging

This study investigated the interface microstructure that developed between 50In-50Pb (wt%) solder and copper (Cu) base material as a function of solid-state aging. The aging temperatures and times were in the range of 55°C – 170°C and 1 – 350 days, respectively. The analysis examined the intermetallic compound (IMC) layer compositions; the rate kinetics of IMC layer growth; and the role of the IMC layer on solder joint shear strength. The IMC layer transitioned from pseudo-equilibrium compositions towards an equilibrium composition of Cu11In9 (φ phase) with an increased degree of aging, illustrating the non-equilibrium nature of the interface. The rate kinetics for solid-state IMC formation exhibited a time exponent, n, of 0.47±0.09, which indicated a diffusion-controlled reaction. The relatively low, apparent activation energy, ΔH, of 23±4 kJ/mol implied an anomalously-fast diffusion mechanism. The shear stresses were 22±2 MPa and 19±1 MPa for the 0.190 mm and 0.380 mm joint clearances, respectively, representing the as-fabricated condition; the difference reflected the plane strain effect. The crack path remained in the In-Pb solder so that the In-Pb microstructure, not the thickness, composition, or morphology of the IMC layer, controlled shear strength for either joint clearance. The shear strength trends differed between joint clearances due to competing processes in the In-Pb solder. Precipitation and re-solutionization of Cu dissolved in the In-Pb solder controlled the effects of aging on the shear strength of the 0.190 mm joint clearance while traditional recovery and recrystallization mechanisms determined the aging response of the 0.380 mm solder joints.

Improvement of Solder Joint Shear Strength under Formic Acid Atmosphere at A Low Temperature.

With the continuous reduction of chip size, fluxless soldering has brought attention to high-density, three-dimensional packaging. Although fluxless soldering technology with formic acid (FA) atmosphere has been presented, few studies have examined the effect of the Pt catalytic, preheating time, and soldering pad on FA soldering for the Sn-58Bi solder. The results have shown that the Pt catalytic can promote oxidation-reduction and the formation of a large pore in the Sn-58Bi/Cu solder joint, which causes a decrease in shear strength. ENIG (electroless nickel immersion gold) improves soldering strength. The shear strength of Sn-58Bi/ENIG increases under the Pt catalytic FA atmosphere process due to the isolation of the Au layer on ENIG. The Au layer protects metal from corrosion and provides a good contact surface for the Sn-58Bi solder. The shear strength of the Sn-58Bi/ENIG joints under a Pt catalytic atmosphere improved by 44.7% compared to using a Cu pad. These findings reveal the improvement of the shear strength of solder joints bonded at low temperatures under the FA atmosphere.

Strong composite SnAgCu solder joints with internal aligned carbon fibers by magnetic field

Lightweight carbon fibers with high mechanical performance are referred to as an ideal reinforcement for an extensive variety of composite materials. However, the addition of carbon fibers into electronic interconnection solders is extremely limited so that the expected reinforcement in the mechanical properties of the composite solder joints has not been completely realized. Here, we used magnetic fields to align Ni-coated carbon fibers in the Sn-3.0Ag-0.5Cu solder vertically with the Cu substrate and prepared the oriented composite solder joints. We achieved a further improvement in the shear performance of composite solder joints (∼58 MPa) with a small addition of Ni-coated carbon fibers (0.5 wt%), which is 25% higher than that of pristine joints. It is found that these vertically oriented carbon fibers changed the propagation path of shear cracks and thus increased the shear resistance. Ni-coated carbon fibers also promoted nucleation of interfacial Cu6Sn5 in the solder joints during reflow, but prevented the formation of brittle Cu3Sn phase during isothermal aging, thus ensuring the high shear strength of composite solder joints after isothermal aging. This success provides a new pathway to fabricate a strong composite solder joint with a limited addition of reinforcements by aligning their orientation.

A strategy to improve the thermal fatigue resistance of solder joints based on amorphous Co-P coating to spontaneously build skeleton of CoSn3 laths

Integrated circuit systems are always suffering the temperature cycling environment caused by frequent power on and off. Mismatch in thermal expansion coefficients among chip package components will cause severe cyclic stress to the solder joints. During thermal fatigue, β-Sn grains tended to generate thermal fatigue cracks at the grain boundaries. This work proposed a strategy of using amorphous Co-15 at.% P coating as the interface layer to inhibit the initiation and propagation of thermal fatigue cracks and improve the shear strength of solder joints by numerous endogenous CoSn3 laths. Mechanistically, based on the amorphous structure of the Co-P coating, Co atoms would massively and rapidly diffuse into the molten solder during the liquid-solid diffusion stage of reflow soldering, and the eutectic solidification together with β-Sn spontaneously precipitated numerous laths of CoSn3 intermetallic compounds (IMC), which were evenly distributed and became the skeleton of the solders. The skeleton-like CoSn3 laths with high elastic modulus were the reinforcing phase of Sn-based solder, but also refined the grains of β-Sn. The refinement of β-Sn grains and the strengthening of CoSn3 laths played an important role in inhibiting the initiation and propagation of thermal fatigue cracks. In addition, a discontinuous Co-Sn IMC layer was formed between the amorphous Co-P and the solder. The alternating appearance of CoSn3 and relatively soft β-Sn at the interface avoided the generation of cracks at the interface during temperature cycling.

Ceramic-to-metal bonding using rare-earth containing Sn–Bi solder

With the increasing miniaturization and power of optoelectronic devices, direct bonding of optical substrates like semiconductors and ceramics to metal heat sinks using low melting-point solder has gained significant interest. In this study, we demonstrated the bonding of glass to copper using Sn-58 wt% Bi solder (SB solder) doped with a small amount of rare earth (RE) elements. The RE elements act as active agents that facilitate the bonding to glasses without glass metallization. By optimizing the bonding parameters, such as reflow temperature and time, and employing an inert gas atmosphere to prevent solder or RE oxidation, we successfully achieved the highest shear strength in glass-copper solder joints using SB-RE solder, without the need for ultrasonic-assisted soldering (UAS). These results demonstrate the potential of using RE-containing solder for bonding unmetallized glass and ceramics in optoelectronic devices with metals at low soldering temperatures (< 200 °C). Furthermore, analysis of the shear strength and failure morphology of solder joints revealed only small degradation, primarily originating from the bulk solder region rather than the solder-glass interface, after both thermal aging (100 h) and cycling tests (100 cycles). The establishment of low-melting point RE-containing solders opens the possibility of direct jointing ceramic optoelectronic substrates to metal heat sinks for more efficient heat dissipation. In the meantime, our work also suggests that further optimization studies are necessary to explore its performance under more extreme working conditions.

Preparation, characterization and mechanical properties analysis of SAC305-SnBi-Co hybrid solder joints for package-on-package technology

The development of hybrid solder for chip packing is a major 3D packaging research topic. The incorporation of with low melting points into solder materials has been used in low-temperature packaging. Hybrid solder struggles to enhance low-temperature solder efficiency and mechanical properties. This work examined the effects of Co elements on microstructure and intermetallic compound (IMC) morphology of SAC305-SnBi-Co hybrid solder generated by reflow welding on electroless nickel immersion gold (ENIG) substrate at various temperatures. Moreover, mechanical characteristics and failure behavior of joints were extensively explored. The results show that the addition of 0.05% Co reduced the melting range of the solder and improved the wettability of SnBi solder. According to transmission electron microscopes (TEM) and electron diffraction spots (EDS), the crystal structure of the grains is (Cu, Co)6Sn5 basic-centered monoclinic crystal. Fourier analysis of high-resolution images yields deformed lattice fringes, indicating that Co atoms fill Cu6Sn5's lattice gap in IMC. The shear strength of SAC305/SnBi hybrid solder joints with Co rises and then decreases with temperature. The highest shear strength of solder joints with 0.05% Co (40 nm) is 73.2 MPa at 220 °C, whereas joints with 0.1%Co are 67.5 MPa. Combined with the fracture morphology, the proportion of IMC fracture mode decreased after adding Co element.

Effect of Nano-Cu6Sn5 upon development mechanism of Cu–Ni–Sn compounds and mechanical characteristics for mixed solder joints

This investigation aimed to examine the development mechanism of Cu–Ni–Sn compounds and analyze the mechanical properties of mixed solder (MS) joints. Results show that an intermetallic compound (IMC) layer was formed in an SAC305 solder joint prepared herein comprising (Ni, Cu)3Sn4 and (Cu, Ni)6Sn5 phases following the reflow process. The morphology of the (Cu, Ni)6Sn5 grains was identified to be dodecahedral. Meanwhile, the IMC layer of the prepared MS joints contained only the (Cu, Ni)6Sn5 phase, which exhibited a hexagonal prism morphology. The lattice characteristics of Cu6Sn5 changed after Ni dissolution, forming (Cu, Ni)6Sn5 crystals with an X-shaped morphology in the MS joints that exhibited a high Cu content during the aging process. After reflow, the MS joints exhibited slightly higher shear strength than the SAC305 solder joint. After aging at 165 °C for 1000 h, the shear strength of the SAC305 solder joint reduced by 21.72% compared to its value after reflow owing to the annexation of Sn grains. However, the number of Sn grains in the MS joints did not considerably decrease after aging. Further, the grain boundaries of β-Sn and (Cu, Ni)6Sn5 particles contributed to the strengthening of the MS joints. The shear strength of the MS joints decreased by 11.06%–18.35% after aging.

Dynamics of corrosion on mechanical and electrical reliability of SAC305 solder joints during salt spray test

This paper, concerns the impact of a corrosion evolution on mechanical and electrical reliability of solder joints during salt spray tests. Focus is made in test vehicle resistors (1210) soldered with a SAC305 lead-free solder. Solder joints resistors were electrically and mechanically tested and aged from 24 to 96 h in a salt spray chamber with one salinity of 5 % NaCl at five temperatures ranging from 25 °C to 45 °C. The shear strengths of SAC305 solder joints decreased with increasing temperature and corrosion time. No electrical failure was observed. However, the solder joints deterioration is visible by cross-section after 72 h at 25 °C, 60 h at 30 °C, 48 h at 35 °C, 36 h at 40 °C and 24 h at 45 °C. Moreover, the corrosion has a significant effect on the mechanical strength of lead-free solder joints. A relationship between the mechanical behaviour and the dynamics of corrosion of the solder joints has been established. In addition, although the corrosion product remains the same, the corrosion dynamics of the solder material (alloy) and the solder joint (assembly) are very different: the corrosion kinetics is significantly less in the solder material than in the solder joints.

Study on the properties of epoxy-based Sn[sbnd]58Bi solder joints

In electronic packaging technology, Sn58Bi alloy solder has the advantages of low-temperature soldering and high shear strength of solder joint. It has a wide range of application in the electronics industry for low-temperature soldering, especially for temperature-sensitive substrates. Epoxy-based Sn58Bi solder paste is a mixture of curable flux and Sn58Bi solder powder. During the soldering process, the curable flux, in addition to the functions of a conventional flux, forms a cured epoxy shell around the periphery of the solder joint, which can effectively improve the shear strength and thermal stability of the solder joint. In this study, a self-made epoxy-based Sn58Bi solder paste was prepared and the properties of the solder joints were investigated. The results show that epoxy-based Sn58Bi solder paste has better wettability than traditional Sn58Bi solder paste without epoxy resin. And the shear strength of epoxy-based Sn58Bi solder joint is about 25 % higher than that of traditional Sn58Bi solder joint. Furthermore, the electrical conductivity of epoxy-based Sn58Bi solder joint has the same order of magnitude as that of traditional Sn58Bi solder joint, which means that non-conductive epoxy resin has no effect on the electrical conductivity of the epoxy-based Sn58Bi solder joint.

Minor Ag inducedshear performance alternation in BGA structure Cu/SnBi/Cu solder joints under electric current stressing

In this work, the effect of minor Ag addition on shear performance of ball grid array (BGA) structure Cu/SnBi/Cu solder joints under electric current stressing was investigated. The results show that the shear strength of solder joints decreased with increasing current density, and the effect of Ag addition on shear strength changed from an elevating state to a deteriorating state. The elevating effect of Ag addition was due to the dominance of Sn/Bi phase refinement and Ag3Sn dispersion, which was weakened gradually with the increase in current density. The deteriorating effect of Ag addition was attributed to the more inhomogeneous distribution of current density and higher thermal gradient induced by the finer phase of the solder matrix as well as the consequent severer strain mismatch at the Sn/Bi phase interface. The finer Sn/Bi phase was also conductive to easier lattice atom migration under current stressing, resulting in a rapid decrease in shear strength. Moreover, the dominant factor on the shear strength reduction tended to change from Joule heating to athermal effect of current stressing. The fracture of solder joints indicated an insignificant influence by the Ag addition, which all occurred in the solder matrix in a ductile mode.

Preparation and performance of Sn-based composite solder joints by solid-liquid low-temperature solder bonding technology

In the era of big data, the advantages of 3D packaging are becoming increasingly significant. In addition, the mismatch between the coefficient of thermal expansion (CTE) of the PCB and BGA components leads to dynamic warpage of the system, and the expansion and innovation of low-temperature soldering have been a new trend. We developed a fully mixed solder joint of a SAC305(Sn-3.0Ag-0.5Cu wt.%) solder ball and Sn–58Bi(wt.%) solder paste by solid-liquid low-temperature solder bonding technology. The mixing degree and diffusion process of the two were calculated and simulated by mathematical calculation and COMSOL Multiphysics. The results show that a completely mixed solder joint can be obtained after reflow at 210 °C for 5 min. The average shear strength of the composite solder joints was 63.68 ± 1.12 MPa, which was about twice that of the single SAC305 and Sn58Bi solder joints, and the shear fracture was a composite mode of brittle and ductile fracture, which appeared in the IMC and the solder, respectively. After complete mixing, the solder wettability angle was less than 26.68°, with outstanding wetting properties. No phase transition occurred after aging, the distribution of each phase remained uniform, and no enrichment of the brittle phase was observed at the interface. The shear strength decreased slightly with aging time, and the reduction value was less than 10 MPa, which has good reliability.

Study on the Influence of Vacuum Vapor Phase Soldering Process Technology on SiP Component

Vapor phase soldering (VPS) is used in the assembly of highly reliable electronic products for aerospace, military, and industrial area for the advantages of heat transfer coefficient, good temperature uniformity, and controllable maximum soldering temperature. VPS is usually used for PCB (Printed Circuit Board) and complex components. However, little research has been done on the application of VPS process technology on the SiP (System in Package) component in the process of solder ball or solder column package. In this work, we investigated the influence of the vacuum VPS process on the SiP component. The advantages of VPS and vacuum process were discussed and the maximum shear strength of solder joints in the vacuum process was calculated. The vacuum process has no impact on the internal structure of the SiP component.

Microstructures and shear strengths of W-ball solder joints aged under isothermal and cyclic thermal conditions

Microstructures and shear strengths of W-ball solder joints aged under isothermal and cyclic thermal conditions

Effect of Ni-modified reduced graphene oxide on the mechanical properties of Sn–58Bi solder joints

Sn–58Bi solder has great research value as a low-temperature solder. However, it still requires strengthening due to a lot of brittle Bi-phase, which reduces mechanical reliability. In this study, Ni-modified reduced graphene oxide (rGO@Ni) was prepared by heat reduction, and mechanical stirring was used to manufacture rGO@Ni-reinforced Sn–58Bi composite solder. The distribution, phase composition, and structural changes of graphene and Ni nanoparticles during enhancer synthesis were characterized in detail by Scanning Electron Microscope, Energy Dispersive Spectroscopy Raman and Fourier Transform Infrared spectra, X-ray Photoelectron Spectroscopy, X-ray Diffraction, and Transmission Electron Microscope. Besides, the morphology of intermetallic compound (IMC) layers of the composite solder/Cu interface was investigated. The thickness of the IMC layer decreases with the increase of rGO@Ni content. The microstructure analysis demonstrated that the rGO@Ni distributed near the IMC layer, which limits the diffusion of metal atoms and decreases the IMC layer's growth rate during the reflowing process. Besides, compared with Sn–58Bi solder alloys, the addition of 0.01 wt% rGO@Ni can increase the shear strength by up to 15%. However, when the content of rGO@Ni is more than 0.05 wt%, it agglomerates inside the composite solder, resulting in a decrease in the shear strength of the composite solder joint.

Effect of Graphene Nanosheets on the Microstructure and Mechanical Properties of Sn-20Bi Solder.

The application of Sn-Bi series solder is limited due to the brittleness of Bi phase. Sn-20Bi solder with less Bi element content has great research prospects, but it needs modification to make it a substitute for traditional Sn-Pb solder. In this article, we mixed graphene nanosheets with nanometer Sn powder by means of ultrasonic oscillation, and Sn-20Bi-qGNS (q = 0.01, 0.02, 0.04, 0.06, and 0.1 wt.%) solder alloys were prepared by the melt-casting method. The effects of graphene nanosheets (GNSs) on the microstructure, physical properties, mechanical properties, and corrosion resistance of solder alloys were investigated. Scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used to determine the microstructural morphology and composition. The results showed that the melting point, density, and wettability of the solder decreased slightly with the addition of GNSs. The addition of GNSs as a second phase refined the solder structure and improved the tensile strength of the molten Sn-20Bi composite solder to 99.6 MPa, while elongation decreased with the addition of GNSs. Furthermore, GNSs prevented the MC Sn-20Bi-qGNSs/Cu intermetallic compound layers' growth by interfering with atomic diffusion and grain boundary movement. In addition, the addition of 0.02 wt.% GNSs enhanced the shear strength of MC Sn-20Bi solder joints to 46.3 MPa. The electrochemical experimental results show that the surface corrosion products of MC Sn-20Bi-qGNSs under 3.5% NaCl solution were Sn3O(OH)2Cl2, with MC Sn-20Bi-0.01GNSs exhibiting the best corrosion resistance.

Effect of IMC Thickness on the Mechanical Properties of Microbumps

With the continuous development of electronic products towards high density and small size, the size of interconnecting solder joints also continues to decrease. Under normal service conditions, micro-solder joints will be subjected to multiple loads at the same time, which in turn will cause many reliability problems in the package structure. This paper focuses on the growth pattern of IMC (Intermetallic compounds) during hot-press bonding and analyses its effect on the shear strength and creep properties of copper pillar micro-bumps. Firstly, the solder joints with different IMC thicknesses were obtained by adjusting the bonding parameters during the thermal compression bonding process, and the growth pattern of IMC during the thermal compression bonding process was analyzed. Secondly, shear experiments were conducted on solder joints with different IMC thicknesses, and the effects of IMC on the shear strength and shear fracture mode of solder joints were analyzed. Finally, creep experiments were performed on cylinder-shaped solder joints with different IMC thicknesses under different stress conditions. The results show that throughout the bonding process, copper atoms migrate under the combined effect of temperature gradient (JTM) and concentration gradient (JCM), and IMC shows asymmetric growth, and the growth rate of IMC gradually decreases with the increase of bonding holding time. Under the same temperature conditions, the shear strength of the solder joint shows a trend of increasing and then decreasing with the increase of holding time. In addition, with the increase of IMC thickness, the shear fracture mode of solder joints changes from ductile fracture in the initial stage to tough-brittle combination fracture and finally evolves to brittle fracture. With the continuous increase of stress, the steady-state creep strain rate of all solder joints increases, and the fracture location tends to be closer to the intersection of the solder and the copper pillar from inside the solder joint. With the increase of IMC thickness, the steady-state creep strain rate of solder joints shows a trend of decreasing and then increasing.

Shear deformation behavior and failure mechanisms of graphene reinforced Sn-based solder joints bonded by transient current

Graphene as a reinforcement is expected to improve the shear strength of solder joint. However, little is known about the deformation behavior and mechanisms of composite solder joints. In this study, sandwich joints are prepared using graphene nanosheets-reinforced Sn-Ag-Cu composite solder (GNSs/SAC) by transient current bonding technology in order to obtain dispersed graphene. Interrupted shear tests combined with orientation image microscopy are conducted at different strain to observe the morphology and crystal orientation evolution of solder joints in situ. Some twins rotate, and the orientation begins to spread during shear, while the orientation of large Sn grain shows a minimal change. Cracks tend to initiate and propagate along the boundary. The failure mechanisms of the solder joint is determined. Molecular dynamics results show that the strain concentration at the boundary. Continuous shear tests show that the shear strength was improved by approximately 50.7% with the addition of 0.1 wt% graphene. Based on microstructure analysis and calculation, load transfer is identified as the dominant strengthening mechanism for GNSs/SAC alloys, followed by Orowan system. Graphene does not refine the grain size of solder joints, and dislocation multiplication from thermal mismatch does not strengthen them.

Effect of Aging Temperature on the Fatigue Resistance and Shear Strength of SAC305 Solder Joints

The interconnection materials that are used in electronics assembly fabrication operating in harsh environmental conditions are frequently exposed to different types of mechanical stress and fatigue. Fatigue resistance does significantly affect the reliability of electronic assemblies. SAC alloys are commonly utilized in electronic assemblies’ fabrication operating in harsh conditions due to their superior mechanical and fatigue properties. Hence, this provokes the need to model and perform a detailed statistical analysis of their reliability behavior. SAC305 is commonly used as a lead-free alloy which is being utilized as a replacement of the eutectic SnPb alloy. The main goal of this study is to investigate the effect of aging temperature on the fatigue and mechanical behavior of SAC305 solder joints using accelerated shear-fatigue and shear tests. An Instron Microtester machine with a customized fixture was used to perform the tests. A two-factor test matrix for the fatigue test was constructed; where the stress amplitude has three levels (16, 20, and 24MPa) and the aging temperature has four levels (0, 50, 100, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$150^{\circ }\text{C}$ </tex-math></inline-formula> ). Microstructural analysis was performed on samples aged at different temperatures using SEM microscopy to address the evolutions in the precipitates size and the intermetallic compound (IMC) layer. A stress-life equation and an Arrhenius model are used to develop a general reliability model as a function of aging temperature and stress amplitude. The relationship between the fatigue life and the inelastic work were analyzed using Morrow Energy equation. The results indicate a major reduction in the reliability and shear strength of the solder joints with increasing the aging temperature. Aging has been also found to have a more notable effect on the fatigue life when compared to shear strength.