Tin-lead Solder Research Articles

Free Chlorine Can Inhibit Lead Solder Corrosion via Electrochemical Reversal.

Galvanic corrosion of lead-tin solder in copper plumbing can be a major contributor to water lead contamination. Here, we report the electrochemical reversal of the copper-solder galvanic couple, in which the normally anodic solder becomes cathodic to copper via a reaction with free chlorine. This reversal occurred after a few months of exposure to continuously circulating water with relatively low pH and low alkalinity, causing dramatically decreased lead release and the formation of a Pb(IV) scale. Chloramine did not similarly inhibit solder corrosion over the 4-9 month test duration, resulting in up to 100 times more lead contamination of the water relative to free chlorine. These findings have major implications for corrosion control and public health and can help explain anomalously low levels of lead contamination in some waters with free chlorine that are normally considered corrosive to solder.

Residual Stress and Warping Analysis of the Nano-Silver Pressureless Sintering Process in SiC Power Device Packaging.

Chip bonding, an essential process in power semiconductor device packaging, commonly includes welding and nano-silver sintering. Currently, most of the research on chip bonding technology focuses on the thermal stress analysis of tin-lead solder and nano-silver pressure-assisted sintering, whereas research on the thermal stress analysis of the nano-silver pressureless sintering process is more limited. In this study, the pressureless sintering process of nano-silver was studied using finite element software, with nano-silver as an interconnect material. Using the control variable method, we analyzed the influences of sintering temperature, cooling rate, solder paste thickness, and solder paste area on the residual stress and warping deformation of power devices. In addition, orthogonal experiments were designed to optimize the parameters and determine the optimal combination of the process parameters. The results showed that the maximum residual stress of the module appeared on the connection surface between the power chip and the nano-silver solder paste layer. The module warping deformation was convex warping. The residual stress of the solder layer increased with the increase in sintering temperature and cooling rate. It decreased with the increase in coating thickness. With the increase in the coating area, it showed a wave change. Each parameter influenced the stress of the solder layer in this descending order: sintering temperature, cooling rate, solder paste area, and solder paste thickness. The residual stress of the nano-silver layer was 24.83 MPa under the optimal combination of the process parameters and was reduced by 29.38% compared with the original value of 35.162 MPa.

Zinc Orthophosphate Can Reduce Nitrate-Induced Corrosion of Lead Solder.

Nitrate-induced spallation of lead-bearing solder particles into drinking water is not sufficiently controlled by phosphate-based inhibitors, although adding zinc can improve their performance. Studies using copper coupons coated with new lead-tin solder in water with up to 12 mg/L nitrate demonstrated that zinc orthophosphate reduced lead release by more than 90% and outperformed orthophosphate alone. Lead release and spallation from harvested pipes with decades-old lead-tin solder in a high nitrate water were improved but not eliminated with zinc orthophosphate over a period of months. When applied at a water utility with high source water nitrate, monthly in-home field sampling showed that 90th percentile lead levels dropped below the action level after dosing zinc orthophosphate at full scale for 6 months. Scanning electron microscopy (SEM) analysis of pipe scales revealed that zinc and orthophosphate codeposit at the copper-solder interface and may act as a mixed inhibitor, with zinc inhibiting the cathodic reaction on the copper pipe, phosphate limiting the anodic reaction, and an added benefit of zinc orthophosphate preferentially precipitating at the galvanic interface between the anode and the cathode. Updates to corrosion control guidance for waters with higher nitrate due to seasonal runoff or source water changes are needed.

Criteria for Solder Alloy Adoption

Solder is a critical component in modern electronic systems – past, present, and future. While solder is used within packaged electrical devices, the highest volume of solder is used for fabrication of printed circuit board assemblies. Historically, tin-lead solder was the dominant solder used in printed circuit board assemblies. However, tin-silver-copper solder replaced tin-lead solder starting in 2006 after European Union regulations banned the use of lead for a wide range of electronic products. Despite the successful transition to tin-silver-copper lead-free solder and over fifteen years of high volume lead-free electronic production, a number of aerospace and defense products have not converted to tin-silver-copper or other lead-free solders over reliability concerns. Reliability should be a concern for all product manufacturers and end-users. This begs the question, what has convinced industries that are currently producing lead-free products that the reliability was sufficient and what is keeping defense and aerospace electronic equipment manufacturers from adopting lead-free solder. This paper reviews decision processes for adopting solder for printed circuit board assembly.

A study on the quantitative recrystallization of cold deformed copper affected by tin-lead solder

It has been observed that the fractional recrystallization characteristics of commercially pure copper is affected by the presence of individual or both the constituent elements of the Sn-Pb solder alloy. In order to design the experiment, commercially pure Cu, binary copper alloys (Cu-Sn and Cu-Pb) and ternary copper alloy, Cu-Sn-Pb are investigated. Cast alloys are homogenized, solution treated, and then quenched to complete the thermal treatment. In order to recrystallize, alloys are cold rolled to a 75% thickness and then annealed at 700°K isothermally for varying durations, up to 3600 seconds. In this experiment, the fractional recrystallization of annealed samples is evaluated as the normalized difference in microhardness recorded at various time steps. Additionally, in an attempt to verify the experimental results, the well-known Johnson-Mehl-Avrami-Kolmogorov equation is also used to predict the associated recrystallization behavior. From the study, it can be inferred that the presence of Sn-Pb solder-alloy elements have a positive impact on the recrystallization behavior of pure copper due to the solid solution strengthening, in which the effect of tin is greater than that of lead. Quantitative analysis indicates that recrystallization of pure Cu, Cu-Sn, Cu-Pb, and Cu-Sn-Pb alloys attains 99.4%, 95.4%, 98.4%, and 89.5%, respectively. Sn forms intermetallic with Cu but Pb does not. Additionally, Sn forms different intermetallic with impurities and has a BCC crystal structure dissimilar to the FCC of Cu and Pb. As a result, the formation of GP zones and the intermetallic phases during annealing show greater differences in the recrystallization behavior between the two approaches. By combination, microstructural studies of the cold-rolled alloys reveal the elongated grains of the second phases, and the alloys almost completely re-crystallized after 1800 seconds of annealing at 700°K.

Self-protected high-temperature superconducting demonstrator magnet for particle detectors

A high temperature superconducting (HTS) demonstration coil has been developed in the frame of the Experimental Physics department Research and Development program at CERN The magnet extends the recent experimental demonstration of aluminium-stabilised HTS conductors and supports the development of future large scale detector magnets. The HTS magnet has five turns and an open bore diameter of 230 mm. Up to 30 K, the coil was measured to be fully superconducting across four central turns at 4.4 kA, the maximum available current of existing power supply. The central magnetic field is 0.113 T, the peak field on the conductor is 1.2 T and the coil has a stored magnetic energy of 0.1 kJ. A 3D-printed aluminium alloy (Al10SiMg) cylinder acts both as a stabiliser and a mechanical support for the superconductor. The resistivity of Al10SiMg was measured at cryogenic temperatures, and has a residual resistivity ratio of approximately 2.5. The ability to solder ReBCO tapes (a stack of four REBCO tapes, 4 mm wide, Fujikura) to Al10SiMg stabiliser, electroplated with copper and tin, forming a coil, is demonstrated using tin-lead solder at 188 ∘C. The HTS magnet was proven to be stable when superconductivity was broken locally using a thin-film heater. Despite voids in the solder joint between HTS and stabiliser, no degradation of the magnet’s performance was observed after 12 thermal cycles and locally quenching the magnet. A numerical model of the transient behaviour of solenoid with partially shorted turns is developed and validated against measurements. Our work experimentally and numerically validates that using an aluminium alloy as a stabiliser for HTS tapes can result in a stable, lightweight and transparent magnet.

Effect of Ti3C2Tx/Ag/MWCNTs/Ag MXene fillers on the electrical conductivity of Ag-coated Cu conductive adhesives

With the rapid development in the field of microelectronic devices, electrically conductive adhesives (ECAs), which are green and easy to connect, are urgently needed as a new alternative to tin-lead solder. Dendritic Ag-covered Cu (Cu@Ag) particles possessing low resistance and the two-dimensional structure of the conductive materials Ti3C2Tx/Ag/MWCNTs/Ag were combined with each other and used as ideal fillers for developing high-performance ECAs. The two-dimensional structure of the Ti3C2Tx/Ag/MWCNTs/Ag materials allowed for the establishment of large conductive paths within the colloid, followed by Cu@Ag particles filling the gaps within the framework as well as within the colloid, effectively increasing the conductive paths. The effect of the filling amount of the two-dimensional conductive materials Ti3C2Tx/Ag/MWCNTs/Ag on the volume resistance of the ECAs was systematically investigated. More importantly, the volume resistivity of ECAs reached 9.19 × 10−6 Ω m when the percentage of filled micron Cu@Ag particles reached 74 %. When further 0.6 g of Ti3C2Tx/Ag/MWCNTs/Ag filler materials were added, the volume resistance reached a minimum of 4.09 × 10−6 Ω m.

Effect of temperature on the low cycle fatigue properties of BGA solder joints

Since the restriction of hazardous substances (RoHS) directive, lead-free soldering has been widely broad adopted. In many applications, lead-free alloys have been substituted for conventional SnPb (Tin-Lead) solder. Among lead-free alloys, SAC305(Sn-3.0Ag-0.5Cu) has gained the highest acceptance as a solder alloy. The fatigue performance of solder joints has become an essential reliability assessment criterion due to the transition to more reliable lead-free alloys from highly predictable lead-based alloys. This study examines the shear fatigue characteristics of sandwich test vehicles for SnPb and SAC305 at different temperatures using both Organic Solderability Preservative (OSP) and Electroless Nickel-Immersion Silver (ENIG) surface finishes. The fatigue experiments were performed using an Instron micromechanical tester at a constant strain rate, and microstructural analysis was carried out using Scanning Electron Microscopy (SEM) to identify the Intermetallic Compound (IMC) morphology and failure mode. The stress-strain (hysteresis) loops of SnPb and SAC305 were measured, and the fatigue life of the specimens was estimated using the strain-life equation at various temperatures. SAC305 was observed to have a better fatigue life than SnPb, particularly at higher strain levels or testing temperatures. The OSP surface finish demonstrated superior fatigue properties compared to the ENIG surface finish. Additionally, elevated testing temperatures were found to accelerate fatigue failure in solder joints. The Arrhenius model was utilized to develop a general empirical model that predicts the fatigue life of SAC305 and SnPb solder alloys with OSP and ENIG surface finishes as a function of the strain level and testing temperature.

Fabrication of hollow silicon millispheres through a coaxial nozzle, with observation of a novel horn structure

Hollow silicon millispheres have been fabricated using a hollow coaxial jet for the first time. Silicon was melted in a graphite crucible at 1823 K, then ejected from the annulus of a coaxial nozzle as argon gas was injected from an inner nozzle whose inner and outer diameters are 0.4 mm and 1 mm respectively. Sphere diameters were 1–2 mm with spherical outer surfaces, and the frequency of formation was approximately 145 Hz. The wall thicknesses varied gradually between antipodes. The interior surfaces were somewhat non-spherical, with horn-like structures where the wall was thicker, most likely owing to silicon expansion as solidification finishes. This is the first report of such a “horn expansion structure” observed on a concave substrate. EDS analysis of the inner, outer, bulk and horn regions revealed variations in carbon concentration, providing clues that inform hypotheses for the order of solidification. Finally, previously produced hollow spheres of tin-lead solder, which shrinks upon solidification, have been re-examined on their inner surfaces. We discovered craters, also where the walls are thicker, whose formation mechanism appears to mirror that of the horns observed in silicon.

A Contribution to Printed Circuit Boards' Miniaturization by the Vertical Embedding of Passive Components

Abstract This study describes a novel and unconventional approach for embedding passive surface mounted device (SMD) components into printed circuit boards. Therefore, passive components whose package size is 0201 are embedded in two types of vias. On the final quality of an embedded passive component, the effects of various technological factors, including tin-lead and lead-free solder pastes, various types and dimensions of vias, various soldering techniques, and sample positions during the reflow process, have been investigated and described. The results show the impact of tin-lead solder paste and polymeric solder paste on the creation of electrical shorts in the embedding of passive components. The application of microvias for the embedding of passive components eliminates the fundamental issues, such as electrical shorts, component dislocation, and the low success rate for creating a reliable solder joint. The proposed method for miniaturizing printed circuit boards by embedding passive components in microvias was verified by experimental results. The reliability of the proposed methodology is further supported by electrical measurements. This study describes an approach suitable to printed circuit board (PCB) prototyping that makes a negligible contribution to hardware design and electronic technologies.

CFD Investigation of the Soldering Process for a Small Spherical PCM Made of Lead-tin Alloy

Unlike welding, soldering does not involve melting the work pieces. Soldering is a process in which two or more items are joined together by melting and putting a filler metal (solder) into the joint. Failure in the solder joint may make the system components lose their functions. Electrical wiring and electronic components are joined to devices and printed circuit boards using soldering. Soldering and brazing are both used in the assembly of musical instruments. Lead-tin alloy solder employed in the current investigation which has a diameter of 4 mm and a density of 11.0103 kg/m3 with continuous heat flux heating from the domain's left side and complete insulation on the other side. The melting of PCM was simulated using the ANSYS (Fluent) melting model. Three procedures were followed during the heating stage of the reflow process to perform the melting heat-transfer analysis. The simulation's results were recorded at regular intervals of 15 seconds. The results show melting rate increases as time proceeds. It is almost the same at the initial stages and increases in the middle and the end of the melting process. Heat transfer happens mostly through conduction during the first 0–30 seconds of the melting process, changing to natural convection as the material continues to heat up.

Study on the preparation process and sintering performance of doped nano-silver paste

AbstractAfter tin–lead solders are banned, the widely used electronic packaging interconnect materials are tin–silver, tin–copper, and other alloy solders. With the application of high-power devices, traditional solders can no longer meet the new requirements. Nano-silver (Ag) paste, as a new solder substitute, exhibits excellent properties, such as excellent thermal and electrical conductivity, sintering at lower temperatures, and service at high temperatures. However, many organic devices still cannot withstand this temperature, and are often not suitable for the connection of nano-Ag paste packaging materials, therefore, it is very urgent to further reduce the sintering temperature of nano-silver paste. Based on the transient liquid phase sintering technology, by doping the nano-Ag paste with the nano-tin paste with a lower melting point to make the two uniformly mix, pressureless sintering at low temperature can be realized, and a sintered joint with a connection strength greater than 20 MPa can be formed. Considering that tin is easy to be oxidized, and the core–shell material can prevent the oxidation of tin, and at the same time ensure the uniform distribution of tin in silver, the doping scheme of the core–shell structure is determined. Heterogeneous flocculation method refers to the particles with different properties of charges which attract each other and agglomerate. It is a continuous reduction method for preparing core–shell materials. This method has the advantages of mild reaction conditions and less equipment investment, so the heterogeneous flocculation method is selected to prepare Sn@Ag core–shell nano paste. And research its sintering performance and strengthening mechanism.

Impact of Gold Thickness on Interfacial Evolution and Subsequent Embrittlement of Tin–Lead Solder Joints

Impact of Gold Thickness on Interfacial Evolution and Subsequent Embrittlement of Tin–Lead Solder Joints

The impact of intermetallic compound on microstructure, mechanical characteristics, and thermal behavior of the melt-spun Bi-Ag high-temperature lead-free solder

PurposeThis study aims to study the impact of intermetallic compound on microstructure, mechanical characteristics and thermal behavior of the melt-spun Bi-Ag high-temperature lead-free solder.Design/methodology/approachIn this paper, a new group of lead-free high-temperature Pb-free solder bearing alloys with five weight percentages of different silver additions, Bi-Agx (x = 3.0, 3.5, 4.0, 4.5 and 5.0 Wt.%) have been developed by rapidly solidification processing (RSP) using melt-spun technique as a promising candidate for the replacement of conventional Sn-37Pb common solder. The effect of the addition of a small amount of Ag on the structure, microstructure, thermal and properties of Bi-Ag solder was analyzed by means of X-ray diffractometer, scanning electron microscopy, differential scanning calorimetry and Vickers hardness technique. Applying the RSP commonly results in departures from conventional microstructures, giving an improvement of grain refinement. Furthermore, the grain size of rhombohedral hexagonal phase Bi solid solution and cubic IMC Bi0.97Ag0.03 phase is refined by Ag addition. Microstructure analysis of the as soldered revealed that relatively uniform distribution, equiaxed refined grains of secondary IMC Bi0.97Ag0.03 particles about 10 µm for Bi-Ag4.5 dispersed in a Bi matrix. The addition of trace Ag led to a decrease in the solidus and liquidus temperatures of solder, meanwhile, the mushy zone is about 11.4°C and the melting of Sn-Ag4.5 solder was found to be 261.42°C which is lower compared with the Sn-Ag3 solder 263.60°C. This means that the silver additions into Bi enhance the melting point. The results indicate that an obvious change in electrical resistivity (?) at room temperature was noticed by the Ag addition. It was also observed that the Vickers microhardness (Hv) was increased with Ag increasing from 118 to 152 MPa. This study recommended the use of the Bi-Ag lead-free solder alloys for higher temperature applications.FindingsSilver content is very important for the soldering process and solder joint reliability. Based on the present investigations described in this study, several conclusions were found regarding an evaluation of microstructural and mechanical deformation behavior of various Bi-Ag solders. The effect of Ag and rapid solidification on the melting characteristics, and microstructure of Bi-Ag alloys were studied. In addition, the mechanical properties of Bi with different low silver were investigated. From the present experimental study, the following conclusions can be drawn. The addition of Ag had a marked effect on the melting temperature of the lead-free solder alloys, it decreases the melting temperature of the alloy from 263.6 to 261.42°C. Bi-Ag solders are comprised of rhombohedral Hex. Bi solid solution and cubic Ag0.97Bi0.03 IMC is formed in the Bi matrix. The alloying of Ag could refine the primary Bi phase and the Bi0.97Ag0.03 IMC. With increasing Ag content, the microstructure of the Bi-Ag gradually changes from large dimples into tiny dimple-like structures. The refinement of IMC grains was restrained after silver particles were added into the matrix. The inhibition effect on the growth of IMC grains was most conspicuous when solder was doped with Ag particles. As a result, the Vickers microhardness of the Bi-Ag lead-free solder alloys was enhanced by more than 100% ranging from 118.34 to 252.95 MPa. Bi-Ag high-temperature lead-free solders are a potential candidate for replacing the tin-lead solder (Sn-37Pb) materials which are toxic to human and the environment and has already been banned.Originality/valueThis study recommended the use of the Bi-Ag lead-free solder alloys for high-temperature applications.

Manage the environmental risks of perovskites

Manage the environmental risks of perovskites

Fine-pitch Copper Pillar Flip Chips in High Reliability Applications

Abstract To keep up with the demands for smaller antennas with increased performance and decreased costs, most next generation architectures mandate higher IC (integrated circuit) chip integration. Compared to conventional packaging configurations, advanced chip packaging technologies, such as 2.5D and 3D, offer greater chip compatibility and lower power consumption. Given these advantages, the adoption of advanced packaging is inevitable. Within advanced packaging, the copper pillar interconnect is a key enabling technology, and the next logical step. This technology offers several benefits, including improved electromigration resistance, improved electrical and thermal conductivity, simplified underbump metallization (UBM), and higher I/O (input/output) density. The fine pitches that copper pillars allow helps the technology to supersede solder bump technology, which reaches its lowest pitch around 40 microns. Finer pitches allow for a higher I/O count, which increases performance. In this work, assembly of ultra-thin MMIC (monolithic microwave integrated circuit) GaN (Gallium Nitride) fine-pitch copper pillar flip chip assemblies on high density interposers was successfully demonstrated. Using 150μm pitch copper pillar flip chip, the assembly processes for both organic PCB (printed circuit board) and silicon interposers were evaluated, with both an ENIG (Electroless Nickel Immersion Gold) and eutectic tin-lead solder pad finish evaluated. For the 2D/2.5D/3D assembly process development, a standard in-house pick and place tool was used, followed by mass solder reflow, finished with an underfill for reliability test. The interconnect robustness was determined by die pull strengths, a flux stamping investigation, and cross-sections. Complete reliability and qualification test data on GaN copper pillar flip chip 2D assembly was completed, including 700 temperature cycles and UHAST (unbiased highly accelerated temperature/humidity stress test).

Lead pipe andlead–tinsolder scale formation and structure: A conceptual model

AbstractLead–tin solder and lead service lines (LSLs) are important sources of lead, and after LSLs are removed, lead–tin solder will remain a major source of lead. A better understanding of the factors that control lead release from solder joints can help water utilities reduce lead. This paper reviews the reactions that take place at galvanic connections involving both lead–tin solder and lead pipe in contact with copper. A conceptual model based on these reactions was developed and is presented here to explain how such scale structure forms. The likely reactions that affect lead release for each of three cases, (1) no galvanic action, (2) lead anode and copper–brass cathode, and (3) lead cathode and copper–brass anode, are presented. The model also considers uniform corrosion that takes place on LSLs. This model should be useful when evaluating the impact of water quality changes on lead release from galvanic connections and LSLs.Article Impact StatementThe conceptual model sets the basis for water systems to anticipate the impact of water quality changes on lead release from lead surfaces.

Cost-Effective Surface-Mount Off-Center-Fed Dipole Antenna Element and Its Array for 5G Millimeter Wave New Radio Applications

A cost-effective ball grid array (BGA) packaged surface-mount off-center-fed dipole antenna element and its array are proposed for 5G millimeter-wave new radio (NR) applications. The proposed antenna element exhibits a compact size of 0.61 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.61 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.16 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ( λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength in free space at the center operating frequency) and is realized by only one FR4 layer to minimize cost. Plated through holes (PTHs) connect the dipole patch on the top layer to the bottom layer. Furthermore, tin-lead solder balls are mounted under the bottom layer to form the BGA packaging. The surface-mountable feature enables the antenna element to be integrated with other surface mount devices without any waveguide or coaxial connectors. The evaluation board uses a 50- Ω grounded coplanar waveguide (GCPW) line to test the performance of the antenna element and array. The antenna prototype and evaluation board have been manufactured and measured. The measurement results show that the -10-dB impedance bandwidth of the proposed antenna element achieves 35.7% in the range of 25.1-36 GHz. The measured peak gains of the antenna element and the 1 ×8 arrays are 6.72 and 13.53 dBi, respectively.

EFFECT OF GAMMA RADIATION ON MICROMECHANICAL BEHAVIOR OF SNPB SOLDER ALLOY

Tin-lead (SNPB) alloys are widely used in microelectronic packaging industry. It serves as a connector that provide the conductive path needed to achieve the connection from one circuit element to another circuit element. In this research, the effect of gamma irradiation on the micromechanical behaviour of tin-lead (SNPB) solder alloy has been investigated using the nano-indentation testing. Gamma radiation with a Cobalt-60 source were exposed to SNPB solders with different doses from 5 Gy to 500 Gy. In this study, the nano-indentation technique was used to understand the evolution of micromechanical properties (hardness and reduced modulus) of SNPB solder joints subjected to gamma irradiation. The results showed that the hardness of the SNPB alloys was enhanced with increasing of gamma radiation. The hardness was greatest at dose of 500 Gy of sample, 25.6 MPa and had the lowest value at un-irradiated sample. However, the reduced modulus was decreased by increasing the irradiation of gamma due to the intrinsic properties and the atomic bonding of the material.

Impact of the constitutive behaviour of the encapsulant on thermo-mechanical damage in (c-Si) solar PV modules under thermal cycling

The damage mechanism of encapsulant in solar cells with both lead-free and tin-lead solder as interconnecting material is examined by numerical investigation using finite element analysis (FEA). The magnitude of the damage was evaluated to determine the impact of different constitutive models of the encapsulant. Three different constitutive models of the EVA encapsulant namely: linear elastic material model (LEMM), temperature-dependant linear elastic material model (TDEMM) and linear viscoelastic material model (LVMM) were presented for the study. A test region average (TRA) thermal cycle generated from the in-situ climatic condition was used as the thermal load and boundary conditions for the study.Results from the numerical study show that the constitutive behaviour of the encapsulant has a significant impact on equivalent von-Mises stress and maximum principal strains in the encapsulant. The results of Equivalent von-Mises stress show a very high value of 4.857×107 Pa in the EVA material using LEMM whereas the lowest equivalent stress value of 525.83 Pa was registered in the EVA material when LVMM was used. Furthermore, life of the soldered joint from accumulated creep energy density (ACED) using LVMM of the EVA material yielded 23.4 years for the PbSn soldered interconnection. A result which correlates with reported field studies. This research proposes the LVMM as the most appropriate material constitutive model for modelling EVA encapsulant. The systematic technique employed in this study would be useful to the thermo-mechanical reliability research community and PV design and manufacturing engineers in the determination of accurate constitutive material model for robust thermo-mechanical analysis of solar PV modules.