Determination of Anand Parameters From Creep Testing of SAC305 Solder Joints

2020 ◽  
Author(s):  
Mohammad Ashraful Haq ◽  
Mohd Aminul Hoque ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Solder Joint ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Creep Testing ◽  
Response Curves ◽  
Sac305 Solder ◽  
Wide Range ◽  
Stress Levels ◽  
Creep Measurements ◽  
Solder Joint Fatigue

Abstract Solder Joints are among the most vulnerable components within electronic packages, and solder joint fatigue is regarded to be one of the major methods of electronic package failure. The prediction of solder joint reliability is thus of great importance and most finite element packages utilize the Anand Viscoplastic Model to model the mechanical behavior of the solder joint material. In this work, 3 × 3 arrays of SAC305 solder joints of roughly 750 μm in diameter were reflowed in between two FR-4 printed circuit boards to create a sandwich structural sample. These samples were then subjected to creep testing in shear at various temperatures (T = 25, 50, 75, 100 °C) and stress levels (τ = 5, 10, and 15 MPa). A set of specially designed fixtures was used to grip the solder joint specimens. The nine Anand model constants were then extracted from the creep data. The Anand model predicted creep response curves were then compared with the experimental creep measurements to determine the accuracy of the model. The Anand model predictions were found to match the measured data very well over a wide range of temperatures and stress levels.

Determination of Anand Parameters From Creep Testing of Sac305 Solder Joints

2021 ◽  
Author(s):  
Mohammad Ashraful Haq ◽  
Mohd Aminul Hoque ◽  
Jeffrey Suhling ◽  
Pradeep Lall
Keyword(s):  
Solder Joints ◽  
Creep Testing ◽  
Sac305 Solder

Influence of the Applied Load on the Creep Behaviour of Tin-Silver-Copper Solder

2019 ◽  
Author(s):  
Delfim F. Soares ◽  
Pedro E. Ribeiro ◽  
Pauline Capela ◽  
Daniel A. Barros ◽  
Maria F. Cerqueira ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Applied Load ◽  
Printed Circuit Boards ◽  
Creep Behaviour ◽  
Creep Tests ◽  
Dislocation Glide ◽  
Pcb Assembly ◽  
Creep Mechanisms ◽  
Solder Joint Fatigue

Abstract During the life cycle of an electronic printed circuit boards (PCBs), the cold solder joints formation between the component and PCB are a failure mode that happen commonly. This phenomenon is related to solder joint fatigue and is attributed mainly to the mismatch of the coefficients of thermal expansion (CTE) of component-solder-PCB assembly. With today’s solder joint thickness decreasing and increasing working temperatures, among others, the stresses and strains due to temperature changes are growing, leading to limited fatigue life of the products. In this way, once as fatigue life decreases with increasing plastic strain, it is important to study creep occurrence, especially during thermal cycles. In this work, a dynamic mechanical analyser (DMA) was used to study the influence of different applied load and temperature on the creep behaviour of the solder during a sequence of cycles. For these tests, different SAC405 alloy samples were produced, all in the same processing conditions. Creep tests were made on three-point-bending clamp configuration, isothermally at 303, 323 and 348 K, under three separate applied load of 3, 5 and 9 MPa. The results show that creep rate has an important decrease from the 1st to the following applied creep cycles. This behaviour occurs for all the tested loads and temperatures. Results, also, show that the main creep mechanisms changes, from a diffusion base type, for low load and different temperatures, to a dislocation glide-climb type for an applied load of 9 MPa and temperatures from 303 to 348 K. Experimental determined n exponent for the tested conditions allows the correlation between creep mechanisms and experimental parameters (applied load and temperature).

scholarly journals Influence of the Microstructure on the Creep Behaviour of Tin-Silver-Copper Solder

2018 ◽  
Author(s):  
Pedro E. Ribeiro ◽  
Delfim F. Soares ◽  
Maria F. Cerqueira ◽  
Senhorinha F. Teixeira ◽  
Daniel A. Barros ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Cooling Rate ◽  
Printed Circuit Boards ◽  
Creep Behaviour ◽  
Creep Tests ◽  
Cooling Rates ◽  
Pcb Assembly ◽  
Solder Joint Fatigue ◽  
Tin Silver Copper

A common failure mode of electronic printed circuit boards (PCB’s) is the appearance of cold solder joints between the component and PCB, during product life. This phenomenon is related to solder joint fatigue and is attributed mainly to the mismatch of the coefficients of thermal expansion (CTE) of component-solder-PCB assembly. With today’s solder joint thickness decreasing and increasing working temperatures, among others, the stresses and strains due to temperature changes are growing, leading to limited fatigue life of the products. As fatigue life decreases with increasing plastic strain, creep occurrence should have significant impact, especially during thermal cycles and, thus, should be studied. Through the cooling phase, on the production of PCB assembly’s by the reflow technology, the hoven atmosphere temperature is adjusted in order to control the cooling rate. Narrow criteria is used so as to control the inter-metallic compounds (IMC) thickness, PCB assembly distortion and defects due to thermal shock. The cooling rate also affects solder microstructure, which has direct impact on creep behaviour and, thus, on the soldered joint reliability. In this paper, a dynamic mechanical analyser (DMA) is used to study the influence of the solder cooling rate on its creep behaviour. SAC405 samples with two distinct cooling rates were produced: inside a hoven cooling and by water quenching. Creep tests were made on three-point-bending clamp configuration, isothermally at 25 °C, 50 °C and 75 °C and under three separate levels of stress, 3, 5 and 9 MPa. The results show that creep behaviour has a noticeable cooling rate dependence. It was also noticed that creep propensity is exacerbated by the temperature at which stresses are applied, especially for the slower cooling rates. Creep mechanisms were related to the solder microstructural constituents, namely by the amount of phases ant their morphology.

scholarly journals Mechanical Properties and Interface Microstructure of SAC305 Solder Joints Made to a Ag-Pd-Pt Thick Film Metallization: Part 2—Isothermal Aging Effects

2021 ◽  
Vol 18 (3) ◽  
pp. 97-112
Author(s):  
Paul. T. Vianco ◽  
Alice. C. Kilgo ◽  
Bonnie. B. McKenzie ◽  
Shelley Williams ◽  
Robert Ferrizz ◽  
...  
Keyword(s):  
Solder Joint ◽  
Thick Film ◽  
Precipitation Hardening ◽  
Failure Modes ◽  
Solder Joints ◽  
Accelerated Aging ◽  
Process Window ◽  
Aging Effects ◽  
Sac305 Solder ◽  
Hardening Mechanism

Abstract The performance and reliability were documented for solder joints made between the 96.5Sn-3.0Ag-0.5Cu (wt.%, abbreviated SAC305) Pb-free solder and a Ag-Pd-Pt thick film conductor on an alumina substrate. The Sheppard’s hook pull test was used to assess the solder joint strength. The Part 1 study confirmed that the solder joint fabrication process had a wide process window. The current study determined that the SAC305 solder joints maintained that robustness after accelerated aging at temperatures of 70–205°C and time durations of 5–200 d. Short-term aging of 5–10 d caused a peak in the pull strength peak that resulted from precipitation hardening by Ag-Pd and (Pd, Pt)xSny intermetallic compound (IMC) particles. The pull strengths did not decrease significantly after longer aging times at 70°C and 100°C; those conditions were accelerations of typical service lifetimes. Longer aging times at temperatures of 135–205°C resulted in a gradual, albeit not catastrophic, strength decrease when the precipitation hardening mechanism was lost to dissolution of the particle phases and their reprecipitation at the solder/alumina interface. The failure modes were ductile fracture in the solder except for the most severe aging conditions. These findings confirmed that the SAC305 solder/Ag-Pd-Pt thick film interconnections have excellent long-term reliability for hybrid microcircuit and high-temperature electronics applications.

Performance of 96.5Sn–3Ag–0.5Cu/fullerene composite solder under isothermal ageing and high-current stressing

2020 ◽  
Vol 33 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Guang Chen ◽  
Xinzhan Cui ◽  
Yaofeng Wu ◽  
Wei Li ◽  
Fengshun Wu
Keyword(s):  
Solder Joint ◽  
Composite Solder ◽  
Solder Joints ◽  
Experimental Results ◽  
High Current ◽  
Sac305 Solder ◽  
Content Type ◽  
Interfacial Imcs ◽  
Current Stressing ◽  
Isothermal Ageing

Purpose The purpose of this paper is to investigate the effect of fullerene (FNS) reinforcements on the microstructure and mechanical properties of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder joints under isothermal ageing and electrical-migration (EM) stressing. Design/methodology/approach In this paper, SAC305 solder alloy doped with 0.1 Wt.% FNS was prepared via the powder metallurgy method. A sandwich-like sample and a U-shaped sample were designed and prepared to conduct an isothermal ageing test and an EM test. The isothermal ageing test was implemented under vacuum atmosphere at 150°C, whereas the EM experiment was carried out with a current density of 1.5 × 104 A/cm2. The microstructural and mechanical evolutions of both plain and composite solder joints after thermal ageing and EM stressing were comparatively studied. Findings A growth of Ag3Sn intermetallic compounds (IMCs) in solder matrix and Cu-Sn interfacial IMCs in composite solder joints was notably suppressed under isothermal ageing condition, whereas the hardness and shear strength of composite solder joints significantly outperformed those of non-reinforced solder joints throughout the ageing period. The EM experimental results showed that for the SAC305 solder, the interfacial IMCs formulated a protrusion at the anode after 360 h of EM stressing, whereas the surface of the composite solder joint was relatively smooth. During the stressing period, the interfacial IMC on the anode side of the plain SAC305 solder showed a continuous increasing trend, whereas the IMC at the cathode presented a decreasing trend for its thickness as the stressing time increased; after 360 h of stressing, some cracks and voids had formed on the cathode side. For the SAC305/FNS composite solder, a continuous increase in the thickness of the interfacial IMC was found on both the anode and cathode sides; the growth rate of the interfacial IMC at the anode was higher than that at the cathode. The nanoindentation results showed that the hardness of the SAC305 solder joint presented a gradient distribution after EM stressing, whereas the hardness data showed a relatively homogeneous distribution in the SAC305/FNS solder joint. Originality/value The experimental results showed that the FNS reinforcement could effectively mitigate the failure risk in solder joints under isothermal ageing and high-current stressing. Specifically, the FNS particles in solder joints can work as a barrier to suppress the diffusion and migration of Sn and Cu atoms. In addition, the nanoidentation results also indicated that the addition of the FNS reinforcement was very helpful in maintaining the mechanical stability of the solder joint. These findings have provided a theoretical and experimental basis for the practical application of this novel composite solder with high-current densities.

The study on reliability of Ni-coated graphene doped SAC305 lead-free composite solders under high current-density stressing

2019 ◽  
Vol 31 (4) ◽  
pp. 261-270
Author(s):  
Guang Chen ◽  
Jiqiang Li ◽  
Xinwen Kuang ◽  
Yaofeng Wu ◽  
Fengshun Wu
Keyword(s):  
Solder Joint ◽  
Current Density ◽  
Composite Solder ◽  
Solder Joints ◽  
Experimental Results ◽  
Lead Free ◽  
Cathode Side ◽  
High Current ◽  
Sac305 Solder ◽  
Content Type

Purpose The purpose of this paper is to investigate the effect of nickel-plated graphene (Ni-GNS) on the microstructure and mechanical properties of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder joints before and after an electro-migration (EM) experiment. Design/methodology/approach In this paper, SAC305 solder alloy doped with 0.1 Wt.% Ni-GNS was prepared via the powder metallurgy method. A U-shaped sample structure was also designed and prepared to conduct an EM experiment. The EM experiment was carried out with a current density of 1.5 × 104 A/cm2. The microstructural and mechanical evolutions of both solder joints under EM stressing were comparatively studied using SEM and nanoindentation. Findings The experimental results showed that for the SAC305 solder, the interfacial intermetallic compounds (IMC) formulated a protrusion with an average height of 0.42 µm at the anode after 360 h of EM stressing; however, despite this, the surface of the composite solder joint was relatively smooth. During the stressing period, the interfacial IMC on the anode side of the plain SAC305 solder showed a continuous increasing trend, while the IMC at the cathode presented a decreasing trend for its thickness as the stressing time increased; after 360 h of stressing, some cracks and voids had formed on the cathode side. For the SAC305/ Ni-GNS composite solder, a continuous increase in the thickness of the interfacial IMC was found on both the anode and cathode side; the growth rate of the interfacial IMC at the anode was higher than that at the cathode. The nanoindentation results showed that the hardness of the SAC305 solder joint presented a gradient distribution after EM stressing, while the hardness data showed a relatively homogeneous distribution in the SAC305/ Ni-GNS solder joint. Originality/value The experimental results showed that the Ni-GNS reinforcement could effectively mitigate the EM behavior in solder joints under high current stressing. Specifically, the Ni particles that plated the graphene sheets can work as a fixing agent to suppress the diffusion and migration of Sn and Cu atoms by forming Sn-Cu-Ni IMC. In addition, the nanoidentation results also indicated that the addition of the Ni-GNS reinforcement was very helpful in maintaining the mechanical stability of the solder joint. These findings have provided a theoretical and experimental basis for the practical application of this novel composite solder with high current densities.

Reliability of Solder Joints

MRS Bulletin ◽  
1993 ◽  
Vol 18 (12) ◽  
pp. 49-54 ◽  
Author(s):  
D.R. Frear ◽  
F.G. Yost
Keyword(s):  
Solder Joint ◽  
Solder Joints ◽  
Thermal Conductance ◽  
Circuit Boards ◽  
Technological Advances ◽  
Wide Range ◽  
Reliability Of Solder Joints ◽  
Circuit Components ◽  
Electrical Components ◽  
Electronic Technologies

In early electronic technologies, circuit components were attached to circuit boards by mechanical means. The electrical leads were either twisted together or mechanically interlocked to a board prior to soldering. The possibility of an unreliable solder joint causing any kind of circuit failure was remote. Interconnections were made intrinsic to the board by applying solder to increase electrical and thermal conductance. Technological advances and the need for high-density electronics have since eliminated the luxury of mechanical interlocks. Soldering in advanced applications, like surface mount technology (SMT), provides electrical, thermal, and mechanical interconnections between the board and its electrical components. In SMT, solder joints are the only mechanical features on the board and must hold components in place in a wide range of environments. The solder joints themselves are decreasing in size as increased chip functionality and clock frequencies become available. The failure of a single solder joint can render a device, or an entire electrical system, inoperable. Therefore, as insignificant and innocuous as they may seem, solder joints have become a critical aspect of electronic circuit reliability.

Reflow of tiny 01005 capacitor/SAC305 solder joints in protective atmosphere

2017 ◽  
Vol 29 (3) ◽  
pp. 144-150 ◽  
Author(s):  
Yeqing Tao ◽  
Dongyan Ding ◽  
Ting Li ◽  
Jason Guo ◽  
Guoliang Fan
Keyword(s):  
Solder Joint ◽  
Oxygen Concentration ◽  
Solder Joints ◽  
Protective Atmosphere ◽  
Low Oxygen ◽  
Reflow Process ◽  
Sac305 Solder ◽  
Content Type ◽  
Placement Accuracy ◽  
Component Assembly

Purpose This paper aims to study the influence of reflow atmosphere and placement accuracy on the solderability of 01005 capacitor/SAC305 solder joints. Design/methodology/approach The 01005 capacitors were mounted on OSP-coated pads, and the samples were fabricated in four different atmospheres, i.e. 200 ppm O2/N2, 1,000 ppm O2/N2, 3,000 ppm O2/N2 and air. After the reflow process, visual inspection and X-ray detection were carried out to examine the solder joint shapes and possible defects. Some of the samples fabricated in different conditions were cross-sectioned and the solder joint microstructures were analyzed. On the other hand, besides placing the components on their normal pad positions, a 50 per cent offset of the x-axis (long axis) or y-axis (short axis) was introduced into the chip mounter programs to evaluate the 01005 capacitor’s assembly sensitivity to placement accuracy. The process-induced defects were investigated. Findings Experimental results indicated that an N2-based protective atmosphere was necessary for 01005 type assembly, as it could obviously improve the 01005 solder joint quality, compared with the air condition. The protective atmosphere had little effect on the appearance, quality and microstructure of solder joints when the oxygen concentration was below 3,000 ppm. But a very low oxygen concentration could increase the risk of tombstoning defects for the assembly process. The N2-based protective atmosphere containing 1,000-2000 ppm O2 was acceptable and appropriate for the assembly of tiny components. Originality/value The results of this work provide a set of reflow process parameters and recommendations for 01005 size component assembly in manufacturing.

IC solder joint inspection based on the Gaussian mixture model

2016 ◽  
Vol 28 (4) ◽  
pp. 207-214 ◽  
Author(s):  
Nian Cai ◽  
Qian Ye ◽  
Gen Liu ◽  
Han Wang ◽  
Zhijing Yang
Keyword(s):  
Solder Joint ◽  
Gaussian Mixture Model ◽  
Mixture Model ◽  
Integrated Circuit ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Gaussian Mixture ◽  
Content Type ◽  
Solder Joint Inspection ◽  
Frequency Map

Purpose This paper aims to inspect solder joint defects of integrated circuit (IC) components on printed circuit boards. Here, an IC solder joint inspection algorithm is developed based on a Gaussian mixture model (GMM). Design/methodology/approach First, the authors train a GMM using numerous qualified IC solder joints. Then, the authors compare the IC solder joint images with the trained model to inspect the potential defects. Finally, the authors introduce a frequency map and define a metric termed as normalized defect degree to evaluate qualities of the tested IC solder joints. Findings Experimental results indicate that the proposed method is superior to the state-of-the-art methods on IC solder joint inspection. Originality/value The approach is a promising method for IC solder joint inspection, which is quite different from the traditional classifier-based methods.

Inhibiting the Re-Deposition of AuSn4 on Au/Ni Metallization Pads by Varying the Accessibility of Cu in Isothermally Aged SAC305 Solder Joints

2013 ◽  
Author(s):  
Subhasis Mukherjee ◽  
Abhijit Dasgupta ◽  
Julie Silk ◽  
Lay-ling Ong
Keyword(s):  
Solid State ◽  
Solder Joint ◽  
Barrier Layer ◽  
Solder Joints ◽  
Circuit Board ◽  
Nickel Layer ◽  
Gold Content ◽  
Sac305 Solder ◽  
Lap Shear ◽  
Sac Solder

Electroplated Ni/Au over Cu is a popular metallization for printed circuit board (PCB) finish as well as for component leads, especially for wire-bondable high frequency packages, where the gold thickness (≥ 20 μinches) requirement is high for wire bonding. Redeposition of bulk AuSn4 intermetallic compound (IMC) at Au/Ni contact pads of isothermally conditioned SnAgCu (SAC) solder joints is a critical reliability concern in these packages because the interfacial layer between redeposited AuSn4 IMC and initially formed IMC during reflow at the contact pad after reflow is brittle in nature. Redeposition of bulk AuSn4 IMC in Pb-free SAC solder joints (most popularly SAC305) is also believed to be dependent on the degree of access to copper. This study examines the effect of varying gold content (2–5 nominal weight-%) in the solder joint and accessibility to copper (by presence or absence of nickel barrier layer on top of Cu plating) on redeposition of AuSn4 IMCs at the interface of isothermally aged SAC305 solder joints for 720 hours at 121°C (0.8*Tmelt). The modified lap shear Iosipescu specimens used for the study are divided into two batches: i] In the first batch, both the copper platens to be soldered are electroplated with Au and Ni. Ni barrier layers are used to completely stop the solder from accessing the Cu in the substrate ii] In the second batch, one Cu platen is electroplated with Au and Ni barrier layer but the other platen is electroplated only with copper (no Nickel layer), to allow accessibility of Cu from the substrate. Representative solder joints from above two batches are then cross-sectioned and analyzed using environmental scanning electron microscopy (ESEM) and energy-dispersive x-ray spectroscopy (EDX) to investigate the composition, thickness and morphology of both bulk and interfacial IMCs. The first phase to form at the interface of the first batch of specimens after initial reflow is Ni3Sn4/(Ni,Cu)3Sn4. During the subsequent solid-state annealing, the redeposition of AuSn4 occurred in systems plated with Au/Ni on both sides. Contrarily, in the second batch when the solder joint has copper access from one side of the joint, the first intermetallic after reflow to form is (Cu,Ni,Au)6Sn5/(Cu,Au)6Sn5 and no redeposition of AuSn4 is observed after solid state annealing except for the solder joint containing nominal 5wt-% of Au.

Sign in / Sign up

Export Citation Format

Share Document