scholarly journals Creep-Fatigue Behaviours of Sn-Ag-Cu Solder Joints in Microelectronics Applications

2021 ◽  
Author(s):  
Joshua A. Depiver ◽  
Sabuj Mallik ◽  
Yiling Lu ◽  
Emeka H. Amalu
Keyword(s):  
Energy Density ◽  
Thermal Cycling ◽  
Strain Rate ◽  
Deformation Rate ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Solder Joints ◽  
Creep Fatigue ◽  
Accelerated Thermal Cycling ◽  
Isothermal Ageing

Electronic manufacturing is one of the dynamic industries in the world in terms of leading technological advancements. Electronic assembly’s heart lies the ‘soldering technology’ and the ‘solder joints’ between electronic components and substrate. During the operation of electronic products, solder joints experience harsh environmental conditions in terms of cyclic change of temperature and vibration and exposure to moisture and chemicals. Due to the cyclic application of loads and higher operational temperature, solder joints fail primarily through creep and fatigue failures. This paper presents the creep-fatigue behaviours of solder joints in a ball grid array (BGA) soldered on a printed circuit board (PCB). Using finite element (FE) simulation, the solder joints were subjected to thermal cycling and isothermal ageing. Accelerated thermal cycling (ATC) was carried out using a temperate range from 40°C to 150°C, and isothermal ageing was done at −40, 25, 75 and 150°C temperatures for 45 days (64,800 mins). The solders studied are lead-based eutectic Sn63Pb37 and lead-free SAC305, SAC387, SAC396 and SAC405. The results were analysed using the failure criterion of equivalent stress, strain rate, deformation rate, and the solders’ strain energy density. The SAC405 and SAC396 have the least stress magnitude, strain rate, deformation rate, and strain energy density damage than the lead-based eutectic Sn63Pb37 solder; they have the highest fatigue lives based on the damage mechanisms. This research provides a technique for determining the preventive maintenance time of BGA components in mission-critical systems. Furthermore, it proposes developing a new life prediction model based on a combination of the damage parameters for improved prediction.

Critical Accumulated Strain Energy (Case) Failure Criterion for Thermal Cycling Fatigue of Solder Joints

1994 ◽  
Vol 116 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Tsung-Yu Pan
Keyword(s):  
Fatigue Life ◽  
Energy Density ◽  
Thermal Cycling ◽  
Creep Strain ◽  
Failure Criterion ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Solder Joints ◽  
Field Service ◽  
Accumulated Strain

In the automotive and computer industries, a perennial challenge has been to design an adequate and efficient accelerated thermal cycling test which would correspond to field service conditions. Failures, induced in both thermal cycle testing and field service, are characterized by thermal fatigue behavior. Several fatigue models have been proposed, none of these models take into account all of the many parameters of the test or service environment. In thermal cycling, for example, the temperature range, ramp rate, hold time, and stepped heating and cooling are known to influence the number of cycles to failure. In this study, a critical accumulated strain energy (CASE) failure criterion is proposed to correlate the fatigue life to both the plastic and creep strain energies, which accumulate in solder joints during the thermal cycling. This criterion suggests that solder joints fail as the strain energy accumulates and reaches a critical value. By using finite element analysis with a “ladder” procedure, both time-independent plastic strain energy and time-dependent creep strain energy are quantified. These are related to fatigue life by the equation: C = N*f (Ep + 0.13Ec), where C is the critical strain energy density, Nf is the fatigue life, Ep and Ec are plastic and creep strain energy density accumulation per cycle, respectively, for the eutectic Sn-Pb solders. By analyzing Hall and Sherry’s thermal cycling data (Hall and Sherry, 1986), it is found that creep is the predominant factor in deciding fatigue life. Creep accounts for 51 to 97 percent of the total accumulated strain energy, depending on the cycling profiles. This criterion is used to simulate crack propagation in a solder joint by analyzing the strain energy in small “domains” within the joint.

scholarly journals IMPACT TESTING OF ORDNANCE GELATINE UNDER MODERATE STRAIN RATE CONDITIONS

2018 ◽  
Vol 18 ◽  
pp. 44
Author(s):  
Tomáš Doktor ◽  
Petr Zlámal ◽  
Jan Šleichrt ◽  
Tomáš Fíla ◽  
Daniel Kytýř
Keyword(s):  
Energy Density ◽  
Strain Rate ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Deformation Behaviour ◽  
Rate Sensitivity ◽  
Impact Testing ◽  
Static Compression ◽  
Static Conditions ◽  
The Impact

An experimental study on energy absorption capabilities and strain rate sensitivity of ordnance gelatine was performed. Strain energy density under quasi static compression and moderate strain rate impact tests was compared. In the study two types of material were tested, bulk ordnance gelatine and polymeric open-cell meshwork filled with ordnance gelatine. From the results a significant strain-rate effect was observed in terms of ultimate compressive strength and strain energy density. In comparison of the deformation behaviour under quasi static conditions and drop weight test the difference was very significant, however slight increase in both strength and strain energy density was observed even between different impact energies and velocities during the impact testing. The peak acceleration was significantly reduced in polymer meshwork filled by gelatine in comparison to the bulk gelatine.

An Innovative Yield Criterion Considering Strain Rates Based on Von Mises Stress

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Jingwei Yu ◽  
Qingguo Fei ◽  
Peiwei Zhang ◽  
Yanbin Li ◽  
Dahai Zhang ◽  
...  
Keyword(s):  
Energy Density ◽  
Yield Strength ◽  
Constitutive Model ◽  
Strain Rate ◽  
Dynamic Load ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Yield Criterion ◽  
Von Mises Stress ◽  
Von Mises

Abstract An innovative yield criterion based on von Mises stress is proposed to represent the strain rate-dependent behavior under dynamic load. Considering the strain rate in the constitutive model, the distortional strain energy density is derived and the yield criterion is established. A plot of yield strength for a range of strain rate reveals that despite the differences in material properties and test methods, the yield strength rise can be represented by a unified criterion. The overall yield behavior of the material under dynamic load can be explained by introducing the strain rate into the constitutive model and threshold distortional strain energy density. This criterion is in a simple form that may be widely applied.

scholarly journals Experimental SAC305 Shear Stress–Strain Hysteresis Loop Construction Using Hall's One-Dimensional Model Based on Strain Gages Measurements

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
J.-B. Libot ◽  
J. Alexis ◽  
O. Dalverny ◽  
L. Arnaud ◽  
P. Milesi ◽  
...  
Keyword(s):  
Shear Stress ◽  
Energy Density ◽  
Hysteresis Loop ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Solder Joints ◽  
Strain Gages ◽  
Sac305 Solder ◽  
Stress Strain ◽  
Temperature Cycles

Temperature-induced solder joint fatigue is a main reliability concern for aerospace and military industries whose electronic equipment used in the field is required to remain functional under harsh loadings. Due to the RoHS directive, which eventually will prevent lead from being utilized in electronic systems, there is a need for a better understanding of lead-free thermomechanical behavior when subjected to temperature variations. Characterizing solder joints properties remains a challenge as viscoplastic behavior during thermal cycling is complex, and their small dimensions prevent direct measurements from being performed. This paper reports the experimentation based on strain gage measurements, allowing the construction of the shear stress–strain hysteresis loop corresponding to Sn3.0Ag0.5Cu (SAC305) solder joints behavior during thermomechanical loading. This methodology, initially developed in 1984 by Hall for Sn60Pb40 interconnects, allows the measurement of the strain energy density dissipated during temperature cycles. Custom daisy-chained 76 I/O ceramic ball grid array (CBGA76) components were designed and assembled on flame retardant (FR-4) multilayered printed circuit boards (PCB). Four strain gages were specifically placed at the center of the assembly on top and bottom faces of both PCB and CBGA76 component. The assembly was subjected to temperature cycles and the SAC305 solder joints shear stress–strain hysteresis loop was plotted. The correlation between the measured strain energy density and measured lifetime corresponds to one point of the energy based fatigue curve for SAC305 solder joints. The hysteresis loop also provides the necessary data to derive SAC305 solder joints constitutive laws.

A modified strain energy density exhaustion model for creep–fatigue life prediction

2016 ◽  
Vol 90 ◽  
pp. 12-22 ◽  
Author(s):  
Run-Zi Wang ◽  
Xian-Cheng Zhang ◽  
Shan-Tung Tu ◽  
Shun-Peng Zhu ◽  
Cheng-Cheng Zhang
Keyword(s):  
Fatigue Life ◽  
Energy Density ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Creep Fatigue

Strain Energy Density Criterion for Reliability Life Prediction of Solder Joints in Electronic Packaging

2004 ◽  
Vol 126 (3) ◽  
pp. 398-405 ◽  
Author(s):  
I. Guven ◽  
V. Kradinov ◽  
J. L. Tor ◽  
E. Madenci
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Energy Density ◽  
Crack Growth ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Life Prediction ◽  
Solder Joints ◽  
Intrinsic Property ◽  
Electronic Packages

This study concerns the prediction of crack growth rate for solder joints in electronic packages under thermal cycling. The crack growth rate, which is dependent on the intrinsic solder property and the current stress state, is calculated based on the strain energy density criterion. The critical value of the strain energy density represents the intrinsic property of the solder. The comparison of the crack growth predictions with the experimental measurements demonstrates the applicability of the strain energy density criterion for the reliability life prediction of solder joints.

scholarly journals A New 3D Creep-Fatigue-Elasticity Damage Interaction Diagram Based on the Total Tensile Strain Energy Density Model

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 274 ◽  
Author(s):  
Qiang Wang ◽  
Naiqiang Zhang ◽  
Xishu Wang
Keyword(s):  
High Temperature ◽  
Energy Density ◽  
Fatigue Damage ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Life Prediction ◽  
Tensile Strain ◽  
Elastic Strain Energy ◽  
Interaction Diagram ◽  
Creep Fatigue

Fatigue damage, creep damage, and their interactions are the critical factors in degrading the integrity of most high-temperature engineering structures. A reliable creep-fatigue damage interaction diagram is a crucial issue for the design and assessment of high-temperature components used in power plants. In this paper, a new three-dimensional creep-fatigue-elasticity damage interaction diagram was constructed based on a developed life prediction model for both high-temperature fatigue and creep fatigue. The total tensile strain energy density concept is adopted as a damage parameter for life prediction by using the elastic strain energy density and mean stress concepts. The model was validated by a great deal of data such as P91 steel at 550 °C, Haynes 230 at 850 °C, Alloy 617 at 850 and 950 °C, and Inconel 625 at 815 °C. The estimation values have very high accuracy since nearly all the test data fell into the scatter band of 2.0.

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