Damage Constitutive Model and Failure Mechanism of Lead-Free Solder in CBGA Package

2008 ◽  
Vol 44-46 ◽  
pp. 77-84
Author(s):  
Wei Na Hao ◽  
Guo Zhong Chai ◽  
J. Zhou
Keyword(s):  
Constitutive Model ◽  
Thermal Loading ◽  
Mechanical Response ◽  
Failure Process ◽  
Damage Model ◽  
Lead Free ◽  
Lead Free Solder ◽  
Element Analysis ◽  
Cyclic Thermal Loading ◽  
Free Solder

A viscoplastic constitutive model with void damage is developed to analyze the macroscopic mechanical response and damage mechanism of lead-free solder alloy in CBGA packaging under cyclic thermal loading. The constitutive model is implemented into ABAQUS through its user defined material subroutine. Two-dimensional nonlinear finite element analysis of a ceramic ball grid array(CBGA) package is conducted to simulate the viscoplastic deformation and damage failure process of the lead-free solder joint under cyclic thermal loading. The damage model is helpful for optimization and reliability of electronic package.

20306 Machanical Properties of Lead-free Solder Joints under Cyclic Thermal Loading

2015 ◽  
Vol 2015.21 (0) ◽  
pp. _20306-1_-_20306-2_
Author(s):  
Takeharu HAYASHI ◽  
Hirohiko WATANABE ◽  
Yoshinori EBIHARA ◽  
Kenta ENOKI ◽  
Kento TAKADA ◽  
...  
Keyword(s):  
Thermal Loading ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Cyclic Thermal Loading ◽  
Free Solder

Time-Independent and Time-Dependent Inelastic Strain Analysis of Lead-Free Solder by Cyclic Loading Test Using Stepped Ramp Waves

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Ken-ichi Ohguchi ◽  
Katsuhiko Sasaki
Keyword(s):  
Cyclic Loading ◽  
Plastic Strain ◽  
Creep Strain ◽  
Thermal Loading ◽  
Time Dependent ◽  
Lead Free ◽  
Creep Model ◽  
Lead Free Solder ◽  
Cyclic Thermal Loading ◽  
Free Solder

We previously proposed an elastic-plastic-creep model to estimate the fatigue strength of lead-free solder joints subjected to cyclic thermal loading. The proposed model requires detailed experimental data regarding the time-independent plastic strain and the time-dependent creep strain during cyclic thermal loading. This paper proposes an experimental method for determining the characteristics of both the plastic and creep strains generated during cyclic loading that employs stepped ramp waves. This method is applied to cyclic tension-compression loadings using a Sn–3.0Ag–0.5Cu lead-free solder for several loading conditions. The method can separate between the time-independent plastic strain and the time-dependent creep strain in cyclic inelastic deformation of solder alloys.

A Practical Viscoplastic Damage Model for Lead-Free Solder

2005 ◽  
Vol 128 (1) ◽  
pp. 71-81 ◽  
Author(s):  
A. F. Fossum ◽  
P. T. Vianco ◽  
M. K. Neilsen ◽  
D. M. Pierce
Keyword(s):  
Damage Model ◽  
Constant Strain Rate ◽  
Internal Variable ◽  
Equation Model ◽  
Lead Free ◽  
Lead Free Solder ◽  
Creep Tests ◽  
Damage Evolution Equation ◽  
Cyclic Shear ◽  
Free Solder

This paper summarizes the results of a program to construct an internal variable viscoplastic damage model to characterize 95.5Sn–3.9Ag–0.6Cu (wt.%) lead-free solder under cyclic thermomechanical loading conditions. A unified model is enhanced to account for a deteriorating microstructure through the use of an isotropic damage evolution equation. Model predictions versus experimental data are given for constant strain-rate tests that were conducted at strain rates of 4.2×10−5s−1 and 8.3×10−4s−1 over a temperature range from −25°Cto160°C; cyclic shear tests; and elevated-temperature creep tests. A description is given of how this work supports larger ongoing efforts to develop a predictive capability in materials aging and reliability, and solder interconnect reliability.

Behavior of Lead-Free Solder Under Thermomechanical Loading

2004 ◽  
Vol 126 (3) ◽  
pp. 367-373 ◽  
Author(s):  
Y. Wei ◽  
C. L. Chow ◽  
K. J. Lau ◽  
P. Vianco ◽  
H. E. Fang
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Base Alloy ◽  
Back Stress ◽  
General Purpose ◽  
Lead Free ◽  
Element Analysis ◽  
Different Temperatures ◽  
Free Solder

This paper presents an investigation of lead-free Sn-Ag base alloy, 95.5Sn-3.9Ag-0.6Cu, both experimentally and analytically. Experimentally, the deformation behavior of the material was measured for different temperatures (25°C and 1000°C) over a range of strain rates (10−5 to 10−3/s) under isothermal and thermomechanical conditions. Development of a unified viscoplastic constitutive model followed, taking into account the effects of the measured strain rate and temperature changes. The temperature rate effects are considered in the evolution equation of back stress. In order to include material degradation in the solder, the theory of damage mechanics is applied by introducing two damage variables in the viscoplastic constitutive model. Finally, the constitutive model is coded into a general-purpose finite element computer program (ABAQUS) through its user-defined material subroutine (UMAT). The damage-coupled finite element analysis (FEA) is then employed to monitor the condition of failure of a notched component. The predicted and measured maximum loads have been compared and found to be satisfactory. In addition, the calculated damage distribution contours enable the identification of potential failure site for failure analysis.

Deformation Behavior of SAC305 Solder Joints With Multiple Grains

2020 ◽  
Author(s):  
Debabrata Mondal ◽  
Abdullah Fahim ◽  
KM Rafidh Hassan ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Grain Size ◽  
Solder Joint ◽  
Deformation Behavior ◽  
Thermal Loading ◽  
Solder Joints ◽  
Lead Free ◽  
External Loading ◽  
Lead Free Solder ◽  
Material Anisotropy ◽  
Free Solder

Abstract Lead-free solder joints are the most widely used interconnects in electronic packaging industries. Usually solder joints in most of the electronic devices are exposed to an environment where variation of temperature exists, which indicates cyclic thermal loading to be a very common type of external loading. Moreover, due to difference in the coefficient of thermal expansion (CTE) among dissimilar contact materials, shear stress develops in junctions under thermal loading, which significantly deteriorates the overall reliability. Hence, characterization of lead-free solder materials under thermal loading is essential to predict the performance and deformation behavior of joints in practical applications. A significant portion of the studies in this field are concerned with thermal loading of lead-free solder interconnects, each of which has a very small diameter, in sub-millimeter range. Although the solder balls have very small dimensions, most of the analyses considered them as a bulk material with homogeneous and isotropic properties. However, with the decrease of specimen dimensions, size effects and material directionality play a significant role in deformation mechanisms. Since a very few grains exist in a small specimen, individual grain properties play a vital role on overall material response. Therefore, modeling from the grain structure and orientation point of view could be an effective and more accurate way to predict solder joint deformation behavior under thermal loading. In this study, the effect of grain size and orientation of SAC305 is investigated for predicting anisotropic behavior of solder joints under thermal load. A simplified three-dimensional model of beach-ball configuration solder joint was generated and simulated using ABAQUS finite element (FE) software. Experimentally obtained directional properties such as elastic modulus and CTE were assigned to the computational geometry to create material anisotropy. The effects of material anisotropy were studied for varying grain size specimens, as well as for specimens with varying grain orientation.

scholarly journals Application of Viscoplastic-Creep Separate Constitutive Model to Lead-Free Solder Alloy

2011 ◽  
Vol 77 (780) ◽  
pp. 1169-1177 ◽  
Author(s):  
Takeharu HAYASHI ◽  
Yoshinori EBIHARA ◽  
Tatsuhiko ASAI ◽  
Hirohiko WATANABE
Keyword(s):  
Constitutive Model ◽  
Solder Alloy ◽  
Lead Free ◽  
Lead Free Solder ◽  
Lead Free Solder Alloy ◽  
Free Solder

Damage Evolution in Lead Free Solder Joints in Isothermal Fatigue

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Awni Qasaimeh ◽  
Sa’d Hamasha ◽  
Younis Jaradat ◽  
Peter Borgesen
Keyword(s):  
Crack Initiation ◽  
Mechanical Response ◽  
Solder Joints ◽  
Fatigue Testing ◽  
Hysteresis Loops ◽  
Damage Function ◽  
Lead Free ◽  
Lead Free Solder ◽  
Sac305 Solder ◽  
Free Solder

The extrapolation and generalization of accelerated test results for lead free solder joints require the identification of a damage function that can be counted on to apply beyond the region of the test. Individual ball grid array (BGA) scale Sn3Ag0.5Cu (SAC305) solder joints were subjected to isothermal shear fatigue testing at room temperature and 65 °C. The resulting mechanical response degradation and crack behavior, including strain hardening, crack initiation, and propagation, were correlated with the inelastic work and effective stiffness derived from load–displacement hysteresis loops. Crack initiation was found to scale with the accumulated work, independently of cycling amplitude and strain rate. The subsequent damage rate varied slightly with amplitude.

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