scholarly journals Fatigue Life Scatter of Lead-Free Solder Joints for Chip Components(Thermal and Mechanical Reliability of Electronic Device and Mechanical Engineering)

2009 ◽  
Vol 75 (755) ◽  
pp. 815-822
Author(s):  
Hiroki MIYAUCHI ◽  
Qiang YU ◽  
Tadahiro SHIBUTANI
Keyword(s):  
Fatigue Life ◽  
Mechanical Engineering ◽  
Solder Joints ◽  
Electronic Device ◽  
Lead Free ◽  
Lead Free Solder ◽  
Mechanical Reliability ◽  
Special Issue ◽  
Free Solder

A Study on Evaluation Technique for the Fatigue Life Scatter of Lead-Free Solder Joints

2007 ◽  
Author(s):  
Hiroki Miyauchi ◽  
Qiang Yu ◽  
Tadahiro Shibutani ◽  
Masaki Shiratori
Keyword(s):  
Fatigue Life ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Electronic Device ◽  
Electronic Devices ◽  
Lead Free ◽  
Sensitivity Analyses ◽  
Lead Free Solder ◽  
Free Solder ◽  
Design Factors

The electronic device equipments using a lot of semiconductors are widespread to all industrial fields. Solder joints are used to mount the electronic chips, such as ceramic resistors and capacitors, on the printed-circuit boards in almost all electronic devices. However, since in many cases the thermal expansion coefficients of electronic parts and PCBs have mismatch, cyclic thermal stress and strain causes solder fatigue. Especially in the power electronic module and car electric module, the evaluation of thermal fatigue life for the chip components is important. It is understood that the fatigue lives of some electronic devices show large scatter in the thermal cycle test, even if their design is the same. The dispersion of main design factors of solder joints is thought as one of these reasons. Moreover, the influence of the dispersion grows when the lead-free solder materials are used in the devices. Therefore, it cannot be bypassed as the main issue for the reliability evaluation in the solder joints. In this study, how the dispersion of design factors influences the fatigue life in lead-free solder joint was investigated by the analytical approach. At first, sensitivity analyses were carried out to study the main effect of the dispersion of each factor on solder joints. And then, the interacting effects between the factors on the reliability were studied by considering the structural asymmetry due to the unbalanced solder joints. FEM analyses were carried out, and the fatigue life in solder joints was calculated from the inelastic strain range. As a result, practical evaluating approach for the fatigue life scatter of solder joints was proposed.

Effect of Micro Structure on Fatigue Characteristics of Lead Free Solder Joints

2011 ◽  
Author(s):  
Takahiro Akutsu ◽  
Qiang Yu
Keyword(s):  
Grain Size ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Solder Joint ◽  
Crack Propagation ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Micro Structure ◽  
Free Solder

This paper presents the influence of the micro structure on the crack propagation in lead free solder joint. The author’s group have studied the Manson-Coffin’s law for lead free solder joint by using the isothermal fatigue test and FEM analytical approaches to establish the practicable evaluation of thermal fatigue life of solder joints, for example, for the Sn-Cu-Ni solder, because this solder is attracted from the aspect of the decrease of solder leach in the flow process and material cost. However, even if the same loading is given to the solder joints of BGA test piece, there was a large dispersion in the fatigue life. Even though the effect of the shape difference has been considered, the range of the dispersion could not been explained sufficiently. In the study, the fatigue crack propagation modes in the solder joints were investigated, and an internal fatigue crack mode and an interfacial fatigue crack mode were confirmed. And the tendency of a shorter on fatigue life in the interfacial fatigue mode was confirmed. To clarify the mechanism of these fatigue crack modes, the crystal grain size in the solder joints was investigated before the fatigue test and also after the test. Furthermore, the verification of the mechanism using FEM models considering the crystal grain size was carried out. First of all, each element in FEM models matching to the average crystal grain size was made. Second, the inelastic strain ranges in each FEM models were studied. As a result, it was shown that the influence of the crude density of the crystal grain to the fatigue crack progress can be evaluated. In addition, the micro structure of the solder joint of large-scale electronic devices is observed, and FEM model was made based on the observation result. As a result, it was shown that the influence of the directionality with the crystal grain to the fatigue crack progress can be evaluated.

Effect of Void on Fatigue Life of Lead-Free Solder Joints

2002 ◽  
Vol 2002 (0) ◽  
pp. 9-10
Author(s):  
Ken KAMINISHI ◽  
Yukihiro KAWAMURA ◽  
Motoharu TANEDA ◽  
Hirohide KAIDA
Keyword(s):  
Fatigue Life ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Free Solder

scholarly journals Effects of voids on thermal-mechanical reliability of lead-free solder joints

2014 ◽  
Vol 12 ◽  
pp. 04026 ◽  
Author(s):  
Lahouari Benabou ◽  
Van Nhat Le ◽  
Zhidan Sun ◽  
Philippe Pougnet ◽  
Victor Etgens
Keyword(s):  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Mechanical Reliability ◽  
Free Solder

A Study on Strain Concentration Around V Notch in Lead Free Solder Material and the Low Cycle Fatigue Life

2015 ◽  
Author(s):  
Takashi Kawakami ◽  
Takahiro Kinoshita ◽  
Hirokazu Oriyama
Keyword(s):  
Fatigue Life ◽  
Solder Joints ◽  
Low Cycle Fatigue ◽  
Lead Free ◽  
Design Rule ◽  
Lead Free Solder ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Test Pieces ◽  
Free Solder

Solder joints are sometimes opened under thermal cyclic loads as low cycle fatigue phenomena. The fatigue crack is usually initiated around the edge of the interface where stress and strain very severely concentrate, having stress strain singularity. In this study, Sn-3.0Ag-0.5Cu test pieces with V shape notch were supplied to low cycle fatigue tests at 100°C. And inelastic stress strain simulations, which were based on time-dependent non-unified material model, were carried out under several cyclic load levels to obtain strain distributions around the bottom of the V notch. By results of fatigue test and inelastic simulation, the depth from the bottom of the V notch, where the strain range agrees with the prediction of the fatigue life based on smooth test pieces on Coffin-Manson rule, was investigated as the mechanical design rule for lead free solder joints.

scholarly journals Thermal Fatigue Life Simulation for Sn-Ag-Cu Lead-Free Solder Joints

2004 ◽  
Vol 7 (4) ◽  
pp. 308-313 ◽  
Author(s):  
Hiroyuki TAKAHASHI ◽  
Takashi KAWAKAMI ◽  
Minoru MUKAI ◽  
Nobutada OHNO
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Thermal Fatigue Life ◽  
Free Solder
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