A New Thermal-Fatigue Life Prediction Model for Wafer Level Chip Scale Package (WLCSP) Solder Joints

2002 ◽  
Vol 124 (3) ◽  
pp. 212-220 ◽  
Author(s):  
John H. Lau ◽  
Stephen H. Pan ◽  
Chris Chang
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Time Dependent ◽  
Circuit Board ◽  
Wafer Level ◽  
Temperature Dependent ◽  
Thermal Fatigue Life ◽  
Chip Scale Package

A new empirical equation for predicting the thermal-fatigue life of wafer level chip scale package (WLCSP) solder joints on printed circuit board (PCB) is presented. The solder joints are subjected to thermal cycling and their crack lengths at different thermal cycles are measured. Also, the average strain energy density around the crack tip of different crack lengths in the corner solder joint is determined by a time-dependent nonlinear fracture mechanics with finite element method. The solder is assumed to be a temperature-dependent elastic-plastic and a time-dependent creep material.

A New Thermal-Fatigue Life Prediction Model for Wafer Level Chip Scale Package (WLCSP) Solder Joints

2000 ◽  
Author(s):  
John H. Lau ◽  
Stephen H. Pan ◽  
Chris Chang
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Time Dependent ◽  
Circuit Board ◽  
Wafer Level ◽  
Temperature Dependent ◽  
Thermal Fatigue Life ◽  
Chip Scale Package

Abstract A new empirical equation for predicting the thermal-fatigue life of wafer level chip scale package (WLCSP) solder joints on printed circuit board (PCB) is presented. The solder joints are subjected to thermal cycling and their crack lengths at different thermal cycles are measured. Also, the average strain energy density around the crack tip of different crack lengths in the corner solder joint is determined by a time-dependent nonlinear fracture mechanics with finite element method. The solder is assumed to be a temperature-dependent elastic-plastic and a time-dependent creep material.

scholarly journals Sporadic Early Life Solder Ball Detachment Effects on Subsequent Microstructure Evolution and Fatigue of Solder Joints in Wafer-Level Chip-Scale Packages

2020 ◽  
Vol 17 (1) ◽  
pp. 13-22
Author(s):  
Simon Schambeck ◽  
Matthias Hutter ◽  
Johannes Jaeschke ◽  
Andrea Deutinger ◽  
Martin Schneider-Ramelow
Keyword(s):  
Thermal Loading ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Temperature Cycling ◽  
Circuit Board ◽  
Automotive Electronics ◽  
Wafer Level ◽  
Aging Effects ◽  
Chip Scale Package ◽  
Solder Balls

Abstract The combination of continuous miniaturization of electronics and the demanding reliability requirements for industrial and automotive electronics is one big challenge for emerging packaging technology. One aspect is to increase the understanding of the damage under environmental loading. Therefore, the solder joints of a wafer-level chip-scale package assembled on a printed circuit board (PCB) have been analyzed after a temperature cycling test. In the case of the investigated package, a limited number of joints did not form a proper mechanical connection with the PCB copper pad. Although not intended in the first place, these circumstances cause a detachment of those joints within the first few thermal cycles. However, this constellation offers a unique opportunity to compare the solder joint microstructure after thermomechanical loading (connected joints) with pure thermal loading (detached joints) located directly next to each other. It is shown that microstructure aging effects can be directly linked to regions in the joint with increased loading. This is particularly the case for detached joints, which could almost retain their initial microstructure up to the effect of the high-temperature part of the thermal profile. By means of finite element simulation, it is further possible to quantify the increased loading on adjacent joints if isolated solder balls detach from the board. In one case presented, the lifetime of the corner joint was calculated to reduce up to 85% only.

The Assessment of Influence of the Design Factors on the Reliability of BGA Solder Joints

2005 ◽  
Vol 297-300 ◽  
pp. 1822-1827 ◽  
Author(s):  
Jae Chul Jin ◽  
Qiang Yu ◽  
Tadahiro Shibutani ◽  
Hirokazu Abe ◽  
Masaki Shiratori
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Design Stage ◽  
Concept Design ◽  
Design Engineers ◽  
Thermal Fatigue Life ◽  
Almost All ◽  
Design Factors

In recent years, package downsizing has become one of biggest trends in packaging technologies because of miniaturization and the high integration of electronic devices. As a result, the reliability of fatigue life has been prioritized as an important concern, since the thermal expansion difference between a package and printed circuit board causes thermal fatigue. But, the reliability of thermal fatigue life may be lowered by the dispersion of design factors such as the dimensions, shapes, and material properties of package systems. Also, the fracture modes (fatigue fracture, brittle destruction in the interface, and compound destruction, and so on) will be affected by these dispersion factors. Although this dispersion should be reduced in order to improve the reliability, reducing all dispersion is inefficient and time-consuming. So, the factors that greatly contribute to thermal fatigue life have to be reduced. In this study, evaluations of the influence of various design factors on the reliability of soldered joints of a BGA (Ball Grid Array) were carried out, and got each influence. With the results, design engineers can rate each factor’s effect on reliability and assess the reliability of their design beginning at the concept design stage. Consequently, it will be possible to avoid almost all reliability problems from the beginning. Also, by rating the factors, the design period can be shortened

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