Packaging Parameter Analysis on Solder Joint Reliability for Twin Die Stacked Packages by Variance in Strain Energy Density of Each Solder Joint

Author(s):  
Chao-yang Mao ◽  
Rong-sheng Chen
2021 ◽  
Vol 343 ◽  
pp. 02005
Author(s):  
Ramiro Sebastian Vargas Cruz ◽  
Viktor Gonda

Parallel to the development of new lead-free solders, electronic packaging has gone through a considerable evolution. A redistribution of layers allows the increase of functionality by increasing the number of inputs/outputsin the packagewhile reducing the size. The reliability of the package is strongly influenced by the reliability of the interconnects. During production and service life, there are thermal processes involved that may lead to thermal fatigue. In this work, a two-dimensional finite elementmodel of a Fan-Out Wafer Level Packaging (FO-WLP) was built, and simulations of thermal test cycles were carried out varying the solder interconnect material: SAC305, SACQ, SACR, orInnoLot. A thermal oscillating load from –40°C to 125°C was applied to the packaging for three hours.State of the art concerning solder joint reliability models based on creep behavior reveals the benefit of using energy-based parameters, as cycles to failure are inversely proportional to the average creep strain energy density.Based on theaverage creep strain energy density simulation results, the reliability of the package withdifferent solderswas compared.The qualitative results suggestthat SACQ has a significant advantage in the operational lifetime compared toSACR, InnoLot, and SAC305.


Author(s):  
Chia-Lung Chang ◽  
Tzu-Jen Lin ◽  
Chih-Hao Lai

Nonlinear finite element analysis was performed to predict the thermal fatigue for leadless solder joint of TFBGA Package under accelerated TCT (Temperature Cycling Test). The solder joint was subjected to the inelastic strain that was generated during TCT due to the thermal expansion mismatch between the package and PCB. The solder was modeled with elastic-plastic-creep property to simulate the inelastic deformation under TCT. The creep strain rate of solder was described by double power law. The furthest solder away from the package center induced the highest strain during TCT was considered as the critical solder ball to be most likely damaged. The effects of solder meshing on the damage parameters of inelastic strain range, accumulated creep strain and creep strain energy density were compared to assure the accuracy of the simulation. The life prediction equation based on the accumulated creep strain and creep strain energy density proposed by Syed was used to predict the thermal fatigue life in this study. The agreement between the prediction life and experimental mean life is within 25 per cent. The effect of die thickness and material properties of substrate on the life of solder was also discussed.


2000 ◽  
Vol 122 (4) ◽  
pp. 311-316 ◽  
Author(s):  
John H. Lau ◽  
S.-W. Ricky Lee ◽  
Chris Chang

A novel and reliable wafer level chip scale package (WLCSP) is investigated in this paper. It consists of a copper conductor layer and two low cost dielectric layers. The bump geometry consists of the eutectic solder, the copper core, and the under bump metallurgy. Nonlinear time-temperature-dependent finite element analyses are performed to determine the shear stress, shear creep strain, shear stress and shear creep strain hysteresis loops, and creep strain energy density of the corner solder joint. The thermal-fatigue life of the corner solder joint is then predicted by the averaged creep strain energy density range per cycle and a linear fatigue crack growth rate theory. The WLCSP solder bumps are also subjected to shear test. Finally, the WLCSP solder joints are subjected to both mechanical shear and thermal cycling tests. [S1043-7398(00)01004-5]


2020 ◽  
Vol 28 ◽  
pp. 734-742
Author(s):  
Pietro Foti ◽  
Seyed Mohammad Javad Razavi ◽  
Liviu Marsavina ◽  
Filippo Berto

2021 ◽  
Vol 230 ◽  
pp. 111716
Author(s):  
Pietro Foti ◽  
Seyed Mohammad Javad Razavi ◽  
Majid Reza Ayatollahi ◽  
Liviu Marsavina ◽  
Filippo Berto

Author(s):  
Mircea Bîrsan

AbstractIn this paper, we present a general method to derive the explicit constitutive relations for isotropic elastic 6-parameter shells made from a Cosserat material. The dimensional reduction procedure extends the methods of the classical shell theory to the case of Cosserat shells. Starting from the three-dimensional Cosserat parent model, we perform the integration over the thickness and obtain a consistent shell model of order $$ O(h^5) $$ O ( h 5 ) with respect to the shell thickness h. We derive the explicit form of the strain energy density for 6-parameter (Cosserat) shells, in which the constitutive coefficients are expressed in terms of the three-dimensional elasticity constants and depend on the initial curvature of the shell. The obtained form of the shell strain energy density is compared with other previous variants from the literature, and the advantages of our constitutive model are discussed.


Sign in / Sign up

Export Citation Format

Share Document