Temperature cycling reliability test for a ball grid array (BGA) package using finite element analysis (FEA)
Thermal cycling test is one of the reliability test that has been used to evaluate the reliability of the solder joint interconnect in ball grid array (BGA) package. The purpose of thermal cycling test is to characterize thermomechanical failure mechanism on microelectronics package. This research...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Universiti Malaysia Perlis
2010
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| Subjects: | |
| Online Access: | http://dspace.unimap.edu.my/xmlui/handle/123456789/9878 |
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| Summary: | Thermal cycling test is one of the reliability test that has been used to evaluate the reliability of the
solder joint interconnect in ball grid array (BGA) package. The purpose of thermal cycling test is to
characterize thermomechanical failure mechanism on microelectronics package. This research utilizes the
computer capability to run the thermal cycling test by using finite element analysis (FEA). FEA of thermal
cycling test is done by using ANSYS™ finite element software. Quarter symmetry BGA package model is
built parametrically by using APDL (ANSYS™ Parametric Design Language and Macros). Two types of
analyses are used to evaluate the reliability performance of solder joints in BGA package, namely the physics
based analysis and the statistical based analysis. Darveaux’s energy based fatigue model is used as the
constitutive equation for solder. One of the temperature cycling conditions namely, G based on JEDEC
JESD22-A104 standard is used throughout the finite element analysis. The effect of different temperature
cycling condition is studied by applying different value of dwell times and ramp rates. Two screening design
methods namely, Central Composite Design (CCD) and Box-Behnken Matrix Design method are used to
isolate the most important factors amongst six design variables such as solder joint standoff height, printed
circuited board (PCB) core thickness, PCB core-in-plane Young’s Modulus, PCB core-in-plane coefficient of
thermal expansion (CTE), die thickness and mold compound thickness. The optimization process is carried
out using response surface methodology (RSM) to predict appropriate variables or factors that have a
significant influence on BGA package failure and their interactions. Monte Carlo simulations are used to
validate the randomness of the results obtained through CCD and Box-Behnken matrix design based
optimization methods. It is observed that changes in ramp rate produce significant effect in solder joint
fatigue life rather than changes in dwell time, but the dwell time at high temperature (high dwell) has a
negligible contribution to solder joint fatigue life. It is also found that the thickness of the mold has a
significant effect on the performance of the solder joint reliability (more than 50 %) as compared to that
from other factors. Besides the effect of individual factor, the interaction among factors also changes the
solder joint reliability. RSM based on Box-Behnken Matrix design offers the highest characteristic solder
joint fatigue life with a value of 2861 cycles or 41.1% enhancement from the initial design set. RSM based on
CCD offers the best goodness-of-fit measures over RSM based on Box-Behnken Matrix design. These results
show that RSM based on CCD has better accuracy in representing the sample points on response surface. |
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