Shorter Field Life in Power Cycling for Organic Packages

2006 ◽  
Vol 129 (1) ◽  
pp. 28-34 ◽  
Author(s):  
S. B. Park ◽  
Izhar Z. Ahmed
Keyword(s):  
Fatigue Life ◽  
Temperature Distribution ◽  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Uniform Temperature ◽  
Transfer Coefficients ◽  
Solder Interconnects ◽  
Power Cycling ◽  
Plastic Ball ◽  
Accelerated Thermal Cycling

The importance of power cycling as a mean of reliability assessment was revisited for flip chip plastic ball grid array (FC-PBGA) packages. Conventionally, reliability was addressed empirically through accelerated thermal cycling (ATC) because of its simplicity and conservative nature of life prediction. It was well accepted and served its role effectively for ceramic packages. In reality, an assembly is subjected to a power cycling, i.e., nonuniform temperature distribution with a chip as the only heat source and other components as heat dissipaters. This non-uniform temperature distribution and different coefficient of thermal expansion (CTE) of each component make the package deform differently than the case of uniform temperature in ATC. Higher substrate CTE in a plastic package generates double curvature in the package deformation and transfers higher stresses to the solder interconnects at the end of die. This mechanism makes the solder interconnects near the end of die edge fail earlier than those of the highest distance to neutral point. This phenomenon makes the interconnect fail earlier in power cycling than ATC. Apparently, we do not see this effect (the die shadow effect) in ceramic packages. In this work, a proper power cycling analysis procedure was proposed and conducted to predict solder fatigue life. An effort was made for FC-PBGA to show the possibility of shorter fatigue life in power cycling than the one of ATC. The procedure involves computational fluid dynamics (CFD) and finite element analyses (FEA). CFD analysis was used to extract transient heat transfer coefficients while subsequent FEA–thermal and FEA–structural analyses were used to calculate temperature distribution and strain energy density, respectively.

Precision Evaluation for Thermal Fatigue Life of Power Module Using Coupled Electrical-Thermal-Structural Analysis

2011 ◽  
Author(s):  
Tomohiro Takahashi ◽  
Qiang Yu ◽  
Masahiro Kobayashi
Keyword(s):  
Fatigue Life ◽  
Temperature Distribution ◽  
Solder Joint ◽  
Thermal Fatigue ◽  
Thermal Structure ◽  
Inelastic Strain ◽  
Power Module ◽  
Thermal Fatigue Life ◽  
Power Cycling ◽  
Precision Evaluation

For power module, the reliability evaluation of thermal fatigue life by power cycling has been prioritized as an important concern. Since in power cycling produces there exists non-uniform temperature distribution in the power module, coupled thermal-structure analysis is required to evaluate thermal fatigue mechanism. The thermal expansion difference between a Si chip and a substrate causes thermal fatigue. In this study, thermal fatigue life of solder joints on power module was evaluated. The finite element method (FEM) was used to evaluate temperature distribution induced by joule heating. Higher temperature appears below the Al wire because the electric current flows through the bonding Al wire. Coupled thermal-structure analysis is also required to evaluate the inelastic strain distribution. The damage of each part of solder joint can be calculated from equivalent inelastic strain range and crack propagation was simulated by deleting damaged elements step by step. The initial cracks were caused below the bonding Al wire and propagated concentrically under power cycling. There is the difference from environmental thermal cycling where the crack initiated at the edge of solder layer. In addition, in order to accurately evaluate the thermal fatigue life, the factors affecting the thermal fatigue life of solder joint where verified using coupled electrical-thermal-structural analysis. Then, the relation between the thermal fatigue life of solder joint and each factor is clarified. The precision evaluation for the thermal fatigue life of power module is improved.

Effect of Lid Materials on the Solder Ball Reliability of Thermally Enhanced Flip-Chip Plastic Ball Grid Array Packages

2006 ◽  
Vol 306-308 ◽  
pp. 1043-1048
Author(s):  
Yi-Ming Jen ◽  
Hsi Hsin Chien ◽  
Tsung-Shu Lin ◽  
Shih Hsiang Huang
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Solder Ball ◽  
Flip Chip ◽  
Ball Grid Array ◽  
Stress Strain ◽  
Thermal Fatigue Life ◽  
Plastic Ball ◽  
Plastic Ball Grid Array ◽  
Solder Balls

This research studied the thermal fatigue life for eutectic solder balls of thermally enhanced flip-chip plastic ball grid array (FC-PBGA) packages with different lid materials under thermal cycling tests. Three FC-PBGA packages with different lid materials, i.e., Al, AlSiC, and Cu, were utilized to examine the lid material effect on solder ball reliability. The cyclic stress/strain behavior for the packages was estimated by using the nonlinear finite element method. The eutectic solder was assumed to be elastic-plastic-creep. The stable stress/strain results obtained from FEM analysis were utilized to predict the thermal fatigue life of solder balls by using the Coffin-Manson prediction model. Simulation results showed that the fatigue life of the FC-PBGA package with a Cu lid was much shorter than FC-PBGA packages with other lid materials. The relatively shorter fatigue life for the FC-PBGA package with a Cu lid was due to the complex constrained behavior caused by the thermal mismatch between the lid, substrate and the printed circuit board. The difference was insignificant in the fatigue lives between the package with an Al lid and the conventional package.

Analysis and Simulation of Thermal Transients and Resultant Stresses and Strains in TAB Packaging

1993 ◽  
Vol 115 (1) ◽  
pp. 34-38 ◽  
Author(s):  
M. A. Jog ◽  
I. M. Cohen ◽  
P. S. Ayyaswamy
Keyword(s):  
Thermal Stresses ◽  
Equivalent Stress ◽  
The Body ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Shear Stresses ◽  
Transfer Coefficients ◽  
Thermal Transients ◽  
Power Cycling ◽  
Accelerated Thermal Cycling

During normal power cycling of the electronic equipment, the differing coefficients of thermal expansion result in differential elongations. Because each level of packaging is subject to mounting constraints, the differential strains result in bending and shear stresses. Repeated duty cycling can cause fatigue at joints, at interfaces between different materials, at interconnection locations, or cause delamination of composite materials. Accelerated Thermal Cycling (ATC) is done to simulate the fatigue failures that may arise because of this power cycling. The current practice is to determine ATC stresses by assuming that the temperatures of various layers are equal and constant. In this study, we have relaxed the isothermal assumption and we provide results for thermal stresses and strains in a first level package. This is accomplished by accurately determining the transient temperature fields in various layers of the package. Temperature variations for different heat transfer coefficients have also been calculated. The results indicate that realistic estimates of thermal stresses and strains are only possible with models that allow for temperature variation in the body of the package. High equivalent stress values are obtained at the chip-heat sink interface and in the bumps connecting the leads to the chip.

The Reliability Assessment of Flip Chip Type Solder Joints Based on the Damage Integral Approach

1998 ◽  
Vol 516 ◽  
Author(s):  
Peng Su ◽  
Chen Zhou ◽  
Sven Rzepka ◽  
Matt Korhonen ◽  
Che-Yu Li
Keyword(s):  
Fatigue Damage ◽  
Flip Chip ◽  
Solder Joints ◽  
Integral Approach ◽  
Damage Rate ◽  
Power Cycling ◽  
Chip Carrier ◽  
Type Relation ◽  
Accelerated Thermal Cycling ◽  
Total Damage

AbstractThermal fatigue of flip-chip solder joints between a chip and chip carrier is a serious reliability concern. Differences in the temperature and/or in the coefficients of thermal expansion between the chip and substrate lead to stresses which may result in fatigue damage and eventual failure of the interconnect. Conventionally, the solder lives have been estimated by a Coffin-Manson type relation. However, this largely empirical approach becomes inadequate when comparing thermal histories that are widely different, as in the cases of accelerated thermal cycling and power cycling. In this study, we use a damage integral approach where the fatigue damage rate is calculated based on the momentary stress and strain (estimated analytically) experienced by the solder joints. The momentary damage is then integrated over the entire loading history to yield total damage at any moment.

Comparative Study of Phenolic-Based and Amine-Based Underfill Materials in Flip Chip Plastic Ball Grid Array Package

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Z. Kornain ◽  
A. Jalar ◽  
R. Rasid ◽  
S. Abdullah
Keyword(s):  
Adhesion Strength ◽  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Ball Grid Array ◽  
Bending Test ◽  
Temperature Cycle ◽  
Storage Test ◽  
Plastic Ball ◽  
Plastic Ball Grid Array ◽  
Epoxy Systems

Phenolic and amine epoxy systems are widely used as hardeners in underfill materials for flip chip packaging. A comparison was made between these two systems in order to evaluate the reliability performance of a flip chip plastic ball grid array (FC-PBGA). The coefficient of thermal expansion, glass transition temperature (Tg), Young’s modulus (E), and fracture toughness were revealed by using a thermal mechanical analyzer, a dynamic mechanical analyzer, and a single-edge notch three-point bending test, while moisture absorption study was performed using an 85°C/85% relative humidity chamber. The adhesion strength with different conditions of temperature and humidity was performed using a die shear test. The series of standard reliability tests such as accelerated temperature cycle test, pressure cooker test, thermal humidity storage test, and high temperature storage test were executed upon the FC-PBGA, which was filled by phenolic and amine epoxy systems of underfill materials. It was found that the adhesion strength of phenolic-based underfills is better than that of amine-based underfills in almost all test conditions. Phenolic-based underfills also demonstrated better reliability compared with amine-based underfills.

Interconnect Fatigue Failure Parameter Isolation for Power Device Reliability Prediction in Alternative Accelerated Mechanical Cycling Test

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Mahsa Montazeri ◽  
Cody J. Marbut ◽  
David Huitink
Keyword(s):  
Thermal Cycling ◽  
Flip Chip ◽  
Mechanical Stresses ◽  
Power Device ◽  
Reliability Test ◽  
Test Duration ◽  
Force Frequency ◽  
Solder Interconnects ◽  
Mechanical Cycling ◽  
Power Cycling

In this work, a rapid and low-cost accelerated reliability test methodology which was designed to simulate mechanical stresses induced in flip–chip bonded devices during the thermal cycling reliability test under isothermal conditions, is introduced and demonstrated using power device analogous test chips. By stressing these devices in a controlled environment, mechanical stresses become decoupled from the design and temperature, such that useful lifetimes can be predictable. Mechanical shear stress was cyclically applied directly to device relevant, flip–chip solder interconnects while monitoring for failure. Herein, finite element analysis (FEA) is used to extract various damage metrics of different solder materials, including PbSn37/63, SAC305, and nanosilver, in both thermal operation and the introduced alternative mechanical testing conditions. Plastic work density and strain are calculated in the critical solder interconnects as factors that indicate the amount of the damage accumulation per cycle during the mechanical cycling, thermal cycling, and power cycling tests. The number of cycles to failure for each test was calculated using the fatigue life model developed by Darveaux for eutectic PbSn solder, while for SAC305 Syed's method was used, and for nanosilver, the Knoerr et al. equations are applied. The effects of environmental temperature and shearing force frequency were studied for the mechanical cycling reliability test, where a modified Norris–Landzberg equation for mechanical cycling tests was explored using the simulation results. Finally, comparing the mechanical cycling with the equivalent thermal cycling and power cycling demonstrated a significant reduction in required test duration to achieve a reliability estimation.

Reliability Evaluation on Deterioration of Power Device Using Coupled Electrical-Thermal-Mechanical Analysis

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Takashi Anzawa ◽  
Qiang Yu ◽  
Masanori Yamagiwa ◽  
Tadahiro Shibutani ◽  
Masaki Shiratori
Keyword(s):  
Thermal Analysis ◽  
Fatigue Life ◽  
Temperature Distribution ◽  
Simulation Method ◽  
Thermomechanical Analysis ◽  
Mechanical Analysis ◽  
Power Module ◽  
Insulated Gate Bipolar Transistor ◽  
Power Cycling ◽  
Thermal Mechanical Analysis

This paper presents a simulation method to evaluate the thermal fatigue life of a power module. A coupled electrical-thermal analysis was performed to obtain the nonuniform temperature distribution of electric current. Then, a thermomechanical analysis was carried out based on the temperature distribution from the electrical-thermal analysis. Since crack propagation can change the route of heat transfer, a crack path simulation technique was used to investigate the fracture behavior of the power module. The crack initiates in the solder joint below the Al bonding wire of the insulated gate bipolar transistor module and propagates by increasing the diameter. The effect of the bonding type on power cycling fatigue life is also discussed. The fracture process was found to depend on the type of bonding. Lead frame bonding was found to be more effective than wire bonding.

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