The Influence of the Cycle Frequency and Wave Shape on the Fatigue Life of Leaded Chip Carrier Printed Wiring Board Interconnections

1993 ◽  
Vol 115 (2) ◽  
pp. 173-179 ◽  
Author(s):  
H. D. Solomon
Keyword(s):  
Fatigue Life ◽  
Hold Time ◽  
Shape Effect ◽  
Printed Wiring Board ◽  
Wave Shape ◽  
Maximum Displacement ◽  
Cycle Frequency ◽  
Chip Carrier ◽  
Plastic Displacement ◽  
Wiring Board

This study employed different cycle frequencies, to determine the influence of cycle frequency on the fatigue life of leaded chip carrier printed wiring board (LCC/PWB) interconnections. Real LCC/PWB interconnections were mechanically cycled at 35°C or 125°C. The cycle frequency was varied by varying the ramp loading and unloading rates or by introducing hold times. Tests were run with equal hold times at the maximum and minimum displacements or only at the maximum displacement. The use of slower ramp cycling or the introduction in the hold times increased the plastic displacement and this decreased the fatigue life. This plastic displacement increase was corrected for, to unveil the underlying material response. The corrected data was similar to that observed in previous tests on simple, single, solder joints, where the plastic strain was kept constant while the cycle frequency was reduced. At 125°C there was a small influence of wave shape, with maximum displacement hold time tests showing the shortest fatigue lives and symmetric (maximum and minimum) hold time tests showing the longest fatigue lives. The fatigue lives of the tests run with ramp cycling were intermediate. This wave shape effect is relatively small, especially compared to the large overall influence of the cycle frequency.

Influence of Temperature on the Fatigue of CC/PWB Joints

1990 ◽  
Vol 33 (1) ◽  
pp. 17-25
Author(s):  
Harvey Solomon
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Hysteresis Loops ◽  
Cycle Fatigue ◽  
Printed Wiring Board ◽  
Influence Of Temperature ◽  
Joint Resistance ◽  
Influence Of Temperature On ◽  
Chip Carrier ◽  
Wiring Board

This is a study of the low cycle fatigue of chip carrier/ printed wiring board joints tested at -55° C (-67° F) and 125° C (257° F). It is contrasted to a previous study where the joints were tested at 35° C (95° F). The behavior at 35° C and 125° C was the same. Differences were noted, however, at -55° C. The hysteresis loops were distorted. The slopes of the displacement vs. fatigue life curves were slightly lower and the fatigue lives were longer. These differences were especially significant when the change in joint resistance was used to define failure.

Acceleration Factor to relate Thermal Cycles to Power Cycles for Ceramic Ball Grid Area Array Packages

2006 ◽  
Vol 3 (4) ◽  
pp. 177-193 ◽  
Author(s):  
Andy Perkins ◽  
Krishna Tunga ◽  
Suresh Sitaraman
Keyword(s):  
Fatigue Life ◽  
Environmental Parameters ◽  
Acceleration Factor ◽  
Junction Temperature ◽  
Design Parameters ◽  
Substrate Thickness ◽  
Electronic Packages ◽  
Printed Wiring Board ◽  
Ceramic Ball ◽  
Wiring Board

There is a need for a new Acceleration Factor (AF) that can relate Accelerated Thermal Cycle (ATC) fatigue life to Power Cycle (PC) fatigue life quickly and accurately in order to avoid over designing electronic packages for benign environments. An AF, such as the Norris-Landzberg AF, is only applicable when using it to predict fatigue life within the same environment, i.e. ATC to ATC or PC to PC. This work proposes an AF that takes into account the differences between ATC tests and PC tests for ceramic ball grid array (CBGA) packages by considering relevant design and environmental parameters. The new AF is based on relevant design parameters such as substrate size, substrate thermal conductivity, substrate thickness, coefficient of thermal (CTE) mismatch between the substrate and printed wiring board (PWB), PWB thickness, and environmental parameters such as temperature range (ΔT), frequency of cycles (f), and peak/junction temperature (Tj). Finite Element Models (FEM), experimental data, laser moiré interferometry, Design of Simulation (DOS), ANOVA, and regression analysis are used to develop the new AF. The new AF can be used to more accurately assess PC fatigue life from ATC tests so that expensive over-designing of electronic packages can be avoided for desktop/server/laptop applications.

Extending the Fatigue Life of Solder Grid Array (SGA) Electronic Packages

2003 ◽  
Vol 125 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Michael C. Larson ◽  
Melody A. Verges
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Opening ◽  
Shear Loading ◽  
Electronic Packages ◽  
Printed Wiring Board ◽  
Solder Interconnects ◽  
Force Mode ◽  
Wiring Board ◽  
Crack Growth Model

A fracture mechanics approach is used to investigate how the fatigue life of a solder grid array (SGA) may be increased or decreased by the application of an axial force to individual solder interconnects, such as may be induced by use of an underfill, by warping of a printed wiring board, or by some other mechanical constraint. The predominant loading on the SGA is assumed to be the shear resulting from a difference in thermal expansion between the package and the printed wiring board in the presence of cyclic temperature variations. A fatigue crack growth model, akin to the Paris law, is proposed for the cycles to failure of an individual cracked interconnect which undergoes a cyclic mode-II shear loading in conjunction with either a constant crack opening force (mode-I) or a constant crack closing force. For typical SGA packages in use today, the model predicts that forces on the order of only one newton can significantly impede or accelerate the propagation of a fatigue crack.

Energy Approach to the Fatigue of 60/40 Solder: Part I—Influence of Temperature and Cycle Frequency

1995 ◽  
Vol 117 (2) ◽  
pp. 130-135 ◽  
Author(s):  
H. D. Solomon ◽  
E. D. Tolksdorf
Keyword(s):  
Fatigue Life ◽  
Flow Stress ◽  
Plastic Strain ◽  
Strain Rate ◽  
Hold Time ◽  
Rate Dependence ◽  
Cycle Frequency ◽  
Influence Of Temperature ◽  
Life Data ◽  
Governing Factor

This study correlates previously published fatigue life data with the hysteresis energy, and compares this to the previous correlation’s with the applied plastic strain. It was found that, while the hysteresis energy could be used to describe the fatigue life, corrections must be made to account for the temperature and strain rate dependence of the flow stress. Because of these factors, it is believed that the plastic strain, and not the hysteresis energy, is the true governing factor in determining the fatigue life. Part I (described here) covers only the influence of temperature and cycle frequency for symmetric cycling. Part II, to be published, will deal with hold time and asymmetric cycling.

Fatigue Analysis of a Planarpak™ Surface Mount Component

1991 ◽  
Vol 113 (2) ◽  
pp. 194-199 ◽  
Author(s):  
I. Sharif ◽  
D. B. Barker ◽  
A. Dasgupta ◽  
M. G. Pecht
Keyword(s):  
Fatigue Life ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Printed Wiring Board ◽  
Surface Mount ◽  
Dimensional Finite Element ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Wiring Board ◽  
Three Dimensional Finite Element

This paper discusses the thermo-mechanical fatigue life analysis of an analog Avantek Planarpak™ surface mount device where the entire base of the component is soldered directly to the printed wiring board. The critical thermal stresses and strains are analyzed with the help of two and three-dimensional finite element models. The effect of solder voids and incomplete bonding is also investigated. The paper also shows how fatigue life estimations can be made using q generalized form of the Manson-Coffin equation even though the maximum solder attach stresses are found to be elastic.

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