Table Of ContentSolder Joint Reliability Prediction for
Multiple Environments
Andrew E. Perkins - Suresh K. Sitaraman
Solder Joint Reliability Prediction for
Multiple Environments
1 3
Andrew E. Perkins
Micron Technology, Inc.
8000 S. Federal Way
Boise, ID 83707
Suresh K. Sitaraman
Georgia Institute of Technology
School of Mechanical Engineering
Atlanta, GA 30332
ISBN 978-0-387-79393-1 e-ISBN 978-0-387-79394-8
Library of Congress Control Number: 2008934329
(cid:164) 2009 Springer Science+Business Media, LLC
All rights reserved. This work may not be translated or copied in whole or in part without the
written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring
Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or
scholarly analysis. Use in connection with any form of information storage and retrieval,
electronic adaptation, computer software, or by similar or dissimilar methodology now known
or hereafter developed is forbidden. The use in this publication of trade names, trademarks,
service marks and similar terms, even if they are not identified as such, is not to be taken as an
expression of opinion as to whether or not they are subject to proprietary rights.
Printed on acid-free paper.
9 8 7 6 5 4 3 2 1
springer.com
PREFACE
This book presents a methodology by which solder joint fatigue life prediction in
multiple environments can be done in a timely, accurate, and easy-to-use manner.
Analytical methods, numerical methods, and experimental data are used to inves-
tigate and develop solder joint reliability predictions for thermal cycling, power
cycling, and vibration environments. This book does not delve deeply into some
new aspect of solder joint reliability; rather it uses well known modeling methods
and tools in new ways to investigate issues relevant to solder joint reliability in
multiple environments.
The book is geared towards a broad audience, from graduate students to current
industry reliability experts. In fact, the two authors of the book reflect this range
well as Dr. Perkins has recently graduated with his PhD specializing in solder joint
reliability, while Dr. Sitaraman has an extensive research and publication history
in microelectronic packaging reliability.
Writing a book on a topic like solder joint reliability is a daunting task. This is
because the information may be common knowledge or technologically irrelevant
by the time all the research has been performed, studied, and the results published.
The pace at which the technology progresses can outpace the time it takes to
document the technology of interest. Even as this book is being written, continued
new advances in finite element modeling, material characterization, test methods,
packaging technology, etc. could threaten to make the book irrelevant. For in-
stance, this book focuses on Pb-containing solders, whereas the electronic packag-
ing industry has been moving towards Pb-free solder for a number of years. Addi-
tionally, this book focuses on ceramic area array packages, whereas the most
current technology is geared towards plastic ball grid array packages. A book on
plastic ball grid array Pb-free solder joint reliability may be immediately more
relevant and exciting to the industry. However, the technology is too immature to
begin answering some of the questions a more mature technology like Pb-
containing ceramic area array packages can address.
By harnessing the existing body of knowledge and personal experience with
Pb-containing ceramic area array packages, several important questions are inves-
tigated in this book:
• Can a single finite element model be made to study solder joint reliability under
thermal, power, and vibration environments? Is there any advantage to such a
model?
• How can solder joint fatigue life equations be developed and verified for ther-
mal cycling, power cycling, and vibration environments?
• Can solder joint reliability prediction be made simple enough for non-reliability
experts to quickly assess the effect of package design parameters on reliability?
• How well do Accelerated Thermal Cycle (ATC) test and Power Cycling (PC)
tests correlate? Can the two tests be related in any way so as to justify only do-
ing ATC tests?
• Does the sequencing of multiple environments play any role in solder joint reli-
vi Preface
ability? If so, what should be done to account for sequencing effect?
The task of predicting solder joint fatigue life for multiple environments raises
many more questions than answers, like any good problem will. The above ques-
tions are just a few that the authors felt capable of investigating and developing
methodologies for answering. It is our belief that the developed methodologies in
this book can be implemented for more current technologies such as Pb-free plas-
tic ball grid array packages. It is our hope that this book inspires others to tackle
more complex and exciting issues related to solder joint reliability prediction for
multiple environments.
TABLE OF CONTENTS
Chapter 1. Introduction...................................................................................1
1.1. Book Layout........................................................................................4
Chapter 2. Background....................................................................................7
2.1. CCGA and CBGA Electronic Packages..............................................7
2.2. CCGA Test Vehicle Description.........................................................9
2.3. Solder Material Behavior and Fatigue...............................................11
2.4. Damage Parameters for Fatigue Prediction.......................................18
2.5. Solder Joint Fatigue Failure Prediction.............................................19
2.6. Cumulative Damage Prediction: Miner’s Rule..................................21
2.7. Laser Moiré Interferometry...............................................................22
2.8. Vibration Theory...............................................................................26
2.9. Chapter Summary..............................................................................36
Chapter 3. Literature Review........................................................................39
3.1. Thermal Cycling................................................................................39
3.2. Power Cycling...................................................................................42
3.3. Vibration Environment......................................................................45
3.4. Multiple Combined or Sequential Environments..............................47
3.5. Pb-free Solder Joint Reliability.........................................................48
3.6. Chapter Summary..............................................................................58
Chapter 4. Unified Finite Element Modeling for Prediction of Solder Joint
Fatigue..........................................................................................65
4.1. Unified Finite Element Modeling Methodology...............................65
4.2. Choice of Material Models and Elements.........................................76
4.3. Compatibility of Element Types and Material Models.....................77
4.4. Calculation of Damage Parameter.....................................................78
4.5. Choice of Stress-free Temperature....................................................78
4.6. Chapter Summary..............................................................................80
Chapter 5. Validation of Unified FEM for Thermal Cycling and Power
Cycling Environments.................................................................83
5.1. Laser Moiré Interferometry...............................................................83
5.2. Laser Moiré Studies on CCGA Package Assembly...........................85
5.3. Laser Moiré Studies on CBGA Package Assembly...........................91
5.4. FEM Accelerated Thermal Cycling Verification with Laser Moiré
Interferometry....................................................................................96
5.5. Importance of Including Creep in Every Solder Joint of FEM..........99
5.6. Power Cycling Verification...............................................................99
5.7. Chapter Summary............................................................................101
viii Table of Contents
Chapter 6. Development of Fatigue Life Equations Under Low-Cycle
Thermal and Power Cycling.....................................................103
6.1. CBGA: 63Sn37Pb Solder Joint Fatigue Life...................................103
6.2. CCGA: 90Pb10Sn Solder Joint Fatigue Life...................................107
6.3. Chapter Summary............................................................................112
Chapter 7. Validation of Unified FEM and Development of Fatigue-life
Equations for Vibration............................................................113
7.1. Vibration Experimental Setup and Results......................................113
7.2. FEM Modal Analysis and Stress Distribution.................................117
7.3. Dye-and-Pry Analysis of Test Vehicle D: Solder Joint Failure
Location...........................................................................................119
7.4. Solder Joint Failure Mechanism and Microstructural Analysis.......121
7.5. Fatigue Life Prediction for 90Pb10Sn Solder Under Vibration
Loading............................................................................................124
7.6. Validation of Predictive Models......................................................129
7.7. Solder Joint Life Prediction for Sinusoidal Sweep Tests.................131
7.8. Chapter Summary............................................................................133
Chapter 8. Universal Predictive Fatigue Life Equation and the Effect of
Design Parameters.....................................................................135
8.1. Motivation for a Universal Predictive Fatigue Life Equation..........135
8.2. Method.............................................................................................136
8.3. Universal Fatigue Life Prediction Equation for CBGA Electronic
Packages under Thermal Cycling....................................................146
8.4. Discussion of the Predictor Variables..............................................146
8.5. Verification of Predictive Equation Using Literature Data.............150
8.6. Application: Military Obsolescence and Maintanence Scheduling.152
8.7. Chapter Summary............................................................................154
Chapter 9. Acceleration Factor to Relate Thermal Cycles to Power Cycles
for CBGA Packages...................................................................157
9.1. Power Cycling Thermal Environment.............................................157
9.2. Application of Developed AF Equation..........................................165
9.3. Chapter Summary............................................................................168
Chapter 10. Solder Joint Fatigue Failure under Sequential Thermal and
Vibration Environments........................................................171
10.1. Sequence Tests................................................................................172
10.2. Nonlinear Cumulative Damage Rule...............................................173
10.3. Extension of Nonlinear Sequential Cumulative Damage Rule to
Include Power Cycling (PC)............................................................176
10.4. Chapter Summary............................................................................177
Table of Contents ix
Chapter 11. Solder Joint Reliability Assessment for Desktop and Space
Applications............................................................................179
11.1. Approach and Setup for Application Examples..............................179
11.2. Example 1: Desktop........................................................................183
11.3. Example 2: Satellite.........................................................................186
11.4. Chapter Summary............................................................................189
LIST OF FIGURES
Fig. 1.1 General evolution of electronic packaging technology.............................1
Fig. 1.2 Unified modeling methodology for multiple environments......................5
Fig. 2.1 Cross-section of a CCGA electronic package and solder joint.................8
Fig. 2.2 Cross-section of a CBGA solder ball with 0.89mm diameter
90Pb10Sn ball............................................................................................8
Fig. 2.3 42.5 x 42.5 x 4.0mm CCGA test vehicle on 137 x 56 x 2.8mm
FR4 board................................................................................................10
Fig. 2.4 Electronically monitored daisy chain rings of CCGA test vehicle..........10
Fig. 2.5 Rheological model representing solder behavior....................................11
Fig. 2.6 Stress-Strain response for simple rheological model of solder to a
step stress load.........................................................................................11
Fig. 2.7 Plasticity models (a) Perfectly plastic (b) Elastic linear hardening
(c) Nonlinear hardening...........................................................................13
Fig. 2.8 Strain rate dependence on stress-strain curve for 60Sn40Pb solder........13
Fig. 2.9 Reverse yielding showing multilinear kinematic behavior (MKIN)
and multilinear isotropic hardening (MISO)...........................................14
Fig. 2.10 Primary, secondary, and tertiary stages of creep strain under a
constant load............................................................................................15
Fig. 2.11 Edge dislocation glide and climb mechanism.......................................15
Fig. 2.12 Typical Accelerated Thermal Cycle (ATC)..........................................17
Fig. 2.13 (a) Shakedown stabilization of stress-strain hysterisis,
(b) Ratcheting of stress-strain hysterisis loop, due to mean stress effects.
.................................................................................................................17
Fig. 2.14 Stress-Strain hysterisis loop for CBGA under 0/100oC 3cph
ATC. Stress-free temperature is 183 oC..................................................18
Fig. 2.15 Stabilized stress-strain hysterisis loop showing common
damage parameters..................................................................................19
Fig. 2.16 Schematic of four beam moiré interferometry to produce
deformation fringes N and N................................................................23
x y
Fig. 2.17 Schematic of deformation of a CBGA package assembly during
thermal cycling.......................................................................................25
Fig. 2.18 Schematic of deformation mechnanism of a CCGA column
during thermal cycling.............................................................................25
Fig. 2.19 SDOF system under harmonic excitation..............................................27
Fig. 2.20 Nondimensional amplitude (2.26) and phase angle (2.27) for a
harmonic SDOF.......................................................................................29
Fig. 2.21 Schematic for analytical vibration model of CCGA on a FR4 board....31
Fig. 2.22 Mode shapes from analytical method for FR4 with a 1089 I/O
CCGA......................................................................................................34
Fig. 2.23 Effect of interconnect stiffness on first mode shape.............................35
Fig. 3.1 Possible transition paths to lead-free solder............................................49
Fig. 3.2 Comparison of Young’s Modulus for SnPb and SAC solder..................51
List of Figures xi
Fig. 3.3 Comparison of creep strain rate for Sn37Pb and Sn3.9Ag0.6Cu ...........51
Fig. 3.4 Correlations of Joint Characteristic Life Scaled for Solder Joint
Crack Area versus Average Cyclic Shear Strain Range in
Temperature Cycling for Standard SnPb and for 100% Lead-Free
SAC Assemblies......................................................................................53
Fig. 3.5 Hysterisis loop for SAC CBGA solder joints under -40/125oC..............53
Fig 3.6 Hysterisis loop for SnPb CBGA solder joint under -40/125oC................54
Fig. 3.7 SAC CBGA after 800 thermal cycles.....................................................56
Fig. 3.8 Pb CCGA compared to the CuCGA.......................................................57
Fig. 3.9 (a) Deformation and failure of CuCGA at the (b) substrate side and
(c) board side...........................................................................................58
Fig. 4.1 CCGA 3D quarter FEM with a SOLID, detailed joint and
equivalent beams.....................................................................................67
Fig. 4.2 CBGA 3D quarter FEM with a solid detailed joint and
equivalent beams.....................................................................................67
Fig. 4.3 CCGA Solid Model and Equivalent Beam Model..................................68
Fig. 4.4 CBGA SOLID Model and Equivalent Beam Model...............................69
Fig. 4.5 CCGA Axial Force Equivalence. 3% average error..............................70
Fig. 4.6 CCGA Shear Force Equivalence. 7% average error...............................70
Fig. 4.7 CCGA Moment Equivalence. 7% average error.....................................71
Fig. 4.8 CCGA Creep Equivalence. 5% average error........................................71
Fig. 4.9 CBGA Axial Force Equivalence. 11% average error............................71
Fig. 4.10 CBGA Shear Force Equivalence. 12% average error...........................72
Fig. 4.11 CBGA Moment Equivalence. 15% average error.................................72
Fig. 4.12 CBGA Creep Equivalence. 12% average error....................................72
Fig. 4.13 3D quarter FEM of CCGA with boundary conditions..........................73
Fig. 4.14 Full FEM of CCGA under vibration loading with constrained
boundary conditions................................................................................74
Fig. 4.15 Hysterisis loops for CCGA with 20°C as stress-free temperature........79
Fig. 4.16 Hysterisis loops for CCGA with 183°C as stress-free temperature......79
Fig. 5.1 Schematic of the PEMI II moiré setup for observing
real-time deformations during thermal cycling.......................................84
Fig. 5.2 Cross-section of prepared sample before grating application.................84
Fig. 5.3 Temperature profile for laser moiré interferometry of CCGA...............86
Fig. 5.4 Whole-field displacement V field (left) and U field (right)....................87
Fig. 5.5 Vertical displacement of the ceramic substrate for CCGA.....................88
Fig. 5.6 Relative horizontal displacement between ceramic substrate and
board across the height of the solder joints for CCGA............................89
Fig. 5.7 U and V displacement fields of the outermost CCGA solder joint..........89
Fig. 5.8 CCGA with lid shown to minimize bending...........................................90
Fig. 5.9 CCGA with no lid shows package bending............................................90
Fig. 5.10 Temperature profile for laser moiré interferometry of CBGA..............91
Fig. 5.11 Whole-field displacement moiré fringes for CBGA at
temperatures along simulated ATC.........................................................92
Fig. 5.12 Ceramic substrate vertical displacement at outermost solder
