IC PACKAGE RELIABILITY TESTING 1
1.1 Introduction 1
1.2 In-Process Quality Measurements 2
Wire Bond Quality 3
Die Attach Quality 4
Other Process Control Measurements 8
1.3 Package-Oriented Reliability Testing of Finished Devices:Moisture Testing 10
Failure Analysis of Moisture-Related Failures 11
Root Causes of Corrosion Failures 12
1.4 Package-Oriented Reliability Testing of Finished Devices:Thermal Cycle Testing 14
Bond Failures:Bond Pad Contamination 16
Intermetallic Formation and Other Elements of Bond Formation 18
1.5 Reliability Test Preconditioning:A New Direction 23
1.6 Summary 25
MOLD COMPOUND ADHESION AND STRENGTH 27
2.1 Introduction 27
2.2 Thermodynamic Consideration of Adhesion 28
Work of Adhesion 28
The Work of Adhesion from Contact Angle Measurements 30
Work of Adhesion in the Presence of Moisture and Lubricants 30
2.3 Adhesive Strength for Various Mold Compound Types 31
Adhesive Strength Measurements 31
Mold Compound Types 31
Adhesive Strength of Various Mold Compounds 32
2.4 Various Factors Which Influence Adhesion Strength 33
Effects of Lead Frame Oxides 34
Effects of Different Lead Frame Materials 38
Effects of Adhesion Promoters 40
Effects of Various Mold Release and Processing Aids 41
Effects of Mold Compound Rheology 42
2.5 Role of Adhesion in Surface Mount Operations 43
Moisture Absorption and Its Effect on Adhesion 45
Package Delamination and Cracking in VPR and SDIP 45
2.6 Role of Adhesion in Package Reliability 48
Metal Line Movement 48
Highly Accelerated Stress Test(HAST) 49
2.7 Physical Characterization of Mold Compounds 49
Physical Properties of Various Mold Compounds 49
Cure Kinetics 51
2.8 Outlook for Future Mold Compounds 53
2.9 Summary 54
MECHANICAL STRESS IN IC PACKAGES 57
3.1 Introduction 57
3.2 Stress and Strain Relations:An Overview 58
3.3 Stress Generation in IC Packages 61
3.4 Tools for Stress Determination in IC Packages 63
Finite Element Analysis 64
Strain Gauges for Stress Analysis 64
Moire Interferometry 64
Indirect Stress Determination 64
3.5 Application of Techniques to IC Packaging Problems 64
Eutectic Die Attach 65
Passivation Damage at Chip Corners 66
Ball Bond Stresses 68
Solder Reflow Damage 69
Tape Automated Bonding Inner Lead Stresses 72
Filler Particle-Induced Damage 73
Mechanical Warpage 73
Mechanical Damage 74
Parametric Shifts Related to Package Stresses 74
3.6 Solder Joint Stress and the Coffin-Manson Relation 75
3.7 Summary 76
MOISTURE SENSITIVITY AND DELAMINATION 79
4.1 Introduction 79
4.2 Moisture/Reflow Sensitivity Evaluations 81
Moisture Sensitivity Classification 81
Moisture Absorption:Preconditioning 83
Solder Reflow Damage 85
4.3 Impact on Temperature-Cycle Performance 91
4.4 Impact on THB Performance 92
4.5 Moisture Desorption:Bake-Out 93
4.6 Summary 94
THERMAL MANAGEMENT 97
5.1 Introduction 97
5.2 IC Package Thermal Characteristics 99
5.3 Factors Affecting Package Thermal Resistance 105
Package Design 105
Package Material Thermal Conductivity 107
Die Attach Material 111
Package Size and Die Size Effects 111
Package Defects 112
PCB Effect on Thermal Performance 113
The Effect of Neighboring Components 114
Heat Fins 115
5.4 Thermal Design Challenges of Multi-Chip Modules 115
5.5 Summary 116
ELECTRICAL PERFORMANCE OF IC PACKAGES 121
6.1 Introduction 121
6.2 Designing for Performance 123
6.3 Electrical Models for Packages and Interconnects 125
Low Frequency Models 125
6.4 Propagation Delay and Packaging 127
Clock Frequency,Bandwidth,and Rise Time 127
Propagation Delay 128
RC Delay 128
Time of Flight 128
6.5 Switching Noise 130
6.6 Signal Integrity 134
6.7 Crosstalk 135
6.8 Materials and Design Trends for High-Performance Packaging 138
6.9 Summary 143
SOLDERABILITY OF INTEGRATED CIRCUITS 145
7.1 Introduction 145
7.2 Electronic Soldering Basics 146
Soldering Definitions 146
Solder Joints for Electronic Packages 147
Solderability Defect Classifications 147
7.3 IC Package Designs,Materials,and Solderability Test Methods 148
Through-Hole Package Designs and Materials 148
Surface Mount Package Designs and Materials 150
Tape Automated Bonding Package Design and Materials 152
7.4 IC Solderability Defects 152
Through-Hole Solderability Problems 152
SMT Solder Electroplating Process Defects 155
SMT Lead Finish Defects 158
SMT Solderability Problems Due to Mechanical Damage 159
TAB Solderability Problems 161
7.5 Solderability of IC Packages to PCBs 162
Printed Circuit Boards 162
Electronic Solders,Fluxes,and Pastes 163
7.6 Summary 165
HERMETICITY AND JOINING IN CERAMIC IC PACKAGES 167
8.1 Introduction 167
8.2 Materials for Hermetic IC Packaging 169
8.3 Hermeticity Testing—History 173
8.4 Theory of Hermeticity Testing 174
8.5 Gross-Leak Testing Methodology 177
8.6 Hermeticity Failure Analysis 178
8.7 Alternatives to Hermetic Packaging 182
8.8 Summary 183
ADVANCED INTERCONNECT TECHNOLOGY 187
9.1 Introduction 187
9.2 MCM Technology Classifications 188
9.3 MCM Materials Selection 190
Substrate Materials and Design 191
Polyimide Dielectrics 194
Test Substrates 195
Power Density 196
9.4 Die Mounting and Stress 198
Die Bond Adhesive Strength 199
Flip-Chip Technology 200
9.5 Die Interconnection 201
Wire Bond Technology 201
Bond Optimization 203
9.6 MCM Packages 204
Substrate-Based Packages 204
9.7 Summary 205
APPENDIX:TECHNIQUE SUMMARIES 209
1 Acoustic Microscopy(C-AM) 209
2 Atomic Absorption Spectrometry(AAS) 213
3 Auger Electron Spectroscopy(AES) 214
4 Ceramic Plate Test(CPT)for Evaluating Solderability of IC Devices 215
5 Coulometric Method for Solderability Evaluation 218
6 Decapsulation Techniques 222
7 Differential Scanning Calorimetry(DSC) 225
8 Dynamic Mechanical Analysis 227
9 Dynamic Secondary Ion Mass Spectrometry(Dynamic SIMS) 229
10 Electron Probe X-Ray Microanalysis(EPMA) 230
11 Energy-Dispersive X-Ray Spectroscopy(EDS) 231
12 Finite Element Analysis(FEA) 232
13 Fourier Transform Infrared Spectroscopy(FTIR) 235
14 Inductively Coupled Plasma Mass Spectrometry(ICPMS) 236
15 Inductively Coupled Plasma-Optical Emission Spectroscopy(ICP-OES) 237
16 In Situ Strain Gauges 238
17 Ion Chromatography 240
18 Mechanical Testing in IC Packaging 243
19 Scanning Electron Microscopy(SEM) 247
20 Scanning Tunneling Microscopy(STM)and Scanning Force Microscopy(SFM) 248
21 Static Secondary Ion Mass Spectrometry(Static SIMS) 249
22 Thermogravimetric Analysis(TGA) 250
23 Thermomechanical Analysis(TMA) 252
24 Torsional Braid Analysis(TBA) 255
25 Wetting Balance Method to Evaluate the Solderability of IC Devices 258
26 X-Ray Laminography 260
27 X-Ray Photoelectron Spectroscopy(XPS) 263
28 X-Ray Radiographic Inspection 264
Index 267