Investigations on Microstructure and Mechanical Properties of the Cu/Pb-free Solder Joint Interfaces (eBook)

Parts of this thesis have been published in the following journal articles: 6
Supervisor's Foreword 7
Acknowledgments 8
Contents 9
Nomenclature 12
1 Research Progress in Pb-Free Soldering 13
1.1 Soldering in Microelectronic Package 13
1.1.1 Microelectronic Package 13
1.1.2 Soldering Technology 14
1.2 Pb-Free Solders in Microelectronics 15
1.2.1 Sn--Pb Solder 15
1.2.2 Requirements for Pb-Free Solders 15
1.2.3 Common Pb-Free Solders 16
1.3 Interfacial Reaction in the Solder Joints 23
1.4 Reliability of Solder Joints in Electronic Circuit 26
1.4.1 Loadings Suffered by Solder Joints 26
1.4.2 Mechanical Properties of Pb-Free Solders 27
1.4.3 Fracture Behavior and Strength of Solder Joints 33
1.4.4 Fatigue Damage Behavior of Solder Joint 36
1.4.5 Creep Behavior of Solder Joints 37
1.4.6 Problems in Research 38
1.5 Research Content and Purpose of This Dissertation 39
References 41
2 Fracture Behavior of IMCs at Cu/Pb-Free Solder Interface 46
2.1 Introduction 46
2.2 Experimental Procedure 47
2.2.1 Indentation Test of Interfacial IMC Grains 47
2.2.2 Fracture of IMCs Induced by Deformation of Solder 48
2.2.3 Fracture of IMCs Induced by Deformation of Substrate 49
2.3 Shear Fracture Behavior and Strength of Cu6Sn5 Grains 51
2.4 Fracture Behavior of Cu6Sn5 Induced by Deformation of Solder 55
2.4.1 Growth Behavior of Cu6Sn5 at Sn--4Ag/Cu Interface 55
2.4.2 Fracture Behavior at Sn--4Ag/Cu Interface 58
2.4.3 Applied Stress and Fracture Behavior of Cu6Sn5 Grains 62
2.5 Fracture Behavior of Cu--Sn IMCs Induced by Deformation of Substrate 63
2.5.1 Morphology of IMCs at Sn--4Ag/Cu Interface 63
2.5.2 Fracture Behavior of Interfacial IMC Layer 64
2.5.3 Fracture Mechanisms Induced by Deformation of Substrate 70
2.6 Brief Summary 75
References 76
3 Tensile-Compress Fatigue Behavior of Solder Joints 78
3.1 Introduction 78
3.2 Experimental Procedure 79
3.3 Experiment Results 80
3.3.1 Tensile and Fatigue Behavior of Sn--4Ag/Cu Interface 80
3.3.2 Tensile and Fatigue Behavior of Sn--58Bi/Cu Interface 87
3.3.3 Fatigue Behavior of Sn--37Pb/Cu Interface 92
3.3.4 Evolution in Strength of Solder During Aging 95
3.4 Tensile-Compress Fatigue Damage Mechanisms 96
3.5 Brief Summary 97
References 98
4 Shear Creep-Fatigue Behavior of Cu/Pb-Free Solder Joints 101
4.1 Introduction 101
4.2 Experimental Procedure 103
4.3 Shear and Creep-Fatigue Behavior of Sn--4Ag/Cu Solder Joint 104
4.3.1 Shear and Stress Relaxation Behavior 104
4.3.2 Strain--Time Relationship During Creep-Fatigue Process 106
4.3.3 Deformation and Fracture Behavior of Solder Joint 108
4.3.4 Evolution in Microstructure of Solder 112
4.3.5 Creep-Fatigue Mechanisms of Sn--4Ag/Cu Solder Joint 113
4.4 Shear and Creep-Fatigue Behavior of Sn--58Bi/Cu Solder Joint 117
4.4.1 Shear Behavior of Sn--58Bi/Cu Solder Joint 117
4.4.2 Creep-Fatigue Fracture Behavior of Sn--Bi/Cu Solder Joints 120
4.4.3 Deformation Behavior of Sn--Bi Solder 123
4.5 Brief Summary 126
References 127
5 Thermal Fatigue Behavior of Sn--Ag/Cu Solder Joints 129
5.1 Introduction 129
5.2 Experimental Procedure 130
5.3 Thermal Fatigue Behavior 132
5.3.1 Thermal Fatigue Behavior at Low Strain Amplitude 132
5.3.2 Thermal Fatigue Behavior at Medium Strain Amplitude 137
5.3.3 Thermal Fatigue Behavior at High Strain Amplitude 140
5.3.4 Thermal Fatigue Fracture Surface 141
5.4 Thermal Fatigue Damage Mechanisms 143
5.4.1 Thermal Fatigue Damage Process 143
5.4.2 Deformation Mechanisms of Solder 144
5.4.3 Influencing Factors on Thermal Fatigue Life 147
5.5 Brief Summary 147
References 148
6 Conclusions 151