Research on Chemical Mechanical Polishing Mechanism of Novel Diffusion Barrier Ru for Cu Interconnect (eBook)

Supervisor’s Foreword 7
Preface 8
Acknowledgements 10
Contents 11
Abbreviations 15
1 Introduction 17
1.1 Development of Ultra-Large Scale Integrated Circuit 17
1.1.1 Sub-14 Nm Technology Node 17
1.1.2 The Application of New Materials for Interconnects 18
1.2 Ru as Novel Diffusion Barrier 21
1.2.1 Novel Barrier Materials 21
1.2.2 Properties of Ru 24
1.2.3 Preparation of Ru as Barrier Film 26
1.3 Chemical Mechanical Polishing (CMP) 28
1.3.1 Introduction of CMP Technology 28
1.3.2 CMP of BEOL 30
1.3.3 Challenges for CMP in Sub-14 Nm Technology Node 31
1.4 CMP of Ru 33
1.4.1 Requirements of Ru CMP 33
1.4.2 Advances of Ru CMP 33
1.4.3 Existing Problems in the CMP of Ru 37
1.5 Main Content of the Thesis 38
References 39
2 Material Removal Mechanism of Cu in KIO4-Based Slurry 44
2.1 Experimental 44
2.1.1 Static Etch Experiments 44
2.1.2 Characterization of Surface Film 44
2.1.3 Nano-Scratch Tests 45
2.1.4 CMP-Electrochemical Experiments 46
2.1.5 Chemical Mechanical Polishing Experiments 47
2.2 Analysis of Cu Surface Chemistry 48
2.2.1 Thermodynamic Parameters of Electrochemical Reactions 48
2.2.2 Characterization of Corrosion Products on Cu 49
2.3 Mechanical Properties of Cu Surface Film 51
2.3.1 Surface Morphology 51
2.3.2 Corrosion-Enhanced Mechanical Abrasion 54
2.4 Chemical Corrosion of Cu 56
2.4.1 Static Etching of Cu 56
2.4.2 Mechanical Abrasion-Enhanced Chemical Corrosion of Cu 58
2.5 Material Removal Mechanism of Cu 60
2.6 Conclusions 61
References 62
3 Material Removal Mechanism of Ru in KIO4-Based Slurry 64
3.1 Experimental 64
3.1.1 Sample Preparations 64
3.1.2 Electrochemical Measurement 65
3.1.3 Analysis of Surface Chemistry in Micro-Region 67
3.1.4 CMP-Electrochemical Experiments 68
3.2 Ru Surface Chemistry Analysis 68
3.2.1 Thermodynamic Parameters of Electrochemical Reactions 68
3.2.2 Characterization of Corrosion Products on Ru 69
3.3 Thickness of the Passive Film on Ru Surface 74
3.4 The Corrosion Properties of Ru 75
3.4.1 Passivation Properties of Ru 75
3.4.2 The Corrosion Kinetics of Ru 78
3.5 The CMP Mechanism of Ru 82
3.6 Conclusions 86
References 86
4 Tribocorrosion Investigations of Cu/Ru Interconnect Structure During CMP 89
4.1 Experimental 89
4.1.1 Tribocorrosion Experiments 89
4.1.2 The CMP-Electrochemical Experiments 91
4.2 Tribocorrosion Properties of Cu in KIO4-Based Solution 91
4.2.1 Comparison Between the Wear Track and Unworn Surface 91
4.2.2 The Electrochemical Signals 94
4.3 Abrasion-Accelerated Corrosion of Cu During CMP 97
4.4 Tribocorrosion Properties of Ru in KIO4-Based Solution 99
4.5 Abrasion-Accelerated Corrosion of Ru During CMP 101
4.6 Conclusions 102
References 102
5 Micro-galvanic Corrosion of Cu/Ru Couple in KIO4 Solution 104
5.1 Experimental 104
5.1.1 Sample Preparation 104
5.1.2 Confocal Raman Microscopy Analysis 105
5.1.3 KFM Mapping and In-situ AFM Measurements 105
5.1.4 Electrochemical Experiments 106
5.2 Corrosion Tendency of the Metal Components 106
5.3 Corrosion Products Analysis 108
5.4 Electrochemical Behavior of the Cu/Ru Couple 110
5.4.1 Corrosion Tendency in KIO4 Solution 110
5.4.2 EIS Results 111
5.5 Corrosion Kinetics of Cu/Ru Sample 114
5.5.1 Development of Galvanic Corrosion at Cu/Ru Interface 114
5.5.2 Galvanic Corrosion Mechanism at Cu/Ru Interface 116
5.6 Conclusions 117
References 118
6 Galvanic Corrosion Inhibitors for Cu/Ru Couple During Chemical Mechanical Polishing of Ru 119
6.1 Experimental 119
6.1.1 Electrochemical Experiments 119
6.1.2 Surface and Interface Characterization 120
6.2 Galvanic Corrosion Using Different Oxidants 121
6.3 Corrosion Inhibition Efficiencies of BTA and 1, 2, 4-Triazole 122
6.4 Solution/Metal Interface Characterization 124
6.5 The Corrosion Inhibition Mechanism 127
6.6 Conclusions 130
References 130
7 Synergetic Effect of Potassium Molybdate and Benzotriazole on the CMP of Ru and Cu in KIO4-Based Slurry 132
7.1 Experimental 132
7.2 Calculation of Galvanic Corrosion 133
7.3 Synergistic Effect of BTA and K2MoO4 on Corrosion Inhibition 136
7.4 Synergistic Effect of BTA and K2MoO4 on MRR Selectivity Between Cu and Ru 141
7.5 Conclusions 143
References 144
8 Conclusions and Recommendations 146
8.1 Conclusions 146
8.2 Recommendations 148