POWDER PRINTING EQUIPMENT FOR NEXT-GENERATION ELECTRONIC DEVICES : No subtitle = 차세대 전자 장치용 분말 인쇄 장비

다국어 초록 (Multilingual Abstract)

Additive manufacturing (AM) enables more efficient fabrication of electronic devices. Industries such as food, prototyping, and pharmaceuticals have already benefited from this bottom-up technology, and its functionality in electronics printing continues to expand. AM aims to reduce production costs, increase manufacturing efficiency, and ultimately deliver high-quality, affordable consumer products. Technologies capable of meeting these benchmarks can drive major transformations in manufacturing, which underscores the importance of ongoing research into more efficient production methodologies. For years, liquid-phase deposition has dominated large-scale additive manufacturing of printed electronics, with drop-on-demand (DOD) inkjets leading this field. However, the reliance of DOD inkjets on low-viscosity inks and short printing distances, combined with their susceptibility to nozzle clogging, highlights areas for improvement. This thesis explores alternative approaches to device manufacturing. It first addresses the issues of printing distance and nozzle clogging by demonstrating the use of high-viscosity commercial metal inks with continuous inkjet for circuit fabrication. It then introduces a new powder printing technique that eliminates the use of liquid solvents and enables the direct deposition of functional materials. The developed powder printer was evaluated using various materials and substrate combinations. The results show that the system consistently deposits functional metal, significantly simplifying pre- and post-printing processes of functional materials. Moreover, the findings demonstrate that powder printing represents a major advancement in the manufacturing for next-generation electronic devices.

목차 (Table of Contents)

• Abstract ii
• Acknowledgements iv
• Dedication vi
• Table of Contents vii
• List of Figures xi
• List of Tables xiii
• Abbreviations xiv
• Symbols and Units xvi
• Publications xviii
• Chapter 1 Introduction 1
• 1.1 Overview 1
• 1.2 Motivation for the thesis 1
• 1.3 Research objectives 2
• 1.4 Significance of the study 3
• 1.5 Organization of the thesis 3
• Chapter 2 Literature review 4
• 2.1 Introduction to additive manufacturing in electronics 4
• 2.2 Categories of rapid manufacturing processes 4
• 2.3 Printing technologies used in electronics fabrication 6
• 2.3.1 Contact printing 6
• 2.3.2 Non-contact printing 8
• 2.4 Inkjet printing technology 9
• 2.4.1 Drop-on-demand 10
• 2.4.2 Continuous inkjet 11
• 2.4.3 Inkjet printability parameters 12
• 2.5 Limitations of Liquid-based printing 15
• 2.6 Advances in solventless printing 16
• 2.6.1 Motivation for solvent-free printing 16
• 2.6.2 Solvent-free droplet printing 17
• 2.6.3 Solventless gaseous printing 17
• 2.6.4 Dry powder printing 21
• 2.7 Requirements for direct powder deposition 26
• 2.7.1 Health / safety considerations 26
• 2.7.2 Powder characterization 26
• 2.7.3 Flow measurement techniques 29
• 2.7.4 Deposition system 35
• 2.8 Research gap 36
• Chapter 3 Continuous inkjet printing of high-viscosity metal inks 37
• 3.1 Summary 37
• 3.2 Introduction 37
• 3.3 Experiments 39
• 3.3.1 Ink Preparation 39
• 3.3.2 High-viscosity ink printing 40
• 3.3.3 Real-time visualization 40
• 3.3.4 Development of unidirectional printing algorithm 40
• 3.3.5 Non-planar surface printing 41
• 3.3.6 Post printing characterization 41
• 3.4 Results 41
• 3.4.1 Stream formation 41
• 3.4.2 Modulated decomposition 42
• 3.4.3 Electrostatic deflection and selection 43
• 3.4.4 Deflecting high-viscosity metal inks 44
• 3.4.5 Drop selection and placement 46
• 3.4.6 Pattern scribing 47
• 3.4.7 Characterization of printed output 49
• 3.4.8 Applications 49
• 3.5 Conclusions 49
• Chapter 4 Development of functional powder printing 50
• 4.1 Overview 50
• 4.2 Introduction 50
• 4.3 Powder printing system design 52
• 4.3.1 Determination of the critical orifice diameter 52
• 4.3.2 Evaluation of flowability 52
• 4.3.3 Deposition head 53
• 4.3.4 Vibration-controlled flow 56
• 4.4 Experiments 60
• 4.4.1 Materials 60
• 4.4.2 Print process parameters 61
• 4.4.3 Characterization and Measurements 61
• 4.5 Results and discussions 61
• 4.5.1 Geometric architecture of functional powder deposition head 61
• 4.5.2 Generation of vibration 64
• 4.5.3 Transmission of vibration to hopper structure 64
• 4.5.4 Interaction with powder granules and flow regimes 65
• 4.5.5 Convective flow and ratchet effect 66
• 4.5.6 Flow cessation at the stop of vibration 68
• 4.5.7 Response time 69
• 4.5.8 Printed patterns characterization 69
• 4.5.8.1 Electrical characteristics upon annealing 73
• 4.6 Summary 73
• Chapter 5 Conclusions and future work 76
• 5.1 Epilogue 75
• 5.2 Summary of key findings 75
• 5.3 Economic implications of the powder printing technology 76
• 5.4 Recommendations for future research 78
• References 80
• Appendix 99
• 국문요약 101