Title Page
Abstract
Contents
Nomenclature 22
Chapter 1. Introduction 25
1.1. Research Background 26
1.2. Research Objectives 29
1.3. Thesis Outline 31
1.4. References 33
Chapter 2. Effect of a Controllable Electric Field via an Electrified Mask on Printed Structures 38
2.1. Introduction 39
2.2. Experimental Methods 44
2.2.1. Fabrication of the electrified mask 44
2.2.2. Generation of the charged aerosols 51
2.2.3. 3D aerosol nanoprinting system 55
2.2.4. 3D nanostructure characterization 62
2.2.5. Phenomenological modeling and calculation 63
2.3. Results and Discussion 64
2.3.1. Scaling analysis of particle dynamics 64
2.3.2. Printing 3D nanopillars via an electrified mask 69
2.3.3. Electrical conductivity effect of the mask 75
2.3.4. Voxel size control via the electric field strength 79
2.3.5. Voxel size control via the mask hole size 92
2.3.6. Multi-sized 3D nanopillars 96
2.3.7. Diverse shapes of 3D nanostructures by 3D nanostage movement 100
2.3.8. Diverse shapes of 3D nanostructures by the mask pattern design 113
2.3.9. Mechanical properties 118
2.3.10. Phenomenological model 119
2.3.11. Printing speed and the yield calculation 130
2.3.12. Comparison with the prior technology, 3D aerosol nanoprinting via IAAL 134
2.4. Conclusions 136
2.5. References 137
Chapter 3. Printing Efficiency Improvement and Cost Reduction via a Large-Area Electrified Mask 141
3.1. Introduction 142
3.2. Experimental Methods 149
3.2.1. Fabrication of a large-area electrified mask 149
3.2.2. Generation of the charged aerosols and 3D aerosol nanoprinting system 156
3.2.3. 3D nanostructure characterization 159
3.2.4. Mechanical and electrical simulation 160
3.3. Results and Discussion 161
3.3.1. 3D nanopillars printed in large area 161
3.3.2. Uniformity of the printed nanopillars 164
3.3.3. Limitation 167
3.4. Conclusions 169
3.5. References 170
Chapter 4. Conclusion and Future Works 173
Abstract (in Korean) 179
Table 2.1. Various designs of the electrified mask. 49
Table 2.2. Surface roughness data of the underside of the electrified mask obtained from the AFM. Rq and Ra of the mask were...[이미지참조] 50
Table 2.3. AFM data on the surface roughness of the substrate. Rq and Ra of the mask were measured in the point from Figure 2.10.... 61
Table 2.4. Electrical conductivities of the three coating materials were used in the simulation. The results of Figure 2. 18. (A) Ti,... 78
Table 2.5. Experimental conditions and structure geometries for the pillar-like structures and the line structures 90
Table 2.6. Statistical data for Figure 2. 20. and Figure 2. 25. Data represent mean ± s.d. (n=12). 91
Table 2.7. Experimental conditions and structure geometries for the helices. 112
Table 2.8. The comparison between the 3D aerosol nanoprinting via IAAL and this work. 135
Figure 1.1. Graphic outline of this dissertation. 32
Figure 2.1. Schematic illustrations of the IAAL process (right) and FE-SEM images of 3D nanostructures via the IAAL (left). This... 41
Figure 2.2. Schematic illustrations of 3D aerosol nanoprinting via the IAAL (right) and FE-SEM images of various 3D nanostructures... 42
Figure 2.3. FE-SEM images of 3D nanopillars fabricated by the 3D nanoprinting via the IAAL. (A) The voxel size of the nanopillars... 43
Figure 2.4. A schematic illustration of the fabrication steps of the electrified mask. ( ⅰ - ⅴ ) Frontside manufacturing processes for... 46
Figure 2.5. (A) FE-SEM images of the electrified mask with 4 μm hole patterns. (B) EDS mapping images that show Au was coated... 47
Figure 2.6. AFM surface roughness data on the bottom of the mask. (A) The measured points (50 μm x 50 μm) indicating Roman... 48
Figure 2.7. Schematic illustration of the charged aerosol generation method and size monitoring system. The charged aerosols were... 53
Figure 2.8. The size distribution graph and geometric diameter (dg) of the charged aerosols measured by the SMPS (left), and the TEM...[이미지참조] 54
Figure 2.9. Schematic illustration of the 3D nanoprinting system composed of a grounded electrostatic chamber, an electrified mask,... 57
Figure 2.10. AFM surface roughness data of the Si substrate. (A) The measured points (50 μm x 50 μm) indicating Roman numbers... 58
Figure 2.11. Schematic illustrations of the principle of the 3D aerosol nanoprinting via an electrified mask. 59
Figure 2.12. Schematic illustration of the cross-section of the electrified mask from Figure 2. 9. △V induced hole edge electric... 60
Figure 2.13. Schematic illustration of the scaling analysis of the nanoparticle dynamics in the printing system. Electrostatic force... 68
Figure 2.14. Electric field simulations before and after printing a tip. Before printing a tip, the electrical potential difference formed the... 71
Figure 2.15. FE-SEM image of 3D nanopillars growth as the printing time, T, progresses. After 1 min, stump-like tips appeared... 72
Figure 2.16. FE-SEM images of the printed 3D nanostructures at the edge of 3D nanostructure array. Roman numbers indicate the... 73
Figure 2.17. The measured voxel size and height of the 3D nanostructure in Figure 2.16. are summarized in graphs and table.... 74
Figure 2.18. Material dependence of the electrified mask. (A-C) Electric field simulation using three different metal materials of the... 77
Figure 2.19. The results of the electric field simulations by changing △V. In the simulation, only △V was changed and the other... 81
Figure 2.20. FE-SEM images of Au 3D nanopillars with diverse voxel sizes that varied with △V ; 75 V (upper), 100 V (middle), and... 82
Figure 2.21. Uniformity and reproducibility data of vertical 3D nanopillars in Figure 2.20. Experiments were repeated three times... 83
Figure 2.22. Uniformity and reproducibility data of vertical 3D nanopillars in Figure 2.20. Experiments were repeated three times... 84
Figure 2.23. Uniformity and reproducibility data of vertical 3D nanopillars in Figure 2.20. Experiments were repeated three times... 85
Figure 2.24. The results of the electric field simulations by changing d. In the simulation, only d was changed and the other... 86
Figure 2.25. FE-SEM images of Au 3D nanopillars with diverse voxel sizes that varied with d; 6 μm (left), 2 μm (right). The... 87
Figure 2.26. FE-SEM images of vertical Au 3D nanopillar arrays printed at 16.67 V/μm for 40 minutes (left). The electrical potential... 88
Figure 2.27. Uniformity and reproducibility data of vertical 3D nanopillars in Figure 2.25. Experiments were repeated three times... 89
Figure 2.28. The results of the electric field simulations by changing mask hole size. In the simulation, only mask hole size was... 93
Figure 2.29. FE-SEM images of Au 3D nanopillars with diverse voxel sizes that varied with mask hole diameter; 2 μm (left), 1 μm... 94
Figure 2.30. The graph of the voxel size variation tendency with the hole diameter at the constant electric field strength of 50 V/μm.... 95
Figure 2.31. FE-SEM images of the printed multi-sized 3D Au nanopillars. The △V variation from 200 V to 100 V (A) and from 75... 98
Figure 2.32. Position accuracy of the nanostructure array. (A) Low magnified tilted view FESEM image that corresponds to the... 99
Figure 2.33. Electric field simulation with substrate motion in three dimensions. The direction of the electric field lines on the tips was... 103
Figure 2.34. FE-SEM images of 3D overhanging structures (A-B), and 3D helices (C). 104
Figure 2.35. Tilt view FE-SEM images of the overhanging structures. ⅰ, ⅱ, and ⅲ indicate the measured voxel size data... 105
Figure 2.36. Uniformity and reproducibility data of 3D overhanging structures in Figure 2.35. Each statistical data represents measured... 106
Figure 2.37. Tilt view FE-SEM images of the overhanging structures. ⅰ, ⅱ, and ⅲ indicate the measured voxel size data... 107
Figure 2.38. Uniformity and reproducibility data of 3D overhanging structures in Figure 2.35. Each statistical data represents measured... 108
Figure 2.39. Tilt view FE-SEM images of the helical structures. ⅰ, ⅱ, and ⅲ indicate the measured voxel size data from the different... 109
Figure 2.40. Uniformity and reproducibility data of 3D helical structures in Figure 2.35. Each statistical data represents measured... 110
Figure 2.41. FE-SEM images of the 3D Cu-Pd rings fabricated by a writing mode. 111
Figure 2.42. FE-SEM images of the Au line structures. The structures in (left) and (right) were fabricated at E of 18.75 V/μm... 114
Figure 2.43. FE-SEM images of the thermally sintered line structures. The resulting structures represent reduced line width... 115
Figure 2.44. FE-SEM image shows the cross-section area of the as-printed line structure captured after FIB milling. 10 nm... 116
Figure 2.45. Measurement of electrical resistivity in the FE-SEM chamber using four-point nanoprobes. 117
Figure 2.46. Schematic illustrations for explaining theoretical calculations to derive the voxel size of the 3D nanostructure. (A)... 124
Figure 2.47. Top view FE-SEM images of the vertical pillar structures in Figure 2.20. and Figure 2.25. To analyze the... 125
Figure 2.48. Top view FE-SEM images of the vertical pillar structures in Figure 2.29. To analyze the correlation between Ds... 126
Figure 2.49. The graph of the voxel size of the printed nanostructures in Figure 2.20. and Figure 2.25. according to E. The... 127
Figure 2.50. The phenomenological modeling for the 3D overhanging structures and the 3D helices. 128
Figure 2.51. FE-SEM images of the printed 3D overhanging structures and 3D helices in Figure 2.34. (left) and structural... 129
Figure 2.52. Voxel size vs printing speed graph comparing all recently developed 3D nanoprinting techniques at micro and... 133
Figure 3.1. Minimum area required to potential applications such as solar cells (1cm x 2cm, left), thermoelectric modules (1cm x 1cm,... 144
Figure 3.2. Mechanical simulation results showing the bending stress of the small-area SiNx electrified mask in the experimental... 145
Figure 3.3. Mechanical simulation results showing the bending stress of the large-area SiNx electrified mask in the experimental... 146
Figure 3.4. Mechanical simulation results showing the bending stress of the large-area PUA electrified mask in the experimental... 147
Figure 3.5. The large-area PUA mask model to reduce bending stress by attaching backbone on the thin membrane. 148
Figure 3.6. The fabrication process of the large-area membrane with the hole-patterned array film that were supported by the... 151
Figure 3.7. The fabrication process of attaching the membrane to the paper. PUA 301 were spread on the boundary area between the... 152
Figure 3.8. The overall fabrication process of the large-area electrified mask using the membrane. 153
Figure 3.9. Schematic illustration and dimensions of the large-area electrified mask. The smaller hole diameter is 800 nm, the larger... 154
Figure 3.10. FE-SEM images of the fabricated large-area electrified mask. 155
Figure 3.11. Schematic illustration of the 3D nanoprinting system that composed of a grounded electrostatic chamber, a large-area... 158
Figure 3.12. Electric-field simulation results under the experimental conditions (△V of 100 V, d of 4 μm, and mask hole... 162
Figure 3.13. Optical microscopic image and top view FE-SEM images of the 3D nanopillars printed by the large-area electrified... 163
Figure 3.14. Optical microscopic images (upper) and tilted view FE-SEM images (lower) of the 3D nanopillars printed in the large... 165
Figure 3.15. Uniformity of the printed 3D nanopillars in the center and edge regions. A and B are corresponded to the center and edge... 166
Figure 3.16. A large-area printing model of stamp-like printing. 168
Figure 4.1. Summary charts for Chapter 2 and Chapter 3. 176
Figure 4.2. Schematic illustration of the future work, large area printing (over 1 cm x 1 cm) by introducing the piezo motor stage... 177