蘇國棟臺灣大學：光電工程學研究所曾慶章Tseng, Ching-ChangChing-ChangTseng2007-11-252018-07-052007-11-252018-07-052005http://ntur.lib.ntu.edu.tw//handle/246246/50895本篇論文探討矽材料熱蒸鍍遮罩在真空熱蒸鍍製程中使用的特性，並可在有機發光二極體顯示器製造過程中使用。 有機發光二極體顯示器具有低耗電、廣視角以及製造流程簡單的特性，而在世界各地引起廣泛的研究。因為其材料特性，使得我們無法使用傳統半導體顯影製程去進行圖形化製造，而必須在真空蒸鍍中使用熱蒸鍍遮罩去定義圖形。傳統的熱蒸鍍遮罩的材料為金屬，但其在連續使用後的清洗過程中易遭受酸性溶液的腐蝕。再者，一般金屬具有較大的熱膨脹係數以及較低的楊氏係數，這些性質在實際蒸鍍之中將會造成蒸鍍圖形的失真而不利於高解析度圖形的製造。除此之外，金屬遮罩的蒸鍍開孔邊壁通常為垂直形式，其在蒸鍍過程中易形成遮蔽效應使得材料累積在開口邊角之上而降低圖形解析度以及蒸鍍材料的利用率。 為了改善金屬遮罩的缺點，我們使用非等向濕蝕刻的方式用 (100) 矽晶片製作矽材料蒸鍍遮罩。因為其晶格特性，蝕刻出來的矽遮罩具有自然的54.7度斜角開孔。這個特性增加了蒸鍍材料入射的角度，降低了遮蔽效應以及提高了材料的利用率。 在模擬部分，我們探討90及54.7度斜角開孔的遮罩厚度以及與蒸鍍基板距離改變對沈積圖形的影響，並改變了54.7度的斜角開孔大小，觀察沈積圖形變化與實驗對照。模擬結果指出具54.7度斜角開孔的蒸鍍遮罩與基板的距離必須縮短以提高蒸鍍圖形的解析度。在比較之下，斜角開孔遮罩厚度改變對蒸鍍圖形的影響比起垂直開孔遮罩的影響來的更小。 在實際蒸鍍過程中，我們驗證了薄型矽材料遮罩在真空熱蒸鍍製程中的可行性。其蒸鍍結果並指出，透過精確的蒸鍍速率控制，我們能得到較佳的蒸鍍圖形。In this thesis, we demonstrate thin silicon shadow masks used for vacuum thermal evaporation (VTE) for manufacturing compact-size OLED (organic light emitting diodes) displays. Currently, the OLED displays attract many research attentions because novel organic materials for emitting the light at relative low cost. The fabrication processes of OLED make use of shadow masks for thermal deposition of organic materials due to etching difficulties. The metal shadow masks are widely used because of easy access. But in most cases, metal might be attacked by acids when it is cleaned to wash out residual organic or non-organic materials. Moreover, common metal masks have higher thermal expansion coefficient and lower young’s modulus these would cause pattern dispersion during the deposition of the high resolution sub-pixels. Besides, the openings of metal shadow masks are limited to vertical sidewall. It would cause shadow phenomenon and reduce deposition efficiency. In order to modify the defect of metal mask, we propose to use TMAH anisotropic wet etching process to fabricate thin silicon shadow masks. Due to the crystal orientation of (100) silicon wafers, the etched aperture slope of the silicon shadow mask has approximately 54.7 degree sidewalls. This feature increases the accepting angle of the openings around the edge; reduces shadow phenomenon and increases deposition efficiency. The simulation parts, we used 54.7 and 90 degree side wall mask to demonstrate the effects of changing mask thickness or separation of mask and substrate to the deposition patterns. We also compared with experimental results by changing the aperture size of 54.7 degree mask. The simulation results indicated that the separation of mask and substrate must be close to reduce resolution limit and the thickness of silicon shadow mask would not affect deposition profile. The experimental deposition results showed the feasibility of shin silicon shadow mask used in the vacuum thermal evaporation process. The results indicated that we could have smoother pattern under precise evaporation rate control.致謝 iv 中文摘要 vi Abstract viii Contents x List of Figures xii List of Tables xiv 1. Introduction 1.1 Organic electroluminescence 1 1.2 The classification of organic materials and processing technology 4 1.3 Silicon shadow mask 5 2. Simulation of Physical Vapor Deposition 2.1 Physical vapor deposition 8 2.1.1 Introduction 8 2.1.2 Vacuum thermal evaporation 9 2.1.3 The patterned film deposition through shadow mask 15 2.2 Simulation models 17 2.3 Simulation results 19 3. Fabrication of Silicon Shadow Masks 3.1 Silicon crystallography 27 3.1.1 Introduction 27 3.1.2 Miller indices 27 3.1.3 Crystal structure of silicon 28 3.1.4 [100]-Oriented silicon 29 3.2 Wet anisotropic etching 33 3.2.1 Introduction 33 3.2.2 TMAH etching of silicon 34 3.3 The process flow of silicon shadow mask 35 3.4 The final results of fabricated silicon shadow mask 39 4. Experimental Results and Discussion 41 5. Conclusion and Future Work 51 Reference 533397152 bytesapplication/pdfen-US真空熱蒸鍍濕蝕刻有機發光二極體蒸鍍遮罩micromachiningorganic light emitting diodes displayswet etchingshadow masksthermal depositionthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/50895/1/ntu-94-R92941066-1.pdf