有機發光二極體蒸鍍遮罩製作與INVAR箔片特性之研究

本論文主要內容為執行與中部科學工業園區管理局之產學合作，高科技設備前瞻技術發展計畫－「OLED顯示器製程關鍵零組件製作技術開發計畫」的成果；計畫旨在發展有機發光二極體 (organic light-emitting diode, OLED)顯示器所使用之INVAR基材蒸鍍遮罩(shadow mask)，並進行黃光微影濕蝕刻製程參數與鋁金屬蒸鍍模擬之基礎研究，合作單位為景智電子/工研院/暨南大學。本研究內容以計畫兩大目標為主軸：一、以2-Step蝕刻製程開發開口最小線寬為30 μm之OLED蒸鍍遮罩技術；二、以研究INVAR特性發表四篇學術性論文。第一部分，我們依照實驗程序: 一、確認黃光製程解析度及均勻度實驗；二、確認背保護層抗蝕刻能力、強度、氣泡、填孔性及去膜性測試實驗；三、鋁蒸鍍模擬。最後我們成功地與合作單位協力開發出開口最小線寬為30 μm之OLED蒸鍍遮罩。第二部分，我們針對INVAR基材如期發表了四篇特性分析的論文：一、我們發現INVAR基材在照射高能珈瑪射線後，其表面會產生疏水現象，並且隨著輻射劑量的增加，INVAR基材的表面接觸角會跟著變大。經由高解析度掃描式電子顯微鏡分析，我們發現其結果是因為基材表面的氧化物產生龜裂， II 且劑量愈高愈明顯；我們同時也作了蝕刻、退火等處理後之接觸角分析。二、INVAR基材的彈回係數(springback factor)會因珈瑪射線照射及重複的冷熱交替處理而產生退化。若在照射輻射後做冷熱交替處理，發現彈回係數的退化會先消除而恢復至未經任何處理時之狀態，但隨著冷熱交替處理次數增加，退化反而又持續增加。我們相信這是因為因照射輻射而造成的彈回係數退化會在第一個的20次冷熱交替處理時有退火的效果，而隨著冷熱交替處理的次數增加最終主宰彈回係數退化的行為。三、我們以重覆(γ射線照射+冷熱交替)的處理方法來改善INVAR基材因γ射線照射或冷熱交替處理所產生的彈回係數退化，我們發現在經過5次的(γ射線照射+冷熱交替)循環後，彈回係數的退化便趨於穩定。四、我們使用原子力顯微鏡(Atomic force microscopy, AFM)來量測INVAR基材的熱膨脹係數(Coefficient of thermal expansion, CTE)，我們使用聚焦離子束(Focus-ion-beam, FIB)在INVAR基材表面蝕刻一條長5000 μm的溝痕，利用加溫時溝痕兩端的位移來計算INVAR基材的平均熱膨脹係數，經過系統熱漂移的校正後，我們得到了與供應商提供的INVAR熱膨脹係數非常相近的數值。

關鍵字

有機發光二極體；因瓦合金；遮罩

並列摘要

This thesis is the results report of the project : High-tech Equipments and Advanced Technology Development Project entitled “ Development of the Key Component in OLED Display Fabrication “. This project is financially supported by the Office of Central Taiwan Science Park. Cooperative organizations include the BriView Corporation, Industrial Technology Research Institute and National Chi Nan University. The aim of this project is to develop the INVAR shadow mask used in the evaporation process of OLED fabrication. The assignment of our jobs for this project including the basic researches of photolithographic wet etching process and simulated evaporation process using Al. There are two parts in this research corresponding to the two goals of the project: the first is to fabricate the OLED shadow mask with the smallest opening of 30μm by 2-Step etching technique, and the second is to publish 4 papers of the characterization of the INVAR foil. IV In the first part, we do the following experiments: 1. Confirm for the photographic etching resolution and uniformity. 2. Confirm for the back protective ability, strength, bubble generation, hole filling ability and peeling easiness. 3. Stimulated evaporation experiment using Al. In the second part, we have published 4 papers related to the INVAR foil studies: 1. We found a new phenomenon of the gamma-ray radiation-induced hydrophobic effects on the INVAR surface. It was found that when the INVAR alloy subjected to gamma-ray irradiation with different doses, the contact angle increased with irradiation dose. High resolution field emission scanning microscope (FE-SEM) analyses showed that irradiation might induce crack-like surfaces. It was believed that the damaged surface oxide attributed to the hydrophobic phenomenon. 2. We found both the gamma-ray irradiation and the repeated hot-then-cold stresses might induce the springback degradations of the INVAR. After applying the repeated hot-then-cold stresses to the post-irradiated INVAR foils, the springback factors were first restored to the value of fresh INVAR, and then reverted to an increasing trend. It was believed that the radiation-induced defects, which were closely related to the springback degradation, were possibly annealed during the first 20 hot-then-cold stress cycles. These cycles ultimately dominated the springback behavior of the stressed INVAR foils. 3. We proposed a method of repeated radiation+hot-then-cold treatments to improve both the gamma-ray radiation- and thermal stress-induced degradations of springback characteristics in INVAR alloy. It was found that both degradations in INVAR foil tended to be stabilized after 5 cycles of radiation+hot-then-cold treatments. V 4. We developed a method to measure the CTE of the INVAR foil using AFM. A FIB was used to etch a 5000 μm trench on the INVAR foil, and the average CTE of the INVAR foil could be calculated from the displacements of two side end points of the trench during temperature variation. After calibrating the thermal drift of the system from AFM images, the CTE obtained was quite close to the value of the bulk INVAR provided by the manufacturer.