可藉由微影製程達到微小畫素的綠色螢光材料

Abstract

現今白光LED之螢光粉最為普遍的是以稀土材料作為原料來製作，但是開採稀土材料的過程，對於環境保育以及人類健康有相當大的傷害與負面影響。因此，我們希望能研發無稀土且高效率的螢光材料，以成為世人們科學研究與改進的目標。 本論文研究之第一部份，為使用有機染料Coumarin 6作為發光主體，其為無稀土材料且不含重金屬元素，很適合拿來製作我們的螢光粉，此外，我們在篩選有機染料會以高量子效率以及色彩飽和度高為標準來挑選，我們將Coumarin 6有機染料溶於其適合之溶劑後，使溶液在藍光LED激發下能激發出綠色之放光。接者再將我們的綠色溶液添加沉膜聚合物PVP，使其將有機染料分子包覆，並將配置好之螢光溶液放入真空腔體加熱乾燥並研磨成螢光粉。 第二部份，由於上述的螢光溶液在進行黃光微影製程時，我們的螢光膜會被顯影液所溶解掉，使得螢光陣列難以製作，因此，我們決定更換我們的成膜聚合物，改為使用PVB作為我們的成膜聚合物(此為本實驗室之黃容寬同學首先提出)，來測試其適不適合製作我們的螢光膜，首先，我們一樣先測試出適合與PVB搭配之溶劑並使其能達到較高的量子效率後，再測試實際將螢光溶液旋塗於玻璃基板上之情形，以測試是否適合用來製作我們的螢光陣列。 最後章節中，我們提出以高效率無稀土螢光溶液來製作綠色微米螢光陣列，可應用在微發二極體上。雖然微發二極體仍有轉移良率的困難有待突破，但我們所提出的做法可將螢光膜旋塗沉膜於基板上再經黃光微影及兩道反應離子蝕刻，即可得到綠色微米螢光陣列。我們的螢光膜優勢在於，不須考慮巨量轉移之轉移良率等問題，且光學顯微鏡觀察出於我們的陣列圖形區域有藍光光源激發可看出長方形綠光的激發光產生，因此對於作為微米發光二極體之轉換層是相當具有不錯的研發前景。 關鍵詞：無稀土、有機染料、白光LED、成膜聚合物、微發光二極體

Nowadays, rare earth materials are widely used as raw materials for white LED phosphors. However, the process of mining rare earth materials has a considerable harm and negative impact on environmental protection and human health. Therefore, we hope to develop rare earth free and efficient fluorescent materials, so as to become the goal of scientific research and improvement. In the first part of this thesis , we use the organic dye Coumarin 6 as the main body of luminescence, which is non rare-earth material and does not contain heavy metal elements, which is very suitable for making our phosphors. In addition, we will select organic dyes based on high quantum efficiency and high color saturation After the organic dye is dissolved in its suitable solvent, the solution can be excited to emit green light under the excitation of blue LED. Then, PVP is added to our green solution to coat the organic dye molecules, and the prepared fluorescent solution is heated and dried in a vacuum chamber and ground into fluorescent powder. In the second part, because the fluorescent film of the above-mentioned fluorescent solution will be dissolved by the resist developer, which makes it is difficult to make the fluorescence array. Therefore, we decided to replace our film-forming polymer and use PVB as our film-forming polymer to test whether it is suitable for making our fluorescent film(This was first proposed by Rong-kuan Huang from the laboratory). First of all, we will test it after the solvent matched with PVB can achieve high quantum efficiency. Then test the actual spin coating of fluorescent solution on the glass substrate to test whether it is suitable for making our fluorescence array. In the last chapter, we propose to use high efficiency rare-earth-free fluorescent solution to make green micro fluorescent array, which can be applied to micro LED. Although there is still some difficulties for the transfer yield of micro LED to be broken, our proposed method can spin coating the fluorescent film on the substrate, and then photo lithography and two reaction ion etching can obtain green micron fluorescence array. The advantage of our fluorescent film is that it does not need to consider the transfer yield and other issues of mass transfer and the blue light source can be used to generate the excitation light of rectangular green light in our array figure area. Therefore, it has a good research and development prospect for the conversion layer of micro LED. Key words: non-rare-earth-element, organic dye, white LED, film-forming polymer, micro LED