- 學位論文
滾輪式壓印技術製作大面積次微米圖案化藍寶石基板之研究
A Study of the Roller Imprinting Technology Applied to Fabricate Large Area Submicron Patterned Sapphire Substrates
摘要
摘要 為了改善發光二極體的光萃取效率，許多方法已被提出，這其中又以圖案化藍寶石基板(Patterned Sapphire Substrates, PSS)最受青睞，因為PSS不僅可以提升光萃取效率亦可增加內部的量子效率。而如何製作符合高效率LED的PSS，又能減少製程時間是一項具有挑戰性的工作。本研究採用自行設計開發的紫外光輔助的滾輪式奈米壓印設備搭配乾蝕刻製程，來進行次微米結構PSS的壓印研究。 首先利用步進投影方式定義大面積的次微米矽母模仁的圖案，再以乾蝕刻完成模仁結構製作；之後探討壓印材料對於模具的親疏水性實驗以及脫模分析，進行複製凹凸相反的聚二甲基矽氧烷(polydimethyl siloxane, PDMS)可撓性的子模仁。接著進行初步壓印實驗，推斷產生缺陷現象的可能原因。再針對主要製程參數中的壓印壓力與壓印速度進行分析，進而改善製程提高良率。最後對700/500 nm(直徑/間距)洞狀結構進行全晶圓轉印實驗，分別製作出2吋、4吋、6吋的全晶圓壓印結果，以及利用乾式蝕刻製作出次微米級的圖案化藍寶石基板。
並列摘要
Abstract Many methods had been proposed to improve the light extraction efficiency of the light emitting diodes (LEDs). Among these methods, patterned sapphire substrates (PSS) is the most promising technology since PSS not only can enhance the light extraction efficiency (LEE), but also improve the internal quantum efficiency (IQE). Moreover, how to fabricate PSS for high efficiency LED and also reduce the process time is a challenging task. This study used self-developed UV-assisted roller nanoimprinting equipment and dry etching to fabricate submicron PSS. The submicron pattern of silicon molds was defined by a projection stepper, and etching structure was produced directly by dry etching. A soft polymer such as polydimethylsiloxane (PDMS) was used as a mold to duplicate the pattern of the silicon mold. Enhancing the hydrophobic of silicon and reducing the thickness of PDMS were useful to prepare PDMS molds. Imprinting processes were carried out to analyze the causes of imprinting defect, and imprinting pressure and speed are the two major parameters to influence the imprinting qualities. In this study, hole structure with 700 nm diameter and 500 nm spacing on 2-inch, 4-inch and 6-inch were successfully imprinted on sapphire substrates. The following dry etching process accomplish the fabrication submicron PSS.