藍寶石基板表面原子對蝕刻液分子的屏蔽效應影響圖案生成行為及其應用

The etchant screen effect of sapphire surface atoms on wet etching pattern formation behavior and application

林鴻宇(Hong-yu Lin)

指導教授 ： 劉正毓

國立中央大學/工學院/化學工程與材料工程學系/博士(2014年)

摘要

本論文研究主題為藍寶石基板在無黃光微影下經過濕蝕刻後圖案生成的行為和其應用。在第一部分，使用預溶鋁離子於蝕刻液中製程製作圖案化藍寶石基板。利用MOCVD成長GaN薄膜於藍寶石基板上，利用XRD和Raman量測，經過圖案化處理後的藍寶石基板可以降低GaN薄膜內的缺陷密度，裸晶輸出功率則會隨著覆蓋率增加而增加。在白光半球封裝後，不同圖案形貌基板的晶片有不一樣輸出功率的變化，經過分析後我們認為是因為封裝後晶片的光取出效率增益不同所造成，而增益程度隨著光形變寬而增加。
新型的無光罩圖案化藍寶石製程中，預溶鋁離子為其重要之參數。在第二部份，以不同預溶量觀察含水硫酸鋁和藍寶石基板的形貌。回饋到藍寶石基板上的含水硫酸鋁方塊隨著預溶粉末增加個數也隨之增加。然而過多的預溶量消耗過多的水分，因此回饋的含水硫酸鋁減少。藍寶石基板頂部的圖案受含水硫酸鋁成長型成四面金字塔型，底部則是形成具有弧面的三角錐。
從的文獻和研究成果中，濕蝕刻圖案化藍寶石基板的形貌普遍利用晶格面去推算，但無法解釋弧面三角錐的生成，我們從蝕刻圖案中利用利用表面原子與蝕刻分子的空間和電荷的屏蔽效應，解釋藍寶石基板經過濕蝕刻後圖案生成的行為。

關鍵字

圖案化藍寶石基板 ； 發光二極體 ； 濕式蝕刻 ； 螢光粉封裝

並列摘要

This thesis is about sapphire pattern formation behavior and application of natural patterned sapphire substrate (n-PSS). In the 1st part, we pre-dissolving Al3+ into etching solution to produce PSS, and this process is named as novel n-PSS fabrication process. After MOCVD epitaxy on these sapphire substrates, we use XRD and Raman to analysis GaN thin film quality. We find out that GaN on patterned sapphire substrate (PSS) has lower dislocation density. The bare chip output power increases with pattern coverage. After white light package, LED chips have different output power drop ratio on different sapphire substrate. After analysis, we think that the drop ratio depends on the LEE enhancement by package, and the enhancement increases with broadness of bare chip emission pattern.
In novel n-PSS fabrication process, the pre-dissolving Al3+ is an important factor. In the 2nd part, we pre-dissolve different Al2O3 and observe the natural hard mask, alunogen and pattern morphology. The number of alunogen cubic increases with pre-dissolving amount. However, the alunogen amount decreases with pre-dissolving amount, because H2O is consumed too much. The morphology of region effected by alunogen is pyramid, and the base of pattern is curved triangular pyramid.
From reference and previous experiment result, PSS morphology is usually studied by crystallography, but it can’t explain the curved triangular pyramid formation. We use atomic model and etchant screen effect to explain the sapphire pattern formation behavior well.

並列關鍵字

patterned sapphire substrate ； light emitting diode ； weting etching ； phosphor package

參考文獻

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