近年來由於環保意識抬頭，可達節能減碳目的之LED照明因此快速發展，做為LED照明鍍膜基板的單晶藍寶石晶圓也因此受到重視及探討。然而，單晶藍寶石晶圓為硬度相當高(莫氏硬度9)之硬脆材料，其平坦化之加工需要在長時間且高壓力的環境下進行，因此對作為材料移除平台的拋光墊是相當大的挑戰，除了抵抗拋光液之化學反應，同時得承受極大之機械力作用。有鑑於此，本研究建立一個拋光墊靜態特性雷達圖，利用雷達圖本身之綜合指標評估的優點，清楚呈現一款拋光墊之靜態特性，並利用此雷達圖觀察及比較不織布(Impregnated non-woven)及發泡固化(Foam solidification)兩種型式拋光墊於藍寶石晶圓拋光前後各靜態特性之變化趨勢及情形。不織布系列的拋光墊，如SUBA600或SUBA800在使用過後其特性雷達圖各指標之平均變化量為24~30%，而發泡固化型拋光墊，如IC1000則僅有11%左右之平均變化。由拋光墊承載比分析可知較大的拋光墊反應區(Spk)使不織布拋光墊有較佳之材料移除能力，而發泡固化拋光墊則由於較其較大的傳輸區(Sk)使其本身有極佳之剛性，其楊氏係數為37.91MPa約為不織布拋光墊之三倍。不織布拋光墊對於藍寶石晶圓有較佳的材料移除率，但在晶圓表面粗糙度之表現不如發泡固化型的拋光墊來的理想。由拋光墊之摩擦係數變化，發現拋光墊本身材料之性質對於摩擦係數有最大之影響，另外，硬度較大及壓縮性較大的拋光墊在摩擦係數實驗中將造成較大的摩擦係數。利用掃瞄式電子顯微鏡(Scanning Electron Microscope, SEM)觀察拋光墊，發現不織布拋光墊在拋光過後有纖毛糾結的現象產生，發泡固化拋光墊則僅有表面耗損的現象產生。不織布拋光墊由於其拋光墊結構，在拋光液流動性測試實驗中染色效果較發泡固化來的佳，可知其對於拋光液之涵養能力較佳因此相對有較佳之材料移除率。本研究在最後整合拋光墊靜態、動態特性及對藍寶石晶圓拋光之表現做結合，建立藍寶石晶圓拋光之拋光墊選用評估方法。本研究相關研究成果可做為LED產業用之藍寶石基板拋光墊開發參考，未來可延伸至其他硬脆基板，如單晶碳化矽基板拋光墊之應用。

The environmental protection issue has been arised recently and LED lighting for low carbon emissions and energy conserving has been rapidly developed. Mono-crystalline sapphire wafer as a deposited substrate for LED lighting has been studied popularly. However, the mono-crystalline sapphire wafer is a brittle material with high hardness that needs a long time and high pressure condition of polishing process. It is a challenge for polishing pad to bear both chemical and mechanical action at the same time. This study establishes a static property radar chart of pad. The static properties of pad can be presented clearly due to the advantage of integrated assessment by radar chart. The impregnated non-woven pad has changed for each index of radar chart before and after polishing about 24~30%, where as foam solidification pad is only 11%. From bearing ratio analysis, the larger Spk value of the impregnated non-woven pad induces better material removal ability. The large Sk value of foam solidification pad has Young’s modulus as 37.91 MPa, which is about three times larger than that of the impregnated non-woven pad. The impregnated non-woven pad has better material removal ability of sapphire polishing than that of the foam solidification pad, but the wafer surface roughness is in reverse. It can be found that material property of pad is signifiacnt to the coefficient of friction (COF) from the sapphire polishing test. Usually, the higher hardness and larger compression rate induce the larger COF during sapphire wafer polishing. Some pad asperities entangled together on the impregnated non-woven pad surface can be found from the scanning electron microscope observation. In the hydrodynamic test of slurry and pad, the impregnated non-woven pad has better pad coloring effect than that of the foam solidification pad because of the pad structure. Thus its slurry transferring ability should be better. Finally, this study has developed an evaluation method of pad analysis for sapphire polishing process based on the static properties of pads and performance of sapphire polishing. Results of this study can be applied on future pad design for sapphire wafer polishing in LED industry and also for polishing of other hard and brittle wafer, such as mono-crystalline SiC wafer.

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