拋光製程對於藍寶石基板表面平坦度之改善

Abstract

本文旨在探討拋光製程應用於改善藍寶石(Sapphire)基板之表面平坦度(Total Thickness Variation, TTV)。文中討論改變以下五項拋光製程參數：拋光製程壓力、拋光承載盤型式、拋光墊型式、基板承受壓力位置及拋光溶液濃度對於藍寶石基板表面平坦度之影響。 實驗結果顯示拋光壓力對於移除量影響較大，拋光壓力與藍寶石基板表面移除量成正比。雖然壓力降低藍寶石基板表面平坦度降低，但移除量不足將導致無法移除前製程刮傷及產能下降問題。改變拋光設備型式貼蠟拋光、修整拋光墊外緣，搭配貼蠟拋光型式減少藍寶石基板外緣移除量，雖然可改變基板表面形態進而改善藍寶石基板表面平坦度，但因貼蠟拋光型式在拋光過程中，隨溫度上昇，基板與承載盤間固定用黏著蠟熔解，會導致基板滑片問題，基板位置無法掌控便無法有效控制TTV。在藍寶石基板承載盤背面增加壓力片，使壓力集中在藍寶石基板放置處，結果會惡化藍寶石表面平坦度。調整拋光漿料二氧化矽(SiO2)溶液濃度，可改善藍寶石表面平坦度，拋光漿料二氧化矽溶液有一定飽和值，降低拋光漿料配比為20Wt(%)，可改善二氧化矽粒子沈澱結晶現象，使磨料粒徑均勻，研磨顆粒密度降低，流動性較佳使得表面移除量較均勻。 實驗目的在討論藍寶石基板之表面平坦度之控制，由實驗結果得知拋光壓力、基板承載型式、拋光漿料二氧化矽溶液濃度均會影響拋光結果，其中以拋光漿料二氧化矽溶液之濃度影響最鉅，濃度不足或超過，藍寶石基板之表面平坦度品質會變差。

The purpose of this study is to investigate the effect of polishing processes on the Total Thickness Variation of sapphire substrates. We conducted the five experimental parameters: Polishing Pressure, Carrier Type, Polishing Pad, Pressure Pad and the Concentration of Slurry, for research. The Polishing Pressure is the main factor and caused proportional to sapphire substrates removal rate. Lower Pressure could reduce the Total Thickness Variation of sapphire substrates, in the other hand the insufficient sapphire substrates removal rate could damage the scratching and the decline in production. Change the carrier of polishing process, trim the edge of the polishing pad, may change the morphology of the substrate and improve the Total Thickness Variation of sapphire substrates. During temperature rise in the polishing process, the substrates displacement by adhesive melting and cause incontrollable factor for TTV. Paste pressure plate on the carrier back side, will worsen the Total Thickness variation of sapphire substrates. Adjust the Silica (SiO2) solution concentration could improve the Total Thickness Variation of sapphire substrates. When reduce polishing slurry ratio to 20wt%, it could improve silica precipitated crystallization, decrease the abrasive particle density, make better fluidity and equality removal replacement on the Total Thickness Variation of sapphire substrates. The article with Concentration of polish slurry is the main factor to effect the Total thickness variation of sapphire substrates.