探討不同結合度的砂輪磨削於藍寶石晶圓之聲射訊號特徵

本研究分析5種不同結合度之鑽石砂輪，在氧化鋁晶圓薄化製程中其聲射訊號上之差異。實驗平台為立式輪磨加工機，每顆砂輪各進行3次進給量為200 μm的磨削減薄製程，擷取磨削過程的聲射訊號後進行訊號分析。分析訊號後，從原始訊號中擷取出7種特徵，觀察5種砂輪的特徵差異，與研磨過程的訊號特徵變化。比較各類特徵，發現磨損率 > 0.1的砂輪與第一次進行磨削的藍寶石晶圓，因晶圓表面粗糙度值較後續進行的兩次低，所以訊號特徵表現較其他兩次不同。相反的，較小的磨損率 < 0.05則較不受加工件表面粗糙度所影響。不僅從特徵訊號中歸納出砂輪的表面變化差異，而且驗證不同結合度在聲射訊號頻帶上的比率。

This study analyzes the characteristics of the acoustic emission (AE) signals from five different grades of diamond grinding wheels used in the sapphire wafer grinding process. The experimental platform is a vertical wheel grinder. Each grinding wheel repeats sapphire wafer grinding process for 3 times, with 0.06 mm/min feeding rate, and the AE signals collected during the grinding process are analyzed. After the signal analysis, 7 signal features are extracted from the pristine AE signals to observe the signal difference of frequency bands and to correlate with surface condition among different wheels and sapphire wafers. In this research, we compare various signal characteristics. We found that the grinding wheel with RoW(Ratio of Wear) > 0.1 and the sapphire wafer in the first-time grinding process has different signal characteristics from the other two subsequent experiments due to its surface roughness is lower.  However, the grinding wheel with smaller RoW < 0.05 is less affected by surface roughness of the work piece. In this work, not only the difference arises from surface condition variation of the grinding wheel is generalized from the signal features, but also the ratio of frequency band in the AE signals comes from different wheel grade is verified.