利用晶圓旋轉和/或位移改善燈源加熱晶圓之等溫性研究

Abstract

本篇論文是藉由量測八吋矽晶圓表面溫度，去探討在快速加熱製程(RTP)中利用燈源加熱晶圓的溫度均勻性研究。本論文的重點是在於，使用燈源加熱使晶圓升溫的過程中，藉由將晶圓加以旋轉或位移以及旋轉加位移，來改善加熱過程中晶圓表面之不均勻性。另外也探討燈源距離晶圓垂直距離對於晶圓溫度均勻性之影響;在本實驗中其參數範圍分別為，燈源到晶圓距離由30 mm 到 90 mm，晶圓旋轉速率為0 rpm 至 200 rpm 並且晶圓位移速率為 0 mm/s 到 20 mm/s。 由實驗數據結果可知，在有限範圍內增加晶圓旋轉和位移速率，可改善晶圓的不均溫性，但超過此範圍將獲得反效果。除此以外還發現增加燈源到晶圓的距離對溫度的均勻性也有所改善。最後，在本實驗系統中選擇一適當之晶圓旋轉速率和位移速率可得到一個較佳溫度均勻性；在一顆燈加熱，晶圓平均溫度為140℃時，可有一個最佳溫度不均勻性 0.5℃。

Temperature measurement on the surface of an eight-inch a silicon wafer is conducted in the present study to explore the temperature uniformity of a lamp heated wafer during a model rapid thermal processing. The possible improvement of the wafer temperature uniformity during the ramp-up period by the wafer rotation and/or translation are explored. The effects of the lamp-to-wafer separation distance on the wafer temperature uniformity are also examined. In the experiment the lamp-to-wafer separation distance is varied from 30 mm to 90 mm, the rotation rate of the wafer is varied from 0 to 200 rpm , the wafer translation speed is varied from 0 to 20 mm/s. The measured data clearly show that increasing the wafer rotation rate and translation speed to certain levels can significantly improve the temperature uniformity of the wafer. Beyond these levels opposite effects are noted. Besides, we also observe that for a longer lamp-to-wafer distance the wafer temperature is more uniform. Finally, the temperature nonuniformity on the wafer can be ratter small for a suitable choice of the wafer rotation rate and translation speed.