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標題: 熱處理對有背覆複晶矽薄膜層的CZ矽晶片撓曲度的影響
The Effect of Thermal Heat Treatment on the Warp of the poly-back CZ Silicon Wafer
作者: 陳東旭
Chen, Tong-Hsu
關鍵字: Polysilicon film
出版社: 精密工程研究所
摘要: 本論文主要是研究LPCVD在0.25∼0.3torr,反應氣體矽甲烷(SiH4)所沈積1.5μm厚的複晶矽對晶圓撓曲度的影響。本研究以630℃、650℃、670℃等三種溫度來沈積複晶矽,分別觀察其對晶圓撓曲度的影響;另一方面,以900℃、1000℃、1100℃等不同溫度來對複晶矽做退火處理30分鐘,以期將複晶矽的殘留應力釋放進而降低晶圓的撓曲度值。同時探討重摻砷矽晶的相關材料性質如RRG、ORG、晶片內部缺陷…等,對晶圓撓曲度的影響。 此外,為了瞭解背覆複晶的矽晶圓在後續的磊晶製程以及IC製程中接受到高溫步驟時的影響,我們進行了短時間與長時間的熱處理模擬實驗。熱處理的溫度在950℃∼1200℃之間,模擬的時間在數分鐘至數十小時,觀察晶圓在不同溫度與不同時間的熱處理下,晶圓撓曲度的變化情形。 實驗結果顯示較高的溫度沈積複晶矽對矽晶圓撓曲度影響較小。而對複晶矽的退火處理以1100℃以上的溫度效果最好。在短時間與長時間的熱處理模擬實驗中,短時間內撓曲度有特異的回復現象,接著在更長時間的熱處理,撓曲度值則皆有下降趨於平穩的現象。實驗過程中,熱衝擊並非為影響撓曲度回升的原因,同時我們發現晶片在本實驗的熱處理情況下,氧凝聚物及相關缺陷在晶片中沿半徑方向分佈的觀察沒有明顯差異。 此研究對於厚複晶矽膜在IC工業上的應用,有相當重要的參考價值。
In this research, an 1.5μm polysilicon films were deposited by low pressure chemical vapor deposition (LPCVD) technique using Silane(SiH4) as reaction gas in a pressure range between 0.25 to 0.3 torr to study the effect of polysilicon film on wafer warp. The deposition temperatures were at 630℃、650℃ and 670℃. It is observed that polysilicon film deposited at 670℃ generated a minimal warp on the wafers that can be accepted by semiconductor industry. While the film deposited at 630℃ introduced a large compression stress on the wafers and induced severe wafer warp. Different thermal anneals were applied on the wafers prior or after the wafer polishing to reduce the polysilicon film stress, especially for the polysilicon film deposited at 630℃. The annealing temperature higher than 950℃ could effectively reduce the wafer warp within a four minutes annealing. However, when the annealing time is between four minutes to one hour, a compression stress is generated on the wafer to cause an even severe wafer warp. This unusual phenomenon is ascribed to the diffusion of oxygen in to polysilicon and also partially to the transformation of amorphous in to polysilicon during high temperature anneal. The study in this research provided a very important information to the IC industry for the application of the thick polysilicon film.
Appears in Collections:精密工程研究所



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