化學氣相沉積法製備銅膜

Abstract

銅有低的電阻係數和優異的電子遷移抗拒性，是未來積體電路連線最被看 好的材料。我們自行組裝一套化學氣相沉積系統，使用Cu(hfac) TMVS當 做原料沉積銅膜，經由裝機過程中的摸索，逐步改善這套系統及其鍍膜特 性。本系統使用的多孔噴嘴能沉積較均勻的銅膜，銅膜沉積速率可達140 o/min ，當壓力低於500mtorr，沉積速率呈漸增的趨勢；壓力高於 500 mtorr，沉積速率則漸減。銅膜沉積在鎢表面的活化能為13.3 kcal/mole ，銅膜沉積在矽化鈷表面的活化能為11.5 kcal/mole。銅膜在高溫高壓的 條件下沉積，沉積速率較快，表面較為粗糙；所沉積銅膜的電阻係數較高 。在低溫低壓的條件下沉積，沉積速率較慢，表面較為平滑；所沉積銅膜 的電阻係數較低可達3μΩ-cm。在基板溫度低於170℃，沉積壓力小於10 mtorr，且試片未浸泡過氫氟酸的條件下，銅膜可選擇性的沉積於金屬而 不沉於二氧化矽表面。溫度低於 210℃時，銅膜可選擇性的沉積於金屬而 不沉於複晶矽表面。壓力低於500 mtorr 時，銅膜可選擇性的沉積於金屬 而不沉於矽表面。 Copper has an excellent electrical conductivity and high electromigration resistance, and is regarded as a potential material for application to future ULSI as the interconnection metal. The CVD system employed in this thesis study for the deposition of Cu film from the precursor Cu(hfac)TMVS is a new- system designed and built by ourselves. The performance of the Cu-CVD has been improved progressively from our experiences accumulated in our learning process. Uniform Cu film can be deposited by using the porous injector, and a maximun deposition rate of 140 o/min and a resistivity as low as 3 μ Ω-cm have been achieved. in addition, the selective Cu film deposition on metal versus SiO2 can be controlled by using a substrate temperature below 170 ℃ and a deposition pressure below 10 mtorr provided that the substrate is not treated with dilute HF solution prior to the Cu deposition