隨著半導體製程技術的演進，銅已被廣泛作為內連線材料，由於具有較低的電阻率和較好的抗電致遷移能力。然而，銅與介電層存在著附著力的問題，且低溫下，銅便會與矽產生反應，此銅矽物在IC結構中，會造成元件失效。為了防止銅矽相互擴散，需開發高度熱穩定性、低電阻率和良好附著力的無阻障層。因此，本研究以射頻磁控濺鍍法（RF）沈積銅釕合金薄膜，及在不同氮流量分率的環境下沈積其氮化物薄膜。
我們研究了Cu(Ru)/Si和Cu(Ru, N)/Si之結構的熱穩定性，電阻量測顯示，經不同溫度退火(300°C ~650°C)，持溫一小時，Cu(Ru)/Si結構的熱穩定達500°C，而Cu(Ru, N)/Si結構的熱穩定性可達550°C。由XRD和SEM結果，Cu(Ru, N)/Si經退火達650°C，似乎能有效的防止銅矽物擴散到表面；一旦銅矽物擴散至表面，且造成銅膜不連續時，電阻率會遽增。由以上觀察可知，改善Cu(Ru)/Si的熱穩定性，N扮演一個重要的角色。

Copper (Cu) has been widely used as the interconnect material due to its lower electrical resistivity and better electromigration resistance. However, its poor adhesion, detrimental reactions between Cu and Si as well as the diffusion of Cu into Si or SiO2 substrates at relatively low temperatures have been serious problems. To prevent the rapid diffusion of Cu in interconnect technology, an effective barrierless layer with high thermal stability, low electrical resistivity and good adhesion is proposed. In this study, Cu(Ru) alloy and its nitride films were deposited by reactive radio-frequency (RF) magnetron sputtering in an Ar/N2 gas mixture.
We investigated the thermal stability of the Cu(Ru)/Si and Cu(Ru, N)/Si systems. After annealing in vacuum at 300°C to 650°C for 1 hr, the resistivity measurement results show that the Cu(Ru) film was stable up to 500°C and Cu(Ru, N) was stable up to 550°C. According to XRD and SEM results, the Cu(Ru, N) seem to block the Cu3Si to diffuse out to the surface, even after a 650°C annealing; if Cu3Si diffuse to the surface and result in discontinuous film, it gives rise to obviously increases in resistivity. The improvement in thermal stability achieved by adding a minor amount of nitrogen into Cu(Ru) alloy film was observed, suggesting that N played an important role in the stability improvement.

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