氮化鉬及氮化鉻在銅及鋁金屬化系統之擴散障礙特性

Abstract

本論文探討氮化鉬及氮化鉻作為銅和矽之間擴散障礙層的熱穩定性。氮化 鉬及氮化鉻係以濺鍍沉積法和快速熱氮化法沉積製備。我們使用接面二極 體的漏電流測量和X光繞射分析、二次離子質譜儀等分析方法來探討擴散 障礙特性及劣化機制。研究結果顯示最佳氮氣比例濺鍍沈積之500埃厚度 的氮化鉬對銅之擴散障礙熱穩定性可達600oC，而最佳氮氣比例濺鍍沈積 之500埃厚度的氮化鉻對銅之擴散障礙熱穩定性更可高達750oC。在氨氣中 以快速熱氮化法製成之氮化鉬及氮化鉻亦經証實為有效的擴散障礙層。以 最佳快速熱氮化溫度製成之氮化鉬及氮化鉻對銅之擴散障礙熱穩定性皆高 達750oC。此外，本論文也探討氮化鉬及氮化鉻和矽基板的接觸電阻特性 。 This thesis studies the effect of MoNx and CrNx diffusion barrier on the thermal stability of Cu/barrier/p+n junction diodes. The MoNx and CrNx films were prepared by two technoques: the reactive sputter deposited in N2 containing forming gas and rapid thermal nitridation (RTN) in NH3 ambient. To characterize the barrier capacity and failure mechanism of MoNx and CrNx in Cu metallization system, we used the electrical measurement of leakage current for junction diodes and the material analysis techniques of XRD, SMIS, AES, SEM, and XPS. For the barrier films sputter deposited with optimalcondition, a 50nm MoNx film made the Cu/MoNx/p+n junction diodes capable of sustaining a 30 min thermal annealing at temperature up to 600oC without degradation to the dioed's electrical characteristics. For a 50nm barrierlayer sputter deposited in the optimum condition, the corresponding thermally stable temperature was found to be 750oC. Both MoNx and CrNx layers formed by RTN treatment in NH3 ambient were found to possess effective barrier capability against Cu diffusion. It turns out RTN that both of the Mo-nitrideand Cr-nitride films formed in an apporpriate RTN treatment are thermally stable in Cu metallization system up to 750oC. Morever, contact resistance of the MoNx and CrNx contact system are also investigated.