氮化鎢及氮化鉭對銅及鋁接觸金屬之擴散阻礙特性

Abstract

本研究探討濺度方法沉積的各種不同氮含量之氮化鎢及氮化鉭， 作為銅和矽之擴散障礙層於熱處理時之穩定性，並對氮化鎢及氮化鉭於氨 氣中進行快速退火處理，以作為銅之擴散障礙層的熱穩定性加以探討。 在電性方面，我們利用金屬/障礙層/p+n接面二極體在熱處理後的劣化程 度，來定義障礙層的熱穩定性。在材料分析方面，我們利用二次離子質譜 儀、掃描電子顯微鏡以及X光繞射分析，來探討其劣化原因。 在最佳條件 下的氮化鎢，於氮氣爐管退火30分鐘的熱穩定性可達550℃， 而經過快速 退火處理過的氮化鎢可使其對銅的熱穩定性提昇至575℃。 在氮化鉭方面 ，最佳條件之氮化鉭以及經過快速退火處理處理之氮化鉭的熱穩定度皆可 達到750℃以上。 此外，我們也探討此兩種氮化物作為鋁和矽之擴散障礙 層於熱處理時之穩定性。 This thesis studies the diffusion barrier properties of W-nitride aswell as Ta-nitride between Cu and Si substrate and Al and Si substrate. Thenitride films of various nitrogen contents were deposited using reactivesputtering in Ar/N2 mixing ambient. In addition, the effect of RTAtreatment in ammonia with respect to the diffusion barrier property is alsoinvestigated. In the electrical aspect, leakage current measurement on theCu/barrier/p+n junction diodes was used to characterize the capacity ofbarrier in the Cu metallization system. Degradation mechanism of the barrier films was also investigated using the techniques of SIMS, SEM, andXRD analysis. For the W-nitride deposited in optimal gas mixture of Ar/N2,the thermal stability of barrier layer was found to reach 550℃; additionalRTA treatment in ammonia raised the stability temperature to 575℃. For theTa-nitride deposited in optimal gas mixture of Ar/N2, either with or withoutRTA in ammonia, a barrier film of 50nm thickness is able to maintain the integrity of Cu/Ta-nitride/p+n junction diode up to at least 750℃.