銅/障礙層/二氧化矽/矽結構中氮化效應對鉬及鉻障礙特性之表現

Abstract

本論文探討濺鍍法沉積的各種不同氮含量之氮化鉬及氮化鉻，在銅/障 礙層/二氧化矽/矽結構中，作為擴散障礙層於熱處理時之穩定性。吾人使 用掃描式電子顯微鏡、歐傑電子能譜以及X光繞射分析，來瞭解氮化鉬及 氮化鉻本身之基本特性。在電性方面，吾人使用電容-電壓測量及加溫偏 壓法來偵測熱處理時穿過障礙層的銅離子。在材料分析方面，吾人使用二 次離子質譜儀、X光繞射分析以及掃描式電子顯微鏡，來探討障礙層特性 劣化原因。對氮化鉬而言，決定障礙層特性之主要因素為障礙層中沿著晶 粒邊界之擴散路徑。對於鉻及氮化鉻作為障礙層而言，在銅/障礙層/二氧 化矽/矽結構經過氮氣爐管700℃退火30分鐘後，其結構之完整性仍未遭破 壞。另外從二次離子質譜分析中，吾人得知較高氮含量之氮化鉻可以抑制 鉻在銅薄膜中之擴散。 This thesis investigates the nitridation effect on the barrier property of Mo and Cr layer in Cu/barrier/SiO2/Si MOS structure. The MoNx and CrNx fims weresputter deoisited in Ar/N2 mixed gas of various Ar and N2 flow rates. The ba-sic properties of the nitride films were investigated using the techniques of SEM, AES, and XRD analysis. In the electrical aspect, the C-V measurement andBTS were used to investigate the behavior of Cu in the Cu/barrier/SiO2/Si MOSstructure during thermal annealing. Degradation mechanism of the barrier filmswas also investigated using the techniques of SIMS, XRD, and SEM analysis. Forthe MoNx films, the dominant factor of deciding the barrier property should bethe diffusion paths along the grain boundaries in the barrier films. For the Cr and CrNx films, barrier property was not degraded even after the Cu/barrier/SiO2/Si structure thermally annealed at 700℃. Furthermore, the SIMS analysisrevealed that CrNx films with higher nitrogen contents can suppress the spread-ing of Cr into the Cu layer.