Diffusion barriers performance of amorphous Ta–Zr films in Cu metallization

✍ Scribed by Chuan Li; J.H. Hsieh; Z.Z. Tang

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 663 KB
• Volume: 202
• Category: Article
• ISSN: 0257-8972
• DOI: 10.1016/j.surfcoat.2008.06.152

✦ Synopsis

An amorphous Ta-Zr binary alloy diffusion barrier was studied in the Cu metallization. A Cu/Ta 50 Zr 50 /SiO 2 /Si stack with 50 nm thick amorphous film was prepared by co-sputtering can effectively suppress the penetration of Cu atoms into substrate upon annealing up to 650 °C. Examining the thermal stability of the barrier revealed that the crystallization of these amorphous Ta 50 Zr 50 films occurred at 800 °C, higher than its failure temperature. The results show that the existence of Cu layer first induced the formation of TaSi 2 and ZrSi 2 crystalline phases at 650 °C, followed by the formation of Cu 3 Si. A failure mechanism of the diffusion barrier is proposed based on the relation between thermal stress and the activation energy of barrier/ substrate interface reaction.