Characteristics of amorphous Ta-Si-C film as adiffusion barrier for copper metallization

• Main Authors: Wu-Jia Su, 蘇武加
• Other Authors: Jau-Shiung Fang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/xt44k5

碩士 === 國立虎尾科技大學 === 材料科學與綠色能源工程研究所 === 98 === Copper is to be used in deep submicron ultra-large scale integration (ULSI) metallization due to its lower resistivity and better electromigration resistance. Since Cu diffuses repidly in Si, and therefore introduces deep-level traps, a proper diffusion barrier is needed. The barrier should have low resistivity, high thermal stability, and good adhesion with Cu and the substrate. Ta-Si-N thin films failure temperature of 800 oC/1 hr, and the electrical resistivity was 800 μΩ-cm, but it has bad reproducibility.We expect C to replace N then add stability of process.This study prepared Ta-Si-C thin films using DC magnetron co-sputtering for copper metallization, subsequently followed by plasma surface treatment in Ar+H2 and Ar+N2 to evaluatie the phase transition and thermal stability of the annealed. Thin film properties and failure behavior of the studied films were elucidated by using four-point probe (FPP), X-ray diffraction (XRD), transmission electron microscopy (TEM). To reduce the thickness of Ta-Si-C(O)x , plasma treatmen on Ta-Si-C thin films by Ar+H2 and Ar+N2 , and prepare Cu/Ta-Si-C/Si structure, and plasma treatmen on Ta-Si-C thin films by, Ar+H2 and Ar+N2. Without plasma treatment on Ta-Si-C indicated that Ta-Si-C thin films is amorphours, and the electrical resistivity was 400 μΩ-cm, the electrical resistivity was 372 μΩ-cm using Ar+N2 plasma treatment, and the electrical resistivity was 361 μΩ-cm using Ar+H2 plasma treatment. The without plasma treatment or Ar+H2 plasma treatment induced the Ta-Si-C film became micro-crystallization TaSi2 phase when the film was annealed at 700 oC, and Ar+N2 plasma treatment resulted in Ta-Si-C film crystallite into TaSi2 phase when the film was annealed at 750 oC. Ar+H2 plasma treatment is effective in reducing resistivity of thin film, and Ar+N2 plasma treatment is promising in improving thermal stability of thin film. Using Ar+H2 plasma treatment on 5 nm Ta-Si-C film for Cu/Ta-Si-C/Si structure, the stacked film has a failure temperature of 750 oC/1 min, but using Ar+N2 plasma treatment on 5 nm Ta-Si-C film for Cu/Ta-Si-C/Si structure, the stacked film has a failed at 800oC/1 min. The experiment results indicated Ar+N2 plasma treatment is effectively on enhancing thermal stability of Ta-Si-C thin films.