Diffusion barrier performance of reactively sputtered Ta-W-N between Cu and Si

  • Authors:
  • Yuzhang Liu;Shuangxi Song;Dali Mao;Huiqin Ling;Ming Li

  • Affiliations:
  • State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030, PR China;State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030, PR China;State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030, PR China;State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030, PR China;State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030, PR China

  • Venue:
  • Microelectronic Engineering
  • Year:
  • 2004

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Abstract

Thermally stable, amorphous Ta-W-N diffusion barrier layer between Cu and Si substrate was deposited by reactive sputtering. In the Cu/Ta-W-N/Si system, a 50 nm thick Ta-W-N film was adequate to suppress penetration of Cu into the Si substrate upon annealing at 700 °C without significant structure change and solid-phase reaction. The Ta-W-N barrier fails by migration of Cu through the Ta-W-N layer to the Ta-W-N/Si interface and reaction with Si to form copper silicide. The crystallization temperature of Ta-W-N in the Cu/Ta-W-N/Si sample is as high as 800 °C. The failure of Ta-W-N 800 °C is directly related to the crystallization of Ta W-N.