Ultrathin Cr added Ru film as a seedless Cu diffusion barrier for advanced Cu interconnects

作者：Hsu Kuo Chung; Perng Dung Ching^*; Yeh Jia Bin; Wang Yi Chun

来源：Applied Surface Science, 2012, 258(18): 7225-7230.

DOI：10.1016/j.apsusc.2012.04.046

• RuCr alloy
• Diffusion barrier
• Cu interconnect
• Cu metallization

A 5 nm thick Cr added Ru film has been extensively investigated as a seedless Cu diffusion barrier. High-resolution transmission electron microscopy micrograph, X-ray diffraction (XRD) pattern and Fourier transform-electron diffraction pattern reveal that a Cr contained Ru (RuCr) film has a glassy microstructure and is an amorphous-like film. XRD patterns and sheet resistance data show that the RuCr film is stable up to 650 degrees C, which is approximately a 200 degrees C improvement in thermal stability as compared to that of the pure Ru film. X-ray photoelectron spectroscopy depth profiles show that the RuCr film can successfully block Cu diffusion, even after a 30-min 650 degrees C annealing. The leakage current of the Cu/5 nm RuCr/porous SiOCH/Si stacked structure is about two orders of magnitude lower than that of a pristine Ru sample for electric field below 1 MV/cm. The RuCr film can be a promising Cu diffusion barrier for advanced Cu metallization.

• 出版日期2012-7-1