AVS 53rd International Symposium
    Applied Surface Science Friday Sessions
       Session AS-FrM

Paper AS-FrM10
Copper Diffusion Barrier Performance of PEALD TaSiNC

Friday, November 17, 2006, 11:00 am, Room 2005

Session: Thin Film Characterization
Presenter: W. Zeng, University at Albany - The State University of New York
Authors: W. Zeng, University at Albany - The State University of New York
E.T. Eisenbraun, University at Albany - The State University of New York
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Continued downscaling of device dimensions has placed a high priority on the development of robust copper barrier/liner materials. Diffusion barrier requirements for shrinking device dimensions are very rigid, which include prevention of copper diffusion, good thermal/chemical stability, low resistivity, amorphous structure, etc. Moreover, the associated process used to deposit these materials needs to be carried out at reduced temperatures to allow integration with low-k materials which are mostly thermally fragile polymers, and are required to yield smooth, conformal films in aggressive trench/via structures, with atomic layer scale thickness and uniformity control. In this respect, atomic layer deposition (ALD) is emerging as a highly promising copper barrier/liner deposition technique, due to its inherent excellent step coverage and precise thickness control. In this work, a novel low temperature PEALD process for the growth of TaSiNC films has been developed employing a Genus Stratagem 200-mm wafer capable PEALD tool using TBTDET and trichloromethylsilane. The films were characterized using RBS, AES, XRD, SEM, AFM, ellipsometry, and four-point resistance probe. It was found that Si incorporation influenced both the resistivity and crystal structure of the PEALD TaSiNC films. As silicon content was increased from 0 to 11 at. %, resistivity increased from 270 µ@ohm@.cm to 3380 µ@ohm@.cm, while the texture changes from a nanocrystalline structure with an average grain size of 14 nm to an amorphous structure. The first pass copper diffusion barrier performance study of 5 nm-thick TaSiNC films, possessing a range of Si contents, determined that all films could prevent copper from diffusing into Si substrates after annealing Cu/TaSiNC/Si stacks at 500°C in 700 torr Ar ambient for 30 minutes irrespective of Si content. These results and proposed barrier failure mechanisms are discussed.