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Crystal Research and Technology |
Cryst. Res. Technol. 40,
135 (2005) - Abstract -
Void formation in the Cu layer during thermal treatment of SiNx/Cu/Ta73Si27/SiO2/Si systems
R. Hübner, R. Reiche, M. Hecker, N. Mattern, V. Hoffmann, K. Wetzig, H. Heuer*, Ch. Wenzel*, H.-J. Engelmann**, and E. Zschech**
Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
*Dresden University of Technology, Semiconductor and Microsystems Technology Laboratory, 01062 Dresden, Germany
**AMD Saxony LLC & Co. KG Dresden, Materials Analysis Department, 01330 Dresden, Germany
| Keywords | SiNx passivation, Cu metallization, diffusion barrier, void formation |
| PACS | 81.10.-h |
| DOI | 10.1002/crat.200410316 |
The thermal stability of a SiNx passivation layer and its influence on the annealing behavior of an amorphous Ta73Si27 diffusion barrier deposited between copper and SiO2 were analyzed by X-ray diffraction, glow discharge optical emission spectroscopy, Auger electron spectroscopy, scanning electron microscopy, and transmission electron microscopy. During heat treatment at a temperature Tan = 500 °C, diffusion of Cu atoms out of the Cu metallization into the SiNx passivation occurs. The Cu diffusion intensifies with increasing annealing temperature and annealing time and seems to be a necessary precondition for a defect formation process observed within the Cu metallization. Depending on the chemical composition of the SiNx/Cu interface, voids in the µm-range can be formed within the Cu film. Compared to an unpassivated sample, heat treatment leads to a reduced diffusion of Ta atoms from the barrier through the copper into the SiNx/Cu interface. The barrier crystallization process into Ta5Si3 occurring during annealing at Tan = 600 °C is principally not affected by the presence of a SiNx passivation.
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