Temperature-Dependent Stress Measurements at Inlaid Copper Interconnect Lines
- AMD Saxony LLC and Co. KG, Wilschdorfer Landstr. 101, 01109 Dresden (Germany)
The 3-dimensional stress state of inlaid copper line structures in low-k dielectrics was measured using synchrotron micro X-ray diffraction ({mu}-XRD) at temperatures between 25 deg. C and 450 deg. C. The barrier layer (Ta or TaN/Ta) had only a low impact on the stress-temperature behaviour. However, an additional thick SiOxFy capping layer lowered the room temperature stress significantly compared to copper lines with a thin SiCxNy passivation. The effect of this thick capping layer on the slope of the stress-temperature curve was even more dramatic. Samples without a thick SiOxFy capping layer showed a transition from in-plane tensile stress to compressive stress between 150 deg. C and 250 deg. C, while samples capped with thick SiOxFy reached this point at higher temperatures or in some cases even stayed tensile up to 400 deg. C. This shift was also dependent on the copper line width. Furthermore, in 4{mu}m wide lines with thick SiOxFy cap the out-of-plane stress became more tensile with increasing temperature, leading to a reverse stress-temperature curve compared to the sample with thin SiCxNy passivation only. The extension of the tensile stress state up to temperatures of 400 deg. C together with the dependence of the stress on the structure geometry is supposed to cause stress migration problems in chip designs with combined low-k and SiOxFy ILD layers.
- OSTI ID:
- 20798188
- Journal Information:
- AIP Conference Proceedings, Vol. 817, Issue 1; Conference: 8. international workshop on stress-induced phenomena in metallization, Dresden (Germany), 12-14 Sep 2005; Other Information: DOI: 10.1063/1.2173560; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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