High resolution residual stress gradient characterization in W/TiN-stack on Si(100): Correlating in-plane stress and grain size distributions in W sublayer

Year: 
2017
Month: 
6
Day: 
25
Pages: 
72-78
DOI: 
10.1016/j.matdes.2017.06.052
Author(s): 
Type: 
Journal Articles
Journal: 
Materials and Design
Volume: 
132
Abstract: 

Residual stress gradient characterization by the ion beam layer removal method (ILR), using a milling step of 10 nm, was applied toW/TiN stacks processed on thermal SiO2-insulated standard siliconwafers. The stress profiles indicate a pronounced stress gradientwith high tensile, as well as compressive stress concentrations in polycrystalline W and amorphous TiN sublayers ranging between 3.5 and −4 GPa. Electron backscatter diffraction shows that the Wsublayer exhibits zone T microstructure with nano-sized crystallites in the nucleation region at the interface to TiN and above that columnar or V-shaped grain morphology typical for competitive grain growth. In the W sublayer, the stress distributions correlate well with this in-plane crystallite size distribution on the base of a Hall-Petch mechanism, reaching a tensile maximum in the transition region between the nucleation layer and the region with columnar microstructure.