Estimation of Residual Stress and Strength in Fiber-Textured TiN Hard Thin Film
Yoshiaki AKINIWA, Takuya WATANABE and Hidehiko KIMURA
Abstract:TiN thin films were deposited on the polyimide films by reactive RF magnetron sputtering in Ar and N2 gas atmosphere. Most of the films possess strong <111> or <001> fiber texture. The properties such as the fiber texture, residual stress and tensile strength of the film were estimated by using X-ray method. The fiber texture of the film was strongly influenced by the N2 gas flow ratio and changed from <111> to <001> with increasing gas flow ratio. This change of the fiber texture affected on the grain size, residual stress and tensile strength. As <001> orientation become strong, the grain size and compressive residual stress increased. Stress distribution below the surface was also measured by using the constant penetration depth method and the grazing incidence X-ray diffraction (GIXD) method. Compressive residual stress was measured near the substrate and surface of the film. On the other hand, tensile residual stress was observed in the intermediate region. In-situ tensile tests were carried out for each specimen in order to estimate the strength of the films. The maximum X-ray stress measured during tensile loading process increased with decreasing grain size. When compared at the same grain size, <001> oriented films tend to show the larger strength than <111> oriented films. Key Words:TiN thin film, Sputtering, X-ray, Fiber texture, Residual stress, Stress distribution, Tensile strength