複屈折測定とStoneyの式によるDLC膜の光弾性定数の評価

抄録

In order to use a diamond-like carbon (DLC) film as a protective film, adhesion to the substrate is important. The adhesion of DLC can be evaluated from the residual stress of the DLC film. The magnitude of the residual stress can be evaluated by Raman spectroscopy, but not the direction. For this reason, the laser photoelasticity method is used in this study. The purpose of this study is to find the photoelastic constant of DLC. DLC films were formed on glass substrates of three different thicknesses by plasma CVD and used as specimens. Then, the residual stress of DLC was obtained from the warpage of the specimens by Stoney's equation, and the birefringence caused by the residual stress was measured by laser photoelasticity. The photoelastic constant is obtained from the relationship between these two. As a result, it was found that the experimental results varied due to the non-uniformity of the film thickness. Observation of the film thickness by SEM showed that the photoelastic constant can be obtained by targeting a uniform range.