In-situ system observation of thermal stress in thin films by in-lab X-ray equipment and synchrotron radiation

本研究利用日本同步辐射研究所常用的实验室X射线设备和超高功率的同步辐射X射线，研究了Cu、TiN和TiAlN薄膜中的残余应力。本研究的第一个目的是研究实验室X射线设备和超亮同步辐射系统测量薄膜应力的薄膜厚度极限。实验装置的最小厚度为100 nm的铜薄膜和800 nm的TiN薄膜，而10 nm的铜薄膜和100 nm以下的TiN薄膜的残余应力可以用超亮同步辐射测量。第二个目标是研究铜薄膜在热循环过程中的热应力行为。所用样品为厚膜和薄膜，有无氮化铝钝化膜。在3000 nm厚的薄膜中，未钝化的薄膜在加热和冷却阶段有明显的塑性变形行为，而钝化的薄膜在加热和冷却阶段有明显的滞后环。在100 nm和80 nm厚的AlN钝化薄膜的情况下，在加热和冷却循环中观察到没有滞后的线性行为。

Residual stresses in Cu, TiN and TiAlN films were investigated by the usual in-lab X-ray equipment and ultra high X-rays of synchrotron radiation, at Japan synchrotron Radiation Research Institute.The first object of this research was to investigate the limit of the film thickness available to measure stresses in thin films by the in-lab X-ray equipment and the ultra-bright synchrotron radiation system. 100 nm of Cu film and 800 nm of TiN films were the minimum thickness for the in-lab equipment, whereas residual stresses in 10 nm of Cu and below 100 nm of TiN films could be measured by ultra-bright synchrotron radiations.The second object was to investigate thermal stress behavior of thin Cu films during thermal cycles. Specimens used were thick and thin films with and without AlN passivation film. In the case of 3000 nm thick film, the behavior of plastic deformation was clear for the film without passivation whereas a clear hysteresis loop was observed in the film with passivation during heating and cooling stages. In the case of thin films of 100 and 80 nm thick films with AlN passivation, a linear behavior without hysteresis was observed during heating and cooling cycles.