Thermal Expansion Coefficients of Nano-Clustering Silica (NCS) Films Measured by X-Ray Reflectivity and Substrate Curvature Methods

摘要

Two methods are applied to measure the coefficient of thermal expansion (CTE) of nano-clustering silica (NCS) films. A direct measurement of the film thickness using X-ray reflectivity yields an intrinsic CTE of 12 +- 2 ppm/℃. From the analysis of the stress-temperature profile obtained by a substrate curvature method, the CTE of the NCS films is estimated to be approximately 9.7 ppm/℃, which almost agrees with the result of the X-ray reflectivity measurement. The advantage of each of these methods for CTE measurement of thin films is discussed.