Abstract: A method for measuring interfacial stress and residual stress in multilayer thin films coated on a substrate is disclosed. First of all, a residual stress measurement process is applied to each thin film of a multi-layered structure. Subsequently, after two kinds of interfacial stress (FHL, FLH) are calculated, a mathematical formula for estimating at least one adjusting parameter is derived based on the two interfacial stresses. As a result, a modified Ennos formula is obtained by involving the adjusting parameters into the Ennos formula, such that a residual stress in the multi-layered structure (i.e., multilayer thin films) is therefore calculated by using the modified Ennos formula.

Abstract: Conventional optical-transmission-type residual stress measuring apparatus cannot be used for completing the measurement of residual stress in an optical film having light reflective property, and conventional optical-reflection-type residual stress measuring apparatus is known failing to achieving the measurement of residual stress in an optical thin film having transparent or translucent property. In view of that, the present invention discloses a system for measuring residual stress in optical thin films, which is able to be utilized for achieving the residual stress measurement of respective optical thin film having transparent or translucent property and that of respective optical thin film having light reflective property.

Abstract: Conventional optical-transmission-type residual stress measuring apparatus cannot be used for completing the measurement of residual stress in an optical film having light reflective property, and conventional optical-reflection-type residual stress measuring apparatus is known failing to achieving the measurement of residual stress in an optical thin film having transparent or translucent property. In view of that, the present invention discloses a system for measuring residual stress in optical thin films, which is able to be utilized for achieving the residual stress measurement of respective optical thin film having transparent or translucent property and that of respective optical thin film having light reflective property.

Abstract: The present invention disclose a method for measuring a thermal expansion coefficient of a thin film, in which the thin film is first deposited on two substrates having different thermal expansion coefficients under the same conditions. For each of the two deposited substrates, a relationship between the thin film stresses and the measuring temperatures is established by using a phase shifting interferometry technique, in which the stresses in the thin films are derived by comparing the deflections of the substrates prior to and after the deposition. Based on the two relationships the thermal expansion coefficient, and elastic modulus, E f ( 1 - v f ) , can be calculated, wherein Ef and &ngr;f are the Young's modulus and Poisson's ratio of the thin film, respectively.