Polymeric coatings have been used in many ways from automobile paints to package coatings for integrated circuits. It is important to understand the mechanical properties of coatings in order to ensure fulfilling their designed functions. To measure these properties, in situ measurement techniques are desirable since these techniques measure the mechanical properties of coatings in the presence of the correct residual stress. In addition, the coatings most commonly used are multi-layer structures, a fact which increases the difficulty of the mechanical analysis. At present, the in situ mechanical behavior of multi-layer coatings has not been well characterized, and very few researchers have reported a satisfactory way to analyze multi-layer problems.