Extracting Material Properties by Metal Thin Film Thickness Using Tape Test-Based Wrinkle Structure

Abstract

We present a simple method to measure metal thin-film material properties depending on thickness using wrinkle structures which occurred by scotch-tape test for commercial adhesion evaluation method. After metal thin-film (Al and Au - a thickness of 150 and 300 nm) patterning on PSPI substrate using photolithography and ICP-RIE, metal thin-film transfer was performed by scotch-tape test. Metal thin-film wrinkle structures have been formed due to mechanical mismatch between the two materials. The wrinkle structures have been characterized with an optical microscope and SEM images in order to measure the wavelength and amplitude of wrinkle structure and then they are compared with FEM (Finite Element Method) buckling simulation results for material properties extraction. The relationship between wavelength and elastic modulus resulted from FEM modeling and simulation. As a result, it was confirmed that Young’s modulus of metal thin-film has substantial dependence on its thicknesses in the nano-scale range.