Evaluation of interfacial strength of copper thin film on printed circuit board with micro cutting system

The purpose of this paper is to develop the evaluation method of interfacial strengths with a micro cutting system. The interfacial strength of thin films is crucial for the reliability assessment of electronics packages and MEMS devices. There have been a lot of experimental and theoretical studies about the measurement of interfacial strengths. However, it is still under developing stages, because it is quite difficult to measure it quantitatively for micro-and nano-thickness films. Recently, SAICAS(Surface and Interfacial Cutting Analysis System) has been developed and used for the evaluation of the mechanical properties in micro-and nano-thickness films. In this paper, we developed the theoretical model of SAICAS micro cutting tests and proposed the evaluation method of interfacial strength for thin films systems. The proposed method was applied to copper thin films on printed circuit boards and compared with 90° peel tests. The results show that the proposed method can exclude the plastic and friction dissipation energies during the SAICAS tests and quantitatively evaluate the interfacial strength.