Quantitative investigation of the adhesion strength between an SU‐8 photoresist and a metal substrate by scratch tests

Abstract

ABSTRACTDuring the manufacturing process of metal microstructures and microdevices by SU‐8 ultraviolet‐lithographie, galanoformung and abformung (UV–LIGA) technology, interfacial delamination and bond failure are common because of the poor adhesion strength between the SU‐8 photoresist and the metal substrate. In this study, a scratch method was used to measure the adhesion strength between the SU‐8 and the metal substrate. A simulation of a scratch test process was accomplished on the basis of the finite element method, and a modified empirical formula that accounted for local horizontal stress was deduced by a dimensional analysis method. The good agreement among the calculated formula, corresponding simulant, and experimental results showed the validity of the modified empirical formula. Interfacial adhesion work was also obtained to characterize the interfacial adhesion properties. This study provided a theoretical basis for quantitatively estimating the interfacial adhesion strength and a theoretical foundation for improving the interfacial adhesion properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41108.