Experimental determination of thin film adhesion using 4 point bending specimen

A specimen design having a 3-layered structure together with a loading device for the determination of thin film adhesion is presented. The specimen design has the advantage of requiring relatively simple preparation procedures and giving an accurate analytical model. The loading device is of 4 point bending type. The energy release rate for the specimen of the 3-layered structure is obtained explicitly in terms of the edge load and edge moment while the local loading phase angle is evaluated via the J-based mutual integral method. The interfacial fracture toughness as a measure of adhesion for the Si/Cu/epoxy system is determined experimentally over a range of phase angles using the proposed method.