Abstract
A new technique for producing a sharp pre-crack between a thin film and a substrate is developed utilizing the difference in interface strength. This technique is applied to a sputtered copper (Cu) thin film on silicon (Si) substrate. A vacuum-evaporated Cu thin film, which has poor adhesion to Si, is inserted between the sputtered Cu thin film and the Si substrate as a release layer. The release layer debonds from the Si substrate at very low load, and the process successfully introduces the sharp pre-crack along the interface. Using the specimen, the interface fracture toughness test is conducted and the critical strain energy release rate, G_C, is evaluated as about 1.78 J/m^2 for the sputtered Cu/Si interface.