Benchmarking four point bend adhesion testing: The effect of test parameters on adhesion energy

Abstract

The four-point bend test method has been widely used to quantify the adhesion energy of interfaces in multilayer thin film stacks. However, the adhesion energy of an interface (Gc) may be effected by variances in the specimen preparation method and test procedure. In the present study, a less time consuming method of specimen preparation that involved cleaving (DPN-free method) rather than dicing of specimen was found to offer a 90% test success rate with high accuracy and repeatability. The epoxy curing temperature and time were minor factors affecting Gc and their effect was within the test standard deviation of 0.3 J/m 2. For a higher Gc interface, the epoxy thickness was found to result in a 20% increase in measured Gc as the bond layer was increased from 7 to 50 μm. The measured value of Gc also increased by 20% as the displacement rate was increased from 0.05 μm/s to 0.5 μm/s. The notch or scribe used to initiate the crack was found in one stack structure to have an effect on the interface that debonded. The delamination interface can be modulated through control of the notching step during sample preparation. © 2005 American Institute of Physics.