ABSTRACT
Adhesion testing was done using a scratch tester that had a balanced lever arm with a diamond stylus of 0.2 mm radius and a load platform above the stylus. During the test, the stage with the specimen had a translational motion at a constant speed of 27 μ ιη /s. A strain gauge rigidly attached to the load platform measured the applied tangential forces. The scratch tests done on a laser treated film showed no de-adhesion from the substrate after applying a load of 400 g while an as-deposited film showed clear signs of removal at the root of the scratch at a normal load of only 200 g. The shear stresses where no de-adhesion was detected were 0.65 GPa and 0.21 GPa for the laser-treated and for the as-deposited films, respectively. The optical micrograph of Fig. 2 shows a scratch made with a 100 g normal load on a copper film deposited on sapphire, the right portion of which was irradiated (lighter region). The scratch goes from the non-irradiated portion (darker region) to the irradiated part (lighter region). Ripples indicating de-adhesion can be seen in the unirradiated region. This effect was further illustrated by the profiles of the groove taken in the non-irradiated region (left) and the irradiated part (right).
