Fragmentation and adhesion properties of Cu-Zr amorphous thin films on polyimide substrates

The fragmentation of Cu ₇₅ Zr ₂₅ amorphous films with varying film thickness (h) on polyimide substrates has been investigated by uniaxial tensile testing, in combination with in situ electrical resistivity measurements, optical microscopy and atomic force microscopy. It is revealed that the cracking strain monotonically increases as h decreases, which can be attributed to the constraint effect of film thickness on shear band formation and the columnar structures in the thicker films. Similarly, the buckling strain also increases with decreasing h, with the delamination of Cu ₇₅ Zr ₂₅ amorphous films following the strain energy criterion. The adhesion energy between Cu ₇₅ Zr ₂₅ film and polyimide is estimated to be of ∼ 6.5 J m ⁻² based on the buckle geometry.