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

ABSTRACT

The fragmentation of Cu₇₅Zr₂₅ amorphous films with varying film thickness $\left(h\right)$ 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 Cu₇₅Zr₂₅ amorphous films following the strain energy criterion. The adhesion energy between Cu₇₅Zr₂₅ film and polyimide is estimated to be of ∼ 6.5 J m⁻² based on the buckle geometry.

KEYWORDS:

• Cu-Zr amorphous films
• fragmentation
• adhesion energy
• film thickness effects

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant numbers 51621063, 51571157, 51625103, 51790482, 51761135031, 51722104, 51790484 and 51801146], the National Key Research and Development Program of China [grant number 2017YFB0702301], the 111 Project of China [grant number BP2018008] and China Postdoctoral Science Foundation [grant numbers 2016M590940, 2017T100744 and 2016M602811].