Fiducial mark and nanocrack zone formation during thinfilm delamination

Abstract

A bstractCarbon ®ducial marks are formed during thin-®lm local delamination processes induced either by superlayer indentation forming circular blisters, or by residual stress relief through telephone cord blister formation. Hydrocarbons are sucked into the crack tip during the delamination process, outlining the cracktip-opening angle, which can be used to back calculate thin-®lm adhesion using either elastic or plastic analyses presented here. Fiducial marks have been observed in two di erent thin-®lm systems, namely Cu/SiO2 and TiWxNy/ GaAs. Cu/SiO2 delamination blisters have been cross-sectioned using the focused-ion-beam method, and high-resolution scanning electron microscopy of the cross-sections revealed crack renucleation ahead of the original crack tip. This is attributed to the stress redistribution process due to the dislocation shielding mechanism. At stress intensity levels of 0.33 MPa m 1/2 , it is found that four emitted dislocations can account for crack arrest, with renucleation of 100 nm sized nanocracks dependent on the antishielding stresses.

Micro-fluidic applications of telephone cord delamination blisters

“…In this case, water is transported with the advance of the crack tip at about 10 lam/minute, although higher propagation rates, up to several microns per second were observed in other samples. It has been previously shown that interfacial cracks in thin films act as a vacuum cleaner, collecting contaminants from the atmosphere, thus reducing the energy of the newly-formed fracture surfaces [ 11,12]. In this case, crack is acting like a pump, transporting fluid along with the blister propagation, and water droplets are seen on the Si substrate in Figure 3.…”