Microscale oscillating crack propagation in silicon nitride thin films

Controlled microscale (<50 mu m) wavy cracks in silicon nitride thin films have been produced through a simple heating process. The crack paths were controlled by metal patterns under the silicon nitride thin films. Wavy crack characteristics were investigated by changing the metal, metal linewidths, metal thickness, and silicon nitride thickness. We discuss the differences in the characteristics and mechanisms of propagation of wavy cracks formed due to differential thermal expansion and those that result from thermal gradients. (C) 2010 American Institute of Physics. [doi:10.1063/1.3480408]