Acoustic detection of micro-cracks in small electronic devices

We demonstrate the feasibility of in-situ acoustic detection of micro-cracks in small electronic devices. Applying precisely controlled damage to test vehicles using a nanoindenter, we record brittle fracture of thin layers by means of an ultra-sound piezo sensor, which is able to detect micro-cracks in the moment they emerge. This robustness test does not require further preparation effort that may induce additional stress to a sample or modify it physically, inhibiting unambiguous failure analysis. With regard to its applicability and limitations, we put acoustic emission into context with standard ex-situ experimental procedures for crack characterization in micro-electronic structures.