Cracking Phenomena on Flexible-Rigid Interfaces in PWBs under Thermo Cycling Loading

Flexible printed circuit boards (fPCBs) have an important role in electronic product miniaturization due to their reduced thickness and ability to bend and adapt to various shapes. As with any new technology reliability should be assessed to guarantee quality of products that benefit from the additional features. Typical causes of cracking failure in electronic devices are related to mechanical stress, moisture, and heat from transportation and field use. Typically manufacturers carry out tests to evaluate the reliability of electronic components regarding these types of loads. Common tools used for this evaluation in early stages of design are finite element analysis and experimental laboratory tests. In this present work simulation models were proposed in order to develop tools for early stages of design. Thermomechanical tests were performed experimentally to assess reliability of parts and also provide information to evaluate the simulation models. The objective of this work is to develop simulation models for flexible printed circuit boards (fPCB) flex-rigid interfaces and to perform experimental tests in laboratory in order to evaluate the cracking phenomena when this device is submitted to thermal cycling.