Mechanical Stress and Deformation of SMT Components During Temperature Cycling and PCB Bending

Bending tests and temperature cycle tests are very common methods for predicting the reliability of components soldered on PCBs or substrates. Sensitive SMD constructions such as chips with ball grid array mounting or multilayer ceramic chipcapacitors (MLCC) are often a major issue due to their “flex cracking” problems. This paper describes the real behavior of deformation at temperature cycling and PCB bending ofchip components (body size 0603). By using the piezoresistive effect in thick film resistors, the effects of stress on the alumina body can be determined anddescribed for the whole temperature range of interest.