The Simulation Study on Internal Stress in Multilayer Thermistors during Soldering Process

Abstract

A new 3D finite element model to characterize the residual stress distribution in multilayer NTC thermistor during soldering process has been developed. During the soldering process, the effects of inner silver electrode number and lateral margin length on mechanical residual stress are studied. Throughout the weldbonding and heating process, the maximum and minimum principal stresses in the active region of the thermistor ceramic are not zero, which implies that most of the thermistor ceramic is not stress-free. Numerical results show that the increasing of the lateral margin length could effectively decrese the maximum tensile stress.