Numerical investigation of the process of embedding components into Printed Circuit Boards

Abstract

During laminating of Printed Circuit Boards (PCB) bending stresses in the embedded components can be generated due to pressure induced by the resin flow over them, which can lead to their fracture. In addition, the cooling of the PCB after curing of the resin can be even more important for the loading of the component. Here, the different coefficients of thermal expansion of the involved materials (i.e. pre-pregs, glass, resin, ceramic component) are the key parameters that can introduce residual stresses in the system. In this work the crucial steps in the integration of ceramic components into multi-layer PCBs have been investigated in terms of the mechanical stresses in the embedded components. In order to find the key parameters, the main process steps (i.e. laminating and cooling from the curing temperature) have been assessed using simple analytical and numerical FE models. The geometry used consists of several pre-preg layers (modelled as glass and resin layers) embedding a ceramic component. The stresses in the components are analysed and the most important parameters in terms of geometry and material properties are discussed.