Deformation of multi-layerprinted circuit boards - Usage of the classical lamination theory formodelling PCB deformation

A high level of function integration requires the development of PCBs with increasing packaging complexity. To satisfy the requirements an asymmetric board lay-up is often unavoidable. An asymmetric board lay-up is the root cause of PCB deformation and originates problems with product specification and manufacturing process. The PCBs deform due to an unbalance of the board stiffness and the load situation around the center line. An analytical model is developed to estimate the deformation of a board early in the design process. The model is based on the classical lamination theory, obtained from the composite material domain. The classical lamination theory describes the behavior of loaded laminate by the properties of the individual layers. The boundary conditions used in the classical lamination theory are adjusted to meet the PCB manufacturing process circumstances and results in an analytical model suitable for modelling PCB deformation. Comparing the analytical results with the measured values, the conclusion that the model is suitable for modeling PCB deformation is valid.