Cohesive Zone Modeling of Delamination in Multilayer Composite Circuit Boards

A printed circuit board (PCB) mechanically supports and electrically connects microelectronic components. Multilayer PCBs include several conducting and insulating layers. Insulating layers are typically woven glass-fiber epoxy prepregs, while conducting layers consist of copper traces etched from copper foils. The epoxy of the adjacent prepreg layers fills the gaps where the copper was etched away, thereby creating copper–epoxy composite conducting layers. Mechanical loading may lead to PCB delamination at an interface between the adjacent conducting and insulating layers. A cohesive zone model (CZM) was developed to simulate the failure of PCBs assembled with microelectronic components. The CZM was calibrated using fracture tests of test specimens consisting of PCB substrates bonded with an epoxy adhesive. The model accurately predicted the fracture load and failure mode of the PCBs.

Keywords:

multilayer PCB , bending loading , delamination , cohesive zone modeling