Simulation analysis of the influence of test conditions on the bonding strength of PCB pads

In practice applications, the problem of printed circuit board (PCB) pad cratering is a common in BGA components. Pad cratering starts with the laminate. Cracks may start at the intersection of the copper pad and the laminate and gradually initiate at the prepreg and glass fiber, which can lead to PCB Pad cratering over time. These pads with pits may not fail immediately during early performance testing, but may initiate cracks during later service. In this paper, the finite element analysis method is used to study the stress and strain distribution of the pad when a single BGA pad is subjected to a certain tension, and the changes in the stress of each layer node during the process of pulling out the pad. and to simulate the bonding process of pad, adhesive layer and fiber interface. The pin pulling test of PCB material was carried out by 2D simulation with the cohesive method. Finally, it finds that the contact line area between pad edge and adhesive layer is subjected to the greatest pull force. Among the variables, the size of the pad has the greatest influence on the tensile force. The stress change process in the drawing process is the same as [1], which shows that the use of 2D simulation has a certain feasibility. The above conclusions can be used to optimize the design of PCB pads, and have a good reference value to the PCB designer.