Data-Mining of Factors Affecting Circuit Connection Reliability on Laser-Drilled Micro Blind via Holes in Multi-Layer PWBs

The purpose of the present study is to analyze the circuit connection reliability of printed wiring boards (PWBs) in relation to the thermal stresses obtained by FEM and to apply the FEM data to a data-mining method in order to clarify the factors that influence the thermal stress of the copper plating on the drilled hole walls. The following are the conclusions obtained herein: (1) Decreasing the thickness of the build-up layer is effective in reducing the thermal stress of the copper plating. (2) Using the data-mining method, new factors that were hidden in the data, such as the coefficient of thermal expansion in the Z direction, were revealed, despite the presence of other complex factors.