Development of PCB design guide and PCB deformation simulation tool for slim PCB quality and reliability

In this paper, major concerns from the use of slim PCB are considered and several efforts to solve the trouble are introduced. The critical phenomena by the application of slim PCB are large warpage generated during reflow (soldering) process and large deformation of IC package by external impact environment. Those are due to the low bending rigidity according to the decrease of thickness, and increase the SMD process defect and decrease the drop reliability of IC package mounted on PCB. To solve those issues, various experiment and simulation are performed. First, PCB internal layer material to resist high temperature is investigated. To predict large warpage during reflow process, PCB thermo-mechanical simulation tool is also developed. To increase drop reliability of BGA package, robust design guide for drop impact condition is studied. Last, PCB pad surface finish recently developed is introduced to find the possibility to increase solder joint strength. Based on the material, process and reliability approaches, current PCB deformation level for main board is shown and the optimal PCB design for smaller warpage and larger reliability is obtained.