Numerical Prediction of Socket Solder Joint Reliability during Shock

This paper proposes a simulation methodology to assess the risk in solder joint reliability (SJR) of Pin Grid Array (PGA)/ Land Grid Array (LGA) Socket during Mechanical shock. One of the main challenges in simulation is the complex socket/contact geometry convoluted with its massive number of degrees of freedom. This paper proposes a technique, Contact Isolation Method (CIM), to simplify the geometry so that it can be modeled with highly reduced degrees of freedom (DOFs) while still maintaining 90% of the in-plane and out-of-plane stiffness compared with the original structure. The Pin Grid Array 700 socket (PGA700) and Pin Grid Array 604 socket (PGA604) were used as case studies to demonstrate this methodology. A system model was completed for the PGA604 socket with a focus on its capability to assess SJR. A reasonable correlation between the modeling and experiment on the dynamic board strain demonstrates that this technique is viable. In addition, this paper verifies that the board strain is a proper metric for the risk assessment in SJR, and defines the optimal strain gauge location. The impact of the boundary conditions is also investigated.