Optimal Shock Pulse in a Drop Test Simulation of Standardized Board for Uniform Shock Response

Abstract

Boardlevel physical test performance of CSP/BGA packages need in depth characterization of loading parameters and material behavioral properties. In recent years, many calibration methods were adopted by the researchers and industries to improvise solder joint performances of packages. Effective and uniform board response is one of the critical challenges in developing test board to qualify package components for solder joint reliability qualification. In this paper, an improvised board type alternative to standard Joint Electron Device Engineering Council (JEDEC) board is developed for uniform stress/strain response. An axis symmetrical board is chosen in comparison to the current JEDEC board. The effectiveness of the two boards are compared with each other under extreme banding under controlled drop test simulation. The uniform stress–stain distribution is recorded maintaining the noring phenomenon by selecting optimal shock pulse parameters. Selected impact/shock pulse is decided by identifying the maximum impact energy absorbed by the board during the drop event. Board surface strain and stress data are captured 1–2 mm away near the components are quantified for higher strain rate. The board local strain rate on the board surface is recorded at a selected timestep to quantify the dynamic stresses along the component side surface on the board. The simulation is performed by using ANSYS software using implicit method. Both linear SOLID45 and quadratic SOLID95 elements are used to compare and correlate the results. Close forms of results were correlated with the previous theoretical results.