AN ANALYTICAL APPROACH TO BGA COMPONENTS IN RANDOM VIBRATION ENVIRONMENTS Milan J Lucic, MANE 6980 Engineering Project

Project Overview  BGA components are integral to the design of advanced electronic systems like your cell phone, or computer  Aerospace electronic controllers use BGA components for processors or programmable gate arrays  Reliability of these components greatly reduced by mechanical vibration environments in Aircraft  Green Compliance (ROHS) driving electronic components to use lead free solder and components

Problem Statement  Goal is to study the stress and high cycle fatigue of BGA components on card rack style circuit boards  Random vibration from RTCA DO-160F for fixed wing aircraft  Taking in account of several variables:  BGA position on board  Lead vs. Lead-free solder (also lead free components)  Random vibration level  Component will be modeled after the ACTEL 484 PBGA commonly used in the aerospace industry

Methodology and Approach  Accurately model the ACTEL 484 PBGA with 3-D hex elements (balls and solder joint), and 2-D Shell elements (PCB and component body)  Using NX7.5 Advanced simulation for Pre-Processing and MSC PATRAN/MD NASTRAN as the post processor and solver  PATRAN Random utility to solve for frequency response (Mode Shapes), displacements, and RMS stresses  Using hand calculations, solve for the Miner’s Damage Index of electrical components and the high cycle fatigue of the BGA components.

Expected Outcomes  To develop a better understanding of lead vs. lead free BGA components used in common Aerospace environments  Correlate data with actual industry test data to refine future models  Greatly reduce risks early in the design phase  Eliminate the need for development testing of BGA components (expensive and time consuming)  Generate plots of high cycle fatigue life for lead vs. lead-free BGA components

Project Progress-FEA Model BGA Model ACTEL 484 PGA Pin Grid Snapshot Solder Ball and Solder Joint FEM

Project Progress-FEA Model Lower Left CornerCenter Left SideCenter Position

Project Schedule  Week 1: Develop Project Definition  Week 2: Preliminary Project Proposal  Week 3: Project Proposal  Week 4: FEA Model Development/Research  Week 5: Random Analysis/Model Refinement  Week 6: Random Analysis/Model Optimization  Week 7: Random Analysis/Model Optimization, First Progress Report  Week 8: MDI Calculations/Random Analysis  Week 9: Business Trip, out of the country.  Week 10: Post Processing, Second Progress Report  Week 11: Post Processing (extra time for model refinement)  Week 12: Final Report Draft  Week 13: Final Report Draft  Week 14: Final Report