Graduation Semester and Year

2017

Language

English

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Dereje Agonafer

Abstract

Quad Flat No-lead package (QFN) is one of the most cutting-edge technologies emerged in the market, exhibiting high performance and efficiency with unparalleled cost effectiveness. QFN, a leadless package, is an ideal choice for applications where size, weight thermal and electrical characteristics are critical, particularly in mobile and handheld devices. Applications like automotive, defense and high current circuits require the package to be mounted on thick printed circuit boards (PCB). The motivation of this work is to understand the effect of design variations of solder joints affecting reliability and optimize the solder package to improve reliability for application on different PCBs. Initially, The material properties of the PCBs were determined using Thermal Mechanical Analyzer (TMA), Dynamic Mechanical Analyzer (DMA). The PCBs were then cross sectioned to find the layer composition and Copper content in the boards. Different designs of solder joints were made using ANSYS SpaceClaim. The quarter models of boards with the different solder designs were then subjected to Accelerated Thermal Cycling Tests, to study stresses generated on the solder joints and variation in Plastic work. A comparative study was performed on obtained results for different solder designs and on different PCB boards to propose the optimum solder design to reduce solder damage and increased life in QFN assemblies.

Keywords

QFN, Reliability, Solder

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

Download

Share

COinS