The analysis of leadframe packages reliability for automotive applications under thermal cycling

• Main Author: Dong, Shi
• Other Authors: Tang Xiaohong
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2025
• Subjects: Engineering; Lead frame reliability; Temperature cycling; FEA
• Online Access: https://hdl.handle.net/10356/182890
• Institution: Nanyang Technological University

Lead frame packaging technology is extensively employed in automotive and industrial applications due to its cost-effectiveness, strong thermal performance, and mechanical stability. Among such packages, Quad Flat Non-Lead (QFN) packages present critical challenges in board-level solder joint reliability, particularly under temperature cycling stress. This study focuses on analyzing the factors influencing the reliability of QFN solder joints during thermal cycling tests. Experimental data from thermal cycling tests on QFN packages were analyzed to identify key parameters affecting solder joint fatigue life. The results highlight that smaller package and die sizes, larger pad sizes, thinner PCBs, mold compounds with higher coefficients of thermal expansion (CTE), higher solder standoffs, and additional soldering on the center pad significantly enhance fatigue life. The observed maximum strain energy density (SED) during testing was concentrated at the top corners of peripheral solder joints, providing insights into the critical stress points. This analysis underscores the importance of package geometry, material properties, and test conditions in influencing QFN solder joint reliability. The findings offer valuable guidance for optimizing QFN designs to improve their performance and durability under thermal cycling conditions.