Board Level Solder Joint Reliability Assessment Study of Megtron 6 Vs FR-4 Under Power Cycling and Thermal Cycling

Abstract

High frequency laminates like Nelco N4000–13, Isola FR408 and Panasonic Megtron 6 packages gained popularity among the industry due to better and improved electrical performances, Improved impedance control, low moisture absorption, good thermal management. High speed laminates are extensively used in high speed system-level interconnects like high speed network equipment, mainframes, IC testers and high frequency measuring instruments. When an electronic device is turned off and then turned on multiple times, it creates a loading condition called power cycling. The die is the only heat source causing non-uniform temperature distribution. In this paper, the solder joint reliability assessment of Megtron 6 boards are done using Finite element analysis (FEA) under two different loads power cycling and thermal cycling which act as a combined load. The reliability assessment is done to check stress distribution on PCB boards and solder joint. The life to failure is determined for Megtron 6 board package assembly. The mismatch in coefficient of thermal expansion (CTE) between components used in Megtron 6 and the non-uniform temperature distribution makes the package deform. Modeling of life prediction is usually conducted for Accelerated Thermal Cycling (ATC) condition, which assumes uniform temperature throughout the assembly. An assembly is also subjected to Power Cycling i.e., non-uniform temperature with the chip as the only source of heat generation. This analysis shows the performance of Megtron 6 package assembly under thermal and power cycle in combination and the stress distribution and plastic work for the package.