Underfill Adhesive Cracking and Solder Joints Failure Risk Analysis in Microwave Modules Based on Cohesive-Element Modeling

The miniaturization and increased functionality of electronic devices necessitate advanced materials and assembly techniques to ensure reliability. Underfill adhesives are critical in distributing thermal and mechanical stresses away from solder joints, thus extending the operational life of electronic assemblies. However, under extreme thermal conditions, the risk of adhesive cracking poses a significant threat to the durability and reliability of these systems. Understanding the failure mechanisms of underfill adhesives and their impact on solder joint integrity is crucial for the development of more resilient electronic modules. In this study, we construct a detailed finite element model comprising a microwave module, underfill adhesive, solder points, and PCB. This model facilitates a comprehensive analysis under high-temperature conditions (125 °C), focusing on the initiation and progression of adhesive cracking and its influence on solder joint performance. By examining various scenarios of adhesive bonding strengths, we identify the critical parameters influencing adhesive failure and solder joint degradation. Our findings reveal a quantifiable correlation between underfill adhesive bonding strength and solder joint failure risk, emphasizing the importance of optimizing adhesive properties to mitigate failure risks under thermal stress. This correlation provides invaluable insights for the design and selection of underfill materials in microwave module assemblies.