Influence of Substrate on Microvia Structures in Printed Circuit Boards During Reflow

The automotive industry’s increasing dependence on compact electronic packages requires printed circuit boards with robust microvia interconnections. With a focus on minimizing failure rates and reducing costs, automotive manufacturers require that microvia reliability have zero failures. To achieve this, the automotive industry requires identification and understanding of the uncontrollable factors related to substrates that influence microvias during the reflow process. However, conventional studies not accounting for the non-uniform nature of substrates fail to capture the real-time impact of composite substrates on microvias during reflow, highlighting the need for comprehensive substrate analysis. In this paper, we present a detailed finite element model substrate layer to analyze the influence of the substrate material on microvia structures using the design of experiment technique using the Taguchi method. The results showed that the uneven distribution of fiber and resin ratios within the substrate layer affects the microvia structures. Microvias in resin-rich areas are more susceptible to failure with 33% higher stresses than those present in fiber-rich areas. Furthermore, printed circuit board substrate is characterized into different zones based on microvia failure risk levels.