Development of a Microvia Fatigue Life Model Using a Response Surface Method

High-density interconnect printed-circuit boards and substrates are widely used for high-end electronics to meet the demand for greater input/output density and a smaller footprint area. Microvias as electrical interconnections between circuit layers have a much smaller scale (no larger than 150 μm in diameter) compared to conventional plated-through holes, and require a different fabrication process that introduces unique reliability challenges. This paper identifies factors that affect microvia fatigue life and presents a design of experiments to quantify the effects of those factors on microvia life in terms of cycles to failure. A regression life prediction model is formulated to account for the significant design, material, and defect parameters.