Development of High Reliability Via on IVH (VONI) for High Density Interconnect Circuit Boards

Via on interstitial via hole (VONI) technique is a complex set of technologies for blind and buried vias in traditional sequential lamination cycles with external layers, and micro via holes (MVH) for true high-density packaging. However, when VONI is repeatedly subjected to thermal stress, the interstitial via hole (IVH) in its structure often creates problems such as IVH barrel cracks, and layer-layer delamination. To solve VONI's reliability problems, such as IVH barrel crack and layer-layer delamination, the authors have investigated the relationship between the CTE difference and the effect of moisture. Through using different types of plugging inks, it was clearly indicated that delamination was related to the chemical properties of the plugging inks. For example delamination was dominated by the inks property of water adsorption, which induced vapor pressure when it undergoes thermal shock testing. The authors have solved the delamination problem by reducing the ratio of water adsorption in the plugging ink.