Characterization and reliability of conductive ink/polymer filled microvias

The robustness and reliability of conductive polymer materials for multilayer laminate substrate interconnection has evolved from electronic packaging applications in rather benign environments to applications that endure the harshest automotive environments, i.e. underhood and on-engine. This extended abstract serves as an introductory survey of conductive ink/polymer filled microvia materials, process, and reliability development. It characterizes in microstructural detail several conductive ink systems used to fill microvias, describes multilayer laminate substrate fabrication and interconnection approaches along with some related process issues. It highlights the design advantages of these constructions and summarizes results of bare board reliability testing and the requirements for demanding automotive environments. The bulk resistivity of these conductive ink materials range from 35 to 300 (/spl mu//spl Omega/ cm) depending on the degree of contiguity of the metal phases. The adhesion and/or metallurgical bonding to opposing layer-to-layer circuit pads is critical in obtaining suitable reliability and low contact resistance of the interconnection. The utilization of these interconnection methods for mixed density substrate applications as well as multilayer laminate substrate approaches will be briefly discussed.