Development of low viscosity, high dielectric constant (k) polymers for integral passive applications

Abstract

The integration of passive components (resistors, capacitors, inductors) into printed wiring boards (PWBs) has become a very significant part of electronic packaging technology. The biggest advantages of integrating passive components into a substrate are reduced assembly costs, minimized PWB real estates, reduced component dimensions, and improved electrical performance. One of the challenges of incorporating passives into a PWB is choosing a suitable material that satisfies both electrical and reliability needs. This research seeks to develop high dielectric constant (k) materials for integral capacitors and integral decoupling capacitors. More specifically, the goal of this work is to develop low viscosity, high k polymers for use in conjunction with high k ceramic materials, such as lead magnesium niobate, to form high k polymer-ceramic composites. Polymers with viscosity values ranging from 0.13 to 0.15 Pa/spl middot/s were formulated and characterized by differential scanning calorimetry (DSC), dielectric analysis (DEA), and rheology. The polymers were mixed in different volume percentages with lead magnesium niobate-lead titanate (PMN-PT) ceramic powder by ball milling. DSC and DEA were used to characterize this composite material. Several methods for increasing dielectric constant were identified and implemented. Prototype capacitors were fabricated in order to measure k values for the composite materials. Dielectric constant values as high as 62 were achieved with samples containing relatively low volume percentages of PMN-PT ceramic powder.