Electrostatic Propensity and Bleed-Off Characteristics of Composite Materials

摘要

A class of composites, popularly known as static dissipative materials, is widely used in semiconductor manfacturing and/or handling situations, as surface-finishes, packing media, etc. to prevent excessive triboelectric charge accumulation upon semiconductor devices, lest device failure may occur due to electrical overstressing. Presently, a mixture model to predict the effective electrostatic propensity of a two-phase composite formed by a dispersal of conducting (and shaped) inclusions in an insulating medium is developed on the basis of stochastical considerations. A closed-form expression to determine optimum design-value for the volume-fraction of conducting inclusions so as to get a minimum static bleed-off time, is derived. The optimization is done with the constraints imposed on the electrical resistivity of the composite by certain practical considerations.