Dielectric studies of solder paste fluxes and applications tono-clean paste formulations

摘要

Ionic mobility is monitored using a 12.5-μm interdigitatedelectrode to monitor conductivity, loss factor, and permittivity ofsolder flux, solder vehicle, and solder residue. Maximum ionic mobilityis achieved at the temperature for minimum viscosity (87° C) andother increases can be seen at the melting point of abietic acid. Ionicmobility is shown to be dependent on the amount of plasticizer in theresin material which is correlated to the material's glass transitionand viscosity. Differences in the particle size of metal particles inneat solder pastes have been correlated to the permittivity in thissystem. Measurements were made using a ceramic sensor with a 10-milinterdigitated electrode pattern. A linear relationship between particlesize/relative surface area of the metal particles and permittivity hasbeen observed. Flocculation has been observed by this method in pastescontaining small particle size metal particles