Properties of Ag Thick Films Fabricated by Using Low Temperature Curable Ag Pastes

Abstract

Properties of Ag thick films fabricated by using low temperature curable silver pastes were investigated. Ag pastes were consisted of polymer resins and silver powders. Ag pastes were used for conductive or fixing materials between board and various electrical and electronic devices. Low temperature curable Ag pastes have some advantages over high temperature curable types. In cases of chip mounting, soldering properties were required for screen printed Ag thick films. In this study, four types of Ag pastes were fabricated with different compositions. Screen printed Ag thick films on alumina substrates were fabricated at various curing temperatures and times. Thickness, resistivity, adhesive strength and solderability of fabricated Ag thick films were characterized. Finally, Ag thick films produced using Ag pastes, sample A and B, cured at <TEX>$150^{\circ}C$</TEX> for longer than 6 h and <TEX>$180^{\circ}C$</TEX> for longer than 2 h, and <TEX>$150^{\circ}C$</TEX> for longer than 1 h and <TEX>$180^{\circ}C$</TEX> for 1 h, respectively, showed low resistivities of <TEX>$10^{-4}$</TEX> <TEX>$∼10^{-5}$</TEX> Ωcm and good adhesive strength of 1∼5 Mpa. Soldering properties of those Ag thick films with curing temperatures at solder of 62Sn/36Pb/3Ag were also investigated.