The Preparation And Study Of Conductive Fillers In Silver Slurry For Microelectronics Industry

With the development of microelectronic assembly industry to high density, high integration direction, conductive pastes tend to replace conventional tin lead solders in microelectronics as adhesive assembly in order to meet the needs of environmental protection and simple technique. As a result, conductive pastes have attracted more and more attention of researchers. At present, our country imports most of the products in the field, and the research on conductive pastes in domestic is serious insufficient. Therefore, to develop high performance conductive paste with independent intellectual property rights will be crucial to the development of China’s electronic industry. This thesis aimed at conductive silver pastes and conductive fillers for microelectronics industry.First of all, this thesis studied preliminarily the preparation of silver powders as traditional conductive fillers in silver pastes. The silver powders were prepared by chemical reduction method with silver nitrate as raw material, polyvinyl pyrrolidone(PVP) as dispersant, and ascorbic acid as a reducing agent. At room temperature, ascorbic acid solution drop slowly into the mixed solution of silver nitrate and dispersing agent, and the spherical silver powders with uniform particle size and good dispersion were obtained. By means of SEM, XRD, the particle size of the products were characterized, and the effects of dispersing agent, reducing agent and reaction temperature further studied on the particle size of silver nano-powders.Based on the preparation of well dispersed spherical silver powders, the self-made silver powders were used as conductive filler for conductive silver paste, with liquid bisphenol-A epoxy resin E-51 as matrix resin, methyl six hydrogen phthalic anhydride(MeHHPA) as curing agent, and 2-ethyl-4-methyl imidazole(2E4MZ) as curing catalyst. The influence of silver addition content and ball milling time on properties of conductive silver paste was studied to obtain the best formula and the technological conditions.In view of the excellent properties of graphene, the thesis will introduce graphene as the conductive fillers, to prepare graphene conductive paste and graphene composite conductive silver slurry. The influence of graphene addition amount on the properties of graphene conductive pastes was studied, and the performance is not satisfactory. The composite of graphene and silver particles was prepared as composite conductive fillers for a new conductive paste. Its performance changes with the adding quantity were studied, and excellent performances were obtained, which has high conducting performance while the tensile shear strength is maintained at a high level. As a result, the composite of graphene and silver particles is a kind of good conductive fillers for conductive paste.