Preparation And Properties Of Porous And Low Dielectric Polyimide Films

With the progress of Chip manufacturing technology, low dielectric constant and insulating Mterials used as a dielectric medium between interconnection wires are in the need.Unique main chain structure makes polyimide have excellent physical and chemical properties, including thermal stability,chemical stability,low dielectric performance and high insulation performance, making it a potential of the dielectric material, but its dielectric performance will not meet current demand. In this paper, we reduced the dielectric constant of polyimide film by introducing porosity,and made porous polyimide films having different porosity.Through the composite of graphene oxide and polyimide to improve the mechanical properties of porous polyimide membrane, the effect of graphene oxide have on the dielectric performance of the porous membrane were studied.Polyamide acid was synthesized using six different methods, the best way to the synthesis was determined by measuring molecular weight of the products.Respectively using three methods of imide reaction, thermal imidization, catalytic imidization and chemical imidization,to explore the synthesis conditions of polyimide.We discovered that tertiary amine used as catalyst can significantly reduce the imidization temperature. Acetic anhydride used as dehydrating agent and triethylamine used as catalyst can realize completely imidization of polyamide acid.The monodisperse silica microspheres prepared were used as fillers. The composite membrane prepared by in-situ polymerization method,The effects of the microsphere surface modification have on the tensile properties and dielectric properties of composite membrane were analyzed.The silicon dioxide was ethed in hydrofluoric acid to get porous membrane.By characterizing the mechanical properties and dielectric properties of porous membrane, we fond tha with the increasing of porosity, the tensile strength of porous membrane is lower and the dielectric constant lower linearly.Referencing improved Hummers method graphene oxide was prepared by the oxidation of graphene.It can be dispersed in water homogeneously and steadyly. Graphene oxide /polyimide composite films were prepared by in-situ polymerization. The effects of the graphene oxide surface modification have on the tensile properties and dielectric properties of composite membrane were analyzed. Porous composite membranes containing graphene oxide were Also prepared.when the porosity is 8.6% and graphene oxide content is 1 wt %, the dielectric constant of porous co mposite membrane was 2.01.