Study On The Performance Adjustment And Preparation Technology Of SiO₂/GF Filled PTFE Composite Substrate

With the development of electronic information industry,the dielectric constant,dielectric loss,the coefficient of thermal expansion,the rate of water absorption and the stability of dielectric constant in the temperature changing environment are more and more demanding.And polytetrafluoroethylene?PTFE?is a resin material with excellent microwave dielectric properties.In this paper,using the polytetrafluoroethylene?PTFE?as the matrix,amorphous fused silica?SiO₂?and chopped glass fiber?GF?as the main filler,designed to produce a low dielectric loss,fine thermal stability composite substrate material which can be used in the high frequency band?10 GHz?.Based on the study on the composition and preparation process of SiO₂ / GF-based PTFE composites,a mature and reliable preparation method was obtained,and the dielectric constant,the coefficient of thermal expansion,the water absorption can be calculated.After this work,a composite substrate with a certain range of dielectric constant,low dielectric loss,low water absorption and low thermal expansion coefficient can be manufactured,the specific work is as follows:1.The study on preparation process:?a?Find out high-speed dispersion mixing process make the system's dispersion better,improve substrate density,and the dielectric properties,through comparing the ball milling process with the high-speed dispersion mixing process.?b?Find out the rolling method can improve the substrate density,dielectric properties and water absorption,through comparing dry powder molding method with the rolling method.?C?Find out that sintering the substrate at370 ? with 30 MPa,120min is more rational,through the study on heat-pressing pressure,temperature and holding time.The study on the content of SiO₂/GF:?a?As the SiO₂ content increasing,the dielectric constant increases first and then decreases,and reaches the maximum when the total content of SiO₂ / GF is 66 wt.%,and the dielectric loss increases first and then increases;Water absorption,porosity is monotonically increased.?b?As the GF content increasing,the dielectric constant increases;the dielectric loss increases first and then increases;the water absorption increases monotonously.?c?As the GF content increasing,the dielectric constant increased,dielectric loss increased,when the SiO₂/GF total content is constant.?d?When GF is added,the thermal expansion properties of theproduct are significantly reduced,with the further increase in GF content,the thermal expansion coefficient of the product increases slightly,and then tend to be stable.