Study Of PCB Substrate Thermal Property Based On Finite Element And Synthesis Of Ultrafine Copper Powder

With the development of electronic product trend to be miniaturization, highfrequency and multi-function, printed circuit board (PCB) industry worked as thesecondary package of electronic product also faces the challenges of high density,highreliability and high transmission signal digitization, the industry has begun to explorenew technology and process to meet these challenges. To develop substrate with goodheat dissipation performance and fabricate conducting lines with directly printing aretwo areas which have important practical value through PCB industry. The substratewith good heat dissipation performance could effectively reduce the failure of electronicproducts due to high temperature. Fabricating conducting circuit with printed electronictechnology would avoid the waste of materials and save the cost. In this paper, thethermal proterty of the substrate and ultrafine copper powder used for fabricatingconducting line were studied.In this paper, the software ANSYS was used to analysis the factors which affect thethermal property of the substrate based on finite element method and the heat transferscience. The temperature field distribution of substrate was obtained and a newsubstrate with embedded aluminum thermal conducting layer in was proposed. It wasfound that embedding aluminum thermal conducting layer in substrate could effectivelyreduce the working temperature of the components, the heat capacity of the substratewill also get greatly improved even the thickness of the thermally conducting layer wasvery thin. The temperature field distribution of substrate was achieved with differentthickness and embedding position of heat conducting layer, the influence of heatdissipation performance of substrate with different conducting layer thickness andembedding position were discussed. The heat conduction along the Z axis direction wasalso studied. In addition, the impact of substrate heat dissipation performance withdifferent component and circuit layout were simply analyzed in the design point.In this paper, the ultrafine copper powder was synthesized in the presence ofenvironment-friendly L-ascorbic acid as the reducing agent at room temperature. The product was characterized with many methods. The influence of PVP concentration,dropwise rate, L-ascorbic acid concentration, reaction time and the system viscosity onthe morphology and particle size of product were studied, and the proper mechanismwas proposed. The ultrafine copper powder was synthesized with the two-step methodusing L-ascorbic acid as the reducing agent, which was also characterized. Theinfluence of reaction temperature on product was discussed. Based on the orthogonaldesign method, the reaction conditions was optimized, using the optimized parametersthe ultrafine copper powder with the particle size range from80to120nm was obtained.The ultrafine copper powder with the particle size range from60to100nm wasachieved in the presence of sodium hypophosphite as reducing agent in the diethyleneglycol solvent. The influence of PVP and reaction temperature on the product wasstudied. A rod structure of ultrafine copper powder was obtained by changing thevolume ratio of copper sulfate aqueous solution and diethylene glycol solvent.