PURPOSE: To improve the life stability of radio frequency characteristics of a solid electrolytic capacitor employing zinc dioxide as solid electrolyte by a method wherein a lead dioxide layer and a manganese dioxide layer are successively formed as electro lyte layers on a base metal anode substrate coated with a dielectric oxide film layer and a cathode lead out means is provided on the upper surface.

CONSTITUTION: A lead dioxide layer and a manganese dioxide layer formed by an electrochemical means are successively formed as electrolyte layers on a base metal anode substrate whose surface is coated with a dielectric oxide film layer and further a cathode lead out means is provided on the upper surface. For instance, a dielectric oxide film layer is formed on an etched and expanded Al foil by an anode oxidization treatment and a lead wire for anode lead out is connected to the end part to form an anode substrate and the anode substrate is immersed in the mixture of lead acetate solution and ammonium persulfate solution to form the lead dioxide layer chemically at 70 °C. After the substrate is washed, electrolysis is carried out in manganese sulfate solution to deposit manganese dioxide. Then the substrate is washed and dried and conductive paste is applied to form a cathode lead out layer and a solid electrolytic capacitor is completed.