Fabrication method of solid electrolytic capacitor using organic

Abstract

A fabrication method of a solid electrolytic capacitor is provided, which decreases the leakage current of a solid electrolytic capacitor without deterioration of ESR. This method is comprised of the steps (a) to (e). In the step (a), a capacitor body is formed by a valve metal, the body serving as an anode of the capacitor. In the step (b), an oxide layer of the valve metal is formed to cover a surface of the capacitor body by anodic oxidation, the oxide layer serving as a dielectric of the capacitor. In the step (c), a layer of an organic conducting polymer is formed on the oxide layer, the layer of the organic conducting polymer serving as a solid electrolyte of the capacitor. In the step (d), the capacitor body with the oxide layer and the layer of the organic conducting polymer is immersed in a reoxidation solution, the reoxidation solution containing a mixture of water and alcohol or a mixture of water and ketone as a solvent. In the step (e), a voltage is applied to the capacitor body to reoxidize the oxide layer in the reoxidation solution by anodic oxidation, thereby healing defects of the oxide layer. The amount of alcohol or ketone is preferably 30 vol % to 50 vol %.