固体電解質膜を用いた銅の固相電析法のメカニズム解析

Efficient electrodeposition can be accomplished using solid electrolyte deposition（SED）with a cation exchange membrane as an electrolyte because the electric field imposed on the electrolyte membrane can control the mass transfer of metallic ions. Salient benefits of SED include the following: （1）Pattern plating can be conducted easily. The handling of an electrochemical cell is extremely simple because of its solid electrolyte usage. （2）Post-treatment of the electrode is unnecessary because the solid electrolyte contacting the electrode surface can be removed after electrodeposition. （3）High-rated plating can be expected because the driving force of the mass transfer of the reactants is expected to be migration. To verify those benefits, electrochemical measurements were conducted. Current-potential curves show the current density in the SED to be higher than that obtained using copper electrodeposition in the same concentration of CuSO4 solution as that for the SED. Moreover, the patterning was easy. Post-treatment was unnecessary because copper was deposited only on the substrate contacted with the solid electrolyte. We propose a mass transfer mechanism that occurs during SED processing using a solid electrolyte. The relation between overvoltage and the current density during SED is explained clearly by the mechanism.