METHOD OF PRODUCING METAL FILM

To provide a method of producing a metal film capable of producing a metal film having a uniform thickness across the whole film, even if the area of a solid electrolyte membrane is large and the ratio of the area of a produced film relative to the area of a substrate (a coverage factor) is large.SOLUTION: There is provided a method of producing a film comprising a step of arranging a solid electrolytic membrane 5 between an anode 1 and a cathode 2, a step of arranging an aqueous solution L comprising a metal ion between the anode 1 and the solid electrolytic membrane 5, a step of applying a voltage between the anode 1 and the cathode 2, and a step of pressurizing the aqueous solution L to apply a pressure force P resulting from the liquid pressure of the aqueous solution L onto the solid electrolytic membrane 5, to produce a metal film C constituted of the metal of the metal ion on the surface of a substrate 6, with the upper limit value and the lower limit value of a mean pressure Y of the pressure force P set between an upper limit value and a lower limit value defined by the following formulae using a coverage factor X; the upper limit value: Yup≤2.5, and the lower limit value: Yud=(2.5×10-8)X5-(4×10-6)X4+0.0002X3-0.0065X2+0.079X+1.8, if the coverage factor X is greater than 0% and equal to or lower than 67%, and if the coverage factor X is greater than 67% and equal to or lower than 100%, Yud=0.5.SELECTED DRAWING: Figure 2 【課題】固体電解質膜の面積が大きな場合や基板面積に対する成膜面積の割合（被覆率）が大きな場合でも、膜厚全体を均一に金属成膜することのできる金属被膜の成膜方法を提供する。【解決手段】陽極１と陰極２の間に固体電解質膜５を配し、陽極１と固体電解質膜５の間に金属イオンを含む水溶液Ｌを配し、陽極１と陰極２の間に電圧を印加し、水溶液Ｌを加圧して水溶液Ｌの液圧による加圧力Ｐを固体電解質膜５に付与し、金属イオンの金属からなる金属被膜Ｃを基板６の表面に成膜する成膜方法において、加圧力Ｐの平均圧力Yの上限値と下限値を、被覆率Xを用いた以下の式で規定される上限値と下限値の間に設定するものであり、上限値：Yup＝2.5以下、下限値：被覆率Xが0%より大きく67%以下の場合は、Yud＝(2.5×10-8)X5−(4×10-6)X4＋0.0002X3−0.0065X2＋0.079X＋1.8、被覆率Xが67%より大きく100%以下の場合は、Yud＝0.5である。【選択図】図２