Film forming method for metal film

A film forming method for a metal film, the film forming method comprising:

• a mounting step of mounting a substrate material on a mounting table;
• a contacting step of bringing a plating solution contained in a container into contact with the substrate material through an electrolyte membrane attached to a lower portion of the container;
• a film forming step of applying a voltage between an anode disposed on an upper side of the electrolyte membrane and the substrate material such that metal ions of the plating solution pass through the electrolyte membrane and the metal film is formed on a surface of the substrate material;
• a circulating step in which the plating solution contained in the container is circulated through a circulation path outside the container, during the film forming step, the circulation path including (i) a pump sucking the plating solution from a tank and (ii) a valve downstream of the pump, wherein the plating solution is pressure-fed into the container through the valve;
• after the metal film is formed, a sealing step of stopping the pump and subsequently closing the valve to block the circulation path and sealing the plating solution, the sealing step being performed while the plating solution contained in the container is in contact with the substrate material through the electrolyte membrane;
• and
• after the sealing step, a separating step of separating the electrolyte membrane from the substrate material by moving at least one of the mounting table and the container in a direction away from the other, after forming the metal film,
• wherein the separating step is performed with the plating solution sealed in the container.