Provided is a plating diaphragm used for a plating method including disposing the plating diaphragm between an anode and a substrate that is a cathode, applying a voltage between the anode and the substrate, in a state in which a surface of the substrate is in contact with the plating diaphragm, to reduce metal ions contained in the plating diaphragm, and depositing a metal derived from the metal ions on the surface of the substrate, to form a metal film on the surface of the substrate, the plating diaphragm containing a base made of a polyolefin porous membrane, in a case in which pure water is dropped on a surface of the plating diaphragm, a contact angle between a droplet of the pure water and the surface of the plating diaphragm after one second has passed since landing of the droplet of the pure water on the surface is from 0 to 90, and a tensile breaking strength is from 11 MPa to 300 MPa.

Provided is a metal film forming apparatus capable of forming a uniform metal film on a surface of a substrate by uniformly pressurizing an electrolyte membrane against the surface of the substrate. The film forming apparatus includes first and second film forming units, a coupling portion that couples the first and second film forming units together, a pressure device including a pressure unit that pressurizes substrates with electrolyte membranes of the respective film forming units via the coupling portion, and a power supply unit adapted to apply a voltage across each anode and each substrate. The film forming units are coupled to the coupling portion via their respective first elastic bodies that elastically deform in the pressurization direction of the pressure unit.

A bathless plating for a conductive material with composite particles or with high surface coverage. The setup for the bathless electro-plating includes a cathode, a composite mixture, a membrane, and an anode. The cathode is a conductive material. The composite mixture comprises a metal salt, an acid, and a composite material. The composite mixture is applied to the cathode. A hydrophilic membrane is applied to the composite mixture. An anode, with oxidizing properties, is applied to the membrane. A current is applied to the bathless setup. Upon removing the current and composite mixture from the cathode, a metal-based composite coating remains on the cathode.

A bathless method for plating a conductive material with composite particles or with high surface coverage. The setup for the bathless electro-plating includes a cathode, a composite mixture, a membrane, and an anode. The cathode is a conductive material. The composite mixture comprises a metal salt, an acid, and a composite material. The composite mixture is applied to the cathode. A hydrophilic membrane is applied to the composite mixture. An anode, with oxidizing properties, is applied to the membrane. A current is applied to the bathless setup. Upon removing the current and composite mixture from the cathode, a metal-based composite coating remains on the cathode.

Provided is a film forming apparatus for forming a metal film, capable of uniformly pressurizing a substrate surface with an electrolyte membrane subjected to the fluid pressure of an electrolytic solution containing metal ions during film formation even when an insoluble anode is used. A housing of the apparatus includes a partition member between the anode and the electrolyte membrane, for partitioning a housing chamber into first and second housing chambers. The partition member includes a porous body impregnated with cation exchange resin. The first housing chamber houses the anode insoluble in a first electrolytic solution. The second housing chamber has formed therein a hermetically sealed space in which a second electrolytic solution containing metal ions is enclosed within the housing, by the electrolyte membrane and the partition member. The apparatus is also provided with a pump (pressure unit) that pressurizes the second electrolytic solution in the second housing chamber.

In a film forming method, in a state where a metal solution is sealed in a first accommodation chamber of a housing with a solid electrolyte membrane and a fluid is sealed in a second accommodation chamber of a placing table with a thin film, a substrate is placed on the placing table and the placing table and the housing are moved relative to each other to cause the substrate to be interposed between the solid electrolyte membrane and the thin film, the solid electrolyte membrane and the thin film are pressed against the substrate interposed therebetween to cause the solid electrolyte membrane and the thin film to conform to a surface and a rear surface of the substrate, thereby forming a metal film.

In a film forming method, in a state where a metal solution is sealed in a first accommodation chamber of a housing with a solid electrolyte membrane and a fluid is sealed in a second accommodation chamber of a placing table with a thin film, a substrate is placed on the placing table and the placing table and the housing are moved relative to each other to cause the substrate to be interposed between the solid electrolyte membrane and the thin film, the solid electrolyte membrane and the thin film are pressed against the substrate interposed therebetween to cause the solid electrolyte membrane and the thin film to conform to a surface and a rear surface of the substrate, thereby forming a metal film.

A film forming device that avoids a leakage of a liquid electrolyte and a method for forming a metal film using the film forming device are provided. The film forming device to form the metal film includes an anode, a cathode, a solid electrolyte membrane disposed between the anode and the cathode, a solution container that defines a solution containing space between the anode and the solid electrolyte membrane, and a power supply that applies a voltage between the anode and the cathode. The solid electrolyte membrane includes a first surface exposed to the solution containing space and a second surface opposed to the cathode, and is dividable along a division surface having no common point with the first surface or the second surface.

A tin solution applicable to tin film formation by solid electrolyte deposition, and a method for forming a tin film using the solution are provided. The tin solution contains tin methanesulfonate, methanesulfonic acid, water, an isopropyl alcohol, and a polyethylene-block-poly (ethylene glycol).

Techniques for electrodepositing selenium (Se)-containing films are provided. In one aspect, a method of preparing a Se electroplating solution is provided. The method includes the following steps. The solution is formed from a mixture of selenium oxide; an acid selected from the group consisting of alkane sulfonic acid, alkene sulfonic acid, aryl sulfonic acid, heterocyclic sulfonic acid, aromatic sulfonic acid and perchloric acid; and a solvent. A pH of the solution is then adjusted to from about 2.0 to about 3.0. The pH of the solution can be adjusted to from about 2.0 to about 3.0 by adding a base (e.g., sodium hydroxide) to the solution. A Se electroplating solution, an electroplating method and a method for fabricating a photovoltaic device are also provided.