Provided is an etchant composition for a multilayered metal film comprising both a layer comprising copper and a layer comprising molybdenum, the etchant composition: being capable of etching en bloc a multilayered metal film comprising a layer constituted of copper or an alloy including copper as the main component and a layer constituted of molybdenum or an alloy including molybdenum as the main component; being effective in preventing the molybdenum layer from being undercut; making it easy to regulate the component concentrations so as to accommodate the cross-sectional shape control and cross-section; and being stable. Also provided are a method of etching using the etchant composition and a method for prolonging the life of the etchant composition. The etchant composition according to the present invention is an etchant composition for use in etching en bloc a multilayered metal film comprising a layer constituted of copper or an alloy including copper as the main component and a layer constituted of molybdenum or an alloy including molybdenum as the main component, and comprises hydrogen peroxide, an organic acid, an amine compound, an azole, and a hydrogen peroxide stabilizer (no inorganic acid is contained therein).

Disclosed is a method of regenerating a nitric and hydrofluoric acid bath contained in a machining vessel, the method including, when the etching bath is spent, performing steps of: transferring a portion of the spent etching bath, referred to as the spent solution, from the machining vessel into a reactor; adding NaF and NaNO.sub.3 to the spent solution, to form HF, HNO.sub.3, and Na.sub.2TiF.sub.6; separating the resulting precipitate from the supernatant; transferring the supernatant, which is a regenerated solution, into a tank; measuring the concentrations of HF, of HNO.sub.3, and of dissolved titanium in the tank and in the machining vessel; and determining the volume of regenerated solution that can be added to the spent etching bath to obtain a regenerated bath in which the concentrations of HF, of HNO.sub.3, and of dissolved titanium lie in acceptable concentration ranges, and transferring the regenerated solution into the machining vessel.

Disclosed is a method of regenerating a nitric and hydrofluoric acid bath contained in a machining vessel, the method including, when the etching bath is spent, performing steps of: transferring a portion of the spent etching bath, referred to as the spent solution, from the machining vessel into a reactor; adding NaF and NaNO.sub.3 to the spent solution, to form HF, HNO.sub.3, and Na.sub.2TiF.sub.6; separating the resulting precipitate from the supernatant; transferring the supernatant, which is a regenerated solution, into a tank; measuring the concentrations of HF, of HNO.sub.3, and of dissolved titanium in the tank and in the machining vessel; and determining the volume of regenerated solution that can be added to the spent etching bath to obtain a regenerated bath in which the concentrations of HF, of HNO.sub.3, and of dissolved titanium lie in acceptable concentration ranges, and transferring the regenerated solution into the machining vessel.

Provided is a copper etchant composition including: a first organic acid containing one or more amine groups, and one or more carboxylic acid groups; a second organic acid; an amine compound; hydrogen peroxide; and a phosphate compound, which has the increased number of processing sheets and etching uniformity, when etching copper.

Provided is a copper etchant composition including: a first organic acid containing one or more amine groups, and one or more carboxylic acid groups; a second organic acid; an amine compound; hydrogen peroxide; and a phosphate compound, which has the increased number of processing sheets and etching uniformity, when etching copper.

The current invention concerns a method for increasing an iron content of a solution by converting low iron containing solutions into highly concentrated ferric chloride solutions by adding iron containing substances. The invention concerns also methods for transporting and storage of said highly concentrated ferric chloride solutions.

A substrate processing apparatus includes: a processing tank configured to store a processing liquid for processing a substrate; a circulation path through which the processing liquid is taken out from the processing tank and is returned to the processing tank; a substrate holder configured to hold the substrate; a lifter configured to raise and lower the substrate holder between an immersion position inside the processing tank and a standby position above the processing tank; and a controller configured to control the lifter, wherein the processing liquid is a mixed liquid obtained by mixing a first component and a second component and generates a heat of mixing, and the controller is configured to perform a control to immerse the substrate in the mixed liquid before a temperature of the mixed liquid rises due to the heat of mixing and reaches a peak temperature.

A substrate processing apparatus includes: a processing tank configured to store a processing liquid for processing a substrate; a circulation path through which the processing liquid is taken out from the processing tank and is returned to the processing tank; a substrate holder configured to hold the substrate; a lifter configured to raise and lower the substrate holder between an immersion position inside the processing tank and a standby position above the processing tank; and a controller configured to control the lifter, wherein the processing liquid is a mixed liquid obtained by mixing a first component and a second component and generates a heat of mixing, and the controller is configured to perform a control to immerse the substrate in the mixed liquid before a temperature of the mixed liquid rises due to the heat of mixing and reaches a peak temperature.

A method for recovering tin and/or tin alloy from a substrate comprising providing a substrate having tin and/or tin alloy thereon; contacting the tin and/or tin alloy with a stripping solution comprising an inorganic acid and a persulfate compound; recovering tin salt and/or tin alloy salt precipitated from the stripping solution; and recovering tin and/or tin alloy from the tin salt and/or tin alloy salt, respectively.

The subject matter of the present invention is a method to extract or recover hydrochloric acid from hydrochloric acid solutions containing metal by means of pyrohydrolytic treatment, followed by absorption and/or condensation of the gaseous hydrogen chloride thus formed in order to form hydrochloric acid. According to the invention, a first partial flow of the hydrochloric acid solution containing metal undergoes pyrohydrolytic treatment and a second partial flow of the metal-containing solution is fed to the absorption column. A device for implementing the process according to the invention is also the subject of the present invention.