The present invention provides a treatment liquid for treating a semiconductor wafer in a semiconductor formation process, the treatment liquid including: (A) hypochlorite ion; (B) a pH buffer; and (C) a tetraalkylammonium ion represented by the following formula (1):

##STR00001##

(wherein each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is independently an alkyl group having carbon number from 1 to 20).

Provided is a treatment liquid for a semiconductor wafer or the like used in a process for forming a semiconductor. Namely a treatment liquid containing (A) a hypochlorite ion, and (B) an alkylammonium salt expressed by the following Formula (1), or the like is provided.

##STR00001##

(In the Formula, “a” is an integer from 6 to 20; R.sup.1, R.sup.2, and R.sup.3 are independently, for example, an alkyl group with a carbon number from 1 to 20; and X.sup.− is, for example, a chloride ion.)

Compositions and methods are presented that selectively dissolve calcium from a variety of cementitious materials without dissolving or otherwise degrading calcium silica hydrate (CSH). Preferably, contemplated compositions comprise guanidine bisulfate hydrochloride, which can be prepared from a reaction of urea, hydrochloric acid, and sulfamic acid. Therefore, it is especially contemplated that the compositions contemplated herein are particularly suitable to clean or otherwise condition surfaces of cured concrete, Portland cement-based material, or an aggregate containing CSH.

Compositions and methods are presented that selectively dissolve calcium from a variety of cementitious materials without dissolving or otherwise degrading calcium silica hydrate (CSH). Preferably, contemplated compositions comprise guanidine bisulfate hydrochloride, which can be prepared from a reaction of urea, hydrochloric acid, and sulfamic acid. Therefore, it is especially contemplated that the compositions contemplated herein are particularly suitable to clean or otherwise condition surfaces of cured concrete, Portland cement-based material, or an aggregate containing CSH.

A cleaning method for a by-product including a refractory material or a metal compound includes a reforming process and an etching process. In the reforming process, a surface of the by-product is reformed using nitrogen-containing gas and hydrogen-containing gas. In the etching process, the reformed surface is etched using halogen-containing gas and inert gas.

A cleaning method for a by-product including a refractory material or a metal compound includes a reforming process and an etching process. In the reforming process, a surface of the by-product is reformed using nitrogen-containing gas and hydrogen-containing gas. In the etching process, the reformed surface is etched using halogen-containing gas and inert gas.

Methods, systems and apparatuses are disclosed for treating aluminum desmutting solutions by reacting, mixing and filtering an aluminum desmutting solution flow from an aluminum desmutting solution tank and controlling the amount of copper ions in an aluminum desmutting solution tank by directing a portion of the desmutting solution from a desmutting solution tank to a treatment line, reacting a portion of the desmutting solution in the treatment line and recirculating a filtered aluminum desmutting solution to the aluminum desmutting solution tank during active desmutting operation of the aluminum desmutting solution tank.

Methods, systems and apparatuses are disclosed for treating aluminum desmutting solutions by reacting, mixing and filtering an aluminum desmutting solution flow from an aluminum desmutting solution tank and controlling the amount of copper ions in an aluminum desmutting solution tank by directing a portion of the desmutting solution from a desmutting solution tank to a treatment line, reacting a portion of the desmutting solution in the treatment line and recirculating a filtered aluminum desmutting solution to the aluminum desmutting solution tank during active desmutting operation of the aluminum desmutting solution tank.

Compositions and methods are presented that selectively dissolve calcium from a variety of cementitious materials without dissolving or otherwise degrading calcium silica hydrate (CSH). Preferably, contemplated compositions comprise guanidine bisulfate hydrochloride, which can be prepared from a reaction of urea, hydrochloric acid, and sulfamic acid. Therefore, it is especially contemplated that the compositions contemplated herein are particularly suitable to clean or otherwise condition surfaces of cured concrete, Portland cement-based material, or an aggregate containing CSH.

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).