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Post-dry etching cleaning liquid composition and process for fabricating semiconductor device

Post-dry etching cleaning liquid composition and process for fabricating semiconductor device description/claims

This application is a Divisional Application of co-pending U.S. Utility application Ser. No. 11/145,731 filed on Jun. 6, 2005.

The present invention relates to a post-dry etching cleaning liquid composition that is used in cleaning for removing a residue after dry etching, and a process for fabricating a semiconductor device using the post-dry etching cleaning liquid composition.

In recent years, accompanying the finer structure of devices due to microfabrication and the increased performance of semiconductor circuit elements, new wiring materials and interlayer insulating film materials have been employed. For example, copper and an alloy having copper as a main component (hereinafter, called a ‘copper alloy’) have been used as new wiring materials for the purpose of reducing wiring resistance and inter-wiring capacitance. Copper wiring is formed by, for example, a damascene process in which, after copper is embedded using sputtering or electro-plating in a trench formed as a wiring pattern in an interlayer insulating film, an unwanted copper film portion is removed using chemical mechanical polishing (CMP), etc. Similarly, with regard to the copper alloy, there are examples in which it is used for wiring by a process analogous to the damascene process.

The introduction, as a new interlayer insulating film material, of an organic film represented by an aryl ether compound, a siloxane film represented by HSQ (Hydrogen Silsesquioxane) and MSQ (Methyl Silsesquioxane), and a porous silica film, which are low dielectric constant (low-k) materials, is also being investigated.

It is however clear that copper, copper alloy, and various types of low dielectric constant films, which are the above-mentioned new materials, have low chemical resistance compared with aluminum, aluminum alloy, and silicon oxide film, which are conventional materials. Moreover, since the various types of low dielectric constant films, which are new materials, have a chemical composition different from the silicon oxide film, which is a conventional material, a process for fabricating a semiconductor device is carried out under conditions that are different from conventional ones.

In a process for fabricating a semiconductor device dry etching, in which an interlayer insulating film or a wiring material film formed on a substrate is subjected to patterning using a resist pattern as a mask, has conventionally been carried out.

As a posttreatment for such dry etching, after the resist pattern is ashed and removed by an ashing treatment, a resist residue, etc. partially remaining on the treated surface is usually removed by a resist residue remover liquid. The resist residue referred to here means all of a resist residue, which is an incompletely ashed substance remaining on the substrate surface after the ashing treatment, a side wall polymer remaining on an etched wall surface as a by-product (also called a side wall protecting film or a rabbit ear), and an organometallic polymer and a metal oxide remaining on the side face and the base face of a via hole.

In a process for producing a semiconductor device using a new material such as copper, a copper alloy, or various types of low dielectric constant film, there is the new problem that the conventional resist residue remover liquid cannot be employed. For example, a representative conventional photoresist residue remover liquid containing an alkanolamine and a quaternary ammonium compound used for removing a resist residue formed on a substrate having aluminum, an aluminum alloy, or a silicon oxide film corrodes copper and copper alloy, which have low corrosion resistance and, furthermore, causes etching and structural change in various types of low-k film.

Hence, as a new type of photoresist residue remover liquid for removing a resist residue formed on a substrate having copper, a copper alloy, or a low-k film, the following four types have been reported.

1) A liquid containing an alkanolamine, a nitrogen-containing compound as a corrosion inhibitor, and water has been disclosed. Here, the alkanolamine is N-methylaminoethanol or monoethanolamine, and the corrosion inhibitor is uric acid, adenine, caffeine, purine, etc. (ref. JP, A, 2002-99101). 2) A liquid containing either an alkanolamine or a quaternary ammonium hydroxide, a carboxyl group-containing acidic compound, a sulfur-containing compound as a corrosion inhibitor, and water has been disclosed. Here, the alkanolamine is monoethanolamine, the quaternary ammonium hydroxide is tetramethylammonium hydroxide, the sulfur-containing corrosion inhibitor is 1-thioglycerol, and the carboxyl group-containing acidic compound is acetic acid, propionic acid, or glycolic acid (ref JP, A, 2003-76037). 3) A liquid containing an aliphatic polycarboxylic acid, a reducing material such as glyoxylic acid, and water has been disclosed by the present inventors. Here, the aliphatic polycarboxylic acid is oxalic acid, malonic acid, tartaric acid, malic acid, succinic acid, or citric acid, and the reducing material is glyoxylic acid, ascorbic acid, glucose, or mannose (ref JP, A, 2003-167360). 4) A liquid containing one type or two or more types of fluorine compound, one type or two or more types of glyoxylic acid, etc. and water has been reported by the present inventors. Here, the fluorine compound is ammonium fluoride, and the glyoxylic acid, etc. is glyoxylic acid, ascorbic acid, glucose, fructose, lactose, or mannose (ref. JP, A, 2003-280219).

On the other hand, when the interlayer insulating film is a low dielectric constant film formed from a material that is easily altered by ashing, dry etching might be carried out using an inorganic mask. In this fabrication process, after an inorganic mask layer is formed on the interlayer insulating film, a pattern is formed on the inorganic mask by a resist, dry etching, ashing, etc., and the interlayer insulating film is subjected to dry etching using the inorganic mask (ref. JP, A, 2001-44189).

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