JP2010087258A - Cleaning agent for semiconductor substrate surface, method of cleaning semiconductor device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning agent for use in a cleaning step after a planarization polishing step in the step of manufacturing a semiconductor device which can remove organic substance pollution and particle pollution in short time on the surface of the semiconductor device, especially on the surface of the semiconductor device on which copper wiring is laid without causing the corrosion of the copper wiring and which can excellently clean the surface of a substrate, and a cleaning method using the same. <P>SOLUTION: A cleaning agent is used after a chemical-mechanical polishing step in the step of manufacturing a semiconductor device on the surface of which copper wiring is laid. The cleaning agent for the surface of a semiconductor substrate contains a specific triazole compound or a specific tetrazole compound as a corrosion inhibitor compound. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cleaning agent used for cleaning a semiconductor device after a planarization step by chemical mechanical polishing (hereinafter referred to as “CMP”) in a manufacturing process of a semiconductor device, and a semiconductor device using the same. This relates to the cleaning method.

In the manufacturing process of semiconductor devices such as microprocessors, memories, and CCDs, and flat panel display devices such as TFT liquid crystals, patterns with fine dimensions of about 10 to 100 nm are formed on the surface of substrates such as silicon, silicon oxide (SiO ₂ ), and glass. Formation of thin films and thin film formation are being performed, and it is an extremely important issue to reduce a small amount of contamination on the surface of the substrate in each manufacturing process.

  Among contaminations on the substrate surface, particle contamination, organic contamination, and metal contamination reduce the electrical characteristics and yield of the device, so it is necessary to reduce them as much as possible before bringing them into the next process. In order to remove such contamination, the substrate surface is generally cleaned with a cleaning liquid. However, if a highly reactive compound is used by pursuing high cleaning performance, corrosion of the copper wiring occurs, which poses a major problem for device reliability. Therefore, it is required to clean a highly clean surface with no side effects, in a short time with good reproducibility, and at low cost. This required level is becoming increasingly severe with the recent high integration and low price of devices.

  In the manufacture of a semiconductor device typified by a semiconductor integrated circuit (hereinafter referred to as LSI), a multilayer stacked structure in which layers such as insulating films and metal films are stacked on a substrate is formed. In recent years, a new metal material (Cu, etc.) having a low resistance value is used as a wiring and a low dielectric constant (Low-k) material is used as an interlayer insulating film in order to increase the speed and integration of devices, and the relative dielectric constant is 3 Interlayer insulation including low dielectric constant interlayer film of about 5 to 2.0 (for example, organic polymer type, methyl group-containing silica type, H-Si containing silica type, SiOF type, porous silica type, porous organic type, etc.) After depositing a film (ILD film) or a metal film such as copper used for wiring, the process of flattening the resulting irregularities by CMP and stacking new wiring on the flattened surface is generally performed. Is called.

  Conventionally, RCA cleaning in which an acidic or alkaline solution and hydrogen peroxide are mixed has been used for cleaning between processes. According to these cleaning agents, not only the copper oxide as a passivation to be removed adhered on the insulating film but also the metal copper of the wiring is dissolved, which may cause corrosion and disconnection of the wiring. . In addition, since many of the low dielectric constant insulating films have a hydrophobic surface, the cleaning liquid is repelled and the cleanliness is deteriorated. Further, in the cleaning after the CMP process, there is a problem that the slurry (abrasive particles) used in the CMP remains on the surface of the wiring and the low dielectric constant insulating film and is contaminated.

  In order to remove particles adhering to and remaining on the surface of the semiconductor device after the polishing process, an alkaline cleaning agent in which the semiconductor surface and the particles are electrostatically repelled is generally effective. A cleaning agent containing an agent and an alkali or organic acid has been proposed (see, for example, Patent Document 1). However, these cleaning agents are expected to be further improved from the viewpoint of efficiently removing the metal and substrate material resulting from the object to be polished and the organic residue and abrasive particles adhering to the substrate surface. It was rare.

  Further, from the viewpoint of efficiently removing organic residues and abrasive fine particles, an acidic cleaning liquid containing a specific organic acid and a surfactant has been proposed (for example, see Patent Document 2). However, with these cleaning solutions, it is possible to effectively remove impurities on the surface while suppressing corrosion and oxidation of copper wiring on the surface of a semiconductor device with a hydrophobic low dielectric constant insulating film or copper wiring. Further improvements were desired.

  From the above viewpoint, a cleaning agent that reduces corrosion of copper wiring by adding a material having an anticorrosive effect such as benzotriazole has also been proposed (see, for example, Patent Document 3), but removal of impurities such as residues, Or it is not so preferable from the viewpoint of the influence of the protective film remaining on the copper surface.

Therefore, there is a demand for a cleaning agent that can effectively remove impurities on the surface of a hydrophobic low dielectric constant insulating film or a semiconductor device coated with copper wiring while suppressing corrosion and oxidation of the copper wiring. Is the current situation.
JP 2003-289060 A Japanese Patent Laid-Open No. 10-72594 JP 2005-307187 A

  An object of the present invention made in consideration of the above problems is a cleaning agent used in a cleaning process after a planarization polishing process in a semiconductor device manufacturing process, in which a copper wiring is applied to the surface of a semiconductor device, in particular, the surface. Provided a cleaning agent and cleaning method using the same, which can remove organic contamination and particle contamination in a short time without causing copper wiring corrosion on the surface of the semiconductor device. There is to do.

As a result of intensive studies on the problems relating to the cleaning agent used after the CMP process, the present inventor improves the corrosion inhibition performance without degrading the organic residue removal performance when a compound having an NH group in the molecule is used. As a result, the present inventors have found that the above problem can be solved by using a corrosion inhibitor compound having no NH group in the molecule as a cleaning agent component, thereby completing the present invention.
That is, the present invention is as follows.

（式中R₁,R₃,R₄およびR₅は、窒素原子上の置換基（水素原子以外）を表し、R₂は水素原子もしくは炭素原子上の置換基を示す。また、R₁,R₃,R₄またはR₅と、R₂は互いに結合して連結鎖を表してもよい。）
＜２＞前記一般式（Ｉ）〜（IV）中のR₁,R₃,R₄およびR₅が、水酸基またはカルボキシル基を含む置換基である、上記＜１＞に記載の半導体表面用洗浄剤。
＜３＞前記一般式（Ｉ）〜（IV）中のR₂が、水酸基またはカルボキシル基を含む置換基である、上記＜１＞〜＜２＞に記載の半導体表面用洗浄剤。
＜４＞ｐＨが５以下である上記＜１＞〜＜３＞のいずれかに記載の半導体表面用洗浄剤。
＜５＞少なくとも１種のポリカルボン酸を含有する上記＜１＞〜＜４＞のいずれかに記載の半導体表面用洗浄剤。
＜６＞前記ポリカルボン酸が、蓚酸、クエン酸、マロン酸、マレイン酸、および酒石酸の群から選ばれる少なくとも１種である＜５＞に記載の半導体表面用洗浄剤。
＜７＞少なくとも１種の界面活性剤を含有する上記＜１＞〜＜６＞のいずれかに記載の半導体表面用洗浄剤。
＜８＞前記界面活性剤が、アニオン性界面活性剤、ノニオン性界面活性剤、およびアニオン性界面活性剤ならびにノニオン性界面活性剤の組合せの群から選ばれる少なくとも１種である上記＜７＞に記載の半導体表面用洗浄剤。
＜９＞半導体デバイスに形成された銅配線を、砥粒および酸化剤を含有する金属用研磨液を用いて化学的機械的研磨する工程と、該半導体デバイスの表面を、上記＜１＞〜＜８＞のいずれかに記載の半導体表面用洗浄剤で洗浄する工程と、を順次有する半導体デバイスの洗浄方法。 <1> A cleaning agent used after a chemical mechanical polishing step in a manufacturing process of a semiconductor device having a copper wiring on the surface, selected from compounds represented by the following general formulas (I) to (IV) A semiconductor substrate surface cleaning agent containing a corrosion inhibitor compound.

(Wherein R ₁ , R ₃ , R ₄ and R ₅ represent a substituent on the nitrogen atom (other than a hydrogen atom), R ₂ represents a hydrogen atom or a substituent on a carbon atom, and R ₁ , R ₃ , R ₄ or R ₅ and R ₂ may be bonded to each other to represent a linking chain.)
<2> The semiconductor surface cleaning according to <1>, wherein R ₁ , R ₃ , R ₄ and R _{5 in the} general formulas (I) to (IV) are a substituent containing a hydroxyl group or a carboxyl group. Agent.
<3> The semiconductor surface cleaning agent according to <1> to <2>, wherein R ₂ in the general formulas (I) to (IV) is a substituent containing a hydroxyl group or a carboxyl group.
<4> The semiconductor surface cleaning agent according to any one of <1> to <3>, wherein the pH is 5 or less.
<5> The semiconductor surface cleaning agent according to any one of <1> to <4>, which contains at least one polycarboxylic acid.
<6> The semiconductor surface cleaner according to <5>, wherein the polycarboxylic acid is at least one selected from the group consisting of oxalic acid, citric acid, malonic acid, maleic acid, and tartaric acid.
<7> The semiconductor surface cleaning agent according to any one of the above <1> to <6>, which contains at least one surfactant.
<8> In the above <7>, the surfactant is at least one selected from the group consisting of an anionic surfactant, a nonionic surfactant, and a combination of an anionic surfactant and a nonionic surfactant. The cleaning agent for semiconductor surfaces as described.
<9> A step of chemically and mechanically polishing the copper wiring formed in the semiconductor device using a metal polishing liquid containing abrasive grains and an oxidizing agent, and the surface of the semiconductor device in the above <1> to <8> a step of cleaning with the semiconductor surface cleaning agent according to any one of 8).

A semiconductor device that is an object to be cleaned to which the cleaning agent of the present invention is applied is a substrate that has been subjected to a chemical mechanical polishing process in a semiconductor device manufacturing process. Either a layer substrate or a multilayer wiring substrate in which wiring is formed on the surface thereof via an interlayer insulating film or the like may be used.
The present invention is particularly useful for cleaning a semiconductor device substrate having a metal wiring, a low dielectric constant (Low-k) insulating film, or the like on a part of or the entire surface.

When a cleaning liquid containing a protective film forming agent is used as an additive to the cleaning liquid used after CMP, the hydrophobic low dielectric constant insulating film and the surface of the semiconductor device on which the copper wiring is applied are suppressed from corrosion and oxidation of the copper wiring. The effect that it can wash efficiently is expected.
However, with the recent miniaturization of wiring and the application of various types of barrier metal metals and low-k insulating films, it is expected that both the effect of reducing corrosion and the improvement of cleaning properties are achieved. In general passive film forming agents such as benzotriazole (BTA), the components remain on the surface of the copper metal wiring, and the above-described corrosion reduction effect and cleaning properties can be obtained even in the combined use of an organic acid and a surfactant. It is difficult to achieve the effect of improving both of the above.
In the present invention, instead of such a passive film-forming agent, a corrosion inhibitor compound having a specific structure characterized by having no NH group in the structure, such as general formulas (I) to (IV). By applying it, both low corrosion and high cleaning can be achieved.

  According to the present invention, it is a cleaning agent used in a cleaning process after a planarization polishing process in a semiconductor device manufacturing process, and is present on the surface of a semiconductor device, in particular, on the surface of a semiconductor device in which copper wiring is applied to the surface. Organic substance contamination and particle contamination can be removed in a short time without causing corrosion of copper wiring, and a cleaning agent capable of highly cleaning the substrate surface and a cleaning method using the same can be provided.

Hereinafter, specific embodiments of the present invention will be described.
The cleaning agent of the present invention contains a corrosion inhibitor compound represented by a specific formula having no NH group in the molecule (hereinafter referred to as a specific corrosion prevention compound), and is used in a semiconductor device manufacturing process. After the chemical mechanical polishing step, it is suitably used for cleaning semiconductor devices, particularly device surfaces having copper wiring on the surface.
Hereinafter, each component contained in the cleaning agent of the present invention will be sequentially described.

（式中R₁,R₃,R₄およびR₅は、窒素原子上の置換基（水素原子以外）を表し、R₂は水素原子もしくは炭素原子上の置換基を示す。また、R₁,R₃,R₄またはR₅と、R₂は互いに結合して連結鎖を表してもよい。） <Specific corrosion prevention compound>
The cleaning agent of the present invention contains a specific corrosion inhibitor compound. The specific corrosion inhibiting compound is selected from compounds represented by the following general formulas (I) to (IV).

(Wherein R ₁ , R ₃ , R ₄ and R ₅ represent a substituent on the nitrogen atom (other than a hydrogen atom), R ₂ represents a hydrogen atom or a substituent on a carbon atom, and R ₁ , R ₃ , R ₄ or R ₅ and R ₂ may be bonded to each other to represent a linking chain.)

一般式（II）〜(IV)についても同様に位置異性体を含む。 It should be understood by those skilled in the art that the compound represented by the general formula (I) includes the following positional isomers.

General formulas (II) to (IV) also include regioisomers.

Examples of the substituent on the nitrogen atom represented by R ₁ , R ₃ , R ₄ and R ₅ include a linear or branched alkyl group having 1 to 9 carbon atoms, a carboxyl group, a hydroxyl group, and a carboxy group having 1 to 3 carbon atoms. A linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched alkyl group having 1 to 12 carbon atoms terminated with 1 to 3 hydroxyl groups, an alkenyl group having 2 to 12 carbon atoms, and- X—N (R ₆ ) ₂ (X is a single bond or a linear or branched alkylene group or alkenylene group having 1 to 6 carbon atoms; R ₆ may be the same or different; a hydrogen atom; A linear or branched alkyl group, a carboxyl group, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms terminated with 1 to 3 carboxy groups, and a carbon number of 1 having 1 to 3 hydroxyl groups terminated. -12 linear or branched alkyl groups) That.

As the substituent on the nitrogen atom represented by R ₁ , R ₃ , R ₄ and R ₅ , a linear or branched alkyl group having 1 to 5 carbon atoms (more preferably 1 to 3 carbon atoms), a carboxyl group, A hydroxyl group, a linear or branched alkyl group having 1 to 5 carbon atoms (more preferably 1 to 3 carbon atoms) terminated with 1 to 3 carboxy groups, and 1 to 5 carbon atoms terminated with 1 to 3 hydroxyl groups A linear or branched alkyl group (more preferably having 1 to 3 carbon atoms), an alkenyl group having 2 to 6 carbon atoms, and —X—N (R ₆ ) ₂ (X is a single bond or 1 to 5 carbon atoms). A linear or branched alkylene group or alkenylene group (more preferably having 1 to 3 carbon atoms), R ₆ may be the same or different, and may be a hydrogen atom, 1 to 5 carbon atoms (more preferably 1 to 3 carbon atoms). ) Linear or branched alkyl group, carboxyl group, hydroxyl group, A linear or branched alkyl group having 1 to 5 carbon atoms (more preferably 1 to 3 carbon atoms) terminated with a carboxy group of 3 to 3 carbon atoms, and 1 to 5 carbon atoms (more preferably 1 to 3 hydroxyl groups terminated). Is a linear or branched alkyl group having 1 to 3 carbon atoms).

Preferably methyl group, ethyl group, carboxymethyl group, carboxyethyl group, hydroxymethyl group, hydroxyethyl group, 1,2-dicarboxyethyl group, isopropyl group, 2,3-dihydroxypropyl group, (N-hydroxyethyl) An aminomethyl group, an (N-carboxyethyl) aminomethyl group, an N, N-bis (hydroxyethyl) aminomethyl group, an N, N-bis (carboxyethyl) aminomethyl group, a carboxy group, and a hydroxy group.
More preferably, methyl group, carboxymethyl group, carboxyethyl group, hydroxymethyl group, hydroxyethyl group, 1,2-dicarboxyethyl group, 2,3-dihydroxypropyl group, N, N-bis (hydroxyethyl) aminomethyl A group, a carboxy group, and a hydroxy group.
The substituent represented by R ₁ , R ₃ , R ₄ and R ₅ is a substituent containing a hydroxyl group or a carboxyl group, which contributes to improving the chelating effect on Cu to prevent corrosion and has high water solubility. From the viewpoint of hardly forming a residue.

Examples of the substituent on the carbon atom represented by R ₂ include a linear or branched alkyl group having 1 to 9 carbon atoms, a carboxyl group, a hydroxyl group, and a linear chain having 1 to 12 carbon atoms having 1 to 3 carboxy groups at its ends. Alternatively, a branched alkyl group, a linear or branched alkyl group having 1 to 12 carbon atoms terminated with 1 to 3 hydroxyl groups, and an alkenyl group having 2 to 9 carbon atoms may be mentioned.
The substituent on the carbon atom represented by R ₂ is more preferably a linear or branched alkyl group having 1 to 5 carbon atoms (more preferably 1 to 3 carbon atoms), a carboxyl group, a hydroxyl group, or a carboxy group having 1 to 3 carbon atoms. A linear or branched alkyl group having 1 to 5 carbon atoms (more preferably 1 to 3 carbon atoms) having a terminal group, and 1 to 5 carbon atoms having 1 to 3 hydroxyl groups (more preferably 1 carbon atom). -3) linear or branched alkyl groups and alkenyl groups having 2 to 6 carbon atoms (more preferably 2 to 4 carbon atoms).
Preferably methyl group, ethyl group, propyl group, pentyl group, carboxymethyl group, carboxyethyl group, hydroxymethyl group, hydroxyethyl group, isopropyl group, 2,3-dihydroxypropyl group, more preferably methyl group, ethyl group , Carboxyl group, carboxymethyl group, carboxyethyl group, hydroxymethyl group, hydroxyethyl group, isopropyl group, and 2,3-dihydroxypropyl group.
As a connecting chain formed by combining R ₁ , R ₃ , R ₄ or R ₅ and R ₂ , — (CH ₂ ) n— (n = 1 to 8) (the methylene chain has 1 to 5 may be substituted with an alkyl group, a carboxyl group or a hydroxyl group).

  Examples of the specific corrosion inhibiting compound include the following compounds, but the present invention is not limited thereto. The compounds represented by the following structures include those positional isomers.

  Among the above specific examples, 1-methyltetrazole, 1-ethyltetrazole, 1-hydroxymethylbenzotriazole, 1-methyltetrazole, 1-ethyltetrazole, 1-methyltetrazole, 1-methyltetrazole, Hydroxymethyltetrazole, 1-hydroxyethyltetrazole, 1-methylbenzotriazole, 1-ethylbenzotriazole, 1-hydroxyethylbenzotriazole, 1-carboxymethylbenzotriazole, 1-carboxyethylbenzotriazole, 5-methyl-1-hydroxy Methylbenzotriazole, 5-methyl-1-hydroxyethylbenzotriazole, 5-methyl-1-carboxymethylbenzotriazole, 5-methyl-1-carboxyethylbenzotriazole, 1,5-pe Tamethylenetetrazole, 1- (2,3-dihydroxypropyl) benzotriazole, 5-methyl-1- (1,2-dicarboxyethyl) -benzotriazole, 5-methyl-1- (2,3-dihydroxypropyl) -Benzotriazole, 1- (1,2-dicarboxyethyl) benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 5-hydroxymethyl-1- [N, N-bis ( Hydroxyethyl) aminomethyl] benzotriazole, 5-carboxy-1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 5-carboxy-1-methyltetrazole are preferred. Further, among these, compounds having a substituent containing a hydroxyl group or a carboxyl group are more preferred from the viewpoint of contributing to the improvement of the chelating effect on Cu for preventing corrosion and being difficult to form a residue due to high water solubility.

The content of the specific corrosion-inhibiting compound of the present invention is 0.000001% by mass to 5% by mass, preferably 0.00001% by mass to 4% by mass, based on the total mass of the semiconductor surface cleaning agent. More preferably, it is 0.0001 mass%-3 mass%, More preferably, it is 0.001 mass%-2 mass%.
By setting it as the said range, without causing corrosion of copper wiring, organic matter contamination and particle contamination can be removed in a short time, and the substrate surface can be highly purified.
In the cleaning agent of the present invention, the specific corrosion inhibiting compound may be used alone or in combination of two or more.

<Polycarboxylic acid>
The cleaning agent of the present invention preferably contains a polycarboxylic acid from the viewpoint of removing metal impurities and metal complexes.
The polycarboxylic acid in the present invention may be any compound and salt thereof containing at least two carboxyl groups in the molecule, but preferably contains 2 to 8 carboxyl groups in the molecule. It is a compound or salt, more preferably a compound or salt containing 2 to 6 carboxyl groups in the molecule, and still more preferably a compound or salt containing 2 to 4 carboxyl groups in the molecule.

Examples of the polycarboxylic acid that can be used in the present invention include dicarboxylic acids such as succinic acid, malonic acid, maleic acid, and succinic acid; oxypolycarboxylic acids such as tartaric acid, malic acid, and citric acid: and salts thereof. It is done.
Among the above polycarboxylic acids, oxalic acid, citric acid, malonic acid, lactic acid, maleic acid, malic acid, and tartaric acid are preferred from the viewpoint of material safety, cost, and cleaning performance, and oxalic acid, citric acid, maleic acid Moreover, malic acid and tartaric acid are more preferable.

  The content of the polycarboxylic acid in the cleaning agent of the present invention is preferably 0.005 to 30% by mass with respect to the total mass of the cleaning agent, from the viewpoint of achieving both cleaning efficiency and a reduction in the influence on the copper wiring. Particularly preferably, the content is 0.01 to 10% by mass.

  In the cleaning agent of the present invention, the polycarboxylic acid may be used alone or in combination of two or more at any ratio.

Moreover, the cleaning agent of the present invention can contain organic acids other than polycarboxylic acids. Other organic acids are organic compounds other than polycarboxylic acids that show acidity (pH <7) in water, and have acidic functional groups such as carboxyl groups, sulfo groups, phenolic hydroxyl groups, and mercapto groups. An organic compound is mentioned.
The content when other organic acids are used is preferably equal to or less than the polycarboxylic acid.

<Surfactant>
It is preferable that the cleaning agent of the present invention contains a surfactant in terms of improving wettability to the substrate and improving the cleaning property associated therewith.
Examples of the surfactant that can be used in the present invention include an anionic surfactant, a nonionic surfactant, and a surfactant made of a combination thereof. When a cationic surfactant is added, the cation moiety and the organic acid used together interact to reduce the function / effect of the organic acid. For this reason, it is preferable to use the surfactant which consists of anionic surfactant, nonionic surfactant, or those combination.
Each surfactant will be described below.

<Anionic surfactant>
Examples of the anionic surfactant include carboxylate, sulfonate, sulfate ester salt, and phosphate ester salt.
As carboxylates, soaps, N-acyl amino acid salts, polyoxyethylene or polyoxypropylene alkyl ether carboxylates, acylated peptides;
As sulfonates, alkyl sulfonates, sulfosuccinates, α-olefin sulfonates, N-acyl sulfonates;
As sulfate salts, sulfated oils, alkyl sulfates, alkyl ether sulfates, polyoxyethylene or polyoxypropylene alkyl allyl ether sulfates, alkyl amide sulfates;
Examples of phosphoric acid ester salts include alkyl phosphates, polyoxyethylene or polyoxypropylene alkyl allyl ether phosphates.

  In addition, preferable anionic surfactants in the present invention include those having at least one aromatic ring structure in the molecule, and examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a tetracene ring, and a phenanthrene. Ring, chrysene ring, pyrene ring and the like.

  Examples of the anionic surfactant that can be suitably used in the present invention include, for example, alkylbenzene sulfonic acid and its salt, alkyl naphthalene sulfonic acid and its salt, alkyl diphenyl ether sulfonic acid and its salt, alkyl diphenyl ether disulfonic acid and its salt, Examples thereof include phenolsulfonic acid formalin condensate and salt thereof, or arylphenolsulfonic acid formalin condensate and salt thereof.

  In the anionic surfactants listed above, the alkyl group that can be introduced into the aromatic ring may be either linear or branched, and has 2 to 30 carbon atoms (preferably 3 to 3 carbon atoms). 22) is preferred, and examples thereof include propyl, butyl, pentyl, hexyl, octyl, nonyl, decyl, dodecyl, hexadecyl, octadecyl and the like.

  Moreover, when these anionic surfactants take a salt structure, examples of the salt structure include sodium salt, potassium salt, ammonium salt, triethanolamine salt, tetramethylammonium salt and the like.

  More specific examples of the anionic surfactant include, for example, dodecylbenzenesulfonic acid, dodecyldiphenyletherdisulfonic acid, diphenyletherdisulfonic acid, propylnaphthalenesulfonic acid, triisopropylnaphthalenesulfonic acid, ammonium dodecylbenzenesulfonate, dodecyldiphenylethersulfone. An ammonium acid is mentioned.

  Other examples of the anionic surfactant that can be used in the present invention include, in addition to the aromatic ring structure in the molecule, for example, polyoxyethylene group, polyoxypropylene group, fluoroalkyl group, acetylene group, hydroxyl group and the like. Surfactant which further has a substituent is mentioned. More specific examples include polyoxyethylene tristyryl phenyl ether phosphate, phenolsulfonic acid formalin condensate, and the like.

  Among the above-described anionic surfactants, dodecylbenzenesulfonic acid, dodecyldiphenyl ether disulfonic acid, polyoxyethylene lauryl ether, and polyoxyethylene tristyryl phenyl ether phosphate are more preferable.

  Commercially available products may be used as the anionic surfactant. For example, Perex NBL (sodium alkylnaphthalenesulfonate, manufactured by Kao Corporation), Neoperex GS (Dodecylbenzenesulfonic acid, manufactured by Kao Corporation), Neo Perex GS-15 (sodium dodecylbenzenesulfonate, manufactured by Kao Corporation), Perex SS-L (sodium alkyldiphenyl ether disulfonate, manufactured by Kao Corporation), demole NL (sodium salt of β-naphthalenesulfonic acid formalin condensate) , Manufactured by Kao Corporation) and the like can be suitably used.

  One of these anionic surfactants may be used alone for the cleaning agent of the present invention, or two or more thereof may be used in combination at any ratio.

《Nonionic surfactant》
Nonionic surfactants include ether type, ether ester type, ester type, and nitrogen-containing type. As ether type, polyoxyethylene alkyl and alkylphenyl ether, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene Examples include polyoxypropylene block polymers and polyoxyethylene polyoxypropylene alkyl ethers.

Examples of the ether ester type include polyoxyethylene ether of glycerin ester, polyoxyethylene ether of sorbitan ester, and polyoxyethylene ether of sorbitol ester.
Examples of the ester type include polyethylene glycol fatty acid ester, glycerin ester, polyglycerin ester, sorbitan ester, propylene glycol ester, and sucrose ester.
Examples of the nitrogen-containing type include fatty acid alkanolamides, polyoxyethylene fatty acid amides, and polyoxyethylene alkylamides.
In addition, fluorine surfactants, silicone surfactants, and the like can be given.

  One of these nonionic surfactants may be used alone in the cleaning agent of the present invention, or two or more thereof may be used in combination at any ratio.

  In the case of containing a plurality of kinds of surfactants, two or more kinds of anionic surfactants may be used, or an anionic surfactant and a nonionic surfactant may be used in combination.

  The total content of the surfactant in the cleaning agent of the present invention is preferably 0.001 g to 10 g, more preferably 0.01 g to 1 g, and more preferably 0.02 g to 0 g in 1 L of the cleaning agent. More preferably, it is .5 g.

<Chelating agent>
The cleaning agent of the present invention may contain a chelating agent.
As a chelating agent, a general-purpose hard water softening agent that is a precipitation inhibitor of calcium or magnesium or an analogous compound thereof can be used, and two or more of these may be used in combination as necessary. The addition amount of the chelating agent may be an amount sufficient to sequester metal ions such as mixed polyvalent metal ions, and is generally about 5 ppm to 10,000 ppm in the cleaning agent.

  Examples of the chelating agent include aminocarboxylic acids or aminocarboxylic acid salts, polyaminocarboxylic acids or polyaminocarboxylic acid salts, monoaminopolycarboxylic acids or monoaminopolycarboxylic acid salts.

  Aminocarboxylic acids include glycine, L-alanine, β-alanine, L-2-aminobutyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-isoleucine, L-alloisoleucine, L-phenylalanine , L-proline, sarcosine, L-ornithine, L-lysine, taurine, L-serine, L-threonine, L-allothreonine, L-homoserine, L-tyrosine, 3,5-diiodo-L-tyrosine, β- (3,4-dihydroxyphenyl) -L-alanine, L-thyroxine, 4-hydroxy-L-proline, L-cysteine, L-methionine, L-ethionine, L-lanthionine, L-cystathionine, L-cystine, L -Cystic acid, L-aspartic acid, L-glutamic acid, etc. are mentioned.

Examples of polyaminocarboxylic acids include diethylenetriaminepentaacetic acid (DTPA) and ethylenediaminetetraacetic acid (EDTA).
Examples of monoaminopolycarboxylic acids include N-2-hydroxyethyliminodiacetic acid, L-aspartic acid-N, N-diacetic acid, and further include ammonium salts and alkali metal salts thereof. Can do.

  The cleaning agent of the present invention is an aqueous solution. That is, those obtained by dissolving the above-described essential components or other components used together as desired in an aqueous solvent are preferable. As the water used as the solvent, it is preferable to use deionized water or ultrapure water which does not contain impurities or has its content reduced as much as possible from the viewpoint of effect. From the same viewpoint, electrolytic ionic water obtained by electrolysis of water, hydrogen water in which hydrogen gas is dissolved in water, or the like can also be used.

[PH of cleaning agent]
The pH of the cleaning agent of the present invention is not particularly limited, and can be appropriately selected and adjusted in the range of about 0.5 to 12 depending on the characteristics of the device to be cleaned, the type of impurities to be removed, and the like. However, the pH is preferably 5 or less from the viewpoint of sufficiently preventing corrosion of the surface to be cleaned (the surface of the substrate for a semiconductor device) and sufficiently removing metal contamination. The pH of the cleaning liquid is more preferably 1-5, and still more preferably 1-3.5.
By adjusting the pH to the above range, adsorption of particles to the copper metal surface can be suppressed, metal contamination can be sufficiently removed, and corrosion of the copper metal surface can be further suppressed.

  The pH value can be adjusted by adding an organic acid. As the organic acid, for example, a water-soluble one is desirable, and one selected from the following group is more suitable. Formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid , N-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, Tartaric acid, citric acid, lactic acid, hydroxyethyliminodiacetic acid, iminodiacetic acid, diethylhydroxyglycine and the like can be used.

  Further, in the cleaning liquid of the present invention, a general pH adjuster can be used, but a general pH adjuster is used from the viewpoint of damage to metals and insulating films and contamination with metals in inorganic alkali. Is preferably not used. The pH adjuster here is, for example, an inorganic acid such as nitric acid or sulfuric acid for an acid, or potassium hydroxide or ammonia for an alkali.

  The cleaning agent of the present invention is suitably used for cleaning a substrate for a semiconductor device having a metal or metal compound layer on the surface or wiring formed of these. The cleaning agent of the present invention is particularly suitable for cleaning a substrate for a semiconductor device having a copper wiring on the surface because the concern of causing corrosion or oxidation to the copper wiring is low.

The semiconductor device cleaning method of the present invention will be described below.
<Washing method>
The semiconductor device cleaning method of the present invention is characterized by using the above-described cleaning agent of the present invention, and is performed subsequent to the chemical mechanical polishing step (CMP step) in semiconductor device manufacturing. is there.
More specifically, the semiconductor device cleaning method of the present invention includes a step of chemically and mechanically polishing a copper wiring formed on a semiconductor device using a metal-polishing liquid containing abrasive grains and an oxidizing agent, and the semiconductor. And sequentially cleaning the surface of the device with the semiconductor surface cleaning agent of the present invention described above.

Usually, in the CMP process, a polishing liquid is supplied to a polishing pad on a polishing surface plate and brought into contact with a surface to be polished such as a substrate for a semiconductor device, which is an object to be polished. It is a process to do. Thereafter, in the cleaning step to be performed, the semiconductor device substrate that has been polished is placed on a spinner, and the cleaning agent is supplied at a flow rate of 100 to 2000 ml / min. In general, a cleaning method is used in which the substrate is supplied to the substrate surface under the above conditions and brush scrubbed at room temperature for 10 to 60 seconds.
Cleaning can also be performed using a commercially available cleaning tank. For example, a wafer cleaning machine manufactured by MAT (trade name: ZAB8W2M) is used, and a PVA roll brush is brought into contact with a scrubbing unit built in the apparatus. It can also be performed by scrub cleaning.

As a metal used for the substrate for a semiconductor device which is an object to be polished, W or Cu is mainly mentioned. In recent years, LSIs using copper with low wiring resistance have been developed.
With the miniaturization of wiring aiming at higher density, it is necessary to improve the conductivity and electronic migration resistance of copper wiring, and high productivity can be demonstrated without contaminating these high-definition and high-purity materials. Technology is required.

As a process of cleaning a substrate having Cu on the surface and further having a low dielectric constant insulating film as an interlayer insulating film and having a copper wiring on the surface, CMP was performed particularly on the Cu film. Examples include a subsequent cleaning process, and a cleaning process after opening a hole in the interlayer insulating film on the wiring by dry etching. In these cleaning processes, impurities such as impurities and particles existing on the surface are efficiently removed. This is particularly important for maintaining the purity and accuracy of the wiring. From such a viewpoint, the cleaning agent of the present invention is preferably used in these cleaning steps. Further, as described above, since the cleaning agent of the present invention does not cause corrosion or oxidation on the copper wiring, the cleaning agent of the present invention is also preferably used from this viewpoint.
The cleaning agent of the present invention is also preferably used for the purpose of efficiently removing the passive film forming agent residue adsorbed on the copper wiring surface.

  In order to confirm the effect of removing impurities in the cleaning process, it is necessary to detect foreign matter on the wafer. In the present invention, as a device for detecting foreign matter, a defect inspection apparatus ComPLUS3 manufactured by Applied Materials technology and Applied Materials are used. A Review SEM observation device manufactured by technology, SEM vision G3, is preferably used.

  According to the cleaning method of the present invention, the impurity metal on the surface of the semiconductor device substrate that has completed the CMP process, the substrate material, the impurity inorganic material including the polishing scraps of the interlayer insulating film, and the organic material including the residue of the passive film forming agent Particles such as abrasive grains can be removed efficiently, especially for devices that require high-precision wiring, and multilayers that form a new interlayer insulating film and wiring after flattening a single-layer substrate When planarizing a wiring board or the like, it is suitable for cleaning a device that requires efficient removal of impurities in each step. Further, even when the semiconductor device substrate has copper wiring, the copper wiring is not corroded or oxidized.

  Hereinafter, the present invention will be described by way of examples. The present invention is not limited to these examples.

<Preparation of polishing liquid>
・ Colloidal silica (abrasive grains: average particle diameter 30 nm) 5 g / L
・ Benzotriazole (BTA) 1g / L
・ Glycine 10g / L
Pure water was added to make a total volume of 1000 mL, and the pH was adjusted to 6.5 using nitric acid and ammonia.
To the polishing liquid, 15% / L of 30% hydrogen peroxide (oxidant) was added immediately before polishing.

<Cu wafer polishing>
-Polishing rate evaluation-
8 inch wafer polishing The apparatus “LGP-612” manufactured by Lapmaster Co., Ltd. was used as a polishing apparatus, and the film provided on each wafer was polished under the following conditions while supplying slurry.
Base: 8 inch SEMATECH 854 Silicon wafer with copper wiring pattern Table rotation speed: 64 rpm
Head rotation speed: 65rpm
(Processing linear velocity = 1.0 m / s)
Polishing pressure: 140 hPa
Polishing pad: Rohm and Haas
Part No. IC-1400 (K-grv) + (A21)
Slurry supply rate: 200 ml / min

Example 1
<Preparation of cleaning solution>
Citric acid (organic acid): 200.0 g / L
・ 1-ethyltetrazole (specific corrosion inhibitor compound) 5.0 g / L
・ Dodecylbenzenesulfonic acid (surfactant) 5.0 g / L
The above components were mixed to prepare a cleaning liquid concentrate, which was further diluted with pure water to obtain the cleaning liquid of Example 1. The dilution ratio was a washing ratio: pure water = 1: 40 by mass ratio.

(Examples 2 to 13 and Comparative Examples 1 to 4)
In the preparation of the cleaning liquid of Example 1, an organic acid, a specific corrosion-inhibiting compound, and a surfactant were mixed in the composition shown in Table 1 below, and diluted at the dilution ratio shown in Table 1 below. Thus, cleaning liquids of Examples 2 to 13 and Comparative Examples 1 to 4 were obtained.

<Cleaning test>
The silicon substrate with a copper film polished under the above conditions was subjected to a cleaning test by cleaning using the cleaning agents of Examples 1 to 13 and Comparative Examples 1 to 4 prepared according to the above prescription.
The cleaning was performed by scrub cleaning with a PVA roll brush in contact with a scrub part built in a wafer cleaning apparatus manufactured by MAT, ZAB8W2M. The cleaning solution is allowed to flow for 25 seconds at 400 ml / min on the upper side and 400 ml / min on the lower side, and then pure water (deionized water) is allowed to flow for 650 ml / min on the upper side of the polishing substrate and for 35 seconds at 500 ml / min on the lower side. Further, the treatment was performed for 30 seconds with a spin dry device incorporated in the above device.

<Evaluation of organic residue removal and corrosion prevention performance>
Removal of organic residues remaining on the surface of the Cu wafer cleaned and dried with the cleaning agents of Examples 1 to 23 and Comparative Examples 1 to 4 and evaluation of corrosion prevention performance were performed. These surface states are confirmed by using a defect inspection apparatus ComPLUS3 manufactured by Applied Materials technology, and randomly extracting 100 defects from the detected defects, and using a Revive SEM observation apparatus, SEM vision3 manufactured by Applied Materials technology. Then, the image income was calculated, classification was performed for each defect type, the ratio of each defect type was determined, and the number of wafers for each defect type was calculated. Evaluation was made according to the following criteria, and the results are shown in Table 1 below.

-Evaluation criteria-
○ The number of organic residue or corrosion on the wafer per 1 cm ² is 0 or more and less than 0.1, and there is no practical problem. Δ: The number of organic residue or corrosion on the wafer per 1 cm ² is 0. 1 or more and less than 1 with practically no problem × 1: The number of organic residue on the wafer per 1 cm ² or corrosion is 1 or more and practically impossible

  In Table 1, the ratio of the cleaning liquid to pure water in the “dilution ratio” column is based on mass.

As is apparent from Table 1, when the cleaning is performed using the cleaning agents of Examples 1 to 23 after the CMP process, the organic residue adhered to the surface is effectively cleaned and removed without corroding the substrate. I understand that I was able to. In particular, when a triazole compound or a tetrazole compound having a hydroxyl group or a carboxyl group in the molecule is used, an excellent effect is exhibited in both cleaning and removal of organic residues and prevention of corrosion.
On the other hand, when the cleaning agents of Comparative Examples 1 and 4 that do not contain a corrosion-inhibiting compound are used, corrosion occurs compared to the case of using the cleaning agents of Examples 1 to 23, which is not practical. . Moreover, in Comparative Examples 2 and 3 using a compound having an NH group in the molecule as a corrosion inhibitor, organic residue cannot be prevented and it is not at a practical level.
Thus, it turned out that the cleaning agents of Examples 1 to 23 are excellent in cleaning properties while maintaining corrosion suppression of the copper wiring applied to the Cu wafer.

Claims (9)

Corrosion selected from compounds represented by the following general formulas (I) to (IV), which is a cleaning agent used after a chemical mechanical polishing step in a manufacturing process of a semiconductor device having copper wiring on the surface. A semiconductor substrate surface cleaning agent comprising an inhibitor compound.

(Wherein R ₁ , R ₃ , R ₄ and R ₅ represent a substituent on the nitrogen atom (other than a hydrogen atom), R ₂ represents a hydrogen atom or a substituent on a carbon atom, and R ₁ , R ₃ , R ₄ or R ₅ and R ₂ may be bonded to each other to represent a linking chain.) The semiconductor substrate surface cleaning agent according to claim 1, wherein R ₁ , R ₃ , R ₄ and R _{5 in the} general formulas (I) to (IV) are a substituent containing a hydroxyl group or a carboxyl group. The semiconductor substrate surface cleaning agent according to claim 1 or 2, wherein R ₂ in the general formulas (I) to (IV) is a substituent containing a hydroxyl group or a carboxyl group.   The cleaning agent for a semiconductor substrate surface according to any one of claims 1 to 3, wherein the pH is 5 or less.   The cleaning agent for semiconductor substrate surfaces according to any one of claims 1 to 4, comprising at least one polycarboxylic acid.   The semiconductor surface cleaning agent according to claim 5, wherein the polycarboxylic acid is at least one selected from the group consisting of oxalic acid, citric acid, malonic acid, maleic acid, and tartaric acid.   The semiconductor substrate surface cleaning agent according to any one of claims 1 to 6, comprising at least one surfactant.   The semiconductor substrate according to claim 7, wherein the surfactant is at least one selected from the group of an anionic surfactant, a nonionic surfactant, and a combination of an anionic surfactant and a nonionic surfactant. Surface cleaning agent. A step of chemically and mechanically polishing the copper wiring formed in the semiconductor device using a metal polishing liquid containing abrasive grains and an oxidizing agent;
A method for cleaning a semiconductor device, comprising: sequentially cleaning the surface of the semiconductor device with the cleaning agent for a semiconductor substrate surface according to any one of claims 1 to 8.