KR20140019464A - Polishing agent and method for polishing substrate - Google Patents

Abstract

The invention present provides a polishing agent to polish a layer which includes a carboxylic acid derivative which is selected from a group consisting of a phthalic acid compound, an isophthalic acid compound, and an alkyldicarboxylic acid compound represented by general formula (I): HOOC-R-COOH, salt thereof, and acid anhydride, a metal anticorrosive agent, water, and cobalt with pH of 4.0 or less. In general formula (I), R is an alkylene group with 4-10 carbon atoms.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a polishing apparatus,

The present invention relates to a polishing method and a polishing method for a substrate.

2. Description of the Related Art In recent years, a new microfabrication technique has been developed along with high integration and high performance of a semiconductor integrated circuit (hereinafter referred to as " LSI "). (Hereinafter referred to as " CMP ") method is a technique frequently used in planarization of an insulator, metal plug formation, buried wiring formation, etc. in an LSI manufacturing process, particularly, a multilayer wiring formation process.

In recent years, attempts have been made to use a copper alloy as a wiring material in order to improve the performance of an LSI. However, it is difficult for the copper alloy to be micro-machined by the dry etching method frequently used in the formation of the conventional aluminum alloy wiring. Thus, for example, a so-called damascene method is mainly employed in which a copper alloy thin film is deposited on an insulating film on which a trench is previously formed and buried, and a copper alloy thin film other than the trench is removed by CMP to form a buried wiring See, for example, Patent Document 1).

A general method in CMP of a metal is to attach a polishing cloth on a circular polishing platen and to immerse the surface of the polishing cloth with a liquid metal abrasive to press the surface of the substrate on which the metal film is formed, (Hereinafter abbreviated as "polishing pressure") is applied to the abrasive platen by rotating the polishing platen to remove the metal film of the convex portion by mechanical friction between the abrasive for metal and the convex portion of the metal film.

The metal abrasive used in the CMP generally contains an oxidizing agent and an abrasive grain, and further, a metal dissolving agent, a metal corrosion inhibitor and the like are added as necessary. When these are added, it is considered as a basic mechanism that the surface of the metal film is oxidized by a metal dissolving agent and the oxide layer is shaved by abrasive grains. The oxide layer on the surface of the metal film as the concave portion is not exposed to the polishing cloth much and the effect of the sharpening due to the abrasive grains is not obtained and therefore it is considered that the metal layer of the convex portion is removed with the progress of the CMP and the surface of the substrate is planarized have.

On the other hand, as shown in Fig. 1 (a), on the lower layer of the conductive material layer 5 made of a wiring metal such as copper or a copper alloy, copper diffusion prevention into the insulator 2 formed on the silicon substrate 1 Barrier metal conductor film (hereinafter referred to as " barrier metal layer 3 ") for improving adhesion is formed. Therefore, it is necessary to remove the exposed barrier metal layer 3 by CMP other than the wiring portion for embedding the wiring metal.

1 (a) to 1 (b), and the first polishing step in which the conductive material layer 5 is polished to a state shown in FIG. 1 (b) , And a " second polishing step " for polishing the barrier metal layer 3 up to a state shown in Fig. 4A and Fig. 5B), and polishing with different abrasive agents is generally applied.

However, with the miniaturization of the design rule, each layer of the wiring formation step tends to become thin. However, by thinning the barrier metal layer 3, the effect of preventing the diffusion of a conductive material containing at least one selected from, for example, copper or a copper alloy and oxides thereof is deteriorated. Further, as the wiring width is narrowed, the filling property of the conductive material is lowered, and voids called voids are generated in the wiring portion. In addition, adhesion with the conductive material layer also tends to decrease. Therefore, it has been studied to replace the metal used for the barrier metal layer 3 in Fig. 1 with a metal containing a Co (cobalt) element. 2 (a), a layer of a metal containing a cobalt element (hereinafter referred to as "cobalt layer 4") is interposed between the barrier metal layer 3 and the conductive material layer 5 It is also proposed to intervene. The diffusion of the conductive material is suppressed by using the cobalt layer 4 and cobalt has a high affinity with copper which is widely used as a conductive material, so that the filling property of the copper layer to the wiring portion is improved, The adhesion with the layer can be compensated.

When cobalt is used as the barrier metal layer, it is necessary for the metal polishing compound to remove the excess cobalt layer. Various kinds of metal abrasives are known, but on the other hand, when there is any metal abrasive, it can not be said that any metal can be removed. As a conventional metal abrasive, it is known to use a metal such as copper, tantalum, titanium, tungsten, aluminum or the like as a subject to be polished (a subject to remove an excessive portion), but an abrasive for polishing cobalt is not known .

However, since cobalt is highly corrosive as compared with a conductive material such as copper used as a conventional wiring metal, if a conventional abrasive is used as it is, if cobalt is excessively eroded (etched), slits are formed in the wiring layer Therefore, there is a fear that the conductive metal ions are diffused without functioning as the barrier metal layer. When metal ions are diffused in the insulator, the semiconductor device has a high possibility of short circuit. On the other hand, in order to prevent this, there has been a problem that if the corrosion-resistant agent with a strong corrosion-inhibiting action is added, or if the addition amount of the corrosion-preventing agent is increased, the entire polishing rate is lowered.

As such a problem, an abrasive using a specific metal anticorrosive agent containing two or more double bonds and containing at least one nitrogen atom is known as a heterocyclic compound having 4 to 6 ring atoms See, for example, Patent Document 2). With such an abrasive, it is possible to prevent the slit from entering the wiring layer while protecting the wiring layer.

Japanese Unexamined Patent Application Publication No. 2-278822 Japanese Laid-Open Patent Publication No. 2011-91248

However, with the action of only the metallic anticorrosive agent, etching of cobalt can be suppressed, but at the same time, it is not easy to maintain a high polishing rate for cobalt, and it has been required to further improve the polishing rate for cobalt. An object of the present invention is to provide an abrasive for suppressing the corrosion of the cobalt layer while suppressing the generation of slits while maintaining a good polishing rate for the cobalt layer and a polishing method for a substrate using the same Purpose.

As a result of intensive investigations to solve such conventional problems, the present inventors have found that by using a specific carboxylic acid derivative, the corrosion inhibition property of the cobalt layer is excellent while maintaining a good polishing rate for the cobalt layer, I found out that I can suppress it.

Specific means for solving the above problems are as follows.

<1> A process for producing a carboxylic acid derivative, which comprises at least one carboxylic acid derivative selected from the group consisting of a phthalic acid compound, an isophthalic acid compound and an alkyldicarboxylic acid compound represented by the following general formula (I) And an abrasive for polishing a layer containing cobalt, which contains water and has a pH of 4.0 or less.

HOOC-R-COOH ... (I)

(In the general formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

By using such an abrasive, the corrosion inhibiting property can be improved while maintaining a good polishing rate for the cobalt layer.

(2) at least one carboxylic acid derivative selected from the group consisting of a phthalic acid compound, an isophthalic acid compound, an alkyl dicarboxylic acid compound represented by the following general formula (I), a salt thereof and an acid anhydride, And an abrasive for polishing a layer containing a cobalt element containing water and having a pH of 4.0 or less and an etching rate of 10.0 nm / min or less with respect to cobalt in an abrasive at 50 ° C.

HOOC-R-COOH ... (I)

(In the general formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

By using such an abrasive, the corrosion inhibiting property can be improved while maintaining a good polishing rate for the cobalt layer.

&Lt; 3 &gt; The metal antifoam is the abrasive according to &lt; 1 &gt; or &lt; 2 &gt;, which contains a compound having a triazole skeleton.

This makes it possible to more effectively suppress the corrosion.

<4> The polishing compound according to any one of <1> to <3>, further containing an oxidizing agent.

This makes it possible to further improve the polishing rate of the layer other than the cobalt layer when the film to be polished contains a layer other than the cobalt layer.

<5> The abrasive according to any one of <1> to <4>, further containing an organic solvent.

Thus, when the film to be polished contains a layer other than the cobalt layer, the wettability with respect to the layer other than the cobalt layer is improved, so that the polishing rate can be further improved.

<6> The abrasive according to any one of <1> to <5>, further comprising a water-soluble polymer.

Thereby, the surface to be polished is protected, corrosion is suppressed, and the occurrence of defects such as scratches can be reduced.

<7> The abrasive according to any one of <1> to <6>, further comprising abrasive grains.

This makes it possible to further improve the polishing rate of the layer other than the cobalt layer when the film to be polished contains a layer other than the cobalt layer.

<8> A polishing target film containing a cobalt element formed on at least one surface of a substrate is polished using the polishing agent described in any one of <1> to <7> to remove the excess portion containing the cobalt element And the substrate is polished.

According to the polishing method of the present invention, it becomes possible to polish a film to be polished containing a cobalt element at a high speed while suppressing excessive corrosion.

According to the present invention, it is possible to provide an abrasive excellent in corrosion inhibiting property of a cobalt layer and a polishing method for a substrate using the same, while maintaining a good polishing rate for the cobalt layer.

1 is a schematic sectional view showing a wiring formation process in a conventional damascene process.
2 is a schematic cross-sectional view showing a wiring formation process in a damascene process using a cobalt layer.
3 is a cross-sectional view showing an example of a substrate after polishing by the polishing method of the present invention.

In this specification, the term &quot; process &quot; is included in the term when the intended purpose of the process is achieved, even if it can not be clearly distinguished from other processes, as well as independent processes. The numerical range indicated by "~" indicates a range including numerical values before and after "~" as a minimum value and a maximum value, respectively. The content of each component in the abrasive agent means the total amount of the plurality of substances present in the abrasive agent, unless specifically mentioned, when a plurality of substances corresponding to each component exist in the abrasive agent.

Hereinafter, preferred embodiments of an abrasive (hereinafter simply abbreviated as "abrasive") and a substrate polishing method for polishing a layer containing a cobalt element of the present invention will be described in detail.

[abrasive]

The abrasive of the present invention comprises a carboxylic acid derivative comprising at least one member selected from the group consisting of a phthalic acid compound, an isophthalic acid compound, an alkyldicarboxylic acid compound represented by the following general formula (I) and salts and anhydrides thereof, A metal antiseptic agent, and water, and has a pH of 4.0 or less.

HOOC-R-COOH ... (I)

(In the general formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

&Lt; Carboxylic acid derivative &gt;

The abrasive of the present invention is a polishing compound comprising a phthalic acid compound, an isophthalic acid compound and a dicarboxylic acid compound represented by the above-mentioned general formula (I) (hereinafter, also referred to as a "specific dicarboxylic acid compound") and salts and acid anhydrides thereof (Hereinafter, also referred to as a &quot; specific carboxylic acid derivative &quot;). The above-mentioned specific carboxylic acid derivatives may be used singly or in combination of two or more. By selecting the above specific carboxylic acid derivative among the carboxylic acid and carboxylic acid derivatives present in anhydrous form, the etching rate is controlled appropriately while maintaining a good polishing rate for the cobalt layer, so that the corrosion is suppressed and a good polishing surface Can be obtained. Further, even under more severe conditions (for example, 50 DEG C), the etching rate of the cobalt layer is more effectively suppressed, and excellent corrosion inhibiting properties can be achieved. Here, the excellent corrosion inhibiting property includes that the cobalt layer is etched on the surface to be polished or slits are formed on the wiring layer effectively.

The reason why such an effect is obtained is not clear, but the present inventors have presumed as follows. That is, it is considered that the specific carboxylic acid derivative functions as, for example, a metal dissolver and has an effect of improving the polishing rate for the cobalt layer. At the same time, the specific carboxylic acid derivative simultaneously chelates two carboxyl groups with respect to the cobalt atom to take a cyclic structure, thereby controlling the etching rate so as to form a stable complex state, and has a function of suppressing corrosion on the surface to be polished . In addition, there is a possibility that the formation of the stable complex state contributes to the metal type system described later.

The specific carboxylic acid derivative is selected from the group consisting of a specific dicarboxylic acid compound, a salt thereof, and an acid anhydride thereof from the viewpoints of the polishing rate, the controllability of the etching rate and the corrosion inhibition property to the cobalt layer. In the case of an acidic compound other than the above specific carboxylic acid derivative, it may be difficult to achieve both a good polishing rate for the cobalt layer and suppression of the etching rate of the cobalt layer. This is believed to be because formation of a stable complex state is important as described above, and the steric structure of the acidic compound is an important factor. In addition, even if the above-mentioned specific carboxylic acid derivative is contained, if an acidic compound other than the specific acid compound is contained, the etching rate of the cobalt layer may be remarkably increased. It is considered that this is because the etching effect of the cobalt layer by other acidic compounds is given priority over the formation of the complex state as described above.

The first embodiment of the abrasive according to the present invention is characterized in that the carboxylic acid derivative is selected from the group consisting of a phthalic acid compound, an isophthalic acid compound and a dicarboxylic acid compound represented by the above general formula (I), a salt thereof and an acid anhydride And at least one kind thereof. However, the carboxylic acid derivative may contain a phthalic acid compound, an isophthalic acid compound and a dicarboxylic acid compound other than the dicarboxylic acid compound represented by the general formula (I), a salt thereof And an acid anhydride thereof. The carboxylic acid derivative may be at least one selected from the group consisting of an acid anhydride and an acid anhydride. That is, the carboxylic acid derivative is at least one carboxylic acid derivative selected from the group consisting of a phthalic acid compound, an isophthalic acid compound and a dicarboxylic acid compound represented by the general formula (I), and salts and acid anhydrides thereof And is substantially constituted. Here, "substantially" means a range in which the effect of the present invention is not significantly impaired, and specifically means that the content of the other carboxylic acid derivative is 10 mass% or less with respect to the specific carboxylic acid derivative. The content of the other carboxylic acid derivative is preferably 5 mass% or less, and more preferably 1 mass% or less.

From the same viewpoint, the second embodiment of the abrasive according to the present invention is characterized in that the carboxylic acid derivative is selected from the group consisting of a phthalic acid compound, an isophthalic acid compound and a dicarboxylic acid compound represented by the general formula (I) , And the etching rate for cobalt in an abrasive at 50 캜 is 10.0 nm / min or less. In the second aspect, the carboxylic acid derivative is at least one selected from the group consisting of a phthalic acid compound, an isophthalic acid compound and a dicarboxylic acid compound other than the dicarboxylic acid compound represented by the general formula (I), a salt thereof and an acid anhydride thereof , And it is necessary that the etching rate for cobalt in an abrasive at 50 캜 does not exceed 10.0 nm / min. The preferable ranges of the contents of the other carboxylic acid derivatives are the same as those of the first embodiment.

The etching rate for cobalt in an abrasive at 50 deg. C can be measured as follows. That is, square chips (evaluation chip) of 20 mm in which a 0.3-μm-thick cobalt layer was formed on a silicon substrate were prepared. The chips for evaluation were placed in a beaker containing 50 g of an abrasive, (Film thickness of the cobalt layer before immersion - film thickness of the cobalt layer after immersion) / 1 minute [nm / min] by measuring the film thickness of the cobalt layer before and after immersion.

In the second aspect of the abrasive according to the present invention, the etching rate is 10.0 nm / min or less, and from the viewpoint of improving the corrosion inhibiting property, 9.0 nm / min or less is preferable, and 8.0 nm / min or less is more preferable .

Also in the first aspect of the abrasive according to the present invention, the etching rate is preferably 10.0 nm / min or less, more preferably 9.0 nm / min or less, and more preferably 8.0 nm / min Or less.

Among the specific dicarboxylic acid compounds, the phthalic acid compound includes at least one kind of phthalic acid (benzene-1,2-dicarboxylic acid) and a phthalic acid derivative having at least one substituent group on the benzene ring.

Examples of the substituent include a methyl group, an amino group, and a nitro group. Among them, at least one of a nitro group and a methyl group is preferable, and a nitro group is more preferable.

Specific examples of the phthalic acid compounds include alkylphthalic acids such as phthalic acid, 3-methylphthalic acid and 4-methylphthalic acid, aminophthalic acids such as 3-aminophthalic acid and 4-aminophthalic acid, And nitrophthalic acid. Among them, a phthalic acid compound (nitrophthalic acid) having a nitro group as a substituent is preferable, and at least one of 3-nitrophthalic acid and 4-nitrophthalic acid is more preferable, and 3-nitrophthalic acid is particularly preferable. The phthalic acid compound may be used as an acid anhydride or as a salt.

The isophthalic acid compound includes at least one kind of isophthalic acid (benzene-1,3-dicarboxylic acid) and an isophthalic acid derivative having at least one substituent group on the benzene ring. Examples of the substituent include a nitro group, a methyl group, an amino group, and a hydroxyl group. Among them, a nitro group is preferable.

Specific examples of the isophthalic acid compound include isophthalic acid and 5-nitroisophthalic acid. The isophthalic acid compound may be used as a salt.

The alkyldicarboxylic acid compound represented by the general formula (I) may be an alkyldicarboxylic acid compound having an alkylene group having 4 to 10 carbon atoms. Also, the carbon number is the number of carbon atoms of the alkylene group, and the carbon atom contained in the carboxylic acid group is not counted as the carbon number. The alkylene group may be cyclic, linear, or branched. Among them, it is preferable to be a linear type. From the viewpoints of the polishing rate for the cobalt layer, the controllability of the etching rate and the suppression of corrosion, the number of carbon atoms is preferably 4 to 8, more preferably 4 to 6.

Specific examples of the alkyldicarboxylic acid having an alkylene group having 4 to 10 carbon atoms include adipic acid, pimelic acid, suberic acid and azelaic acid. Among them, adipic acid and pimelic acid are preferable, and pimelic acid is more preferable.

The content of the carboxylic acid derivative is preferably in the range of 0.001% by mass to 10% by mass based on the total mass of the abrasive. By adjusting the content of the carboxylic acid derivative in the above range, a layer other than the cobalt layer formed near the cobalt layer (for example, a metal for wiring such as copper, which is the conductive material layer 5 shown in Fig. , The barrier metal layer 3, and the like) can be obtained.

The content of the carboxylic acid derivative is preferably 0.01 mass% or more, more preferably 0.03 mass% or more, and particularly preferably 0.05 mass% or more, from the viewpoint of the polishing rate. The content of the dicarboxylic acid is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, still more preferably 1.0% by mass or less, from the viewpoint of the etching inhibiting effect and the corrosion inhibiting property of the cobalt layer , 0.7 mass% or less, and most preferably 0.5 mass% or less.

The abrasive is preferably at least one selected from the group consisting of alkylphthalic acid, aminophthalic acid, nitrophthalic acid, isophthalic acid, 5-nitroisophthalic acid and a compound represented by the general formula (I) wherein R is a linear chain having 4 to 8 carbon atoms And at least one member selected from the group consisting of the salts thereof and the acid anhydrides is preferably contained in an amount of 0.01 mass% or more.

It is preferable that the abrasive is at least one selected from the group consisting of alkylphthalic acid, aminophthalic acid, nitrophthalic acid, isophthalic acid, 5-nitroisophthalic acid, and a compound represented by the general formula (I) An alkyl dicarboxylic acid compound which is a linear alkylene group having 4 to 8 carbon atoms, and salts and acid anhydrides thereof in an amount of 5.0 mass% or less.

&Lt; Metal agent &gt;

The metallic antiseptic contained in the abrasive of the present invention is not particularly limited and any compound conventionally known as a metallic anticorrosive agent can be used. Specifically, at least one selected from triazole compounds, pyridine compounds, pyrazole compounds, pyrimidine compounds, imidazole compounds, guanidine compounds, thiazole compounds, tetrazole compounds, triazine compounds and hexamethylene tetramine is used . Here, the term &quot; compound &quot; is a general term for compounds having a skeleton thereof. For example, the triazole compound means a compound having a triazole skeleton.

Examples of the triazole compound include 1,2,3-triazole, 1,2,4-triazole, 3-amino-1H-1,2,4-triazole, benzotriazole, 1-dihydroxypropylbenzotriazole, 2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole, 4-carboxy-1H-benzotriazole, 4-carboxy- (1H-benzotriazole-4-carboxylate), 4-carboxy-1H-benzotriazole butyl ester (1H-benzotriazole- (1H-benzotriazole-4-carboxylate), 5-hexylbenzotriazole, (1,2,3-benzotriazolyl-1-methyl) (2-ethylhexyl) amine, tolyltriazole, naphthotriazole, bis [(1-benzotriazolyl) methyl] phosphonic acid, 3H-1,2,3-triazolo [ 4,5-b] pyridin-3-ol, 1H-1,2,3-triazolo [4,5-b] pyridine, 1-acetyl-1H- [4,5-b] pyridine, 3-hydroxypyridine, 1,2,4-triazolo [1,5-a] pyrimidine, 1,3,4,6,7,8-hexahydro- Methyl-5,7-diphenyl- [1,2,4] triazolo [1,5-a] pyrimidine, 2-methylsulfanyl- , 7-diphenyl- [1,2,4] triazolo [1,5-a] pyrimidine, 2-methylsulfanyl-5,7- 4] triazolo [1,5-a] pyrimidine. In addition, triazole compounds are classified into triazole compounds in the case of having one skeleton and other triazole compounds in one molecule.

Examples of pyridine compounds include 8-hydroxyquinoline, 2-nitropyridin-3-ol, pyridoxamine, nicotinamide, ipronazide, isonicotinic acid, benzo [f] quinoline, 2 4-nitropyridine-1-oxide, pyridine-3-acetic acid ethyl, quinoline, 2-ethylpyridine, quinolinic acid, arecolin, citrafulin , Pyridine-3-methanol, 2-methyl-5-ethylpyridine, 2-fluoropyridine, pentafluoropyridine, 6-methylpyridin-3-ol and ethyl pyridine-2-acetic acid.

Examples of the pyrazole compound include pyrazole compounds such as 1-allyl-3,5-dimethylpyrazole, 3,5-di (2-pyridyl) pyrazole, 3,5-diisopropylpyrazole, Dimethyl-1-hydroxymethylpyrazole, 3,5-dimethyl-1-phenylpyrazole, 3,5-dimethylpyrazole, 3-amino- N-methylpyrazole, 3-aminopyrazole, 3-aminopyrazole and the like.

Examples of the pyrimidine compound include pyrimidine, 1,3-diphenyl-pyrimidine-2,4,6-trione, 1,4,5,6-tetrahydropyrimidine, 2,4,5,6-tetra Aminopyrimidine sulfates, 2,4,5-trihydroxypyrimidine, 2,4,6-triaminopyrimidine, 2,4,6-trichloropyrimidine, 2,4,6-trimethoxypyrimidine , 2,4,6-triphenylpyrimidine, 2,4-diamino-6-hydroxypyrimidine, 2,4-diaminopyrimidine, 2-acetamidopyrimidine, 2-aminopyrimidine, 4- Aminopyrazolo [3,4-d] pyrimidine, and the like.

Examples of the imidazole compound include 1,1'-carbonylbis-1H-imidazole, 1,1'-oxalyldiimidazole, 1,2,4,5-tetramethylimidazole, Dimethylimidazole, 1,2-dimethylimidazole, 1- (3-aminopropyl) imidazole, 1-butylimidazole, 1-ethylimidazole, , Benzimidazole, and the like.

Examples of the guanidine compound include 1,1,3,3-tetramethylguanidine, 1,2,3-triphenylguanidine, 1,3-di-o-tolylguanidine, 1,3-diphenylguanidine, etc. .

Examples of the thiazole compound include 2-mercaptobenzothiazole, 2,4-dimethylthiazole, and the like.

Examples of the tetrazole compound include tetrazole, 5-methyltetrazole, 5-amino-1H-tetrazole, and 1- (2-dimethylaminoethyl) -5-mercaptotetrazole.

Examples of the triazine compound include 3,4-dihydro-3-hydroxy-4-oxo-1,2,4-triazine and the like.

The metallic anticorrosive may be used singly or in combination of two or more kinds. The content of the metal anticorrosive agent is preferably 0.001% by mass to 10% by mass based on the total mass of the polishing slurry since a good polishing rate can be obtained with respect to the polishing target film containing the cobalt element. From the same viewpoint, the content of the metal anticorrosive is more preferably 0.01 mass% or more, and still more preferably 0.02 mass% or more. From the same viewpoint, the content of the metal anticorrosive is more preferably 5.0 mass% or less, and still more preferably 0.5 mass%.

The metal anticorrosion agent is combined with the carboxylic acid derivative to polish the cobalt layer at an appropriate rate while remarkably suppressing the etching rate of the cobalt layer even under severe temperature conditions (for example, 50 DEG C) Enabling the corrosion inhibition of the cobalt layer. It is considered that this is because, for example, the metal anticorrosive agent exhibits excellent function as a complexing agent and a film protecting agent in coexistence with the specific dicarboxylic acid compound.

In view of the above, at least one member selected from the group consisting of a triazole compound, a pyridine compound, an imidazole compound, a tetrazole compound, a triazine compound and hexamethylenetetramine is preferable, 4,5-b] pyridin-3-ol, 1-hydroxybenzotriazole, 1H-1,2,3-triazolo [4,5-b] pyridine, benzotriazole Dihydro-3-hydroxy-4-oxo-l, 2,4-triazine, and hexaaryl compounds such as 3-hydroxypyridine, benzimidazole, Methylene tetramine, and the like.

The ratio of the carboxylic acid derivative to the metal anticorrosive agent (carboxylic acid derivative / metal anticorrosive agent) in the abrasive is preferably in the range of 10/1 to 1/5 (in terms of mass ratio) from the viewpoint of satisfactorily controlling the etching rate and the polishing rate , More preferably in the range of 7/1 to 1/5, further preferably in the range of 5/1 to 1/5, particularly preferably in the range of 5/1 to 1/1 .

Further, from the viewpoint of controlling the etching rate and the polishing rate well, the above-mentioned abrasive is preferably selected from the group consisting of a carboxylic acid derivative and a triazole compound, a pyridine compound, an imidazole compound, a tetrazole compound, a triazine compound and hexamethylenetetramine (Carboxylic acid derivative / metal anticorrosive) of at least one kind of metal anticorrosion agent selected from the group consisting of a metal element and a metal element is preferably 10/1 to 1/5,

The ratio of the carboxylic acid derivative to at least one metal corrosion inhibitor selected from the group consisting of a triazole compound, a pyridine compound, an imidazole compound, a tetrazole compound, a triazine compound and hexamethylenetetramine (a carboxylic acid derivative / Metal anticorrosive) is more preferably 5/1 to 1/5,

The carboxylic acid derivative is reacted with 3H-1,2,3-triazolo [4,5-b] pyridin-3-ol, 1-hydroxybenzotriazole, 1H-1,2,3-triazolo [ , 5-b] pyridine, benzotriazole, and other triazole compounds such as 3-hydroxypyridine, benzimidazole, 5-amino-1H-tetrazole, 3,4-dihydro- (Carboxylic acid derivative / metal anticorrosive) of at least one metal anticorrosive selected from the group consisting of 1,2,4-triazine, 1,2,4-triazine and hexamethylenetetramine is preferably 5/1 to 1/1 desirable.

<Oxidant>

It is preferable that the abrasive further contains at least one oxidizing agent. By further containing an oxidizing agent, the polishing rate of the layer other than the cobalt layer can be further improved. The oxidizing agent is not particularly limited and can be appropriately selected from commonly used oxidizing agents. Specific examples thereof include hydrogen peroxide, peroxosulfuric acid, nitric acid, potassium periodate, hypochlorous acid, ozonated water and the like, among which hydrogen peroxide is preferable. These metal oxidants may be used singly or in combination of two or more.

When the abrasive contains an oxidizing agent, the content of the metal oxidizing agent is preferably 0.01% by mass to 50% by mass in the total mass of the abrasive. The content is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, from the viewpoint of preventing the oxidation of the metal from becoming insufficient and from lowering the polishing rate. Further, it is more preferably 30% by mass or less, and further preferably 15% by mass or less, from the viewpoint that roughness on the surface to be polished can be prevented.

<Organic solvents>

The abrasive may further contain an organic solvent. By the addition of the organic solvent, the wettability of the layer other than the cobalt layer formed in the vicinity of the cobalt layer can be improved, and the polishing rate can be further improved. The organic solvent is not particularly limited, but is preferably water-soluble. Here, water solubility is defined as dissolving 0.1 g or more at 25 DEG C per 100 g of water.

Examples of the organic solvent include carbonic ester solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; lactone solvents such as butyl lactone and propyl lactone; ethylene glycol, propylene glycol, Glycol solvents such as glycerol, dipropylene glycol, triethylene glycol, tripropylene glycol and the like; ethers such as tetrahydrofuran, dioxane, dimethoxyethane, polyethylene oxide, ethylene glycol monomethyl acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl Ether solvents such as acetone and ether acetate; alcohol solvents such as methanol, ethanol, propanol, n-butanol, n-pentanol, n-hexanol, isopropanol and 3-methoxy- Ketone solvents such as ketone, etc .; ketones such as dimethylformamide, N-methylpyrrolidone, ethyl acetate, Ethyl, it can be given other organic solvent such as sulfolane.

The organic solvent may be a glycol solvent derivative. For example, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monoethyl ether, Propylene glycol monoethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether, tripropylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol monopropyl ether, diethylene glycol mono Propylene glycol monopropyl ether, triethylene glycol monopropyl ether, tripropylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, diethylene glycol monobutyl ether, tripropylene glycol monobutyl ether, triethylene glycol Propylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, triethylene glycol dimethyl ethyl ether, tripropylene glycol ether, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, Dimethyl ether, ethylene glycol diethyl ether, propylene glycol diethyl ether, diethylene glycol diethyl ether, dipropylene glycol diethyl ether, triethylene glycol diethyl ether, tripropylene glycol diethyl ether, ethylene glycol dipropyl ether, propylene Diethylene glycol diisopropyl ether, diethylene glycol diisopropyl ether, diethylene glycol diisopropyl ether, diethylene glycol diisopropyl ether, triethylene glycol dipropyl ether, tripropylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dibutyl ether, diethylene And the like can be recalled dibutyl ether, dipropylene glycol dibutyl ether, triethylene glycol dibutyl ether, tripropylene glycol butyl ether and glycol ether solvents.

Among them, at least one selected from a glycol solvent, a glycol solvent derivative, an alcohol solvent and a carbonic acid ester solvent is preferable, and at least one selected from alcohol solvents is more preferable. These organic solvents may be used alone or in combination of two or more.

When the abrasive contains an organic solvent, the content of the organic solvent is preferably 0.1% by mass to 95% by mass in the total mass of the abrasive. The content of the organic solvent is more preferably 0.2 mass% or more, and still more preferably 0.5 mass% or more, from the viewpoint of preventing the wettability of the abrasive with respect to the substrate. Further, it is more preferably 50% by mass or less, and still more preferably 10% by mass or less, from the viewpoint of preparation, use, treatment of wastewater, etc. of the abrasive.

<Water-soluble polymer>

The abrasive preferably includes at least one water-soluble polymer. This makes it possible to more effectively suppress the corrosion effect, protect the film surface, and reduce the occurrence of defects. Here, the water-solubility is defined as dissolving at least 0.1 g per 100 g of water at 25 캜.

Examples of the water-soluble polymer include a water-soluble polymer having a carboxylic acid group or a carboxylate group. Examples of such a water-soluble polymer include homopolymers of monomers having carboxylic acid groups such as acrylic acid, methacrylic acid and maleic acid, homopolymers in which the carboxylic acid group portion of the polymer is a carboxylate group such as an ammonium salt, and the like have. A copolymer of a monomer having a carboxylic acid group and a monomer having a carboxylate group and an alkyl ester of a carboxylic acid or the like is also preferable. Specific examples of the water-soluble polymer include polymers in which at least a part of the carboxylic acid groups of polyacrylic acid and polyacrylic acid are substituted with carboxylic acid ammonium salt groups (hereinafter referred to as "polyacrylic acid ammonium salt").

Examples of other water-soluble polymers other than the above include polysaccharides such as alginic acid, pectic acid, carboxymethylcellulose, agar, cardron, and pullulan; polyaspartic acid, polyglutamic acid, polylysine, Polycarboxylic acids and salts thereof such as acid, polyamidic acid ammonium salt, sodium polyamide acid salt and polyglyoxylic acid, and vinyl-based polymers such as polyvinyl alcohol, polyvinylpyrrolidone and polyacrolein.

When the substrate to be polished is a silicon substrate for a semiconductor integrated circuit or the like, it is preferable that the water-soluble polymer is a polymer having an acidic group or an ammonium salt thereof from the time of avoiding contamination by alkali metals, alkaline earth metals, halides and the like. However, the case where the substrate to be polished is a glass substrate or the like is an exception.

Among the above-mentioned water-soluble polymers, the water-soluble polymer having a carboxylic acid group or a carboxylate group, a group consisting of a water-soluble polymer having a carboxylic acid group or a carboxylate group, a pectic acid, agar, polymaleic acid, polyacrylamide, polyvinyl alcohol and polyvinylpyrrolidone Soluble polymers (including esters and salts) having a carboxylic acid group or a carboxylate group are more preferable, and polyacrylic acid (including salts thereof) ) Is more preferable, and a polyacrylic acid ammonium salt is particularly preferable. These may be used alone or in combination of two or more.

The weight average molecular weight of the water-soluble polymer is preferably from 500 to 1,000,000, more preferably from 1,000 to 500,000, even more preferably from 2,000 to 200,000, and particularly preferably from 5,000 to 150,000.

The weight average molecular weight can be measured, for example, by gel permeation chromatography (GPC) based on the following method and using a value converted to standard polyacrylic acid.

(Condition)

Sample: 10 μl

Standard polyacrylic acid: manufactured by Hitachi Chemical Co., Ltd. Product name: PMAA-32

Detector: RI-monitor manufactured by Hitachi, Ltd., trade name "L-3000"

Intergator: manufactured by Hitachi, Ltd., GPC Intergator, trade name "D-2200"

Pump: Product name "L-6000", manufactured by Hitachi, Ltd.

Degassing apparatus: manufactured by Showa Denko KK, product name "Shodex DEGAS"

Column: "GL-R440", "GL-R430", and "GL-R420", trade names, manufactured by Hitachi Chemical Co.,

Eluent: tetrahydrofuran (THF)

Measuring temperature: 23 ° C

Flow rate: 1.75 ml / min

Measurement time: 45 minutes

When the abrasive contains a water-soluble polymer, the content of the water-soluble polymer is preferably 0.001% by mass to 10% by mass in the total mass of the abrasive. Is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.02% by mass or more from the viewpoint of securing favorable corrosion inhibiting properties. Further, it is preferably 10 mass% or less, more preferably 5.0 mass% or less, and even more preferably 1.0 mass% or less, from the viewpoint of maintaining a sufficient polishing rate.

<Abrasive grain>

The abrasive preferably includes at least one kind of abrasive. By including the abrasive grains, the polishing rate of the layer other than the cobalt layer formed in the vicinity of the cobalt layer can be improved.

The main abrasive grains include, for example, inorganic abrasive grains such as silica, alumina, zirconia, ceria, titania, germania and silicon carbide; and organic abrasive grains such as polystyrene, polyacrylic and polyvinyl chloride. Among them, inorganic abrasive grains selected from the group consisting of silica, alumina, zirconia, ceria, titania and germania are preferable, and in particular, inorganic abrasive grains selected from the group consisting of silica and alumina are more preferable.

Of the inorganic abrasive grains selected from the group consisting of silica and alumina, colloidal silica or colloidal alumina is preferable because of good dispersion stability in the abrasive and low occurrence of polishing scratches (scratches) generated by CMP , And colloidal silica is more preferable. These abrasives may be used alone or in combination of two or more.

The average particle diameter of the abrasive grains is preferably from 10 nm to 100 nm, more preferably from 20 nm to 90 nm, and even more preferably from 40 nm to 80 nm, from the viewpoint of obtaining a good polishing rate.

The average particle size of the abrasive grains is a value measured by a light diffraction scattering particle size distribution meter (for example, COULTER N4SD manufactured by COULTER Electronics). Coulter's measurement conditions were a measurement temperature of 20 ° C, a solvent refractive index of 1.333 (equivalent to water), a particle refractive index of Unknown (setting), a solvent viscosity of 1.005 mPa · s (equivalent to water), a Run Time of 200 sec, Intensity (corresponding to scattering intensity, turbidity) should be in the range of 5E + 04 to 4E + 05, and higher than 4E + 05 should be diluted with water.

When the abrasive contains abrasive grains, the content of the abrasive grains is preferably 1.0 mass% or more, more preferably 3.0 mass% or more, and further preferably 3.0 mass% to 5.0 mass%, in the total mass of the abrasive. By setting the content of the abrasive grains in the above range, a good polishing rate can be obtained.

<Water>

The water used in the present invention is not particularly limited, but pure water can be preferably used. The water may be blended as the remainder of the constituent material of the above-mentioned abrasive, and the content thereof is not particularly limited.

<Others>

Other components that can be added to the abrasive include, for example, a colorant such as a surfactant, a dye such as Victoria pure blue, a pigment such as phthalocyanine green, and the like.

The pH of the abrasive is 4.0 or less. If the pH exceeds 4.0, there is a fear that the polishing rate of the conductive material layer made of the wiring metal and the cobalt layer will be lowered. On the other hand, the above pH is preferably 1.0 or more, and more preferably 2.0 or more, from the viewpoint of gradually suppressing the corrosion of the wiring metal and solving the difficulties in handling due to strong acidity.

The pH can be adjusted by the addition amount of the acidic compound. It can also be adjusted by addition of an alkaline compound such as ammonia, sodium hydroxide or tetramethylammonium hydroxide (TMAH).

The pH of the abrasive is measured by a pH meter (for example, Model F-51 manufactured by HORIBA, Ltd.). After three-point calibration using a standard buffer (phthalate pH buffer 4.21 (25 占 폚), neutral phosphate pH buffer pH 6.86 (25 占 폚) and borate pH buffer pH 9.04 (25 占 폚) , And the value after stabilization after 3 minutes or more can be measured.

The abrasive may be stored as an abrasive (storage liquid) containing a carboxylic acid derivative, a metal anti-corrosive agent and water, and the abrasive may be mixed with other constituent materials and water appropriately at the time of polishing. Alternatively, it may be stored in the form of an abrasive compound containing a suitable constituent material in a carboxylic acid derivative, a metal anticorrosive agent and water.

The abrasive can be applied to formation of a wiring layer in a semiconductor device. The polishing target film to be polished may contain at least a portion containing a cobalt element (hereinafter referred to as a &quot; cobalt portion &quot;) and may further include a conductive material, a barrier metal, or an insulator formed in the vicinity of the cobalt portion.

That is, another aspect of the present invention relates to a method for producing a carboxylic acid compound represented by the following general formula (I), which comprises at least one carboxylic acid selected from the group consisting of a phthalic acid compound, an isophthalic acid compound, Is a use for polishing a layer containing a cobalt element of an abrasive having a pH of 4 or less and containing a metal salt, a derivative, a metal antiseptic agent, and water.

HOOC-R-COOH ... (I)

(In the general formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

In another aspect of the present invention, there is provided a process for producing a carboxylic acid compound, which comprises reacting at least one carboxylic acid selected from the group consisting of a phthalic acid compound, an isophthalic acid compound and an alkyl dicarboxylic acid compound represented by the following general formula (I) A polishing agent for polishing a layer containing a cobalt element, which contains a derivative, a metal anticorrosive, and water and has a pH of 4.0 or less and an etching rate of 10.0 nm / min or less at 50 캜 for cobalt, to be.

HOOC-R-COOH ... (I)

(In the general formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

[Polishing method of substrate]

A polishing method for a substrate of the present invention is a polishing method for polishing a target polishing film containing a cobalt element formed on at least one surface of a substrate by using the above polishing agent to remove an excess portion containing a cobalt element. More specifically, while supplying the above-mentioned abrasive between a polishing target film containing a cobalt element formed on at least one surface of a substrate and a polishing cloth on the polishing platen, the surface of the substrate on the side where the polishing target film is formed is polished And at least a part of the film to be polished is removed by relatively moving the substrate and the polishing platen.

Hereinafter, a series of steps of forming a wiring layer in a semiconductor device using the polishing method of the substrate of the present invention will be described with reference to FIG. However, the use of the abrasive of the present invention is not limited to the following process.

2 (a), the substrate 10 before polishing has an insulator 2 having recesses of a predetermined pattern on the silicon substrate 1 and an insulator (not shown) along the irregularities of the surface of the insulator 2 A barrier metal layer 3 covering the barrier metal layer 3 and a cobalt layer 4 covering the barrier metal layer 3. The conductive material layer 5 is formed on the cobalt layer 4. [

Examples of the insulator 2 include a silicon-based insulator and an organic polymer-based insulator. Examples of the silicon-based insulator include silica-based insulators such as silicon dioxide, fluorosilicate glass, organosilicate glass obtained by using trimethylsilane or dimethoxydimethylsilane as a starting material, silicon oxynitrides, hydrogenated silsesquioxane, Silicon nitride, and the like. Examples of the organic polymer-based insulator include all-aromatic low-dielectric-constant insulators. Of these, silicon dioxide is particularly preferable.

The insulator 2 is formed by a CVD (chemical vapor deposition) method, a spin coating method, a dip coating method, or a spray method. Specific examples of the insulator 2 include an insulator in an LSI manufacturing process, particularly, a multilayer wiring formation process.

The barrier metal layer 3 is formed in order to prevent the conductive material into the insulator 2 from diffusing and to improve the adhesion between the insulator 2 and the conductive material layer 5. Examples of the barrier metal used for the barrier metal layer 3 include tantalum compounds such as tantalum, tantalum nitride and tantalum alloy, titanium compounds such as titanium, titanium nitride and titanium alloy, tungsten compounds such as tungsten, tungsten nitride and tungsten alloy, And the like. The barrier metal layer 3 may be a single layer structure made of one of these, or a laminated structure composed of two or more kinds. The barrier metal layer 3 is formed by vapor deposition, CVD (chemical vapor deposition) or the like. Alternatively, only the cobalt layer 4 may be formed as the barrier metal layer 3.

Examples of the cobalt used in the cobalt layer 4 include cobalt, cobalt alloy, oxide of cobalt, oxide of cobalt alloy, and the like. The cobalt layer is formed by a known sputtering method or the like.

Examples of the conductive material used for the conductive material layer 5 include copper, a copper alloy, an oxide of copper, an oxide of a copper alloy, a metal containing copper as a main component, a tungsten metal such as tungsten and tungsten alloy, Noble metals, and the like. Among them, a metal mainly composed of copper such as copper, a copper alloy, an oxide of copper, and an oxide of a copper alloy is preferable. The conductive material layer 5 is formed by a known sputtering method, a plating method, or the like.

The thickness of the barrier metal layer 3 is about 0.01 to 2.5 m and the thickness of the cobalt layer 4 is about 0.01 to 2.5 m and the thickness of the insulating material 2 is about 0.01 to 2.0 m, The thickness of the substrate 5 is preferably about 0.01 탆 to 2.5 탆.

In the first polishing step of polishing the conductive material layer 5 from the state shown in Fig. 2 (a) to the state shown in Fig. 2 (b), the conductive material layer 5 on the surface of the substrate 10 before polishing, For example, an abrasive for a conductive material having a sufficiently large polishing rate ratio of the conductive material layer 5 / the cobalt layer 4 is used for polishing by CMP. Thereby, the substrate 20 having the conductor pattern in which the cobalt layer 4 of the convex portion on the substrate is exposed on the surface and the conductive material layer 5 is left in the concave portion is obtained. As the abrasive for the conductive material having a sufficiently large polishing rate ratio of the conductive material layer 5 / the cobalt layer 4, for example, the abrasive described in Japanese Patent No. 3337464 can be used. In the first polishing step, a part of the convex cobalt layer 4 may be polished together with the conductive material layer 5.

In the succeeding second polishing step, the conductor pattern obtained by the first polishing step is used as the film to be polished for the second polishing step and polished using the polishing agent of the present invention.

In the second polishing step, by moving the polishing platen and the substrate 20 relative to each other while feeding the abrasive of the present invention between the polishing cloth and the substrate while the substrate 20 is being pressed onto the polishing cloth of the polishing platen, The cobalt layer 4 exposed by the first polishing step is polished.

As a polishing apparatus, a general polishing apparatus having a polishing table attached with a holder for holding a substrate to be polished and a motor capable of changing the number of rotations, and the polishing cloth is attached can be used. As the polishing cloth, general nonwoven fabric, foamed polyurethane, porous fluororesin and the like can be used, and there is no particular limitation.

The polishing conditions are not particularly limited, but it is preferable that the rotation speed of the polishing platen be as low as 200 rpm or less so that the substrate does not protrude. The pressing pressure on the polishing cloth of the substrate having the polishing target film is preferably 1 to 100 kPa, more preferably 5 to 50 kPa to satisfy the uniformity of the polishing speed of the polishing target surface and the flatness of the pattern. desirable.

While polishing, the abrasive of the present invention is continuously supplied between the polishing cloth and the polished film by a pump or the like. The supply amount is not limited, but it is preferable that the surface of the polishing cloth is always covered with an abrasive. It is preferable that the substrate after the polishing is thoroughly washed in an oil bath and then dried by dropping water droplets adhering to the substrate using a spin dryer or the like.

In the second polishing step, at least the exposed cobalt layer 4 is polished to remove excess cobalt. In the second polishing step, the cobalt layer 4 may be polished, the polishing may be terminated when the barrier metal layer 3 is exposed, and the barrier metal layer 3 may be polished by an abrasive for polishing the barrier metal layer. As shown in FIG. 2 (b) to FIG. 2 (c), the barrier metal layer 3 may be polished in series from the cobalt layer 4 in the second polishing step. The conductive material layer 5 buried in the recess may be polished together with the cobalt layer 4 and the barrier metal layer 3.

The insulating material 2 under the barrier metal layer 3 of the convex portion is entirely exposed and the conductive material layer 5 to be the wiring layer is left in the concave portion and the barrier metal layer 3 and the cobalt layer Polishing is terminated at the time when the substrate 30 having a desired pattern in which the cross section of the substrate 30 is exposed is exposed.

In order to ensure better flatness at the end of polishing, as shown in Fig. 3, in the case of over-polishing (for example, when the time until the desired pattern is obtained in the second polishing step is 100 seconds, It is also possible to add 50 seconds for polishing and 50% for over-polishing.) In the case of over-polishing, a part of the insulator 2 is also removed by polishing.

After the metal wiring thus formed, a second layer insulator and a metal wiring are formed and then polished to form a smooth surface over the entire surface of the semiconductor substrate. By repeating this process a predetermined number of times, a semiconductor device having a desired number of wiring layers can be manufactured.

The abrasive of the present invention can be used not only to polish a metal film formed on a semiconductor substrate, but also to polish a substrate such as a magnetic head.

Example

Hereinafter, the present invention will be described concretely with reference to examples, but the present invention is not limited to these examples.

<Evaluation of etching amount for cobalt>

[Examples and Comparative Examples]

(Method of manufacturing abrasive article)

The amounts of the metal antiseptics and carboxylic acid derivatives shown in Tables 1 and 2 were added to the container so as to be the final abrasive as shown in Table 1, and the amount of the polyacrylic acid ammonium salt (manufactured by Hitachi Chemical Co., Ltd., molecular weight 8000) as an ultimate abrasive in an amount of 0.02 mass%, and an organic solvent in an amount of 3 mass% of 3-methoxy-3-methyl-1-butanol as a final abrasive in an amount of 1.4 mass% Mixed to dissolve the entire ingredients.

Next, colloidal silica (manufactured by Fuso Kagaku Kogyo Co., Ltd., particle size of 60 nm), which is silica particles, was added in an amount corresponding to 4.0 mass% of the total mass of the slurry to be prepared, and further slurry was obtained along with ultrapure water . To the total mass of the obtained slurry, hydrogen peroxide solution of 30 mass% was added so as to be 0.2 mass%, and various kinds of polishing slurry were obtained.

The pH of each of the obtained abrasives was measured and shown in Tables 1 and 2.

(Evaluation of etching amount for cobalt)

A blanket substrate (a) in which a cobalt layer having a thickness of 300 nm was formed on an 8-inch silicon substrate by the CVD method was prepared. The blanket substrate (a) was cut into 20 mm square chips to prepare an evaluation chip (b).

The evaluation chip (b) was placed in a beaker containing 50 g of each of the abrasives described above, and immersed in a thermostatic chamber at 50 ° C for 1 minute. The evaluation chip (b) after immersion was taken out, sufficiently washed with pure water, and then nitrogen gas was blown to dry the moisture on the chip. The resistance of the evaluation chip (b) after drying was measured by a resistivity meter and converted into the film thickness of the cobalt layer after immersion by the following equation (1).

Calibration curves were obtained from the information of the resistance values corresponding to the respective film thicknesses of the blanket substrate (a), and the film thickness of the cobalt layer was obtained from the following equation (1).

The film thickness [nm] of the cobalt layer after immersion

= 104.5 占 (the resistance value of the evaluation chip (b) [m?] / 1000) ^-0.893 (One)

Then, the etching rate of the cobalt layer was determined from the obtained film thickness of the cobalt layer after immersion and the thickness of the cobalt layer before immersion by the following equation (2).

Cobalt layer etching rate (Co-ER) [nm / min]

= (Film thickness [nm] of the cobalt layer before immersion - film thickness [nm] of the cobalt layer after immersion) / 1 minute (2)

For each of the abrasives obtained above, the etching rate for the cobalt layer was determined. The results are shown in Tables 1 and 2. In Table 1 and Table 2, "-" in the column of the carboxylic acid derivative and the metal anticorrosive indicates that it is unmixed.

(Evaluation of polishing rate against cobalt)

The polishing rate (Co-RR) [nm / min] when the blanket substrate (a) was polished under the following conditions by using each of the abrasives obtained above was evaluated. The results are shown in Tables 1 and 2 together. In addition, in some of the comparative examples, since the etching rate was too fast, the evaluation of the polishing rate was omitted and marked with "-".

<Polishing Condition>

Grinding cloth: IC 1000

Polishing pressure: 10.3 ㎪ (1.5 psi)

Number of revolutions: Platen / head = 93/87 rpm

Feed rate of abrasive: 200 ml / min

Polishing time: 0.5 minutes

Polishing temperature: 50 캜

As is clear from Tables 1 and 2, in Examples 1 to 13, since the specific dicarboxylic acid and the metal anticorrosive agent are contained at the same time, the etching rate of cobalt is remarkably suppressed even under the condition of 50 캜, And it was found that polishing was possible at a high speed. From this point of view, it is suggested that the specific dicarboxylic acid compound of the present invention containing the carboxylic acid derivative has a function as a complexing agent and an anticorrosive agent. That is, according to the polishing slurry of the present invention, when a layer containing a cobalt element is polished, the layer containing the cobalt element is excessively etched at a good polishing rate or slit caused by corrosion is effectively suppressed It is suggested that polishing is possible.

1 silicon substrate
2 Isolator
3 barrier metal layer
4 cobalt layer
5 Conductive material layer (metal for wiring)

Claims (13)

A carboxylic acid derivative comprising at least one kind selected from the group consisting of a phthalic acid compound having at least one substituent on a benzene ring, an isophthalic acid compound having at least one substituent on a benzene ring, and salts and acid anhydrides thereof; An abrasive | polishing agent for grind | polishing the layer containing cobalt element which contains an agent and water and whose pH is 4.0 or less. At least one carboxylic acid derivative selected from the group consisting of a phthalic acid compound having one or more substituents on the benzene ring, an isophthalic acid compound having one or more substituents on the benzene ring, and salts and acid anhydrides thereof; And an abrasive for polishing a layer containing cobalt element containing water and having a pH of 4.0 or less and an etching rate with respect to cobalt at 50 ° C of 10.0 nm / min or less. The method of claim 1,
The phthalic acid compound,
The abrasive | polishing agent which has at least 1 sort (s) chosen from the group which consists of a methyl group, an amino group, and a nitro group as a substituent. The method of claim 1,
The isophthalic acid compound,
The abrasive | polishing agent which has at least 1 sort (s) chosen from the group which consists of a nitro group, a methyl group, an amino group, and a hydroxyl group as a substituent. The method of claim 1,
The phthalic acid compound is at least one selected from the group consisting of 3-methylphthalic acid, 4-methylphthalic acid, 3-aminophthalic acid, 4-aminophthalic acid, 3-nitrophthalic acid and 4-nitrophthalic acid, and salts and acid anhydrides thereof. Abrasive containing The method of claim 1,
The said isophthalic acid compound contains at least 1 sort (s) chosen from the group which consists of 5-nitroisophthalic acid and its salt. 3. The method of claim 2,
The phthalic acid compound,
The abrasive | polishing agent which has at least 1 sort (s) chosen from the group which consists of a methyl group, an amino group, and a nitro group as a substituent. 3. The method of claim 2,
The isophthalic acid compound,
The abrasive | polishing agent which has at least 1 sort (s) chosen from the group which consists of a nitro group, a methyl group, an amino group, and a hydroxyl group as a substituent. 3. The method of claim 2,
The phthalic acid compound is at least one selected from the group consisting of 3-methylphthalic acid, 4-methylphthalic acid, 3-aminophthalic acid, 4-aminophthalic acid, 3-nitrophthalic acid and 4-nitrophthalic acid, and salts and acid anhydrides thereof. Abrasive containing 3. The method of claim 2,
The said isophthalic acid compound contains at least 1 sort (s) chosen from the group which consists of 5-nitroisophthalic acid and its salt. 11. The method according to any one of claims 1 to 10,
Wherein the metal anticorrosive comprises a compound having a triazole skeleton. 11. The method according to any one of claims 1 to 10,
Further comprising at least one selected from the group consisting of an oxidizing agent, an organic solvent, a water-soluble polymer, and abrasive grains. The substrate to which the to-be-polished film containing the cobalt element formed in the at least one surface of the board | substrate is polished using the abrasive | polishing agent in any one of Claims 1-10, and the excess part containing a cobalt element is removed. Polishing method.

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