KR20130011943A - Polishing agent and method for substrate - Google Patents

Abstract

PURPOSE: A polishing agent and a polishing method of a substrate are provided to provide a cobalt layer excellent corrosion resistance while maintaining sufficient polishing rate. CONSTITUTION: A polishing agent for polishing a cobalt-containing layer comprises: a carboxylic acid derivative which has at least one carboxylic acid selected from a phthalic acid compound, an isophthalic acid compound, an alkyldicarboxylic acid compound indicated in chemical formula 1: HOOC-R-COOH, and a salt and acid anhydride thereof; a metal anticorrosive agent; and water. The pH of the polishing agent is 4.0 or less. In chemical formula 1, R is a C4-10 alkylene group. A polishing method of a substrate comprises: a step of polishing at least one cobalt-containing polishing target film on the substrate(1) by using the polishing agent to remove residual parts except for a part containing cobalt atoms.

Description

Polishing method of abrasive and substrate {POLISHING AGENT AND METHOD FOR SUBSTRATE}

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

In recent years, with the integration and high performance of semiconductor integrated circuits (hereinafter, referred to as "LSI"), new microfabrication technologies have been developed. Chemical mechanical polishing (hereinafter, referred to as "CMP") is also a technique that is frequently used in the planarization of insulators, metal plug formation, buried wiring formation, and the like in the LSI manufacturing process, particularly in the multilayer wiring formation process.

In recent years, in order to improve the performance of LSI, the use of a copper alloy has been attempted as a wiring material. However, the copper alloy is difficult to be finely processed by the dry etching method frequently used in the formation of conventional aluminum alloy wirings. Thus, for example, a so-called damascene method is mainly employed in which a copper alloy thin film is deposited and buried on an insulating film in which grooves are formed in advance, and a copper alloy thin film other than the groove portion is removed by CMP to form a buried wiring. See, for example, Patent Document 1.).

In the general method of CMP of metal, a polishing cloth is affixed on a circular polishing plate (platen), the surface of the polishing cloth is immersed in a liquid metal polishing agent, and the surface on which the metal film of the substrate is formed is pressed. The polishing platen is rotated in a state where a predetermined pressure (hereinafter referred to as "polishing pressure") is applied to remove the metal film of the convex portion by mechanical friction between the metal abrasive and the convex portion of the metal film.

The abrasive | polishing agent for metals used for CMP generally contains an oxidizing agent and an abrasive grain, and a metal solubilizer, a metal anticorrosive agent, etc. are further added as needed. When these are added, it is thought that the basic mechanism is to oxidize the surface of the metal film according to the metal solubilizer and to shave the oxide layer by the abrasive grains. Since the oxide layer on the surface of the metal film, which becomes a concave portion, does not rub against the polishing cloth very much, and the effect of shaving by the abrasive grains is not effective, the metal layer of the convex portion is removed and the substrate surface is planarized with the progress of CMP. have.

On the other hand, as shown to Fig.1 (a), in the lower layer of the conductive material layer 5 which consists of metals for wiring, such as copper or a copper alloy, copper diffusion prevention in the insulator 2 formed on the silicon substrate 1 is prevented. And a barrier metal conductor film (hereinafter referred to as "barrier metal layer 3") for improving adhesion. Therefore, it is necessary to remove the exposed barrier metal layer 3 by CMP except the wiring part in which the wiring metal is embedded.

Therefore, the "first polishing process" for polishing the conductive material layer 5 from the state shown in Fig. 1A to the state shown in Fig. 1B, and Fig. 1C in the state shown in Fig. 1B. The two-stage polishing method which divides into the "2nd grinding | polishing process" which grind | blocks the barrier metal layer 3 to the state shown in (), and grinds with a different abrasive | polishing agent, is generally applied.

By the way, with the refinement of a design rule, each layer of the said wiring formation process also tends to become thin. However, the said barrier metal layer 3 becomes thin, and the effect which prevents the diffusion of the electrically-conductive substance containing at least 1 sort (s) chosen from copper or a copper alloy and these oxides falls, for example. Moreover, as wiring width becomes narrow, the embedding property of a conductive material falls, and the void | gap called a void generate | occur | produces in a wiring part. In addition, adhesion with the conductive material layer also tends to decrease. For this reason, replacing the metal used for the barrier metal layer 3 in FIG. 1 with the metal containing Co (cobalt) element is examined. As shown in Fig. 2 (a), a layer of metal containing cobalt element (hereinafter referred to as "cobalt layer 4") is formed between the barrier metal layer 3 and the conductive material layer 5. It is also proposed to interpose. By using the cobalt layer 4, diffusion of the conductive material is suppressed, and cobalt has a high affinity with copper widely used as the conductive material, so that the embedding of the copper layer to the wiring portion is improved, and further, copper Adhesion with the layer can be supplemented.

In the case of using cobalt as the barrier metal layer, the abrasive for metal needs to remove the extra cobalt layer. Various kinds of abrasives for metals are known. On the other hand, when there is any metal abrasive, it cannot be said that any metal can be removed. As conventional abrasives for metals, it is known to use metals such as copper, tantalum, titanium, tungsten, and aluminum as targets for removal (extra parts), but abrasives for cobalt are not known. .

However, cobalt is more corrosive than conductive materials such as copper, which has been used as a conventional wiring metal, so that if a conventional abrasive is used as it is, cobalt may be excessively eroded (etched) or slits may be formed in the wiring layer. Therefore, there is a fear that the conductive metal ions are diffused without functioning as a barrier metal layer. When metal ions diffuse into the insulator, the semiconductor device is more likely to be shorted. On the other hand, in order to prevent this, when the anticorrosive with strong anticorrosive action is added, or when the addition amount of an anticorrosive agent is added, there existed a subject that the whole grinding | polishing rate will fall.

For such a problem, as a heterocyclic compound of 4 to 6 membered rings, an abrasive using a specific metal anticorrosive agent containing two or more double bonds and one or more nitrogen atoms is known ( For example, see patent document 2.). According to such an abrasive, it becomes possible to prevent a slit from entering into a wiring layer, protecting a wiring layer.

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

However, with the action of only the metal anticorrosive, it is possible to suppress the etching of cobalt, 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. The present invention is to solve the above problems, to provide an abrasive and a substrate polishing method using the same, while suppressing the corrosion of the cobalt layer, while suppressing the corrosion of the cobalt layer while maintaining a good polishing rate for the cobalt layer. Purpose.

As a result of earnestly examining in order to solve such a conventional problem, the present inventors use the specific carboxylic acid derivative, and it is excellent in the corrosion inhibitory property of a cobalt layer, maintaining the favorable grinding | polishing rate with respect to a cobalt layer, and the generation | occurrence | production of a slit is prevented. We found out that we could suppress.

The specific means for solving the said subject is as follows.

The carboxylic acid derivative which consists of at least 1 sort (s) chosen from the group which consists of a <1> phthalic acid compound, an isophthalic acid compound, the alkyldicarboxylic acid compound represented by following General formula (I), these salts, and an acid anhydride, and a metal system It is 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.

HOOC-R-COOH... (I)

(In General Formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

By setting it as such an abrasive | polishing agent, corrosion inhibitory property can be improved, maintaining the favorable grinding | polishing rate with respect to a cobalt layer.

At least one carboxylic acid derivative selected from the group consisting of a <2> phthalic acid compound, an isophthalic acid compound, an alkyldicarboxylic acid compound represented by the following general formula (I), and salts and acid anhydrides thereof, and a metal anticorrosive agent 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 in an abrasive at 50 ° C. of 10.0 nm / min or less.

HOOC-R-COOH... (I)

(In General Formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

By setting it as such an abrasive | polishing agent, corrosion inhibitory property can be improved, maintaining the favorable grinding | polishing rate with respect to a cobalt layer.

<3> The said metal anticorrosive is an abrasive | polishing agent as described in said <1> or <2> containing the compound which has a triazole skeleton.

Thereby, corrosiveness can be suppressed more effectively.

<4> It is an abrasive as described in any one of said <1>-<3> which further contains an oxidizing agent.

Thereby, when a to-be-polished film contains layers other than a cobalt layer, the polishing rate of layers other than a cobalt layer can be improved more.

<5> It is an abrasive | polishing agent in any one of said <1>-<4> which further contains an organic solvent.

Thereby, when the to-be-polished film contains layers other than a cobalt layer, since the wettability with respect to layers other than a cobalt layer improves, a polishing rate can be improved more.

<6> It is an abrasive as described in any one of said <1>-<5> which further contains a water-soluble polymer.

Thereby, the to-be-polished surface is protected and corrosion can be suppressed and defect generation, such as a scratch, can be reduced.

<7> The abrasive according to any one of the above <1> to <6>, which further contains abrasive grains.

Thereby, when a to-be-polished film contains layers other than a cobalt layer, the polishing rate of layers other than a cobalt layer can be improved more.

The to-be-polished film containing the cobalt element formed in the at least one surface of a <8> board | substrate is polished using the abrasive | polishing agent in any one of said <1>-<7>, and the excess part containing a cobalt element is removed. It is a grinding | polishing method of the board | substrate.

According to the grinding | polishing method of this invention, it becomes possible to grind | polish the to-be-polished film containing a cobalt element at high speed and suppressing excessive corrosion.

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

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross section which shows the wiring formation process in the conventional damascene process.
It is a schematic cross section which shows the wiring formation process in the damascene process using a cobalt layer.
It is sectional drawing which shows an example of the board | substrate after grinding | polishing by the grinding | polishing method of this invention.

In this specification, the term "process" is included in this term as long as the intended purpose of the process is achieved even when it is not distinguished from not only an independent process but other processes. In addition, the numerical range shown using "-" shows the range which includes the numerical value described before and after "-" as minimum value and the maximum value, respectively. In addition, content of each component in an abrasive | polishing agent means the total amount of the said some substance existing in an abrasive | polishing agent, unless there is particular notice, when there exist two or more substances corresponding to each component in an abrasive | polishing agent.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of the grinding | polishing agent (henceforth simply a "polishing agent") for grinding | polishing the layer containing the cobalt element of this invention, and a board | substrate grinding | polishing method is explained in full detail.

[abrasive]

The abrasive | polishing agent of this invention is a carboxylic acid derivative which consists of at least 1 sort (s) chosen from the group which consists of a phthalic acid compound, an isophthalic acid compound, the alkyldicarboxylic acid compound represented by following General formula (I), and these salts and anhydrides, It contains a metal anticorrosive agent and water, and pH is 4.0 or less.

HOOC-R-COOH... (I)

(In General Formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

<Carboxylic acid derivative>

The abrasive | polishing agent of this invention consists of a phthalic acid compound, an isophthalic acid compound, and the dicarboxylic acid compound represented by the said General formula (I) (henceforth these are also called a "specific dicarboxylic acid compound"), these salts, and an acid anhydride. Carboxylic acid derivatives (hereinafter also referred to as "specific carboxylic acid derivatives") which are at least one member selected from the group. The said specific carboxylic acid derivative can be used individually by 1 type or in mixture of 2 or more types. By selecting the specific carboxylic acid derivative among the carboxylic acid and the carboxylic acid derivative present in anhydrous, while maintaining a good polishing rate for the cobalt layer, the etching rate is controlled appropriately to suppress corrosion and to provide a good polishing surface. You can get it. Further, even under more stringent conditions (for example, 50 ° C.), the etching rate of the cobalt layer can be more effectively suppressed, and excellent corrosion inhibitory property can be achieved. The excellent corrosion inhibiting property includes that the cobalt layer is etched on the surface to be polished or slit is formed in the wiring layer effectively suppressed.

The reason why such an effect is obtained is not clear, but the present inventor infers as follows. That is, it is thought that the said specific carboxylic acid derivative has an effect which functions as a metal solubilizer and improves the polishing rate with respect to a cobalt layer, for example. At the same time, the specific carboxylic acid derivative has a function of inhibiting corrosion on the surface to be polished by controlling the etching rate to form a stable complex state by chelating two carboxyl groups with respect to cobalt atoms to form a cyclic structure. It is assumed to have also. In addition, the metal anticorrosive agent mentioned later may contribute to formation of this stable complex state.

The said specific carboxylic acid derivative is chosen from the group which consists of a specific dicarboxylic acid compound, its salt, and these acid anhydride from a viewpoint of the polishing rate with respect to a cobalt layer, controllability of an etching rate, and corrosion inhibitory property. In acidic compounds other than the said specific carboxylic acid derivative, both the favorable polishing rate with respect to a cobalt layer, and suppression of the suppression of the etching rate of a cobalt layer may be difficult. This is considered to be because formation of a stable complex state is important as mentioned above, and the steric structure of an acidic compound becomes an important factor. Moreover, even if it contains the said specific carboxylic acid derivative, when the other acidic compound is included, the etching rate of a cobalt layer may rise remarkably. This is considered to be because the etching effect of the cobalt layer by another acidic compound has priority over formation of the complex state as mentioned above.

The 1st aspect of the abrasive of this invention is the said carboxylic acid derivative chosen from the group which consists of a phthalic acid compound, an isophthalic acid compound, the dicarboxylic acid compound represented by the said general formula (I), these salts, and acid anhydrides. It consists of at least 1 type. However, the said carboxylic acid derivative is a dicarboxylic acid compound other than the phthalic acid compound, the isophthalic acid compound, and the dicarboxylic acid compound represented by the said general formula (I), and its salt in the range which does not impair the effect of this invention remarkably. And other carboxylic acid derivatives which are at least one member selected from the group consisting of the acid anhydrides. 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. "Substantially" here is a range in which the effect of this invention is not impaired remarkably, Specifically, it means that the content rate of the said other carboxylic acid derivative is 10 mass% or less with respect to a 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.

In the same viewpoint, the 2nd aspect of the abrasive of this invention is that the said carboxylic acid derivative consists of a phthalic acid compound, an isophthalic acid compound, the dicarboxylic acid compound represented by the said general formula (I), these salts, and acid anhydrides. It contains at least 1 sort (s) chosen from the group, and the etching rate with respect to cobalt in 50 degreeC abrasive is 10.0 nm / min or less. In a 2nd aspect, the said carboxylic acid derivative consists of a phthalic acid compound, an isophthalic acid compound, and dicarboxylic acid compounds other than the dicarboxylic acid compound represented by the said General formula (I), its salt, and its acid anhydride. Although it may contain the other carboxylic acid derivative which is at least 1 sort (s) chosen, it is necessary for the etching rate with respect to cobalt in the 50 degreeC abrasive not to exceed 10.0 nm / min. About the preferable range of the content rate of said other carboxylic acid derivative, it is the same as that of the said 1st aspect.

The etching rate with respect to cobalt in a 50 degreeC abrasive can be measured as follows. That is, a 20 mm square chip (evaluation chip) having a 0.3 μm thick cobalt layer formed on a silicon substrate was prepared, and the evaluation chip was placed in a beaker containing 50 g of an abrasive, and then placed in a thermostat at 50 ° C. for 1 minute. It can be calculated | required as (membrane thickness of the cobalt layer before immersion-film thickness of the cobalt layer after immersion) / 1 minute [nm / min] by immersing and measuring the film thickness of the cobalt layer before and behind immersion.

In the 2nd aspect of the abrasive of this invention, although the said etching rate is 10.0 nm / min or less, 9.0 nm / min or less is preferable and 8.0 nm / min or less is more preferable from a viewpoint of further improving corrosion inhibitory property. .

Moreover, also in the 1st aspect of the abrasive of this invention, it is preferable that the said etching rate is 10.0 nm / min or less, more preferably 9.0 nm / min or less, and 8.0 nm / min from a viewpoint of improving corrosion inhibition property more The following is more preferable.

Among the specific dicarboxylic acid compounds, the phthalic acid compound includes at least one of phthalic acid derivatives having one or more substituents on phthalic acid (benzene-1,2-dicarboxylic acid) and the benzene ring.

A methyl group, an amino group, a nitro group etc. are mentioned as said substituent. Especially, 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 compound include alkyl phthalic acid such as phthalic acid, 3-methylphthalic acid and 4-methylphthalic acid; aminophthalic acid such as 3-aminophthalic acid and 4-aminophthalic acid; 3-nitrophthalic acid and 4-nitrophthalic acid. Nitrophthalic acid; and the like. Especially, the phthalic acid compound (nitrophthalic acid) which has a nitro group as a substituent is preferable, at least one of 3-nitrophthalic acid and 4-nitrophthalic acid is more preferable, and 3-nitrophthalic acid is especially preferable. The said phthalic acid compound may be used as an acid anhydride, and may be used as a salt.

The isophthalic acid compound includes at least one of isophthalic acid (benzene-1,3-dicarboxylic acid) and an isophthalic acid derivative having one or more substituents on the benzene ring. As said substituent, a nitro group, a methyl group, an amino group, a hydroxyl group, etc. are mentioned. Especially, 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 said general formula (I) should just be an alkyldicarboxylic acid compound which has a C4-C10 alkylene group. In addition, the said carbon number is carbon number of an alkylene group, and the carbon atom contained in a carboxylic acid group is not counted as said carbon number. The alkylene group may be any of cyclic, linear and branched chains. Especially, a linear thing is preferable. It is preferable that it is 4-8, and, as for carbon number, from a viewpoint of the polishing rate with respect to a cobalt layer, controllability of an etching rate, and corrosion suppression, it is more preferable that it is 4-6.

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

It is preferable that content of the said carboxylic acid derivative is 0.001 mass%-10 mass% on the basis of the gross mass of an abrasive | polishing agent. By adjusting content of the said carboxylic acid derivative to the said range, metals for wiring, such as copper which are layers other than the cobalt layer formed in the vicinity of a cobalt layer (for example, electroconductive material layer 5 shown to Fig.2 (a)), , A good polishing rate of 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. Moreover, as for content of the said dicarboxylic acid, 5.0 mass% or less is preferable from a viewpoint of the etching suppression effect and corrosion inhibitory property with respect to a cobalt layer, 3.0 mass% or less is more preferable, 1.0 mass% or less is further more preferable. , 0.7 mass% or less is very preferable, and 0.5 mass% or less is very preferable.

The said abrasive | polishing agent is represented by alkylphthalic acid, aminophthalic acid, nitrophthalic acid, isophthalic acid, 5-nitroisophthalic acid, and general formula (I) as a carboxylic acid derivative from a viewpoint of a grinding | polishing rate, and R is a C4-C8 linear chain. It is preferable to contain 0.01 mass% or more of the alkyldicarboxylic acid compound which is a type | mold alkylene group, and at least 1 sort (s) chosen from the group which consists of these salts and acid anhydrides.

Moreover, the said abrasive | polishing agent is represented by alkyl phthalic acid, aminophthalic acid, nitrophthalic acid, isophthalic acid, 5-nitroisophthalic acid, and general formula (I) as a carboxylic acid derivative from a viewpoint of suppressing the etching effect with respect to a cobalt layer. It is preferable to contain 5.0 mass% or less of at least 1 sort (s) chosen from the group which consists of an alkyldicarboxylic acid compound which is a C4-C8 linear alkylene group, and these salts and acid anhydrides.

<Metal anticorrosive agent>

There is no restriction | limiting in particular as a metal anticorrosive agent contained in the abrasive | polishing agent of this invention, Any conventionally well-known thing can be used as a compound which has anticorrosive effect with respect to a metal. 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 hexamethylenetetramine can be used. Can be. A "compound" is a generic term of the compound which has the skeleton here, For example, a triazole compound means the compound which has 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 and 1-hydride. Hydroxybenzotriazole, 1-dihydroxy propylbenzotriazole, 2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole, 4-carboxy-1H-benzotriazole, 4-carboxy-1H- Benzotriazole methyl ester (1H-benzotriazole-4-carboxylic acid methyl), 4-carboxy-1H-benzotriazole butyl ester (1H-benzotriazole-4-butyl carboxylate), 4-carboxy- 1H-benzotriazoleoctyl ester (1H-benzotriazole-4-octyl acid octyl), 5-hexylbenzotriazole, (1,2,3-benzotriazolyl-1-methyl) (1,2,4 -Triazolyl-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-1,2,3-triazole Rho [4,5-b] pyridine, 3-hydroxypyridine, 1,2,4-triazolo [1,5-a] pyrimidine, 1,3,4,6,7,8-hexahydro-2H -Pyrimid [1,2-a] pyrimidine, 2-methyl-5,7-diphenyl- [1,2,4] triazolo [1,5-a] pyrimidine, 2-methylsulfanyl-5 , 7-diphenyl- [1,2,4] triazolo [1,5-a] pyrimidine, 2-methylsulfanyl-5,7-diphenyl-4,7-dihydro- [1,2, 4] triazolo [1,5-a] pyrimidine and the like. In addition, when it has a triazole skeleton and another skeleton in 1 molecule, it shall classify as a triazole compound.

As a pyridine compound, for example, 8-hydroxyquinoline, prothionamide, 2-nitropyridin-3-ol, pyridoxamine, nicotinamide, iproniazide, isnicotinic acid, benso [f] quinoline, 2 , 5-pyridinedicarboxylic acid, 4-styrylpyridine, anabacin, 4-nitropyridine-1-oxide, pyridine-3-ethyl acetate, quinoline, 2-ethylpyridine, quinoline acid, arecoline, citrazinic acid And pyridine-3-methanol, 2-methyl-5-ethylpyridine, 2-fluoropyridine, pentafluoropyridine, 6-methylpyridin-3-ol, pyridine-2-ethyl acetate and the like.

Examples of the pyrazole compound include pyrazole, 1-allyl-3,5-dimethylpyrazole, 3,5-di (2-pyridyl) pyrazole, 3,5-diisopropylpyrazole, 3 , 5-dimethyl-1-hydroxymethylpyrazole, 3,5-dimethyl-1-phenylpyrazole, 3,5-dimethylpyrazole, 3-amino-5-hydroxypyrazole, 4-methylpyrazole, N-methylpyrazole, 3-aminopyrazole, 3-aminopyrazole, etc. are mentioned.

As a pyrimidine compound, pyrimidine, 1, 3- diphenyl- pyrimidine-2, 4, 6-trione, 1, 4, 5, 6- tetrahydropyrimidine, 2, 4, 5, 6- tetra Aminopyrimidine sulfate, 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-acetamidepyrimidine, 2-aminopyrimidine, 4- Aminopyrazolo [3,4-d] pyrimidine and the like.

Examples of the imidazole compound include 1,1'-carbonylbis-1H-imidazole, 1,1'-oxarylylimidazole, 1,2,4,5-tetramethylimidazole, 1, 2-dimethyl-5-nitroimidazole, 1,2-dimethylimidazole, 1- (3-aminopropyl) imidazole, 1-butylimidazole, 1-ethylimidazole, 1-methylimidazole And benzimidazole.

As a guanidine compound, for example, 1,1,3,3-tetramethylguanidine, 1,2,3-triphenylguanidine, 1,3-di-o-tolylguanidine, 1,3-diphenylguanidine, and the like Can be mentioned.

As a thiazole compound, 2-mercapto benzothiazole, 2, 4- dimethyl thiazole, etc. are mentioned, for example.

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

As a triazine compound, 3, 4- dihydro-3-hydroxy-4-oxo-1, 2, 4- triazine etc. are mentioned, for example.

The said metal anticorrosive can be used individually by 1 type or in mixture of 2 or more types. Since content of the said metal anticorrosive agent can obtain the favorable grinding | polishing rate with respect to the to-be-polished film containing a cobalt element, it is preferable that it is 0.001 mass%-10 mass% in the gross mass of an abrasive | polishing agent. From the same viewpoint, the content of the metal anticorrosive agent is more preferably 0.01% by mass or more, and even more preferably 0.02% by mass or more. Moreover, it is more preferable that it is 5.0 mass% or less, and, as for content of the said metal anticorrosive agent from a same viewpoint, it is still more preferable that it is 0.5 mass%.

In combination with the carboxylic acid derivative, the metal anticorrosive agent polishes the cobalt layer at an appropriate speed while significantly suppressing the etching rate of the cobalt layer even under stringent temperature conditions (for example, 50 ° C), It is possible to suppress the corrosion of the cobalt layer. This is considered to be because, for example, a metal anticorrosive agent functions as an excellent complex forming agent and a film protective agent in coexistence with the said specific dicarboxylic acid compound.

From such a viewpoint, at least 1 type chosen from the group which consists of a triazole compound, a pyridine compound, an imidazole compound, a tetrazole compound, a triazine compound, and hexamethylenetetramine is preferable among the said metal anticorrosive agent, 3H-1, 2,3-triazolo [4,5-b] pyridin-3-ol, 1-hydroxybenzotriazole, 1H-1,2,3-triazolo [4,5-b] pyridine, benzotriazole and the like Triazole compounds, 3-hydroxypyridine, benzimidazole, 5-amino-1H-tetrazole, 3,4-dihydro-3-hydroxy-4-oxo-1,2,4-triazine and hexa At least one selected from the group consisting of methylenetetramine is more preferred.

The ratio (carboxylic acid derivative / metal anticorrosive agent) of the carboxylic acid derivative and the metal anticorrosive agent in the polishing agent is 10/1 to 1/5 in a mass ratio from the viewpoint of controlling the etching rate and the polishing rate well. It is preferable that it is the range, It is more preferable that it is the range of 7/1-1/5, It is still more preferable that it is the range of 5/1-1/5, It is especially preferable that it is the range of 5/1-1/1 .

Moreover, the said abrasive | polishing agent is a group which consists of a carboxylic acid derivative, a triazole compound, a pyridine compound, an imidazole compound, a tetrazole compound, a triazine compound, and hexamethylenetetramine from a viewpoint of favorable control of an etching rate and a polishing rate. It is preferable that the ratio (carboxylic acid derivative / metal anticorrosive agent) of the at least 1 sort (s) of metal anticorrosive agent chosen from is 10/1-1/5,

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

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

<Oxidant>

It is preferable that the said abrasive further contains at least 1 sort (s) of oxidizing agent. By further containing an oxidizing agent, the polishing rate of layers other than a cobalt layer can be improved more. There is no restriction | limiting in particular in the said oxidizing agent, It can select suitably from the oxidizing agent normally used. Specifically, hydrogen peroxide, peroxosulfate, nitric acid, potassium periodate, hypochlorous acid, ozone water, etc. are mentioned, Especially, hydrogen peroxide is preferable. These metal oxidizing agents can be used individually by 1 type or in mixture of 2 or more types.

When an abrasive contains an oxidizing agent, it is preferable that content of a metal oxidizing agent shall be 0.01 mass%-50 mass% in the gross mass of an abrasive. From the viewpoint of preventing the oxidation of the metal from being insufficient and the polishing rate being lowered, the content is preferably 0.02% by mass or more, and more preferably 0.05% by mass or more. Moreover, since it can prevent that a roughness arises on a to-be-polished surface, 30 mass% or less is more preferable, and 15 mass% or less is still more preferable.

<Organic solvent>

The abrasive may further contain an organic solvent. By the addition of the organic solvent, the wettability of layers other than the cobalt layer formed in the vicinity of the cobalt layer can be improved, and the polishing rate can be further improved. Although there is no restriction | limiting in particular as said organic solvent, It is preferable that it is water solubility. Water solubility is defined as what melt | dissolves 0.1 g or more at 25 degreeC with respect to 100 g of water here.

Examples of the organic solvent include carbonate 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 and diethylene. Glycol solvents such as glycol, dipropylene glycol, triethylene glycol, tripropylene glycol; tetrahydrofuran, dioxane, dimethoxyethane, polyethylene oxide, ethylene glycol monomethyl acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl Ether solvents such as ether acetate; alcohol solvents such as methanol, ethanol, propanol, n-butanol, n-pentanol, n-hexanol, isopropanol and 3-methoxy-3-methyl-1-butanol; acetone, methylethyl Ketone solvents such as ketones; dimethylformamide, N-methylpyrrolidone, ethyl acetate, lact Ethyl, it can be given other organic solvent such as sulfolane.

Moreover, the organic solvent may be a derivative of the glycol solvent. 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 Propyl 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 Glycol monoether solvents such as glycol monobutyl ether and tripropylene glycol monobutyl ether; ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, triethylene glycol dimethyl ethyl ether, tripropylene glycol 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 Glycol dipropyl ether, diethylene glycol dipropyl ether, dipropylene glycol dipropyl 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.

Especially, it is preferable that it is at least 1 sort (s) chosen from a glycol solvent, a derivative of a glycol solvent, an alcohol solvent, and a carbonate ester solvent, and it is more preferable that it is at least 1 sort (s) chosen from an alcohol solvent. These organic solvents can be used individually by 1 type or in mixture of 2 or more types.

When an abrasive contains an organic solvent, it is preferable that content of an organic solvent is 0.1 mass%-95 mass% in the gross mass of an abrasive. 0.2 mass% or more is more preferable, and, as for content of the said organic solvent, the wettability with respect to the board | substrate becomes low, 0.5 mass% or more is more preferable. Moreover, from the point which facilitates preparation, use, wastewater treatment, etc. of an abrasive | polishing agent, 50 mass% or less is more preferable, and 10 mass% or less is still more preferable.

<Water-soluble polymer>

It is preferable that the said abrasive contains at least 1 type of water-soluble polymer. Thereby, suppression of a corrosion effect, protection of a film surface, reduction of defect generation, etc. can be achieved more effectively. Water solubility is defined as what melt | dissolves 0.1 g or more with respect to 100 g of water in 25 degreeC here.

As said water-soluble polymer, the water-soluble polymer etc. which have a carboxylic acid group or a carboxylate group are mentioned. As such a water-soluble polymer, the homopolymer of the monomer which has carboxylic acid groups, such as acrylic acid, methacrylic acid, and maleic acid; The homopolymer etc. whose part of the carboxylic acid group of the said polymer became carboxylic acid groups, such as an ammonium salt, etc. are mentioned. have. Moreover, the copolymer of derivatives, such as the monomer which has a carboxylic acid group, the monomer which has a carboxylate group, and the alkyl ester of carboxylic acid, is also preferable. Specifically as a water-soluble polymer, the polymer (henceforth "ammonium polyacrylate salt") etc. which polyacrylic acid and at least one part of the carboxylic acid group of polyacrylic acid substituted by the carboxylate ammonium salt group are mentioned.

Moreover, as other water-soluble polymers other than the above, For example, polysaccharides, such as alginic acid, pectic acid, carboxymethyl cellulose, agar, cyan, pullulan; polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polyamide Polycarboxylic acids and salts thereof such as acids, ammonium polyamic acid salts, sodium polyamic acid salts, and polyglyoxylic acids; vinyl-based polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrolein; and the like.

In the case where 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 viewpoint of avoiding contamination by the alkali metal, alkaline earth metal, halide or the like. However, the case where the board | substrate which is a grinding | polishing object is a glass substrate etc. is made an exception.

Among the above-mentioned water-soluble polymers, the group consisting of a water-soluble polymer having a carboxylic acid group or a carboxylate group, pectic acid, agar, polymalic acid, polyacrylamide, polyvinyl alcohol, and polyvinylpyrrolidone (to form esters and salts) If possible, water-soluble polymers selected from these are preferred. Water-soluble polymers (including esters and salts) having a carboxylic acid group or a carboxylate group are more preferred, and polyacrylic acid (including salts). More preferred, and ammonium polyacrylate salt is particularly preferred. These can be used individually by 1 type or in mixture of 2 or more types.

500-1,000,000 are preferable, as for the weight average molecular weight of a water-soluble polymer, 1,000-500,000 are more preferable, 2,000-200,000 are more preferable, 5,000-150,000 are especially preferable.

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

(Condition)

Sample: 10 μl

Standard polyacrylic acid: Hitachi Kasei Techno Service Co., Ltd. product name: PMAA-32

Detector: Hitachi, Ltd. production, RI-monitor, brand name "L-3000"

Integrator: Hitachi, Ltd. production, GPC integrator, brand name "D-2200"

Pump: Hitachi, Ltd. production, brand name "L-6000"

Degassing apparatus: Showa Denko manufacture, brand name "Shodex DEGAS"

Column: Hitachi Kasei Kogyo Co., Ltd. product name "GL-R440", "GL-R430", "GL-R420" are connected in this order, and used

Eluent: tetrahydrofuran (THF)

Measurement temperature: 23 degrees Celsius

Flow rate: 1.75 ml / min

Measurement time: 45 minutes

When an abrasive contains a water-soluble polymer, it is preferable that content of a water-soluble polymer is 0.001 mass%-10 mass% in the gross mass of an abrasive. 0.001 mass% or more is preferable, 0.01 mass% or more is more preferable, 0.02 mass% or more is more preferable at the point which can ensure favorable corrosion inhibitory property. Moreover, from the point which can maintain a sufficient grinding | polishing rate, it is preferable that it is 10 mass% or less, It is more preferable that it is 5.0 mass% or less, It is further more preferable that it is 1.0 mass% or less.

<Grip>

It is preferable that the said abrasive contains at least 1 type of abrasive grains. By including abrasive grains, the polishing rate of layers other than the cobalt layer formed in the vicinity of the cobalt layer can be improved.

As main abrasive grains, inorganic abrasive grains, such as silica, alumina, zirconia, ceria, titania, germania, silicon carbide, organic abrasive grains, such as polystyrene, polyacryl, polyvinyl chloride, etc. are mentioned, for example. Among these, inorganic abrasive particles selected from the group consisting of silica, alumina, zirconia, ceria, titania, and germania are preferred, and inorganic abrasive particles selected from the group consisting of silica and alumina are more preferable.

Among the inorganic abrasive grains selected from the group consisting of silica and alumina, colloidal silica or colloidal alumina is preferable because the dispersion stability in the abrasive is good and the number of scratches (scratches) generated by CMP is small. And colloidal silica are more preferable. These abrasive grains can be used individually by 1 type or in mixture of 2 or more types.

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

The average particle diameter of an abrasive grain is the value measured with the optical-diffraction scattering type particle size distribution meter (for example, brand name: COULTER N4SD by COULTER Electronics). The measurement conditions of Coulter are measurement temperature 20 degreeC, solvent refractive index 1.333 (corresponding to water), particle refractive index Unknown (setting), solvent viscosity 1.005 mPa * s (corresponding to water), Run Time 200 sec, laser incidence angle 90 °, Intensity (corresponding to scattering intensity and turbidity) falls within the range of 5E + 04 to 4E + 05, and is measured by diluting with water if higher than 4E + 05.

When an abrasive contains abrasive grains, 1.0 mass% or more is preferable in the gross mass of an abrasive | polishing agent, 3.0 mass% or more is more preferable, 3.0 mass%-5.0 mass% are more preferable. By setting content of the said abrasive grain in the said range, favorable grinding | polishing rate can be obtained.

<Water>

The water used in the present invention is not particularly limited, but pure water can be preferably used. Water should just be mix | blended as remainder of the structural material of the above-mentioned abrasive, and content does not have a restriction | limiting in particular.

<Others>

As another component which can be added to the said abrasive, coloring agents, such as surfactant, dyes, such as Victoria Pure Blue, and pigments, such as phthalocyanine green, are mentioned, for example.

PH of the said abrasive is 4.0 or less. When pH exceeds 4.0, there exists a possibility that the grinding | polishing rate of the conductive material layer and cobalt layer which consist of a wiring metal may fall. On the other hand, since corrosion of a metal for wiring is suppressed gradually and the handling difficulty by strong acidity can also be solved, it is preferable that the said pH is 1.0 or more, and it is more preferable that it is 2.0 or more.

pH can be adjusted with the addition amount of an acidic compound. Moreover, it can also adjust by addition of alkaline compounds, such as ammonia, sodium hydroxide, and 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 solution (phthalate pH buffer pH: 4.21 (25 ° C.), neutral phosphate pH buffer pH 6.86 (25 ° C.), borate pH buffer pH: 9.04 (25 ° C.), the electrode was polished. It can put into and, and after 3 minutes or more, the value after stabilization can be measured.

The said abrasive | polishing agent can be stored as an abrasive | polishing agent (stock solution) which contains a carboxylic acid derivative, a metal anticorrosive agent, and water, and you may use it, mix | blending this abrasive | polishing agent, another structural material, and water suitably at the time of grinding | polishing. Alternatively, the carboxylic acid derivative, the metal anticorrosive agent and water may be stored and used in an abrasive state in which other constituent materials are appropriately blended.

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

That is, the other aspect of this invention is carboxylic acid which consists of a phthalic acid compound, an isophthalic acid compound, the alkyldicarboxylic acid compound represented by following General formula (I), and at least 1 sort (s) chosen from the group which consists of these salts and acid anhydrides. It is use for grinding | polishing the layer containing a derivative, a metal anticorrosive agent, and water, and containing the cobalt element of the abrasive whose pH is 4 or less.

HOOC-R-COOH... (I)

(In General Formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

Moreover, the other aspect of this invention is at least 1 sort (s) of carboxylic acid chosen from the group which consists of a phthalic acid compound, an isophthalic acid compound, the alkyldicarboxylic acid compound represented by following General formula (I), and these salts and acid anhydrides. Use in polishing a layer containing a cobalt element of an abrasive containing a derivative, a metal anticorrosive, and water, 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. to be.

HOOC-R-COOH... (I)

(In General Formula (I), R represents an alkylene group having 4 to 10 carbon atoms.)

[Glass Polishing Method]

The grinding | polishing method of the board | substrate of this invention is a grinding | polishing method which removes the extra part containing a cobalt element by grind | polishing the to-be-polished film containing the cobalt element formed in the at least one surface of a board | substrate using the above-mentioned abrasive | polishing agent. More specifically, the surface of the substrate on the surface side on which the surface to be polished is formed is supplied while the above-described abrasive is supplied between the polishing film containing the cobalt element formed on at least one surface of the substrate and the polishing cloth on the polishing surface. It is a grinding | polishing method which removes at least one part of a to-be-polished film by moving the board | substrate and a polishing plate relatively in the state pushed in.

Hereinafter, a series of steps of wiring layer formation in a semiconductor device using the polishing method of the substrate of the present invention will be described with reference to FIG. 2. However, the use of the abrasive | polishing agent of this invention is not limited to the following process.

As shown in Fig. 2 (a), the substrate 10 before polishing includes an insulator (2) having a recess of a predetermined pattern on the silicon substrate (1), and an insulator (not shown) along the unevenness of the surface of the insulator (2). The barrier metal layer 3 which coat | covers 2) and the cobalt layer 4 which coat | covers the barrier metal layer 3 are provided, and the conductive material layer 5 is formed on the cobalt layer 4.

As the insulator 2, a silicone type insulator, an organic polymer type insulator, etc. are mentioned. Examples of the silicon insulator include silica insulators such as silicon dioxide, fluorosilicate glass, trimethylsilane and dimethoxydimethylsilane as starting materials, silica insulators such as organosilicate glass, silicon oxynitride and hydrogenated sesquioxane, silicon carbide and Silicon nitride, and the like. Moreover, as an organic polymer type insulator, a wholly aromatic low dielectric constant insulator is mentioned. Among 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. As an example of the insulator 2, the insulator in an LSI manufacturing process, especially a multilayer wiring formation process, etc. are mentioned.

The barrier metal layer 3 is formed to prevent diffusion of the conductive material into the insulator 2 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 alloys, titanium compounds such as titanium, titanium nitride, and titanium alloys, tungsten compounds such as tungsten, tungsten nitride, and tungsten alloys, and ruthenium. Ruthenium compounds, such as these, etc. are mentioned. The barrier metal layer 3 may be a single layer structure composed of one of these, or may be a laminated structure composed of two or more kinds. The barrier metal layer 3 is formed into a film by vapor deposition, CVD (chemical vapor deposition), or the like. In addition, only the cobalt layer 4 may be formed as the barrier metal layer 3.

Examples of cobalt used for the cobalt layer 4 include cobalt, cobalt alloys, oxides of cobalt, and oxides of cobalt alloys. 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 metals such as copper, copper alloys, oxides of copper, and oxides of copper alloys such as copper, tungsten metals such as tungsten and tungsten alloys, silver, and gold. Noble metals and the like. Especially, the metal which has copper as a main component, 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, plating method or the like.

The thickness of the insulator 2 is about 0.01 μm to 2.0 μm, the thickness of the barrier metal layer 3 is about 0.01 μm to 2.5 μm, the thickness of the cobalt layer 4 is about 0.01 μm to 2.5 μm, and the conductive material layer As for the thickness of (5), about 0.01 micrometer-about 2.5 micrometer are preferable.

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, polishing is performed by CMP using an abrasive for a conductive material having a sufficiently large polishing rate ratio of the conductive material layer 5 / cobalt layer 4. Thereby, the cobalt layer 4 of the convex part on a board | substrate is exposed to the surface, and the board | substrate 20 which has a conductor pattern in which the conductive material layer 5 was left in the recessed part is obtained. As an abrasive | polishing agent for the said electroconductive substance with a big polishing rate ratio of the conductive material layer 5 / cobalt layer 4, the abrasive | polishing agent of Unexamined-Japanese-Patent No. 337464 can be used, for example. In the first polishing step, a part of the cobalt layer 4 of the convex portion may be polished together with the conductive material layer 5.

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

In the second polishing step, the polishing platen and the substrate 20 are relatively moved while supplying the abrasive of the present invention between the polishing cloth and the substrate while the substrate 20 is pressed on the polishing cloth of the polishing platen. The cobalt layer 4 exposed by the first polishing step is polished.

As the apparatus for polishing, a general polishing apparatus having a polishing plate attached to a holder holding a substrate to be polished, a motor capable of changing the rotation speed, and the like, and affixing a polishing cloth can be used. As the polishing cloth, a general nonwoven fabric, expanded polyurethane, porous fluororesin, or the like can be used, and there is no particular limitation.

The polishing conditions are not particularly limited, but the rotation speed of the polishing platen is preferably low rotation of 200 rpm or less so that the substrate does not protrude. It is preferable that the pressurization pressure with respect to the polishing cloth of the board | substrate which has a to-be-polished film is 1 kPa-100 kPa, and in order to satisfy the polishing surface uniformity of a polishing rate, and the flatness of a pattern, it is more preferable that it is 5 kPa-50 kPa. desirable.

During polishing, the abrasive of the present invention is continuously supplied by a pump or the like between the polishing cloth and the polishing film. Although this supply amount is not limited, it is preferable that the surface of the polishing cloth is always covered with an abrasive. It is preferable to dry the board | substrate after completion | finish of grinding | polishing after wash | cleaning well in flowing water, after dropping the water droplet which adhered on the board | substrate using spin-drying etc.

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

All the insulators 2 under the barrier metal layer 3 of the convex portion are exposed, and the conductive material layer 5 serving as the wiring layer is left in the concave portion, and the barrier metal layer 3 and the cobalt layer ( Polishing is terminated when the substrate 30 having the desired pattern in which the cross section of 4) is exposed is obtained.

In order to ensure more excellent flatness at the end of polishing, as shown in FIG. 3, in addition, as shown in FIG. 3, when the time until the desired pattern is obtained in the second polishing step is 100 seconds, 50 seconds of additional polishing may be referred to as 50% over polishing. In the case of overpolishing, part of the insulator 2 is also removed by polishing.

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

The abrasive of the present invention can be used not only for polishing the metal film formed on the semiconductor substrate as described above but also for polishing a substrate such as a magnetic head.

Example

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

<Evaluation of etching amount with respect to cobalt>

[Examples and Comparative Examples]

(Polishing agent manufacturing method)

In the container, the amounts of the metal anticorrosive agent and the carboxylic acid derivative shown in Table 1 and Table 2 were respectively added so as to be the compounding amounts shown in Table 1 as the final abrasive, and as the water-soluble polymer, ammonium polyacrylate salt (Hitachi Chemical Techno Service Co., Molecular Weight) 8000) was added as an amount of 0.02% by mass as the final abrasive, and 3-methoxy-3-methyl-1-butanol as an amount of 1.4% by mass as the final abrasive was added as an organic solvent, followed by stirring with ultrapure water. Mixed to dissolve all components.

Next, colloidal silica (manufactured by Fuso Chemical Industry Co., Ltd., particle size 60 nm) which is a silica particle was added as an abrasive grain in the quantity equivalent to 4.0 mass% in the total mass of the slurry prepared, and also the ultrapure water was obtained along with ultrapure water. . 30 mass% hydrogen peroxide water was added so that it might become 0.2 mass% in the total mass of the obtained slurry, and various abrasive | polishing agents were obtained.

The pH of each obtained abrasive is measured and shown in Table 1 and Table 2.

(Etching amount evaluation for cobalt)

The blanket substrate (a) which formed the cobalt layer of 300 nm in thickness by the CVD method on the 8-inch silicon substrate was prepared. The said blanket substrate (a) was cut into the 20 mm square chip, and the chip (b) for evaluation was prepared.

Each said chip for evaluation (b) was put into the beaker which put 50 g of said abrasives, respectively, and it immersed for 1 minute in 50 degreeC thermostat. After immersion, the chip for evaluation (b) was taken out and sufficiently washed with pure water, and then nitrogen gas was blown out to dry the moisture on the chip. The resistance of the chip for evaluation (b) after drying was measured by the resistivity meter, and it converted into the film thickness of the cobalt layer after immersion by following formula (1).

The calibration curve was obtained from the information of the resistance value corresponding to each film thickness of the blanket substrate (a), and the film thickness of the cobalt layer was calculated | required from following formula (1).

Film thickness of cobalt layer after immersion [nm]

= 104.5 × (resistance value [mΩ] / 1000 of evaluation chip b) ^-0.893 . (One)

And the etching rate of the cobalt layer was calculated | required by following formula (2) from the film thickness of the cobalt layer after obtained immersion, and the thickness of the cobalt layer before immersion.

Etching Rate of Cobalt Layer (Co-ER) [nm / min]

= (Film thickness of cobalt layer before immersion [nm]-film thickness of cobalt layer after immersion] / min. (2)

About each abrasive obtained above, the etching rate with respect to a cobalt layer was calculated | required. The results are shown in Table 1 and Table 2. In addition, in Table 1 and Table 2, "-" in the column of a carboxylic acid derivative and a metal anticorrosive agent shows that it is unmixed.

(Evaluation of Polishing Speed for Cobalt)

Moreover, the polishing rate (Co-RR) [nm / min] at the time of grinding | polishing the said blanket substrate (a) on the following conditions using each abrasive obtained above was evaluated. These results are shown together in Table 1 and Table 2. In addition, about some of the comparative examples, since the etching rate was too fast, evaluation of the polishing rate was abbreviate | omitted and was represented by "-".

<Polishing condition>

Abrasive cloth: IC 1000

Polishing pressure: 10.3 kPa (1.5 psi)

The rotation speed: Platen / head = 93/87 rpm

Supply amount of abrasive: 200 ml / min

Polishing time: 0.5 minutes

Polishing temperature: 50 degrees Celsius

As is apparent from Tables 1 and 2, in Examples 1 to 13, by simultaneously containing a specific dicarboxylic acid and a metal anticorrosive agent, the etching rate of cobalt is remarkably suppressed even under a condition of 50 ° C, and a cobalt layer is appropriately It can be seen that it can be polished at a speed. In this regard, in the abrasive of the present invention containing the carboxylic acid derivative, it is suggested that the specific dicarboxylic acid compound has a function as a complex forming agent and an anticorrosive agent. That is, according to the abrasive of the present invention, when the layer containing the cobalt element is polished, at a good polishing rate, the layer containing the cobalt element is effectively suppressed from excessively etching or causing slits due to corrosion. It is suggested that it can be polished.

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

Claims (8)

A carboxylic acid derivative comprising at least one 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 acid anhydrides thereof, a metal anticorrosive agent, An abrasive for polishing a layer containing cobalt element containing water and having a pH of 4.0 or less.
HOOC-R-COOH... (I)
(In General Formula (I), R represents an alkylene group having 4 to 10 carbon atoms.) At least one carboxylic acid derivative 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 acid anhydrides thereof, a metal anticorrosive agent, water A polishing agent for polishing a layer containing cobalt element, wherein the layer contains cobalt element 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.
HOOC-R-COOH... (I)
(In General Formula (I), R represents an alkylene group having 4 to 10 carbon atoms.) 3. The method according to claim 1 or 2,
The metal anticorrosive is an abrasive containing a compound having a triazole skeleton. The method according to any one of claims 1 to 3,
An abrasive further containing an oxidizing agent. The method according to any one of claims 1 to 4,
Further, an abrasive containing an organic solvent. 6. The method according to any one of claims 1 to 5,
An abrasive further containing a water-soluble polymer. 7. The method according to any one of claims 1 to 6,
Further abrasives containing 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 1-7, and the excess part containing a cobalt element is removed. Polishing method.

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