WO2018159530A1

WO2018159530A1 - Polishing solution, method for producing polishing solution, polishing solution stock solution, polishing solution stock solution containing body, and chemical mechanical polishing method

Info

Publication number: WO2018159530A1
Application number: PCT/JP2018/006964
Authority: WO
Inventors: 上村　哲也
Original assignee: 富士フイルム株式会社
Priority date: 2017-02-28
Filing date: 2018-02-26
Publication date: 2018-09-07
Also published as: KR20210104162A; CN110325614B; KR102405560B1; TW201835287A; JPWO2018159530A1; JP6890656B2; CN110325614A; KR20190109450A; TWI769219B

Abstract

One objective of the present invention is to provide a polishing solution which is not likely to cause dishing and defects on a polished surface when applied to CMP of an object to be polished, said object containing a cobalt-containing layer. Another objective of the present invention is to provide a method for producing a polishing solution, a polishing solution stock solution, a polishing solution stock solution containing body, and a chemical mechanical polishing method. A polishing solution according to the present invention is a polishing solution for chemical mechanical polishing, which contains a colloidal silica having a degree of association of 1-3, an organic acid, an azole compound and hydrogen peroxide. If this polishing solution is in contact with a cobalt substrate for 24 hours, a reaction layer that contains cobalt atoms and has a thickness of 0.5-20 nm is formed on the cobalt substrate.

Description

Polishing liquid, polishing liquid production method, polishing liquid stock solution, polishing liquid stock solution container, chemical mechanical polishing method

The present invention relates to a polishing liquid, a manufacturing method of the polishing liquid, a polishing liquid stock solution, a polishing liquid stock solution container, and a chemical mechanical polishing method.

In the manufacture of large-scale integrated circuits (LSIs), chemical mechanical polishing (CMP) is used for planarization of bare wafers, planarization of interlayer insulating films, formation of metal plugs, and formation of embedded wiring. ) Method is used.
As a polishing liquid used in CMP, for example, Patent Document 1 describes “a polishing liquid in which a reaction layer having a thickness of 100 nm or more is formed on a surface to be polished that has been in contact with the polishing liquid for 24 hours”. Has been.

JP 2004-123931 A

By the way, in recent years, cobalt has attracted attention as a wiring metal element replacing copper, in accordance with the demand for miniaturization of wiring.
The present inventor, referring to Patent Document 1, prepared a polishing liquid in which colloidal silica was blended as abrasive grains and studied its characteristics. It has been found that when this polishing liquid is applied, dishing tends to occur on the surface of the object to be polished. Further, it has been found that many defects due to surface roughness such as scratches and partial corrosion occur on the surface to be polished of the object to be polished.

Accordingly, an object of the present invention is to provide a polishing liquid in which dishing and defects are unlikely to occur on a surface to be polished when applied to CMP of an object to be polished including a cobalt-containing layer.
Another object of the present invention is to provide a method for producing a polishing liquid, a polishing liquid stock solution, a polishing liquid stock solution container, and a chemical mechanical polishing method.

As a result of intensive studies to achieve the above-mentioned problems, the inventors of the present invention solve the above-mentioned problems by a polishing liquid containing a predetermined component and capable of forming a reaction layer having a predetermined thickness when brought into contact with a cobalt substrate. The present invention has been completed.
That is, it has been found that the above-described problem can be achieved by the following configuration.

[1] Colloidal silica having an association degree of 1 to 3,
An organic acid,
An azole compound,
Hydrogen peroxide, and a polishing liquid used for chemical mechanical polishing of the cobalt-containing layer,
A polishing liquid in which a reaction layer having a thickness of 0.5 to 20 nm containing cobalt atoms is formed on the cobalt substrate when the polishing liquid and the cobalt substrate are brought into contact with each other for 24 hours.
[2] The content of the colloidal silica having the association degree of 1 to 3 is 0.01 to 1% by mass with respect to the total mass of the polishing liquid.
As the organic acid, an amino acid is contained,
As the azole compound, containing a benzotriazole compound and an azole compound different from the benzotriazole compound,
pH is 6.5 to 8.0,
When the polishing liquid and a barrier substrate made of any one metal selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn are contacted for 24 hours, The polishing liquid according to [1], wherein a reaction layer containing atoms and having a thickness of 0.01 to 5 nm is formed.
[3] The polishing liquid according to [2], wherein the polishing rate ratio R1 calculated from the following formula (3) is 250 to 2500.
Formula (3):
R1 = Cobalt substrate polishing rate with the polishing liquid / Barrier substrate polishing rate with the polishing liquid [4] The content of the colloidal silica having the association degree of 1 to 3 is 0.5 to 5 with respect to the total mass of the polishing liquid. Mass%,
As the azole compound, containing a benzotriazole compound and an azole compound different from the benzotriazole compound,
pH is 8.0-10.5,
When the polishing liquid is brought into contact with a barrier substrate made of any one metal selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn for 24 hours, atoms of the metal on the barrier substrate A reaction layer containing 0.01 to 5 nm in thickness is formed,
When the polishing liquid and an insulating film substrate made of any one of inorganic components selected from the group consisting of SiOx and SiOC are brought into contact for 24 hours, a thickness of 0.01 to 10 nm containing silicon atoms on the insulating film substrate The polishing liquid according to [1], wherein the reaction layer is formed.
[5] The organic acid is maleic acid, fumaric acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, It is at least one selected from the group consisting of merophanic acid, planitic acid, pyromellitic acid, mellitic acid, diphenic acid, citric acid, succinic acid, malic acid, malonic acid, and anthranilic acid,
The polishing liquid according to [4], wherein the content of the organic acid is 0.01 to 0.3% by mass with respect to the total mass of the polishing liquid.
[6] The polishing rate ratio R2 calculated from the following formula (4) is 0.01 to 2.0, and the polishing rate ratio R3 calculated from the following formula (5) is 0.05 to 2.0. , [4] or [5].
Formula (4):
R2 = Polishing speed of cobalt substrate with the above polishing liquid / Polishing speed of barrier substrate with the above polishing liquid Formula (5):
R3 = Polishing rate of cobalt substrate with the polishing solution / Polishing rate of insulating film substrate with the polishing solution [7] The hydrogen peroxide content is 0.001 to 5 mass%, [1] to [6 ] The polishing liquid in any one of.
[8] Furthermore, containing a metal impurity containing a metal atom,
The metal impurity contains at least one specific metal atom selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom,
When the specific metal atom is one selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom, the content of the specific metal atom is 0.01 to 100 mass ppb,
When the specific metal atoms are two or more selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms, the content of the specific metal atoms is 0 with respect to the total mass of the polishing liquid. The polishing liquid according to any one of [1] to [7], having a mass of 0.01 to 100 mass ppb. [9] The metal impurity contains metal particles containing at least one specific metal atom selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom,
When the specific metal atom contained in the metal particle is one selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom, the content of the specific metal atom contained in the metal particle is , And 0.01 to 50 mass ppb with respect to the total mass of the polishing liquid,
When the specific metal atom contained in the metal particle is two or more selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom, each of the specific metal atom contained in the metal particle The polishing liquid according to [8], wherein the content is 0.01 to 50 mass ppb with respect to the total mass of the polishing liquid.
[10] The polishing liquid according to [8] or [9], wherein the content ratio T1 calculated from the following formula (1) is 30,000 to 500,000.
Formula (1): T1 = content of hydrogen peroxide / total content of specific metal atoms selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms contained in the metal impurities [11] The compound represented by the general formula (1) described later contains 0.00001 to 1000 mass ppb of the compound represented by the general formula (1) with respect to the total mass of the polishing liquid. ] The polishing liquid according to any one of [10] to [10].
[12] The polishing according to any one of [1] to [11], further comprising an organic solvent, wherein the content of the organic solvent is 0.01 to 20% by mass relative to the total mass of the polishing liquid. liquid.
[13] Further, N-cocoyl sarcosinate, N-lauroyl sarcosinate, N-stearoyl sarcosinate, N-oleoyl sarcosinate, N-myristoyl sarcosinate, N-lauroyl glycine, N-myristoyl glycine N-palmitoyl glycine, N-lauroyl glutamic acid, N-cocoyl glutamic acid, potassium N-cocoyl glutamate, potassium N-lauroyl sarcosinate, N-lauroyl alaninate, N-myristoyl alaninate, and potassium N-cocoyl alaninate Any one of [1] to [12], comprising at least one compound selected from the group consisting of, wherein the total content of the compounds is 0.001 to 5% by mass relative to the total mass of the polishing liquid The polishing liquid as described.
[14] The azole compound contains a benzotriazole compound and any one or more selected from the group consisting of 1,2,4-triazole compounds, pyrazole compounds, and imidazole compounds. , [2] to [13].
[15] The average particle diameter ratio T2 before and after chemical mechanical polishing of the colloidal silica having the degree of association of 1 to 3 calculated from the following formula (2) is 1 to 5, [1] to [14 ] The polishing liquid in any one of.
Formula (2):
T2 = average particle diameter after chemical mechanical polishing / average particle diameter before chemical mechanical polishing [16] Colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, hydrogen peroxide, A method for producing a polishing liquid, comprising a dilution step of mixing a polishing liquid stock solution containing water with water to obtain the polishing liquid according to any one of [1] to [15].
[17] A colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, and hydrogen peroxide,
A polishing liquid stock solution used by diluting 2 to 50 times to prepare the polishing liquid according to any one of [1] to [15].
[18] The polishing liquid stock solution according to [17], wherein the pH change before and after dilution is 0.01 to less than 1 when diluted 2 to 50 times with water.
[19] A polishing liquid stock solution container comprising the polishing liquid stock solution according to [17] or [18] and a container made of a metal material containing no iron and containing the polishing liquid stock solution.
[20] While supplying the polishing liquid according to any one of [1] to [15] to the polishing pad attached to the polishing surface plate, the surface to be polished is brought into contact with the polishing pad, A chemical mechanical polishing method comprising a step of relatively moving a polishing object and the polishing pad to polish the surface to be polished to obtain a polished object.
[21] The chemical mechanical polishing method according to [20], wherein the object to be polished contains a cobalt-containing layer composed of at least one selected from the group consisting of cobalt and a cobalt alloy.

ADVANTAGE OF THE INVENTION According to this invention, when it applies to CMP of the to-be-polished body containing a cobalt containing layer, the polishing liquid which a dishing and a defect cannot generate | occur | produce on a to-be-polished surface can be provided.
Moreover, according to this invention, the manufacturing method of polishing liquid, polishing liquid stock solution, polishing liquid stock solution container, and the chemical mechanical polishing method can be provided.

It is sectional drawing which shows an example of a to-be-polished body. It is sectional drawing after performing 1st grinding | polishing with respect to a to-be-polished body. It is sectional drawing after performing 2nd grinding | polishing further with respect to a to-be-polished body.

Hereinafter, the present invention will be described in detail based on embodiments.
In addition, description of the component requirement described below is made | formed based on the embodiment of this invention, and this invention is not limited to such an embodiment.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Polishing liquid]
The polishing liquid of the present invention contains a colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, and hydrogen peroxide, and is used for chemical mechanical polishing of a cobalt-containing layer. When the polishing liquid and the cobalt substrate are brought into contact with each other for 24 hours, a reaction layer containing cobalt atoms and having a thickness of 0.5 to 20 nm (hereinafter also referred to as “reaction layer 1”) is formed on the cobalt substrate. .) Is a polishing liquid to be formed.

As one of the characteristics of the polishing liquid, when the polishing liquid and the cobalt substrate are brought into contact with each other for 24 hours, a reaction layer having a thickness of 0.5 to 20 nm containing cobalt atoms is formed on the cobalt substrate. A point is mentioned.

The thickness of the reaction layer is 0.5 nm or more, and preferably 2 nm or more. The thickness of the reaction layer is 20 nm or less, preferably 15 nm or less, and more preferably 10 nm or less. If the thickness of the reaction layer is less than 0.5 nm, it is difficult to obtain a sufficient polishing rate.
On the other hand, if the thickness of the reaction layer exceeds 20 nm, dishing tends to occur on the surface to be polished. The polishing liquid contains colloidal silica in order to improve the polishing rate. Colloidal silica comes into contact with the reaction layer during CMP and scrapes off the reaction layer. Therefore, when the polishing liquid produces a reaction layer of more than 20 nm under predetermined conditions, the surface to be polished is cut more than intended. It is estimated that dishing occurs.
When the degree of association of colloidal silica exceeds 3, defects are likely to occur on the surface to be polished, and dishing is also likely to occur. Colloidal silica having an association degree exceeding 3 is distorted as compared with colloidal silica having an association degree of 1 to 3, so that the contact area of the particles to the polished surface is small and close to point contact. For this reason, it is presumed that the surface roughness of the surface to be polished becomes rough and defects occur. Even when the reaction layer is thin, it has been confirmed that dishing is likely to occur on the surface to be polished if it is scraped with colloidal silica having an association degree exceeding 3.
Further, the organic acid and the azole compound contained in the polishing liquid contribute to the formation of the reaction layer, as well as metal ionized products (various metal ions including cobalt ions) scraped during the CMP process and the colloidal silica. It is presumed that this also contributes to the suppression of the binding. When the metal ionized product and the colloidal silica are combined, the particle size of the colloidal silica increases, dishing is more likely to occur on the surface to be polished, and defects are also likely to occur.

In the present specification, the reaction layer refers to a cobalt substrate (substrate made of cobalt) having a 10 mm × 10 mm surface to be polished, immersed in 10 mL of polishing liquid, and the cobalt substrate and polishing liquid are brought into contact at 25 ° C. for 24 hours. In this case, a reaction layer formed on the polished surface of the cobalt substrate is intended. When the cobalt substrate is immersed in the polishing liquid, a laminate in which the cobalt substrate and another substrate (for example, a silicon substrate) are stacked may be immersed in the polishing liquid.

The reaction layer contains cobalt atoms. The reaction layer may further contain oxygen atoms and the like, and it is preferable that the surface of the reaction layer contains a complex of components in the polishing liquid.
Here, the thickness of the reaction layer is determined according to the embodiment using a scanning electron microscope (SEM) after the contact between the polishing liquid and the cobalt substrate for 24 hours and the cross section of the contacted cobalt substrate. The thickness obtained by observation by the described method is intended.

[PH]
The pH of the polishing liquid is not particularly limited, but is usually 1.0 to 14.0.

As will be described later, the polishing liquid is suitably used for CMP performed for planarization of a buried wiring (cobalt wiring) or the like when manufacturing a semiconductor integrated circuit device.
For example, the polishing liquid is suitably used for CMP of an object to be polished having an insulating film layer, a barrier layer, and a cobalt-containing layer. The object to be polished is normally filled with an insulating film layer having a convex part and a concave part, a barrier layer covering the insulating film layer along the surface irregularities of the insulating film layer, and a concave part of the insulating film layer. A cobalt-containing layer made of at least one selected from the group consisting of cobalt and an alloy thereof covering the barrier layer. FIG. 1 shows an example of the object to be polished. The object to be polished 10 includes a substrate 12, an insulating film layer 14 having a recess disposed on the substrate 12, a barrier layer 16 disposed following the surface of the insulating film layer 14, and a recess in the insulating film layer 14. And a cobalt-containing layer 18 disposed so as to cover the barrier layer 16.
The object to be polished is usually polished in two stages. Specifically, as shown in FIG. 2, the first polishing for polishing the cobalt-containing layer 18 until the barrier layer 16 is exposed, and as shown in FIG. 3, the cobalt-containing layer 18 until the insulating film layer 14 is exposed. And 2nd grinding | polishing which grind | polishes the barrier layer 16 is implemented. The polishing liquid can be suitably applied to both the first polishing and the second polishing.

When the polishing liquid is applied to the first polishing, the pH of the polishing liquid is more preferably 6.5 to 8.0. When the pH is in the range of 6.5 to 8.0, when the polishing liquid is applied to CMP, the thickness of the reaction layer under a predetermined condition is easily adjusted to a desired range, so that dishing is less likely to occur. . Among them, the pH is preferably in the range of 6.8 to 7.8, and more preferably in the range of 6.8 to 7.2, in view of further suppressing the occurrence of dishing. In addition, polishing scratches that are one of the defects are strongly affected by the state of the surface to be polished and the type of organic acid contained in the polishing liquid. When the polishing liquid is applied to the first polishing, the polishing liquid preferably contains an amino acid as an organic acid, as will be described later, and the polishing liquid containing an amino acid has polishing scratches when the pH is 6.5 or more. It has been confirmed that the occurrence of defects can be further suppressed.

When the polishing liquid is applied to the second polishing, the pH of the polishing liquid is more preferably 8.0 to 10.5. When the pH is in the range of 8.0 to 10.5, when the polishing liquid is applied to CMP, the thickness of the reaction layer under a predetermined condition can be easily adjusted to a desired range, so that the occurrence of dishing is further suppressed. Is done. In addition, polishing scratches that are one of the defects are strongly affected by the state of the surface to be polished and the type of organic acid contained in the polishing liquid. When the polishing liquid is applied to the second polishing, the polishing liquid contains maleic acid, fumaric acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, phthalic acid, Selected from the group consisting of isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, merophanic acid, planitic acid, pyromellitic acid, mellitic acid, diphenic acid, citric acid, succinic acid, malic acid, malonic acid, and anthranilic acid It is preferable that the polishing liquid containing these organic acids can remarkably suppress polishing scratches when the pH is 8.0 or higher (preferably 8.2 or higher). It has been confirmed that the occurrence of is suppressed more. The pH is preferably in the range of 8.2 to 9.5, more preferably in the range of 8.7 to 9.5, in order to further suppress the occurrence of dishing and defects on the surface to be polished. More preferred.

[Colloidal silica]
The polishing liquid contains colloidal silica having an association degree of 1 to 3.
Colloidal silica has the effect of scraping off the reaction layer formed in the object to be polished. The polishing liquid contains colloidal silica, and the thickness of the reaction layer formed under predetermined conditions is estimated to be 0.5 to 20 nm, which is presumed to be one of the reasons for the effects of the present invention.

In the present specification, the degree of association is determined by the degree of association = average secondary particle diameter / average primary particle diameter.
The average primary particle diameter is a particle diameter (equivalent circle diameter) of 1000 primary particles arbitrarily selected from an image taken using a transmission electron microscope TEM2010 (pressurized voltage 200 kV) manufactured by JEOL Ltd. Measure and find the arithmetic average. The equivalent circle diameter is the diameter of the circle when assuming a true circle having the same projected area as the projected area of the particles at the time of observation.
The average secondary particle diameter corresponds to the average particle diameter (equivalent circle diameter) of the secondary particles in an aggregated state, and can be obtained by the same method as the above-described average primary particle diameter.
The degree of association of colloidal silica is 1 to 3, and 1.5 to 2.5 is preferable from the viewpoint that the polishing rate is more excellent. When the degree of association exceeds 3, the mechanical polishing force becomes excessive and dishing tends to occur. Further, since the surface to be polished becomes rough, defects are easily generated. On the other hand, when the degree of association is less than 1, it is difficult to obtain a desired polishing rate. The average primary particle diameter of the colloidal silica is not particularly limited, but is preferably 1 to 100 nm from the viewpoint that the polishing liquid has better dispersion stability.

Examples of commercially available colloidal silica having an association degree of 1 to 3 include PL2, PL3, PL3H, and PL3L (all trade names are manufactured by Fuso Chemical Industry Co., Ltd.).
Is mentioned.

The content of the colloidal silica having an association degree of 1 to 3 is not particularly limited and is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and preferably 10% by mass or less with respect to the total mass of the polishing liquid. 5 mass% or less is more preferable, 3 mass% or less is still more preferable, and 1 mass% or less is especially preferable.

When the polishing liquid is applied to the first polishing, the content of colloidal silica having an association degree of 1 to 3 is more preferably 0.01 to 1% by mass with respect to the total mass of the polishing liquid. When the content of the colloidal silica having an association degree of 1 to 3 is in the above range, dishing on the surface to be polished is less likely to occur, and an excellent polishing rate can be obtained. In particular, when the content of colloidal silica having an association degree of 1 to 3 is in the range of 0.01 to 0.15% by mass with respect to the total mass of the polishing liquid, the occurrence of dishing is further suppressed.

On the other hand, when the polishing liquid is applied to the second polishing, the content of colloidal silica having an association degree of 1 to 3 is more preferably 0.5 to 5% by mass with respect to the total mass of the polishing liquid.
When the content of the colloidal silica having an association degree of 1 to 3 is in the above range, dishing on the surface to be polished is less likely to occur, and an excellent polishing rate can be obtained. In particular, when the content of colloidal silica having an association degree of 1 to 3 is in the range of 0.5 to 3% by mass with respect to the total mass of the polishing liquid, the occurrence of dishing is further suppressed.

Incidentally, colloidal silica having an association degree of 1 to 3 may be used alone or in combination of two or more. When two or more kinds of colloidal silica having an association degree of 1 to 3 are used in combination, the total content is preferably within the above range.

The average particle diameter ratio T2 before and after chemical mechanical polishing (CMP) calculated from the following formula (2) of colloidal silica having an association degree of 1 to 3 in the polishing liquid is preferably 5 or less. When T2 is 5 or less, defects are less likely to occur on the surface to be polished. The lower limit of T2 is preferably 1 or more. T2 is more preferably 2.5 or less, and even more preferably 2 or less. Formula (2):
T2 = average particle diameter after chemical mechanical polishing / average particle diameter before chemical mechanical polishing

It is presumed that colloidal silica having an association degree of 1 to 3 is bonded to metal ionized products (various metal ions including cobalt ions) cut out during the CMP process, thereby increasing the average particle size.

〔hydrogen peroxide〕
The polishing liquid contains hydrogen peroxide as an oxidizing agent. The oxidizing agent has a function of oxidizing a metal to be polished existing on the surface to be polished of the object to be polished.

The content of hydrogen peroxide is not particularly limited, but is preferably 0.001 to 5% by mass with respect to the total mass of the polishing liquid.

When the polishing liquid is applied to the first polishing, the content of hydrogen peroxide in the polishing liquid is 0.001 with respect to the total mass of the polishing liquid in that dishing on the surface to be polished is less likely to occur. Is more preferably 2.5% by mass, and still more preferably 0.06-2% by mass.

On the other hand, when the polishing liquid is applied to the second polishing, the content of hydrogen peroxide in the polishing liquid is 0 in that dishing on the surface to be polished is less likely to occur with respect to the total mass of the polishing liquid. 0.001 to 3 mass% is more preferable, 0.1 to 1.2 mass% is still more preferable, and 0.6 to 1 mass% is particularly preferable.

[Organic acid]
The polishing liquid contains an organic acid. The organic acid has an effect of promoting oxidation of the metal, adjusting the pH of the polishing liquid, and acting as a buffer.
In this specification, an organic acid is a compound having one or more acidic groups in one molecule, and examples of the acidic group include a carboxy group, a sulfonic acid group, and a phosphoric acid group.
It does not restrict | limit especially as an organic acid, A well-known organic acid can be used.
Examples of the organic acid include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, and n-heptane. Acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, 2- Hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, merophanic acid, planitic acid, pyromellitic acid, melittic acid, diphenic acid, citrate Acid, succinic acid, malic acid, malonic acid, anthranilic acid, tartaric acid, lactic acid, hydroxyethyliminodiacetic acid, And iminodiacetic acid and salts thereof such as ammonium salts and alkali metal salts thereof; glycine, α-alanine, β-alanine, N-methylglycine, L-2-aminobutyric acid, L-norvaline, L-valine, L- Leucine or its derivatives, L-proline, L-ornithine, L-lysine, taurine, L-serine, L-threonine, L-allothreonine, L-homoserine, L-tyrosine, L-thyroxine, 4-hydroxy-L- Proline, L-cystine, L-methionine, L-ethionine, L-cystine or a derivative thereof, L-cystine acid, L-aspartic acid, L-glutamic acid, 4-aminobutyric acid, L-asparagine, L-glutamine, azaserine, L-arginine, L-canavanine, L-citrulline, δ-hydroxy-L-lysine, creatine, L- Nurenin, L- histidine or a derivative thereof, and amino acids L- tryptophan and the like; and the like.

The content of the organic acid is not particularly limited, but is preferably 0.01 to 30% by mass with respect to the total mass of the polishing liquid.
In addition, an organic acid may be used individually by 1 type, or may use 2 or more types together. When two or more organic acids are used in combination, the total content is preferably within the above range.

When applying the polishing liquid to the first polishing, it is preferable that the polishing liquid contains an amino acid as an organic acid in that dishing on the surface to be polished is less likely to occur and / or defects are less likely to occur. Among these, glycine, α-alanine, β-alanine, L-aspartic acid, or N-methylglycine is more preferable, glycine or N-methylglycine is more preferable, and glycine is particularly preferable.

When the polishing liquid is applied to the first polishing, the content of the organic acid in the polishing liquid is not particularly limited, and is preferably 0.1% by mass or more and 0.8% by mass or more with respect to the total mass of the polishing liquid. Is more preferable, 30 mass% or less is preferable, 15 mass% or less is more preferable, 8 mass% or less is still more preferable, and 4 mass% or less is especially preferable.
When the content of the organic acid is 0.8 to 4% by mass with respect to the total mass of the polishing liquid, dishing and defects on the surface to be polished are less likely to occur.
An organic acid may be used individually by 1 type, or may use 2 or more types together.
In addition, it is also preferable to use a combination of an amino acid and another organic acid (not containing an amino acid) in that dishing on the surface to be polished is less likely to occur and / or defects are less likely to occur. Examples of the organic acid include maleic acid, fumaric acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, Melofanoic acid, planitic acid, pyromellitic acid, mellitic acid, diphenic acid, citric acid, succinic acid, malic acid, malonic acid or anthranilic acid are preferred. In addition, when using combining an amino acid and another organic acid (an amino acid is not included), the content of other organic acids is preferably 30% by mass or less based on the total amount of organic acids. More preferred is mass%. In addition, it is preferable that the minimum is 1 mass% or more.
When two or more organic acids are used in combination, the total content is preferably within the above range.

On the other hand, when the polishing liquid is applied to the second polishing, the polishing liquid is organic acid such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid. 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, glutaric acid , Adipic acid, pimelic acid, maleic acid, fumaric acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, merophane Acid, planitic acid, pyromellitic acid, mellitic acid, diphenic acid, citric acid, succinic acid, malic acid, malonic acid, anthranilic acid, liquor Acid, lactic acid, hydroxyethyliminodiacetic acid, and iminodiacetic acid, as well as to contain one kind or two or more species selected from the group consisting of salts such as their ammonium salts and alkali metal salts. Among them, maleic acid, fumaric acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid are less likely to cause dishing on the surface to be polished and / or less likely to cause defects. Phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, merophanic acid, planitic acid, pyromellitic acid, mellitic acid, diphenic acid, citric acid, succinic acid, malic acid, malonic acid, or anthranilic acid Preferably, maleic acid, 2-hydroxybenzoic acid, 4-hydroxybenzoic acid, phthalic acid, trimellitic acid, citric acid, succinic acid, malic acid, malonic acid, or anthranilic acid are more preferable, and maleic acid or citric acid is further Maleic acid is preferred and particularly preferred.
In addition, when two or more organic acids are used in combination, dishing on the surface to be polished is less likely to occur and / or defects are less likely to occur. A combination with at least one selected from the group consisting of acids, succinic acid, malic acid, malonic acid, phthalic acid, 4-hydroxybenzoic acid, 2-hydroxybenzoic acid, anthranilic acid, and trimellitic acid is preferable. , Citric acid, malonic acid, 4-hydroxybenzoic acid, 2-hydroxybenzoic acid, anthranilic acid, and a combination of at least one selected from the group consisting of trimellitic acid are more preferable. At least one selected from the group consisting of hydroxybenzoic acid, 2-hydroxybenzoic acid, anthranilic acid, and trimellitic acid Combination of more preferable.

When the polishing liquid is applied to the second polishing, the content of the organic acid in the polishing liquid is not particularly limited, and is preferably 0.01 to 30% by mass with respect to the total mass of the polishing liquid, and 0.01 to 12 % By mass is more preferable, 0.01 to 5% by mass is more preferable, and 0.01 to 0.3% by mass is still more preferable. In addition, when using 2 or more types of organic acids, it is preferable that total content is in the said range.

[Azole compounds]
The polishing liquid contains an azole compound. The azole compound has a function of forming a reaction layer on the metal surface of the polished surface. Moreover, it has the function to improve the oxidation action by the hydrogen peroxide mentioned later.
In the present specification, an azole compound means a compound containing a hetero five-membered ring containing one or more nitrogen atoms, and the number of nitrogen atoms is preferably 1 to 4. In addition, the azole compound may contain atoms other than nitrogen atoms as heteroatoms. Further, the azole compound may have a substituent on the hetero five-membered ring.

Examples of the azole compounds include pyrrole skeleton, imidazole skeleton, pyrazole skeleton, isothiazole skeleton, isoxazole skeleton, triazole skeleton, tetrazole skeleton, imidazole skeleton, thiazole skeleton, oxazole skeleton, isoxazole skeleton, thiadiazole skeleton, oxadi Examples thereof include compounds having an azole skeleton or a tetrazole skeleton.
The azole compound may be an azole compound having a polycyclic structure in which an aromatic hydrocarbon ring or an aromatic heterocyclic ring is further condensed to the skeleton. Examples of the azole compound containing the polycyclic structure include an indole skeleton, a purine skeleton, an indazole skeleton, a benzimidazole skeleton, a carbazole skeleton, a benzoxazole skeleton, a benzothiazole skeleton, a benzothiadiazole skeleton, or a naphthimidazole skeleton. And the like.

The substituent that the azole compound may contain is not particularly limited, and examples thereof include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched, or cyclic alkyl group). Yes, it may be a polycyclic alkyl group such as a bicycloalkyl group or may contain an active methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regarding the position of substitution), an acyl group, Alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group (Examples of the carbamoyl group having a substituent include N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoyl group) Carbamoyl group, thiocarbamoyl group, and N-sulfamoylcarbamo Carbazoyl group, carboxy group or a salt thereof, oxalyl group, oxamoyl group, cyano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (ethyleneoxy group or propyleneoxy group is repeated) Aryloxy group, heterocyclic oxy group, acyloxy group, carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, acylamino group, sulfonamido group, ureido group, thioureido group, N- Hydroxyureido group, imide group, carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonylureido group, N-acylureido N-acylsulfamoylamino group, hydroxyamino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (for example, pyridinio group, imidazolio group, quinolinio group, and isoquinolinio group), isocyano Group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group Or a salt thereof, a sulfamoyl group (the sulfamoyl group having a substituent includes, for example, N-acylsulfamoyl group and N-sulfonylsulfamoyl group) or a salt thereof, phosphino group, phosphinyl group, phosphinyl Oxy group, phosphinylamino group, silyl group, etc. It is.
Of these, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group is preferable.

Here, “active methine group” means a methine group substituted with two electron-attracting groups. The “electron withdrawing group” is, for example, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfamoyl group, a trifluoromethyl group, a cyano group, a nitro group, or A carbonimidoyl group is intended. Two electron-withdrawing groups may be bonded to each other to form a cyclic structure. The term “salt” is intended to include cations such as alkali metals, alkaline earth metals, and heavy metals; organic cations such as ammonium ions and phosphonium ions.

The azole compound has a triazole skeleton compound (triazole compound), a pyrazole compound, or an imidazole skeleton in that dishing on the polished surface is less likely to occur and / or defects are less likely to occur. A compound (imidazole compound) is preferable, and a compound having a triazole skeleton is more preferable.

Further, among compounds having a triazole skeleton, a compound having a benzotriazole skeleton (benzotriazole-based compound) or 1 in that dishing on a polished surface is less likely to occur and / or defects are less likely to occur. , 2,4-triazole skeleton compounds (1,2,4-triazole compounds) are preferred, and benzotriazole skeleton compounds are more preferred.
Examples of the compound having a benzotriazole skeleton include 5-methylbenzotriazole, 5-aminobenzotriazole, benzotriazole, and 5,6-dimethylbenzene · BR> tower] triazole.
Examples of the compound having a 1,2,4-triazole skeleton include 3-amino-1,2,4-triazole or 1,2,4-triazole.

The azole compounds may be used alone or in combination of two or more. However, benzoic compounds are less likely to cause dishing on the surface to be polished and / or less likely to cause defects. It is preferable to use a compound having a triazole skeleton in combination with a compound different from the benzotriazole-based compound (a compound not containing a benzotriazole skeleton). A compound containing a benzotriazole skeleton strongly coordinates to cobalt oxidized by hydrogen peroxide that is an oxidizing agent, and easily forms a reaction layer. On the other hand, even if it is an azole-type compound, the compound which does not contain a benzotriazole skeleton is coordinated comparatively weakly to the oxidized cobalt and tends to form a reaction layer. A reaction layer formed when a polishing liquid containing a benzotriazole-based compound and a compound different from benzotriazole is applied to CMP is a layer different from a layer formed from a benzotriazole-based compound and benzotriazole. It is estimated that it contains the layer formed by.
It is presumed that the layer formed of the benzotriazole-based compound strongly coordinated to the oxidized cobalt is dense and has an action of further suppressing the occurrence of dishing. On the other hand, a layer formed of a compound different from the benzotriazole-based compound weakly coordinated with oxidized cobalt is more easily removed, and as a result, it is presumed that an excellent polishing rate is easily obtained.
As a result, when the above action synergizes, when a polishing liquid containing a compound having a benzotriazole skeleton and a compound different from the benzotriazole-based compound (a compound not containing a benzotriazole skeleton) is applied to CMP, An excellent polishing rate can be obtained, and dishing is less likely to occur on the polished surface.

The compound containing no benzotriazole skeleton is not particularly limited, but has a 1,2,4-triazole skeleton in that dishing on the polished surface is less likely to occur and / or defects are less likely to occur. It is preferably at least one selected from the group consisting of a compound, a pyrazole-based compound, and a compound having an imidazole skeleton.

The content of the azole compound is not particularly limited, and is preferably 0.001 to 10% by mass with respect to the total mass of the polishing liquid. In addition, when using 2 or more types of azole type compounds, it is preferable that total content is in the said range.
When the polishing liquid is applied to the first polishing, the content of the azole compound is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and more preferably 2% by mass with respect to the total mass of the polishing liquid. The following is preferable, 1.3 mass% or less is more preferable, and 0.4 mass% or less is still more preferable.
When the content of the azole compound is 0.01% by mass or more, dishing is less likely to occur on the polished surface.
When the content of the azole compound is 1.3% by mass or less, dishing is less likely to occur on the surface to be polished, and the stability over time is excellent.
When the polishing liquid is applied to the first polishing, the polishing liquid contains two or more azole compounds (preferably, a compound having a benzotriazole skeleton and a compound different from the benzotriazole compounds). When the content is not particularly limited, the mass ratio of the content of the other azole compound to the azole compound having the smallest content in the polishing liquid is preferably 5 or more, more preferably 100 or more. More preferably, 1800 or less is preferable, 1300 or less is more preferable, and 400 or less is still more preferable. The content of the compound having a benzotriazole skeleton is preferably smaller than the content of a compound different from the benzotriazole-based compound.

When the polishing liquid is applied to the second polishing, the content of the azole compound is preferably 0.1% by mass or more, more preferably 0.12% by mass or more, and 6% by mass with respect to the total mass of the polishing liquid. The following is preferable, 3.5% by mass or less is more preferable, 0.8% by mass or less is further preferable, and 0.5% by mass or less is particularly preferable.
When the content of the azole compound is 0.12% by mass or more, dishing is less likely to occur on the polished surface.
When the content of the azole compound is 5% by mass or less, dishing is less likely to occur on the surface to be polished, and the stability over time is excellent.
On the other hand, when the polishing liquid is applied to the second polishing, the polishing liquid contains two or more azole compounds (preferably a compound having a benzotriazole skeleton and a compound different from the benzotriazole compound). )), The content of each is not particularly limited, and the mass ratio of the content of the other azole compound to the azole compound having the smallest content in the polishing liquid is 0.05 or more. Is preferably 0.5 or more, more preferably 50 or less, and even more preferably 10 or less. Further, the content of the compound having a benzotriazole skeleton is preferably larger than the content of a compound different from the benzotriazole-based compound.
Within the above range, dishing on the surface to be polished is less likely to occur and / or defects are less likely to occur.
The azole compound having the smallest content in the polishing liquid is intended to mean the least content of two or more azole compounds, and a plurality of azole compounds of two or more azole compounds. This may be the case for compounds.
In addition, three or more azole compounds may be used in combination. When three or more azole compounds are used in combination, the content of each azole compound is preferably within the above range.

[Optional ingredients]
The polishing liquid may contain components other than the above as optional components. Below, an arbitrary component is demonstrated.

<Abrasive>
The polishing liquid may further contain abrasive grains other than colloidal silica.

The abrasive grains are not particularly limited, and abrasive grains other than known colloidal silica can be used.
Examples of the abrasive grains include inorganic abrasive grains such as silica (precipitated silica other than colloidal silica or fumed silica), alumina, zirconia, ceria, titania, germania, and silicon carbide; polystyrene, polyacryl, polyvinyl chloride, etc. Organic abrasive grains.

<Organic solvent>
The polishing liquid preferably contains an organic solvent. It does not restrict | limit especially as an organic solvent, A well-known organic solvent can be used. Of these, water-soluble organic solvents are preferable.
Examples of the organic solvent include ketone solvents, ether solvents, alcohol solvents, glycol solvents, glycol ether solvents, amide solvents, and the like.
More specifically, for example, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, ethylene glycol, propylene glycol , And ethoxyethanol.
Among them, methyl ethyl ketone, tetrahydrofuran, dioxane, N-methylpyrrolidone, methanol, ethanol, propylene glycol, or ethylene glycol is preferable, methanol, ethanol, propylene glycol, or ethylene glycol is more preferable, and methanol, propylene glycol, or ethylene glycol. Is more preferable.

The content of the organic solvent is not particularly limited, but is preferably 0.01 to 20% by mass and more preferably 0.01 to 10% by mass with respect to the total mass of the polishing liquid in terms of more excellent effects of the present invention. 0.01 to 8% by mass is more preferable.
When the content of the organic solvent is in the range of 0.01 to 20% by mass, defects on the surface to be polished are less likely to occur.
In addition, the organic solvent may be used individually by 1 type, or may use 2 or more types together. When two or more organic solvents are used in combination, the total content is preferably within the above range.

<Surfactant and / or hydrophilic polymer>
The polishing liquid may contain a surfactant and / or a hydrophilic polymer. Surfactants and hydrophilic polymers (hereinafter also referred to as “hydrophilic polymers”) have a function of reducing the contact angle of the polishing liquid to the surface to be polished, and the polishing liquid tends to wet and spread on the surface to be polished. .
The surfactant is not particularly limited, and a known surfactant selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, and the like may be used. it can.
Examples of the anionic surfactant include carboxylic acid salts, sulfonic acid salts such as alkylbenzene sulfonic acids, sulfuric acid ester salts, and phosphoric acid ester salts.
Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium chloride salts, benzethonium chloride, pyridinium salts, and imidazolinium salts.
Examples of amphoteric surfactants include carboxybetaine type, aminocarboxylate, imidazolinium betaine, lecithin, and alkylamine oxide.
Examples of the nonionic surfactant include ether type, ether ester type, ester type, nitrogen-containing type, glycol type, and fluorine type surfactant.
Examples of hydrophilic polymers include polyglycols such as polyethylene glycol, alkyl ethers of polyglycols, polysaccharides such as polyvinyl alcohol, polyvinyl pyrrolidone, and alginic acid, carboxylic acid-containing polymers such as polymethacrylic acid, and polyacrylic acid, Examples include polyacrylamide, polymethacrylamide, and polyethyleneimine. Specific examples of such a hydrophilic polymer include water-soluble polymers described in JP2009-88243A, paragraphs 0042 to 0044, and JP2007-194261A, paragraph 0026.

In the above embodiment, the water-soluble polymer is preferably a water-soluble polymer selected from polyacrylamide, polymethacrylamide, polyethyleneimine, and polyvinylpyrrolidone. As polyacrylamide or polymethacrylamide, those having a hydroxyalkyl group on a nitrogen atom (for example, N- (2-hydroxyethyl) acrylamide polymer) or those having a substituent having a polyalkyleneoxy chain are preferred, and the weight average The molecular weight is more preferably 2000 to 50000. As the polyethyleneimine, those having a polyalkyleneoxy chain on the nitrogen atom are preferred, and those having a repeating unit represented by the following general formula are more preferred.

In the above formula, n represents a number of 2 to 200 (in the case of a mixture, the average number thereof).
Polyethyleneimine preferably has an HLB (Hydrophile-Lipophile Balance) value of 16 to 19.

The content of the surfactant or the hydrophilic polymer is not particularly limited, but is preferably 0.00001 to 2% by mass, more preferably 0.0001 to 1% by mass, and more preferably 0.0001 to 0% with respect to the total mass of the polishing liquid. More preferably, 5% by mass. When the content of the surfactant or the hydrophilic polymer is 0.0001 to 0.5% by mass, the colloidal silica having an association degree of 1 to 3 is formed after chemical mechanical polishing when the polishing liquid is applied to CMP. The average particle diameter hardly fluctuates and is excellent due to the effect of the present invention.
In addition, surfactant or a hydrophilic polymer may be used individually by 1 type, or may use 2 or more types together. Further, a surfactant and a hydrophilic polymer may be used in combination. When two or more kinds of surfactants, or two or more kinds of hydrophilic polymers, or a surfactant and a hydrophilic polymer are used in combination, the total content is preferably within the above range.

<PH adjusting agent and / or pH buffering agent>
The polishing liquid may further contain a pH adjuster and / or a pH buffer so as to have a predetermined pH. Examples of the pH adjusting agent and / or pH buffering agent include acid agents and / or alkali agents. The pH adjusting agent and the pH buffering agent are compounds different from the organic acid.
Although it does not restrict | limit especially as an acid agent, An inorganic acid is preferable. Examples of inorganic acids include sulfuric acid, nitric acid, boric acid, and phosphoric acid. Of these, nitric acid is more preferable.
The alkali agent is not particularly limited, but ammonium hydroxide and organic ammonium hydroxide; alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; carbonates such as sodium carbonate; trisodium phosphate And the like; borate and tetraborate; and the like.
The content of the pH adjusting agent and / or pH buffering agent is not particularly limited as long as it is an amount necessary to maintain the pH in a desired range, and is usually 0.0001 to 0 in the total mass of the polishing liquid. .1% by mass is preferable.

<Cobalt anticorrosive>
The above polishing liquid contains N-cocoyl sarcosinate, N-lauroyl sarcosinate, N-stearoyl sarcosinate, N-oleoyl sarcosinate, N-myristoyl sarcosinate, N-lauroyl as an anticorrosive for cobalt. Glycine, N-myristoyl glycine, N-palmitoyl glycine, N-lauroyl glutamic acid, N-cocoyl glutamic acid, N-cocoyl glutamic acid potassium, N-lauroyl sarcosinate potassium, N-lauroyl alaninate, N-myristoyl alaninate, and N -Preferably contains at least one compound selected from the group consisting of potassium cocoyl alaninate. The cobalt anticorrosive has a function of suppressing excessive corrosion of cobalt by forming a complex (composite compound) by coordinating with cobalt in the surface of the object to be polished.
The content of the cobalt anticorrosive is not particularly limited, but is preferably 0.001 to 5% by mass, more preferably 0.001 to 1% by mass, and 0.001 to 0.5% by mass with respect to the total mass of the polishing liquid. % Is more preferable. When the content of the cobalt anticorrosive is 0.001 to 5% by mass, dishing is less likely to occur on the surface to be polished, and defects are less likely to occur on the surface to be polished.
In addition, the said cobalt anticorrosive agent may be used individually by 1 type, or may use 2 or more types together. When using 2 or more types of the said cobalt anticorrosive agent together, it is preferable that total content is in the said range.

<Water>
The polishing liquid preferably contains water. The water contained in the polishing liquid is not particularly limited, but ion exchange water, pure water, or the like can be used.
The water content is not particularly limited, but is preferably 90 to 99% by mass based on the total mass of the polishing liquid.

<Metal impurities>
The polishing liquid may contain a metal impurity containing a metal atom.
In this specification, “metal impurities containing metal atoms” are metal ions and solids (metal simple substance, particulate metal-containing compounds, etc.). These are hereinafter collectively referred to as “metal particles”. .) Is intended as a metal impurity contained in the polishing liquid. For example, when the metal atom is an Fe atom, a solid containing Fe ion and Fe atom is applicable.
In the present specification, the content of metal atoms contained in the metal impurities in the polishing liquid is intended to be the content of metal atoms measured by ICP-MS (inductively coupled plasma mass spectrometry). The method for measuring the metal atom content using ICP-MS is as described in the examples described later.
Further, the content of metal atoms contained in the metal particles in the polishing liquid is intended to be the content of metal atoms measured by SNP-ICP-MS (single nanoparticle inductively coupled plasma mass spectrometry). The method for measuring the metal atom content using SNP-ICP-MS is as described in the examples described later.

The kind in particular of metal atom contained in a metal impurity is not restrict | limited, For example, Fe atom, Cu atom, Ag atom, Zn atom, etc. are mentioned.
Moreover, content of the at least 1 sort (s) of specific metal atom chosen from the group which consists of a Fe atom, Cu atom, Ag atom, and Zn atom among the said metal atoms is as follows.
When the polishing liquid contains one type of specific metal atom selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom, the content of the one type of specific metal atom is determined by the polishing liquid. It is preferably 0.001 to 200 mass ppb, more preferably 0.01 to 200 mass ppb, still more preferably 0.01 to 100 mass ppb, and particularly preferably 0.01 to 50 mass ppb based on the total mass. 0.01 to 20 mass ppb is most preferable.
When the content of the specific metal atom is in the above range with respect to the total mass of the polishing liquid, dishing and defects on the surface to be polished are less likely to occur, and stability over time is excellent.
Further, when two or more specific metal atoms selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms are contained, the content of each specific metal atom is based on the total mass of the polishing liquid. 0.001 to 200 mass ppb is preferable, 0.01 to 200 mass ppb is more preferable, 0.01 to 100 mass ppb is still more preferable, 0.01 to 50 mass ppb is particularly preferable, and 0.01 to 20 mass ppb. Is most preferred.
That is, for example, when two kinds of specific metal atoms of Fe atom and Cu atom are contained in the polishing liquid, both the content of Fe atom and the content of Cu atom are in the range of 0.001 to 200 mass ppb. It is preferable.

In addition, from the viewpoint of further reducing defects on the surface to be polished, inclusion of metal particles containing at least one specific metal atom selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms in the polishing liquid It is preferable to control the amount within a predetermined range. In other words, it is preferable that the amount of solid metal impurities in the polishing liquid is appropriately adjusted.
When the polishing liquid contains the metal particles, when the metal particles contain one kind of specific metal atom, the content of one kind is 0.01 to 50 mass ppb is preferable, and 0.01 to 8 mass ppb is more preferable.
When the polishing liquid contains the metal particles, when the metal particles contain two or more kinds of specific metal atoms, each content is 0.01 to 50 with respect to the total mass of the polishing liquid. Mass ppb is preferable, and 0.01 to 8 mass ppb is more preferable. That is, for example, when the metal particles containing Fe atoms and the metal particles containing Cu atoms are contained in the polishing liquid, both the Fe atom content and the Cu atom content are in the range of 0.01 to 50 mass ppb. It is preferable to be within.

The metal impurities containing the metal atoms may be added to the polishing liquid, or may be inevitably mixed in the chemical liquid in the polishing liquid manufacturing process. As a case where it is inevitably mixed in the manufacturing process of the polishing liquid, for example, when the metal impurity containing the metal atom is contained in a raw material (for example, an organic solvent) used for manufacturing the polishing liquid, and Although mixing (for example, contamination) etc. are mentioned at the manufacturing process of polishing liquid, it is not restrict | limited to the above.

The polishing liquid is calculated from the following formula (1): hydrogen peroxide and a specific metal atom selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom contained in the metal impurity. The content ratio T1 is preferably 30,000 to 500,000.
Formula (1): T1 = hydrogen peroxide content / total content of specific metal atoms selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms contained in metal impurities

Hydrogen peroxide generates hydroperoxo species having strong oxidizing power by decomposing using metal atoms such as Fe as a catalyst. On the other hand, the cobalt atom has a lower oxidation potential than the copper atom, which is a wiring metal element, and tends to be relatively easily oxidized. Therefore, when the object to be polished is a cobalt-containing layer, the surface to be polished is easily scraped by the generated hydroperoxo species, and excessive corrosion occurs, resulting in dishing. The When T1 is 30000 or more in the polishing liquid, the generation of the hydroperoxo species can be further suppressed, so that dishing is less likely to occur on the surface to be polished, and defects on the surface to be polished are less likely to occur.
Further, in the polishing liquid, when the T1 is 500,000 or less, the surface to be polished is sufficiently large because the difference between the hydrogen peroxide content and the metal ion content is sufficiently large (that is, the metal itself is difficult to oxidize). In addition, dishing is less likely to occur, and defects on the polished surface are less likely to occur.
When the polishing liquid is applied to the first polishing, the T1 is more preferably 110000 or less and even more preferably 80000 or less in that dishing and defects on the surface to be polished are less likely to occur.
When the polishing liquid is applied to the second polishing, the T1 is more preferably 100,000 or more, and further preferably 250,000 or more in that dishing and defects on the surface to be polished are less likely to occur.

<Compound represented by the general formula (1)>
The polishing liquid may contain a compound represented by the following general formula (1).
General formula (1):
N (R ¹ ) (R ² ) (R ³ )
In general formula (1), R ¹ to R ³ each independently represents a hydrogen atom or an alkyl group.

Examples of the compound represented by the general formula (1) include alkaline agents such as ammonia; alkanolamines such as ethanolamine, diethanolamine, triethanolamine, and triisopropanolamine;
The content of the compound represented by the general formula (1) in the polishing liquid is preferably 1500 mass ppb or less, more preferably 1000 mass ppb or less, and further preferably 250 mass ppb or less with respect to the total mass of the polishing liquid. It is preferably 8 mass ppb or less.
In the polishing liquid, when the content of the compound represented by the general formula (1) is 1500 mass ppb or less, the coordination to cobalt on the surface to be polished by the compound is suppressed, and on the other hand, due to the azole compound. A complex layer with cobalt is easily formed. As a result, dishing is less likely to occur on the surface to be polished, and defects on the surface to be polished are less likely to occur.
Although the minimum of content of the compound represented by the said General formula (1) in polishing liquid is not specifically limited, For example, it is 0.00001 mass ppb or more.
In addition, content of the compound represented by General formula (1) in the said polishing liquid can be measured using GCMS (gas chromatography mass spectrometry). The measurement conditions and the like are as described in the examples.

As described above, the polishing liquid is suitably used for CMP performed for planarization of a buried wiring (cobalt wiring) or the like when manufacturing a semiconductor integrated circuit device. When the polishing liquid is applied to the first polishing, the polishing liquid is preferably the polishing liquid of Embodiment 1 below, and when the polishing liquid is applied to the second polishing, the polishing liquid of the following Embodiment 2 is used. It is preferable that

<< Polishing liquid of Embodiment 1 >>
The polishing liquid of Embodiment 1 is
A polishing liquid for chemical mechanical polishing containing colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, and hydrogen peroxide,
The content of the colloidal silica having an association degree of 1 to 3 is 0.01 to 1% by mass with respect to the total mass of the polishing liquid.
As the organic acid, an amino acid is contained,
The azole compound contains at least two or more triazole compounds, and has a pH of 6.5 to 8.0.
When the polishing liquid and the cobalt substrate are contacted for 24 hours, a reaction layer (reaction layer 1) containing cobalt atoms is formed on the cobalt substrate, and the polishing liquid When the metal substrate is contacted with a barrier substrate made of any one metal selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn for 24 hours, the metal contains atoms of the metal on the barrier substrate. It is preferable that the polishing liquid forms a reaction layer (hereinafter also referred to as “reaction layer 2”) having a thickness of 0.01 to 5 nm.

The thickness of the reaction layer 2 is 0.01 nm or more, preferably 0.1 nm or more. The thickness of the reaction layer 2 is 5 nm or less, and preferably 3.0 nm or less.
If the thickness of the reaction layer 2 is 0.01 nm or more and 5 nm or less, the effect of the present invention is more excellent.

In this specification, the reaction layer 2 is a barrier made of any one metal (barrier metal) selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn having a surface to be polished of 10 mm × 10 mm. Reaction formed on the surface to be polished of the barrier substrate when a substrate (metal substrate made of a barrier metal) is immersed in 10 mL of polishing liquid and the barrier substrate and the polishing liquid are contacted at 25 ° C. for 24 hours. Intended layer.
When the barrier substrate is immersed in the polishing liquid, a laminate in which the barrier substrate and another substrate (for example, a silicon substrate) are stacked may be immersed in the polishing liquid.

The reaction layer 2 contains any one metal atom (barrier metal atom) selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn. The reaction layer 2 may further contain oxygen atoms and the like, and the reaction layer surface preferably contains a complex of components in the polishing liquid.
Here, the thickness of the reaction layer 2 is described in Examples using a scanning electron microscope (SEM) for the cross section of the barrier substrate after contacting the polishing liquid and the barrier substrate for 24 hours. The thickness obtained by observing by this method is intended.

The polishing liquid only needs to be able to form the reaction layer 2 on the barrier substrate made of any one metal selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn according to the predetermined conditions. It is preferable that the reaction layer 2 can be formed on each of a substrate made of Ta, a substrate made of TaN, a substrate made of Ti, a substrate made of TiN, a substrate made of Ru, and a substrate made of Mn.

The polishing liquid is preferably adjusted so that the polishing rate ratio R1 calculated from the following formula (3) is 250 to 2500 from the viewpoint of further suppressing the occurrence of dishing on the surface to be polished.
Formula (3):
R1 = Cobalt substrate polishing rate with the polishing solution / Barrier substrate polishing rate with the polishing solution Generally, the polishing of the barrier layer has a larger contribution of mechanical polishing than chemical polishing. In other words, even if the reaction layer 2 is formed, the polishing rate does not increase greatly. For this reason, when making polishing rate ratio R1 into the said predetermined | prescribed numerical range, it is preferable to adjust so that the polishing rate of the cobalt containing layer by polishing liquid may go up. The same applies to the polishing rate ratio R2 described later.

The colloidal silica having an association degree of 1 to 3, the organic acid, the azole compound, and the optional component contained in the polishing liquid of Embodiment 1 are as described above, and the preferred embodiments are also the same. Moreover, it is as above-mentioned also about the said reaction layer 1, A preferable aspect is also the same.

<< Polishing liquid of Embodiment 2 >>
The polishing liquid of Embodiment 2 is
A polishing liquid for chemical mechanical polishing containing colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, and hydrogen peroxide,
The content of the colloidal silica having the association degree of 1 to 3 is 0.5 to 5% by mass with respect to the total mass of the polishing liquid.
As the azole compound, a triazole compound is contained,
pH is 8.0-10.5,
When the polishing liquid and the cobalt substrate are brought into contact for 24 hours, a reaction layer (corresponding to the “reaction layer 1”) having a thickness of 0.5 to 20 nm containing cobalt atoms is formed on the cobalt substrate. In addition,
When the polishing liquid is brought into contact with a barrier substrate made of any one metal selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn for 24 hours, atoms of the metal on the barrier substrate A reaction layer containing 0.01 to 5 nm in thickness (corresponding to the above “reaction layer 2”) is formed,
When the polishing liquid is brought into contact with an insulating film substrate made of any one of the inorganic components selected from the group consisting of SiOx and SiOC for 24 hours, the thickness of the inorganic film containing the inorganic component on the insulating film substrate is 0.01 to A polishing liquid in which a 10 nm reaction layer (hereinafter also referred to as “reaction layer 3”) is formed is preferable.

The thickness of the reaction layer 3 is 0.01 nm or more, preferably 0.1 nm or more. The thickness of the reaction layer 3 is 10 nm or less, preferably 5 nm or less.
If the thickness of the reaction layer 3 is 0.01 nm or more and 10 nm or less, the effect of the present invention is more excellent.

In the present specification, the reaction layer 3 is obtained by immersing an insulating film substrate made of any one inorganic component selected from the group consisting of SiOx and SiOC having a surface to be polished of 10 mm × 10 mm in 10 mL of polishing liquid, The reaction layer formed on the surface to be polished of the insulating film substrate when the insulating film substrate and the polishing liquid are brought into contact at 25 ° C. for 24 hours is intended.
Note that when the insulating film substrate is immersed in the polishing liquid, a laminate in which the insulating film substrate and another substrate (for example, a silicon substrate) are stacked may be immersed in the polishing liquid.

The reaction layer 3 contains the inorganic component. The reaction layer 3 may further contain oxygen atoms and the like, and the reaction layer surface preferably contains a complex of components in the polishing liquid.
Here, the thickness of the reaction layer 3 is determined by measuring the cross section of the insulating film substrate after contacting the polishing liquid and the insulating film substrate for 24 hours using a scanning electron microscope (SEM). The thickness obtained by observation by the method described in 1 is intended.

The polishing liquid only needs to be able to form the reaction layer 3 on the insulating film substrate made of any one of the inorganic components selected from the group consisting of SiOx and SiOC under the predetermined conditions. It is preferable that the reaction layer 3 can be formed on each of all the substrates.

The polishing liquid is preferably adjusted so that the polishing rate ratio R2 calculated from the following formula (4) is 0.01 to 2.0 from the viewpoint of further suppressing the occurrence of dishing on the surface to be polished. . Further, it is preferable that the polishing rate ratio R3 calculated from the following formula (5) is adjusted to be 0.05 to 2.0.
Formula (4):
R2 = Polishing speed of cobalt substrate with the above polishing liquid / Polishing speed of barrier substrate with the above polishing liquid Formula (5):
R3 = Polishing rate of cobalt substrate with the polishing solution / Polishing rate of insulating film substrate with the polishing solution

The colloidal silica having an association degree of 1 to 3, the organic acid, the azole compound, and the optional component contained in the polishing liquid of Embodiment 2 are as described above. The reaction layer 1 and the reaction layer 2 are also as described above.

[Method for preparing polishing liquid]
The polishing liquid can be produced by a known method. For example, it can manufacture by mixing each said component. The order and / or timing of mixing the above components is not particularly limited, and colloidal silica having an association degree of 1 to 3 may be previously dispersed in water adjusted in pH, and predetermined components may be mixed sequentially. Further, hydrogen peroxide, water, or hydrogen peroxide and water may be separately stored until immediately before the use of the abrasive and mixed immediately before use. Moreover, it is preferable to manufacture the said polishing liquid by the following method which has a dilution process which dilutes with water just before use.

[Production method of polishing liquid]
A method for producing a polishing liquid according to one embodiment of the present invention provides a polishing liquid stock solution containing colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, and hydrogen peroxide. It is a method for producing a polishing liquid, which comprises a step of mixing water to obtain the above polishing liquid (hereinafter also referred to as “dilution step”).

[Dilution process]
The dilution step is a step of obtaining a polishing liquid by mixing water with a polishing liquid stock solution containing predetermined components.
The aspect of the polishing liquid is as described above. Moreover, it does not restrict | limit especially as a method of mixing water, A well-known method can be used.

<Polishing liquid stock solution>
The polishing liquid stock solution used in the dilution step is a polishing liquid stock solution containing colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, and hydrogen peroxide, and further mixed with water. Thus, the polishing liquid stock solution is used for producing the polishing liquid.
As the polishing liquid stock solution, it is sufficient that the polishing liquid is obtained by mixing a solvent such as water. In addition to the above components, an organic solvent, a surfactant, a hydrophilic polymer, a pH adjuster, a pH buffer, if desired. You may contain an agent, a cobalt anticorrosive, etc.
The stock solution of polishing liquid is preferably a liquid obtained by concentrating the polishing liquid used in CMP for 2 to 50 times. That is, the polishing liquid stock solution is used after being diluted 2 to 50 times. Water is preferably used for dilution.
The method for producing the polishing liquid stock solution is not particularly limited, and can be produced by a known method. For example, it can manufacture by mixing each said component. The order of mixing the above components is not particularly limited, and colloidal silica may be dispersed in advance in water and / or an organic solvent whose pH has been adjusted, and predetermined components may be sequentially mixed.
Further, when the polishing liquid stock solution is diluted 2 to 50 times with water, the pH change before and after dilution is preferably 0.01 to less than 1.
The inventor examined the performance state of the polishing stock solution before and after dilution. When the pH change before and after dilution was 0.01 to less than 1, it was confirmed that the performance change due to dilution was suppressed. ing. Specifically, it was confirmed that when the pH change before and after the dilution of the polishing liquid stock solution is 0.01 or more, the performance change accompanying the dilution does not substantially occur. On the other hand, when the pH change before and after dilution of the polishing liquid stock solution is less than 1, it has been confirmed that the performance change accompanying dilution is small and the performance is not significantly impaired.

Further, as another aspect of the method for producing the polishing liquid, a concentrated liquid of the polishing liquid containing a predetermined component is prepared, and hydrogen peroxide or hydrogen peroxide and water are added thereto to obtain predetermined characteristics. The method of manufacturing the polishing liquid which has is mentioned.

[Polishing liquid stock container]
The polishing liquid stock solution container of the present invention comprises the above polishing liquid stock solution and a container made of a metal material containing no iron and containing the above polishing liquid stock solution.
Here, the “metal material not containing iron” intends a metal material substantially free of iron. For example, the content of iron atoms is 30% or less, preferably 20% or less, based on the total atomic weight. Intended for metal materials.
The above-mentioned polishing liquid stock solution is a metal material that does not contain iron (hereinafter referred to as “non-ferrous metal” from the viewpoint that the impurity content hardly increases even when the polishing liquid stock solution is stored for a predetermined period of time, and that the decomposition of hydrogen peroxide is suppressed. It is desirable to be accommodated in a container formed from “material”. The said container should just be formed with the non-ferrous metal material in the inner wall which contacts polishing liquid stock solution, and it does not specifically limit about another structure.
As a container having an inner wall formed of a nonferrous metal material, the inner wall is coated with at least one material selected from the group consisting of a nonmetallic material and an electropolished nonmetallic material, or the inner wall is made of a material. A formed container is preferred.
In the present specification, the term “coating” means that the inner wall is covered with the material. As an aspect in which the inner wall is covered with the material, 70% or more of the total surface area of the inner wall is preferably covered with the material.

Non-metallic materials include, for example, polyethylene resin, polypropylene resin, polyethylene-polypropylene resin, ethylene tetrafluoride resin, ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer, ethylene tetrafluoride-hexafluoropropylene copolymer resin Resin materials such as tetrafluoroethylene-ethylene copolymer resin, ethylene trifluoride-ethylene copolymer resin, vinylidene fluoride resin, ethylene trifluoride-chloroethylene copolymer resin, and vinyl fluoride resin; chromium, and And metal materials such as nickel.

Of these, a nickel-chromium alloy is preferred as the metal material.
The nickel-chromium alloy is not particularly limited, and a known nickel-chromium alloy can be used. Among these, a nickel-chromium alloy having a nickel content of 40 to 75% by mass and a chromium content of 1 to 30% by mass is preferable.
Examples of the nickel-chromium alloy include Hastelloy (trade name, the same applies hereinafter), Monel (trade name, the same applies hereinafter), Inconel (product name, the same applies hereinafter), and the like. More specifically, Hastelloy C-276
(Ni content 63% by mass, Cr content 16% by mass), Hastelloy-C (Ni content 60% by mass, Cr content 17% by mass), Hastelloy C-22 (Ni content 61% by mass, Cr content 22% by mass).
Further, the nickel-chromium alloy may further contain boron, silicon, tungsten, molybdenum, copper, cobalt, and the like in addition to the above-described alloy as necessary.

The method for electropolishing the metal material is not particularly limited, and a known method can be used. For example, the methods described in paragraphs [0011]-[0014] of JP-A-2015-227501 and paragraphs [0036]-[0042] of JP-A-2008-264929 can be used.

Note that the metal material may be buffed. The buffing method is not particularly limited, and a known method can be used. The size of the abrasive grains used for the buffing finish is not particularly limited, but is preferably # 400 or less in that the irregularities on the surface of the metal material are likely to be smaller.
The buffing is preferably performed before the electrolytic polishing.

[Chemical mechanical polishing method]
In the chemical mechanical polishing method according to one embodiment of the present invention, while supplying the polishing liquid to the polishing pad attached to the polishing surface plate, the polishing surface of the object to be polished is brought into contact with the polishing pad, A chemical mechanical polishing method (hereinafter, also referred to as “polishing step”) including a step of moving the polishing body and the polishing pad relatively to polish the surface to be polished to obtain a polished target body (hereinafter also referred to as “polishing step”). Also referred to as “CMP method”.

[Polished object]
The object to be polished to which the CMP method according to the above embodiment can be applied is not particularly limited, but the object to be polished (metal) containing at least one cobalt-containing layer selected from the group consisting of cobalt and a cobalt alloy. A substrate with a layer) is preferred.
Although it does not restrict | limit especially as said cobalt alloy, The cobalt alloy containing nickel is preferable.
When the cobalt alloy contains nickel, the nickel content is preferably 10% by mass or less, more preferably 1% by mass or less, still more preferably 0.1% by mass or less, and 0.00001% by mass in the total mass of the cobalt alloy. % Or more is preferable. The electrode may be a through silicon via.

The object to be polished used in the CMP method according to the above embodiment can be manufactured by the following method.
First, an interlayer insulating film such as silicon dioxide is laminated on a silicon substrate. Next, a concave portion (substrate exposed portion) having a predetermined pattern is formed on the surface of the interlayer insulating film by a known means such as resist layer formation or etching to form an interlayer insulating film composed of convex portions and concave portions. On this interlayer insulating film, as a barrier layer covering the interlayer insulating film along the unevenness of the surface, any one selected from the group consisting of metal or metal nitride (for example, Ta, TaN, Ti, TiN, Ru, and Mn) Or a single metal or metal nitride is preferable.) Or the like is formed by vapor deposition or CVD (chemical vapor deposition). Further, a cobalt-containing layer (hereinafter also referred to as a metal layer) made of at least one selected from the group consisting of cobalt and a cobalt alloy that covers the barrier layer so as to fill the recesses is deposited, plated, CVD, or the like. Thus, an object to be polished having a laminated structure is obtained. The thicknesses of the interlayer insulating film, barrier layer, and metal layer are preferably about 0.01 to 2.0 μm, 1 to 100 nm, and 0.01 to 2.5 μm, respectively.
The material constituting the barrier layer is not particularly limited, and a known low-resistance metal material can be used. As the low-resistance metal material, Ta, TaN, Ti, TiN, Ru, and Mn are more preferable.

(Polished surface)
In the object to be polished used in the CMP method according to the above embodiment, the surface to be polished is not particularly limited.
The metal wiring manufacturing process using the object to be polished is usually because the metal atom contained in the barrier layer in the object to be polished and the metal atom contained in the cobalt-containing layer are different from each other in chemical and physical properties. CMP is performed in two stages. That is, as described above, CMP is performed on the cobalt-containing layer in the first step, and CMP on the barrier layer is performed in the second step. Note that dishing in which the metal wiring is excessively polished is likely to occur in the first-stage CMP process, and in the second-stage CMP process, the fine metal wiring is densely arranged along with the dishing. Erosion is likely to occur due to excessive polishing of the insulating film at the location (the insulating film is disposed between the metal wirings).

[Polishing equipment]
The polishing apparatus capable of performing the CMP method is not particularly limited, and a known chemical mechanical polishing apparatus (hereinafter also referred to as “CMP apparatus”) can be used.
As a CMP apparatus, for example, a holder that holds an object to be polished (for example, a semiconductor substrate) having a surface to be polished and a polishing pad to which a polishing pad is attached (a motor that can change the number of revolutions is attached). A general CMP apparatus provided with a board can be used. As a commercial product, for example, Reflexion (manufactured by Applied Materials) can be used.

<Polishing pressure>
In the CMP method according to the above embodiment, polishing is preferably performed at a polishing pressure, that is, a pressure generated on the contact surface between the surface to be polished and the polishing pad of 3000 to 25000 Pa, and more preferably 6500 to 14000 Pa. .

<Rotation speed of polishing surface plate>
In the CMP method according to the above embodiment, the polishing is preferably performed at a rotation speed of the polishing platen of 50 to 200 rpm, more preferably 60 to 150 rpm.
In order to relatively move the polishing body and the polishing pad, the holder may be further rotated and / or swayed, the polishing platen may be rotated on a planetary surface, or the belt-like polishing pad may be elongated. It may be moved linearly in one direction. The holder may be in a fixed, rotating, or swinging state. These polishing methods can be appropriately selected depending on the surface to be polished and / or the polishing apparatus as long as the polishing body and the polishing pad are moved relatively.

<Polishing liquid supply method>
In the CMP method according to the above embodiment, the polishing liquid is continuously supplied to the polishing pad on the polishing surface plate by a pump or the like while the surface to be polished is polished. Although there is no restriction | limiting in this supply amount, it is preferable that the surface of a polishing pad is always covered with polishing liquid. The aspect of the polishing liquid is as described above.

The CMP method according to the above embodiment may further include the following steps before the polishing step.
Examples of the step include a step of mixing water with a polishing solution stock solution containing colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, and hydrogen peroxide. The aspects of the polishing liquid, the polishing liquid stock solution, and the concentrated liquid are as described above.

Hereinafter, the present invention will be described in more detail based on examples. The materials, amounts used, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below. Unless otherwise specified, “%” means “mass%” and “ppb” means “mass ppb”.

[Purification of raw materials]
Each raw material and each catalyst used in each Example shown below are those purified in advance by distillation, ion exchange, filtration or the like using a high purity grade having a purity of 99% by mass or more.

The ultrapure water used for the preparation of each polishing liquid was purified by the method described in JP-A-2007-254168. Thereafter, it was used after confirming that the content of each element of Na, Ca and Fe was less than 10 mass ppt with respect to the total mass of each chemical solution, by measurement by the SNP-ICP-MS method described later.

The preparation, filling, storage, and analysis of the polishing liquids of the examples and comparative examples were all performed in a clean room that satisfies ISO class 2 or lower. Moreover, the container used in each Example and the comparative example was used after wash | cleaning with the polishing liquid of each Example or a comparative example. In order to improve the measurement accuracy, the measurement of the content of metal components and the measurement of the content of water are performed by concentrating to 1/100 in terms of volume, and measuring those below the detection limit in normal measurement. The content was calculated in terms of the concentration of the previous polishing liquid.

[Example 1A]
Each component shown below was mixed to prepare a chemical mechanical polishing liquid.
Colloidal silica (degree of association: 2, average primary particle size: 35 nm, product name “PL3”, manufactured by Fuso Chemical Industries) 0.1 mass%
・ Glycine (corresponds to amino acid) 1.5% by mass
・ 5-methylbenzotriazole (corresponds to azole compound containing benzotriazole skeleton) 0.001% by mass
・ 3-Amino-1,2,4-triazole (corresponds to a compound not containing benzotriazole skeleton and a compound containing 1,2,4-triazole skeleton) 0.2% by mass 1.0% by mass
・ Ethylene glycol (corresponds to organic solvent, partly used as a solvent to dissolve 5-methylbenzotriazole) 0.05% by mass
・ Hydrogen peroxide (corresponds to oxidizing agent) 1.0% by mass
・ Water (pure water) remaining

The pH of the polishing liquid in Table 1 was adjusted to a predetermined value using sulfuric acid and / or potassium hydroxide as necessary.

In this example, “Table 1” refers to Table 1A1, Table 1A2, Table 1B1, Table 1B2, Table 1C1, Table 1C2, Table 1D1, and Table 1D2.

[Examples 2A to 83A, Comparative Examples 1A to 5A]
Each component shown in Table 1 was mixed by the same method as in Example 1A to obtain each polishing liquid. In addition, each abbreviation in Table 1 shows the following compounds.
PL3 (Colloidal silica, product name “PL3”, manufactured by Fuso Chemical Industries, association degree: 2, average primary particle size: 35 nm)
PL2 (Colloidal silica, product name “PL2”, manufactured by Fuso Chemical Industry Co., Ltd., degree of association: 2, average primary particle size: 25 nm)
PL3L (Colloidal silica, product name “PL3L”, manufactured by Fuso Chemical Industry Co., Ltd., degree of association: 1, average primary particle size: 35 nm)
PL3H (Colloidal silica, product name “PL3H”, manufactured by Fuso Chemical Industries, association degree: 3, average primary particle size: 35 nm)
ST-PS-MO (Colloidal silica, product name “ST-PS-MO”, manufactured by Nissan Chemical Industries, association degree: over 3, average primary particle size: 20 nm)
Gly (corresponds to glycine and amino acid)
Ala (corresponds to alanine and amino acid)
Asp (corresponds to aspartic acid and amino acid)
NMG (N-methylglycine, corresponding to amino acids)
・ 5-MBTA (corresponds to 5-methylbenzotriazole, azole compounds containing benzotriazole skeleton)
BTA (corresponds to azole compounds containing benzotriazole or benzotriazole skeleton)
・ 5,6-DMBTA (corresponds to 5,6-dimethylbenzotriazole and azole compounds containing benzotriazole skeleton)
-5-ABTA (corresponds to azole compounds containing 5-aminobenzotriazole or benzotriazole skeleton)
3-AT (corresponds to azole compounds not containing 3-amino-1,2,4-triazole, benzotriazole skeleton and azole compounds containing 1,2,4-triazole skeleton)
-1,2,4-Tri (corresponds to azole compounds not containing a 1,2,4-triazole, benzotriazole skeleton and azole compounds containing a 1,2,4-triazole skeleton)
-3,5-DP (corresponds to 3,5-dimethylpyrazole, azole compounds not containing benzotriazole skeleton, and azole compounds containing pyrazole skeleton (pyrazole compounds))
Pyraz (corresponds to pyrazole, an azole compound not containing a benzotriazole skeleton, and an azole compound containing a pyrazole skeleton)
・ Imidaz (corresponds to imidazole, azole compound not containing benzotriazole skeleton, and azole compound containing imidazole skeleton (imidazole compound))
・ 5-ATZ (corresponds to 5-aminotetrazole and azole compounds not containing benzotriazole skeleton)
・ ETG (Ethylene glycol, applicable to organic solvents)
EtOH (corresponds to ethanol and organic solvents)
・ PG (corresponds to propylene glycol and organic solvents)
・ 4-HA (corresponds to 4-hydroxybenzoic acid and organic acid)
・ 2-HA (corresponds to 2-hydroxybenzoic acid and organic acid)
・ PA (corresponds to phthalic acid and organic acid)
SA (corresponds to salicylic acid and organic acid)
Ant (corresponds to anthranilic acid and organic acid)
TMT (corresponds to trimellitic acid and organic acid)
・ N-cocoyl sarcosinate (corresponds to N-cocoyl sarcosinate and cobalt anticorrosive)
・ N-lauroyl sarcosinate (corresponds to N-lauroyl sarcosinate and cobalt anticorrosive)
・ N-oleoyl sarcosinate (corresponds to N-oleoyl sarcosinate, cobalt anticorrosive)
・ N-myristoy sarcosinate (corresponds to myristoyl sarcosinate, cobalt anticorrosive)
・ N-myristoy glycine (corresponds to N-myristoylglycine, a cobalt anticorrosive)
・ N-stearoyl sarcosinate (corresponds to N-stearoyl sarcosinate, cobalt anticorrosive)
・ N-lauroyl glycine (corresponds to N-lauroylglycine, a cobalt anticorrosive)
・ N-palmitoyl glycine (corresponds to N-palmitoylglycine, a cobalt anticorrosive)
・ N-lauroyl glutamate (corresponds to N-lauroyl glutamic acid and cobalt anticorrosive)
N-cocoyl glutamate (corresponds to N-cocoyl glutamic acid and cobalt anticorrosive)
Potassium N-coyl glutamate (corresponds to potassium N-cocoyl glutamate and cobalt anticorrosive)
Potassium N-lauroyl sarcosinate (corresponds to potassium N-lauroyl sarcosinate, a cobalt anticorrosive)
・ N-lauroyl alaninate (corresponds to N-lauroyl alaninate, cobalt anticorrosive)
・ N-myristoylaninate (corresponds to N-myristoyl alaninate, cobalt anticorrosive)
Potassium N-cocoyl alaninate (corresponds to N-cocoyl alaninate potassium and cobalt anticorrosive)
RE-610 (Product name “Rhodafac RE-610”, manufactured by Rhodia, applicable to surfactant)
MD-20 (product name “Surfynol MD-20”, manufactured by Air Products, applicable to surfactant)
DBSH (corresponds to dodecylbenzenesulfonic acid, surfactant)
-PHEAA (corresponds to N- (2-hydroxyethyl) acrylamide polymer, weight average molecular weight 20000, hydrophilic polymer)
PAA (corresponds to polyacrylic acid and hydrophilic polymer)
PEIEO (polyethyleneimine having an ethyleneoxy chain having a repeating unit represented by the following formula, HLB value 18)

[Example 1B]
Each component shown below was mixed to prepare a chemical mechanical polishing liquid.
Colloidal silica (degree of association: 2, average primary particle size: 35 nm, product name “PL3”, manufactured by Fuso Chemical Industries) 3.0% by mass
・ CA (corresponds to citric acid and organic acid) 0.003% by mass
・ Male (corresponds to maleic acid and organic acid) 0.05% by mass
・ Benzotriazole (corresponds to azole compound containing benzotriazole skeleton) 0.1% by mass
3-amino-1,2,4-triazole (corresponds to a compound not containing a benzotriazole skeleton and a compound containing a 1,2,4-triazole skeleton) 0.05% by mass
・ Hydrogen peroxide (corresponds to oxidizing agent) 1.0% by mass
・ Ethylene glycol (corresponds to organic solvent, partly used as a solvent to dissolve 5-methylbenzotriazole) 0.05% by mass
・ Water (pure water) remaining

The pH of the polishing liquid in Table 2 was adjusted to a predetermined value using sulfuric acid and / or potassium hydroxide as necessary.

In this example, “Table 2” refers to Table 2A1, Table 2A2, Table 2A3, Table 2B1, Table 2B2, Table 2B3, Table 2C1, Table 2C2, Table 2C3, Table 2D1, Table 2D2, and Table 2D3. .

[Examples 2B to 82B, Comparative Examples 1B to 3B]
Each component shown in Table 2 was mixed by the same method as in Example 1B to obtain each polishing liquid. Each abbreviation in Table 2 indicates the following compounds and the like. In addition, about each abbreviation in Table 2, the same abbreviation in Table 1 is as above-mentioned.
CA (corresponds to citric acid and organic acid)
・ Succinic acid (corresponds to organic acid)
・ Malic acid (corresponds to organic acid)
・ Malonic acid (corresponds to organic acid)
・ Male (corresponds to maleic acid and organic acid)

[Measurement of average particle diameter ratio (T2) of colloidal silica before and after CMP]
The average particle diameter of the colloidal silica before and after CMP was measured by the following method, and the average particle diameter ratio (T2) of the colloidal silica before and after CMP was determined by the following formula (2). The results are shown in Tables 1 and 2.
≪Measurement conditions≫
Using a particle size distribution analyzer SALD-2300 (manufactured by Shimadzu Corporation), the particle size distribution of the abrasive particles in the polishing liquid before CMP was measured to determine the average particle size. Further, the polishing liquid after CMP was recovered, and the average particle diameter of the abrasive particles in the recovered polishing liquid was determined by the same method. Using the obtained numerical value, T2 obtained from the following formula was calculated.
Formula (2):
T2 = average particle diameter after chemical mechanical polishing / average particle diameter before chemical mechanical polishing

[Measurement of reaction layer thickness]
<Measurement of reaction layer thickness when cobalt model film is used as polished surface>
A silicon substrate on which cobalt having a thickness of 1500 nm is deposited and cut into about 10 mm square is left in a polyethylene cup having an internal volume of about 100 mL containing 10 mL of the above polishing liquid at room temperature (about 25 ° C.) for 24 hours. Soaked. After immersion, the sample taken out from the polishing liquid was washed with water and further air-dried using nitrogen to obtain a sample having a reaction layer formed on the cobalt surface.
About this sample, the cross-section formation processing by the focused ion beam processing apparatus (FIB: Focused Ion Beam) and the cross-sectional observation by a scanning electron microscope (SEM) were performed on the measurement conditions shown below, and the thickness of the reaction layer was measured. The results are shown in Tables 1 and 2.
(FIB processing conditions)
Apparatus: FB-2000A acceleration voltage manufactured by Hitachi, Ltd .: 30 kV
Pretreatment: platinum sputter coating → carbon deposition → tungsten deposition (SEM measurement conditions)
Equipment: Hitachi, Ltd. S-900 acceleration voltage: 3kV
Pretreatment: Platinum sputter coating

<Measurement of the thickness of the reaction layer when any one model film selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn is used as the polished surface>
A silicon substrate on which Ta with a thickness of 1500 nm is deposited is cut into a square of about 10 mm and left in a polyethylene cup with an internal volume of about 100 mL containing 10 mL of the above polishing liquid at room temperature (about 25 ° C.) for 24 hours. Soaked. After immersion, the sample taken out from the polishing liquid was washed with water and further air-dried using nitrogen to obtain a sample having a reaction layer formed on the Ta surface.
About this sample, the cross-section formation processing by the focused ion beam processing apparatus (FIB: Focused Ion Beam) and the cross-sectional observation by a scanning electron microscope (SEM) were performed on the measurement conditions shown below, and the thickness of the reaction layer was measured. The results are shown in Tables 1 and 2.
Further, for each of TaN, Ti, TiN, Ru, and Mn metals, a model film was prepared by the same method as described above, and the thickness of each reaction layer was measured (results are shown in Tables 1 and 2).

<Measurement of the thickness of the reaction layer when any one model film selected from the group consisting of SiOx and SiOC is used as the surface to be polished>
A silicon substrate on which SiOx having a thickness of 1500 nm is deposited is cut into a square of about 10 mm, and left in a polyethylene cup having an internal volume of about 100 mL containing 10 mL of the above polishing liquid at room temperature (about 25 ° C.) for 24 hours. Soaked. After immersion, the sample taken out from the polishing liquid was washed with water and further air-dried using nitrogen to obtain a sample having a reaction layer formed on the SiOx surface.
About this sample, the cross-section formation processing by the focused ion beam processing apparatus (FIB: Focused Ion Beam) and the cross-sectional observation by a scanning electron microscope (SEM) were performed on the measurement conditions shown below, and the thickness of the reaction layer was measured. The results are shown in Table 2.
Also for SiOC, a model film was prepared by the same method as described above, and the thickness of the reaction layer was measured (results are shown in Table 2).

[Various types of determination]
<Content of the compound represented by the general formula (1)>
The content of the compound represented by the general formula (1) contained in the polishing liquid prepared in each Example and Comparative Example was determined by gas chromatograph mass spectrometer (product name “GCMS-2020”, Shimadzu Corporation). ). The measurement conditions are shown below.
The quantification using a gas chromatograph mass spectrometer was performed using a sample in which hydrogen fluoride was added to the polishing liquid to completely dissolve the abrasive particles, and then the pH was adjusted to 10 or higher.

≪Measurement conditions≫
Capillary column: InertCap 5MS / NP 0.25 mm I.D. D. × 30m df = 0.25μm
Sample introduction method: Split 75 kPa Pressure constant vaporization chamber temperature: 230 ° C
Column oven temperature: 80 ° C. (2 min) -500 ° C. (13 min) Temperature rising rate 15 ° C./min
Carrier gas: Helium septum purge flow rate: 5 mL / min
Split ratio: 25: 1
Interface temperature: 250 ° C
Ion source temperature: 200 ° C
Measurement mode: Scan m / z = 85 to 500
Sample introduction volume: 1 μL

<Content of specific metal atom>
(Content of specific metal atoms contained in metal impurities)
The content of the specific metal atom contained in the metal impurities in the polishing liquid prepared in each Example and Comparative Example was measured using Agilent 8800 Triple Quadrupole ICP-MS (for semiconductor analysis, option # 200).

≪Measurement conditions≫
The sample introduction system used was a quartz torch, a coaxial PFA (perfluoroalkoxyalkane) nebulizer (for self-priming), and a platinum interface cone. The measurement parameters for the cool plasma conditions are as follows.
-RF (Radio Frequency) output (W): 600
Carrier gas flow rate (L / min): 0.7
-Makeup gas flow rate (L / min): 1
-Sampling depth (mm): 18

(Content of specific metal atoms contained in metal particles)
Measurement by SNP-ICP-MS (Single Nano Particle-Inductively Coupled Plasma-Mass Spectrometry) The content of the specific metal atom contained in the metal particles was measured using “Nexion 350S” manufactured by Perkinelmer.
The quantification by SNP-ICP-MS was performed using a sample in which hydrogen fluoride was added to the polishing liquid to completely dissolve the abrasive particles, and then the pH was adjusted to 10 or more.
1) Preparation of standard substance Ultra pure water is weighed into a standard glass container, and metal particles to be measured with a median diameter of 50 nm are added to a concentration of 10,000 particles / ml, followed by an ultrasonic cleaner. The dispersion treated for 30 minutes was used as a standard substance for transport efficiency measurement.
2) Measurement conditions Using a PFA coaxial nebulizer, a quartz cyclone spray chamber, and a quartz 1 mm inner diameter torch injector, the liquid to be measured was sucked at about 0.2 mL / min. The oxygen addition amount was 0.1 L / min, the plasma output was 1600 W, and cell purge with ammonia gas was performed. The time resolution was 50 us.
3) The content of specific metal atoms contained in the metal particles was measured using the following analysis software attached to the manufacturer.
-Content of specific metal atoms contained in metal particles: Synistix nano application module dedicated to nanoparticle analysis “SNP-ICP-MS”

[Polishing speed, dishing evaluation, and erosion evaluation]
Polishing is performed while supplying the polishing liquid to the polishing pad under the following conditions. For Examples 1A to 83A and Comparative Examples 1A to 5A, the polishing rate and dishing are evaluated. For Examples 1B to 82B, the polishing rate and dishing are evaluated. And erosion was evaluated.
Polishing device: Reflexion (manufactured by Applied Materials)
・ Substance to be polished (wafer):
(1) For polishing rate calculation; each of the above model films (Co film, Ta film, SiOx film, TaN film, Ti film, TiN film, Mn film, Ru film, or SiOC film) having a thickness of 1.5 μm on a silicon substrate A blanket wafer having a diameter of 300 mm.
(2) For dishing evaluation;
Examples 1A to 83A, Comparative Examples 1A to 5A:
A substrate with a pattern of cobalt wiring (made by International SEMATECH, an insulating layer made of SiOx on a silicon substrate having a thickness of 5000 mm, and then patterned with a “SEMATECH 854” mask (L / S = 10 μm / 10 μm) A test substrate in which a barrier metal layer (barrier metal: Ta) having a thickness of 100 mm and a cobalt layer having a thickness of 7500 mm are sequentially stacked.
Examples 1B-82B:
A substrate with a pattern of cobalt wiring (made by International SEMATECH, an insulating layer made of SiOx on a silicon substrate having a thickness of 5000 mm, and then patterned with a “SEMATECH 854” mask (L / S = 10 μm / 10 μm) A test substrate in which a barrier metal layer (barrier metal: Ta) having a thickness of 100 mm and a cobalt layer having a thickness of 7500 mm are sequentially stacked.
(3) For erosion evaluation;
A substrate with a pattern of cobalt wiring (made by International SEMATECH, an insulating layer made of SiOx on a silicon substrate having a thickness of 5000 mm, and then patterned with a “SEMATECH 854” mask (L / S = 9 μm / 1 μm) A test substrate in which a barrier metal layer (barrier metal: Ta) having a thickness of 100 mm and a cobalt layer having a thickness of 7500 mm are sequentially stacked.

Polishing pad: IC1010 (Rodel)
・ Polishing conditions;
Polishing pressure (contact pressure between the surface to be polished and the polishing pad): 1.5 psi (in this specification, psi means pound-force per square inch; 1 psi = 6894.76 Pa) Intended)
Polishing liquid supply rate: 200 ml / min
Polishing platen rotation speed: 110rpm
Polishing head rotation speed: 100 rpm

(Evaluation methods)
Examples 1A to 83A, Comparative Examples 1A to 5A:
Polishing rate calculation: The blanket wafer of (1) was polished for 60 seconds, and the metal film thickness before and after polishing was calculated from the electrical resistance value at 49 equally spaced locations on the wafer surface. The average value of the values obtained by dividing by was used as the polishing rate (unit: nm / min).

Evaluation of dishing: In addition to the time until the cobalt in the non-wiring portion is completely polished on the pattern wafer of (2), the polishing is further performed for 20% of the time, and the line and space portion (line A step of 10 μm and a space of 10 μm was measured with a contact-type step gauge Dektak V320Si (manufactured by Veeco) and evaluated according to the following criteria. In addition, evaluation "G" or more is a practical use range.
A: Dishing is 5 nm or less.
B: Dishing is more than 5 nm and 8 nm or less.
C: Dishing is more than 8 nm and 12 nm or less.
D: Dishing is more than 12 nm and 15 nm or less.
E: Dishing is more than 15 nm and 18 nm or less.
F: Dishing is more than 18 nm and 21 nm or less.
G: Dishing is more than 21 nm and 25 nm or less.
H: Dishing is over 25 nm.

Examples 1B to 82B, Comparative Examples 1B to 3B:
Polishing rate calculation: The blanket wafer of (1) was polished for 60 seconds, and the metal film thickness before and after polishing was calculated from the electrical resistance value at 49 equally spaced locations on the wafer surface. The average value of the values obtained by dividing by was used as the polishing rate (unit: nm / min).

Evaluation of erosion: In addition to the time until the cobalt in the non-wiring portion is completely polished on the pattern wafer of (3), it is further polished for one minute, and the line and space portion (line 9 μm, space 1 μm) ) Was measured with a contact step meter Dektak V320Si (manufactured by Veeco) and evaluated according to the following criteria. In addition, evaluation "G" or more is a practical use range.
A: Erosion is 3 nm or less.
B: Erosion is more than 3 nm and less than 5 nm.
C: Erosion is more than 5 nm and 10 nm or less.
D: Erosion is more than 10 nm and 15 nm or less.
E: Erosion is more than 15 nm and 20 nm or less.
F: Erosion is more than 20 nm and 25 nm or less.
G: Erosion is more than 25 nm and 30 nm or less.
H: Erosion is over 30 nm.

(Defect evaluation)
The pattern wafer that had been subjected to the final polishing was evaluated for defect evaluation of the polishing liquid (60 nm or more) using ComPlus (defect inspection apparatus manufactured by AMAT).
A: The number of defects after polishing is 20 / Wf or less B: The number of defects after polishing is more than 20 / Wf, 30 / Wf or less C: The number of defects after polishing is more than 30 / Wf, 50 Pieces / Wf or less D: Number of defects after polishing exceeds 50 / Wf, 60 pieces / Wf or less E: Number of defects after polishing exceeds 60 pieces / Wf, 80 pieces / Wf or less F: Defects after polishing Number: More than 80 / Wf, 100 / Wf or less G: Number of defects after polishing exceeds 100 / Wf, 120 / Wf or less H: Number of defects after polishing exceeds 120 / Wf

[Stability evaluation over time]
Each polishing liquid was stored at 40 ° C. for 1 month. Using a particle size distribution analyzer SALD-2300 (manufactured by Shimadzu Corporation), each particle size distribution (average particle size) of the abrasive particles immediately after preparation (initial) and the abrasive particles after storage is measured to determine each average particle size, The temporal stability of the polishing liquid was evaluated based on the ratio calculated from the following formula.
Formula (6): T3 = average particle diameter of abrasive particles after storage / average particle diameter of initial abrasive particles A: T3 is 1.1 or less B: T3 is more than 1.1, 1.3 or less C: T3 is More than 1.3, 1.5 or less D: T3 exceeds 1.5

The results are shown in Tables 1 and 2.
In the table, “%” and “ppb” are both based on mass.
Further, “polishing rate ratio R1”, “polishing rate ratio R2”, and “polishing rate ratio R3” are values calculated from the following equations (3) to (5), respectively.
Formula (3):
R1 = Polishing speed of cobalt substrate with polishing liquid / Polishing speed of barrier substrate with polishing liquid (4)
R2 = Cobalt substrate polishing rate with polishing solution / Barrier substrate polishing rate with polishing solution Formula (5):
R3 = Polishing speed of cobalt substrate with polishing liquid / Polishing speed of insulating film substrate with polishing liquid Also, the “metal impurity amount” is a specific metal selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms The content of the atom with respect to the total mass of the polishing liquid is intended.
Further, “amount of metal particles” means the total amount of polishing liquid of a specific metal atom selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom contained in solid metal impurities among the above metal impurities. Intended for content relative to mass.
Further, “H ₂ O ₂ / metal impurity amount (T1)” is a value calculated from the following formula (1).
Formula (1): T1 = Content of hydrogen peroxide / Total content of specific metal atoms selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms contained in metal impurities. "ppb)" intends the content of the compound represented by the general formula (1) described above with respect to the total mass of the polishing liquid.
The polishing liquid was adjusted with water (remainder) so that the total mass was 100% by mass.

In Table 1 below, Table 1A2, Table 1B2, Table 1C2, and Table 1D2 are respectively the Examples 1A to 83A and Comparative Examples 1A to 5A shown in Table 1A1, Table 1B1, Table 1C1, and Table 1D1, respectively. The various evaluation result about polishing liquid is shown.
That is, for example, in the case of Example 1A, Table 1A2 shows various evaluations using the polishing liquid of Table 1A1. The thickness of the Co reaction layer in the polishing liquid of Example 1A is 4 nm, the dishing evaluation is 4 nm (corresponding to A), the defect evaluation is A, and the temporal stability is A. For example, when the barrier metal is TaN, the thickness of the TaN reaction layer is 0.08 nm.
In Table 2 below, Table 2A2 and Table 2A3, Table 2B2 and Table 2B3, Table 2C2 and Table 2C3, Table 2D2 and Table 2D3 are shown in Table 2A1, Table 2B1 and Table 2C1, respectively. 82B shows various evaluation results for the polishing liquids of Comparative example 1B to 3B.
That is, for example, for Example 1B, Table 2A2 and Table 2A3 show various evaluations using the polishing liquid of Table 2A1. The thickness of the Co reaction layer in the polishing liquid of Example 1B is 1 nm, dishing evaluation is 3.5 nm (corresponding to A), erosion evaluation is 8.75 nm (corresponding to C), defect evaluation is A, and stability over time is A. It is. For example, when the barrier metal is TaN, the thickness of the TaN reaction layer is 0.212 nm.

From the results of Tables 1 and 2, it was confirmed that the polishing liquids of the examples all suppressed the occurrence of dishing, erosion, and defects on the surface to be polished. It was also confirmed that the stability over time was excellent.
On the other hand, in the polishing liquids of Comparative Examples 1 to 5, dishing and defects were confirmed on the surface to be polished.

Results of Examples 1A to 83A (Table 1)
From the comparison of Examples 1A and 8A to 11A, when the content of hydrogen peroxide is 0.001 to 2.5% by mass (preferably 0.06 to 2% by mass) with respect to the total mass of the polishing liquid, It was confirmed that dishing on the polished surface was less likely to occur.
Further, from the comparison of Examples 1A and 12A to 15A, the content of the azole compound is 0.01 to 1.3% by mass (preferably 0.01 to 0.4% by mass) with respect to the total mass of the polishing liquid. %), Dishing on the surface to be polished was less likely to occur and the stability over time was excellent.
From the comparison of Examples 1A and 19A to 21A, when the ratio T2 of the average particle diameter before and after chemical mechanical polishing of colloidal silica having an association degree of 1 to 3 is 2.5 or less (preferably 2 or less), It was confirmed that defects on the polished surface were less likely to occur.
Further, in comparison with Examples 1A and 22A to 25A, when the pH of the polishing liquid is 6.5 to 8.0 (preferably 6.8 to 7.8, more preferably 6.8 to 7.2). It was confirmed that dishing and defects on the surface to be polished were less likely to occur, and the stability over time was excellent. Further, from the comparison of Examples 1A and 26A to 29A, the content of the compound represented by the general formula (1) is 1000 mass ppb or less (preferably 250 mass ppb or less, based on the total mass of the polishing liquid In the case of preferably 8 mass ppb or less), it was confirmed that dishing and defects on the surface to be polished were less likely to occur, and the stability over time was excellent.
Further, from the comparison of Examples 1A and 30A to 32A, the content of one specific metal atom selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom contained in the metal impurity is the total amount of the polishing liquid. In the case of 0.01 to 100 mass ppb (preferably 0.01 to 50 mass ppb, more preferably 0.01 to 20 mass ppb) with respect to the mass, dishing and defects on the surface to be polished more occur. It was difficult to confirm and excellent in stability over time. Further, when the specific metal atom contained in the metal particle is 0.01 to 50 mass ppb (preferably 0.01 to 8 mass ppb) with respect to the total mass of the polishing liquid, the object to be polished It was confirmed that dishing and defects on the surface were less likely to occur, and the stability over time was excellent.
Further, from the comparison of Examples 1A, 33A to 35A, 54A, and 55A, when the amino acid content is 0.8 to 4% by mass with respect to the total mass of the polishing liquid, dishing and defects on the surface to be polished are observed. It was confirmed that it was less likely to occur and was more stable over time.
Further, from the comparison between Examples 1A and 36A to 38A, it was confirmed that dishing on the surface to be polished was less likely to occur when glycine or N-methylglycine (preferably glycine) was contained as the amino acid.
Further, in comparison with Examples 1A, 57A, and 58A, when the content of colloidal silica having an association degree of 1 to 3 is 0.01 to 0.15% by mass with respect to the total mass of the polishing liquid, It was confirmed that dishing was less likely to occur.
Further, in comparison with Examples 1A and 39A to 53A, when a polishing liquid containing a compound having a benzotriazole skeleton and a compound different from a benzotriazole-based compound is applied to CMP, dishing occurs more on the surface to be polished. It was confirmed that it was difficult to do.
Further, in comparison with Examples 1A, 8A to 11A, and 30A to 32A, the polishing liquid is a specific metal selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms contained in hydrogen peroxide and metal impurities. It was confirmed that when the content ratio T1 with the atom is 30,000 to 500,000 (preferably 30,000 to 110,000, more preferably 30,000 to 80,000), dishing on the surface to be polished is less likely to occur.
From the comparison between Example 1A and 39A to 41A, it was confirmed that dishing on the polished surface was less likely to occur when 5-methylbenzotriazole was included as the compound having a benzotriazole skeleton.

Results of Examples 1B-82B (Table 2)
From the comparison between Examples 1B and 8B to 10B, when the hydrogen peroxide content is 0.1 to 1.2% by mass (preferably 0.6 to 1% by mass) with respect to the total mass of the polishing liquid In addition, dishing and erosion are less likely to occur on the surface to be polished.
Further, from the comparison between Examples 1B and 11B to 14B, the content of the azole compound is 0.12 to 3.5% by mass (preferably 0.12 to 0.8% by mass) with respect to the total mass of the polishing liquid. In the case of 0.12 to 0.5% by mass), dishing and erosion on the surface to be polished are less likely to occur, and the stability over time is excellent.
When the average particle diameter ratio T2 before and after chemical mechanical polishing of colloidal silica having an association degree of 1 to 3 is 2.5 or less (preferably 2 or less) from the comparison of Examples 1B and 18B to 20B It was confirmed that defects on the polished surface are less likely to occur.
Further, in comparison with Examples 1B and 21B to 23B, when the polishing solution has a pH of 8.2 to 9.5 (preferably 8.7 to 9.5), dishing and erosion on the surface to be polished and It was confirmed that defects are less likely to occur.
Further, from the comparison of Examples 1B and 24B to 27B, the content of the compound represented by the general formula (1) is 1000 mass ppb or less (preferably 250 mass ppb or less, based on the total mass of the polishing liquid). In the case of preferably 8 mass ppb or less), it was confirmed that dishing, erosion, and defects on the polished surface are less likely to occur, and that the stability over time is excellent.
Further, from the comparison of Examples 1B and 28B to 30B, the content of one specific metal atom selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom contained in the metal impurity is the total amount of the polishing liquid. In the case of 0.01 to 100 mass ppb with respect to mass (preferably 0.01 to 20 mass ppb), dishing, erosion and defects on the surface to be polished are less likely to occur, and the stability over time is excellent. Was confirmed. Further, when the specific metal atom contained in the metal particle is 0.01 to 50 mass ppb (preferably 0.01 to 8 mass ppb) with respect to the total mass of the polishing liquid, the object to be polished It was confirmed that dishing and erosion on the surface and defects were less likely to occur, and the stability over time was excellent.

Further, in comparison with Examples 1B and 31B to 36B, when the content of the organic acid is 0.01 to 0.3% by mass with respect to the total mass of the polishing liquid, dishing, erosion and defects on the surface to be polished It has been confirmed that is less likely to occur and is more stable over time.
Further, in comparison with Examples 1B and 37B to 39B, when the organic acid is used in combination with maleic acid and citric acid or malonic acid (preferably, maleic acid and citric acid are used in combination), the surface to be polished It was confirmed that dishing and erosion were less likely to occur and the stability over time was superior.
From the comparison of Example 1B and 40B to 42B, when benzotriazole, 5-aminobenzotriazole, or 5,6-dimethylbenzoatriazole was contained as the compound having a benzotriazole skeleton, dishing and erosion on the polished surface were observed. It was confirmed that it is less likely to occur.
Further, in comparison with Examples 1B, 40B to 48B, 52B, and 53B, a polishing liquid containing a compound having a benzotriazole skeleton and a compound different from the benzotriazole compound as an azole compound is applied to CMP. It was confirmed that dishing and erosion were less likely to occur on the polished surface.
Further, in comparison with Examples 1B, 55B, and 56B, when the content of colloidal silica having an association degree of 1 to 3 is 0.5 to 3% by mass with respect to the total mass of the polishing liquid, dishing and erosion are performed on the surface to be polished. It was confirmed that is less likely to occur.
Further, from the comparison of Examples 1B, 8B to 10B, and 28B to 30B, the polishing liquid is a specific metal selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms contained in hydrogen peroxide and metal impurities. It was confirmed that dishing and erosion were less likely to occur on the surface to be polished when the content ratio T1 with the atom was 30,000 to 500,000 (preferably 100,000 to 500,000, more preferably 250,000 to 500,000).

[Example 84A]
Example 84A was prepared in the same manner as in Example 1A, except that each component was changed as shown in Table 3. Note that Example 84A corresponds to a polishing liquid stock solution.
Further, water was used as a diluent, and the polishing liquid of Example 84A was diluted 10 times.
The pH change before and after dilution was 0.01, and it was confirmed that there was no difference in performance of the polishing liquid before and after dilution.

[Example 85A]
Example 85A was prepared in the same manner as in Example 1A, except that each component was as shown in Table 3. In addition, Example 85A corresponds to a polishing liquid stock solution.
Furthermore, the polishing liquid of Example 85A was diluted 50 times using water as a diluent.
The pH change before and after dilution was 0.1, and it was confirmed that there was no difference in performance of the polishing liquid before and after dilution.

[Example 1B (A) to Example 1B (E)]
Evaluation similar to Example 1B was performed, except that the polishing liquid of Example 1B was used and the dishing evaluation substrate and the erosion evaluation test substrate were changed to the following. The results are shown in Tables 4 to 8 as Examples 1B (A) to 1B (E), respectively.
(1) For dishing evaluation;
A substrate with a pattern of cobalt wiring (made by International SEMATECH, an insulating layer made of SiOx on a silicon substrate having a thickness of 5000 mm, and then patterned with a “SEMATECH 854” mask (L / S = 10 μm / 10 μm) A test substrate in which a barrier metal layer (barrier metal: TaN, Ti, TiN, Ru, or Mn) having a thickness of 100 mm and a cobalt layer having a thickness of 7500 are sequentially stacked.
(2) For erosion evaluation;
A substrate with a pattern of cobalt wiring (made by International SEMATECH, an insulating layer made of SiOx on a silicon substrate having a thickness of 5000 mm, and then patterned with a “SEMATECH 854” mask (L / S = 9 μm / 1 μm) A test substrate in which a barrier metal layer (barrier metal: TaN, Ti, TiN, Ru, or Mn) having a thickness of 100 mm and a cobalt layer having a thickness of 7500 are sequentially stacked.

As shown in Tables 4 to 8, the polishing liquid of Example 1B caused dishing and erosion on the substrate having any barrier metal layer of Ta, TaN, Ti, TiN, Ru, and Mn. It was confirmed that it was suppressed.

[Example 83B]
Example 83B was prepared in the same manner as in Example 1B except that each component was changed as shown in Table 9. Note that Example 83B corresponds to a polishing liquid stock solution.
Further, water was used as a diluent, and the polishing solution of Example 83B was diluted twice.
The pH change before and after dilution was 0.1, and it was confirmed that there was no difference in performance of the polishing liquid before and after dilution.

Claims

Colloidal silica with a degree of association of 1 to 3,
An organic acid,
An azole compound,
Hydrogen peroxide, and a polishing liquid used for chemical mechanical polishing of the cobalt-containing layer,
A polishing liquid in which a reaction layer having a thickness of 0.5 to 20 nm containing cobalt atoms is formed on the cobalt substrate when the polishing liquid and the cobalt substrate are brought into contact with each other for 24 hours.
The content of the colloidal silica having an association degree of 1 to 3 is 0.01 to 1% by mass with respect to the total mass of the polishing liquid.
As the organic acid, containing an amino acid,
The azole compound contains a benzotriazole compound and an azole compound different from the benzotriazole compound,
pH is 6.5 to 8.0,
When the polishing liquid is brought into contact with a barrier substrate made of any one metal selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn for 24 hours, the metal The polishing liquid according to claim 1, wherein a reaction layer containing atoms and having a thickness of 0.01 to 5 nm is formed.
The polishing liquid according to claim 2, wherein the polishing rate ratio R1 calculated from the following formula (3) is 250 to 2500.
Formula (3):
R1 = Cobalt substrate polishing rate with the polishing liquid / Barrier substrate polishing rate with the polishing liquid
The content of the colloidal silica having an association degree of 1 to 3 is 0.5 to 5% by mass with respect to the total mass of the polishing liquid,
The azole compound contains a benzotriazole compound and an azole compound different from the benzotriazole compound,
pH is 8.0-10.5,
When the polishing liquid is brought into contact with a barrier substrate made of any one metal selected from the group consisting of Ta, TaN, Ti, TiN, Ru, and Mn for 24 hours, atoms of the metal on the barrier substrate A reaction layer containing 0.01 to 5 nm in thickness is formed,
When the polishing liquid and the insulating film substrate made of any one of inorganic components selected from the group consisting of SiOx and SiOC are contacted for 24 hours, the insulating film substrate has a thickness of 0.01 to 10 nm containing silicon atoms. The polishing liquid according to claim 1, wherein the reaction layer is formed.
The organic acid is maleic acid, fumaric acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, merophanic acid, Is at least one selected from the group consisting of planitic acid, pyromellitic acid, mellitic acid, diphenic acid, citric acid, succinic acid, malic acid, malonic acid, and anthranilic acid,
The polishing liquid according to claim 4, wherein the content of the organic acid is 0.01 to 0.3 mass% with respect to the total mass of the polishing liquid.
The polishing rate ratio R2 calculated from the following formula (4) is 0.01 to 2.0, and the polishing rate ratio R3 calculated from the following formula (5) is 0.05 to 2.0. The polishing liquid according to claim 4 or 5.
Formula (4):
R2 = Cobalt substrate polishing rate with the polishing liquid / Barrier substrate polishing rate with the polishing liquid Formula (5):
R3 = Cobalt substrate polishing rate with the polishing liquid / Insulating film substrate polishing rate with the polishing liquid
The polishing liquid according to any one of Claims 1 to 6, wherein the hydrogen peroxide content is 0.001 to 5 mass%.
Furthermore, containing metal impurities containing metal atoms,
The metal impurity contains at least one specific metal atom selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom,
When the specific metal atom is one selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom, the content of the specific metal atom is 0.01 to 100 mass ppb,
When the specific metal atom is two or more selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom, the content of each specific metal atom is 0 with respect to the total mass of the polishing liquid. The polishing liquid according to any one of claims 1 to 7, wherein the polishing liquid has a mass of 0.01 to 100 mass ppb.
The metal impurity contains metal particles containing at least one specific metal atom selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom,
When the specific metal atom contained in the metal particle is one selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom, the content of the specific metal atom contained in the metal particle is , And 0.01 to 50 mass ppb with respect to the total mass of the polishing liquid,
When the specific metal atom contained in the metal particle is two or more selected from the group consisting of Fe atom, Cu atom, Ag atom, and Zn atom, each of the specific metal atom contained in the metal particle The polishing liquid according to claim 8, wherein the content is 0.01 to 50 mass ppb with respect to the total mass of the polishing liquid.
The polishing liquid according to claim 8 or 9, wherein the content ratio T1 calculated from the following formula (1) is 30,000 to 500,000.
Formula (1): T1 = content of hydrogen peroxide / total content of specific metal atoms selected from the group consisting of Fe atoms, Cu atoms, Ag atoms, and Zn atoms contained in the metal impurities
Furthermore, it contains a compound represented by the following general formula (1), and the compound represented by the general formula (1) is 0.00001 to 1000 mass ppb with respect to the total mass of the polishing liquid. The polishing liquid according to any one of 1 to 10.
General formula (1):
N (R 1 ) (R 2 ) (R 3 )
In general formula (1), R 1 to R 3 each independently represents a hydrogen atom or an alkyl group.
The polishing liquid according to any one of claims 1 to 11, further comprising an organic solvent, wherein the content of the organic solvent is 0.01 to 20% by mass relative to the total mass of the polishing liquid.
Further, N-cocoyl sarcosinate, N-lauroyl sarcosinate, N-stearoyl sarcosinate, N-oleoyl sarcosinate, N-myristoyl sarcosinate, N-lauroyl glycine, N-myristoyl glycine, N- From the group consisting of palmitoyl glycine, N-lauroyl glutamic acid, N-cocoyl glutamic acid, potassium N-cocoyl glutamate, potassium N-lauroyl sarcosinate, N-lauroyl alaninate, N-myristoyl alaninate, and potassium N-cocoyl alaninate The polishing according to any one of claims 1 to 12, comprising at least one selected compound, wherein the total content of the compound is 0.001 to 5 mass% with respect to the total mass of the polishing liquid. liquid.
The azole compound contains a benzotriazole compound and one or more selected from the group consisting of 1,2,4-triazole compounds, pyrazole compounds, and imidazole compounds. 14. The polishing liquid according to any one of 2 to 13.
The average particle diameter ratio T2 before and after chemical mechanical polishing of the colloidal silica having the association degree of 1 to 3 calculated from the following formula (2) is 1 to 5. The polishing liquid according to item.
Formula (2):
T2 = average particle diameter after chemical mechanical polishing / average particle diameter before chemical mechanical polishing
16. The polishing liquid stock solution containing colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, and hydrogen peroxide is mixed with water, according to any one of claims 1 to 15. The manufacturing method of polishing liquid containing the dilution process which obtains the polishing liquid of description.
A colloidal silica having an association degree of 1 to 3, an organic acid, an azole compound, and hydrogen peroxide;
A polishing liquid stock solution used by diluting 2 to 50 times to prepare the polishing liquid according to any one of claims 1 to 15.
The polishing liquid stock solution according to claim 17, wherein the pH change before and after dilution is 0.01 to less than 1 when diluted 2 to 50 times with water.
A polishing liquid stock solution container comprising: the polishing liquid stock solution according to claim 17 or 18; and a container formed of a metal material containing no iron and containing the polishing liquid stock solution.
The surface to be polished is brought into contact with the polishing pad while supplying the polishing liquid according to any one of claims 1 to 15 to a polishing pad attached to a polishing surface plate, and the object to be polished And a chemical mechanical polishing method comprising a step of relatively moving the polishing pad to polish the surface to be polished to obtain a polished object to be polished.
21. The chemical mechanical polishing method according to claim 20, wherein the object to be polished contains a cobalt-containing layer made of at least one selected from the group consisting of cobalt and a cobalt alloy.