KR102298238B1 - Polishing liquid, and chemical mechanical polishing method - Google Patents

Abstract

An object of the present invention is to provide a polishing liquid in which the abrasive grains contained in the polishing liquid are less likely to aggregate, and defects are unlikely to occur on the surface to be polished even when applied to CMP. Moreover, it is also made into a subject to provide the chemical mechanical polishing method. The polishing liquid of the present invention is a polishing liquid for chemical mechanical polishing containing abrasive grains, an organic acid, and an alcohol A, wherein the alcohol A is at least one selected from the group consisting of methanol, ethanol, 1-propanol, and isopropanol; Content of alcohol A is 1.0-800 mass ppm in the total mass of polishing liquid.

Description

Polishing liquid, and chemical mechanical polishing method

The present invention relates to a polishing liquid and a chemical mechanical polishing method.

In the manufacture of a large-scale integrated circuit (LSI), a chemical mechanical polishing (CMP) method is used for planarization of a bare wafer, planarization of an interlayer insulating film, formation of a metal plug, and formation of buried wiring. is becoming

As a polishing liquid used for CMP, for example, in Patent Document 1, "It contains alcohol, abrasive grains and water whose solubility in water is 0.5 to 8% by weight at a liquid temperature of 25 degrees. abrasive liquid."

Japanese Patent Laid-Open No. 2004-074175

When the present inventor studied the polishing liquid described in Patent Document 1, when the polishing liquid was stored, it was found that there was a problem in that the abrasive grains contained in the polishing liquid tend to aggregate. In addition, it has also been found that when the polishing liquid is applied to CMP, there is a problem in that the surface to be polished of the object to be polished is prone to defects.

Therefore, the present invention provides a polishing liquid in which the abrasive grains are less likely to aggregate (in other words, "having excellent stability over time") and in which defects (in other words, "scratch") on the surface to be polished do not easily occur even when applied to CMP. The task is to provide

Another object of the present invention is to provide a chemical mechanical polishing method.

As a result of intensive studies to achieve the above object, the present inventors have found that a polishing liquid for chemical mechanical polishing containing abrasive grains, an organic acid, and a predetermined alcohol A, wherein the alcohol A content is within a predetermined range, can solve the above problems. Discovery of solvable problems, the present invention was completed.

That is, it discovered that the said subject could be achieved with the following structures.

[1] A polishing liquid for chemical mechanical polishing containing abrasive grains, an organic acid, and an alcohol A, wherein the alcohol A is at least one selected from the group consisting of methanol, ethanol, 1-propanol, and isopropanol, and the content of the alcohol A The polishing liquid, which is 1.0 to 800 mass ppm in the total mass of the polishing liquid.

[2] The polishing liquid according to [1], wherein the content by mass ratio of the alcohol A to the organic acid is 0.001 to 0.05.

[3] The polishing liquid according to [1] or [2], further comprising a charge control agent, wherein the charge control agent contains at least one selected from the group consisting of inorganic acids, ammonium salts of organic acids, and ammonium salts of inorganic acids.

[4] The polishing liquid according to [3], wherein the content of the charge modifier is 10-1000 mass ppm with respect to the total mass of the polishing liquid.

[5] The polishing liquid according to [3] or [4], wherein the content ratio of the alcohol A to the charge control agent is 0.1 to 50.

[6] The polishing liquid according to any one of [1] to [5], wherein the organic acid is an amino acid.

[7] Amino acids, glycine, alanine, arginine, isoleucine, leucine, valine, phenylalanine, asparagine, glutamine, lysine, histidine, proline, tryptophan, aspartic acid, glutamic acid, serine, threonine, tyrosine, cysteine, methionine The polishing liquid according to [6], which is at least one selected from the group consisting of , and N-methylglycine.

[8] The polishing liquid according to [6] or [7], comprising two or more amino acids.

[9] The polishing liquid according to any one of [1] to [8], wherein the polishing liquid has a pH of 5.0 to 8.0.

[10] The polishing liquid according to any one of [1] to [9], further comprising an oxidizing agent.

[11] The polishing liquid according to [10], containing two or more oxidizing agents.

[12] The polishing liquid according to any one of [1] to [11], further comprising two or more azole compounds.

[13] The polishing liquid according to [12], wherein the two or more azole compounds contain a benzotriazole compound and an azole compound different from the benzotriazole compound.

[14] The polishing liquid according to [13], wherein the azole compound different from the benzotriazole compound is at least one selected from the group consisting of a 1,2,4-triazole compound, a pyrazole compound, and an imidazole compound.

[15] The polishing liquid according to any one of [1] to [14], wherein the content of the organic acid is 1.0 to 20 mass % with respect to the total mass of the polishing liquid.

[16] The polishing liquid according to any one of [1] to [15], wherein the abrasive grains are colloidal silica.

[17] While supplying the polishing liquid according to any one of [1] to [16] to the polishing pad mounted on the polishing platen, the surface to be polished of the object to be polished is brought into contact with the polishing pad, and the polishing body and the polishing pad are A chemical mechanical polishing method comprising the step of polishing a surface to be polished by moving relatively to obtain a polished object.

[18] The chemical mechanical polishing method according to [17], wherein the object to be polished contains at least one layer selected from the group consisting of copper, copper alloy, tungsten, tungsten alloy, silicon nitride, and polysilicon.

ADVANTAGE OF THE INVENTION According to this invention, it can provide the grinding|polishing liquid which has excellent stability with time, and is hard to generate|occur|produce a defect in the to-be-polished surface (hereinafter also referred to as "having the effect of the present invention") even when applied to CMP.

Moreover, according to this invention, the chemical mechanical polishing method can also be provided.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on embodiment.

In addition, description of the structural element described below is made based on embodiment of this invention, and this invention is not limited to such embodiment.

In addition, in this specification, the numerical range shown using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

[Abrasive Fluid]

A polishing liquid according to an embodiment of the present invention is a polishing liquid for chemical mechanical polishing containing abrasive grains, an organic acid, and an alcohol A, wherein the alcohol A is selected from the group consisting of methanol, ethanol, 1-propanol, and isopropanol It is at least 1 type, and it is a polishing liquid whose content of alcohol A is 1.0-800 mass ppm in the total mass of a polishing liquid. In addition, in this specification, ppm intends parts per million (parts per million).

[Alcohol A (Alc)]

As one of the characteristic points of the said polishing liquid, the point that content of alcohol A is 1.0-800 mass ppm with respect to the total mass of a polishing liquid is mentioned.

If the content of alcohol A exceeds the upper limit, the absolute value of the zeta potential of the surface of the abrasive grains (particularly the surface of colloidal silica) decreases, the abrasive grains tend to aggregate in the polishing liquid during storage, and it is estimated that the stability with time decreases.

On the other hand, when the content of the alcohol A is less than the lower limit, when the polishing liquid is applied to CMP, defects are likely to occur on the polished surface of the object to be polished.

Content of the said alcohol A is 1.0-800 mass ppm with respect to the total mass of polishing liquid, 1.0-750 mass ppm is preferable, and its 10-500 mass ppm is more preferable.

The alcohol A is at least one selected from the group consisting of methanol, ethanol, 1-propanol, and isopropanol.

In addition, as alcohol A, 1 type may be used individually and 2 or more types may be used together. When using 2 or more types of alcohol A together, total content of 2 or more types of alcohol A is 1.0-800 mass ppm, The suitable range is as above.

In addition, in this specification, the alcohol A content in a polishing liquid intends content measured by the following method.

The measurement of the alcohol A content in the polishing liquid is performed using gas chromatography. The gas chromatography measurement conditions are as follows. In addition, when the mixing ratio of each component of the polishing liquid is clear, the alcohol A content can be obtained from the alcohol A mixing ratio with respect to the total mass of the polishing liquid, and the above measurement can be substituted.

・Gas chromatography: 7890 series manufactured by Agilent Technologies

・Temperature increase conditions: Initial temperature of 40°C, temperature increase to 250°C at a temperature increase rate of 10°C/min.

Capillary column: Agilent J&W GC column DB-WAX, 60 m × 0.25 mm (inner diameter), film thickness: 0.25 μm

·Carrier gas flow rate: Helium 1.0mL/min

·Inlet temperature: 250℃

・Hydrogen salt ion detector temperature: 300℃

(pH)

Although the pH of the polishing liquid is not particularly limited, it is usually preferably 1.0 to 14.0. Especially, 5.0-8.0 are more preferable.

If the pH is 5.0 or higher, a polishing liquid having more excellent stability with time is obtained, and even when the polishing liquid is applied to CMP, defects are more unlikely to occur on the surface to be polished. Although the mechanism by which this effect is obtained is not necessarily clear, for example, since the isoelectric point of the zeta potential of the surface of colloidal silica is around pH 4.0, by adjusting the pH of the polishing liquid within the above range larger than the isoelectric point, the abrasive grains are This inventor guesses that it became more difficult to aggregate.

On the other hand, if the pH is 8.0 or less, dishing is more unlikely to occur on the polished surface of the object to be polished when the polishing liquid is applied to CMP.

[Abrasive grain (A)]

The said polishing liquid contains an abrasive grain. It does not restrict|limit especially as an abrasive grain, A well-known abrasive grain can be used.

Examples of the abrasive grains include inorganic abrasive grains such as silica, alumina, zirconia, ceria, titania, germania, and silicon carbide; and organic material abrasive grains, such as polystyrene, polyacryl, and polyvinyl chloride. Among them, silica particles are preferable as the abrasive grains from the viewpoints of excellent dispersion stability in the polishing liquid and a small number of abrasive scratches (scratches) generated by CMP.

It does not restrict|limit especially as a silica particle, For example, precipitated silica, fumed silica, colloidal silica, etc. are mentioned. Especially, colloidal silica is more preferable.

The average primary particle diameter of the abrasive grains is not particularly limited, but is preferably 1 to 100 nm from the viewpoint of the polishing liquid having more excellent dispersion stability. In addition, the said average primary particle diameter can be confirmed with the catalog etc. of a manufacturing company.

As a commercial item of the said abrasive grain, PL-1, PL-2, PL-3, PL-7, and PL-10H etc. (all are brand names, the Fuso Chemical Co., Ltd. make) are mentioned, for example as colloidal silica.

The content of the abrasive is not particularly limited, and is preferably 0.01 mass % or more, more preferably 0.1 mass % or more, more preferably 10 mass % or less, and more preferably 5 mass % or less with respect to the total mass of the polishing liquid. Within the above range, a more excellent polishing rate is obtained when the polishing liquid is applied to CMP.

In addition, an abrasive may be used individually by 1 type, and may use 2 or more types together. When using two or more types of abrasive grains together, it is preferable that total content exists in the said range.

The content of the abrasive grain preferably satisfies the following relationship with the content of the alcohol A. That is, the mass ratio of the alcohol A content to the abrasive grain content (alcohol A content/abrasive grain content; also referred to as "Alc/A" ratio) is preferably 0.0001 to 1.5, more preferably 0.01 to 0.08, 0.1-0.7 are more preferable.

When the Alc/A ratio is 0.1 to 0.7 and the polishing liquid is applied to CMP, a more excellent polishing rate is obtained.

[Organic Acid (B)]

The polishing liquid contains an organic acid. The organic acid is a compound different from the oxidizing agent and charge adjusting agent described later, and has an effect of promoting metal oxidation, adjusting the pH of the polishing liquid, and serving as a buffer.

As the organic acid, a water-soluble organic acid is preferable.

It does not restrict|limit especially as an organic acid, A well-known organic acid can be used.

Examples of the organic acid include 1-hydroxyethylidene-1,1-diphosphonic acid (hereinafter also referred to as “HEDP”), diethylenetriamine pentaacetic acid (hereinafter also referred to as “DTPA”), 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-methyl Hexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid , tartaric acid, citric acid, lactic acid, hydroxyethyliminodiacetic acid, and iminodiacetic acid.

As an organic acid, an amino acid is more preferable at the point which has more outstanding water solubility.

It does not restrict|limit especially as an amino acid, A well-known amino acid can be used.

Examples of the amino acid include glycine, alanine (α-alanine and/or β-alanine), arginine, isoleucine, leucine, valine, phenylalanine, asparagine, glutamine, lysine, histidine, proline, tryptophan, aspartic acid. , glutamic acid, serine, threonine, tyrosine, cysteine, methionine, and N-methylglycine.

Among them, since the polishing liquid has more excellent effects of the present invention, the amino acid is preferably glycine, α-alanine, β-alanine, L-aspartic acid, or methylglycine (N-methylglycine), and glycine , and/or methylglycine is more preferable.

Moreover, an amino acid may be used individually by 1 type, and may use 2 or more types together. When using two or more types of amino acids together, it is preferable that total content exists in the said range.

Among them, it is preferable that the polishing liquid contains two or more kinds of amino acids from the viewpoint of obtaining a polishing liquid having the superior effect of the present invention.

There is no restriction|limiting in particular as 2 or more types of amino acids, Combination of the said amino acid can be used. In particular, when the polishing liquid is applied to CMP, a more excellent polishing rate is obtained, and dishing is less likely to occur on the surface to be polished. As two or more amino acids, glycine, alanine, alanine and N -Methylglycine, a combination of glycine and N-methylglycine is preferable.

The content of the organic acid is not particularly limited, with respect to the total mass of the polishing liquid, preferably 0.1 mass % or more, more preferably 0.5 mass % or more, still more preferably 1.0 mass % or more, and preferably 50 mass % or less. , 25 mass % or less is more preferable, 20 mass % or less is still more preferable, and 10 mass % or less is especially preferable.

When the content of the organic acid is 0.1% by mass or more and the polishing liquid is applied to CMP, a more excellent polishing rate is obtained. Moreover, when the content of the organic acid is 50% by mass or less and the polishing liquid is applied to CMP, dishing is less likely to occur on the surface to be polished.

If the content of the organic acid is 1.0 to 20 mass % with respect to the total mass of the polishing liquid, a polishing liquid having more excellent effects of the present invention can be obtained.

In addition, an organic acid may be used individually by 1 type, and may use 2 or more types together. When using together 2 or more types of organic acids, it is preferable that total content exists in the said range.

It is preferable that content of an organic acid satisfy|fills the following relationship with content of the said alcohol A. That is, the mass ratio (alcohol A content/organic acid content; also referred to as "Alc/B" ratio) of the content of the alcohol A to the content of the organic acid is preferably 0.0001 to 0.2, more preferably 0.0006 to 0.1, 0.001-0.05 are more preferable.

When the Alc/B ratio is 0.001 to 0.05, a more excellent polishing rate is obtained when the polishing liquid is applied to CMP.

[optional ingredient]

The polishing liquid may contain components other than the above as optional components. Hereinafter, optional components will be described.

<Anticorrosive (C)>

The said polishing liquid may contain an anticorrosive agent.

It is preferable that the anticorrosive agent has an action of adsorbing on the surface to be polished of the object to be polished, forming a film, and controlling corrosion of the metal. It does not restrict|limit especially as an anticorrosive, Although a well-known anticorrosive can be used, Especially, an azole compound is preferable.

(azole compounds)

In the present specification, the azole compound refers to a compound containing a hetero five-membered ring containing one or more nitrogen atoms, and the number of nitrogen atoms is preferably 1-4. Moreover, the azole compound may contain atoms other than a nitrogen atom as a hetero atom.

Moreover, the said derivative intends the compound which has a substituent which the said hetero five-membered ring may contain.

Examples of the azole compound include pyrrole skeleton, imidazole skeleton, pyrazole skeleton, isothiazole skeleton, isoxazole skeleton, triazole skeleton, tetrazole skeleton, imidazole skeleton, thiazole skeleton, oxazole skeleton, The compound etc. which have an isoxazole skeleton, a thiadiazole skeleton, an oxadiazole skeleton, and a tetrazole skeleton are mentioned.

As said azole compound, the azole compound which further contains the polycyclic structure containing the condensed ring in said skeleton may be sufficient. Examples of the azole compound containing the polycyclic structure include indole skeleton, purine skeleton, indazole skeleton, benzimidazole skeleton, carbazole skeleton, benzoxazole skeleton, benzothiazole skeleton, benzothiazole skeleton, and The compound etc. which contain a naphthoimidazole skeleton are mentioned.

Although it does not restrict|limit especially as a substituent which the azole compound may contain, For example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a straight-chain, branched or cyclic alkyl group, It may be a polycyclic alkyl group such as a cycloalkyl group or may include an active metaphosphorus group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regardless of the position of substitution), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group , heterocyclic oxycarbonyl group, carbamoyl group (as the carbamoyl group having a substituent, for example, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoyl group carbamoyl group, thiocarbamoyl group, and N-sulfamoylcarbamoyl group), carbazoyl group, carboxyl group or a salt thereof, oxalyl group, oxamoyl group, cyano group, carbonimidoyl group, A formyl group, a hydroxy group, an alkoxy group (including a group containing an ethyleneoxy group or a propyleneoxy group as a repeating unit), an aryloxy group, a heterocyclic oxy group, an acyloxy group, a carbonyloxy group, a carbamoyloxy group, a sulfonyloxy group Group, amino group, acylamino group, sulfonamide group, ureido group, thioureido group, N-hydroxyureido group, imide group, carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazi No group, ammono group, oxamoylamino group, N- (alkyl or aryl) sulfonylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, containing a quaternized nitrogen atom Heterocyclic group (for example, pyridini group, imidazoli group, quinolini group, and isoquinolini group are mentioned), isocyano group, imino group, mercapto group, (alkyl, aryl, or hetero Ring) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or a salt thereof, sulfamoyl group (sulfamoyl group having a substituent) Examples thereof include N-acylsulfamoyl group and N-sulfonylsulfamoyl group) or salts thereof, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, and silyl group. and the like.

Among them, 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, may be a polycyclic alkyl group such as a bicycloalkyl group, ), an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group (regardless of the position of substitution) is preferable.

In addition, here, "active metaphosphorus group" means metaphosphorus group substituted with two electron withdrawing groups. The "electron withdrawing group" means, 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, and a nitro group. group, or a carbonimidoyl group. Moreover, two electron withdrawing groups may mutually couple|bond and take a cyclic structure. In addition, "salt" refers to cations such as alkali metals, alkaline earth metals, and heavy metals; Organic cations, such as an ammonium ion and a phosphonium ion, are intended.

Specific examples of the azole compound include 5-methylbenzotriazole, 5-aminobenzotriazole, benzotriazole, 5,6-dimethylbenzotriazole, 3-amino-1,2,4-triazole, 1 ,2,4-triazole, 3,5-dimethylpyrazole, pyrazole, imidazole, etc. are mentioned.

As content of an azole compound, 0.001-1.6 mass % is preferable with respect to the total mass of a polishing liquid.

In addition, an azole compound may be used individually by 1 type, and may use 2 or more types together. When using together 2 or more types of azole compounds, it is preferable that total content exists in the said range.

Especially, it is preferable to use 2 or more types of azole compounds together at the point from which the polishing liquid which has the more excellent effect of this invention is obtained. In addition, as each aspect of 2 or more types of azole compounds, it is the same as that of said azole compound.

As two or more types of azole compounds, a benzotriazole compound (compound containing a benzotriazole skeleton) and a compound different from a benzotriazole compound (benzotriazole compounds containing no skeleton).

Although it does not restrict|limit especially as said compound which does not contain a benzotriazole skeleton, A 1,2,4-triazole compound, a pyrazole compound, and an imidazole compound from the point which the polishing liquid which has the more excellent effect of this invention is obtained. It is preferable that it is at least 1 sort(s) selected from the group which consists of.

As content of an anticorrosive agent (C), 0.001-1.6 mass % is preferable with respect to the total mass of a polishing liquid.

In addition, an anticorrosive agent (C) may be used individually by 1 type, and may use 2 or more types together. When using together 2 or more types of anticorrosive agents (C), it is preferable that total content exists in the said range.

It is preferable that content of an anticorrosive agent (C) satisfy|fills the following relationship with content of the said alcohol A. That is, the mass ratio of the content of the alcohol A to the content of the anticorrosive agent (alcohol A content/content of the anticorrosive agent; also referred to as "Alc/C" ratio) is preferably 0.004 or more, and more preferably 0.0045 or more, 0.01 or more are more preferable, 0.03 or more are especially preferable, 0.04 or more are most preferable, 30 or less are preferable, 25 or less are more preferable, 5 or less are more preferable.

When the Alc/C ratio is 0.01 or more, a more excellent polishing rate is obtained when the polishing liquid is applied to CMP. In addition, when the Alc/C ratio is 0.04 or more, dishing is less likely to occur on the polished surface of the object to be polished when the polishing liquid is applied to CMP.

On the other hand, when the Alc/C ratio is 5 or less, dishing is less likely to occur on the polished surface of the object to be polished when the polishing liquid is applied to CMP.

<Oxidizing agent (D)>

The polishing liquid may contain an oxidizing agent. It does not restrict|limit especially as an oxidizing agent, A well-known oxidizing agent can be used.

Examples of the oxidizing agent include hydrogen peroxide, peroxide, nitric acid, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, dichromate, permanganate, ozone water, silver. (II) salt, iron (III) salt, etc. are mentioned, Hydrogen peroxide is more preferable. An oxidizing agent may be used individually by 1 type, and may use 2 or more types together.

Among them, when applied to CMP of a substrate (object to be polished) containing at least one layer selected from the group consisting of tungsten and a tungsten alloy, a polishing liquid having more excellent effects of the present invention is obtained. It is preferable to use 2 or more types together.

When using two or more types of oxidizing agents together, it is preferable to use together the 1st oxidizing agent with a higher oxidation-reduction potential, and the 2nd oxidizing agent (G) with a lower oxidation-reduction potential.

As a 1st oxidizing agent, at least 1 sort(s) chosen from the group which consists of hydrogen peroxide and a peroxide among the said oxidizing agents is preferable, for example, and hydrogen peroxide is more preferable.

As the second oxidizing agent, for example, among the above oxidizing agents, an iron (III) salt is preferable, and at least one selected from the group consisting of iron nitrate, iron phosphate, iron sulfate, and potassium ferricyanide is more preferable, and nitric acid Iron (Fe(NO ₃ ) ₃ ) is more preferred.

Although it does not restrict|limit especially as content of an oxidizing agent, 0.1-9.0 mass % is preferable with respect to the total mass of a polishing liquid.

When the content of the oxidizing agent is 0.1% by mass or more, a more excellent polishing rate is obtained when the polishing liquid is applied to CMP.

When the content of the oxidizing agent is 9.0% by mass or less, dishing is less likely to occur on the surface to be polished when the polishing liquid is applied to CMP.

Moreover, when using together 2 or more types of oxidizing agents, it is preferable that total content exists in the said range.

It is preferable that content of an oxidizing agent satisfy|fills the following relationship with content of the said alcohol A. That is, the mass ratio of the content of the alcohol A to the content of the oxidizing agent (the content of the alcohol A/the content of the oxidizing agent; also referred to as “Alc/D” ratio) is preferably 0.000.5 or more, and more preferably 0.005 or more, , 0.04 or more are more preferable, 0.09 or less are preferable, and 0.07 or less are more preferable.

When the Alc/D ratio is 0.005 or more, a more excellent polishing rate is obtained when the polishing liquid is applied to CMP. Further, when the Alc/D ratio is 0.04 or more, dishing is more unlikely to occur on the polished surface of the object to be polished when the polishing liquid is applied to CMP. In addition, when the Alc/D ratio is 0.07 or less, when the polishing liquid is applied to CMP, a more excellent polishing rate is obtained.

Moreover, when using a 1st oxidizing agent and a 2nd oxidizing agent together, it is preferable that content of a 2nd oxidizing agent satisfy|fills the following relationship with content of the said alcohol A. That is, as for the mass ratio of content of the said alcohol A with respect to content of a 2nd oxidizing agent (content of alcohol A/content of a 2nd oxidizing agent; also referred to as "Alc/G" ratio), 0.1-20 are preferable.

<Charge modifier (E)>

The polishing liquid may contain a charge control agent. It does not restrict|limit especially as a charge control agent, A well-known charge control agent can be used. The charge adjusting agent has an effect of adjusting the pH of the polishing liquid to the above range and/or adjusting the ionic strength of the polishing liquid to a desired range.

As a charge modifier, an acid, an alkali, a salt compound, etc. are mentioned, for example. Among them, from the viewpoint of obtaining a polishing liquid having more excellent effects of the present invention, the charge control agent preferably contains at least one selected from the group consisting of inorganic acids, ammonium salts of organic acids, and ammonium salts of inorganic acids.

Examples of the inorganic acid include sulfuric acid, hydrochloric acid, and nitric acid.

Moreover, as an ammonium salt of an organic acid, ammonium benzoate, ammonium citrate, etc. are mentioned, for example.

Moreover, as an ammonium salt of an inorganic acid, ammonium sulfate, ammonium hydrochloride, ammonium nitrate, etc. are mentioned, for example.

Although it does not restrict|limit especially as content of a charge modifier, 0.5 mass ppm or more is preferable with respect to the total mass of polishing liquid, 1 mass ppm or more is more preferable, 10 mass ppm or more is still more preferable, 2 mass % or less is preferable. and 1200 mass ppm or less is more preferable.

If the content of the charge control agent is 10 mass ppm or more, even when the polishing liquid is applied to CMP, defects are less likely to occur on the surface to be polished.

In addition, when the content of the charge modifier is 1000 ppm or less, the polishing liquid has more excellent stability with time, and when the polishing liquid is applied to CMP, an excellent polishing rate is obtained, and further, dishing is more difficult on the polished surface of the object to be polished. difficult to occur

In addition, a charge modifier may be used individually by 1 type, and may use 2 or more types together. When using together 2 or more types of charge modifiers, it is preferable that total content exists in the said range.

It is preferable that content of a charge modifier satisfy|fills the following relationship with content of the said alcohol A. That is, the mass ratio of the content of the alcohol A to the content of the charge modifier (ratio of the content of alcohol A/content of the charge modifier; also referred to as "Alc/E" ratio) is preferably 0.005 or more, and more than 0.1 or more It is preferable, 500 or less are preferable, 50 or less are more preferable, and less than 5 are more preferable.

When the Alc/E ratio is 0.1 or more, a polishing liquid having better stability with time is obtained, and when the polishing liquid is applied to CMP, a more excellent polishing rate is obtained, and dishing occurs more on the polished surface of the object to be polished. hard to do

In addition, when the Alc/E ratio is 50 or less, defects are less likely to occur on the surface to be polished even when the polishing liquid is applied to CMP.

Moreover, when Alc/E ratio is less than 5, the more excellent effect of this invention is acquired.

<Surfactant (F)>

The polishing liquid may contain a surfactant. The surfactant has an effect of lowering the contact angle of the polishing liquid with the surface to be polished, and the polishing liquid tends to wet and diffuse on the surface to be polished.

It does not restrict|limit especially as surfactant, A well-known surfactant selected from the group which consists of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, etc. can be used.

Examples of the anionic surfactant include carboxylate and sulfonic acid salts such as alkylbenzenesulfonic acid, sulfuric acid ester salts, and phosphoric acid ester salts.

Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium chlorides, benzethonium chlorides, pyridinium salts, and imidazolinium salts.

Examples of the amphoteric surfactant include carboxybetaine type, aminocarboxylate, imidazolinium betaine, lecithin, and alkylamine oxide.

Examples of the nonionic surfactant include an ether type, an ether ester type, an ester type, a nitrogen-containing type, a glycol type, a fluorine type surfactant, and a silicone type surfactant.

Although it does not restrict|limit especially as content of surfactant, 0.00001-2.0 mass % is preferable with respect to the total mass of polishing liquid, 0.0001-1.0 mass % is more preferable, 0.001-0.1 mass % is still more preferable.

When the content of the surfactant is in the range of 0.0001 to 1.0% by mass, a polishing liquid having more excellent effects of the present invention can be obtained.

Moreover, surfactant may be used individually by 1 type, and may use 2 or more types together. When using 2 or more types of surfactant together, it is preferable that total content exists in the said range.

It is preferable that content of surfactant satisfy|fills the following relationship with content of the said alcohol A. That is, the mass ratio of the content of the alcohol A to the content of the surfactant (the content of the alcohol A/the content of the surfactant; also referred to as the “Alc/F” ratio) is preferably 0.001 to 100, and more than 0.002 to 80 Preferably, 0.005-50 are more preferable.

When the Alc/F ratio is within the above range, a polishing liquid having more excellent defect performance is obtained.

<Hydrophilic polymer>

The polishing liquid may contain a hydrophilic polymer (hereinafter also referred to as "water-soluble polymer").

Examples of the hydrophilic polymer include polysaccharides such as polyglycols such as polyethylene glycol, alkyl ethers of polyglycols, polyvinyl alcohol A, polyvinylpyrrolidone, alginic acid, polymethacrylic acid, and carboxylic acid-containing polymers such as polyacrylic acid, polyacrylamide, polymethacrylamide, and polyethyleneimine. As a specific example of such a hydrophilic polymer, the water-soluble polymer described in Unexamined-Japanese-Patent No. 2009-088243 Paragraph 0042-0044, and Unexamined-Japanese-Patent No. 2007-194261 Paragraph 0026 is mentioned.

The hydrophilic polymer is preferably a water-soluble polymer selected from polyacrylamide, polymethacrylamide, polyethyleneimine, and polyvinylpyrrolidone. As polyacrylamide or polymethacrylamide, those having a hydroxyalkyl group on the nitrogen atom (for example, N-(2-hydroxyethyl)acrylamide polymer, etc.) or those having a substituent having a polyalkyleneoxy chain It is preferable, and, as for a weight average molecular weight, it is more preferable that it is 2000-50000. As polyethyleneimine, it is preferable to have a polyalkyleneoxy chain on a nitrogen atom, and what has a repeating unit represented by the following general formula is more preferable.

[Formula 1]

In the above formula, n represents a number of 2 to 200 (in the case of a mixture, the average number).

Moreover, it is preferable to use the thing whose HLB (Hydrophile-Lipophile Balance) value is 16-19 as for polyethyleneimine.

Although it does not restrict|limit especially as content of a hydrophilic polymer, 0.00001-2.0 mass % is preferable with respect to the total mass of polishing liquid, 0.0001-1.0 mass % is more preferable, 0.0001-1.0 mass % is still more preferable, 0.001-0.1 mass % is particularly preferred.

A hydrophilic polymer may be used individually by 1 type, and may use 2 or more types together. Moreover, you may use together surfactant and a hydrophilic polymer. When using together 2 or more types of hydrophilic polymers, it is preferable that total content exists in the said range.

<Organic solvent>

The polishing liquid may contain an organic solvent. It does not restrict|limit especially as an organic solvent, A well-known organic solvent can be used. Especially, a water-soluble organic solvent is preferable.

In addition, the said organic solvent is a component different from the alcohol A already demonstrated.

Examples of the organic solvent include ketone-based solvents, ether-based solvents, glycol ether-based solvents, and amide-based solvents.

More specifically, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, etc. are mentioned, for example.

Especially, methyl ethyl ketone, tetrahydrofuran, dioxane, N-methylpyrrolidone, etc. are more preferable.

Although it does not restrict|limit especially as content of an organic solvent, 0.001-5.0 mass % is preferable with respect to the total mass of a polishing liquid, and 0.01-2.0 mass % is more preferable.

Moreover, an organic solvent may be used individually by 1 type, and may use 2 or more types together. When using together 2 or more types of organic solvents, it is preferable that total content exists in the said range.

<water>

It is preferable that the said polishing liquid contains water. Although there is no restriction|limiting in particular as water contained in the said polishing liquid, Ion-exchange water, pure water, etc. can be used.

Although it does not restrict|limit especially as content of water, Usually, 90-99 mass % of the total mass of a polishing liquid is preferable.

<chelating agent>

The said polishing liquid may contain the chelating agent (namely, a water softener) as needed in order to reduce the adverse effect of polyvalent metal ion etc. mixed.

As the chelating agent, for example, a general-purpose water softener and/or its analog compound which are calcium and/or magnesium precipitation inhibitors can be used, and two or more of these may be used in combination as needed.

As content of a chelating agent, what is necessary is just sufficient quantity to block metal ions, such as a multivalent metal ion, to mix, For example, 0.001-2.0 mass % is preferable in the total mass of a polishing liquid.

[Method for producing abrasive solution]

It does not restrict|limit especially as a manufacturing method of the said polishing liquid, A well-known manufacturing method can be used. As a manufacturing method of a polishing liquid, the method of mixing an abrasive grain, an organic acid, and alcohol A is mentioned, for example. At this time, you may mix other components, for example, an azole compound, an oxidizing agent, a charge regulator, surfactant, organic solvent, water, and a chelating agent.

In addition, when mixing each said component, the order in particular of mixing each is not restrict|limited. For example, a mixture in which abrasive grains and alcohol A are pre-mixed may be prepared, and other components may be added to the mixture. The aspect which adds other components may be sufficient.

There is no restriction|limiting in particular about the method of making alcohol A into a predetermined amount with respect to the total mass of abrasive|polishing liquid. As said method, you may add so that it may become a predetermined amount with respect to the total mass of a polishing liquid, for example. In addition, when the raw material containing each component also contains alcohol A in advance, if the mixing ratio of the raw materials is adjusted so that the total amount of alcohol A contained in the raw material becomes a predetermined amount with respect to the total mass of the polishing liquid, the above A polishing liquid can be prepared.

Another aspect of the method for producing a polishing liquid includes a method of preparing a polishing liquid by adding an oxidizing agent (for example, hydrogen peroxide) to a polishing liquid stock solution in which components other than an oxidizing agent are mixed in advance, before production of the polishing liquid. . According to this manufacturing method, since the polishing liquid is obtained by mixing an oxidizing agent with the polishing liquid stock solution containing a predetermined component, it is easy to control the content of the oxidizing agent with respect to the total mass of the polishing liquid in a desired range. This is because some oxidizing agents decompose with time, and the content in the polishing liquid changes.

In another aspect of the method for producing a polishing liquid, a concentrated liquid of a polishing liquid containing a predetermined component is prepared, and at least one selected from the group consisting of an oxidizing agent and water is added thereto to obtain a polishing liquid having predetermined characteristics. A manufacturing method is mentioned.

[Chemical mechanical polishing method]

In the chemical mechanical polishing method according to an embodiment of the present invention, while supplying the polishing liquid to a polishing pad mounted on a polishing platen, a polishing target surface of an object to be polished is brought into contact with the polishing pad, and the polishing body and the polishing pad are It is a chemical mechanical polishing method (hereinafter also referred to as a "CMP method") comprising a step (hereinafter also referred to as a "polishing step") of relatively moving and polishing a surface to be polished to obtain a polished object.

[Subject to be polished]

Examples of the object to be polished by the CMP method include an embodiment containing at least one layer selected from the group consisting of copper, copper alloy, tungsten, tungsten alloy, silicon nitride, and polysilicon.

As the object to be polished, for example, a barrier metal film (barrier metal layer) formed on one surface on the surface of an interlayer insulating film (interlayer insulating layer) having recesses, and copper or a copper alloy formed so as to fill the recesses on the surface of the barrier metal film It is a board|substrate which has a conductor film (conductor layer). Such a substrate is typically a semiconductor substrate, and it is preferably an LSI having wirings made of copper metal and/or a copper alloy, and particularly preferably, the wirings are a copper alloy.

Examples of the object to be polished include materials at all stages that require planarization in the semiconductor device manufacturing process, such as a wafer in which a conductive material film is formed on a substrate, and a laminate in which a conductive material film is formed on an interlayer insulating film provided on a wiring formed on the substrate. can

Furthermore, among copper alloys, the copper alloy containing silver is preferable. The silver content contained in the copper alloy is preferably 40 mass % or less, more preferably 10 mass % or less, still more preferably 1 mass % or less, with respect to the layer of copper alloy in the range of 0.00001 to 0.1 mass %. have the best effect.

<substrate>

As an example of a board|substrate, what is used for the wafer manufacturing process for 8-inch or 12-inch semiconductors, or a micromachine manufacturing process is mentioned. As the kind, a silicon wafer for semiconductors, a silicon-on-insulator (SOI) wafer, or a sapphire substrate of a compound semiconductor used for a semiconductor laser or the like is also included. Other than that, it is also used to planarize the pattern formation surface after forming a wiring pattern on a polymer film substrate.

It is preferable that the diameter of the target wafer to which CMP is performed with a polishing liquid is 200 mm or more, and 300 mm or more is especially preferable.

<Interlayer Insulation Film>

As an interlayer insulating film, what has a dielectric constant of 2.6 or less is preferable, For example, silicon nitride, polysilicon, etc. are mentioned. In addition, the thickness of an interlayer insulating film can be suitably adjusted according to the upper part and lower part of the wiring in a multilayer wiring, or generation|generation (node).

<Barrier metal film>

The barrier metal film is a film (layer) disposed between a conductor film (wiring) made of copper or a copper alloy provided on a semiconductor substrate and an interlayer insulating film to prevent diffusion of copper.

The material of the barrier metal film is preferably a low-resistance metal material, and specifically preferably contains at least one selected from tantalum, a tantalum compound, titanium, a titanium compound, tungsten, a tungsten compound, and ruthenium. and TiN, TiW, Ta, TaN, W, WN, or Ru is more preferable. Moreover, as thickness of a barrier metal film, it is preferable to set it as about 20-30 nm.

The to-be-polished object used in the CMP method which concerns on the said embodiment can be manufactured by the following method, for example.

First, an interlayer insulating film such as silicon nitride or polysilicon is laminated on a silicon substrate. Then, by known means such as resist layer formation and etching, recesses (substrate exposed parts) of a predetermined pattern are formed on the surface of the interlayer insulating film to form an interlayer insulating film comprising convex parts and concave parts. On this interlayer insulating film, tungsten or a tungsten compound is deposited as a barrier layer covering the interlayer insulating film along the surface unevenness by vapor deposition, CVD (chemical vapor deposition), or the like. Further, copper and/or a copper alloy is formed by vapor deposition, plating, CVD or the like as a conductive material layer (hereinafter referred to as a conductor layer) for covering the barrier layer so as to fill the recessed portion to obtain an object to be polished having a laminate structure. As for the thickness of an interlayer insulating film, a barrier layer, and a copper layer, 0.01-2.0 micrometers, 1-100 nm, and about 0.01-2.5 micrometers are preferable, respectively.

[polishing device]

A 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.

The CMP apparatus includes, for example, a holder for holding an object to be polished (eg, a semiconductor substrate, etc.) having a surface to be polished, and a polishing platen to which a polishing pad is attached (a motor having a variable rotational speed is mounted). A general CMP apparatus equipped with can be used. As a commercial item, Reflexion (made by Applied Materials) can be used, for example.

<polishing pressure>

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

<The number of rotations of the polishing plate>

In the CMP method according to the above embodiment, it is preferable to perform the polishing at the rotation speed of the polishing platen of 50 to 200 rpm, and more preferably to perform the polishing at 60 to 150 rpm.

Further, in order to relatively move the polishing body and the polishing pad, the holder may be further rotated and/or oscillated, the polishing platen may be planetary rotation, or the belt-shaped polishing pad may be moved linearly in one direction in the long direction. . Note that the holder may be in any state of being fixed, rotating, or oscillating. 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 relatively moved.

<Supply method of polishing liquid>

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

Example

The present invention will be described in more detail below based on examples. Materials, amounts of use, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Accordingly, the scope of the present invention should not be construed as being limited by the Examples shown below. Incidentally, "%" means "mass %" unless otherwise specified.

[Example 1]

Each component shown below was mixed, and the chemical mechanical polishing liquid was prepared.

・Colloidal silica (average primary particle diameter: 35 nm, product name "PL3", manufactured by Fuso Chemical Industries, Ltd., corresponding to abrasive grains) 0.1% by mass

Glycine (organic acid, also corresponding to amino acid) 1.5% by mass

0.001 mass % of 5-methylbenzotriazole (corresponding to the azole compound containing a benzotriazole skeleton)

0.2 mass % of 3-amino-1,2,4-triazole (corresponding to a compound not containing a benzotriazole skeleton and also a compound containing a 1,2,4-triazole skeleton)

· Hydrogen peroxide (corresponding to oxidizing agent) 1.0% by mass

・Ammonium nitrate (corresponding to charge adjuster) 1000 mass ppm

·Methanol (corresponding to alcohol A) 500ppm

・Water (pure water) balance

[Examples 2-54, Comparative Examples 1-5]

Each component shown in Table 1, Table 2, Table 3, and Table 4 was mixed by the method similar to Example 1, and each polishing liquid was obtained. In addition, each abbreviation in Table 1 shows the following compounds, etc. In addition, "content" in Table 1 shows the value on a mass basis. The pH of each treatment liquid was adjusted to the target pH by adding _{KOH/H 2} SO _{4 .}

・PL3 (colloidal silica, product name "PL3", manufactured by Fuso Chemical Industries, Ltd., average primary particle diameter: 35 nm, equivalent to abrasive grains)

Gly (Glycine, organic acids also correspond to amino acids)

Ala (alanine, organic acid also corresponds to amino acid)

Asp (aspartic acid and organic acid also correspond to amino acids)

NMG (N-methylglycine, organic acid also corresponds to amino acid)

·MaloA (corresponding to malonic acid, organic acid)

·5-MBTA (5-methylbenzotriazole, corresponding to the azole compound containing a benzotriazole skeleton)

BTA (corresponding to benzotriazole, azole compound containing benzotriazole skeleton)

5,6-DMBTA (corresponding to 5,6-dimethylbenzotriazole, an azole compound containing a benzotriazole skeleton)

·5-ABTA (corresponds to 5-aminobenzotriazole, azole compound containing a benzotriazole skeleton)

3-AT (corresponding to 3-amino-1,2,4-triazole, azole compound not containing benzotriazole skeleton, and azole compound containing 1,2,4-triazole skeleton)

Triaz (corresponds to 1,2,4-triazole, azole compounds not containing a benzotriazole skeleton, and azole compounds containing a 1,2,4-triazole skeleton)

·3,5-DP (corresponding to azole compounds that do not contain 3,5-dimethylpyrazole or benzotriazole skeletons)

Pyraz (corresponds to azole compounds that do not contain a pyrazole or benzotriazole skeleton, and also a pyrazole compound containing a pyrazole skeleton)

・Imidaz (corresponds to imidazole, azole compounds not containing a benzotriazole skeleton, and also azole compounds containing imidazole skeletons)

5-ATZ (corresponds to 5-aminotetrazole, azole compounds that do not contain a benzotriazole skeleton)

Am-Ni (ammonium nitrate, corresponding to charge modifier)

Am-Bz (ammonium benzoate, corresponding to charge modifier)

Am-Ci (triammonium citrate, corresponding to charge modifier)

RE-610 (product name "Rhodafac RE-610", manufactured by Rhodia, corresponds to a surfactant)

・MD-20 (product name "Surfynol MD-20", manufactured by Air Products, corresponds to a surfactant)

・A43-NQ (product name "Takesurf-A43-NQ", manufactured by Takemoto Yushi, corresponds to anionic surfactant)

·S-465 (product name "Surfynol465", manufactured by Airproducts, corresponds to a nonionic surfactant)

DBSH (dodecylbenzenesulfonic acid, corresponding to surfactant)

MeOH (corresponds to methanol, alcohol A)

·HEDP (1-hydroxyethylidene-1,1-diphosphonic acid, corresponding to organic acid)

DTPA (diethylenetriamine pentaacetic acid, corresponding to organic acid)

PHEAA: N-(2-hydroxyethyl) acrylamide polymer (weight average molecular weight 20000, corresponding to hydrophilic polymer)

PEIEO: polyethyleneimine having an ethyleneoxy chain having a repeating unit represented by the following, HLB value 18, n number: 20 (corresponding to hydrophilic polymer)

[Formula 2]

[Evaluation of temporal stability of polishing liquid]

The change in the state of aggregation of each prepared polishing liquid was measured using Terviscan (manufactured by Seishin Industrial Co., Ltd.: Terbiscan MA2000). That is, the transmitted light intensity of the polishing liquid immediately after preparation and the transmitted light intensity of the polishing liquid after storage in a thermostat at 40° C. for 2 weeks were measured, and the results were evaluated according to the following criteria. The results are shown in Tables 1-4. Moreover, C or more is preferable practically.

A: The change in transmitted light intensity before and after storage is 1% or less.

B: The change in transmitted light intensity before and after storage is more than 1% and 3% or less.

C: The change in transmitted light intensity before and after storage is more than 3% and 5% or less.

D: The change in transmitted light intensity before and after storage is more than 5%.

[Evaluation of defect (scratch) performance]

Each polishing liquid was used to polish a blank Cu wafer, and the polished Cu wafer was washed with pure water, and then dried. The Cu wafer after drying was observed using the optical microscope, and the state to be polished of the Cu wafer was evaluated based on the following evaluation criteria. The results are shown in Tables 1-4. Moreover, C or more is preferable practically.

A: The total number of defects (number of defects/Cu wafer) is 3 or less

B: The total number of defects is 4 or more and 5 or less.

C: The total number of defects is 6 or more and 10 or less.

D: The total number of defects is 11 or more and 20 or less.

E: The total number of defects is 21 or more

[Measurement of Zeta Potential]

The surface potential (zeta potential) of the abrasive grains in each prepared polishing liquid was measured using a zeta electrometer (ELSZ-2000ZS, manufactured by Otsuka Electronics Co., Ltd.). The results are shown in Tables 1-4.

[Evaluation of grinding speed and dishing]

Polishing was performed while supplying the polishing liquid to the polishing pad under the following conditions, and the polishing rate and dishing were evaluated.

・Abrasive device: Reflexion (manufactured by Applied Materials)

・Object to be polished (wafer):

(1) for calculating the polishing rate;

Copper: A blanket wafer with a diameter of 300 mm in which a Cu film having a thickness of 1.5 μm is formed on a silicon substrate.

Tungsten: A 300 mm diameter blanket wafer with a 0.2 μm thick W film formed on a silicon substrate.

Silicon nitride: A 300 mm diameter blanket wafer in which a 1.5 μm thick silicon nitride film is formed on a silicon substrate.

Polysilicon: A blanket wafer with a diameter of 300 mm in which a 1.5 μm thick polysilicon film is formed on a silicon substrate.

(2) for dishing evaluation;

Copper: Copper wiring wafer (pattern wafer) with a diameter of 300 mm (mask pattern 754CMP (ATDF))

・Tungsten: Tungsten wiring wafer (pattern wafer) with a diameter of 300 mm (mask pattern 754CMP (ATDF))

Silicon nitride: silicon nitride wiring wafer (pattern wafer) with a diameter of 300 mm (mask pattern 754CMP (ATDF))

Polysilicon: Polysilicon wiring wafer (pattern wafer) with a diameter of 300 mm (Mask Pattern 754CMP (ATDF))

・Abrasive pad: IC1010 (manufactured by Rhodel)

· grinding conditions;

Polishing pressure (contact pressure between surface to be polished and polishing pad): 1.5 psi

Abrasive fluid supply rate: 200ml/min

Grinding plate rotation speed: 110rpm

Grinding head rotation speed: 100rpm

(Assessment Methods)

Calculation of polishing rate: The blanket wafer of (1) is polished for 60 seconds, and the metal film thickness before and after polishing is obtained by converting the electrical resistance value at 49 equally spaced locations on the wafer surface, and dividing them by the polishing time The average value of the calculated|required values was made into the grinding|polishing speed, and it evaluated according to the following criteria. The results are shown in Tables 1-4. Moreover, as a polishing rate, C or more is preferable practically.

·Cu (Cu) polishing rate:

A: The polishing rate is 400 nm/min or more.

B: The polishing rate is 300 nm/min or more and less than 400 nm/min.

C: The polishing rate is 200 nm/min or more and less than 300 nm/min.

D: The polishing rate is less than 200 nm/min.

·Tungsten (W) polishing rate:

A: The polishing rate is 250 nm/min or more.

B: The polishing rate is 150 nm/min or more and less than 250 nm/min.

C: The polishing rate is 50 nm/min or more and less than 150 nm/min.

D: The polishing rate is less than 50 nm/min.

Silicon nitride (SiN) polishing rate:

A: The polishing rate is 30 nm/min or more.

B: The polishing rate is 20 nm/min or more and less than 30 nm/min.

C: The polishing rate is 10 nm/min or more and less than 20 nm/min.

D: The polishing rate is less than 10 nm/min.

·Poly-Si polishing rate:

A: The polishing rate is 100 nm/min or more.

B: The polishing rate is 70 nm/min or more and less than 100 nm/min.

C: The polishing rate is 40 nm/min or more and less than 70 nm/min.

D: The polishing rate is less than 40 nm/min.

Evaluation of dishing: With respect to the pattern wafer of (2), in addition to the time until the copper of the non-wiring portion is completely polished, polishing is additionally performed by 25% of the time, and the line and space portion (line 10 µm) , space 10 µm) was measured with a contact-type step meter DektakV320Si (manufactured by Veeco), and evaluated according to the following criteria. The results are shown in Tables 1-4. Moreover, evaluation G or more is preferable practically.

A: The dishing is 15 nm or less.

B: The dishing is more than 15 nm and 20 nm or less.

C: The dishing is more than 20 nm and 25 nm or less.

D: The dishing is more than 25 nm and 30 nm or less.

E: The dishing is more than 30 nm and 35 nm or less.

F: The dishing is more than 35 nm and 40 nm or less.

G: The dishing is more than 40 nm and 45 nm or less.

H: dishing is more than 45 nm.

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(Table 1) In Table 1, the compositions, etc. of the polishing liquids according to Examples and Comparative Examples were described for each row in Table 1 (Part 1) [1] to [3]. For example, the polishing liquid of Example 1 contains 0.1 mass % of PL3 as an abrasive grain (relative to the total mass of the abrasive liquid, the same applies hereinafter), contains 1.5 mass % of Gly as an organic acid, and 5-MBTA as an anticorrosive agent. and 3-AT, each containing 0.001 mass % and 0.2 mass %, containing _{1.0 mass % of H 2} O ₂ as an oxidizing agent, containing 1000 mass ppm of Am-Ni as a charge method agent, and containing 500 mass ppm of MeOH as alcohol A ppm, and the balance is water. pH is 7, the content ratio of the content of alcohol A to each component is 0.50 with respect to the abrasive grain, 0.033 with respect to the organic acid, 0.25 with respect to the anticorrosive agent (total), 0.050 with respect to the oxidizing agent, and 0.50 with respect to the charge aid; The zeta potential was -45 mV, the stability over time was "A", the Cu polishing rate was 375 nm/min, the evaluation was "B", the dishing was 17 nm, the evaluation was "B", and the defect performance was "A".

The above is the same about (Table 1) 2 and Tables 2-4.

[Example 55]

In Example 1, the polishing liquid according to Example 55 was prepared in the same manner except that ethanol was used instead of methanol, and the same evaluation as above was performed, and the evaluation result was the same as in Example 1.

[Example 56]

A polishing liquid according to Example 56 was prepared in the same manner as in Example 1 except that 1-propanol was used instead of methanol, and the same evaluation as above was performed, and the evaluation result was the same as in Example 1.

[Example 57]

In Example 1, except that isopropanol was used instead of methanol, a polishing liquid according to Example 57 was prepared in the same manner, and the same evaluation as above was performed, and the evaluation result was the same as in Example 1.

[Example 58]

The polishing liquid according to Example 58 was prepared in the same manner as in Example 1, except that the abrasive grains were changed from PL3 to PL2 (colloidal silica, product name "PL2", manufactured by Fuso Chemical Industries, Ltd., average primary particle diameter: 25 nm). When it produced and evaluated similar to the above, it was the same evaluation result as Example 1.

From the results shown in Table 1, as a polishing liquid for chemical mechanical polishing containing abrasive grains, organic acid, and alcohol A, alcohol A is at least one selected from the group consisting of methanol, ethanol, 1-propanol, and isopropanol, The polishing liquid of Examples 1-41 in which content of alcohol A is 1.0-800 mass ppm with respect to the total mass of polishing liquid had the desired effect.

On the other hand, the polishing liquids of Comparative Examples 1-4 did not have the desired effect.

In addition, the polishing liquids of Examples 1, 3, and 4, in which the content ratio of alcohol A to organic acid is 0.001 to 0.05, has better stability with time compared to the polishing liquid of Example 2, and, furthermore, CMP When applied to , the occurrence of defects was more suppressed. Moreover, it had the more excellent polishing rate and dishing performance.

The polishing liquid had a more excellent polishing rate and dishing performance as compared with the polishing liquid of Example 5.

Moreover, when the polishing liquid of Examples 1, 39, and 40 in which the content of the charge modifier was 10-1000 mass ppm was applied to CMP, compared with the polishing liquid of Example 38, the occurrence of defects was more suppressed. . On the other hand, compared with the polishing liquid of Example 37, the polishing liquid had more excellent stability with time, and when applied to CMP, the occurrence of defects was further suppressed.

Further, the polishing liquids of Examples 3, 4, 1, 5, 40, and 39, in which the content ratio of alcohol A to the charge control agent by mass ratio of 0.1 to 50, were superior to the polishing liquid of Example 41 over time stability and, when applied to CMP, the occurrence of defects was more suppressed. Moreover, it had the more excellent polishing rate. On the other hand, compared with the polishing liquid of Example 38, the above-mentioned polishing liquid had more excellent stability with time, and when applied to CMP, the occurrence of defects was more suppressed.

In addition, the polishing liquids of Examples 11, 1, and 12 having a pH of 5.0 to 8.0 have better stability with time compared to the polishing liquid of Example 10, and when applied to CMP, the occurrence of defects is more was restrained On the other hand, the polishing liquid had more excellent dishing performance as compared with the polishing liquid of Example 13.

Moreover, the polishing liquid of Examples 1 and 15, whose content of organic acid is 1.0-20 mass %, had the more excellent polishing rate compared with the polishing liquid of Example 14. On the other hand, the polishing liquid had more excellent dishing performance as compared with the polishing liquid of Example 16.

Claims (27)

A polishing liquid for chemical mechanical polishing comprising abrasive grains, an organic acid, alcohol A, and a charge control agent, the polishing liquid comprising:
Content of the said organic acid is 1.0-20 mass % with respect to the total mass of the said polishing liquid,
The alcohol A is at least one selected from the group consisting of methanol, ethanol, 1-propanol, and isopropanol,
The content of the alcohol A is 1.0 to 800 mass ppm in the total mass of the polishing liquid,
The charge control agent contains at least one selected from the group consisting of ammonium salts of organic acids and ammonium salts of inorganic acids,
The polishing liquid has a pH of 5.0 to 8.0. The method according to claim 1,
The polishing liquid, wherein the content ratio of the alcohol A to the organic acid is 0.001 to 0.05. The method according to claim 1,
The said charge control agent is at least 1 sort(s) selected from the group which consists of an ammonium salt of an organic acid, ammonium sulfate, ammonium hydrochloride, and ammonium nitrate, polishing liquid. The method according to claim 1,
Polishing liquid, wherein content of the said charge control agent is 10-1000 mass ppm with respect to the total mass of the said polishing liquid. The method according to claim 1,
The polishing liquid of which content ratio of the said alcohol A with respect to the said charge control agent is 0.1-50. The method according to claim 1,
The polishing liquid, wherein the organic acid is an amino acid. 7. The method of claim 6,
The amino acids are glycine, alanine, arginine, isoleucine, leucine, valine, phenylalanine, asparagine, glutamine, lysine, histidine, proline, tryptophan, aspartic acid, glutamic acid, serine, threonine, tyrosine, cysteine, methionine, and The polishing liquid which is at least 1 sort(s) selected from the group which consists of N-methylglycine. 7. The method of claim 6,
A polishing liquid containing two or more of the above amino acids. delete The method according to claim 1,
The polishing liquid which further contains an oxidizing agent. 11. The method of claim 10,
Polishing liquid containing 2 or more types of said oxidizing agent. The method according to claim 1,
The polishing liquid which further contains 2 or more types of azole compounds. 13. The method of claim 12,
A polishing liquid comprising a benzotriazole compound and an azole compound different from the benzotriazole compound as the two or more azole compounds. 14. The method of claim 13,
The polishing liquid, wherein the azole compound different from the benzotriazole compound is at least one selected from the group consisting of a 1,2,4-triazole compound, a pyrazole compound, and an imidazole compound. delete The method according to claim 1,
The abrasive grain is colloidal silica, polishing liquid. While supplying the polishing liquid according to any one of claims 1 to 8, 10 to 14, and 16 to a polishing pad mounted on a polishing platen, a polishing target surface of an object to be polished is brought into contact with the polishing pad, A chemical mechanical polishing method comprising: an object to be polished; and a step of polishing the surface to be polished by relatively moving the polishing pad to obtain a polished object having been polished. 18. The method of claim 17,
The chemical mechanical polishing method, wherein the object to be polished contains at least one layer selected from the group consisting of copper, copper alloy, tungsten, tungsten alloy, silicon nitride, and polysilicon. delete delete delete delete delete delete delete delete delete