JP6652638B2 - Polishing liquid and chemical mechanical polishing method - Google Patents

Description

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

In the manufacture of large-scale integrated circuits (LSIs), chemical mechanical polishing (CMP) is used for flattening bare wafers, flattening interlayer insulating films, forming metal plugs, and forming embedded wiring. ) Method is used.
As a polishing liquid used for CMP, for example, Patent Literature 1 discloses "polishing characterized by containing alcohol, abrasive grains and water having a solubility in water of 0.5 to 8% by weight at a liquid temperature of 25 ° C. Liquid. "

JP 2004-74175 A

  The present inventor has examined the polishing liquid described in Patent Literature 1 and found that when the polishing liquid is stored, there is a problem that the abrasive grains contained in the polishing liquid easily aggregate. In addition, it has been clarified that when the above polishing liquid is applied to CMP, there is a problem that a defect is easily generated on a surface to be polished of a polished body.

Thus, the present invention provides a method for polishing abrasive grains that is difficult to agglomerate (in other words, “has excellent stability over time”), and that the surface to be polished has defects (in other words, “scratch”) even when applied to CMP. It is an object to provide a polishing liquid which is hardly generated.
Another object of the present invention is to provide a chemical mechanical polishing method.

The present inventor has conducted intensive studies to achieve the above object, and as a result, a polishing liquid for chemical mechanical polishing containing abrasive grains, an organic acid, and a predetermined alcohol A, which contains alcohol A The present inventors have found that a polishing liquid having an amount within a predetermined range can solve the above-mentioned problem, and have completed the present invention.
That is, it has been found that the above-described object can be achieved by the following configuration.

[1] A polishing solution for chemical mechanical polishing containing abrasive grains, an organic acid, and alcohol A, wherein the alcohol A is selected from the group consisting of methanol, ethanol, 1-propanol, and isopropanol. The polishing liquid, wherein the content of alcohol A is 1.0 to 800 ppm by mass based on the total mass of the polishing liquid.
[2] The polishing liquid according to [1], wherein the content ratio of the alcohol A to the organic acid is from 0.001 to 0.05.
[3] Further, a charge control agent is contained, and 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, [1] or The polishing liquid according to [2].
[4] The polishing liquid according to [3], wherein the content of the charge control agent is 10 to 1000 ppm by mass relative 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] The amino acid is glycine, alanine, arginine, isoleucine, leucine, valine, phenylalanine, asparagine, glutamine, lysine, histidine, proline, tryptophan, aspartic acid, glutamic acid, serine, threonine, tyrosine, cysteine, methionine, and N- The polishing liquid according to [6], which is at least one selected from the group consisting of 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], comprising 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% by mass based on 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 the polishing liquid according to any one of [1] to [16] is supplied to the polishing pad attached to the polishing table, the surface to be polished of the object to be polished is brought into contact with the polishing pad. And a step of relatively moving a polishing pad to grind a surface to be polished to obtain a polished body to be polished.
[18] The chemical mechanical polishing 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. Method.

According to the present invention, there is provided a polishing liquid which has excellent stability over time and hardly causes defects on a polished surface even when applied to CMP (hereinafter also referred to as “having the effects of the present invention”). can do.
Further, according to the present invention, a chemical mechanical polishing method can be provided.

Hereinafter, the present invention will be described in detail based on embodiments.
The description of the components described below is based on the embodiments of the present invention, and the present invention is not limited to such embodiments.
In addition, in this specification, the numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit.

[Polishing liquid]
The polishing liquid according to one embodiment of the present invention is a polishing liquid for chemical mechanical polishing containing abrasive grains, an organic acid, and alcohol A, wherein the alcohol A comprises methanol, ethanol, -The polishing liquid is at least one selected from the group consisting of propanol and isopropanol, and has a content of alcohol A of 1.0 to 800 ppm by mass in the total mass of the polishing liquid. In this specification, ppm means parts per million.

[Alcohol A (Alc)]
One of the features of the above polishing liquid is that the content of alcohol A is 1.0 to 800 ppm by mass based on the total mass of the polishing liquid.
When the content of the alcohol A exceeds the upper limit, the absolute value of the zeta potential of the abrasive grains surface (particularly, the surface of colloidal silica) decreases, and the abrasive grains are easily aggregated in the polishing liquid during storage, and the stability over time. Is estimated to decrease.
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 be generated on the surface of the object to be polished.

  The content of the alcohol A is 1.0 to 800 ppm by mass, preferably 1.0 to 750 ppm by mass, and more preferably 10 to 500 ppm by mass, based on the total mass of the polishing liquid.

The alcohol A is at least one selected from the group consisting of methanol, ethanol, 1-propanol, and isopropanol.
As the alcohol A, one type may be used alone, or two or more types may be used in combination. When two or more alcohols A are used in combination, the total content of the two or more alcohols A is 1.0 to 800 ppm by mass, and the preferable range is as described above.

In this specification, the content of alcohol A in the polishing liquid is intended to be the content measured by the following method.
The measurement of the alcohol A content in the polishing liquid is performed using gas chromatography. The measurement conditions of gas chromatography are as follows. When the mixing ratio of each component of the polishing liquid is clear, the alcohol A content is determined from the alcohol A mixing ratio with respect to the total mass of the polishing liquid, and the above measurement can be replaced.

・ Gas chromatography: 7890 series manufactured by Agilent Technologies ・ Temperature rising condition: Initial temperature 40 ° C., temperature rising rate to 250 ° C. at a rate of 10 ° C./min. ・ Capillary column: Agilent J & B GC column DB-WAX, 60 m × 0. 25 mm (inner diameter), film thickness: 0.25 μm
・ Carrier gas flow rate: helium 1.0mL / min ・ Injection port temperature: 250 ° C
・ Hydrogen flame ion detector temperature: 300 ℃

(PH)
The pH of the polishing liquid is not particularly limited, but is usually preferably from 1.0 to 14.0. Above all, 5.0 to 8.0 is more preferable.
When the pH is 5.0 or more, a polishing liquid having better stability over time can be obtained, and even when the polishing liquid is applied to CMP, defects are less likely 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 on the surface of colloidal silica is around pH 4.0, the pH of the polishing liquid must be within the above range, which is higher than the above isoelectric point. The present inventors presume that the adjustment to make the abrasive grains harder to aggregate.
On the other hand, when the pH is 8.0 or less, dishing is less likely to occur on the surface of the object to be polished when the polishing liquid is applied to CMP.

[Abrasive (A)]
The polishing liquid contains abrasive grains. The abrasive grains are not particularly limited, and known abrasive grains can be used.
Examples of abrasive grains include inorganic abrasive grains such as silica, alumina, zirconia, ceria, titania, germania, and silicon carbide; and organic abrasive grains such as polystyrene, polyacryl, and polyvinyl chloride. Among them, silica particles are preferred as abrasive grains in terms of excellent dispersion stability in a polishing liquid and a small number of polishing scratches (scratch) generated by CMP.
The silica particles are not particularly limited, and include, for example, precipitated silica, fumed silica, and colloidal silica. Among them, colloidal silica is more preferred.

The average primary particle diameter of the abrasive grains is not particularly limited, but is preferably from 1 to 100 nm in that the polishing liquid has more excellent dispersion stability. The average primary particle diameter can be confirmed by a manufacturer's catalog or the like.
Examples of commercially available abrasives include, as colloidal silica, PL-1, PL-2, PL-3, PL-7, and PL-10H (all trade names, manufactured by Fuso Chemical Industry Co., Ltd.). Can be

The content of the abrasive grains is not particularly limited, and is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, preferably 10% by mass or less, and more preferably 5% by mass or less based on the total mass of the polishing liquid. Is more preferred. Within the above range, a more excellent polishing rate can be obtained when the polishing liquid is applied to CMP.
One type of abrasive may be used alone, or two or more types may be used in combination. When two or more abrasive grains are used in combination, the total content is preferably within the above range.

The content of the abrasive grains 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 0.0001 to 1.5. Preferably, it is 0.01 to 0.08, more preferably 0.1 to 0.7.
When the Alc / A ratio is 0.1 to 0.7, a more excellent polishing rate can be obtained when the polishing liquid is applied to CMP.

[Organic acid (B)]
The polishing liquid contains an organic acid. The organic acid is a compound different from an oxidizing agent and a charge adjusting agent described later, and has an effect of accelerating metal oxidation, adjusting the pH of the polishing liquid, and acting as a buffer.
As the organic acid, a water-soluble organic acid is preferable.
The organic acid is not particularly limited, and a known organic acid can be used.
Examples of the organic acid include 1-hydroxyethylidene-1,1-diphosphonic acid (hereinafter also referred to as “HEDP”), diethylenetriaminepentaacetic 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-methylhexanoic acid, n-octanoic acid, -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, Hydroxyethyl iminodiacetic acid, iminodiacetic acid and the like.

As the organic acid, an amino acid is more preferable in that it has better water solubility.
The amino acid is not particularly limited, and a known amino acid can be used.
Examples of amino acids include glycine, alanine (α-alanine and / or β-alanine), arginine, isoleucine, leucine, valine, phenylalanine, asparagine, glutamine, lysine, histidine, proline, tryptophan, aspartic acid, glutamic acid, glutamic acid, serine, Threonine, tyrosine, cysteine, methionine, N-methylglycine and the like.
Among them, glycine, α-alanine, β-alanine, L-aspartic acid, or methyl glycine (N-methyl glycine) is preferable as the amino acid in that the polishing liquid has a more excellent effect of the present invention. And / or methylglycine is more preferred.
One amino acid may be used alone, or two or more amino acids may be used in combination. When two or more amino acids are used in combination, the total content is preferably within the above range.
Above all, the polishing liquid preferably contains two or more amino acids from the viewpoint that a polishing liquid having more excellent effects of the present invention can be obtained.
The two or more amino acids are not particularly limited, and the above amino acids can be used in combination. Among them, glycine and alanine are two or more amino acids in that, when a polishing liquid is applied to CMP, a higher polishing rate can be obtained and dishing is less likely to occur on the surface of the object to be polished. , Alanine and N-methylglycine, and glycine and N-methylglycine are preferred.

The content of the organic acid is not particularly limited, and is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, based on the total mass of the polishing liquid. It is preferably at most 50% by mass, more preferably at most 25% by mass, further preferably at most 20% by mass, particularly preferably at most 10% by mass.
When the content of the organic acid is 0.1% by mass or more, a more excellent polishing rate can be obtained when the polishing liquid is applied to CMP. If the content of the organic acid is 50% by mass or less, dishing is less likely to occur on the surface to be polished when the polishing liquid is applied to CMP.
When the content of the organic acid is 1.0 to 20% by 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 two or more organic acids are used in combination, the total content is preferably within the above range.

It is preferable that the content of the organic acid and the content of the alcohol A satisfy the following relationship. That is, the mass ratio of the content of the alcohol A to the content of the organic acid (alcohol A content / organic acid content; also referred to as “Alc / B” ratio) is 0.0001 to 0.2. Preferably, it is 0.0006 to 0.1, more preferably 0.001 to 0.05.
When the Alc / B ratio is 0.001 to 0.05, a higher polishing rate can be obtained when the polishing liquid is applied to CMP.

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

<Corrosion inhibitor (C)>
The polishing liquid may contain an anticorrosive.
It is preferable that the anticorrosive agent has a function of adhering to the surface to be polished of the object to be polished to form a film and controlling corrosion of the metal. The anticorrosive is not particularly limited, and known anticorrosives can be used. Among them, azole compounds are preferable.

(Azole compound)
In the present specification, an azole compound is intended to mean a compound containing a five-membered heterocyclic ring containing one or more nitrogen atoms, and the number of nitrogen atoms is preferably 1 to 4. Further, the azole compound may contain an atom other than a nitrogen atom as a hetero atom.
In addition, the above-described derivative intends a compound having a substituent that the 5-membered heterocyclic ring may contain.

Examples of the azole compound include a pyrrole skeleton, an imidazole skeleton, a pyrazole skeleton, an isothiazole skeleton, an isoxazole skeleton, a triazole skeleton, a tetrazole skeleton, an imidazole skeleton, a thiazole skeleton, an oxazole skeleton, an isoxazole skeleton, a thiadiazole skeleton, and oxadiazole. And a compound having a skeleton and a tetrazole skeleton.
The azole compound may be an azole compound having a polycyclic structure further containing a condensed ring in the above skeleton. Examples of the azole compound containing a polycyclic structure include, for example, a compound containing an indole skeleton, a purine skeleton, an indazole skeleton, a benzimidazole skeleton, a carbazole skeleton, a benzoxazole skeleton, a benzothiazole skeleton, a benzothiadiazole skeleton, and a naphthoimidazole skeleton. Is mentioned.

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) and an alkyl group (a linear, branched, or cyclic alkyl group; Even if it is a polycyclic alkyl group such as an alkyl group, it may contain an active methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regardless of the substitution position), an acyl group, an alkoxycarbonyl group An aryloxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group (carbamoyl groups having a substituent include, for example, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, Thiocarbamoyl group and N-sulfamoylcarbamoyl group ), A carbazoyl group, a carboxyl group or a salt thereof, an oxalyl group, an oxamoyl group, a cyano group, a carboximidoyl group, a formyl group, a hydroxy group, an alkoxy group (including an ethyleneoxy group or a propyleneoxy group as a repeating unit). Group), an aryloxy group, a heterocyclic oxy group, an acyloxy group, a carbonyloxy group, a carbamoyloxy group, a sulfonyloxy group, an amino group, an acylamino group, a sulfonamide group, a ureido group, a thioureido group, and an N-hydroxyureido group Imide group, carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonyluureido group, N-acylureido group, An acylsulfamoylamino group, a hydroxyamino group, a nitro group, a heterocyclic group containing a quaternized nitrogen atom (for example, a pyridinio group, an imidazolio group, a quinolinio group, and an isoquinolinio group), an isocyano group, Imino group, mercapto group, (alkyl, aryl, or heterocycle) thio group, (alkyl, aryl, or heterocycle) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or Salt, sulfamoyl group (as the sulfamoyl group having a substituent, for example, N-acylsulfamoyl group and N-sulfonylsulfamoyl group) or a salt thereof, phosphino group, phosphinyl group, phosphinyloxy group , A phosphinylamino group, and a silyl group. .
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, and a polycyclic alkyl group such as a bicycloalkyl group) An active methine group may be included), an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group (substitution position does not matter).

  Here, the “active methine group” means a methine group substituted with two electron withdrawing groups. The `` electron-withdrawing group '' includes, 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. The two electron-withdrawing groups may be bonded to each other to form a cyclic structure. In addition, “salt” intends a cation such as an alkali metal, an alkaline earth metal, and a heavy metal; and an organic cation such as an ammonium ion and a phosphonium ion.

  As the azole compound, specifically, 5-methylbenzotriazole, 5-aminobenzotriazole, benzotriazole, 5,6-dimethylbenzotriazole, 3-amino-1,2,4-triazole, 1,2,2 4-triazole, 3,5-dimethylpyrazole, pyrazole, imidazole and the like.

The content of the azole compound is preferably 0.001 to 1.6% by mass based on the total mass of the polishing liquid.
In addition, an azole compound may be used individually by 1 type, or may use 2 or more types together. When two or more azole compounds are used in combination, the total content is preferably within the above range.
Among them, it is preferable to use two or more azole compounds in combination, in that a polishing liquid having more excellent effects of the present invention can be obtained. In addition, each aspect of the two or more azole compounds is the same as the aspect of the azole compound described above.

  As the two or more azole compounds, a benzotriazole compound (a compound having a benzotriazole skeleton) and a compound different from the benzotriazole compound (a benzotriazole (A compound not containing a skeleton).

  The compound not containing the benzotriazole skeleton is not particularly limited, but is composed of a 1,2,4-triazole compound, a pyrazole compound, and an imidazole compound in that a polishing liquid having a better effect of the present invention can be obtained. It is preferably at least one selected from the group.

The content of the anticorrosive (C) is preferably 0.001 to 1.6% by mass based on the total mass of the polishing liquid.
The anticorrosive (C) may be used alone or in combination of two or more. When two or more anticorrosives (C) are used in combination, the total content is preferably within the above range.

The content of the anticorrosive (C) preferably satisfies the following relationship with the content of the alcohol A. That is, the mass ratio of the content of alcohol A to the content of anticorrosive (alcohol A content / content of anticorrosive; also referred to as “Alc / C” ratio) is preferably 0.004 or more, and 0 or more. .0045 or more is more preferable, 0.01 or more is more preferable, 0.03 or more is particularly preferable, 0.04 or more is most preferable, 30 or less is preferable, 25 or less is more preferable, and 5 or less is more preferable.
When the Alc / C ratio is 0.01 or more, a more excellent polishing rate can be obtained when the polishing liquid is applied to CMP. If the Alc / C ratio is 0.04 or more, dishing is less likely to occur on the 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 surface of the object to be polished when the polishing liquid is provided to the CMP.

<Oxidizing agent (D)>
The polishing liquid may contain an oxidizing agent. The oxidizing agent is not particularly limited, and a known oxidizing agent can be used.
Examples of the oxidizing agent include hydrogen peroxide, peroxide, nitric acid, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, and persulfate. Examples include salts, dichromates, permanganates, ozone water, silver (II) salts, iron (III) salts, and the like, with hydrogen peroxide being more preferred. One oxidizing agent may be used alone, or two or more oxidizing agents may be used in combination.
Above all, when applied to CMP of a substrate (substrate 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 can be obtained. From the viewpoint, it is preferable to use two or more oxidizing agents.

When two or more oxidizing agents are used in combination, it is preferable to use a first oxidizing agent having a higher oxidation-reduction potential and a second oxidizing agent (G) having a lower oxidation-reduction potential.
As the first oxidizing agent, for example, among the above-mentioned oxidizing agents, at least one selected from the group consisting of hydrogen peroxide and peroxide is preferable, and hydrogen peroxide is more preferable.
As the second oxidizing agent, for example, among the above oxidizing agents, iron (III) salts are preferable, and at least one selected from the group consisting of iron nitrate, iron phosphate, iron sulfate, and potassium ferricyanide is more preferable. And iron nitrate (Fe (NO ₃ ) ₃ ) is more preferred.

The content of the oxidizing agent is not particularly limited, but is preferably 0.1 to 9.0% by mass based on the total mass of the polishing liquid.
When the content of the oxidizing agent is 0.1% by mass or more, a more excellent polishing rate can be 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.
When two or more oxidizing agents are used in combination, the total content is preferably within the above range.

The content of the oxidizing agent preferably satisfies the following relationship with the content of the alcohol A. That is, the mass ratio of the content of alcohol A to the content of oxidant (content of alcohol A / content of oxidant; also referred to as “Alc / D” ratio) is 0.000.5 or more. Preferably, it is more preferably 0.005 or more, further preferably 0.04 or more, preferably 0.09 or less, more preferably 0.07 or less.
When the Alc / D ratio is 0.005 or more, a more excellent polishing rate can be obtained when the polishing liquid is applied to CMP. If the Alc / D ratio is 0.04 or more, dishing is less likely to occur on the surface of the object to be polished when the polishing liquid is applied to CMP. When the Alc / D ratio is 0.07 or less, a more excellent polishing rate can be obtained when the polishing liquid is applied to CMP.

  When the first oxidizing agent and the second oxidizing agent are used in combination, the content of the second oxidizing agent preferably satisfies the following relationship with the content of the alcohol A. That is, the mass ratio of the content of alcohol A to the content of second oxidant (content of alcohol A / content of second oxidant; also referred to as “Alc / G” ratio) is 0. .1 to 20 are preferred.

<Charge control agent (E)>
The polishing liquid may contain a charge control agent. The charge control agent is not particularly limited, and a known charge control agent can be used. The charge control 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.
Examples of the charge control agent include an acid, an alkali, and a salt compound. Among them, the charge control agent is at least one selected from the group consisting of an inorganic acid, an ammonium salt of an organic acid, and an ammonium salt of an inorganic acid, in that a polishing liquid having a better effect of the present invention can be obtained. It is preferred to contain.
Examples of the inorganic acid include sulfuric acid, hydrochloric acid, and nitric acid.
Examples of the ammonium salt of an organic acid include ammonium benzoate and ammonium citrate.
Examples of the ammonium salt of an inorganic acid include ammonium sulfate, ammonium hydrochloride, and ammonium nitrate.

The content of the charge control agent is not particularly limited, but is preferably 0.5 mass ppm or more, more preferably 1 mass ppm or more, still more preferably 10 mass ppm or more, and more preferably 2 mass% based on the total mass of the polishing liquid. Or less, more preferably 1200 mass ppm or less.
When the content of the charge control agent is 10 ppm by mass or more, even when the polishing liquid is applied to CMP, defects are less likely to occur on the surface to be polished.
Further, when the content of the charge control agent is 1000 ppm or less, the polishing liquid has more excellent stability over time, and when the polishing liquid is applied to CMP, a higher polishing rate is obtained, and the polishing object is obtained. Dishing hardly occurs on the surface to be polished.
In addition, a charge control agent may be used individually by 1 type, or may use 2 or more types together. When two or more charge control agents are used in combination, the total content is preferably within the above range.

It is preferable that the content of the charge control agent satisfies the following relationship with the content of the alcohol A. That is, the mass ratio of the content of the alcohol A to the content of the charge control agent (the ratio of the content of the alcohol A / the content of the charge control agent; also referred to as the “Alc / E” ratio) is 0.005. Or more, more preferably 0.1 or more, preferably 500 or less, more preferably 50 or less, and even more preferably less than 5.
When the Alc / E ratio is 0.1 or more, a polishing liquid having more excellent temporal stability can be obtained, and when the polishing liquid is applied to CMP, a higher polishing rate can be obtained, and the polishing object can be obtained. Dishing is less likely to occur on the polished surface.
When the Alc / E ratio is 50 or less, even when the polishing liquid is applied to CMP, defects are less likely to occur on the surface to be polished.
If the Alc / E ratio is less than 5, more excellent effects of the present invention can be obtained.

<Surfactant (F)>
The polishing liquid may contain a surfactant. The surfactant has an effect of reducing the contact angle of the polishing liquid with the surface to be polished, and the polishing liquid easily spreads 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 carboxylate, sulfonate such as alkylbenzenesulfonic acid, sulfate, and phosphate.
Examples of the cationic surfactant include an aliphatic amine salt, an aliphatic quaternary ammonium salt, a benzalkonium chloride salt, a benzethonium chloride, a pyridinium salt, and an imidazolinium salt.
Examples of the amphoteric surfactant 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, fluorine type surfactant, and silicon type surfactant.

The content of the surfactant is not particularly limited, but is preferably 0.00001 to 2.0% by mass, more preferably 0.0001 to 1.0% by mass, and 0.001 to 1.0% by mass based on the total mass of the polishing liquid. 0.1 mass% is more preferred.
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.
One surfactant may be used alone, or two or more surfactants may be used in combination. When two or more surfactants are used in combination, the total content is preferably within the above range.

It is preferable that the content of the surfactant satisfies the following relationship with the content of the alcohol A. That is, the mass ratio of the content of alcohol A to the content of surfactant (content of alcohol A / content of surfactant; also referred to as “Alc / F” ratio) is 0.001 to 100. Is preferable, 0.002 to 80 is more preferable, and 0.005 to 50 is still more preferable.
When the Alc / F ratio is within the above range, a polishing liquid having more excellent defect performance can be 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 polyglycols such as polyethylene glycol, alkyl ethers of polyglycols, polysaccharides such as polyvinyl alcohol A, polyvinylpyrrolidone, and alginic acid, and carboxylic acid-containing polymers such as polymethacrylic acid and polyacrylic acid. , Polyacrylamide, polymethacrylamide, polyethyleneimine and the like. Specific examples of such a hydrophilic polymer include water-soluble polymers described in JP-A-2009-88243, paragraphs 0042 to 0044, and JP-A-2007-194261, paragraph 0026.

  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 a nitrogen atom (for example, N- (2-hydroxyethyl) acrylamide polymer or the like) or those having a substituent having a polyalkyleneoxy chain are preferable, and the weight average More preferably, the molecular weight is from 2000 to 50,000. As the polyethyleneimine, those having a polyalkyleneoxy chain on a nitrogen atom are preferable, and those having a repeating unit represented by the following general formula are more preferable.

In the above formula, n represents a number of 2 to 200 (in the case of a mixture, an average number thereof).
Further, it is preferable to use polyethyleneimine having an HLB (Hydrophile-Lipophile Balance) value of 16 to 19.

The content of the hydrophilic polymer is not particularly limited, but is preferably 0.00001 to 2.0% by mass, more preferably 0.0001 to 1.0% by mass, and 0.0001 to 1.0% by mass based on the total mass of the polishing liquid. 1.0 mass% is more preferable, and 0.001 to 0.1 mass% is particularly preferable.
One type of hydrophilic polymer may be used alone, or two or more types may be used in combination. Further, a surfactant and a hydrophilic polymer may be used in combination. When two or more hydrophilic polymers are used in combination, the total content is preferably within the above range.

<Organic solvent>
The polishing liquid may contain an organic solvent. The organic solvent is not particularly limited, and a known organic solvent can be used. Among them, a water-soluble organic solvent is preferred.
The organic solvent is a component different from the alcohol A described above.
Examples of the organic solvent include ketone, ether, glycol ether and amide solvents.
More specifically, examples include acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, and acetonitrile.
Among them, methyl ethyl ketone, tetrahydrofuran, dioxane, N-methylpyrrolidone and the like are more preferable.

The content of the organic solvent is not particularly limited, but is preferably 0.001 to 5.0% by mass, more preferably 0.01 to 2.0% by mass, based on the total mass of the polishing liquid.
One type of organic solvent may be used alone, or two or more types may be used in combination. When two or more organic solvents are used in combination, the total content is preferably within the above range.

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

<Chelating agent>
The polishing liquid may optionally contain a chelating agent (that is, a water softener) in order to reduce the adverse effects of mixed polyvalent metal ions and the like.
As the chelating agent, for example, a general-purpose water softener and / or an analogous compound thereof, which is a calcium and / or magnesium precipitation inhibitor, can be used. If necessary, two or more of these may be used in combination.
The content of the chelating agent may be an amount sufficient to block metal ions such as polyvalent metal ions mixed therein. For example, the content is preferably 0.001 to 2.0% by mass in the total mass of the polishing liquid. .

[Method for producing polishing liquid]
The method for producing the polishing liquid is not particularly limited, and a known production method can be used. As a method for producing a polishing liquid, for example, a method of mixing abrasive grains, an organic acid, and alcohol A is exemplified. At this time, other components, for example, an azole compound, an oxidizing agent, a charge controlling agent, a surfactant, an organic solvent, water, and a chelating agent may be mixed.
When mixing the above components, the order of mixing the components is not particularly limited. For example, an embodiment in which a mixture in which abrasive grains and alcohol A are mixed in advance is prepared, and other components are added to the mixture, or a mixture in which abrasive grains and water are mixed in advance is prepared. Then, an embodiment in which alcohol A and other components are added to the above mixture may be employed.
There is no particular limitation on the method of making alcohol A a predetermined amount based on the total mass of the polishing liquid. As the above-mentioned method, for example, the polishing liquid may be added in a predetermined amount with respect to the total mass of the polishing liquid. When the raw material containing each component also contains alcohol A in advance, 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. By adjusting such factors, the above polishing liquid can be produced.

  As another embodiment of the method for producing a polishing liquid, a method for producing a polishing liquid by adding an oxidizing agent (for example, hydrogen peroxide) to a polishing liquid stock solution in which components other than the oxidizing agent are mixed in advance before producing the polishing liquid. Is mentioned. According to this manufacturing method, in order to obtain a polishing liquid by mixing an oxidizing agent with a stock solution containing a predetermined component, the content of the oxidizing agent with respect to the total mass of the polishing liquid is controlled within a desired range. Cheap. This is because some oxidizing agents decompose with the passage of time and change the content in the polishing liquid.

  In another embodiment of the method for producing a polishing liquid, a concentrated liquid of the 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 to the concentrated liquid. For producing a polishing liquid having the following characteristics:

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

(Polishing object)
Examples of the object to be polished by the above-described 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 polishing object, for example, a barrier metal film (barrier metal layer) formed entirely on the surface of an interlayer insulating film (interlayer insulating layer) having a concave portion, and a concave portion formed on the surface of the barrier metal film so as to fill the concave portion And a conductive film (conductive layer) made of copper or a copper alloy. Such a substrate is typically a semiconductor substrate, and is preferably an LSI having a wiring made of copper metal and / or a copper alloy, and particularly preferably the wiring is a copper alloy.
Examples of the object to be polished include semiconductor devices such as a wafer having a conductive material film formed on a substrate, and a laminate having a conductive material film formed on an interlayer insulating film provided on wiring formed on the substrate. Materials at all stages of the manufacturing process that require planarization can be used.

  Further, among the copper alloys, a copper alloy containing silver is preferable. The copper content of the copper alloy is preferably 40% by mass or less, more preferably 10% by mass or less, still more preferably 1% by mass or less, and is in the range of 0.00001 to 0.1% by mass. The most excellent effect is exerted on the layers.

<Substrate>
Examples of the substrate include those used in an 8-inch or 12-inch semiconductor wafer manufacturing process or a micromachine manufacturing process. The types include a silicon wafer for semiconductors, a silicon-on-insulator (SOI) wafer, and a sapphire substrate of a compound semiconductor used for a semiconductor laser or the like. In addition, it is also used for forming a wiring pattern on a polymer film substrate and then flattening the pattern formation surface.
The target wafer to be subjected to CMP with the polishing liquid preferably has a diameter of 200 mm or more, particularly preferably 300 mm or more.

<Interlayer insulating film>
The interlayer insulating film preferably has a dielectric constant of 2.6 or less, and includes, for example, silicon nitride or polysilicon. In addition. The thickness of the interlayer insulating film can be appropriately adjusted according to the upper and lower portions of the wiring in the multilayer wiring or between generations (nodes).

<Barrier metal film>
The barrier metal film is a film (layer) that is 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 gold layer film is preferably a low-resistance metal material, and specifically includes at least one selected from tantalum, a tantalum compound, titanium, a titanium compound, tungsten, a tungsten compound, and ruthenium. It is preferable that TiN, TiW, Ta, TaN, W, WN, or Ru be included. Note that the thickness of the barrier metal film is preferably about 20 to 30 nm.

The object to be polished used in the CMP method according to the above embodiment can be manufactured, for example, by the following method.
First, an interlayer insulating film such as silicon nitride or polysilicon is laminated on a silicon substrate. Next, by a known means such as formation of a resist layer and etching, a concave portion (substrate exposed portion) of a predetermined pattern is formed on the surface of the interlayer insulating film to form an interlayer insulating film including a convex portion and a concave portion. Tungsten or a tungsten compound is formed on the interlayer insulating film by vapor deposition or CVD (chemical vapor deposition) as a barrier layer covering the interlayer insulating film along the irregularities on the surface. 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) that covers the barrier layer so as to fill the concave portions. Obtain a polished body. The thicknesses of the interlayer insulating film, the barrier layer, and the copper layer are preferably about 0.01 to 2.0 μm, about 1 to 100 nm, and about 0.01 to 2.5 μm, respectively.

[Polishing device]
The polishing apparatus that can perform the above-described CMP method is not particularly limited, and a known chemical mechanical polishing apparatus (hereinafter, also referred to as “CMP apparatus”) can be used.
As the CMP apparatus, for example, a holder for holding an object to be polished (for example, a semiconductor substrate or the like) having a surface to be polished, and a polishing apparatus to which a polishing pad is attached (a motor or the like whose rotation number can be changed) is attached. A general CMP apparatus including a board can be used. As a commercially available product, for example, Reflexion (manufactured by Applied Materials) can be used.

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

<Rotation speed of polishing platen>
In the CMP method according to the above embodiment, polishing is preferably performed at a rotation speed of the polishing platen of 50 to 200 rpm, and more preferably at 60 to 150 rpm.
In order to relatively move the polishing body and the polishing pad, the holder may be further rotated and / or rocked, the polishing table may be rotated in a planetary manner, or the belt-shaped polishing pad may be elongated. It may be moved linearly in one direction. Note that 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 relatively moved.

<How to supply polishing liquid>
In the CMP method according to the above embodiment, while polishing the surface to be polished, the polishing liquid is continuously supplied to the polishing pad on the polishing platen by a pump or the like. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the polishing liquid. The mode of the polishing liquid is as described above.

  Hereinafter, the present invention will be described in more detail based on examples. Materials, usage amounts, 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. Therefore, the scope of the present invention should not be construed as being limited by the following examples. Unless otherwise specified, “%” means “% by mass”.

[Example 1]
The components shown below were mixed to prepare a chemical mechanical polishing solution.
-Colloidal silica (average primary particle diameter: 35 nm, product name "PL3", corresponding to abrasive grains manufactured by Fuso Chemical Co., Ltd.) 0.1% by mass
Glycine (corresponding to organic acids and amino acids) 1.5% by mass
-5-methylbenzotriazole (corresponding to an azole compound containing a benzotriazole skeleton) 0.001% by mass
-3-amino-1,2,4-triazole (corresponding to a compound not containing a benzotriazole skeleton and a compound containing a 1,2,4-triazole skeleton) 0.2% by mass
-Hydrogen peroxide (corresponding to oxidizing agent) 1.0% by mass
-Ammonium nitrate (corresponding to a charge control agent) 1000 mass ppm
・ Methanol (corresponding to alcohol A) 500ppm
・ Water (pure water)

[Examples 2 to 54, Comparative Examples 1 to 5]
The components shown in Table 1, Table 2, Table 3 and Table 4 were mixed in the same manner as in Example 1 to obtain polishing liquids. In addition, each symbol in Table 1 shows the following compounds and the like. Note that “content” in Table 1 represents a value on a mass basis. The pH of each treatment solution was adjusted to the target pH by adding KOH / H ₂ SO ₄ .
PL3 (colloidal silica, product name "PL3", manufactured by Fuso Chemical Co., Ltd., average primary particle diameter: 35 nm, corresponding to abrasive grains)
Gly (corresponds to glycine, organic acids and amino acids)
Ala (corresponds to alanine, organic acids and amino acids)
Asp (corresponds to aspartic acid, organic acid and amino acid)
NMG (corresponds to N-methylglycine, organic acids and amino acids)
・ MaloA (corresponds to malonic acid and organic acid)
-5-MBTA (corresponds to 5-methylbenzotriazole, an azole compound containing a benzotriazole skeleton)
-BTA (corresponding to benzotriazole, an azole compound having a benzotriazole skeleton)
5,6-DMBTA (corresponds to 5,6-dimethylbenzotriazole, an azole compound having a benzotriazole skeleton)
-5-ABTA (corresponds to 5-aminobenzotriazole, an azole compound containing a benzotriazole skeleton)
-3-AT (corresponding to an azole compound containing no 3-amino-1,2,4-triazole or benzotriazole skeleton and an azole compound containing a 1,2,4-triazole skeleton)
Triaz (corresponding to an azole compound containing no 1,2,4-triazole or benzotriazole skeleton and an azole compound containing a 1,2,4-triazole skeleton)
-3,5-DP (corresponding to an azole compound containing no 3,5-dimethylpyrazole or benzotriazole skeleton)
Pyraz (corresponds to an azole compound containing no pyrazole or benzotriazole skeleton and a pyrazole compound containing a pyrazole skeleton)
-Imidaz (corresponds to imidazole, an azole compound containing no benzotriazole skeleton, and an azole compound containing an imidazole skeleton)
-5-ATZ (corresponding to an azole compound containing no 5-aminotetrazole or benzotriazole skeleton)
Am-Ni (corresponds to ammonium nitrate, charge control agent)
-Am-Bz (corresponds to ammonium benzoate, charge control agent)
-Am-Ci (corresponds to triammonium citrate, a charge control agent)
-RE-610 (product name "Rhodafac RE-610", manufactured by Rhodia, corresponding to a surfactant)
-MD-20 (product name "Surfynol MD-20", manufactured by Air Products Inc., corresponding to a surfactant)
A43-NQ (product name "Takesurf-A43-NQ", manufactured by Takemoto Yushi Co., Ltd., corresponding to an anionic surfactant)
-S-465 (product name "Surfynol 465", manufactured by Airproducts, corresponding to a nonionic surfactant)
-DBSH (corresponds to dodecylbenzene sulfonic acid, surfactant)
-MeOH (corresponds to methanol and alcohol A)
HEDP (corresponds to 1-hydroxyethylidene-1,1-diphosphonic acid, organic acid)
・ DTPA (corresponds to diethylenetriaminepentaacetic acid, organic acid)
-PHEAA: N- (2-hydroxyethyl) acrylamide polymer (corresponding to a hydrophilic polymer having a weight average molecular weight of 20,000)
-PEIEO: polyethyleneimine having an ethyleneoxy chain having a repeating unit represented by the following, HLB value 18, n number: 20 (corresponding to a hydrophilic polymer)

(Evaluation of temporal stability of polishing liquid)
The change in the aggregation state of each of the prepared polishing liquids was measured using Turbiscan (Tarviscan MA2000, manufactured by Seishin Enterprise Co., Ltd.). 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 to 4. In addition, C or more is practically preferable.
A: The change in transmitted light intensity before and after storage is 1% or less.
B: Change in transmitted light intensity before and after storage is more than 1% and 3% or less.
C: 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]
A BLANKET Cu wafer was polished using each polishing solution, and the polished Cu wafer was washed with pure water and then dried. The dried Cu wafer was observed using an optical microscope, and the condition of the polished surface of the Cu wafer was evaluated based on the following evaluation criteria. The results are shown in Tables 1 to 4. In addition, C or more is practically preferable.
A: Total number of defects (defect number / Cu wafer) is 3 or less B: Total number of defects is 4 or more and 5 or less C: Total number of defects is 6 or more and 10 or less D: Total number of defects 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 potentiometer (ELSZ-2000ZS, manufactured by Otsuka Electronics Co., Ltd.). The results are shown in Tables 1 to 4.

[Evaluation of polishing rate and dishing]
Polishing was performed while supplying a polishing liquid to the polishing pad under the following conditions, and the polishing rate and dishing were evaluated.
-Polishing device: Reflexion (manufactured by Applied Materials)
・ Polishing object (wafer):
(1) For polishing rate calculation;
Copper: 300 mm diameter blanket wafer with a 1.5 μm thick Cu film formed on a silicon substrate Tungsten: 300 mm diameter blanket wafer with a 0.2 μm thick W film formed on a silicon substrate Silicon nitride: thickness on a silicon substrate Blanket wafer of 300 mm diameter formed with a 1.5 μm silicon nitride film Polysilicon: Blanket wafer of 300 mm diameter formed with a 1.5 μm thick polysilicon film on a silicon substrate (2) For dishing evaluation;
-Copper: Copper wiring wafer (pattern wafer) with a diameter of 300 mm (mask pattern 754 CMP (ATDF))
Tungsten: Tungsten wiring wafer (pattern wafer) with a diameter of 300 mm (mask pattern 754 CMP (ATDF))
-Silicon nitride: silicon nitride wiring wafer (pattern wafer) with a diameter of 300 mm (mask pattern 754 CMP (ATDF))
・ Polysilicon: Polysilicon wiring wafer (pattern wafer) with a diameter of 300 mm (mask pattern 754 CMP (ATDF))
・ Polishing pad: IC1010 (Rodale)
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, meaning pound-force per square inch). Is intended.)
Polishing liquid supply rate: 200 ml / min
Polishing platen rotation speed: 110 rpm
Polishing head rotation speed: 100 rpm

(Evaluation method)
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 evenly spaced locations on the wafer surface, and the polishing time was calculated. The average value of the values obtained by dividing by was defined as the polishing rate, and evaluated according to the following criteria. The results are shown in Tables 1 to 4. Note that the polishing rate is preferably C or higher in practical use.
-Copper (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 not less than 20 nm / min 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.

-Polysilicon (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: In addition to the time until the copper in the non-wiring portion is completely polished, the pattern wafer of (2) is further polished by 25% of the time, and the line and space portion (line A step of 10 μm and a space of 10 μm) was measured using a Dektak V320Si (Veeco) contact-type step meter and evaluated according to the following criteria. The results are shown in Tables 1 to 4. Note that practically, a rating of G or more is preferable.
A: The dishing is 15 nm or less.
B: The dishing is more than 15 nm and not more than 20 nm.
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: The dishing exceeds 45 nm.

(Table 1) In Example 1, the composition of the polishing liquid according to each Example and Comparative Example was described in Table 1 (Part 1) [1] to [3] for each row. For example, the polishing liquid of Example 1 contains 0.1% by mass of PL3 as abrasive grains (the same applies to the total mass of the polishing liquid, the same applies hereinafter), and 1.5% by mass of Gly as an organic acid. Containing 0.001% by mass and 0.2% by mass of 5-MBTA and 3-AT as anticorrosives, 1.0% by mass of H ₂ O ₂ as an oxidizing agent, and Am as a charge control material, respectively. -Contains 1000 mass ppm of Ni, 500 mass ppm of MeOH as alcohol A, and the remainder is water. The pH was 7, the content ratio of the content of alcohol A to each component was 0.50 for the abrasive, 0.033 for the organic acid, 0.25 for the anticorrosive (total), and oxidized. 0.050 for the agent, 0.50 for the charge control agent, the zeta potential was -45 mV, the stability over time was "A", the Cu polishing rate was 375 nm / min, and the evaluation was "B". The dishing was 17 nm, the evaluation was "B", and the defect performance was "A".
The same applies to Table 2 and Tables 2 to 4.

[Example 55]
A polishing liquid according to Example 55 was prepared in the same manner as in Example 1 except that ethanol was used instead of methanol, and the same evaluation was performed as described above. there were.

[Example 56]
A polishing liquid according to Example 56 was prepared and evaluated in the same manner as in Example 1 except that 1-propanol was used instead of methanol. It was a result.

[Example 57]
A polishing liquid according to Example 57 was prepared in the same manner as in Example 1 except that isopropanol was used in place of methanol, and the same evaluation as above was performed. there were.

[Example 58]
Polishing according to Example 58 was performed in the same manner as in Example 1, except that the abrasive was changed from PL3 to PL2 (colloidal silica, product name “PL2”, manufactured by Fuso Chemical Co., Ltd., average primary particle diameter: 25 nm). A liquid was prepared and evaluated in the same manner as described above. The result was the same as that in Example 1.

From the results shown in Table 1, it is found that the polishing liquid for chemical mechanical polishing contains abrasive grains, an organic acid, and alcohol A, wherein alcohol A is methanol, ethanol, 1-propanol, and isopropanol. The polishing liquids of Examples 1 to 41, which are at least one selected from the group consisting of: the content of alcohol A is 1.0 to 800 ppm by mass based on the total mass of the polishing liquid, Had.
On the other hand, the polishing liquids of Comparative Examples 1 to 4 did not have the desired effects.
In addition, the polishing liquids of Examples 1, 3, and 4 in which the content mass ratio of the alcohol A to the organic acid was 0.001 to 0.05 were superior to the polishing liquid of Example 2 with respect to time. It had stability, and when applied to CMP, the generation of defects was further suppressed. In addition, it had more excellent polishing rate and dishing performance.
The polishing liquid had a higher polishing rate and dishing performance than the polishing liquid of Example 5.
In addition, the polishing liquids of Examples 1, 39 and 40 in which the content of the charge control agent is 10 to 1000 ppm by mass, when compared to the polishing liquid of Example 38, had defects when applied to CMP. More restrained. On the other hand, the polishing liquid had better temporal stability than the polishing liquid of Example 37, and the generation of defects was more suppressed when applied to CMP.
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 was 0.1 to 50 was compared with the polishing liquid of Example 41. More excellent stability over time, and the occurrence of defects was further suppressed when applied to CMP. Moreover, it had a more excellent polishing rate. On the other hand, the polishing liquid had better temporal stability than the polishing liquid of Example 38, and the generation of defects was more suppressed when applied to CMP.
Further, the polishing liquids of Examples 11, 1, and 12 having a pH of 5.0 to 8.0 have better temporal stability than the polishing liquid of Example 10, and have a higher CMP stability. When it was applied, the generation of defects was further suppressed. On the other hand, the above polishing liquid had more excellent dishing performance than the polishing liquid of Example 13.
In addition, the polishing liquids of Examples 1 and 15, in which the content of the organic acid was 1.0 to 20% by mass, had a more excellent polishing rate than the polishing liquid of Example 14. . On the other hand, the polishing liquid had more excellent dishing performance than the polishing liquid of Example 16.

Claims (22)

A polishing liquid for chemical mechanical polishing containing abrasive grains, an organic acid, and alcohol A,
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,
Furthermore, it contains two or more azole compounds,
A polishing liquid comprising, as the two or more azole compounds, a benzotriazole compound and an azole compound different from the benzotriazole compound.   The method according to claim 1, further comprising a charge control agent, wherein the charge control agent comprises at least one selected from the group consisting of inorganic acids, ammonium salts of organic acids, and ammonium salts of inorganic acids. Polishing liquid. A polishing liquid for chemical mechanical polishing containing abrasive grains, an organic acid, and alcohol A,
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 polishing liquid further comprises a charge control agent, wherein 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. Wherein the charge control agent, ammonium salts of organic acids, ammonium sulfate, which contains at least one member selected from the group consisting of ammonium hydrochloride, and ammonium nitrate, the polishing liquid according to claim 2 or 3. The polishing liquid according to any one of claims 2 to 4 , wherein a content of the charge control agent is 10 to 1000 ppm by mass with respect to a total mass of the polishing liquid. The polishing liquid according to any one of claims 2 to 5 , wherein a content ratio by mass of the alcohol A to the charge control agent is 0.1 to 50.   The polishing liquid according to any one of claims 1 to 3, wherein the organic acid is an amino acid. The amino acid is glycine, alanine, arginine, isoleucine, leucine, valine, phenylalanine, asparagine, glutamine, lysine, histidine, proline, tryptophan, aspartic acid, glutamic acid, serine, threonine, tyrosine, cysteine, methionine, and N-methylglycine. The polishing liquid according to claim 7 , wherein the polishing liquid is at least one selected from the group consisting of: The polishing liquid according to claim 7 , wherein the polishing liquid contains two or more kinds of the amino acids. The polishing liquid according to any one of claims 1 to 9 , wherein a content ratio of the alcohol A to the organic acid is from 0.001 to 0.05. The polishing liquid according to any one of claims 1 to 10 , wherein the content of the organic acid is 1.0 to 20% by mass based on the total mass of the polishing liquid. The polishing liquid according to claim 3, further comprising two or more azole compounds. The polishing liquid according to claim 12 , wherein the two or more azole compounds include a benzotriazole compound and an azole compound different from the benzotriazole compound. Different azole compound and the benzotriazole compound is 1,2,4-triazole compound is at least one selected pyrazole compounds, and from the group consisting of imidazole compounds, according to claim 1, or, according to 13 Polishing liquid. The content of the alcohol A is 1.0 to 500 mass ppm in the total mass of the polishing liquid,
The polishing liquid according to any one of claims 1 to 14 , wherein a content mass ratio of the content of the alcohol A to the content of the abrasive grains is 0.1 to 0.7. The polishing liquid according to any one of claims 1 to 15 , wherein the polishing liquid has a pH of 5.0 to 8.0. Further contains an oxidizing agent, polishing liquid according to any one of claims 1-16. 18. The polishing liquid according to claim 17 , wherein the polishing liquid contains two or more oxidizing agents. 19. The polishing according to claim 17 or 18 , comprising at least one first oxidizing agent selected from the group consisting of hydrogen peroxide and peroxide and a second oxidizing agent which is an iron (III) salt. liquid. The polishing liquid according to any one of claims 1 to 19 , wherein the abrasive is colloidal silica. A polishing pad according to any one of claims 1 to 20 is supplied to a polishing pad attached to a polishing platen to bring a surface to be polished of the object to be polished into contact with the polishing pad. And a step of relatively moving the polishing pad to polish the surface to be polished to obtain a polished object to be polished. 22. The chemical mechanical polishing method according to claim 21 , wherein the object to be polished includes at least one layer selected from the group consisting of copper, copper alloy, tungsten, tungsten alloy, silicon nitride, and polysilicon.