TW201742898A - Polishing liquid and chemical mechanical polishing method - Google Patents

Abstract

The present invention addresses the issue of providing a polishing liquid whereby abrasive grains in the polishing liquid are unlikely to agglomerate and, even when used in CMP, defects are less likely to occur in a polished surface. The present invention also addresses the issue of providing a chemical mechanical polishing method. This polishing liquid is used for chemical mechanical polishing and contains abrasive grains, an organic acid, and alcohol A. The alcohol A is at least one type selected from the group consisting of methanol, ethanol, 1-propanol, and isopropanol. The alcohol A content is 1.0-800 ppm by mass of the total mass of the polishing liquid.

Description

Grinding liquid and chemical mechanical polishing method

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

In the manufacture of a semiconductor integrated circuit (LSI), chemical mechanical polishing (CMP) is used for planarization of bare wafers, planarization of interlayer insulating films, formation of metal plugs, and formation of buried wirings. :chemical mechanical polishing method. For example, Patent Document 1 discloses "a polishing liquid characterized by containing an alcohol, abrasive grains, and water having a solubility in water of 0.5 to 8% by weight at a liquid temperature of 25 degrees. ". [Prior Technical Literature] [Patent Literature]

[Patent Document 1]: JP-A-2004-74175

As a result of examining the polishing liquid described in Patent Document 1, the inventors have found that there is a problem that the abrasive grains contained in the polishing liquid are easily aggregated when the polishing liquid is stored. Further, it has been clarified that when the polishing liquid is used for CMP, there is a problem that defects are likely to occur on the surface to be polished of the object to be polished.

An object of the present invention is to provide a polishing liquid which is less likely to aggregate (in other words, "excellent stability with time"), and in the case of use in CMP, defects are not easily generated on the surface to be polished (in other words, " Scratch"). Further, the subject of the present invention is to provide a chemical mechanical polishing method.

As a result of intensive studies to achieve the above-described problems, the present inventors have found that the polishing liquid can be used to solve the above problems, and the polishing liquid contains chemical particles for polishing abrasive grains, organic acids, and predetermined alcohols A. The content of the slurry and the alcohol A is within a predetermined range. That is, it is understood that the above problem can be achieved by the following configuration.

[1] A polishing liquid comprising a polishing liquid for chemical mechanical polishing of an abrasive grain, 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 isopropyl alcohol. The content of the 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 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] which further contains a charge adjuster containing at least one selected from the group consisting of an inorganic acid, an ammonium salt of an organic acid, and an ammonium salt of a mineral acid. Kind. [4] The polishing liquid according to [3], wherein the content of the charge control agent is 10 to 1000 ppm by mass based on the total mass of the polishing liquid. [5] The polishing liquid according to [3] or [4], wherein the mass ratio of the alcohol A to the charge adjusting 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 polishing liquid according to [6], wherein the amino acid is selected from the group consisting of glycine, alanine, arginine, isoleucine, leucine, lysine, phenylalanine, aspartame Indamine, glutamine, lysine, histidine, valine, tryptophan, aspartic acid, glutamic acid, serine, threonine, tyrosine, cysteine, At least one of the group consisting of methionine and N-methylglycine. [8] The polishing liquid according to [6] or [7] which contains two or more kinds of amino acids. [9] The polishing liquid according to any one of [1] to [8] wherein the pH of the polishing liquid is 5.0 to 8.0. [10] The polishing liquid according to any one of [1] to [9] which further contains an oxidizing agent. [11] The polishing liquid according to [10], which contains two or more kinds of oxidizing agents. [12] The polishing liquid according to any one of [1] to [11] which further contains two or more kinds of 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. Kind. [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 granular colloidal cerium oxide is ground. [17] A chemical mechanical polishing method comprising the polishing liquid according to any one of [1] to [16], wherein the polishing liquid is attached to the polishing pad, and the polishing body is The polishing surface is brought into contact with the polishing pad, and the polishing body and the polishing pad are relatively moved to polish the surface to be polished, thereby obtaining a polished object to be polished. [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, tantalum nitride, and polycrystalline germanium. [Effect of the invention]

According to the present invention, it is possible to provide a polishing liquid which has excellent stability over time and which is less likely to cause defects on the surface to be polished when used in CMP (hereinafter, also referred to as "having the effect of the present invention" ".). Further, according to the present invention, it is also possible to provide a chemical mechanical polishing method.

Hereinafter, the present invention will be described in detail based on the embodiments. In addition, since the description of the components described below is completed according to the embodiment of the present invention, the present invention is not limited to the embodiments. In the present specification, the numerical range expressed by "to" means a range including the numerical values described before and after "~" as the lower limit and the upper limit.

[Polishing liquid] The polishing liquid according to an embodiment of the present invention contains polishing liquid for chemical mechanical polishing of abrasive grains, organic acids and alcohol A, and the alcohol A is selected from the group consisting of methanol, ethanol, 1-propanol and isopropanol. At least one of the groups, the content of the alcohol A is 1.0 to 800 ppm by mass based on the total mass of the polishing liquid. In addition, in the present specification, ppm means parts per million.

[Alcohol A (Alc)] One of the characteristics of the polishing liquid is a characteristic point in which the content of the 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, it is estimated that the absolute value of the zeta potential on the surface of the abrasive grain (especially the surface of the colloidal ceria) is lowered, and the abrasive grains are easily aggregated in the polishing liquid during storage, and the time is lapsed. Reduced stability. On the other hand, when the content of the above alcohol A is less than the lower limit, when the polishing liquid is used in CMP, defects are likely to occur on the surface to be polished of the object to be polished.

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

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

In addition, in this specification, the content of the alcohol A in the polishing liquid means the content measured by the following method. The content of the alcohol A in the slurry was determined by gas chromatography. The measurement conditions of the gas chromatography were as follows. Further, in the case where the ratio of the components of the polishing liquid is clear, the alcohol A content can be determined from the ratio of the alcohol A to the total mass of the polishing liquid, and the above measurement can be used.

- Gas chromatography: 7890 series manufactured by Agilent Technologies, Inc. Temperature rise conditions: initial temperature 40 ° C, temperature increase rate 10 ° C / min and temperature rise to 250 ° C ・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 gas 1.0 mL/min, injection port temperature: 250 ° C • Hydrogen flame ion detector temperature: 300 ° C

(pH) The pH of the polishing liquid is not particularly limited, and is usually 1.0 to 14.0. Among them, 5.0 to 8.0 is more preferable. When the pH is 5.0 or more, a polishing liquid having more excellent stability over time can be obtained, and when the polishing liquid is used in CMP, defects are less likely to occur on the surface to be polished. Although the mechanism by which this effect can be obtained is not necessarily clear, the inventors can estimate that, for example, the isoelectric point of the zeta potential on the surface of the colloidal ceria is close to pH 4.0, and therefore, by adjusting the pH of the slurry to be larger than the above, etc. Within the above range of electrical points, the abrasive grains are less likely to agglomerate. On the other hand, when the pH is 8.0 or less, when the polishing liquid is used for CMP, it is less likely to cause dishing on the surface to be polished of the object to be polished.

[Abrasive Grain (A)] The polishing liquid contains abrasive grains. The abrasive grains are not particularly limited, and known abrasive grains can be used. Examples of the abrasive grains include inorganic abrasive grains such as cerium oxide, aluminum oxide, zirconium oxide, cerium oxide, titanium oxide, cerium oxide, and cerium carbide; and organic abrasive grains such as polystyrene, polyacrylic acid, and polyvinyl chloride. Among them, the cerium oxide particles are preferably used as the abrasive grains from the viewpoint of excellent dispersion stability in the polishing liquid and a small amount of polishing scratches (scratches) generated by CMP. The cerium oxide particles are not particularly limited, and examples thereof include precipitated cerium oxide, gas phase cerium oxide, and colloidal cerium oxide. Among them, colloidal cerium oxide is more preferable.

The average primary particle diameter of the abrasive grains is not particularly limited, but from the viewpoint of more excellent dispersion stability of the polishing liquid, 1 to 100 nm is preferable. Further, the above average primary particle diameter can be confirmed by a manufacturer's product catalog or the like. As a commercially available product of the above-mentioned abrasive grains, for example, PL-1, PL-2, PL-3, PL-7, and PL-10H are exemplified as colloidal cerium oxide (all are trade names, FUSO CHEMICAL CO., LTD) .)).

The content of the abrasive grains is not particularly limited, and is preferably 0.01% by mass or more based on the total mass of the polishing liquid, more preferably 0.1% by mass or more, more preferably 10% by mass or less, and still more preferably 5% by mass or less. If it is in the above range, when the polishing liquid is used in CMP, a more excellent polishing rate can be obtained. In addition, one type of the abrasive grains may be used alone or two or more types may be used in combination. When two or more kinds of abrasive grains are used in combination, the total content is preferably in the above range.

It is preferable that the following relationship is satisfied between the content of the abrasive grains and the content of the above alcohol A. That is, the mass ratio of the content of the above alcohol A to the content of the abrasive grains (the content of the alcohol A/the content of the abrasive grains; also referred to as the "Alc/A" ratio) is preferably 0.0001 to 1.5, preferably 0.01 to 0.08. More preferably, 0.1 to 0.7 is further preferred. When the Alc/A ratio is 0.1 to 0.7, when the polishing liquid is used in CMP, a more excellent polishing rate can be obtained.

[Organic Acid (B)] The above polishing liquid contains an organic acid. The organic acid is a compound different from the oxidizing agent and the charge adjusting agent described later, and has an effect of promoting oxidation of the metal, pH adjustment of the polishing liquid, and acting as a buffer. As the organic acid, a water-soluble organic acid is preferred. The organic acid is not particularly limited, and a known organic acid can be used. The organic acid may, for example, be 1-hydroxyethylidene-1,1-diphosphonic acid (hereinafter also referred to as "HEDP") or 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, positive Heptanoic acid, 2-methylhexanoic 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, hydroxyethylimine diacetic acid, and iminodiacetic acid.

As the organic acid, an amino acid is more preferable from the viewpoint of having more excellent water solubility. The amino acid is not particularly limited, and a 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, and day. Winter amide, glutamine, lysine, histidine, valine, tryptophan, aspartic acid, glutamic acid, serine, threonine, tyrosine, cysteine , methionine and N-methylglycine. Among them, according to the viewpoint that the polishing liquid has more excellent effects of the present invention, as the amino acid, glycine, α-alanine, β-alanine, L-aspartic acid or methylglycine (N- Methylglycine is preferred, and glycine and/or methylglycine are more preferred. Further, the amino acid may be used singly or in combination of two or more. In the case where two or more kinds of amino acids are used in combination, the total content is preferably in the above range. Among them, the polishing liquid contains two or more kinds of amino acids from the viewpoint of obtaining a polishing liquid having an effect more excellent in the present invention. The two or more kinds of amino acids are not particularly limited, and can be used by combining the above amino acids. In the case where the polishing liquid is used in the CMP, the glycine acid and the two or more kinds of amino acids are used in view of obtaining a more excellent polishing rate and making it less likely to cause dents on the surface to be polished of the object to be polished. Combinations of alanine, alanine and N-methylglycine, 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, even more preferably 1.0% by mass or more, and 50% by mass or less, based on the total mass of the polishing liquid. Preferably, it is more preferably 25% by mass or less, further preferably 20% by mass or less, and particularly preferably 10% by mass or less. When the content of the organic acid is 0.1% by mass or more, when the polishing liquid is used in CMP, a more excellent polishing rate can be obtained. In addition, when the content of the organic acid is 50% by mass or less, when the polishing liquid is used in CMP, the depression is less likely to occur on the surface to be polished. When the content of the organic acid is 1.0 to 20% by mass based on the total mass of the polishing liquid, a polishing liquid having an effect more excellent in the present invention can be obtained. Further, the organic acid may be used singly or in combination of two or more. When two or more types of organic acids are used in combination, the total content is preferably in the above range.

It is preferable that the following relationship is satisfied between the content of the organic acid and the content of the above alcohol A. That is, the mass ratio of the content of the above alcohol A relative to the content of the organic acid (alcohol A content / organic acid content; also referred to as "Alc/B" ratio) is preferably 0.0001 to 0.2, preferably 0.0006 to 0.1. More preferably, 0.001 to 0.05 is further preferred. When the Alc/B ratio is 0.001 to 0.05, when the polishing liquid is used in CMP, a more excellent polishing rate can be obtained.

[Optional Component] The polishing liquid may contain a component other than the above as an optional component. Hereinafter, the arbitrary components will be described.

<Preservative (C)> The above polishing liquid may contain a preservative. The preservative is adsorbed on the surface to be polished of the object to be polished to form a film, and it is preferable to have a function of controlling metal corrosion. The preservative is not particularly limited, and a known preservative can be used. Among them, an azole compound is preferred.

(Azo compound) In the present specification, the azole compound refers to a compound containing a five-membered hetero ring containing one or more nitrogen atoms, and preferably 1 to 4 as the number of nitrogen atoms. Further, the azole compound may contain an atom other than the nitrogen atom as a hetero atom. Further, the above induction system means a compound having a substituent which the above-mentioned five-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 tetrazolium skeleton, an imidazole skeleton, a thiazole skeleton, an oxazole skeleton, and the like. A compound of an oxazole skeleton, a thiadiazole skeleton, an oxadiazole skeleton, and a tetrazolium skeleton. The azole compound may be an azole compound containing a polycyclic structure further containing a condensed ring on the above skeleton. Examples of the azole compound containing the above polycyclic structure include an anthracene skeleton, an anthracene skeleton, a carbazole skeleton, a benzimidazole skeleton, a carbazole skeleton, a benzoxazole skeleton, a benzothiazole skeleton, and a benzothiazide. A compound of a diazole skeleton and a naphthopylimidazole skeleton.

The substituent which may be contained in the azole compound 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 (linear, branched or cyclic alkyl group). It may be a polycyclic alkyl group such as a bicycloalkyl group, or may contain an active methine group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (optional substitution position), a mercapto group, an alkoxycarbonyl group, an aryloxycarbonyl group. A heterocyclic carbonyl group or an aminomethyl fluorenyl group (as an amino group having a substituent, for example, an N-hydroxyaminocarbamyl group, an N-methylaminomethyl fluorenyl group, and an N-sulfonium group) Aminomethylmercapto, N-aminocarbamimidylmethyl, thioaminomethylhydrazine and N-amine sulfonylaminomethyl, etc., carbazolyl, carboxyl or a salt thereof, Alkaloid, oxalylhydrazyl, cyano, carbomino, carbenyl, hydroxy, alkoxy (containing an ethyleneoxy group or a group containing an ethyleneoxy group as a repeating unit), aryloxy , heterocyclic oxy, decyloxy, carbonyloxy, aminomethyl methoxy, sulfonyloxy, amine, decylamino, sulfonylamino, ureido, thioureido, N- Ureyl group, quinone imine group, carbonylamino group, amine sulfonamide group, aminoureido group, thioaminoureido group, mercapto group, ammonium group, oxalylamine group, N-(alkyl or aromatic Sulfhydryl ureido group, N-mercaptoureido group, N-decylamine sulfonamide group, hydroxylamine group, nitro group, heterocyclic group containing a quaternary nitrogen atom (for example, pyridinium group, imidazolyl group) , quinolyl and isoquinolyl), isocyano, imido, fluorenyl, (alkyl, aryl or heterocyclyl)thio, (alkyl, aryl or heterocyclyl) disulfide, (alkyl, aryl)sulfonyl, (alkyl or aryl) sulfinyl, sulfo or a salt thereof, aminesulfonyl (as a sulfonyl group having a substituent, for example, N- Amidoxime sulfonyl group and N-sulfonylamine sulfonyl) or a salt thereof, a phosphino group, a phosphinyl group, a phosphinyloxy group, a phosphinylamino group, a formyl group, and the like. Wherein, 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 such as a bicycloalkyl group may be a polycycloalkyl group, and may also contain an active secondary A base, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group (optional substitution position) is preferred.

Here, the "active methine group" means a methine group substituted with two electron withdrawing groups. "Electron-absorbing group" means, for example, an anthracenyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aminomethylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an aminesulfonyl group, a trifluoromethyl group, a cyano group, Nitro or carbon quinone imine. Further, the two electron withdrawing groups may be bonded to each other to form a ring structure. Further, "salt" means a cation such as an alkali metal, an alkaline earth metal or a heavy metal; an organic cation such as an ammonium ion or a cesium ion.

Specific examples of the azole compound include 5-methylbenzotriazole, 5-aminobenzotriazole, benzotriazole, 5,6-dimethylbenzotriazole, and 3-amine. Base-1,2,4-triazole, 1,2,4-triazole, 3,5-dimethylpyrazole, pyrazole and imidazole.

The content of the azole compound is preferably 0.001 to 1.6% by mass based on the total mass of the polishing liquid. Further, the azole compound may be used alone or in combination of two or more. When two or more kinds of azole compounds are used in combination, the total content is preferably in the above range. Among them, two or more kinds of azole compounds are preferably used in view of the viewpoint of obtaining a polishing liquid having an effect more excellent in the present invention. Further, the respective aspects of the two or more azole compounds are the same as those of the above azole compound.

The benzotriazole compound (compound containing a benzotriazole skeleton) and a benzotriazole compound are different from the viewpoint of obtaining a polishing liquid having an effect more excellent in the present invention as the azole compound. The compound (a compound not containing a benzotriazole skeleton) is preferred.

The compound which does not contain the above-mentioned benzotriazole skeleton is not particularly limited, but is selected from the group consisting of a 1,2,4-triazole compound and a pyrene according to the viewpoint of obtaining a polishing liquid having an effect more excellent in the present invention. At least one of the group of the azole compound and the imidazole compound is preferred.

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

It is preferred that the content of the preservative (C) and the content of the above alcohol A satisfy the following relationship. That is, the mass ratio of the content of the above alcohol A to the content of the preservative (the content of the alcohol A/the content of the preservative; also referred to as the "Alc/C" ratio) is preferably 0.004 or more, more preferably 0.0045 or more. Preferably, 0.01 or more is further more preferable, and 0.03 or more is particularly preferable, 0.04 or more is 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, when the polishing liquid is used in CMP, a more excellent polishing rate can be obtained. Further, when the Alc/C ratio is 0.04 or more, when the polishing liquid is used for CMP, it is less likely to cause dents on the surface to be polished of the object to be polished. On the other hand, when the Alc/C ratio is 5 or less, when the polishing liquid is supplied to the CMP, the depression is less likely to occur on the surface to be polished of the object to be polished.

<Oxidant (D)> The above 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 persulfuric acid. Hydrogen peroxide is more preferred as the salt, dichromate, permanganate, ozone water, silver (II) salt and iron (III) salt. The oxidizing agent may be used alone or in combination of two or more. In the case of CMP which is used for a substrate (the object to be polished) containing at least one layer selected from the group consisting of tungsten and a tungsten alloy, it is used in accordance with the viewpoint of obtaining a polishing liquid having an effect more excellent in the present invention. Two or more kinds of oxidizing agents are preferred.

When two or more types of oxidizing agents are used in combination, it is preferred to use a first oxidizing agent having a higher redox potential and a second oxidizing agent (G) having a lower redox potential. As the first oxidizing agent, for example, at least one selected from the group consisting of hydrogen peroxide and peroxide in the above oxidizing agent is preferred, and hydrogen peroxide is more preferable. As the second oxidizing agent, for example, in the above oxidizing agent, an iron (III) salt is preferred, and at least one selected from the group consisting of ferric nitrate, iron phosphate, iron sulfate, and potassium ferricyanide is more preferable, and ferric nitrate (Fe) (NO ₃ ) ₃ ) is further 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, when the polishing liquid is used in CMP, a more excellent polishing rate can be obtained. When the content of the oxidizing agent is 9.0% by mass or less, when the polishing liquid is used for CMP, it is less likely to cause dents on the surface to be polished. Further, when two or more kinds of oxidizing agents are used in combination, the total content is preferably in the above range.

The following relationship is preferably satisfied between the content of the oxidizing agent and the content of the above alcohol A. That is, the mass ratio of the content of the above 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 the "Alc/D" ratio) is preferably 0.0005 or more, more preferably 0.005 or more. Further, 0.04 or more is further more preferable, and 0.09 or less is preferable, and 0.07 or less is more preferable. When the Alc/D ratio is 0.005 or more, when the polishing liquid is used in CMP, a more excellent polishing rate can be obtained. Further, when the Alc/D ratio is 0.04 or more, when the polishing liquid is used for CMP, it is less likely to cause dents on the surface to be polished of the object to be polished. Further, when the Alc/D ratio is 0.07 or less, a more excellent polishing rate can be obtained when the polishing liquid is used in CMP.

Further, when the first oxidizing agent and the second oxidizing agent are used in combination, the following relationship is preferably satisfied between the content of the second oxidizing agent and the content of the above alcohol A. That is, the mass ratio of the content of the above alcohol A to the content of the second oxidizing agent (the content of the alcohol A / the content of the second oxidizing agent; also referred to as the "Alc/G" ratio) is preferably 0.1 to 20.

<Charge Adjuster (E)> The above polishing liquid may contain a charge adjuster. The charge adjuster is not particularly limited, and a known charge adjuster can be used. The charge control agent has a function 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 adjuster include an acid, a base, and a salt compound. In particular, at least one selected from the group consisting of an inorganic acid, an ammonium salt of an organic acid, and an ammonium salt of a mineral acid is preferred from the viewpoint of a polishing liquid having an effect of the present invention. Examples of the inorganic acid include sulfuric acid, hydrochloric acid, and nitric acid. Further, examples of the ammonium salt of the organic acid include ammonium benzoate and ammonium citrate. Further, examples of the ammonium salt of the inorganic acid include ammonium sulfate, ammonium hydrogen chloride, and ammonium nitrate.

The content of the charge control agent is not particularly limited, and is preferably 0.5 ppm by mass or more, more preferably 1 ppm by mass or more, even more preferably 10 ppm by mass or more, and further preferably 2% by mass or less based on the total mass of the polishing liquid. Preferably, it is more preferably 1200 ppm by mass or less. When the content of the charge control agent is 10 ppm by mass or more, when the polishing liquid is used in 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 used in CMP, a more excellent polishing rate can be obtained, and the surface to be polished is polished. It is less prone to dents. Further, the charge control agent may be used alone or in combination of two or more. When two or more types of charge control agents are used in combination, the total content is preferably in the above range.

It is preferable that the relationship between the content of the charge control agent and the content of the above alcohol A satisfies the following relationship. That is, the mass ratio of the content of the above alcohol A to the content of the charge control agent (ratio of the content of the alcohol A / the content of the charge adjuster; also referred to as the "Alc/E" ratio) is preferably 0.005 or more. More preferably, 0.1 or more is preferable, 500 or less is preferable, 50 or less is more preferable, and less than 5 is further preferable. When the Alc/E ratio is 0.1 or more, a polishing liquid having more excellent stability over time can be obtained, and when the polishing liquid is used in CMP, a more excellent polishing rate can be obtained, and the surface to be polished can be polished. It is less prone to dents. Further, when the Alc/E ratio is 50 or less, when the polishing liquid is used for CMP, defects are less likely to occur on the surface to be polished. Further, when the Alc/E ratio is less than 5, the effect of the present invention which is more excellent can be obtained.

<Surfactant (F)> The above polishing liquid may contain a surfactant. The surfactant has the effect of reducing the contact angle of the polishing liquid phase with respect to the surface to be polished, and the polishing liquid is easily wetted and spread on the surface to be polished. The surfactant is not particularly limited, and a known surfactant selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant can be used. The anionic surfactant may, for example, be a sulfonate such as a carboxylate or an alkylbenzenesulfonic acid, a sulfate salt or a phosphate salt. The cationic surfactant may, for example, be an aliphatic amine salt, an aliphatic quaternary ammonium salt, a benzalkonium chloride salt, benzethonium chloride, a pyridinium salt or an imidazolinium salt. The amphoteric surfactant may, for example, be a carboxybetaine, an aminocarboxylate, an imidazolinium betaine, a lecithin or an 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-based surfactant, and an anthraquinone-based surfactant.

The content of the surfactant is not particularly limited, and is preferably 0.00001 to 2.0% by mass based on the total mass of the polishing liquid, more preferably 0.0001 to 1.0% by mass, still more preferably 0.001 to 0.1% by mass. When the content of the surfactant is in the range of 0.0001 to 1.0% by mass, a polishing liquid having an effect more excellent in the present invention can be obtained. Further, the surfactant may be used singly or in combination of two or more. When two or more kinds of surfactants are used in combination, the total content is preferably in the above range.

It is preferred that the content of the surfactant and the content of the above alcohol A satisfy the following relationship. That is, the mass ratio of the content of the above 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. More preferably, it is 0.002 to 80, and further preferably 0.005 to 50. When the Alc/F ratio is within the above range, a polishing liquid having more excellent defect properties 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 polyethanols such as polyethylene glycol, alkyl ethers of polyethanols, polysaccharides such as polyvinyl alcohol A, polyvinylpyrrolidone, and alginic acid, polymethacrylic acid, and polyacrylic acid. A carboxylic acid-containing polymer, polypropylene decylamine, polymethacrylamide, and polyethylenimine. Specific examples of such a hydrophilic polymer include water-soluble polymers described in paragraphs 004 to 0044 of JP-A-2009-88243 and JP-A-2007-194261.

The hydrophilic polymer is preferably a water-soluble polymer selected from the group consisting of polyacrylamide, polymethacrylamide, polyethylenimine and polyvinylpyrrolidone. As polypropylene decylamine or polymethacrylamide, having a hydroxyalkyl group on a nitrogen atom (for example, N-(2-hydroxyethyl) acrylamide polymer, etc.) or having a substitution comprising a polyalkylene oxide chain The base is preferably a weight average molecular weight of from 2,000 to 50,000. As the polyethylenimine, a polyalkylene oxide chain is preferred on the nitrogen atom, and a repeating unit represented by the following formula is more preferred.

[Chemical Formula 1]

In the above formula, n represents a number of from 2 to 200 (the average of the mixture in the case of a mixture). Further, it is preferred that the polyethylenimine has an HLB (Hydrophile-Lipophile Balance) value of 16 to 19.

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

<Organic solvent> The above 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. Further, the above organic solvent is different from the component of the alcohol A which has been described. Examples of the organic solvent include a ketone system, an ether system, a glycol ether system, and a guanamine solvent. More specifically, for example, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, dimethylacetamide, N-methylpyrrolidone, dimethyl hydrazine, acetonitrile or the like can be given. Among them, methyl ethyl ketone, tetrahydrofuran, dioxane, and N-methylpyrrolidone are more preferred.

The content of the organic solvent is not particularly limited, and 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. In addition, one type of the organic solvent may be used alone or two or more types may be used in combination. When two or more types of organic solvents are used in combination, the total content is preferably in the above range.

<Water> It is preferred that the polishing liquid contains water. The water contained in the polishing liquid is not particularly limited, and ion-exchanged water or pure water can be used. The content of water is not particularly limited, and is usually preferably from 90 to 99% by mass based on the total mass of the polishing liquid.

<Chelating Agent> The polishing liquid may contain a chelating agent (that is, a hard water softening agent) as needed to reduce the adverse effects of the polyvalent metal ions to be mixed. As the chelating agent, for example, a general hard water softening agent which is a suspending agent for calcium and/or magnesium and/or a similar compound can be used, and two or more of the above substances can be used in combination as needed. The content of the chelating agent may be a sufficient amount when the metal ions such as the polyvalent metal ions to be mixed are sequestered. For example, it is preferably 0.001 to 2.0% by mass based on 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 of producing the polishing liquid, for example, a method of mixing the abrasive grains, the organic acid, and the alcohol A can be mentioned. In this case, other components such as an azole compound, an oxidizing agent, a charge control agent, a surfactant, an organic solvent, water, and a chelating agent may be mixed. Moreover, the order of mixing each of the above components is not particularly limited. For example, it may be in the following manner: preparing a mixture in which the abrasive grains and the alcohol A are previously mixed, and adding other components to the above mixture, or in the following manner: preparing a mixture in which the abrasive grains and water are mixed in advance, and adding the alcohol to the above mixture A and other ingredients. The method of setting the alcohol A to a predetermined amount with respect to the total mass of the polishing liquid is not particularly limited. The above method can be added, for example, so as to be a predetermined amount with respect to the total mass of the polishing liquid. In addition, when the raw material containing each component contains the alcohol A in advance, if the total amount of the alcohol A contained in the raw material is adjusted to a predetermined amount with respect to the total mass of the polishing liquid, the mixing ratio of the raw materials can be adjusted. The above slurry was produced.

In another aspect of the method for producing a polishing liquid, a method of preparing an abrasive by adding an oxidizing agent (for example, hydrogen peroxide) to a polishing liquid stock in which components other than the oxidizing agent are previously mixed is prepared. liquid. According to this production method, since the polishing liquid is obtained by mixing an oxidizing agent with a 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 within a desired range. The reason for this is that there is a case where the oxidizing agent is decomposed over time and the content in the polishing liquid changes.

In addition, as another aspect of the method for producing the polishing liquid, a method of preparing a concentrated liquid containing a polishing liquid having a predetermined component, and adding at least one selected from the group consisting of an oxidizing agent and water, and having a specification are provided. The characteristics of the slurry.

[Chemical Mechanical Polishing Method] The chemical mechanical polishing method according to an embodiment of the present invention includes a chemical mechanical polishing method (hereinafter also referred to as "CMP method") which is a process (hereinafter also referred to as "polishing process"). A polishing pad attached to the polishing table is supplied with the polishing liquid, and 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 relatively moved to polish the surface to be polished, thereby obtaining the ground surface. The body to be polished.

[The object to be polished] The object to be polished which is polished by the CMP method includes a layer containing at least one layer selected from the group consisting of copper, a copper alloy, tungsten, a tungsten alloy, tantalum nitride, and polycrystalline germanium. . The object to be polished is, for example, a substrate having a barrier metal film (barrier metal layer) formed on one surface of an interlayer insulating film (interlayer insulating layer) having a recess; and a conductor film (conductor layer) including a recessed portion A copper or copper alloy formed in such a manner as to block the surface of the metal film. A typical semiconductor substrate in such a substrate is preferably an LSI including wiring of copper metal and/or copper alloy, and particularly a wiring-based copper alloy. Examples of the object to be polished include materials which are required to be planarized in a semiconductor device manufacturing process: a wafer on which a conductive material film is formed on a substrate, and an interlayer insulating film provided on a wiring formed on the substrate. A laminate or the like having a film of a conductive material is formed.

Further, a copper alloy containing silver in a copper alloy is preferred. The content of silver contained in 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 most preferably the copper alloy layer in the range of 0.00001 to 0.1% by mass. Excellent results.

<Substrate> Examples of the substrate include a user in an 8-inch or 12-inch semiconductor wafer manufacturing process or a micro-machine manufacturing process. The type thereof includes a semiconductor wafer, an SOI (Silicon-On-Insulator) wafer, or a sapphire substrate of a compound semiconductor used in a semiconductor laser or the like. Further, it can also be used in a method of forming a wiring pattern on a polymer film substrate and then planarizing the pattern forming surface. The diameter of the target wafer to be CMP by the polishing liquid is preferably 200 mm or more, and particularly preferably 300 mm or more.

<Interlayer insulating film> The interlayer insulating film preferably has a dielectric constant of 2.6 or less, and examples thereof include tantalum nitride or polycrystalline germanium. Further, 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) for preventing copper diffusion, and the copper is disposed between a conductor film (wiring) including copper or a copper alloy provided on the semiconductor substrate and the interlayer insulating film. As the material of the barrier metal film, a low-resistance metal material is preferable, and specifically, at least one selected from the group consisting of ruthenium, osmium compound, titanium, titanium compound, tungsten, tungsten compound, and ruthenium is preferable, and TiN is contained. TiW, Ta, TaN, W, WN or Ru is more preferred. Further, as the thickness of the barrier metal film, it is preferably about 20 to 30 nm.

The object to be polished used in the CMP method of the above embodiment can be produced, for example, by the following method. First, an interlayer insulating film such as tantalum nitride or polysilicon is laminated on a tantalum substrate. Then, a concave portion (substrate exposed portion) having a predetermined pattern is formed on the surface of the interlayer insulating film by a known method such as resist layer formation or etching, and is an interlayer insulating film including a convex portion and a concave portion. On the interlayer insulating film, a barrier layer covering the interlayer insulating film along the surface is formed by vapor deposition or chemical vapor deposition (CVD) of tungsten or a tungsten compound. In addition, a conductive material layer (hereinafter referred to as a conductor layer) which coats the barrier layer so as to fill the concave portion is formed by vapor deposition, plating, CVD, or the like on copper and/or a copper alloy, thereby obtaining An object to be polished having a laminated structure. The thickness of the interlayer insulating film, the barrier layer, and the copper layer is preferably 0.01 to 2.0 μm, 1 to 100 nm, and 0.01 to 2.5 μm, respectively.

[Polishing Apparatus] The polishing apparatus capable of performing the above 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 general CMP apparatus including a holder for holding a workpiece to be polished (for example, a semiconductor substrate or the like) and a polishing pad (a motor having a variable rotation speed or the like) can be used. Grinding platform. As a commercial item, Reflexion (made by Applied Materials, Inc.) can be used, for example.

<Grinding Pressure> In the CMP method of the above embodiment, polishing is preferably carried out at a pressure of 3000 to 25000 Pa, which is a pressure generated at a contact surface between the surface to be polished and the polishing pad, and is preferably polished at 6,500 to 14,000 Pa.

<Rotational Speed of Grinding Platform> In the CMP method of the above embodiment, polishing is preferably performed at a number of revolutions of the polishing table of 50 to 200 rpm, and polishing at 60 to 150 rpm is more preferable. Further, in order to relatively move the polishing body and the polishing pad, the holder can be rotated and/or oscillated, or the polishing table can be rotated by the planet, or the belt-shaped polishing pad can be linearly moved in one direction in the longitudinal direction. . In addition, the bracket may be in any state of being fixed, rotated or oscillated. These polishing methods can be appropriately selected by the surface to be polished and/or the polishing apparatus as long as the polishing body and the polishing pad are relatively moved.

<Method of Supplying Polishing Liquid> In the CMP method of the above embodiment, the polishing liquid is continuously supplied to the polishing pad on the polishing table by a pump or the like while polishing the surface to be polished. There is no limitation on the amount of supply, but the surface of the polishing pad is always coated with the polishing liquid preferably. In addition, the aspect of the polishing liquid is as described above. [Examples]

Hereinafter, the present invention will be described in detail based on examples. The materials, the amounts, the ratios, the processing contents, the processing steps, and the like shown in the following examples can be appropriately changed without departing from the gist of the invention. Therefore, the scope of the invention is not to be construed as limited by the embodiments shown below. In addition, unless otherwise indicated, “%” means “% by mass”.

[Example 1] Each component shown below was mixed to prepare a chemical mechanical polishing liquid. - Colloidal cerium oxide (average primary particle size: 35 nm, product name "PL3", manufactured by FUSO CHEMICAL CO., LTD., equivalent to abrasive grains.) 0.1% by mass ・Glycine (corresponding to organic acid and amino acid) 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 (equivalent to not A compound containing a benzotriazole skeleton and containing a 1,2,4-triazole skeleton.) 0.2% by mass ・Hydrogen peroxide (corresponding to an oxidizing agent) 1.0% by mass ・Ammonium nitrate (corresponding to a charge adjuster). ) 1000 mass ppm ・Methanol (corresponding to alcohol A) 500 ppm ・Residue of water (pure water)

[Examples 2 to 54 and Comparative Examples 1 to 5] Each of the components of Tables 1, 2, 3, and 4 was mixed in the same manner as in Example 1 to obtain each polishing liquid. In addition, each abbreviation symbol in Table 1 represents the following compounds and the like. In addition, the "content" in Table 1 represents the value under the mass standard. The pH of each treatment liquid was adjusted to the target pH by adding KOH/H ₂ SO ₄ .・PL3 (colloidal cerium oxide, product name "PL3", manufactured by FUSO CHEMICAL CO., LTD., average primary particle size: 35 nm, equivalent to abrasive grains.) ・Gly (corresponding to glycine, organic acid and amine group) Acid.) ・Ala (equivalent to alanine, organic acid and amino acid.) ・Asp (corresponding to aspartic acid, organic acid and amino acid.) ・NMG (equivalent to N-methylglycine, Organic acid and amino acid.) ・MaloA (equivalent to malonic acid, organic acid.) ・5-MBTA (equivalent to an azole compound having a 5-methylbenzotriazole or a benzotriazole skeleton.) BTA (equivalent to an azole compound having a benzotriazole or benzotriazole skeleton.) ・5,6-DMBTA (equivalent to an azole containing 5,6-dimethylbenzotriazole or benzotriazole skeleton) Compounds.) ・5-ABTA (corresponding to an azole compound containing a 5-aminobenzotriazole or a benzotriazole skeleton.) ・3-AT (equivalent to not containing 3-amino-1,2, 4-azole, azole triazole skeleton azole compound, and azole compound containing 1,2,4-triazole skeleton.) ・Triaz (equivalent to not containing 1,2,4-triazole, benzo Triazole bone An azole compound containing an azole compound having a 1,2,4-triazole skeleton.) ・3,5-DP (equivalent to a 3,5-dimethylpyrazole or benzotriazole skeleton) An azole compound.) ・Pyraz (corresponding to a pyrazole compound containing no pyrazole or benzotriazole skeleton and containing a pyrazole skeleton.) ・Imidaz (equivalent to an imidazole-free benzotriazole skeleton) An azole compound and an azole compound containing an imidazole skeleton.) ・5-ATZ (equivalent to an azole compound containing no 5-aminotetrazolium or benzotriazole skeleton.) ・Am-Ni (equivalent to Ammonium nitrate, charge adjuster.) ・Am-Bz (equivalent to ammonium benzoate, charge adjuster.) ・Am-Ci (equivalent to triammonium citrate, charge adjuster.) ・RE-610 (product name "Rhodafac RE-610", manufactured by Rhodia Inc., is equivalent to a surfactant.) ・MD-20 (product name "Surfynol MD-20", manufactured by Air Products and Chemicals, Inc., equivalent to a surfactant.) ・A43- NQ (product name "Takesurf-A43-NQ", manufactured by TAKEMOTO OIL & FAT CO., LTD., equivalent to anion table Surfactant.) ・S-465 (product name "Surfynol465", manufactured by Air Products and Chemicals, Inc., equivalent to a nonionic surfactant.) ・DBSH (equivalent to dodecylbenzenesulfonic acid, surfactant) .) ・MeOH (equivalent to methanol and alcohol A.) ・HEDP (equivalent to 1-hydroxyethylidene-1,1-diphosphonic acid, organic acid). DTPA (equivalent to diethylenetriamine pentaacetic acid, organic acid.) ・PHEAA: N-(2-hydroxyethyl) acrylamide polymer (weight average molecular weight 20000, equivalent to hydrophilic polymer.) PEIEO: a polyethylenimine having an oxyethylene chain having a repeating unit represented by the following, an HLB value of 18, and an n number: 20 (corresponding to a hydrophilic polymer.) [Chemical Formula 2]

[Evaluation of the temporal stability of the polishing liquid] The change in the state of aggregation of each of the prepared polishing liquids was measured using TURBISCAN (manufactured by SEISHIN ENTERPRISE Co., Ltd.: TURBISCAN 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 for 2 weeks in a thermostat at 40 ° C were measured, and the results were evaluated based on the following criteria. The results are shown in Tables 1 to 4. In addition, in practical applications, C or more is preferred. 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 exceeded 1% and 3% or less. C: The change in transmitted light intensity before and after storage exceeds 3% and 5% or less. D: The change in transmitted light intensity before and after storage exceeded 5%.

[Evaluation of Defect (Scratch) Performance] The Cu wafer of BLANKET was polished using each polishing liquid, and the polished Cu wafer was subjected to pure water washing, followed by drying. The dried Cu wafer was observed using an optical microscope, and the state of the surface to be polished of the Cu wafer was evaluated according to the following evaluation criteria. The results are shown in Tables 1 to 4. In addition, in practical applications, C or more is preferred. A: The total number of defects (number of defects/Cu wafer) is three or less B: the total number of defects is four or more and five or less C: the total number of defects is six or more and ten or less D: the total number of defects is 11 or more 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 of each of the prepared polishing liquids 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 dent] Under the following conditions, the polishing liquid was supplied while being supplied to the polishing pad, and the polishing rate and the dent were evaluated. - Grinding device: Reflexion (manufactured by Applied Materials, Inc.) ・Material to be polished (wafer): (1) Calculation of polishing rate; Copper: A blank of 300 mm in diameter of a Cu film having a thickness of 1.5 μm is formed on a tantalum substrate Wafer tungsten: a blank wafer of 300 mm in diameter with a W film having a thickness of 0.2 μm on a germanium substrate: a blank wafer having a thickness of 1.5 μm and a silicon nitride film having a thickness of 300 μm on a germanium substrate Polycrystalline germanium: a blank wafer having a diameter of 1.5 μm and a blank wafer having a diameter of 300 μm (2) for evaluation of pits on a germanium substrate; • copper: a copper wiring wafer (patterned wafer) having a diameter of 300 mm (mask pattern) 754CMP (ATDF)) Tungsten: Tungsten wiring wafer (patterned wafer) with a diameter of 300 mm (mask pattern 754CMP (ATDF)) ・ Tantalum nitride: 300 mm diameter tantalum nitride wiring wafer (pattern Wafer) (Mask Pattern 754CMP (ATDF)) ・Polysilicon: Polycrystalline silicon wiring wafer (patterned wafer) with a diameter of 300 mm (mask pattern 754CMP (ATDF)) ・Polish pad: IC1010 (Rodel Inc. Manufacturing) ・Brazil strip Grinding pressure (contact pressure of the surface to be polished): 1.5 psi (in addition, in this specification, psi means pound-force per square inch; pounds per square inch means 1 psi = 6794.76 Pa.) Liquid supply speed: 200ml/min Grinding platform speed: 110rpm Grinding head speed: 100rpm

(Evaluation method) Calculation of the polishing rate: The blank wafer of (1) was polished for 60 seconds, and the thickness of the metal film before and after the polishing was determined by converting the resistance value to 49 portions of the wafer surface at equal intervals. The average value of the value obtained by dividing the thickness of the metal film by the polishing time was defined as the polishing rate, and was evaluated based on the following criteria. The results are shown in Tables 1 to 4. Further, as the polishing rate, C or more is preferable 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.

・SiN nitride 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 the depression: For the patterned wafer of (2), in addition to the time when the copper of the non-wiring portion was completely polished, 25% of the polishing was performed for the time, using a contact type differential meter Dektak V320Si (Veeco Instruments, (manufactured by Inc.) The step of measuring the line and the space portion (line 10 μm, space 10 μm) was performed, and evaluation was performed based on the following criteria. The results are shown in Tables 1 to 4. In addition, in practical applications, it is preferable to evaluate G or more. A: The depression is 15 nm or less. B: The depression is more than 15 nm and 20 nm or less. C: The depression exceeds 20 nm and 25 nm or less. D: The depression is more than 25 nm and 30 nm or less. E: The depression is more than 30 nm and 35 nm or less. F: The depression exceeds 35 nm and 40 nm or less. G: The depression exceeds 40 nm and 45 nm or less. H: The depression exceeds 45 nm.

[Table 1]

[Table 2]

[table 3]

[Table 4]

[table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

[Table 13]

[Table 14]

[Table 15]

In (1), the composition of the polishing liquid of each of the examples and the comparative examples is described in each row in Table 1 (1) [1] to [3]. For example, the polishing liquid of the first embodiment contains 0.1% by mass of PL3 (relative to the total mass of the polishing liquid, the same applies hereinafter). As the abrasive grains, 1.5% by mass of Gly is contained as an organic acid, and each contains 0.001% by mass of 5-MBTA. 0.2% by mass of 3-AT as a preservative, containing 1.0% by mass of H ₂ O ₂ as an oxidizing agent, containing 1000 ppm by mass of Am-Ni as a charge adjuster, containing 500 ppm by mass of MeOH as the alcohol A, and the residual portion water. The pH is 7, and the mass ratio of the content of the alcohol A to each component is 0.50 with respect to the abrasive grains, 0.025 with respect to the organic acid system, 0.25 with respect to the preservative (total), and 0.050 with respect to the oxidant system. The adjusting agent is 0.50, the zeta potential is -45 mV, the stability is "A" with time, the Cu polishing rate is 375 nm/min, and the evaluation system is "B", the depressed system is 17 nm, and the evaluation system is "B", and the defect performance is "A". Regarding the above (Table 1), 2 and Tables 2 to 4 are also the same.

[Example 55] The polishing liquid of Example 55 was produced in the same manner as in Example 1 except that ethanol was used instead of methanol, and the same evaluation as described above was carried out, and the same evaluation as in Example 1 was carried out. result.

[Example 56] The polishing liquid of Example 56 was produced in the same manner as in Example 1 except that 1-propanol was used instead of methanol, and the results of the same evaluation as above were carried out. The same evaluation results.

[Example 57] The polishing liquid of Example 57 was produced in the same manner as in Example 1 except that isopropyl alcohol was used instead of methanol, and the results of the same evaluation as described above were the same as in Example 1. Evaluation results.

[Example 58] In Example 1, the abrasive grains were changed from PL3 to PL2 (colloidal cerium oxide, product name "PL2", manufactured by FUSO CHEMICAL CO., LTD., average primary particle diameter: 25 nm.), except Otherwise, the polishing liquid of Example 58 was produced in the same manner, and the results of the same evaluation as described above were the same as those of Example 1.

As is apparent from the results shown in Table 1, the polishing liquids of Examples 1 to 41 have a desired effect, and the polishing liquid contains polishing liquid for chemical mechanical polishing of abrasive grains, organic acids and alcohol A, and the alcohol A is selected from the group consisting of methanol. At least one of the group consisting of ethanol, 1-propanol and isopropyl alcohol, and the content of the alcohol A is 1.0 to 800 ppm by mass based on the total mass of the polishing liquid. On the other hand, the polishing liquids of Comparative Examples 1 to 4 did not have a desired effect. Further, the polishing liquids of Examples 1, 3, and 4 having a mass ratio of 0.001 to 0.05 with respect to the alcohol A of the organic acid have more excellent stability over time than the polishing liquid of Example 2, and The use of CMP further suppresses the generation of defects. Moreover, it has more excellent polishing speed and dent properties. The polishing liquid described above has more excellent polishing rate and dent property than the polishing liquid of Example 5. Further, the polishing liquids of Examples 1, 39, and 40 having a charge control agent content of 10 to 1000 ppm by mass further suppressed the occurrence of defects when used in CMP as compared with the polishing liquid of Example 38. On the other hand, the polishing liquid described above has more excellent stability with time than the polishing liquid of Example 37, and further suppresses generation of defects when used in CMP. Further, the polishing liquids of Examples 3, 4, 1, 5, 40 and 39 having a mass ratio of 0.1 to 50 with respect to the alcohol A of the charge control agent are more excellent than the polishing liquid of Example 41. It is stable over time and further suppresses the generation of defects when used in CMP. Moreover, it has a more excellent polishing speed. On the other hand, the above-mentioned polishing liquid has more excellent stability with time than the polishing liquid of Example 38, and further causes a defect when used in CMP. Further, the polishing liquids of Examples 11, 1 and 12 having a pH of 5.0 to 8.0 have more excellent stability over time than the polishing liquid of Example 10, and further suppress the occurrence of defects when used in CMP. . On the other hand, the above polishing liquid has more excellent depression properties than the polishing liquid of Example 13. Further, the polishing liquids of Examples 1 and 15 having an organic acid content of 1.0 to 20% by mass have an excellent polishing rate as compared with the polishing liquid of Example 14. On the other hand, the above polishing liquid has more excellent dent properties than the polishing liquid of Example 16.

no.

Claims (18)

A polishing liquid for polishing a chemical mechanical polishing liquid 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 isopropyl alcohol. The content of the alcohol A is 1.0 to 800 ppm by mass based on the total mass of the polishing liquid. The polishing liquid according to claim 1, wherein the mass ratio of the alcohol A to the organic acid is 0.001 to 0.05. The polishing liquid according to claim 1, further comprising a charge control agent containing at least one selected from the group consisting of inorganic acids, ammonium salts of organic acids, and ammonium salts of inorganic acids. The polishing liquid according to claim 3, wherein the content of the charge adjusting agent is from 10 to 1000 ppm by mass based on the total mass of the polishing liquid. The polishing liquid according to claim 3, wherein the mass ratio of the alcohol A to the charge adjusting agent is 0.1 to 50. The polishing liquid according to claim 1, wherein the organic acid is an amino acid. The slurry according to claim 6, wherein the amino acid is selected from the group consisting of glycine, alanine, arginine, isoleucine, leucine, lysine, phenylalanine, and the like. Winter amide, glutamine, lysine, histidine, valine, tryptophan, aspartic acid, glutamic acid, serine, threonine, tyrosine, cysteine At least one of the group consisting of methionine and N-methylglycine. The polishing liquid according to claim 6 or claim 7, wherein the polishing liquid contains two or more kinds of the aforementioned amino acids. The polishing liquid according to claim 1, wherein the slurry has a pH of 5.0 to 8.0. The slurry according to claim 1, which further contains an oxidizing agent. The polishing liquid according to claim 10, which contains two or more kinds of the above oxidizing agents. The polishing liquid according to claim 1, which further contains two or more kinds of azole compounds. The polishing liquid according to claim 12, wherein the two or more azole compounds contain a benzotriazole compound and an azole compound different from the benzotriazole compound. The polishing liquid according to claim 13, wherein the azole compound different from the benzotriazole compound is at least selected from the group consisting of a 1,2,4-triazole compound, a pyrazole compound, and an imidazole compound. 1 species. The polishing liquid according to claim 1, 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 1, wherein the abrasive granule is colloidal cerium oxide. A chemical mechanical polishing method comprising the following steps: supplying a polishing liquid according to any one of claims 1 to 16 to a polishing pad attached to a polishing table, and allowing the object to be polished The polishing surface is in contact with the polishing pad, and the polishing body and the polishing pad are relatively moved to polish the surface to be polished, thereby obtaining a polished object to be polished. The chemical mechanical polishing method according to claim 17, wherein the object to be polished contains at least one layer selected from the group consisting of copper, a copper alloy, tungsten, a tungsten alloy, tantalum nitride, and polycrystalline germanium.