JP2008118112A - Polishing solution for cmp and polishing method of substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing solution for CMP which can highly planarize a substrate without reducing a polishing speed at the formation of buried wiring of a metal film by CMP method, and can inhibit dishing and erosion, and to provide a polishing method of substrates. <P>SOLUTION: A polishing solution for CMP used to polish one or more selected from the group consisting of tungsten, tungsten nitride, tungsten alloy and other tungsten compounds comprises an abrasive grain, metal oxidant, a metal oxide resolvent, a metal anticorrosive, and water, wherein the metal anticorrosive comprises a compound having an imidazole skeleton. A process of polishing a substrate to form a conductor-buried wiring in a semiconductor integrated circuit comprises causing a relative movement between a polishing table and a substrate in a state that the substrate having a conductor deposition film and a barrier metal film beneath is pressed onto the polishing fabric, while supplying the polishing solution onto the polishing fabric on the polishing table, and continuously polishing the conductor deposition film and the barrier metal film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polishing liquid for chemical mechanical polishing (hereinafter referred to as CMP) and a method for polishing a substrate using the same.

  In recent years, new microfabrication techniques have been developed along with higher integration and higher performance of semiconductor integrated circuits (LSIs). The CMP method is one of them, and is a technique frequently used in planarization of an interlayer insulating film, formation of a metal plug, and formation of a buried wiring in an LSI manufacturing process, particularly in a multilayer wiring forming process (see, for example, Patent Document 1). ).

  The formation of the buried wiring using the CMP method will be described. A trench is formed in advance in the substrate, a barrier metal film such as titanium nitride is deposited on the entire surface of the interlayer insulating film such as an oxide film on the surface of the trench, and further, tungsten or the like is embedded in the trench on the entire barrier metal film. A wiring metal film is deposited.

  Next, an unnecessary wiring gold thin film other than the groove and the underlying barrier metal film are removed by CMP to form a buried wiring.

  This wiring forming method is called a damascene method. The damascene method is disclosed in Patent Document 2, for example.

  A general method of metal CMP is to apply a polishing pad on a circular polishing platen (platen), immerse the polishing pad surface with a metal polishing liquid, and press the surface on which the metal film of the substrate is formed. The polishing platen is rotated in a state where a predetermined pressure (polishing pressure or polishing load) is applied from the back surface, and the metal film on the convex portion is removed by mechanical friction between the polishing liquid and the convex portion of the metal film.

  The metal polishing liquid used in CMP is generally composed of an oxidizing agent and solid abrasive grains, and a metal oxide dissolving agent and a metal anticorrosive agent are further added as necessary.

  It is considered that the basic mechanism is to first oxidize the surface of the metal film by oxidation and scrape the oxidized layer with solid abrasive grains.

  Since the oxide layer on the metal surface of the concave portion does not touch the polishing pad so much and the effect of scraping off by the solid abrasive grains does not reach, the metal layer of the convex portion is removed with the progress of CMP, and the substrate surface is planarized (for example, (Refer nonpatent literature 1.).

  As a method for increasing the polishing rate by CMP, it is effective to add a metal oxide solubilizer. It is explained that if the metal oxide particles scraped by the solid abrasive grains are dissolved in the polishing liquid, the effect of scraping by the solid abrasive grains is increased.

  However, if the oxide layer on the surface of the metal film in the recess is dissolved (etched) and the metal film surface is exposed, the surface of the metal film is further oxidized by the oxidizing agent, and if this is repeated, the etching of the metal film in the recess proceeds. The flattening effect is impaired. In order to prevent this, a metal anticorrosive is further blended.

As a polishing liquid for polishing a tungsten film by CMP, for example, Patent Document 3 proposes a wafer polishing agent in which the average particle diameter of silica abrasive grains and the amount of NH ₄ OH are appropriately set and further an oxidizing agent is contained. Has been.

  When a buried wiring is formed by CMP using a conventional CMP polishing liquid, the following problems are likely to occur.

(1) The problem that the central portion of the surface of the embedded metal wiring is isotropically corroded and becomes a dish-like depression (hereinafter referred to as dishing) occurs.

(2) A problem that a decrease (hereinafter referred to as erosion) occurs in which the insulating film in the high-density wiring portion is reduced.

In addition, when adding a metal oxide solubilizer and a metal anticorrosive to the CMP polishing liquid as described above, it is not always easy to balance both agents.
U.S. Pat. No. 4,944,836 Japanese Patent Laid-Open No. 02-278822 Journal of Electrochemical Society, Vol. 138, No. 11 (published in 1991), pages 3460-3464 Japanese Patent Laid-Open No. 10-209092

  The present invention provides a polishing liquid for CMP and a method for polishing a substrate capable of suppressing dishing and erosion as well as high planarization without reducing the polishing speed when forming a buried wiring of a metal film such as tungsten by CMP. It is intended to provide.

  In order to achieve the above-mentioned problems, the present inventors have made various studies and found the following to complete the present invention.

  The present invention relates to (1) a polishing liquid used for polishing at least one selected from the group consisting of tungsten, tungsten nitride, tungsten alloys, and other tungsten compounds. The present invention relates to a polishing liquid containing an agent, a metal oxide solubilizer, a metal anticorrosive and water, wherein the metal anticorrosive contains a compound having an imidazole skeleton.

  In the present invention, (2) the compound having an imidazole skeleton is selected from the group consisting of 2-methylimidazole, 2-ethylimidazole, 2- (isopropyl) imidazole, 2-propylimidazole, 2-butylimidazole, 4-methylimidazole, 4- The present invention relates to the polishing slurry for CMP of (1), which is at least one compound selected from ethylimidazole, 2,4-dimethylimidazole, and 2-ethyl-4-methylimidazole.

  The present invention also relates to (3) the polishing slurry for CMP according to (1) or (2), further comprising a compound having a triazole skeleton as a metal anticorrosive.

  Further, in the present invention, (4) compounds having a triazole skeleton are 1,2,3-triazole, 1,2,4-triazole, 3-amino-1H-1,2,4-triazole, benzotriazole and 1 -The CMP polishing liquid according to (3), which is at least one compound selected from hydroxybenzotriazole.

  In the present invention, (5) the metal oxidizing agent is at least one compound selected from hydrogen peroxide, nitric acid, potassium periodate, hypochlorous acid and ozone water. 1) the polishing slurry for CMP.

  In the present invention, any one of the above (1) to (5), wherein (6) the metal oxide solubilizer is at least one compound selected from organic acids, organic acid esters, ammonium salts of organic acids, and sulfuric acid. The present invention relates to a CMP polishing liquid.

  The present invention also provides (7) a method for polishing a substrate for forming a conductor-embedded wiring in a semiconductor integrated circuit, wherein the CMP according to any one of (1) to (6) above is performed on a polishing cloth of a polishing surface plate. While supplying the polishing liquid, while the substrate having the conductor deposited film and the barrier metal film underneath is pressed against the polishing cloth, the polishing platen and the substrate are moved relative to each other to move the conductor deposited film and its lower layer. The present invention relates to a substrate polishing method for continuously polishing the barrier metal film.

  According to the present invention, since the polishing rate of tungsten metal is high and the etching rate is low, a polishing slurry for CMP with low dishing and erosion can be obtained.

  This CMP polishing liquid is excellent in miniaturization, thinning, dimensional accuracy, and electrical characteristics, and is suitable for polishing highly reliable semiconductor devices and equipment.

  Further, according to the present invention, in addition to the effects of the above-described invention, since any of the tungsten deposited film and the barrier metal film thereunder can be polished, no separate CMP polishing liquid for polishing the barrier metal film is required. Since the tungsten deposited film and the underlying barrier metal film can be polished continuously, it is possible to provide a polishing method for obtaining a semiconductor device having further excellent productivity.

  Hereinafter, the best mode for carrying out the invention will be described in detail.

  In the present invention, the conductor to be scraped off is a metal film made of a deposited film having at least one metal layer of tungsten, tungsten nitride, tungsten alloy, and other tungsten compounds. Of these tungsten compounds, tungsten, tungsten nitride, and tungsten alloys are particularly preferable in terms of the balance between the polishing rate and the etching rate.

  In the present invention, the barrier metal film under the conductor to be scraped is at least one metal of titanium, titanium nitride, titanium alloy, other titanium compounds, tantalum, tantalum nitride, tantalum alloy, or other tantalum compounds. The metal film is preferably a laminated film having a film. Of these, titanium and titanium nitride are particularly preferable in terms of adhesion to tungsten, tungsten nitride, and tungsten alloys.

  In the present invention, as the abrasive grains used in the polishing liquid, any of inorganic abrasive grains such as silica, alumina, ceria, titania, zirconia, germania and silicon carbide, and organic abrasive grains such as polystyrene, polyacryl and polyvinyl chloride can be used. However, colloidal silica having an average particle size of 100 nm or less is preferable in that the dispersion stability in the polishing liquid is good and the number of polishing scratches (scratches) generated by CMP is small. Colloidal silica can be produced by hydrolysis of silicon alkoxide or ion exchange of sodium silicate.

  Further, the concentration of the abrasive grains in the polishing liquid is preferably 0.01% by mass to 10% by mass, and more preferably 0.05% by mass to 5% by mass. If it is less than 0.01% by mass, there is no difference from the polishing rate in the case of not containing abrasive grains.

In the present invention, the metal oxidizing agent used in the polishing liquid includes hydrogen peroxide (H ₂ O ₂ ), nitric acid, potassium periodate, hypochlorous acid, ozone water, etc. Among them, hydrogen peroxide is preferable. In the case where the substrate to be applied is a silicon substrate including an integrated circuit element, an oxidizing agent that does not contain a nonvolatile component is preferable in order to avoid contamination with alkali metals, alkaline earth metals, halides, and the like. Also, ozone water requires caution because the composition changes with time. In the case where the substrate is a glass substrate that does not include a semiconductor element, an oxidizing agent that includes a nonvolatile component may be used.

  The concentration of the metal oxidizing agent in the polishing liquid in the present invention is preferably 0.1% by mass to 50% by mass, more preferably 0.2% by mass to 40% by mass, and 0.3% by mass. It is especially preferable to set it as% -30 mass%. If the concentration is less than 0.1% by mass, metal oxidation is insufficient and the CMP rate is low, and if it exceeds 50% by mass, the polished surface tends to be rough.

  As the metal oxide solubilizer used in the present invention, the metal oxide solubilizer is preferably at least one compound selected from organic acids, organic acid esters, ammonium salts of organic acids and sulfuric acid. There is no particular limitation as long as it is water-soluble, but formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methyl Pentanoic acid, n-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 And organic acids such as pimelic acid, maleic acid, phthalic acid, 3-nitrophthalic acid, malic acid, tartaric acid and citric acid, organic acid esters thereof, and ammonium salts of these organic acids.

  Examples of inorganic acids that can be used in addition to sulfuric acid include inorganic acids such as hydrochloric acid and nitric acid, and ammonium salts of these inorganic acids such as ammonium persulfate, ammonium nitrate, and ammonium chloride, and chromic acid.

  Among these, formic acid, malonic acid, phthalic acid, 3-nitrophthalic acid, malic acid, tartaric acid, and citric acid are tungsten and nitrided in that the etching rate can be effectively suppressed while maintaining a practical CMP rate. It is suitable for a deposited film including at least one metal layer selected from tungsten, a tungsten alloy, and an oxide of tungsten or tungsten alloy. These may be used alone or in combination of two or more.

  In the present invention, the concentration of the metal oxide solubilizer in the polishing liquid is preferably 0.001% by mass to 10% by mass, more preferably 0.01% by mass to 8% by mass, and 0.02%. It is especially preferable to set it as mass%-5 mass%. When this amount is less than 0.001% by mass, polishing residue tends to increase, and when it exceeds 10% by mass, it tends to be difficult to suppress etching.

  The metal anticorrosive used in the present invention is not particularly limited as long as a compound having an imidazole skeleton is included. Examples of the compound having an imidazole skeleton include 2-methylimidazole, 2-ethylimidazole, 2- (isopropyl) imidazole, Examples include 2-propylimidazole, 2-butylimidazole, 4-methylimidazole, 4-ethylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, and 2-aminoimidazole. . These can be used individually by 1 type or in mixture of 2 or more types. Among them, 2-methylimidazole, 2-ethylimidazole, 2- (isopropyl) imidazole, 2-propylimidazole, 2-butylimidazole, 4-methylimidazole, 4-ethylimidazole, 2,4-dimethylimidazole, 2-ethyl At least one compound selected from -4-methylimidazole is preferable in terms of the balance between the polishing rate and the etching rate.

  As the metal anticorrosive used in the present invention, a compound having a triazole skeleton can be further used together with a compound having an imidazole skeleton. Examples of the compound having a triazole skeleton include 1,2,3-triazole, 1,2,4-triazole, 3-amino-1H-1,2,4-triazole, benzotriazole, 1-hydroxybenzotriazole, 1-hydroxybenzotriazole, Dihydroxypropylbenzotriazole, 2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole, 4-carboxyl (-1H-) benzotriazole, 4-carboxyl (-1H-) benzotriazole methyl ester, 4-carboxyl (- 1H-) benzotriazole butyl ester, 4-carboxyl (-1H-) benzotriazole octyl ester, 5-hexylbenzotriazole, [1,2,3-benzotriazolyl-1-methyl] [1,2,4- Triazolyl-1- Chill] [2-ethylhexyl] amine, tolyltriazole, naphthotriazole, bis [(1-benzotriazolyl) methyl] phosphonic acid. These can be used individually by 1 type or in mixture of 2 or more types. In particular, 1,2,3-triazole, 1,2,4-triazole, 3-amino-1H-1,2,4-triazole, benzotriazole and 1-hydroxybenzotriazole are preferable in terms of solubility in water. .

  The concentration of the metal anticorrosive agent (including those that can be used in combination with a compound having an imidazole skeleton) in the polishing liquid of the present invention is preferably 0.001% by mass to 10% by mass, and 0.01% by mass to 8%. It is more preferable to set it as mass%, and it is especially preferable to set it as 0.02 mass%-5 mass%.

  When the amount is less than 0.001% by mass, it is difficult to suppress etching, and when it exceeds 10% by mass, the polishing rate tends to be low. In particular, when only a compound having an imidazole skeleton is used as the metal anticorrosive, the content is preferably 0.03% by mass to 5% by mass.

  The CMP polishing liquid according to the present invention may contain a water-soluble polymer. The water-soluble polymer is not particularly limited. For example, polysaccharides such as alginic acid, pectic acid, carboxymethylcellulose, agar, curdlan, and pullulan; polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid, polymethacrylic acid. Acid ammonium salt, polymethacrylic acid sodium salt, polyamic acid, polymaleic acid, polyitaconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, ammonium polyacrylate, polyacrylic Polycarboxylic acid such as sodium acid salt, polyamic acid, ammonium polyamic acid salt, sodium polyamic acid salt and polyglyoxylic acid, polycarboxylic acid ester and salts thereof; polyvinyl alcohol, polyvinyl Pyrrolidone, and vinyl-based polymers polyacrolein, and the like.

  However, when the substrate to be applied is a silicon substrate for a semiconductor integrated circuit or the like, contamination with an alkali metal, an alkaline earth metal, a halide or the like is not desirable, so an acid or an ammonium salt thereof is desirable. This is not the case when the substrate is a glass substrate or the like.

  Of these, pectic acid, agar, polymalic acid, polymethacrylic acid, polyacrylic acid, polyacrylamide, polyvinyl alcohol and polyvinylpyrrolidone, esters thereof and ammonium salts thereof are preferable.

  The weight average molecular weight of the water-soluble polymer is preferably 500 or more, more preferably 1500 or more, and particularly preferably 5000 or more. The upper limit of the weight average molecular weight is not particularly specified, but is preferably 5 million or less from the viewpoint of solubility. When the weight average molecular weight is less than 500, a high polishing rate tends not to be exhibited. The weight average molecular weight can be measured by gel permeation chromatography using a standard polystyrene calibration curve.

  These water-soluble polymers have the effect of forming a protective film for protecting the metal surface, and improve the planarization characteristics such as the suppression of dishing together with the action of the contained metal anticorrosive.

  In addition to the materials described above, the polishing slurry for CMP of the present invention contains a surfactant, a dye such as Victoria Pure Blue, a colorant such as a pigment such as phthalocyanine green, a solvent such as a glycol monoether or alcohol. You may make it contain.

  In the method for polishing a substrate of the present invention, in order to form a conductor embedded wiring in a semiconductor integrated circuit, while supplying the CMP polishing liquid onto a polishing cloth of a polishing surface plate, a conductor deposited film and a barrier thereunder This is a polishing method in which the deposited film of the conductor and the underlying barrier metal film are continuously polished by relatively moving the polishing surface plate and the substrate while pressing the substrate having the metal film against the polishing cloth.

  Examples of the conductor to be polished by applying the polishing liquid of the present invention include tungsten, tungsten nitride, tungsten alloy, and tungsten compounds such as oxide of tungsten and oxide of tungsten alloy. Known sputtering methods and plating methods The method is applied to polishing a metal film formed by the above method.

  The barrier metal film applied to the present invention includes at least one barrier metal selected from titanium, titanium nitride, titanium alloys, other titanium compounds, tantalum, tantalum nitride, tantalum alloys, and other tantalum compounds. It is preferable that it is a laminated film containing.

  As a polishing apparatus, a general polishing apparatus having a holder for holding a substrate and a polishing surface plate to which a polishing cloth (pad) can be attached and a motor or the like capable of changing the number of rotations can be used. .

  As an abrasive cloth, a general nonwoven fabric, a polyurethane foam, a porous fluororesin, etc. can be used, and there is no restriction | limiting in particular.

  The polishing conditions are not limited, but the rotation speed of the surface plate is preferably a low rotation of 200 rpm or less so that the substrate does not jump out.

  The pressing pressure (polishing load) of the substrate having the film to be polished onto the polishing cloth is preferably 1 to 100 kPa. In order to satisfy the uniformity of the wafer surface in the CMP rate and the flatness of the pattern, the pressure is 5 to 50 kPa. It is more preferable that

  During polishing, a polishing solution for metal is continuously supplied to the polishing cloth with a pump or the like.

  Although there is no restriction | limiting in this supply amount, it is preferable that the surface of polishing cloth is always covered with polishing liquid.

  The substrate after polishing is preferably washed in running water and then dried after removing water droplets adhering to the substrate using spin drying or the like.

  The polishing method of the present invention includes an interlayer insulating film having a surface having recesses and protrusions, a barrier metal layer that covers the interlayer insulating film along the surface, and a conductor layer that fills the recess and covers the barrier metal layer It is preferably used for polishing a substrate having The polishing step in this case includes a first polishing step for polishing the conductor layer to expose the barrier metal layer of the convex portion, and polishing at least the barrier metal layer and the conductor layer of the concave portion to form the convex interlayer insulating film. A second polishing step to be exposed. If the polishing liquid of this invention is used, a 1st grinding | polishing process and a 2nd grinding | polishing process can be grind | polished continuously.

  Examples of the interlayer insulating film include a silicon-based film and an organic polymer film. Silicon-based coatings include silicon dioxide, fluorosilicate glass, organosilicate glass obtained using trimethylsilane and dimethoxydimethylsilane as starting materials, silicon-based coatings such as silicon oxynitride and silsesquioxane hydride, silicon carbide and A silicon nitride is mentioned. Examples of the organic polymer film include a wholly aromatic low dielectric constant interlayer insulating film. In particular, organosilicate glass is preferable. These films are formed by a CVD method, a spin coating method, a dip coating method, or a spray method.

  In the first polishing step, by polishing the conductive film on the surface of the above structure, a desired conductive pattern in which the convex barrier metal layer on the substrate is exposed on the surface and the conductive film is left in the concave is obtained. It is done.

  Subsequently, in the second polishing step, at least the exposed barrier metal layer and the conductor film in the recess are polished. Desired pattern in which all of the interlayer insulating film under the barrier metal layer in the convex part is exposed, the conductor film to be a metal wiring layer is left in the concave part, and the cross section of the barrier metal layer is exposed at the boundary between the convex part and the concave part Polishing is finished when In order to ensure better flatness at the end of polishing, over polishing (for example, if the time until a desired pattern is obtained in the second polishing step is 100 seconds, in addition to this 100 second polishing) Polishing for an additional 50 seconds may be referred to as over-polishing 50%), and may be polished to a depth including a portion of the convex interlayer insulating film.

  In the polishing under the same conditions, it is preferable that the polishing rate ratio of tungsten / barrier metal layer / interlayer insulating film is polished at 1/1 to 4/2 to 5.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not restrict | limited by these Examples.

(Polishing liquid preparation method)
The polishing liquid for CMP used by Examples 1-6 and Comparative Examples 1-2 by the compounding ratio shown in Table 1 was produced.

(Polishing conditions)
Base 1: Silicon substrate on which a 800 nm thick tungsten film is formed Base 2: Silicon substrate on which a 200 nm thick titanium nitride film is formed Base 3: Wiring groove depth in silicon dioxide 0.5 μm, width 0.5-100 μm Next, a titanium nitride film having a heat thickness of 30 nm is formed as a barrier metal by a known sputtering method, and a tungsten film as a wiring metal is similarly formed by a sputtering method to form a 1.0 μm thickness by a known heat treatment. Embedded silicon substrate Polishing pad: Polyurethane foam resin (Model number IC1010 manufactured by Rodel)
Polishing pressure: 140 gf / cm ² (13.7 kPa), relative speed between substrate and polishing platen: 100 m / min
(Abrasive product evaluation items)
Polishing rate: The difference in film thickness before and after polishing of the tungsten film of the substrate 1 and the titanium nitride film of the substrate 2 was calculated from the electric resistance value.

Etching rate: The difference in tungsten film thickness of the substrate 1 before and after immersion in a stirred CMP polishing liquid (room temperature, 25 ° C., stirring 100 min ⁻¹ ) was calculated from the electrical resistance value.

  Dishing amount: Using the substrate 3, the first polishing step and the second polishing step were continuously polished on the entire surface of the substrate until the silicon dioxide of the convex portions of the pattern was exposed.

  Next, the film reduction amount of the wiring metal part with respect to the insulating film part was obtained from the surface shape of the stripe pattern part in which the wiring metal part width of 100 μm and the insulating film part width of 100 μm were alternately arranged with a stylus step meter.

  Erosion amount: Surface shape after polishing of a stripe pattern portion having a total width of 2.5 mm in which a wiring metal portion width of 4.5 μm and an insulating film portion width of 0.5 μm are alternately formed on the dishing amount evaluation base 3 Was measured with a stylus type step meter, and the amount of film reduction of the insulating film portion near the center of the pattern with respect to the insulating film field portion around the stripe pattern was determined.

Table 2 shows polishing rates, etching rates, dishing amounts, and erosion amounts by Examples 1 to 6 and Comparative Examples 1 and 2 by CMP.

  As shown in Table 2, it is clear that both Comparative Examples 1 and 2 have large dishing and erosion due to the high etching rate of the tungsten film.

  On the other hand, in Examples 1-6, since the etching speed | rate of a tungsten film is small, it is clear that dishing and erosion are small compared with a comparative example.

Claims (7)

  A polishing liquid used for polishing at least one selected from the group consisting of tungsten, tungsten nitride, tungsten alloys, and other tungsten compounds, comprising abrasive grains, a metal oxidizer, and a metal oxide solubilizer Polishing liquid for CMP which is a polishing liquid containing a metal anticorrosive and water, and the metal anticorrosive contains a compound having an imidazole skeleton.   Compounds having an imidazole skeleton are 2-methylimidazole, 2-ethylimidazole, 2- (isopropyl) imidazole, 2-propylimidazole, 2-butylimidazole, 4-methylimidazole, 4-ethylimidazole, and 2,4-dimethylimidazole. 2. The polishing slurry for CMP according to claim 1, which is at least one compound selected from 2-ethyl-4-methylimidazole.   The polishing slurry for CMP according to claim 1 or 2, further comprising a compound having a triazole skeleton as a metal anticorrosive.   The compound having a triazole skeleton is at least one selected from 1,2,3-triazole, 1,2,4-triazole, 3-amino-1H-1,2,4-triazole, benzotriazole and 1-hydroxybenzotriazole. The polishing slurry for CMP according to claim 3, which is a seed compound.   The polishing slurry for CMP according to claim 1, wherein the metal oxidizing agent is at least one compound selected from hydrogen peroxide, nitric acid, potassium periodate, hypochlorous acid, and ozone water.   The polishing slurry for CMP according to any one of claims 1 to 5, wherein the metal oxide solubilizer is at least one compound selected from organic acids, organic acid esters, ammonium salts of organic acids, and sulfuric acid.   A method for polishing a substrate for forming a conductor-embedded wiring in a semiconductor integrated circuit, wherein a conductor deposited film is supplied while supplying the polishing slurry for CMP according to claim 1 onto a polishing cloth of a polishing surface plate. With the substrate having the barrier metal film underneath and the substrate pressed against the polishing cloth, the deposited film of the conductor and the barrier metal film under the conductor are polished continuously by moving the polishing surface plate and the substrate relatively. A method for polishing a substrate, which is characterized.