JP2007227808A - Chemical mechanical polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemical mechanical polishing method for polishing a workpiece having a barrier metal film and a conductor film, which has improved efficiency of polishing processing by continuously polishing the conductor film and the barrier metal film using the same polishing table, in a step of manufacturing a semiconductor device. <P>SOLUTION: The chemical mechanical polishing method is used to polish the workpiece having the barrier metal film and the conductor film provided on the barrier metal film. In this method, a first polishing process in which a polishing solution A is used to polish the conductor film, and a second polishing process in which a polishing solution B is used to polish the barrier metal film are continuously executed on the same polishing table having a polishing pad arranged thereon, and the polishing solutions A and B each contain (1) particles obtained by a dynamic optical dispersion method and having an average within a range of 60-150 nm, (2) particles obtained by a dynamic optical dispersion method and having an average within a range of 10-50 nm and (3) an oxidizing agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chemical mechanical polishing method. More particularly, the present invention relates to a chemical mechanical polishing method capable of efficient processing during polishing processing in a semiconductor device manufacturing process.

Copper is a low resistance material in the formation of semiconductor integrated circuits where miniaturization and high density are accelerated, and in recent years, it has attracted much attention as a very useful electrical connection material.
Currently, formation of wiring using copper and an alloy containing copper as a main component is generally performed as follows. That is, after forming recesses such as grooves and connection holes in the insulating film, forming a barrier metal film, a copper film is formed by plating so as to fill the recesses, and then chemical mechanical polishing (hereinafter referred to as chemical mechanical polishing) Polishing until the surface of the insulating film other than the recesses is completely exposed, thereby flattening the surface and forming electrical connection portions such as embedded copper wiring, via plugs, contact plugs, etc. with copper embedded in the recesses is doing.

  In the method of forming the buried copper wiring, a lower wiring layer made of an insulating film having a lower wiring is formed on a silicon substrate, and a silicon nitride film is formed thereon by chemical vapor deposition (CVD). An insulating film is formed in this order by a phase growth (CVD) method or a coating method. Next, a recess having a wiring pattern shape and reaching the silicon nitride film is formed in the insulating film. Subsequently, a barrier metal film is formed by a sputtering method. Thereafter, a copper film (conductor film) is formed on the entire surface by electrolytic plating so that the recesses are embedded thereon. Thereafter, the copper film is polished by chemical mechanical polishing (CMP) to planarize the substrate surface. Subsequently, polishing by CMP is continued until the barrier metal film on the silicon nitride film is completely removed.

A general method of CMP is to rotate a circular polishing platen (platen) to which a polishing pad is attached while dropping and holding a polishing liquid on the surface of the polishing pad, and further to a substrate (wafer) on the surface of the polishing pad. The surface of the substrate is pressed, the substrate is rotated with a predetermined pressure (polishing pressure) applied from the back surface, and the surface of the substrate is flattened by mechanical friction generated by the relative movement between the polishing platen and the substrate. is there.
A polishing liquid used for CMP generally contains abrasive grains (for example, alumina and silica) and an oxidizing agent (for example, hydrogen peroxide and persulfuric acid). It is thought that the basic mechanism is polishing by oxidizing the metal surface with an oxidizing agent and removing the oxide film with abrasive grains (see, for example, Non-Patent Document 1).

Further, in order to remove the polishing liquid remaining on the surface of the substrate, which is the surface to be polished, after polishing, a step of washing by dropping / supplying ultrapure water continuously after the polishing liquid is required after polishing ( Called water polishing).
Further, during polishing, solid abrasive grains and polishing scraps (polishing products) are deposited on the polishing pad, reducing the holding power of the polishing liquid on the polishing pad surface, resulting in a decrease in polishing efficiency. In addition, this deposit also causes scratches on the surface to be polished, which is a major problem in polishing.

Therefore, the accumulated solid abrasive grains and polishing debris are removed by dressing or conditioning (hereinafter referred to as conditioning) before performing the next polishing.
In general, a grinding wheel called a pad conditioner is used for conditioning the polishing pad (see, for example, Patent Document 1). In this pad conditioner, an abrasive layer in which diamond abrasive grains are fixed with a metallic binder phase such as nickel is formed on the surface of a substantially disk-shaped substrate made of iron or stainless steel. The abrasive layer is formed so as to extend radially from the vicinity of the center of the surface of the substrate toward the outer peripheral side. Then, by pressing the surface of the substrate against the surface of the polishing pad being rotated around the axis with a constant load, the substrate performs a rotational motion along with the rotational motion of the polishing pad, The surface of the polishing pad is cut with the abrasive layer to remove deposits on the surface.

As described above, water polishing and conditioning of the polishing pad are necessary after polishing, and it is desirable to omit these steps when considering the efficiency of the polishing process.
Further, in the conventional main method, the CMP is divided into two stages, that is, Cu-CMP for polishing the conductive film and barrier CMP for polishing the barrier metal film. Usually, different polishing liquids and polishing pads (polishing rooms) are used. ) And polishing is performed on a different polishing platen.
The main reason is that the optimum polishing pad type and pad conditioning conditions differ depending on the polishing liquid. The term “optimal” as used herein refers to a state in which polishing characteristics such as polishing speed, flattening characteristics, and the presence or absence of scratches are comprehensively adjusted.

Note that the polishing liquid used in the Cu-CMP is sometimes expressed as a polishing liquid for a conductor film, which is a polishing liquid used mainly for polishing a copper film (conductor film) to flatten the substrate surface. It does not indicate that the barrier film cannot be polished.
Similarly, although the polishing liquid used in the barrier CMP is referred to as a barrier polishing liquid, it is a polishing liquid that is mainly used for completely removing the barrier metal film on the silicon oxide film and cannot polish the conductor film. It does not refer to liquid.
As described above, performing Cu-CMP and barrier CMP separately requires extra transport time between polishing pads (chambers), cleaning time of each chamber, conditioning time, and the like, which increases the efficiency of CMP processing. Unfavorable above.
Japanese Patent Laid-Open No. 10-193269 Journal of Electrochemical Society (1991, Vol. 138, No. 11, pages 3460-3464)

This invention is made | formed in view of the said problem, and makes it a subject to achieve the following objectives.
That is, the present invention relates to a chemical mechanical polishing method for polishing an object to be polished having a barrier metal film and a conductor film provided on the barrier metal film in a semiconductor device manufacturing process, An object of the present invention is to provide a chemical mechanical polishing method in which the barrier metal film and the barrier metal film can be continuously polished on the same polishing surface plate, and the efficiency of the polishing process is improved.

As a result of intensive studies, the present inventor has found that the above problems can be solved by using polishing liquids containing abrasive particles having different particle diameters, and has achieved the object.
That is, the present invention is as follows.

<1> A chemical mechanical polishing method for polishing an object to be polished having a barrier metal film and a conductor film provided on the barrier metal film,
The first polishing step of polishing the conductor film using the polishing liquid A and the second polishing step of polishing the barrier metal film using the polishing liquid B are the same polishing constant in which the polishing pad is disposed. A chemical mechanical polishing method which is carried out continuously on a board, and wherein the polishing liquid A and the polishing liquid B contain the following components (1) to (3).
Component (1): Particle component having an average particle size in the range of 60 to 150 nm determined by the dynamic light scattering method (2): Particle component having an average particle size in the range of 10 to 50 nm determined by the dynamic light scattering method ( 3): Oxidizing agent

Although the operation of the present invention is not clear, it is estimated as follows.
In the present invention, clogging of pad vacancies is suppressed by using particles having different particle sizes as abrasive particles, and a decrease in polishing rate due to this is prevented. In addition, the occurrence of scratches on the polished surface can be suppressed by suppressing the clogging. As a result, even if the conductor film and the barrier metal film are continuously polished on the same polishing platen, it is possible to perform high-quality polishing with few scratches without increasing the processing time. Become.

<2> The chemical mechanical polishing method according to <1>, wherein the polishing pads used in the first polishing step and the second polishing step are the same.
<3> The chemical mechanical polishing method according to <1> or <2>, wherein the polishing liquid A and the polishing liquid B have a pH of 2 to 7.
<4> The total content of the component (1) and the component (2) is within the following range with respect to the mass of the polishing liquid A or the polishing liquid B, <1> to <3 > The chemical mechanical polishing method according to any one of the above.
Polishing liquid A: 0.01-2.0 mass% with respect to the mass of the polishing liquid A
Polishing liquid B: 1.0-10 mass% with respect to the mass of the polishing liquid B
<5> The component (3) is hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, perchlorate, <1> to <4, which is at least one selected from the group consisting of sulfate, dichromate, permanganate, ozone water, silver (II) salt, and iron (III) salt > The chemical mechanical polishing method according to any one of the above.
<6> The chemical mechanical polishing method according to <5>, wherein the component (3) is hydrogen peroxide.

According to the present invention, there is provided a chemical mechanical polishing method for polishing an object to be polished having a barrier metal film and a conductor film provided on the barrier metal film in a semiconductor device manufacturing process, the conductor film And the barrier metal film can be continuously polished with the same polishing platen, and a chemical mechanical polishing method with improved polishing efficiency can be provided.
According to this chemical mechanical polishing method, it is possible to obtain a polished surface having a good surface shape and a suppressed residue.

Hereinafter, specific embodiments of the present invention will be described.
The chemical mechanical polishing method of the present invention is a chemical mechanical polishing method for polishing an object to be polished, which has a barrier metal film and a conductor film provided on the barrier metal film. The first polishing step for polishing the conductive film using the second polishing step for polishing the barrier metal film using the polishing liquid B is continuously performed on the same polishing platen on which the polishing pad is disposed. The chemical mechanical polishing method is characterized in that the polishing liquid A and the polishing liquid B contain the following components (1) to (3).
Component (1): Particle component having an average particle size in the range of 60 to 150 nm determined by the dynamic light scattering method (2): Particle component having an average particle size in the range of 10 to 50 nm determined by the dynamic light scattering method ( 3): Oxidizing agent

  Here, in the present invention, the polishing pad arranges “a first polishing step for polishing the conductor film using the polishing liquid A and a second polishing step for polishing the barrier metal film using the polishing liquid B”. "Continuously performed on the same polishing surface plate" means that after polishing the conductor film using the polishing liquid A on the polishing surface plate, the transfer to another polishing surface plate, conditioning, etc. It means that the barrier metal film is polished using the polishing liquid B on the same polishing surface plate as that used for polishing the conductor film without performing the treatment. Moreover, it is preferable from a viewpoint of an efficiency improvement that the polishing pad used for both processes is also the same.

Hereinafter, the components contained in the polishing liquid A and the polishing liquid B used in the chemical mechanical polishing method of the present invention will be described below.
Hereinafter, the polishing liquid A and the polishing liquid B may be collectively referred to as “polishing liquid”.
The polishing liquid A and the polishing liquid B in the present invention are required to contain the components (1) to (3). By adjusting the amount of each of these components (1) to (3), the polishing liquid A can have a composition suitable for polishing the conductor film, and the polishing liquid B polishes the barrier metal film. It can be set as a suitable composition to do. As a result, even if the first polishing step and the second polishing step are performed on the same polishing surface plate, the conductor film and the barrier metal film of the object to be polished can be polished.
In addition, the content (addition amount) of various components with respect to the polishing liquid shown below is “the polishing liquid used for polishing (that is, the diluted polishing liquid when diluted with water or an aqueous solution)” It is content (addition amount) with respect to.
The components (1) to (3) will be described in detail.

[Polishing liquid]
Hereinafter, each component which comprises the polishing liquid in this invention is demonstrated first.
(Component (1): Particles having an average particle diameter of 60 to 150 nm determined by the dynamic light scattering method, and Component (2): An average particle diameter determined by the dynamic light scattering method of 10 to 50 nm. Particles)
The polishing liquid of the present invention comprises a component (1): particles having an average particle size in the range of 60 to 150 nm determined by the dynamic light scattering method, and a component (2): average particle size determined by the dynamic light scattering method. In the range of 10 to 50 nm as abrasive particles.
In the present invention, the average particle diameter in each particle of component (1) and component (2) refers to the volume average particle diameter.

The average particle size of the component (1) particles in the present invention is 60 to 150 nm, more preferably 65 to 100 nm. That is, particles of 60 nm or more are preferred for the purpose of achieving a sufficient polishing speed. In addition, the particle size is preferably 150 nm or less from the viewpoint of planarization characteristics.
The average particle diameter of the component (2) particles in the present invention is 10 to 50 nm, and more preferably 15 to 40 nm. That is, particles of 10 nm or more are preferable for the purpose of achieving a sufficient polishing speed with less clogging. Further, the particle diameter is preferably 50 nm or less from the viewpoint of planarization characteristics.

The average particle diameter (volume average particle diameter) of each particle is determined by a dynamic light scattering method. Specifically, it can measure using the particle size distribution measuring apparatus (Horiba Ltd. make, LB-500) which employ | adopted the dynamic light-scattering method.
In addition, although the average particle diameter in this invention can be measured by the said method respectively about a component (1) and a component (2), when both are mixed in polishing liquid, a dynamic light scattering method is employ | adopted. Each of the volume average particle diameters can be confirmed by a particle size distribution measuring apparatus (manufactured by Horiba, Ltd., LB-500).

  Specific examples of the component (1) and the component (2) in the present invention include fumed silica, colloidal silica, fumed alumina, and fumed titania, and preferably colloidal silica.

The colloidal silica suitable for the present invention can be produced, for example, by the following method.
As a wet manufacturing method of metal oxide particles, colloidal particles are obtained by, for example, a method of hydrolyzing metal alkoxide as a starting material. Specifically, orthosilicic acid is added to an alkaline aqueous solution mixed with alcohol. Colloidal silica can be produced by dropping methyl at a certain rate to cause hydrolysis and undergoing grain growth and quenching to stop grain growth. In addition, colloidal particles are made using alkoxides such as aluminum and titanium. In this case, the rate of hydrolysis is generally faster than when silicon alkoxide is used, which is convenient when producing ultrafine particles.

  Further, as a dry manufacturing method of metal oxide, fumed particles can be obtained by a reaction in which a metal chloride is introduced into an oxyhydrogen flame and the dechlorinated metal is oxidized. Furthermore, the metal or alloy desired to be contained in the target substance is pulverized into powder, and this is put into an oxygen flame containing a combustion-supporting gas, causing a continuous reaction by the oxidation heat of the metal, and fine A method for obtaining oxide particles has been put into practical use. Particles produced by these combustion methods are amorphized because they are rapidly cooled after being exposed to high heat, and the solid density is generally low because there are fewer impurities such as hydroxyl groups inside than wet particles. It is characterized by high density and low density of hydroxyl groups on the surface.

  The aforementioned nitride can be obtained, for example, by heating the oxide together with a reducing agent such as carbon in a nitrogen atmosphere. In this case, it is very important how the temperature distribution in the reactor is made uniform so as not to cause welding between particles while causing the reduction reaction. If the particles contain welded particles, give these powders velocity energy and disperse them by colliding them with the shielding plate. In the case of strong aggregates, disperse them in a solvent to form a slurry. In general, a method is used in which physical energy is applied and dispersed using an apparatus such as a high-pressure homogenizer.

  In addition to this method, the colloidal silica in the present invention can be produced based on, for example, the methods described in JP-A-6-199515 and JP-A-9-67114.

As content of a component (1), it is preferable that it is the range of 0.01-2.0 mass% with respect to the mass of the polishing liquid A used by this invention, and it is 0.1-1.5 mass%. A range is more preferable. Moreover, it is preferable that it is the range of 1.0-10.0 mass% with respect to the mass of the polishing liquid B used by this invention, and it is more preferable that it is the range of 1.0-5.0 mass%.
As content of a component (2), it is preferable that it is the range of 0.01-2.0 mass% with respect to the mass of the polishing liquid A used by this invention, and it is 0.1-1.5 mass%. A range is more preferable. Moreover, it is preferable that it is the range of 1.0-8.0 mass% with respect to the mass of the polishing liquid B used by this invention, and it is more preferable that it is the range of 1.0-5.0 mass%.

The total content of the component (1) and the component (2) in the polishing liquid of the present invention is preferably 0.01 to 2% by mass with respect to the mass of the polishing liquid A which is a polishing liquid for conductive films. 0.03-0.8 mass% is more preferable, and 0.05-0.5 mass% is still more preferable.
1.0-10 mass% is preferable with respect to the mass of the polishing liquid B which is polishing liquid for barrier metal films, 1.5-9.0 mass% is more preferable, 2.0-8.0 mass% is Further preferred.

The mass ratio of the mass M ₂ of the mass M ₁ and of component (1) in the polishing liquid (2) (M ₁ / M _2), the total content of the preferred range and above the particles of the components Within the range, 0.01-50 are preferable, It is more preferable that it is the range of 0.1-9.0, It is still more preferable that it is the range of 0.2-5.0.

[Oxidant]
Both the polishing liquid A and the polishing liquid B of the present invention contain component (3): an oxidizing agent as a compound capable of oxidizing the metal to be polished.
Examples of the oxidizing agent include hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, Examples include dichromate, permanganate, ozone water, silver (II) salt, and iron (III) salt.

Examples of the iron (III) salt include iron (III) in addition to inorganic iron (III) salts such as iron (III) nitrate, iron (III) chloride, iron (III) sulfate, and iron (III) bromide. The organic complex salt is preferably used.
In addition, when an organic complex salt of iron (III) is used, examples of complex-forming compounds constituting the iron (III) complex salt include acetic acid, citric acid, oxalic acid, salicylic acid, diethyldithiocarbamic acid, succinic acid, tartaric acid, and glycolic acid. Glycine, alanine, aspartic acid, thioglycolic acid, ethylenediamine, trimethylenediamine, diethylene glycol, triethylene glycol, 1,2-ethanedithiol, malonic acid, glutaric acid, 3-hydroxybutyric acid, propionic acid, phthalic acid, isophthalic acid In addition to 3-hydroxysalicylic acid, 3,5-dihydroxysalicylic acid, gallic acid, benzoic acid, maleic acid, and the like, and aminopolycarboxylic acids and salts thereof.

  Specific examples of the aminopolycarboxylic acid and salts thereof include ethylenediamine-N, N, N ′, N′-tetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-diaminopropane-N, N, N ′, N′— Tetraacetic acid, 1,2-diaminopropane-N, N, N ′, N′-tetraacetic acid, ethylenediamine-N, N′-disuccinic acid (racemic), ethylenediamine disuccinic acid (SS), N- (2 -Carboxylate ethyl) -L-aspartic acid, N- (carboxymethyl) -L-aspartic acid, β-alanine diacetic acid, methyliminodiacetic acid, nitrilotriacetic acid, cyclohexanediaminetetraacetic acid, iminodiacetic acid, glycol etherdiaminetetraacetic acid, ethylenediamine 1-N, N′-diacetic acid, ethylenediamine orthohydroxyphenylacetic acid, N, N-bis (2-hydride) Kishibenjiru) ethylenediamine -N, it includes and salts thereof such as N- diacetic acid. The kind of the counter salt is preferably an alkali metal salt or an ammonium salt, and particularly preferably an ammonium salt.

  Among the oxidizing agents described above, hydrogen peroxide, iodate, hypochlorite, chlorate, persulfate, and organic complex salts of iron (III) are preferable. In particular, when an organic complex salt of iron (III) is used, preferred complex-forming compounds are citric acid, tartaric acid, aminopolycarboxylic acid (specifically, ethylenediamine-N, N, N ′, N′-tetraacetic acid, Diethylenetriaminepentaacetic acid, 1,3-diaminopropane-N, N, N ′, N′-tetraacetic acid, ethylenediamine-N, N′-disuccinic acid (racemic), ethylenediaminedisuccinic acid (SS), N- ( 2-carboxylate ethyl) -L-aspartic acid, N- (carboxymethyl) -L-aspartic acid, β-alanine diacetic acid, methyliminodiacetic acid, nitrilotriacetic acid, iminodiacetic acid).

Of these, most preferably, the oxidizing agent contained in the polishing liquid A is hydrogen peroxide, persulfate, and iron (III) ethylenediamine-N, N, N ′, N′-tetraacetic acid, It is a complex of 3-diaminopropane-N, N, N ′, N′-tetraacetic acid and ethylenediamine disuccinic acid (SS form).
The most preferable oxidizing agent contained in the polishing liquid B is hydrogen peroxide.

The component (3) oxidizing agent in the present invention is preferably added at a ratio of 0.001 to 5.0 mol, based on 0.1 L of polishing liquid A for polishing the conductor film, and 0.1 to 4.0 mol. More preferably, it is contained in a proportion. That is, the amount of the oxidizing agent added to the polishing liquid A is preferably 0.001 mol or more in terms of polishing rate, and is preferably 5.0 mol or less in terms of planarization characteristics.
On the other hand, the component (3) oxidizing agent in the present invention is preferably added in a ratio of 0.001 to 0.5 mol with respect to 1 L of the polishing liquid B for polishing the barrier metal film, and 0.005 to 0. More preferably, it is contained in a proportion of 2 mol. That is, the amount of the oxidizing agent added to the polishing liquid B is preferably 0.001 mol or more from the viewpoint of polishing rate, and preferably 0.5 mol or less from the point of planarization characteristics.

[Arbitrary ingredients]
The polishing liquid in the present invention may contain arbitrary components as shown below. Examples of the optional component include a passive film forming agent (heterocyclic compound), an organic acid, a surfactant, and a water-soluble polymer. These components may be used alone or in combination of two or more.
Hereinafter, these optional components will be described.

(Passive film forming agent)
The polishing liquid in the present invention contains at least one heterocyclic compound as a compound that forms a passive film on the metal surface to be polished and suppresses a chemical reaction on the substrate, that is, as a passive film forming agent. You may do it.
Here, the “heterocyclic compound” is a compound having a heterocyclic ring containing one or more heteroatoms. A hetero atom means an atom other than a carbon atom or a hydrogen atom. Moreover, the heterocyclic ring means a cyclic compound having at least one hetero atom. Furthermore, a heteroatom means only those atoms that form part of a heterocyclic ring system, located external to the ring system, separated from the ring system by at least one non-conjugated single bond, Atoms that are part of a further substituent of the ring system are not meant.

  The hetero atom is preferably a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom, and more preferably a nitrogen atom, a sulfur atom, an oxygen atom, and a selenium atom. And particularly preferably a nitrogen atom, a sulfur atom and an oxygen atom, and most preferably a nitrogen atom and a sulfur atom.

First, in the present invention, a heterocyclic ring serving as a mother nucleus of a heterocyclic compound used as a passive film forming agent will be described.
The number of members of the heterocyclic ring of the heterocyclic compound used in the present invention is not particularly limited, and it may be a monocyclic compound or a polycyclic compound having a condensed ring. The number of members in the case of a single ring is preferably 3 to 8, more preferably 5 to 7, and particularly preferably 5 and 6. The number of rings in the case of having a condensed ring is preferably 2 to 4, more preferably 2 or 3.

Specific examples of these heterocyclic rings include the following. However, it is not limited to these.
That is, pyrrole ring, thiophene ring, furan ring, pyran ring, thiopyran ring, imidazole ring, pyrazole ring, thiazole ring, isothiazole ring, oxazole ring, isoxazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, pyrrolidine Ring, pyrazolidine ring, imidazolidine ring, isoxazolidine ring, isothiazolidine ring, piperidine ring, piperazine ring, morpholine ring, thiomorpholine ring, chroman ring, thiochroman ring, isochroman ring, isothiochroman ring, indoline ring, isoindoline ring , Pyridine ring, indolizine ring, indole ring, indazole ring, purine ring, quinolidine ring, isoquinoline ring, quinoline ring, naphthyridine ring, phthalazine ring, quinoxaline ring, quinazoline ring, cinnoline ring, pteridine ring, Kridine ring, perimidine ring, phenanthroline ring, carbazole ring, carboline ring, phenazine ring, anti-lysine ring, thiadiazole ring, oxadiazole ring, triazine ring, triazole ring, tetrazole ring, benzimidazole ring, benzoxazole ring, benzothiazole ring Benzothiadiazole ring, benzofuroxan ring, naphthimidazole ring, benzotriazole ring, tetraazaindene ring and the like, more preferably triazole ring and tetrazole ring.

Next, substituents that can be introduced into the heterocyclic ring will be described.
In the present invention, as described below, when a specific part is referred to as a “group”, the part may be one or more (up to the maximum possible number) even if the part itself is not substituted. It means that it may be substituted with a substituent. For example, “alkyl group” means a substituted or unsubstituted alkyl group.

Examples of the substituent that can be used in the heterocyclic compound used in the present invention include the following. However, it is not limited to these.
That is, 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, even if it is a polycyclic alkyl group such as a bicycloalkyl group) A methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regardless of the position of substitution), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group ( Examples of the carbamoyl group having a substituent include an N-hydroxycarbamoyl group, an N-acylcarbamoyl group, an N-sulfonylcarbamoyl group, an N-carbamoylcarbamoyl group, a thiocarbamoyl group, and an N-sulfamoylcarbamoyl group), a carbazoyl group. Carboxy group or a salt thereof, oxalyl group, oxy Moyl group, cyano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including groups containing repeating ethyleneoxy group or propyleneoxy group units), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy group) Or aryloxy) carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, (alkyl group, aryl group, or heterocyclic group) amino group, acylamino group, sulfonamido group, ureido group, thioureido group, N-hydroxy Ureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) Sulfonylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (for example, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group) Group), isocyano group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl Group, a sulfo group or a salt thereof, a sulfamoyl group (the sulfamoyl group having a substituent is, for example, an N-acylsulfamoyl group or an N-sulfonylsulfamoyl group) or a salt thereof, a phosphino group, a phosphinyl group, a phosphini Luoxy group, phosphinylamino group, silyl group, etc. Is mentioned.

The active methine group means a methine group substituted with two electron-withdrawing groups. Examples of the electron-withdrawing group include an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, and an alkyl group. A sulfonyl group, an arylsulfonyl group, a sulfamoyl group, a trifluoromethyl group, a cyano group, a nitro group, and a carbonimidoyl group are meant. Two electron-withdrawing groups may be bonded to each other to form a cyclic structure.
Moreover, the salt in the above-mentioned substituent means a salt formed by a cation such as alkali metal, alkaline earth metal or heavy metal, or an organic cation such as ammonium ion or phosphonium ion.

  Among these, preferable substituents include, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched, or cyclic alkyl group, and many like a bicycloalkyl group). A cyclic alkyl group or an active methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regarding the position of substitution), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, Heterocyclic oxycarbonyl group, carbamoyl group, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, carbazoyl group, oxalyl group , Oxamoyl group, cyano group, carboximide Ruyl group, formyl group, hydroxy group, alkoxy group (including groups containing ethyleneoxy group or propyleneoxy group unit), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy or aryloxy) carbonyloxy group, Carbamoloxy group, sulfonyloxy group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamide group, ureido group, thioureido group, N-hydroxyureido group, imide group, (alkoxy or aryloxy) carbonyl Amino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonylureido group, N-acylureido group, N-acyl Sulfamoylamino group, hydroxyamino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (eg, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group), isocyano group, imino group, mercapto group, (Alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or a salt thereof, sulfamoyl group, N -Acylsulfamoyl group, N-sulfonylsulfamoyl group or a salt thereof, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, silyl group and the like.

  More preferably, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, and a polycyclic alkyl group such as a bicycloalkyl group). Or an active methine group may be included), an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group (regarding the position of substitution).

Two of the above substituents may be bonded to each other to form a ring structure. Examples of the ring structure formed include an aromatic or non-aromatic hydrocarbon ring or a heterocyclic ring, and these can be further combined to form a polycyclic fused ring.
Specifically, for example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine Ring, pyrazine ring, pyrimidine ring, pyridazine ring, indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, Examples thereof include carbazole ring, phenanthridine ring, acridine ring, phenanthroline ring, thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, and phenazine ring.

Specific examples of the heterocyclic compound that can be particularly preferably used in the present invention include, but are not limited to, the following.
That is, in the polishing liquid A, 1-H tetrazole, 5 amino 1,2,3,4 tetrazole, 5 methyl 1,2,3,4 tetrazole, 1,2,3 triazole, 4 amino 1,2,3 triazole 4,5 diamino 1,2,3 triazole, 1,2,4 triazole, 3 amino 1,2,4 triazole, 3,5 diamino 1,2,4 triazole, 2 quinolinecarboxylic acid, and benzotriazole.
In the polishing liquid B, it is benzotriazole.

The heterocyclic compound in this invention may be used independently and may be used together 2 or more types.
Moreover, such a heterocyclic compound can be synthesized according to a conventional method, or a commercially available product may be used.

The heterocyclic compound (passive film forming agent) in the present invention is preferably added at a ratio of 0.01 to 100 mmol with respect to 1 L of polishing liquid A for polishing the conductor film, More preferably, it is contained in a proportion. That is, the amount of the heterocyclic compound added to the polishing liquid A is preferably 0.01 mmol or more in terms of planarization characteristics, and is preferably 100 mmol or less in terms of polishing rate.
On the other hand, the heterocyclic compound (passive film forming agent) in the present invention is preferably added at a ratio of 1.0 to 100 mmol with respect to 1 L of polishing liquid B for polishing the barrier metal film, and 5.0 More preferably, it is contained at a ratio of ˜50 mmol. That is, the amount of the heterocyclic compound added to the polishing liquid B is preferably 1.0 mmol or more in terms of planarization characteristics, and preferably 100 mmol or less in terms of polishing rate.

(Organic acid)
The polishing liquid in the present invention preferably further contains an organic acid. The organic acid here is a compound having a structure different from that of the oxidant used to oxidize the metal, and does not include an acid that functions as the oxidant described above. The organic acid here has an action of promoting oxidation, adjusting pH, and buffering agent.

As the organic acid, one selected from the following group is more suitable.
That is, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methyl Hexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, apple Examples thereof include acids, tartaric acid, citric acid, lactic acid, and salts thereof such as ammonium salts and alkali metal salts, sulfuric acid, nitric acid, ammonia, ammonium salts, and mixtures thereof.
Among these, formic acid, malonic acid, malic acid, tartaric acid, and citric acid are suitable for a laminated film including at least one metal layer selected from copper, copper alloys, and copper or copper alloy oxides. It is.

  The amino acid is preferably water-soluble. Those selected from the following group are more suitable. For example, glycine, dihydroxyethylglycine, tricine, L-alanine, β-alanine, L-2-aminobutyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-isoleucine, L-alloisoleucine, L-phenylalanine, L-proline, sarcosine, L-ornithine, L-lysine, taurine, L-serine, L-threonine, L-allothreonine, L-homoserine, L-tyrosine, 3,5-diiodo-L-tyrosine , Β- (3,4-dihydroxyphenyl) -L-alanine, L-thyroxine, 4-hydroxy-L-proline, L-cysteine, L-methionine, L-ethionine, L-lanthionine, L-cystathionine, L- Cystine, L-cysteic acid, L-aspartic acid, L-glutamic acid, S- (carboxyl Cymethyl) -L-cystine, 4-aminobutyric acid, L-asparagine, L-glutamine, azaserine, L-arginine, L-canavanine, L-citrulline, δ-hydroxy-L-lysine, creatine, L-quinurenin, L- Containing at least one of amino acids such as histidine, 1-methyl-L-histidine, 3-methyl-L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II, and antipine. Is desirable.

Among these organic acids, the polishing liquid A for polishing the conductive film includes glycolic acid, oxalic acid, malonic acid, succinic acid, malic acid, tartaric acid, citric acid, lactic acid, glycine, dihydroxyethylglycine, tricine, L- Alanine, β-alanine, L-valine, L-phenylalanine, L-lysine, L-serine, and L-histidine are preferable, and glycine, L-alanine, dihydroxyethylglycine, tricine, oxalic acid, malic acid are particularly preferable. preferable.
The polishing liquid B for polishing the barrier metal film includes glycolic acid, oxalic acid, malonic acid, succinic acid, malic acid, tartaric acid, citric acid, lactic acid, glycine, dihydroxyethylglycine, tricine, L-alanine, β- Alanine, L-valine, L-phenylalanine, L-lysine, L-serine, and L-histidine are preferable, and lactic acid, glycolic acid, and tartaric acid are particularly preferable.

The organic acid in the present invention is preferably added in a proportion of 0.01 to 0.5 mol, and contained in a proportion of 0.05 to 0.3 mol, with respect to 1 L of polishing liquid A for polishing the conductor film. More preferably. That is, the amount of the organic acid added to the polishing liquid A is preferably 0.01 mol or more in terms of polishing rate, and preferably 0.5 mol or less in terms of planarization characteristics.
On the other hand, the organic acid in the present invention is preferably added at a ratio of 0.05 to 0.7 mol, and a ratio of 0.1 to 0.5 mol, with respect to 1 L of the polishing liquid B for polishing the barrier metal film. More preferably, it is contained. That is, the amount of the organic acid added to the polishing liquid B is preferably 0.05 mol or more in terms of polishing rate, and is preferably 0.7 mol or less in terms of planarization characteristics and scratch points.

(Surfactant and / or hydrophilic compound)
The polishing liquid in the present invention preferably contains a surfactant and / or a hydrophilic compound. Both the surfactant and the hydrophilic compound (including the hydrophilic polymer) have an action of reducing the contact angle of the surface to be polished, and an action of promoting uniform polishing.

As the surfactant and the hydrophilic compound to be used, those selected from the following group are suitable.
Examples of the anionic surfactant include carboxylate, sulfonate, sulfate ester salt and phosphate ester salt. Examples of the carboxylate salt include soap, N-acyl amino acid salt, polyoxyethylene or polyoxypropylene alkyl ether carboxyl. Acid salt, acylated peptide; as sulfonate, alkyl sulfonate, alkyl benzene and alkyl naphthalene sulfonate, naphthalene sulfonate, sulfosuccinate, α-olefin sulfonate, N-acyl sulfonate; sulfate ester Salts include sulfated oil, alkyl sulfates, alkyl ether sulfates, polyoxyethylene or polyoxypropylene alkyl allyl ether sulfates, alkyl amide sulfates; phosphate ester salts such as alkyl phosphates, polyoxyethylene or polyoxypropyls. Can pyrene alkyl allyl ether phosphates.

  As cationic surfactant, aliphatic amine salt, aliphatic quaternary ammonium salt, benzalkonium chloride salt, benzethonium chloride, pyridinium salt, imidazolinium salt; carboxybetaine type, aminocarboxylate as amphoteric surfactant And imidazolinium betaine, lecithin, and alkylamine oxide.

Nonionic surfactants include ether type, ether ester type, ester type and nitrogen-containing type. Ether type includes polyoxyethylene alkyl and alkylphenyl ether, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene poly Examples include oxypropylene block polymer, polyoxyethylene polyoxypropylene alkyl ether, ether ester type, glycerin ester polyoxyethylene ether, sorbitan ester polyoxyethylene ether, sorbitol ester polyoxyethylene ether, ester type, Polyethylene glycol fatty acid ester, glycerin ester, polyglycerin ester, sorbitan ester, propylene glycol ester , Sucrose esters, nitrogen-containing type, fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkyl amide, and the like.
In addition to these, fluorine-based surfactants and the like can also be used.

  Furthermore, as other surfactants and hydrophilic compounds (including hydrophilic polymers), esters such as glycerin ester, sorbitan ester, methoxyacetic acid, ethoxyacetic acid, 3-ethoxypropionic acid and alanine ethyl ester; polyethylene glycol, Polypropylene glycol, polytetramethylene glycol, polyethylene glycol alkyl ether, polyethylene glycol alkenyl ether, alkyl polyethylene glycol, alkyl polyethylene glycol alkyl ether, alkyl polyethylene glycol alkenyl ether, alkenyl polyethylene glycol, alkenyl polyethylene glycol alkyl ether, alkenyl polyethylene glycol alkenyl ether, Polypropylene glycol alkyl Ethers such as polypropylene glycol alkenyl ether, alkyl polypropylene glycol, alkyl polypropylene glycol alkyl ether, alkyl polypropylene glycol alkenyl ether, alkenyl polypropylene glycol, alkenyl polypropylene glycol alkyl ether and alkenyl polypropylene glycol alkenyl ether; alginic acid, pectic acid, carboxymethyl cellulose, Polysaccharides such as curdlan and pullulan; amino acid salts such as glycine ammonium salt and glycine sodium salt; polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polyamide Acid, polymaleic acid Polyitaconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, polyacrylic acid ammonium salt, polyacrylic acid sodium salt, polyamic acid, polyamic acid ammonium salt, polyamic acid sodium salt And polycarboxylic acids such as polyglyoxylic acid and salts thereof; vinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone and polyacrolein; methyl taurate ammonium salt, methyl taurate sodium salt, methyl sodium sulfate salt, ethyl ammonium sulfate salt, sulfuric acid Butyl ammonium salt, vinyl sulfonic acid sodium salt, 1-allyl sulfonic acid sodium salt, 2-allyl sulfonic acid sodium salt, methoxymethyl sulfonic acid sodium salt, ethoxy Sulfonic acid and its salts such as methylsulfonic acid ammonium salt, 3-ethoxypropylsulfonic acid sodium salt, methoxymethylsulfonic acid sodium salt, ethoxymethylsulfonic acid ammonium salt, 3-ethoxypropylsulfonic acid sodium salt and sulfosuccinic acid sodium salt; Examples include amides such as propionamide, acrylamide, methylurea, nicotinamide, succinic acid amide and sulfanilamide.

  Among the compounds exemplified above, for the polishing liquid A, cyclohexanol, polyoxyethylene alkyl ether carboxylate, alkyl sulfonate, alkyl benzene sulfonate, polyoxyethylene alkyl allyl ether sulfate, polyoxyethylene alkyl Allyl ether phosphate is more preferable, and for polishing liquid B, polyoxyethylene alkyl ether carboxylate, alkylbenzene sulfonate, polyoxyethylene alkyl allyl ether sulfate, and polyoxyethylene alkyl allyl ether phosphate are more preferable. .

  However, in the case where the substrate to which the polishing liquid containing the above compound is applied is a silicon substrate for a semiconductor integrated circuit or the like, contamination with alkali metal, alkaline earth metal, halide, etc. is not preferable. It is preferable to use a salt. On the other hand, this is not the case when the substrate is a glass substrate or the like.

The addition amount of the surfactant and / or the hydrophilic compound is 0.0001 g to 0.05 g in 1 L of the polishing liquid A used for polishing (that is, the diluted polishing liquid when diluted with water or an aqueous solution). It is preferable to be 0.0005 g to 0.01 g, and it is particularly preferable to be 0.001 g to 0.007 g. That is, the addition amount of the surfactant and / or the hydrophilic compound is preferably 0.0001 g or more from the viewpoint of obtaining a sufficient effect, and preferably 0.1 g or less from the viewpoint of preventing a decrease in the CMP rate.
Moreover, it is preferable to set it as 0.0001g-0.1g in 1L of polishing liquid B at the time of using for grinding | polishing (namely, when diluted with water or aqueous solution), 0.0005g-0. The amount is more preferably 05 g, and particularly preferably 0.001 g to 0.01 g. That is, the addition amount of the surfactant and / or the hydrophilic compound is preferably 0.0001 g or more from the viewpoint of obtaining a sufficient effect, and preferably 0.1 g or less from the viewpoint of preventing a decrease in the CMP rate.

(Inorganic acid, alkali agent, buffer)
The polishing liquid in the present invention can contain an inorganic acid, an alkali agent, and further a buffer from the viewpoint of suppressing pH fluctuations, as necessary, for pH adjustment.

  Examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, phosphoric acid, and carbonic acid. Among these, sulfuric acid, phosphoric acid, and nitric acid are preferable for inclusion in the polishing liquid A, and sulfuric acid, phosphoric acid, and nitric acid are preferable for inclusion in the polishing liquid B.

  Alkaline agents and buffering agents include organic ammonium hydroxides such as ammonia, ammonium hydroxide and tetramethylammonium hydroxide, non-metallic alkaline agents such as alkanolamines such as diethanolamine, triethanolamine, triisopropanolamine, Alkali metal hydroxide such as sodium hydroxide, potassium hydroxide, lithium hydroxide, carbonate, phosphate, borate, tetraborate, hydroxybenzoate, glycyl salt, N, N-dimethylglycine salt , Leucine salt, norleucine salt, guanine salt, 3,4-dihydroxyphenylalanine salt, alanine salt, aminobutyrate, 2-amino-2-methyl-1,3-propanediol salt, valine salt, proline salt, trishydroxyamino Use methane salt, lysine salt, etc. It is possible.

  Specific examples of alkaline agents and buffering agents include ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, trisodium phosphate, tripotassium phosphate, phosphorus Disodium acid, dipotassium phosphate, sodium borate, potassium borate, sodium tetraborate (borax), potassium tetraborate, sodium o-hydroxybenzoate (sodium salicylate), potassium o-hydroxybenzoate, 5 -Sodium sulfo-2-hydroxybenzoate (sodium 5-sulfosalicylate), potassium 5-sulfo-2-hydroxybenzoate (potassium 5-sulfosalicylate), ammonium hydroxide and the like.

  Particularly preferable alkaline agents and buffering agents are ammonia, ammonium hydroxide, lithium hydroxide and tetramethylammonium hydroxide for the polishing liquid A, and ammonia and ammonium hydroxide for the polishing liquid B.

The pH of the polishing liquid A and the polishing liquid B used in the present invention is preferably 2-7.
The pH of the polishing liquid used for polishing (that is, the diluted polishing liquid when diluted with water or an aqueous solution) is preferably 3.0 to 7.0 in the polishing liquid A, and preferably 3.5 to 6 .5 is more preferred. In the polishing liquid B, 2.0-5.0 are preferable and 2.5-4.5 are more preferable.

(Dispersion medium)
In the polishing liquid A and the polishing liquid B in the present invention, water alone or water as a main component (50 to 99% by mass in the dispersion medium) is used as a dispersion medium, and water-soluble organic materials such as alcohol and glycol. What mix | blended the solvent as a subcomponent (1-30 mass%) can be used.
The water is preferably pure water or ion-exchanged water that does not contain macro particles as much as possible.
Examples of the alcohol include methyl alcohol, ethyl alcohol, and isopropyl alcohol, and examples of the glycol include ethylene glycol, tetramethylene glycol, diethylene glycol, propylene glycol, and polyethylene glycol.
Among these, a preferable example that can be contained in the polishing liquid A is pure water, and a preferable example that can be contained in the polishing liquid B is pure water.

In the polishing liquid A, the content of the dispersion medium in the polishing liquid is 90.0 to 99.9% by mass, preferably 94.0 to 99.0% by mass. 90.0 mass% or more is preferable from a viewpoint of the supply property of the polishing liquid onto the substrate, and 99.9 mass% or less is preferable from the viewpoint of a polishing rate.
Moreover, in the polishing liquid B, it is 80.0-95.0 mass%, Preferably it is 85.0-90.0 mass%. From the viewpoint of supplying the polishing liquid onto the substrate, 80.0% by mass or more is preferable, and from the viewpoint of polishing rate, 95.0% by mass or less is preferable.

  In the present invention, the polishing liquid A and the polishing liquid B, except for controlling the concentration of particles, adsorb to and react with any polishing liquid, the solubility of the polishing metal, and the surface to be polished. Depending on the electrochemical properties, the dissociation state of the functional group of the compound, the stability as a liquid, and the like, it is preferable to set the compound species, the addition amount and pH, and the dispersion medium in a timely manner.

[Semiconductor integrated circuit having a barrier metal film and a conductor film (wiring metal raw material)]
The object to be polished by the above-described polishing liquid in the present invention, that is, the semiconductor integrated circuit having the barrier metal film and the conductor film, preferably has the following wiring.
In the present invention, the object to be polished is preferably a wiring made of copper metal and / or a copper alloy in a semiconductor such as an LSI, and particularly a wiring made of a copper alloy is preferable. Furthermore, the copper alloy containing silver is preferable among copper alloys. The silver content contained in the copper alloy is preferably 40% by mass or less, particularly 10% by mass or less, more preferably 1% by mass or less, and copper containing silver in the range of 0.00001 to 0.1% by mass. Exhibits the most excellent effect in alloys.

(Wiring thickness)
In the present invention, the semiconductor to be polished with the above-described polishing liquid is preferably an LSI having a wiring with a half pitch of 0.15 μm or less in a DRAM device system, for example, and 0.10 μm or less. It is more preferable that the wiring is 0.09 μm or less.
On the other hand, in the MPU device system, an LSI having a wiring with a half pitch of 0.12 μm or less is preferable, a wiring of 0.09 μm or less is more preferable, and a wiring of 0.07 μm or less is preferable. Is more preferable.
For these LSIs, the above-described polishing liquid exhibits particularly excellent effects.

(Barrier metal film)
The object to be polished by the polishing liquid described above has a barrier metal film for preventing copper diffusion between a conductor film (wiring made of copper metal and / or copper alloy) and an insulating film described later. Have. The material constituting the barrier metal film is preferably a low-resistance metal material, and may be a laminated structure of a plurality of materials.
The material constituting the barrier metal film is preferably at least one selected from the group consisting of TiN, TiW, Ta, TaN, W, WN, and Ru, and more preferably Ta and / or TaN.

(Insulating film)
It is preferable that the object to be polished by the polishing liquid has an insulating film. As this insulating film, an inorganic insulating film or an organic insulating film can be applied. Specifically, as the insulating film in the present invention, an inorganic insulating film such as a silicon oxide film manufactured by a constant pressure CVD method or a plasma CVD method can be used. In addition, an organic insulating film obtained by a coating method having a hydrolyzed product of tetraalkoxylane as a main component, or an organic insulating film having a low relative dielectric constant having a polyorganosiloxane called an organic SOG as a main component can also be used. .

(Wafer)
The wafer to be polished with the polishing liquid in the present invention preferably has a diameter of 200 mm or more, particularly preferably 300 mm or more. The effect of the present invention is remarkably exhibited when the thickness is 300 mm or more.

[Chemical mechanical polishing method]
Although the chemical mechanical polishing method is described below, the following steps are applied to both the first polishing step and the second polishing step.
In the present invention, as the first polishing step, after supplying the polishing liquid A onto the polishing surface plate on which the polishing pad is disposed and polishing the conductive film, without performing other processing steps (conditioning) or the like. As the second polishing step, the barrier metal film is polished by supplying the polishing liquid B onto the same polishing surface plate as that used in the first polishing step. Thereby, the barrier metal film and the conductor film can be continuously polished on one polishing surface plate.
In the present invention, in the first polishing step, the end point was that all the conductor film on the barrier metal film was removed and further overpolishing was performed at 30%. When the end point is reached, the supply of the polishing liquid A is stopped, thereby completing the first polishing step. Thereafter, the supply of the polishing liquid B onto the polishing surface plate starts, whereby the second polishing step is started.
In the second polishing step, the end point was determined by removing the barrier metal film on the insulating film and further polishing the insulating film by 30 nm.
The end points in the first polishing step and the second polishing step can both be detected by an eddy current end point detector.

As described above, in the polishing method of the present invention, the first polishing step and the second polishing step are continuously performed on the same polishing surface plate. The polishing pad disposed on this polishing surface plate is The same thing may be used by a 1st grinding | polishing process and a 2nd grinding | polishing process, and a different thing may be used. From the viewpoint of increasing the efficiency of the polishing treatment, it is preferable to use the same polishing pad in the first polishing step and the second polishing step.
Hereinafter, this chemical mechanical polishing method (hereinafter sometimes simply referred to as “polishing method”) will be described.

The polishing liquid in the present invention is (a) a concentrated liquid which is prepared by adding water to dilute to use the liquid, and (b) each component is prepared in the form of an aqueous solution described in the next section. There is an embodiment in which the mixture is mixed and diluted with water as necessary to obtain a use solution, and (c) an embodiment prepared as a use solution from the beginning.
In the chemical mechanical polishing method of the present invention, the working liquid of the polishing liquid prepared according to such an embodiment is supplied to one polishing pad on the polishing surface plate and brought into contact with the surface to be polished. In this method, polishing is performed by relatively moving the polishing pad.

As an apparatus used for polishing, there is a polishing surface plate in which a holder for holding a semiconductor substrate having a surface to be polished and a polishing pad are attached (a motor that can change the number of rotations is attached) A typical polishing apparatus can be used.
Here, as a polishing pad, 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 pressing pressure of the semiconductor substrate having the surface to be polished (film to be polished) against the polishing pad is preferably 0.1 to 15 kPa in the first polishing step. In order to satisfy the speed uniformity within the wafer surface and the flatness of the pattern, it is more preferably 1 to 7.0 kPa. In the second polishing step, it is preferably 0.1 to 15 kPa, and in order to satisfy the uniformity of the polishing rate within the wafer surface and the flatness of the pattern, it is more preferably 1 to 7.0 kPa. preferable.

Here, the supply rate of the polishing liquid is preferably 10 to 500 ml / min in the case of the first polishing step. In order to satisfy the in-plane uniformity of the polishing rate and the flatness of the pattern, 50 to 300 ml / min. It is more preferable that
In the case of the second polishing step, 10 to 500 ml / min is preferable, and in order to satisfy the in-plane uniformity of the polishing rate and the flatness of the pattern, 100 to 300 ml / min is more preferable.

  Further, while polishing is continued, the polishing liquid is continuously supplied to the polishing pad in the apparatus by a pump or the like. Although there is no restriction | limiting in this supply amount, it is preferable that the surface of a polishing pad is always covered with polishing liquid. After the first polishing step and the second polishing step in the present invention are finished and the polishing is finished, the semiconductor substrate after the polishing is thoroughly washed in running water, and then is washed on the semiconductor substrate using a spin dryer or the like. Remove water droplets adhering to and dry.

In the embodiments (a) and (b), the diluting aqueous solution used when obtaining the working liquid of the polishing liquid is the same as the aqueous solutions shown below.
The aqueous solution is water containing at least one of an oxidizing agent, an organic acid, and a surfactant in advance, and a component obtained by adding up the components contained in the aqueous solution and the components of the polishing liquid to be diluted is used for actual polishing. It becomes a component of the working liquid of the polishing liquid when used.
As described above, when diluting with an aqueous solution when using the solution, it is possible to mix components that are difficult to dissolve in the form of an aqueous solution, so that a more concentrated polishing liquid can be prepared. .

  As a method of diluting by adding water or an aqueous solution to the concentrated polishing liquid as in the aspect (a), a pipe for supplying the concentrated polishing liquid and a pipe for supplying the water or the aqueous solution in the polishing apparatus. Are preferably mixed and mixed in the middle. The polishing liquid mixed and diluted in this way is supplied to the polishing pad to perform polishing. For mixing the liquid, a method in which the liquids collide with each other through a narrow passage under pressure, a method in which a filling such as a glass tube is filled in the pipe, a flow of the liquid is separated, and the liquid flow is repeatedly performed, Conventional methods such as a method of providing blades that rotate with power in the pipe can be employed.

  As a method of polishing while diluting the concentrated polishing liquid with water or an aqueous solution, etc., a pipe for supplying the polishing liquid and a pipe for supplying water or an aqueous solution are independently provided in the polishing apparatus, and a predetermined amount is provided from each. The liquid is supplied to the polishing pad, and the polishing is performed while mixing by the relative movement of the polishing pad and the surface to be polished. It is also possible to apply a method in which a predetermined amount of the concentrated polishing liquid and water or an aqueous solution are mixed in one container and then the mixed polishing liquid is supplied to the polishing pad to perform polishing.

As in the embodiment (b), the component to be contained in the polishing liquid is divided into at least two components, and when these are used, if necessary, diluted with water or an aqueous solution to dilute the polishing liquid. It is also suitable in the present invention to prepare a working solution.
In this case, specifically, for example, an oxidant is used as one component (A), an organic acid, a surfactant, and water are used as one component (B). Then, a method of diluting the component (A) and the component (B) with water or an aqueous solution is used.
In addition, the low-solubility additive is divided into two components (A) and (B), the oxidizing agent and the surfactant are one component (A), and the organic acid, the surfactant and water are 1 It is possible to dilute the component (A) and the component (B) by adding water or an aqueous solution when using them as the two components (B).

In the case of the method of polishing while preparing the working liquid of the polishing liquid as in the above example, three pipes for supplying the component (A), the component (B) and water or an aqueous solution, respectively, into the polishing apparatus In order to dilute and mix, three pipes are connected to one pipe supplied to the polishing pad and mixed in the pipe.
It is also possible to combine two pipes and then connect another one pipe. This is suitable, for example, for a method in which a constituent component containing an additive that is difficult to dissolve is mixed with another constituent component, a mixing path is lengthened to ensure a dissolution time, and a pipe for water or an aqueous solution is further combined. It is.
The use liquid of the polishing liquid thus mixed is continuously supplied to the polishing pad on the polishing surface plate and brought into contact with the surface to be polished to move the surface to be polished and the polishing pad relative to each other so that polishing can be performed. Done.

  Further, as another mixing method in the polishing apparatus, as described above, each of the three pipes is directly guided to the polishing pad and mixed by the relative movement of the polishing pad and the surface to be polished. There is a method of mixing the constituent component (A), the constituent component (B), and water or an aqueous solution, and supplying the diluted polishing liquid to the polishing pad therefrom.

In the above-mentioned embodiment (b), when one component containing an oxidizing agent is made 40 ° C. or lower and the other components are heated in the range of room temperature to 100 ° C., and these are mixed, or When mixing these and further diluting by adding water or an aqueous solution, a method of setting the liquid temperature to 40 ° C. or lower can also be used. This method is a preferable method for increasing the solubility of the raw material having a low solubility constituting the polishing liquid because the solubility of the solute increases when the liquid temperature is high.
Moreover, since the oxidizing agent may be decomposed when the temperature of one constituent component including the oxidizing agent is increased to 40 ° C. or higher, as described above, one constituent component containing the other heated components and the oxidizing agent is included. It is desirable that the temperature be 40 ° C. or lower when the components are mixed or when these components are mixed and further diluted.

  As mentioned above, other components that do not contain an oxidant are heated and dissolved in the range from room temperature to 100 ° C., because the dissolved components are precipitated in the solution when the temperature drops, The polishing apparatus is preferably provided with a means for dissolving components that can be deposited by heating. For this, it is possible to employ a means for feeding a component liquid that has been heated and dissolved, or a means for stirring a liquid containing precipitates, feeding the liquid, and heating and dissolving the piping.

  As described above, in the present invention, the components of the polishing liquid may be divided into two or more parts and supplied to the polishing surface. In this case, it is preferable to divide and supply the component containing an oxide and the component containing an organic acid. Alternatively, the polishing liquid may be a concentrated liquid, and diluted water may be separately supplied to the polishing surface.

(Polishing pad)
The polishing pad used in the present invention may be a non-foamed structure pad or a foamed structure pad. The former uses a hard synthetic resin bulk material like a plastic plate for a pad. Further, the latter further includes three types of a closed foam (dry foam system), a continuous foam (wet foam system), and a two-layer composite (laminated system), and a two-layer composite (laminated system) is particularly preferable. Foaming may be uniform or non-uniform.

  Further, it may contain abrasive grains (for example, ceria, silica, alumina, resin, etc.) used for polishing. In addition, the hardness may be either soft or hard, and either may be used. In the laminated system, it is preferable to use a different hardness for each layer. The material is preferably non-woven fabric, artificial leather, polyamide, polyurethane, polyester, polycarbonate or the like. In addition, the surface contacting the polishing surface may be subjected to processing such as lattice grooves / holes / concentric grooves / helical grooves.

  Although the apparatus which can implement the polishing method of the present invention is not particularly limited, Mirror Mesa CMP, Reflexion CMP (Applied Materials), FREX200, FREX300 (Ebara Manufacturing), NPS3301, NPS2301 (Nikon), A-FP-310A, A -FP-210A (Tokyo Seimitsu), 2300 TERES (ram research), Momentum (novelas), etc. can be mentioned.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
<Abrasive particles>
As abrasive particles, colloidal silica particles prepared based on the methods described in the following publications were used.
Abrasive particles a: average particle size 15 nm, colloidal silica particles prepared based on the method described in JP-A-6-199515 b: average particle size 35 nm, based on the method described in JP-A-6-199515 Colloidal silica particle abrasive particles c prepared as described above: average particle size 55 nm, colloidal silica particle abrasive particles prepared based on the method described in JP-A-6-199515 d: average particle size 70 nm, JP-A-6-199515 Colloidal silica particles prepared on the basis of the method described in e): average particle size 200 nm, colloidal silica particles prepared on the basis of the method described in JP-A-9-67114

<Preparation of polishing liquid A>
After mixing the following components, the mixture was stirred and uniformly dispersed with a high-speed homogenizer to obtain polishing liquids A-1 to A-13. Moreover, the obtained polishing liquid was adjusted with aqueous ammonia and sulfuric acid to pH 7.0.

・ Abrasive particles (as listed in Table 1) (Amount to give the concentration as listed in Table 1)
・ Hydrogen peroxide (oxidant) 10g / L
・ Glycine 8g / L
・ Benzotriazole 0.1 g / L (solid content conversion)
・ Pure water The total volume is 1000 ml

<Evaluation of polishing rate>
The rate at which the polishing liquid A polished copper (copper polishing rate) was determined as follows.
An apparatus “FREX-300” manufactured by Ebara Corporation was used as a polishing apparatus, and the following polishing target wafer was polished under the following polishing conditions, and the polishing rate at that time was measured.
(Polishing conditions)
Table rotation speed: 104 rpm
-Head rotation speed: 105rpm
Polishing pressure: 14.0 kPa
Polishing pad: Rohm and Haas product number IC-1400 K-grv + A21
・ Slurry supply rate: 300 ml / min

The polishing rate was determined by converting the film thickness difference before and after polishing from the electric resistance value.
Specifically, the measurement was performed by polishing rate (nm / min) = (thickness of copper film before polishing−thickness of copper film after polishing) / polishing time.
The film thickness difference measurement was performed using VR-200 manufactured by Kokusai Denki Alpha Co., Ltd.
The wafer used for polishing was a blanket wafer with 12 inch (φ300 mm) copper film (on a silicon substrate, 1000 nm oxide film (insulating film), 25 nm Ta (barrier metal film), 1500 nm Cu film (conductor film) in this order). Is).
The results are shown in Table 1.

<Preparation of polishing liquid B>
After mixing the following components, the mixture was stirred and uniformly dispersed with a high-speed homogenizer to obtain polishing liquids B-1 to B-13. Moreover, the obtained abrasive | polishing agent composition was adjusted with ammonia water and a sulfuric acid, and was set to pH 4.0.

・ Abrasive particles (things listed in Table 2) (amounts resulting in the concentrations shown in Table 2)
・ Hydrogen peroxide (oxidant) 10g / L
・ Lactic acid 3g / L
・ Benzotriazole 1g / L (converted to solid content)
・ Pure water The total volume is 1000 ml

<Evaluation of polishing rate>
In the following manner, the rate at which the polishing liquid B polished copper, tantalum, or an oxide film (copper polishing rate, tantalum polishing rate, oxide film polishing rate) was determined.
Here, the polishing apparatus to be used, the polishing conditions, and the method for calculating the polishing rate are the same as those for obtaining the polishing rate of the polishing liquid A, except that the polishing target is changed to the one shown below.
The wafers used as objects to be polished are as follows.
When obtaining the copper polishing rate: Blanket wafer with 12 inch (φ300 mm) copper film (those formed on a silicon substrate in the order of 1000 nm oxide film (insulating film), 25 nm Ta (barrier metal film), 1500 nm Cu film (conductor film))
When obtaining the tantalum polishing rate: Blanket wafer with 12 inch (φ300 mm) tantalum film (thick film formed on a silicon substrate in the order of 1000 nm oxide film (insulating film) and 150 nm Ta (barrier metal film))
When obtaining the oxide film polishing rate: Blanket wafer with 12 inch (φ300 mm) oxide film (thickness of 1000 nm oxide film (insulating film) formed on a silicon substrate)

<Measurement of polishing time>
As a polishing apparatus, an apparatus “FREX-300” manufactured by Ebara Corporation is used, and a slurry (polishing liquid A and polishing liquid B) is supplied under the following conditions, and a conductive film and a barrier provided on the following wafer to be polished: The metal film was polished.
The polishing process is as shown below.
That is, after supplying the polishing liquid A onto the polishing pad disposed on the polishing surface plate to polish all the conductor film (first polishing step), the same polishing surface continuously disposed on the same polishing surface plate The polishing liquid B was supplied onto the pad to polish the barrier metal film (second polishing step), and then the polishing was performed through steps such as cleaning the surface to be polished with water polish.
The end point of the first polishing step using the polishing liquid A was a point where overpolishing corresponding to 30% was performed using an eddy current type end point detector attached to the polishing apparatus. Here, the supply of the polishing liquid A was stopped, the supply of the polishing liquid B was started, and the barrier metal film was continuously polished. Here, the end point of the second polishing step was a point where the barrier metal film was removed and the silicon oxide film was further polished by 30 nm.
As described above, the time required for polishing (polishing time required for the first polishing step + polishing time required for the second polishing step) was determined. The results are shown in Table 3 below.

(Polishing target)
Wafer to be polished: Pattern wafer with 12 inch (φ300 mm) copper film 754CMP003, manufactured by atdf (on the silicon substrate, a 500 nm oxide film is deposited and a pattern is formed thereon, and then a 25 nm Ta (barrier metal film), 1500 nm Cu film (conductor) Film))

(Polishing conditions)
Table rotation speed: 104 rpm
-Head rotation speed: 105rpm
Polishing pressure: 14.0 kPa
Polishing pad: Rohm and Haas product number IC-1400 K-grv + A21
・ Slurry supply rate: 300 ml / min

<Measurement of conductor film and remaining barrier metal film>
The exposed polished surface of the pattern wafer after the copper film (conductor film) and the tantalum film (barrier metal film) are not left on the insulating film or after the polishing is finished by the method described in the measurement of the polishing time. On the other hand, it measured visually using the differential interference type | formula optical microscope (MX-80, Olympus company make). The measurement results were evaluated in the following two stages.
○: No remaining copper film and tantalum film (no polishing residue)
X: Copper film and tantalum film remaining (polishing remaining)

<Measurement of scratches>
The scratches are evaluated by polishing a wafer to be polished (blanket wafer) shown below by the method described in the above-mentioned measurement of the polishing time, and the exposed polished surface after the polishing is finished with KLA Tencor. This was done by measuring a scratch of 0.2 μm or more present on the surface to be polished, using a manufactured foreign matter inspection apparatus SP1-TBI.
Wafer to be polished: Blanket wafer with 12 inch (φ300 mm) copper film (a 500 nm oxide film is deposited on a silicon substrate, and then a 25 nm Ta film (barrier metal film) and a 4000 nm Cu film (conductor film)) And in this order)

The number of scratches of 0.2 μm or more present on the surface to be polished was evaluated in the following three stages. The results are shown in Table 2 below.
○: Less than 10 Δ: 10 or more and less than 50 (allowable range)
×: 50 or more

<Dishing and erosion measurement>
The dishing and erosion on the exposed polished surface of the pattern wafer after the polishing was finished by the method described in the above measurement of the polishing time were measured using a contact level difference measuring device Dektak V320Si (Veeco).

As is apparent from Table 3, the barrier metal film is polished without performing the transport process after the conductor film is polished as in the embodiment, that is, continuously with one polishing platen and one polishing pad. In particular, it can be seen that polishing the conductor film and the barrier metal film reduces the amount of scratches and dishing on the surface to be polished, and enables high-quality polishing.
In this way, by using the polishing liquid A and the polishing liquid B in which two kinds of particles having different particle diameters are used, both the polishing speed and the flattening characteristics can be achieved, and one polishing surface plate and one polishing pad can be used. The conductor film and the barrier metal film can be continuously polished, and the cost can be reduced by greatly reducing the processing time.

Claims (6)

A chemical mechanical polishing method for polishing an object to be polished having a barrier metal film and a conductor film provided on the barrier metal film,
A first polishing step of polishing the conductor film using the polishing liquid A and a second polishing step of polishing the barrier metal film using the polishing liquid B are the same polishing constant in which the polishing pad is disposed. A chemical mechanical polishing method, which is carried out continuously on a board, and wherein the polishing liquid A and the polishing liquid B contain the following components (1) to (3).
Component (1): Particle component having an average particle size in the range of 60 to 150 nm determined by the dynamic light scattering method (2): Particle component having an average particle size in the range of 10 to 50 nm determined by the dynamic light scattering method ( 3): Oxidizing agent   The chemical mechanical polishing method according to claim 1, wherein the polishing pads used in the first polishing step and the second polishing step are the same.   The chemical mechanical polishing method according to claim 1 or 2, wherein the polishing liquid A and the polishing liquid B have a pH of 2 to 7. 4. The chemical mechanical polishing method according to claim 1, wherein the total content of the component (1) and the component (2) is within the following range.
Polishing liquid A: 0.01-2.0 mass% with respect to the mass of the polishing liquid A
Polishing liquid B: 1.0-10 mass% with respect to the mass of the polishing liquid B   The component (3) is hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, Any one of Claim 1 thru | or 4 selected from the group which consists of dichromate, permanganate, ozone water, silver (II) salt, and iron (III) salt The chemical mechanical polishing method according to claim 1.   The chemical mechanical polishing method according to claim 5, wherein the component (3) is hydrogen peroxide.