TW201712098A - Chemical mechanical polishing composition and chemical mechanical polishing method capable of performing high speed polishing reducing the corrosion of tungsten film surface - Google Patents

Abstract

To provide a chemical mechanical polishing aqueous dispersion and a chemical mechanical polishing method for grinding a to-be-treated surface of a treated object such as a semiconductor wafer provided with a metal-containing circuit layer, without reducing the polishing speed, and for reducing the corrosion of tungsten film surface. A chemical mechanical polishing composition which is characterized by comprising: (A) a compound represented by the following general formula (1) or a salt thereof; (B) a water-containing dispersion catalyst; (C) grinding particles; and (D) an oxidizing agent. In the above formula (1), R1 represents a group having an alkyl group having a substituted or unsubstituted alkyl group having 8 or more carbon atoms, R2 represents a hydrogen atom, a1-3C organic group having a hydroxyl group or a carboxyl group, R3 represents a1-3C alkyl groups.

Description

Chemical mechanical polishing composition and chemical mechanical polishing method

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

In recent years, with the increase in the definition of semiconductor devices, circuits formed in semiconductor devices and circuit layers composed of plugs and the like have been progressing in a small manner. Along with this, a means for flattening the circuit layer by chemical mechanical polishing (hereinafter also referred to as "CMP") is used. In this method, for example, a conductive metal such as aluminum, copper or tungsten is deposited on a fine groove or hole of an insulating film such as ruthenium oxide provided on a semiconductor substrate by sputtering or plating. The CMP removes the over-laminated metal film to allow the metal to remain only in the portion of the fine groove or the hole (see, for example, Patent Document 1).

In this program, in particular, a material such as a plug that energizes the circuit in the vertical direction is used as tungsten having excellent embedding property. Chemical mechanical polishing for forming a tungsten plug, a first polishing treatment step of polishing a tungsten layer mainly provided on an insulating film, and a second polishing treatment for polishing a barrier metal film such as a tungsten plug or titanium and an insulating film step.

For chemical mechanical polishing of such a tungsten layer and a tungsten plug (hereinafter also referred to as "tungsten film"), for example, Patent Document 2 discloses a semiconductor polishing composition as a finishing polishing corresponding to the first polishing treatment step. The semiconductor polishing composition used in the previous stage contains abrasive grains such as colloidal cerium oxide, in order to prevent high polishing rate and high reactivity of the amine compound of the polishing accelerator and cerium, resulting in rough surface of the wafer after polishing. A basic low molecular compound such as an amine compound or a water-soluble polymer compound having a nitrogen-containing group such as polyethyleneimine.

Further, Patent Document 3 discloses a chemical mechanical polishing method for a tungsten-containing substrate, using an etchant for tungsten such as an oxidizing agent or an etching inhibitor of tungsten such as a specific polymer having a nitrogen atom at a content of 1 to 1,000 ppm. And a chemical mechanical polishing composition containing water for polishing. The chemical mechanical polishing composition used in the polishing method may contain an abrasive such as colloidal cerium oxide as an optional component, and a monopersulfate (SO ₅ ^2- ) or dipersulfate (S ₂ O ₈ ^{2 ). -} ) and other compounds.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 2002-518845

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-19093

[Patent Document 3] Japanese Patent Publication No. 2008-503875

However, there has not been obtained a tungsten film grinding water dispersion which can achieve high polishing speed while reducing corrosion of the surface to be polished.

Accordingly, in order to solve the above problems, a chemical mechanical polishing composition and a chemical mechanical polishing method for polishing a metal containing tungsten or the like in a semiconductor device manufacturing step are provided in the aspects related to the present invention. The object to be processed such as the semiconductor wafer of the circuit layer, in particular, the surface to be treated in which the tungsten film of the object to be processed and the insulating film such as the yttrium oxide film coexist, and the polishing rate is not lowered, and the corrosion of the surface of the tungsten film can be reduced.

The present invention has been made to solve at least a part of the above problems, and can be realized by the following aspects or application examples.

[Application 1]

An aspect of the composition for chemical mechanical polishing according to the present invention, which comprises: (A) a compound represented by the following general formula (1) or a salt thereof; (B) a dispersion medium containing water; (C) ) abrasive particles; and (D) oxidizing agents, (In the above formula (1), R1 represents a group having a substituted or unsubstituted alkyl group having 8 or more carbon atoms, and R2 represents a hydrogen atom, an organic group having 1 to 3 carbon atoms having a hydroxyl group or a carboxyl group, and R3 represents a carbon number. 1~3 of the alkyl group).

[Applicable Example 2]

The chemical mechanical polishing composition according to Application Example 1 may contain (D) at least one metal ion selected from the group consisting of Fe ²⁺ , Fe ³⁺ , and Cu ²⁺ .

[Applicable Example 3]

In the chemical mechanical polishing composition according to the first aspect or the second aspect, the ratio (A)/(D) of the component (A) to the component (D) may be 0.005 to 0.1.

[Applicable Example 4]

The chemical mechanical polishing composition according to any one of Application Examples 1 to 3, wherein the pH is from 1.5 to 3.5.

[Applicable Example 5]

The chemical mechanical polishing composition according to any one of Application Examples 1 to 4 may be used for polishing at least one type of substrate selected from the group consisting of tungsten and a tungsten alloy.

[Applicable Example 6]

An aspect of the chemical mechanical polishing method according to the present invention is characterized in that the object to be processed in which the circuit layer containing metal is provided is polished by using the chemical mechanical polishing composition according to any one of Application Examples 1 to 5. .

By using the composition for chemical mechanical polishing according to the present invention, it is possible to polish a target object such as a semiconductor wafer provided with a circuit layer of a metal such as tungsten in the semiconductor device manufacturing step, in particular, the object to be processed. The surface to be treated in which the tungsten film and the insulating film such as the ruthenium oxide film coexist, and the polishing rate is not lowered, and the corrosion of the surface of the tungsten film can be reduced.

10‧‧‧矽 substrate

12‧‧‧矽Oxide film

14‧‧‧Tungsten film

20‧‧‧Electric recess

42‧‧‧Blurry supply nozzle

44‧‧‧Blurry (composition for chemical mechanical polishing)

46‧‧‧ polishing cloth

48‧‧‧ turntable

50‧‧‧Semiconductor substrate

52‧‧‧ Carrying head

54‧‧‧Water supply nozzle

56‧‧‧Finisher

100‧‧‧Processed body

200‧‧‧Chemical mechanical grinding device

Fig. 1 is a schematic cross-sectional view showing a suitable object to be processed when the chemical mechanical polishing method according to the embodiment is used.

Fig. 2 is a perspective view showing a chemical mechanical polishing apparatus suitable for use in the chemical mechanical polishing method according to the embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail. The present invention is not limited to the embodiments described below, and various modifications that are carried out without departing from the scope of the invention are included in the invention.

Chemical mechanical polishing composition

A composition for chemical mechanical polishing according to an embodiment of the present invention, which comprises (A) a compound represented by the following general formula (1) or a salt thereof, (B) a dispersion medium containing water, (C) ) abrasive particles, and (D) oxidant. Hereinafter, each component and the like contained in the chemical mechanical polishing composition related to the present embodiment will be described.

(In the above formula (1), R1 represents a group having a substituted or unsubstituted alkyl group having 8 or more carbon atoms, and R2 represents a hydrogen atom, an organic group having 1 to 3 carbon atoms having a hydroxyl group or a carboxyl group, and R3 represents a carbon number. 1~3 of the alkyl group).

The chemical mechanical polishing composition to be used in the present embodiment is used for polishing a substrate to be provided with a circuit layer containing a metal such as tungsten, as will be described later.

1.1. (A) ingredients

The chemical mechanical polishing composition according to the present embodiment contains (A) a compound represented by the following general formula (1) or a salt thereof.

(In the above formula (1), R1 represents a group having a substituted or unsubstituted alkyl group having 8 or more carbon atoms, and R2 represents a hydrogen atom, an organic group having 1 to 3 carbon atoms having a hydroxyl group or a carboxyl group, and R3 represents a carbon number. 1~3 of the alkyl group).

In the chemical mechanical polishing composition according to the present embodiment, the effect of the component (A) is not necessarily clear, but it can be estimated as follows. That is, the component (A) has a function as a surfactant, and the ionic unit containing a nitrogen atom is adsorbed to the metal surface by interaction with the metal surface of the object to be treated, and the long-chain unit of R1 is suppressed as described later ( D) Chemical reactions caused by oxidants and the like. Thereby, the component (A) can function as an anticorrosive agent for the metal surface of the object to be processed, and a resist film having a multilayer structure can be formed on the surface to be treated of the circuit layer containing a metal such as tungsten. In this way, the component (A) has a function of balancing the (C) abrasive grains of the chemical mechanical polishing composition or the oxidizing power generated by adjusting the (D) oxidizing agent, etc., and therefore it is considered that the surface to be processed can be polished without lowering The grinding speed reduces the corrosion of the treated surface.

The group of the substituted or unsubstituted alkyl group having 8 or more carbon atoms of R1 in the above general formula (1) may, for example, be a linear or branched alkyl group having 8 or more carbon atoms or a straight carbon having 8 or more carbon atoms. An amino group of a chain or a branched alkyl group, an amine group having a linear or branched alkyl group having 8 or more carbon atoms, an alkyl group having a linear or branched alkyl group having 8 or more carbon atoms, or the like. In particular, from the viewpoint of the anticorrosive agent, a linear alkyl group having 8 or more carbon atoms, a decylamino group having a linear alkyl group having 8 or more carbon atoms, and an amine having a linear alkyl group having 8 or more carbon atoms are preferable. base. When the carbon number is 8 or more, the balance of the oxidizing power of the composition can be adjusted to suppress the chemical reaction caused by the above (D) oxidizing agent. The effect is high, so the effect as a corrosion inhibitor for the metal surface is high.

R2 in the above general formula (1) is a hydrogen atom and an organic group having 1 to 3 carbon atoms having a hydroxyl group or a carboxyl group. Examples of the organic group having 1 to 3 carbon atoms and having a hydroxyl group or a carboxyl group include a hydroxyl group having 1 to 3 carbon atoms and a carboxyl group having 1 to 3 carbon atoms. The hydroxyl group having 1 to 3 carbon atoms is preferably a hydroxyethyl group or a hydroxymethyl group. The carboxyl group having 1 to 3 carbon atoms is preferably a carboxyethyl group or a carboxymethyl group.

In particular, the compound represented by the above general formula (1) or a salt thereof is preferably selected from the group consisting of sodium lauryl ammonium propionate, sodium lauryl ammonium dipropionate, sodium lauryl ammonium acetate, and sodium cocoamphoacetate. At least one of the constituent groups. In the case of using these compounds, the surface to be treated can be ground, and the polishing rate is not lowered, and the corrosion of the surface to be treated can be reduced. The above-exemplified compounds may be used alone or in combination of two or more.

The content of the component (A) is 0.0001% by mass or more and 0.5% by mass or less based on the total mass of the chemical mechanical polishing composition, and is preferably 0.001% by mass or more and 0.1% by mass or less, preferably 0.01% by mass or more and 0.05% by mass or less. the following. When the content ratio of the component (A) is in the above range, the surface to be treated can be polished, and the polishing rate can be reduced without reducing the corrosion of the surface to be treated.

1.2. (B) Dispersing media

The chemical mechanical polishing composition according to the present embodiment contains water as the (B) dispersion medium. (B) The dispersion medium is not limited as long as it contains water, and is preferably a solvent which does not affect the oxidizing power of the chemical mechanical polishing composition. Components other than water contained in the dispersion medium can be listed For example, an alcohol, an organic solvent compatible with water, and the like. (B) The dispersion medium is preferably water or a mixed medium of water and alcohol, and it is preferred to use only water.

In the case of a mixed medium containing a dispersion medium other than water and water, the content of water in the (B) dispersion medium is 80% by mass or more and 99% by mass or less based on the total mass of the chemical mechanical polishing composition. It is preferably 85 mass% or more and 98 mass% or less, preferably 90 mass% or more and 98 mass% or less. In the case where the content ratio of water is in the above range, the surface to be treated can be polished without lowering the polishing rate, and the corrosion of the surface to be treated can be reduced.

1.3. (C) abrasive grains

The chemical mechanical polishing composition according to the embodiment further contains (C) abrasive grains. (C) The abrasive grains include inorganic particles such as cerium oxide, cerium oxide, aluminum oxide, zirconium dioxide, and titanium oxide.

Examples of the cerium oxide particles include colloidal cerium oxide, fumed cerium oxide, and the like, and among these, colloidal cerium oxide is preferably used. From the viewpoint of reducing the polishing defects such as scratches, it is preferable to use a gel-like cerium oxide, for example, a product produced by the method described in JP-A-2003-109921. Further, a gelatinous surface which is surface-modified by a method as described in JP-A-2010-269985 or J. Ind. Eng. Chem., Vol. 12, No. 6, (2006) 911-917, etc., may also be used. Yttrium oxide.

In particular, a cationically modified colloidal ceria that introduces a cationic group on the surface of a colloidal ceria has excellent stability under acidic conditions. It is suitable for use in the present invention. A method of introducing a cationic group on the surface of the colloidal ceria can be exemplified by modifying the surface of the colloidal ceria with a decane coupling agent having a functional group chemically converted into a cationic group. Examples of such a decane coupling agent include aminopropyltrimethoxydecane, (aminoethyl)aminopropyltrimethoxydecane, aminepropyltriethoxydecane, aminepropyldimethylethoxydecane, and amine propylamine. Methyl diethoxy decane, aminobutyl triethoxy decane, and the like.

Further, a sulfonic acid-modified colloidal cerium oxide having a sulfonic acid group introduced into the surface of the colloidal cerium oxide can also be used. The method of introducing a sulfonic acid group on the surface of the colloidal ceria can be exemplified by modifying the surface of the colloidal ceria with a decane coupling agent having a functional group chemically converted to a sulfonic acid group, and then converting the functional group into a sulfonic acid group. Base method. Examples of such a decane coupling agent include a decane coupling agent having a mercapto group such as 3-mercaptopropyltrimethoxydecane, 2-mercaptoethyltrimethoxydecane or 2-mercaptoethyltriethoxydecane; A decane coupling agent having a thioether group such as triethoxymethanealkylpropyl)disulfide. The sulfonic acid group can be converted by oxidizing the sulfhydryl group or the thioether group of the decane coupling agent on the surface of the modified colloidal cerium oxide.

(C) The content of the abrasive grains is 0.1% by mass or more and 10% by mass or less based on the total mass of the chemical mechanical polishing composition, preferably 0.3% by mass or more and 8% by mass or less, preferably 0.5% by mass or more and 5 mass%. %the following. When the content ratio of the (C) abrasive grains is in the above range, corrosion of the surface to be treated having a tungsten film or the like can be reduced, and a practical polishing rate can be obtained.

1.4. (D) Oxidizer

The composition for chemical mechanical polishing associated with this embodiment contains (D) an oxidizing agent. In the chemical mechanical polishing composition according to the present embodiment, by containing the (D) oxidizing agent, the surface to be treated of the circuit layer containing the metal containing tungsten or the like can be oxidized, and the misalignment reaction with the polishing liquid component can be promoted. The treated surface produces a fragile modified layer with an easy to grind effect.

The (D) oxidizing agent may, for example, be ammonium persulfate, potassium persulfate, hydrogen peroxide, iron (III) nitrate, diammonium nitrate, hypochlorous acid, ozone, potassium periodate or peracetic acid. These (D) oxidizing agents may be used alone or in combination of two or more. Further, among these (D) oxidizing agents, in view of oxidizing power, protective film phase properties, ease of use, and the like, (D) oxidizing agent is preferably ammonium persulfate or hydrogen peroxide.

(D) The content of the oxidizing agent is preferably 0.1% by mass or more and 15% by mass or less based on the total mass of the chemical mechanical polishing composition, and is preferably 0.5% by mass or more and 10% by mass or less, preferably 1% by mass or more and 5% by mass or less. the following.

The ratio (A)/(D) of the component (A) to the component (D) is preferably 0.005 to 0.1, and preferably 0.01 to 0.05. When the ratio of the component (A) to the component (D) is in the above range, the surface to be treated can be polished, and the polishing rate can be reduced without reducing the corrosion of the surface to be treated.

1.5. (E) Metal ions

The chemical mechanical polishing composition to be used in the present embodiment preferably contains at least one metal ion selected from the group consisting of Fe ²⁺ , Fe ³⁺ , and Cu ²⁺ . When the (E) metal ion is further contained in the chemical mechanical polishing composition according to the embodiment, the surface of the circuit layer containing the metal containing tungsten or the like can be oxidized to promote the mismatch reaction with the polishing liquid component. A fragile modified layer is formed on the treated surface, and there is an easy grinding effect.

The compound containing (E) at least one metal ion selected from the group consisting of Fe ²⁺ , Fe ³⁺ , and Cu ²⁺ may be either an inorganic acid iron salt or an organic acid iron salt, and examples thereof include nitric acid. Iron (II or III), iron (II or III) sulfate, iron (III) ammonium sulfate, iron (III) perchlorate, iron (III) chloride, iron (III) citrate, iron ammonium citrate (III) ), ammonium (III) oxalate, copper (II) nitrate, copper (II) sulfate, and the like. These (E) metal ions may be used alone or in combination of two or more. Further, among these (E) metal ions, iron nitrate, iron sulfate, copper nitrate, and copper sulfate are preferred in consideration of oxidizing power, protective film phase properties, and ease of use.

The content of the metal ion is preferably 0.0001% by mass or more and 0.1% by mass or less, more preferably 0.0005% by mass or more and 0.01% by mass or less, and particularly preferably 0.001% by mass or more and 0.005% by mass or less based on the total mass of the chemical mechanical polishing composition. the following.

1.6. Other additives

In the chemical mechanical polishing composition according to the embodiment, a chelating agent, a water-soluble polymer, a pH adjuster, and the like may be further added as necessary. An additive such as a surfactant or an anticorrosive agent other than the compound represented by the above general formula (1). The following describes each additive.

1.6.1. (F) Chelating agent

The chemical mechanical polishing composition to be used in the present embodiment may be added with a (F) chelating agent. By adding (F) a chelating agent to the chemical mechanical polishing composition to which the present embodiment is applied, it is possible to oxidize the surface to be treated of the circuit layer containing a metal such as tungsten, and to promote a misalignment reaction with the polishing liquid component. A weak modified layer is formed on the treated surface, and the surface to be polished is easily polished.

Examples of the chelating agent include malonic acid, citric acid, citric acid, succinic acid, glutaric acid, adipic acid, adenine, histidine, ethylenediamine, 1,2,4-triazole, glycine, 1-Hydroxyethane-1,1-diphosphonic acid and the like. These chelating agents may be used alone or in combination of two or more. Further, in consideration of oxidizing power, protective film phase properties, ease of use, and the like, it is preferred to use citric acid, malonic acid, adipic acid, adenine, and histidine among these chelating agents.

The amount of the chelating agent to be added is preferably 1% by mass or less, and preferably 0.001% by mass or more and 0.1% by mass or less based on the total mass of the chemical mechanical polishing composition.

1.6.2. (G) Water soluble polymer

In the chemical mechanical polishing composition to which the embodiment is concerned, (G) a water-soluble polymer may be added. (G) The water-soluble polymer has a function of adsorbing on the surface of the surface to be polished to reduce polishing friction.

By adding (G) a water-soluble polymer to the composition for chemical mechanical polishing associated with this embodiment, it is possible to suppress the occurrence of dents or corrosion.

Examples of the water-soluble polymer include polyacrylamide, polyacrylic acid, polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneimine, polyallylamine, and hydroxyethylcellulose.

The amount of the water-soluble polymer to be added is preferably 0.005% by mass or less, and preferably 0.0001% by mass or more and 0.001% by mass or less based on the total mass of the chemical mechanical polishing composition.

In addition, the amount of the water-soluble polymer can be adjusted so that the viscosity of the chemical mechanical polishing composition is less than 10 mPa. s. If the chemical mechanical polishing composition has a viscosity of more than 10mPa. In the case of s, the polishing rate may be lowered, and the viscosity may become too high, and the chemical mechanical polishing composition may not be stably supplied to the polishing cloth. As a result, the temperature of the polishing cloth rises or the polishing unevenness (deterioration of the in-plane uniformity) may cause a change in the polishing rate or the dent.

1.6.3. pH adjuster

The composition for chemical mechanical polishing associated with this embodiment may contain a pH adjuster. Examples of the pH adjuster include acidic compounds such as maleic acid, nitric acid, sulfuric acid, and phosphoric acid. The pH of the chemical mechanical polishing composition to be used in the present embodiment is not particularly limited, and is preferably 1.5 or more and 3.5 or less. When the pH is in the above range, the tungsten film can be polished with an insulating film such as a ruthenium oxide film without lowering the polishing rate and reducing the corrosion of the surface to be processed. The deposited surface to be treated and the chemical mechanical polishing composition have good storage stability.

The content of the pH adjuster may be appropriately adjusted so as to be the above-mentioned pH. For example, the total mass of the chemical mechanical polishing composition is preferably 1% by mass or less, preferably 0.001% by mass or more and 0.1% by mass or less.

1.6.4. Surfactant

In the chemical mechanical polishing composition to be used in the present embodiment, a surfactant other than the compound represented by the above general formula (1) may be added as necessary. The surfactant has an effect of imparting a moderate viscosity to the chemical mechanical polishing composition. The viscosity of the chemical mechanical polishing water dispersion should be adjusted to 0.5 mPa at 25 °C. Above s is less than 10mPa. s.

The surfactant is not particularly limited, and an anionic surfactant, a cationic surfactant, a nonionic surfactant, and the like are not particularly limited.

Examples of the anionic surfactant include a carboxylate, a sulfonate, a sulfate, a phosphate, and the like. The carboxylate may, for example, be a fatty acid soap, an alkyl ether carboxylate or the like. The sulfonate may, for example, be an alkylbenzenesulfonate, an alkylnaphthalenesulfonate or an α-olefinsulfonate. Examples of the sulfate include a high carbon alcohol sulfate, an alkyl sulfate, and the like. The phosphate may, for example, be an alkyl phosphate or the like.

The cationic surfactant may, for example, be an aliphatic amine salt or an aliphatic ammonium salt.

Examples of nonionic surfactants include ether-type interface activities. A surfactant, an ether ester type surfactant, an ester type surfactant, an acetylene surfactant, and the like. The ether ester type surfactant may, for example, be a polyethylene oxide ether of a glyceride or the like. The ester type surfactant may, for example, be a polyethylene glycol fatty acid ester, a glycerin ester or a sorbitan ester. Examples of the acetylene-based surfactant include an acetylene alcohol, an acetylene glycol, an ethylene oxide adduct of acetylene glycol, and the like.

These surfactants may be used alone or in combination of two or more.

The content of the surfactant is preferably 1% by mass or less, and preferably 0.001 to 0.1% by mass based on the total mass of the chemical mechanical polishing composition. When the amount of the surfactant added is within the range, the insulating film such as the tungsten film or the hafnium oxide film is polished and removed, and a smooth polished surface can be obtained.

1.6.5. Corrosion inhibitor

In the chemical mechanical polishing composition according to the embodiment, an anti-corrosion agent may be further added as necessary. Examples of the corrosion inhibitor include benzotriazole and derivatives thereof. Here, the benzotriazole derivative means one or two or more hydrogen atoms which the benzotriazole has, for example, a carboxyl group, a methyl group, an amine group, a hydroxyl group or the like. Examples of the benzotriazole derivative include 4-carboxybenzotriazole and a salt thereof, 7-carboxybenzotriazole and a salt thereof, benzotriazole butyl ester, 1-hydroxymethylbenzotriazole or 1-hydroxyl group. Benzotriazole and the like.

The amount of the corrosion inhibitor added is preferably 1% by mass or less, and preferably 0.001% by mass or more and 0.1% by mass or less based on the total mass of the chemical mechanical polishing composition.

1.7. Use

As described above, the chemical mechanical polishing composition according to the present embodiment can adjust the balance of the oxidizing power and the like of the chemical mechanical polishing composition by containing the component (A), and the corrosion-inhibiting effect of the surface to be treated is drastically improved. Therefore, the chemical mechanical polishing composition according to the present embodiment is suitable as a polishing composition for at least one type of substrate selected from the group consisting of tungsten and a tungsten metal. For example, in the manufacturing step of the semiconductor device, it is suitable as a substrate to be processed such as a semiconductor wafer for polishing a circuit layer containing a metal such as tungsten, and particularly an insulating film such as a tungsten film or a ruthenium oxide film of the object to be processed. The abrasive material of the treated surface coexisted, and the polishing rate can be maintained to suppress the corrosion of the surface of the tungsten film.

1.8. Modulation method of chemical mechanical polishing composition

The chemical mechanical polishing composition according to the present embodiment can be prepared by dissolving or dispersing the above components in the (B) dispersion medium containing water. The method of dissolving or dispersing is not particularly limited, and any method can be applied as long as it can be uniformly dissolved or dispersed. Further, the mixing order or mixing method of the above respective components is not particularly limited.

Further, the chemical mechanical polishing composition according to the present embodiment can be prepared into a concentrated raw liquid, and can be used by being diluted with a water-containing (B) dispersion medium at the time of use.

2. Chemical mechanical polishing method

The chemical mechanical polishing method according to the present embodiment is characterized in that the object to be processed which comprises a circuit layer containing a metal such as tungsten is polished by using the chemical mechanical polishing aqueous dispersion according to the present invention. Hereinafter, a specific example of the chemical mechanical polishing method associated with the present embodiment will be described in detail using the drawings.

2.1. Object to be processed

Fig. 1 is a schematic cross-sectional view showing a suitable object to be processed when the chemical mechanical polishing method according to the embodiment is used. The object to be processed 100 can be formed by the following steps (1) to (4).

(1) First, the substrate 10 is prepared. A functional device such as a transistor (not shown) may be formed on the ruthenium substrate 10.

(2) Next, the tantalum oxide film 12 is formed on the tantalum substrate 10 by a CVD method or a thermal oxidation method.

(3) Next, the tantalum oxide film 12 is patterned. With this as a mask, the circuit recess 20 is formed in the yttrium oxide film 12 by, for example, an etching method.

(4) Next, when the tungsten film 14 is deposited by the CVD method to fill the recess 20 for the circuit, the object to be processed 100 can be obtained.

2.2. Grinding steps

The tungsten film 14 deposited on the tantalum oxide film 12 of the object to be processed 100 is polished and removed by using the chemical mechanical polishing composition described above, and then a barrier metal film such as a tungsten plug or titanium and an insulating film are polished. According to this embodiment By using the above chemical mechanical polishing composition, the chemical mechanical polishing method can polish the surface to be treated in which the insulating film of the tungsten film and the yttrium oxide film coexists, and the polishing speed can be reduced, and the surface of the tungsten film can be reduced. corrosion.

2.3. Chemical mechanical polishing device

For the above grinding step, for example, the chemical mechanical polishing apparatus 200 shown in Fig. 2 can be used. FIG. 2 shows a squint pattern view of the chemical mechanical polishing apparatus 200. In the polishing step, the slurry (chemical mechanical polishing composition) 44 is supplied from the slurry supply nozzle 42 and the turntable 48 to which the polishing cloth 46 is attached is rotated while being held against the carrier head 52 holding the semiconductor substrate 50. get on. Further, the water supply nozzle 54 and the dresser 56 are collectively shown in FIG.

The pressing pressure of the carrier head 52 can be selected in the range of 10 to 1,000 hPa, preferably 30 to 500 hPa. Further, the rotational speed of the turntable 48 and the carrier head 52 can be appropriately selected within the range of 10 to 400 rpm, preferably 30 to 150 rpm. The flow rate of the slurry (chemical mechanical polishing composition) 44 supplied from the slurry supply nozzle 42 can be selected in the range of 10 to 1,000 mL/min, preferably 50 to 400 mL/min.

For example, "EPO-112" and "EPO-222", manufactured by Lapmaster SFT Co., Ltd., model "LGP-510", "LGP-552"; Applied Materials, Inc. System, model "Mirra", "Reflexion", etc.

3. Example

The invention is illustrated by the following examples, but the invention is not limited at all by these examples. The "parts" and "%" in the examples and comparative examples are the quality standards unless otherwise specified.

3.1. Modulation of chemical mechanical polishing components <Example 1>

The colloidal ceria aqueous dispersion PL-3 (Fussan Chemical Industry Co., Ltd.) as (C) abrasive grains is converted to an amount equivalent to 1.5% by mass based on the total mass of the composition for chemical mechanical polishing. The product was added to a polyethylene container, and the amount of the final total constituent component was calculated to be 100% by mass to add ion-exchanged water, and the amount of the final pH was adjusted to 2.5, and nitric acid as a pH adjuster was added. Next, N-lauroyl-N'-carboxymethyl-N'-hydroxyethylethylenediamine sodium (manufactured by Sanyo Chemical Industry Co., Ltd., trade name: LEBON 101-H) was added to 0.030% by mass of citric acid. 112 ppm, 25% by mass of hydrogen peroxide was added to a 35 mass% aqueous hydrogen peroxide solution, and the mixture was stirred for 15 minutes to obtain a chemical mechanical polishing composition of Example 1. The pH of the obtained chemical mechanical polishing composition was 2.5.

<Examples 2 to 14 and Comparative Examples 1 to 10>

A chemical mechanical polishing composition was prepared in the same manner as in Example 1 except that the composition was set as described in Tables 1 and 2. Further, among Examples 2 to 14 and Comparative Examples 2 to 10, as (C) abrasive grains, PL-3C has a particle size and a cationically modified colloidal cerium oxide aqueous dispersion (manufactured by Fuso Chemical Industry Co., Ltd.) having the same particle diameter as the colloidal cerium oxide aqueous dispersion PL-3. In addition, sodium lauryl alkanoate is manufactured by Taiguang Grease Chemical Industry Co., Ltd., trade name Taipol Soft LAP10, and laurylamine dipropionic acid is manufactured by Taiguang Grease Chemical Industry Co., Ltd., trade name Taipol Soft LAP- 30.

3.2. Evaluation method 3.2.1. Evaluation of etch rate

The tungsten-cut wafer (3 × 3 cm) was heated at 45 ° C, immersed in the obtained chemical mechanical polishing composition for 10 minutes, washed with running water for 10 seconds, and dried to measure the thickness variation of the wafer. The thickness change was divided by 10 to calculate the etching rate of tungsten for the chemical mechanical polishing composition. The evaluation criteria for the etching test are as follows.

◎: 0 nm/min or more, less than 2 nm/min

○: 2 nm/min or more, less than 5 nm/min

△: 5 nm/min or more, less than 10 nm/min

×: 10 nm/min or more

3.2.2. Evaluation of grinding speed

The grinding device is made of Lapmaster SFT, model "LM-15C", and the polishing pad is made of Rodel Nitta Co., Ltd., "IC1000/K-Groove", the platform speed is 90 rpm, the grinding head speed is 90 rpm, and the grinding head pressing pressure is 3 psi. , chemical mechanical grinding water system The dispersion supply rate was 100 mL/min, and the surface of the tungsten wafer test piece of the object to be polished was subjected to chemical mechanical polishing (CMP) for 1 minute under the polishing conditions. Next, using a metal film thickness meter "RG-5" manufactured by NPS Co., Ltd., a film thickness of a tungsten wafer test piece cut into 3 × 3 cm as a workpiece to be polished was measured in advance, and chemical mechanical polishing treatment was performed for 1 minute. . The film thickness was measured in the same manner for the polished test piece, and the difference in film thickness before and after the polishing, that is, the film thickness which was reduced by the chemical mechanical polishing treatment, was calculated. The polishing rate was calculated from the reduced film thickness and the polishing time. The evaluation criteria of the grinding speed are as follows.

◎: 200nm/min or more

○: 100 nm/min or more and less than 200 nm/min

△: 10 nm/min or more and less than 100 nm/min

×: less than 10 nm/min

3.2.3. Assessment of corrosion

A tungsten-cut wafer (1 × 1 cm) was immersed in the obtained composition for chemical mechanical polishing for 1 hour, washed with running water for 10 seconds, dried, and then observed for corrosion on the surface by a scanning electron microscope. The evaluation criteria for corrosion are as follows.

○: No change in surface shape due to corrosion was observed as compared with before immersion

×: Partial or total corrosion compared to before impregnation

3.2.4. Evaluation of preservation stability

The obtained chemical mechanical polishing composition was concentrated twice, in the initial stage The particle size was measured by a dynamic light scattering type particle size distribution measuring apparatus after heating at 60 ° C for 2 weeks, and the presence or absence of sedimentation of the abrasive grains was visually confirmed. The evaluation criteria for preservation stability are as follows.

○: No change in particle diameter was observed as compared with the initial particle diameter

△: A change in the particle diameter was observed as compared with the initial particle diameter, but the abrasive grain sedimentation was not observed visually.

×: A change in the particle diameter was observed as compared with the initial particle diameter, and the abrasive grain sedimentation was visually observed.

3.3. Evaluation results

The composition and evaluation results of the chemical mechanical polishing compositions obtained in Examples 1 to 14 are disclosed in Table 1 below, and the compositions and evaluation results of the chemical mechanical polishing compositions obtained in Comparative Examples 1 to 10 are disclosed. Table 2 below.

As is apparent from the above Tables 1 and 2, in the case of the chemical mechanical polishing composition according to the present invention disclosed in Examples 1 to 14, the tungsten film of the object to be processed can be polished and compared with Comparative Examples 1 to 10. The surface to be treated in which the insulating film such as the ruthenium oxide film coexists, and the polishing rate is not lowered, and the corrosion of the surface of the tungsten film is reduced. In particular, in the case of Examples 2 to 14 in which the (E) metal salt was added, it was possible to maintain a high polishing rate and reduce corrosion on the surface of the tungsten film as compared with Examples 1 and 2. Further, in the case of Comparative Example 8, since the pH was higher than 3.5, Fe ^{2+ was} precipitated as iron hydroxide, and thus it was impossible to evaluate. Further, in the case of Comparative Example 5, which has a structure similar to the component (A), but has a larger number of carbon atoms bonded to a nitrogen atom than the component (A), Although a high polishing rate is obtained, it is a 4-grade ammonium compound, so storage stability cannot be obtained.

The present invention is not limited to the above embodiments, and various modifications can be made. The present invention includes substantially the same configurations as those described in the embodiments (for example, configurations having the same functions, methods, and results, or configurations having the same objects and effects). Further, the present invention also includes a configuration in which a portion that is not essential in the configuration described in the above embodiment is replaced with another configuration. Further, the present invention also includes a configuration that can achieve the same effects as the configuration described in the above embodiment or a configuration that achieves the same object. The present invention also includes a configuration in which the configuration described in the above embodiment is added to a well-known technique.

Claims (6)

A chemical mechanical polishing composition comprising: (A) a compound represented by the following general formula (1) or a salt thereof, (B) a dispersion medium containing water, (C) abrasive grains, and (D) an oxidizing agent , (In the above formula (1), R1 is a group having a substituted or unsubstituted alkyl group having 8 or more carbon atoms, R2 is a hydrogen atom, an organic group having 1 to 3 carbon atoms having a hydroxyl group or a carboxyl group, and R3 is a carbon number. 1~3 of the alkyl group). The chemical mechanical polishing composition according to claim 1, further comprising (E) at least one metal ion selected from the group consisting of Fe ²⁺ , Fe ³⁺ , and Cu ²⁺ . The chemical mechanical polishing composition according to claim 1 or 2, wherein the ratio (A)/(D) of the component (A) to the component (D) is 0.005 to 0.1. The chemical mechanical polishing composition according to any one of claims 1 to 3, wherein the pH is from 1.5 to 3.5. The chemical mechanical polishing composition according to any one of claims 1 to 4, wherein the composition for polishing at least one of the group consisting of tungsten and a tungsten metal is used for polishing. A chemical mechanical polishing method for polishing a target object including a metal-containing circuit layer by using the chemical mechanical polishing composition according to any one of claims 1 to 5.