JP2004235619A - Cleaning liquid for semiconductor substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning liquid which is superior in removing a particle foreign matter and an ionic foreign matter on a semiconductor substrate, after a CMP (chemical mechanical polishing) process. <P>SOLUTION: The cleaning liquid for the semiconductor substrate is characterised by containing at least one kind among nonionic surfactants shown by formula (1), CH<SB>3</SB>-(CH<SB>2</SB>)<SB>I</SB>-O-(C<SB>m</SB>H<SB>2m</SB>O)<SB>n</SB>-X and, by formula (2), CH<SB>3</SB>-(CH<SB>2</SB>)<SB>a</SB>-O-(C<SB>b</SB>H<SB>2b</SB>O)<SB>d</SB>-(C<SB>x</SB>H<SB>2x</SB>O)<SB>y</SB>-X, a chelating agent, and a chelate promoter. Each of I,m, and n in the formula independently represents a positive number, and X represents a hydrogen atom or a hydrocarbon group. Each of a,b,d,x, and y in the formula independently represents a positive number, and b and x are different from each other. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a cleaning liquid for a semiconductor substrate.

In recent years, Cu wiring has been introduced in semiconductor devices, and a chemical mechanical polishing process (CMP process) has been adopted for forming the Cu wiring.
In the CMP process, after forming grooves and connection holes in a low-permittivity insulating film such as carbon-containing SiO ₂ (SiOC) which has been planarized in advance, Cu is deposited by plating or the like to form the grooves and connection holes. By embedding and polishing with a slurry containing special abrasive grains and additives, Cu other than grooves and connection holes is removed to flatten the surface and form wiring and connection holes.
On the semiconductor substrate after the CMP process, a large amount of fine particulate foreign substances such as abrasive grains and polishing debris in the polishing slurry and ionic foreign substances such as metal impurities are attached in large amounts. There is a demand for the development of a cleaning solution that can simultaneously remove the water.
Examples of such a washing liquid include a nonionic surfactant having a phenylene group such as polyoxyethylene nonylphenyl ether, a compound that forms a complex with a metal such as aminoacetic acid or quinaldic acid, and an alkali component. A cleaning liquid is known (see Patent Document 1).
However, when a hydrophobic low dielectric constant insulating film such as SiOC is used as the cleaning liquid, wettability with the insulating film is poor, and removal of particulate foreign matter and ionic foreign matter on the semiconductor substrate after the CMP process is performed. There was a problem that was difficult.

JP-A-2002-270566

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning liquid that is excellent in removing particulate foreign matter and ionic foreign matter on a semiconductor substrate after a CMP process.

  The present inventors have conducted intensive studies to find a cleaning solution that can solve the above-mentioned problems, and as a result, among nonionic surfactants having no phenylene group represented by the following formulas (1) and (2): A cleaning solution containing at least one kind, a chelating agent, and a chelating accelerator has been found to be excellent in removing particulate foreign matter and ionic foreign matter on a semiconductor substrate, and has completed the present invention. .

That is, the present invention relates to the general formula (1)
_{CH 3 - (CH 2) l} -O- (C m H 2m O) n -X (1)
(Where l, m and n in the formula each independently represent a positive number, and X represents a hydrogen atom or a hydrocarbon group)
And / or general formula (2),
_{CH 3 - (CH 2) a} -O- (C b H 2b O) d - (C x H 2x O) y -X (2)
(Where a, b, d, x and y in the formula each independently represent a positive number, b and x are different from each other, and X represents a hydrogen atom or a hydrocarbon group)
And a chelating agent and a chelating accelerator.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the cleaning liquid excellent in the removability of the particulate foreign matter and the ionic foreign matter on the semiconductor substrate after a CMP process.

The surfactant contained in the cleaning solution of the present invention is represented by the general formula (1)
_{CH 3 - (CH 2) l} -O- (C m H 2m O) n -X (1)
(Where l, m and n in the formula each independently represent a positive number, and X represents a hydrogen atom or a hydrocarbon group)
And general formula (2)
_{CH 3 - (CH 2) a} -O- (C b H 2b O) d - (C x H 2x O) y -X (2)
(Where a, b, d, x and y in the formula each independently represent a positive number, b and x are different from each other, and X represents a hydrogen atom or a hydrocarbon group)
The nonionic surfactant shown by these is mentioned.

In the general formula (1) or (2), l and a represent positive numbers, preferably 8 to 18, more preferably 8 to 11, and even more preferably 9 to 11.
When l and a are less than 8 or more than 18, the wettability with the insulating film having a low dielectric constant is deteriorated, and the removability of particulate foreign matter tends to decrease. Since the action is enhanced, the dissolution in an aqueous solution tends to be difficult.
X is a hydrogen atom or a hydrocarbon group, and examples of the hydrocarbon group include a methyl group and an ethyl group.

In the general formula (1), m represents a positive number, is 2 or 3, and is more preferably 2.
n represents a positive number, preferably from 4 to 20, more preferably from 5 to 10.
If n is less than 4, the solubility in an aqueous solution tends to deteriorate, and if n exceeds 20, the wettability with an insulating film having a low dielectric constant tends to deteriorate.

In the general formula (2), b and d represent positive numbers, and b is usually 2.
D is usually 1 to 20, preferably 1 to 10. If d exceeds 20, wettability with an insulating film having a low dielectric constant tends to be poor.

In the general formula (2), x and y represent positive numbers, and x is usually 3 to 10, preferably 3 to 5, and more preferably 3. If x exceeds 10, the solubility in water tends to be poor.
Y is usually 1 to 10, preferably 1 to 5. If y exceeds 10, wettability with an insulating film having a low dielectric constant tends to be poor.

  The nonionic surfactant represented by the general formula (2) is a form in which two kinds of alkylene oxides are polymerized, and the polymerization form is not particularly limited, and there are various forms such as random copolymerization and block copolymerization. sell.

In the nonionic surfactants represented by the general formulas (1) and (2), the starting material of the lipophilic group is a primary alcohol, and those in which 1 and a are 9 to 11 are preferable. Even when the total number of carbon atoms in the lipophilic group is 10 to 12, a nonionic surfactant starting from a secondary alcohol, for example, the following general formula (4) or (5)
General formula (4)
_{(CH 3 - (CH 2)} 4) 2 CH-O- (C m H 2m O) n -X (4)
General formula (5)
_{(CH 3 - (CH 2)} 4) 2 CH-O- (C b H 2b O) d - (C x H 2x O) y -X
(5)
(M, n, b, d, x, y, and X have the same meaning as described above.)
The nonionic surfactant represented by, even if the wettability with a low dielectric constant insulating film is improved, the surfactant remains on the surface, and the removal of particulate foreign matter is insufficient, and is satisfactory. It is difficult to obtain good cleaning performance.

Examples of the nonionic surfactant represented by the general formula (1) or (2) include polyoxyethylene decyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, and polyoxyethylene. Examples thereof include polyoxypropylene lauryl ether, polyoxyethylene polyoxypropylene stearyl ether, and polyoxyethylene polyoxypropylene decyl ether.
Of these, polyoxyethylene decyl ether, polyoxyethylene lauryl ether, polyoxyethylene polyoxypropylene decyl ether, and polyoxyethylene polyoxypropylene lauryl ether are preferably used.

The concentration of the nonionic surfactant (sum of the general formulas (1) and (2)) in the cleaning solution is preferably 0.0001 to 1% by weight, and more preferably 0.001 to 1% by weight. More preferred.
If the amount is less than 0.0001% by weight, the wettability with the insulating film having a low dielectric constant tends to be deteriorated. If the amount exceeds 1% by weight, the foaming property of the cleaning liquid is increased, and the workability at the time of cleaning tends to be deteriorated. is there.

The chelating agent is not particularly limited as long as it can remove a metal.For example, polyaminocarboxylic acids, polycarboxylic acids, compounds having a phosphonic acid group, oxycarboxylic acids, phenols, heterocyclic compounds, and tropolone At least one selected from the group consisting of Here, the term “class” generally includes a salt or a derivative of the compound.
As polyaminocarboxylic acids, for example, ethylenediaminetetraacetic acid (EDTA), trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), N- (2-hydroxyethyl) Ethylenediamine-N, N ', N'-triacetic acid (EDTA-OH) and the like.
Among them, ethylenediaminetetraacetic acid (EDTA) is preferably used.

Examples of the polycarboxylic acids include oxalic acid, malonic acid, succinic acid, glutanic acid, methylmalonic acid, 2-carboxybutyric acid, and ammonium salts thereof.
Among them, oxalic acid and ammonium oxalate are preferably used.

Examples of the compounds having a phosphonic acid group include ethylenediaminetetramethylenephosphonic acid, ethylenediaminedimethylenephosphonic acid, nitrilotrismethylenephosphonic acid, 1-hydroxyethylidenediphosphonic acid, and the like.
Among them, 1-hydroxyethylidene diphosphonic acid is preferably used.

Examples of the oxycarboxylic acids include gluconic acid, tartaric acid, citric acid and the like.
Among them, citric acid and ammonium citrate are preferably used.

Examples of phenols include phenol, cresol, ethylphenol, t-butylphenol, methoxyphenol, catechol, resorcinol, hydroquinone, 4-methylpyrocatechol, 2-methylhydroquinone, pyrogallol, 3,4-dihydroxybenzoic acid, and gallic acid , 2,3,4-trihydroxybenzoic acid, 2,4-dihydroxy-6-methylbenzoic acid, ethylenediamine diorthohydroxyphenylacetic acid [EDDHA], N, N-bis (2-hydroxybenzyl) ethylenediamine-N, N -Acetic acid [HBED], ethylenediaminedihydroxymethylphenylacetic acid [EDDHMA] and the like.
Among them, catechol and ethylenediamine diorthohydroxyphenylacetic acid [EDDHA] are preferably used.

Examples of the heterocyclic compounds include 8-quinolinol, 2-methyl-8-quinolinol, quinolinediol, 1- (2-pyridylazo) -2-naphthol, 2-amino-4,6,7-pteridinetriol, 5,7,3'4'-tetrahydroxyflavone [luteolin], 3,3'-bis [N, N-bis (carboxymethyl) aminomethyl] fluorescein [calcein], 2,3-hydroxypyridine and the like. .
Among them, 8-quinolinol is preferably used.

Examples of the tropolone include tropolone, 6-isopropyltropolone, and the like.
Among them, tropolone is preferably used.

The concentration of the chelating agent in the cleaning liquid is preferably 0.00001 to 10% by weight, more preferably 0.0001 to 1% by weight.
If it is less than 0.00001% by weight, the metal removal performance as a chelating agent tends to decrease, and if it exceeds 10% by weight, the solubility in a cleaning solution tends to decrease.

The chelation accelerator is added to more effectively chelate metal impurities adhering to the semiconductor substrate.
Examples of the chelating accelerator include general acidic compounds and alkaline compounds, and salts thereof. Examples of the acidic compound include a fluoride or a salt thereof, and examples of the alkaline compound include a hydroxide.

Here, examples of the fluoride or a salt thereof include hydrofluoric acid, potassium fluoride, sodium fluoride, ammonium fluoride and the like.
Among them, ammonium fluoride is preferably used.

Here, as the hydroxide, for example, a compound having a hydroxyl group can be mentioned, and specific examples thereof include inorganic compounds such as sodium hydroxide, potassium hydroxide and ammonium hydroxide, and quaternary ammoniums such as tetramethylammonium hydroxide and choline. Hydroxide, monoethanolamine, diethanolamine, triethanolamine, 2-methylaminoethanol, 2-ethylaminoethanol, N-methyldiethanolamine, dimethylaminoethanol, 2- (2-aminoethoxy) ethanol, 1-amino- Alkanolamines such as 2-propanol, monopropanolamine, dibutanolamine and the like can be mentioned.
Among them, compounds containing no metal such as ammonium hydroxide, tetramethylammonium hydroxide, and choline are preferably used from the viewpoint of not contaminating the surface of the semiconductor substrate (silicon wafer) with metal.

  The chelate accelerator preferably contains a hydroxide and a fluoride or a salt thereof. Those containing only a hydroxide or only a fluoride or a salt thereof tend not to exert their effects sufficiently, and a chelating accelerator containing both of them improves the metal removal property by the chelating agent. It is preferable because it can be performed.

The concentration of fluoride or a salt thereof in the washing solution is preferably 0.0001 to 40% by weight, and more preferably 0.01 to 5% by weight.
If the amount is less than 0.0001% by weight, the metal removability tends to decrease. If the amount exceeds 40% by weight, the quality of the underlying low dielectric constant insulating film is degraded despite the fact that the metal removability is not improved. Tend to.

  The concentration of the hydroxide in the cleaning liquid is preferably 0.0001 to 30% by weight, more preferably 0.001 to 1% by weight. If the amount is less than 0.0001% by weight, the metal removal property tends to decrease. If the amount exceeds 30% by weight, the quality of the underlying low dielectric constant insulating film tends to deteriorate.

Regarding the relationship between the concentration of the hydroxide and the fluoride or the salt thereof, the concentration of the hydroxide is preferably equal to or less than the concentration of the fluoride.
If the hydroxide concentration is higher than the fluoride concentration, the quality of the underlying low dielectric constant insulating film tends to deteriorate.

The cleaning liquid of the present invention aims at removing particulate foreign matter and ionic foreign matter on a semiconductor substrate (wafer) on which a low dielectric constant insulating film is exposed in a process of manufacturing a semiconductor device, but also exposes a Cu wiring. In some cases, the cleaning solution of the present invention preferably further contains a metal anticorrosive.
The metal anticorrosive preferably contains an organic compound having at least one of a nitrogen atom, an oxygen atom, a phosphorus atom, and a sulfur atom in a molecule, and particularly a compound having at least one azole group in a molecule. More specifically, it is more preferable to contain benzotriazole, toltriazole, 4-methylimidazole, 5-hydroxymethyl-4-methylimidazole, 3-aminotriazole and the like.
Further, the metal anticorrosive has at least one mercapto group, the carbon atom to which the mercapto group is bonded and the carbon atom to which the hydroxyl group is bonded are adjacent to each other, and has 2 or more carbon atoms. More preferably, the composition contains an aliphatic alcohol compound.
Examples of the metal anticorrosive include thioglycerol and thioglycol.

  The pH of the cleaning solution of the present invention is preferably from 7 to 12, and more preferably from 7 to less than 9. When the pH is less than 7 (acidic), not only does the removability of the fine particles tend to decrease, but also corrosion tends to occur between Cu and the barrier metal due to the battery effect during cleaning.

The cleaning solution of the present invention is excellent in removing particulate foreign matter and ionic foreign matter on a semiconductor substrate (wafer) on which an insulating film having a low dielectric constant is exposed.
Examples of the low dielectric constant insulating film include inorganic materials such as FSG (F-containing SiO ₂ ), SiOC (carbon-containing SiO ₂ ), and SiON (N-containing SiO ₂ ), MSQ (methylsilsesquioxane), and HSQ. (Hydrogensilsesquioxane), polyorganosiloxanes such as MHSQ (methylated hydrogensilsesquioxane), aromatics such as PAE (polyarylether) and BCB (divinylsiloxane-bis-benzocyclobutene) , Silk, Porous Silk and the like.
Here, the low dielectric constant insulating film means a film having a relative dielectric constant of 3.0 or less.
The cleaning liquid of the present invention can be used irrespective of the type of these low dielectric constant insulating films and the method of forming the same, but is particularly effective for insulating films such as SiOC, MSQ, PAE (polyaryl ether) and the like. Therefore, it is preferable to use these insulating films.

The cleaning solution of the present invention may be used alone, or may be used by mixing with other chemical solutions as long as the object of the present invention is not impaired.
Examples of other chemicals include various anionic, cationic, and nonionic surfactants, dispersants, metal anticorrosives, and aqueous hydrogen peroxide.
Further, an antifoaming agent may be added to suppress the air bubbles caused by the surfactant.
Examples of the antifoaming agent include silicone, polyether, special nonionic, and fatty acid ester antifoaming agents, methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-1-propanol, and acetone. And water-soluble organic compounds such as methyl ethyl ketone.

As a method for cleaning a semiconductor substrate (such as a silicon wafer) using the cleaning liquid of the present invention, a immersion cleaning method in which a wafer is directly immersed in the cleaning liquid, a method using ultrasonic irradiation in combination with the immersion cleaning method, and a method in which the cleaning liquid is applied to the substrate surface Spray cleaning by spraying, a brush scrub cleaning method of cleaning with a brush while spraying a cleaning liquid, and a method of using ultrasonic irradiation in combination therewith, and the like can be mentioned.
Further, the cleaning liquid may be heated at the time of cleaning.

Next, as a cleaning example using the cleaning liquid of the present invention, a case of cleaning a wafer on which an insulating film having a low dielectric constant is exposed in the manufacture of a semiconductor device will be described.
First, as shown in FIG. 1A, after a silicon oxide film 1 and a silicon nitride film 2 are formed on a semiconductor substrate (not shown) on which elements such as transistors are formed, a low dielectric constant insulating film 3, a low dielectric constant A cap layer film (eg, SiO ₂ film) 4 for protecting the insulating film is formed. Then, after forming a groove using a known lithography process, a barrier metal film 5 and a copper film 6 are formed as shown in FIG. 1B, and the copper film and the barrier metal are formed using a known CMP process. A copper wiring is formed by polishing the film. Thereafter, as shown in FIG. 1 (c), polishing debris adhered to the surface by polishing, slurry components in the abrasive, metal impurities, and the like are removed. However, if the CMP process can uniformly polish the wafer surface, the low dielectric constant insulating film is not exposed on the surface. If the polishing is not uniform, as shown in FIG. May be removed by polishing to expose the low dielectric constant insulating film. In such a case, it is difficult to clean the exposed low dielectric constant insulating film with the conventional cleaning liquid, but the cleaning liquid of the present invention can be applied.
In the case of a wiring having a wide width, dishing is liable to occur. If the cap layer 7 is formed on the copper wiring after cleaning and the low dielectric constant insulating film 8 is further formed on the copper wiring, as shown in FIG. The concave portion at the center of the Cu wiring is also reflected in the upper low-dielectric-constant insulating film 8 and is not flat. As described above, if the low dielectric constant insulating film 8 is concave, there is a possibility that a problem may occur that the focus is not obtained in the next step of lithography. Therefore, this low dielectric constant insulating film is planarized by a CMP process. There is a need to. The cleaning liquid of the present invention can also be applied to a case where foreign substances on the surface after polishing such a low dielectric constant insulating film by a CMP process are cleaned.

  The cleaning solution of the present invention is excellent in removing particulate foreign matter and ionic foreign matter on a semiconductor substrate after a CMP process, and particularly for cleaning the surface where the low dielectric constant insulating film showing hydrophobicity is exposed. Can be suitably applied.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to Examples.

Example 1
Cleaning liquid 1 or cleaning liquid 2 was prepared according to the composition shown in Table 1. Using these cleaning liquids 1 and 2, a wafer was prepared in which a SiOC film, which is a kind of a low dielectric constant insulating film contaminated with fine particles and metal impurities, was previously formed on the surface, and was cleaned using a brush cleaning device. Table 1 also shows the number of residual fine particles and the concentration of residual metal impurities in this case.
The fine particles contaminated on the SiOC film wafer before cleaning were immersed in CuCMP slurry to contaminate abrasive particles in the slurry on the film surface. The number of contaminated particles before washing is 3000 / sheet. Further, the metal impurities caused metal contamination on the exposed SiOC film by actually polishing the Cu film by CuCMP, and the metal contamination amount before cleaning was 5 × 10 ¹² atoms / cm ² of Cu.

＊１ ｌが１１、ｍが２、ｎが８、Ｘが水素原子である一般式（１）で表される非イオン性界面活性剤
＊２
ａが１１、ｂが２、ｄが１０、ｘが３、ｙ１が１、Ｘが水素原子である一般式２で表される界面活性剤

* 1 Nonionic surfactant represented by the general formula (1) in which 1 is 11, m is 2, n is 8, and X is a hydrogen atom. * 2
a is 11, a is 2, b is 2, d is 10, x is 3, y1 is 1, and X is a hydrogen atom.

  As shown in Table 1, by cleaning with the cleaning solution of the present invention, fine particles and Cu impurities on the SiOC film were removed to a level necessary for manufacturing a semiconductor device.

Example 2, Comparative Examples 1 and 2
Using an SiOC film contaminated with fine particles by the same method as in Example 1 and a brush cleaning machine, cleaning was performed with a cleaning liquid shown in Table 2 (the type of surfactant in the cleaning liquid was changed), and the fine particle removal properties were compared. Table 2 shows the results. Further, the wettability of each cleaning liquid to the SiOC film was compared by measuring the contact angle between the cleaning liquid and the SiOC film.

＊１ ｌが１１、ｍが２、ｎが８、Ｘが水素原子である一般式（１）で表される非イオン性界面活性剤
＊３ 日本触媒社製 第２級高級アルコールエトキシレート
親油基炭素数１２の第２級アルコールを用い、ｍが２、ｎが７、Ｘが水素原子である一般式（４）で対応する非イオン性界面活性剤

* 1 Nonionic surfactant represented by the general formula (1) in which 1 is 11, m is 2, n is 8, and X is a hydrogen atom. * 3 Nippon Shokubai's secondary higher alcohol ethoxylate. Nonionic surfactant corresponding to the general formula (4), wherein a secondary alcohol having 12 carbon atoms is used, m is 2, n is 7, and X is a hydrogen atom.

  As shown in Table 2, in Comparative Example 2 containing no surfactant, the wettability with the SiOC film was poor and the fine particles were hardly removed. On the other hand, although the wettability can be improved by adding a surfactant, the surfactant of Comparative Example 1 has poor fine particle removal properties and is at an insufficient level for semiconductor device production.

Example 3, Comparative Examples 3 and 4
A cleaning solution having a composition shown in Table 3 was prepared, and a silicon oxide film wafer was immersed therein for 2 minutes. After that, the amount of metal remaining on the wafer surface was analyzed. The silicon oxide film wafer before cleaning was rotated on a spin coater rotating at 200 rpm, and 40 ml of ultrapure water containing 1 ppm of Fe and Al was dropped on the surface to cause metal contamination on the silicon oxide film surface. Was used. Metal deposition amount before washing Fe is ^{490 × 10 10 atom / cm 2} , Al was ^{340 × 10 10 atom / cm 2} .

＊１ ｌが１１、ｍが２、ｎが８、Ｘが水素原子である一般式（１）で表される非イオン性界面活性剤

* 1 Nonionic surfactant represented by the general formula (1) in which 1 is 11, m is 2, n is 8, and X is a hydrogen atom.

  As a result of Table 3, the cleaning liquid 1 showed good metal removal performance, but in Comparative Example 4 containing no chelating agent and Comparative Example 3 containing no chelating accelerator, sufficient metal removal properties could not be obtained. Was.

Examples 4-5, Comparative Examples 5-6
The contact angles with the low dielectric constant films in the cleaning solutions 1, 2, 7, or 8 in which various surfactants adjusted to the compositions shown in Table 4 were dissolved were measured. Table 4 shows the results. In this case, the solubility of the surfactant was visually evaluated based on the degree of turbidity of the liquid. Note that a PAE film was used as the low dielectric constant film, and the surfactant concentration in the cleaning solution was 0.1%.

＊１ ｌが１１、ｍが２、ｎが８、Ｘが水素原子である一般式（１）で示される非イオン性界面活性剤
＊４ ａが１１、ｂが２、ｄが１０、ｙが１、Ｘが水素原子である一般式（２）で表される非イオン界面活性剤。
＊５青木油脂社製 ポリオキシエチレンノニルフェニルエーテル
一般式（１）においてＣＨ_３−（ＣＨ_２）_ｌの親油基がノニルフェニル基に相当、ｍが２、ｎが２０、Ｘが水素原子である界面活性剤。
＊６青木油脂社製 ポリオキシエチレン２−エチルヘキシルエーテル
一般式（１）においてＣＨ_３−（ＣＨ_２）_ｌの親油基が２−エチルヘキシル基に相当、ｍが２、ｎが６、Ｘが水素原子である界面活性剤。

* 1 Nonionic surfactant represented by the general formula (1) in which 1 is 11, m is 2, n is 8, and X is a hydrogen atom. * 4 a is 11, b is 2, d is 10, and y is 1. A nonionic surfactant represented by the general formula (2), wherein X is a hydrogen atom.
* 5 Polyoxyethylene nonylphenyl ether manufactured by Aoki Yushi Co., Ltd. In the general formula (1), the lipophilic group of CH ₃ — (CH ₂ ) ₁ corresponds to a nonylphenyl group, m is 2, n is 20, and X is a hydrogen atom. Some surfactants.
* 6 Polyoxyethylene 2-ethylhexyl ether manufactured by Aoki Yushi Co., Ltd. In formula (1), the lipophilic group of CH ₃ — (CH ₂ ) ₁ corresponds to a 2-ethylhexyl group, m is 2, n is 6, and X is hydrogen. A surfactant that is an atom.

  As shown in Table 4, the surfactants represented by the general formulas (1) and (2) have good wettability with the low dielectric constant film. On the other hand, even when a surfactant similar to the general formula (1) has a different lipophilic group structure, the contact angle with the low dielectric constant film is high and the wettability is poor. A phenomenon of cloudiness without dissolving in the washing solution was observed.

It is a process sectional view showing an example of a manufacturing process of a semiconductor device using a cleaning fluid of the present invention. A process cross-sectional view is shown subsequent to FIG.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Silicon oxide film 2 Silicon nitride film 3 Low dielectric constant insulating film 4 Cap layer film 5 Barrier metal film 6 Copper film 7 Cap layer film 8 Low dielectric constant insulating film

Claims (19)

General formula (1)
_{CH 3 - (CH 2) l} -O- (C m H 2m O) n -X (1)
(Where l, m and n in the formula each independently represent a positive number, and X represents a hydrogen atom or a hydrocarbon group)
A cleaning liquid for a semiconductor substrate, comprising: a nonionic surfactant represented by the formula:, a chelating agent, and a chelating accelerator.   The cleaning solution according to claim 1, wherein 1 is 8 to 11.   3. The cleaning solution according to claim 1, wherein m is 2 and n is 5 to 10. Further, the general formula (2),
_{CH 3 - (CH 2) a} -O- (C b H 2b O) d - (C x H 2x O) y -X (2)
(In the formula, a, b, d, x, and y each independently represent a positive number, and b and x are different from each other. X represents a hydrogen atom or a hydrocarbon group.)
The cleaning liquid for a semiconductor substrate according to any one of claims 1 to 3, further comprising a nonionic surfactant represented by the formula:   A cleaning liquid for a semiconductor substrate, comprising a nonionic surfactant represented by the general formula (2), a chelating agent, and a chelating accelerator.   6. The semiconductor substrate cleaning liquid according to claim 4, wherein a is 8 to 11.   The cleaning liquid according to any one of claims 4 to 6, wherein b is 2, x is 3 to 5, d is 10 or less, and y is 5 or less.   The chelating agent is at least one selected from the group consisting of polyaminocarboxylic acids, polycarboxylic acids, compounds having a phosphonic acid group, oxycarboxylic acids, phenols, heterocyclic compounds, and tropolones. The cleaning solution according to any one of claims 1 to 7.   The chelating agent is at least one selected from the group consisting of ethylenediaminetetraacetic acid, oxalic acid, ammonium oxalate, 1-hydroxyethylidene diphosphonic acid, citric acid, ammonium citrate, catechol, 8-quinolinol, and tropolone. Item 9. The cleaning solution according to Item 8.   The cleaning liquid according to any one of claims 1 to 9, wherein the chelating accelerator contains a hydroxide and a fluoride or a salt thereof.   The cleaning solution according to claim 10, wherein the hydroxide is a compound containing no metal.   12. The cleaning solution according to claim 10, wherein the hydroxide is at least one selected from the group consisting of ammonium hydroxide, tetramethylammonium hydroxide, and choline.   The cleaning solution according to claim 10, wherein the fluoride or a salt thereof is hydrofluoric acid or ammonium fluoride.   The cleaning solution according to any one of claims 1 to 13, further comprising a metal anticorrosive.   The cleaning solution according to claim 14, wherein the metal anticorrosive is an organic compound having at least one of a nitrogen atom, an oxygen atom, a phosphorus atom, and a sulfur atom in a molecule.   16. The cleaning solution according to claim 14, wherein the metal anticorrosive is a compound having at least one azole group in a molecule.   The metal anticorrosive is an aliphatic alcohol-based compound having at least one mercapto group, wherein a carbon atom to which a mercapto group is bonded and a carbon atom to which a hydroxyl group are adjacent to each other. 15. The cleaning solution according to any one of the above items 15.   The cleaning solution according to any one of claims 1 to 17, which has a pH of 7 or more. A method for manufacturing a semiconductor device, comprising: cleaning a low-dielectric-constant insulating film exposed on a semiconductor substrate by using the cleaning liquid according to claim 1.

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