JP2009071165A - Substrate cleaning liquid for semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide substrate cleaning liquid for semiconductor device, which has superior removal property and re-sticking prevention property against contamination with particles and organic matter sticking on a substrate surface, metal contamination, and composite contamination with organic matter and metal, which provides high-level cleaning without corroding the substrate surface, and has superior cleaning capability, particularly, for a low-k material which is easy to repel chemicals because of hydrophobic property and has inferior particle removal property. <P>SOLUTION: Disclosed is the substrate cleaning liquid for semiconductor device obtained by mixing (A) organic acid, (B) one or more selected from a group of sulfosuccinic acid, alkyl sulfuric acid, alkyl ether sulfuric acid, and salts thereof, and water. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cleaning liquid used for cleaning a substrate surface of a semiconductor, glass, metal, ceramics, resin, magnetic material, superconductor, or the like in which metal contamination or particle contamination is a problem. More specifically, the present invention relates to a cleaning liquid for effectively cleaning a semiconductor device substrate surface in a manufacturing process of a semiconductor device substrate for a semiconductor element or a display device, which requires a highly clean substrate surface.

  The substrate cleaning solution for a semiconductor device of the present invention has a surface of a semiconductor material such as silicon, an insulating material such as silicon nitride, silicon oxide, glass, or a low dielectric constant (Low-k) material, a transition metal or a transition metal compound. In the semiconductor device substrate that is partly or entirely, removes fine particles (particles) attached to the substrate surface, organic contamination, metal contamination, and composite contamination due to organic matter and metal, and also suppresses reattachment and roughens the substrate surface. It is useful as a cleaning liquid that is highly purified without causing corrosion or corrosion.

  In the manufacturing process of semiconductor devices such as microprocessors, logic LSIs, DRAMs, flash memories and CCDs, and flat panel display devices such as TFT liquid crystals, dimensions on the substrate surface of silicon, silicon oxide, glass, etc., from submicron to nanometer order In the manufacturing process, it is extremely important to reduce a small amount of contamination on the surface of the substrate. Among trace contaminations on the substrate surface, especially particle contamination, organic contamination, and metal contamination reduce the electrical characteristics and yield of the device, so it is necessary to reduce them as much as possible before bringing them into the next process. In order to remove such contamination, the substrate surface is generally cleaned with a cleaning liquid.

  In recent years, there has been a demand for further improvement in throughput and production efficiency in semiconductor device manufacturing. For the cleaning of substrates for semiconductor device manufacturing, which are becoming increasingly miniaturized and highly integrated, there are particle contamination and organic contamination on the substrate surface. In addition, there is a demand for a cleaning technique that is excellent not only in the removability of metal contamination but also in the ability to prevent re-adhesion after removal, and can rapidly clean the substrate surface.

  Conventionally, it is known that an alkaline solution is effective as a cleaning liquid used for removing particle contamination of a semiconductor device substrate, and an aqueous ammonia solution is used for cleaning the surface of a semiconductor device substrate such as a semiconductor element or a display device. Alkaline aqueous solutions such as potassium hydroxide aqueous solution and tetramethylammonium hydroxide aqueous solution are used. Further, cleaning (referred to as “SC-1 cleaning” or “APM cleaning”) using a cleaning liquid (referred to as “SC-1 cleaning liquid” or “APM cleaning liquid”) containing ammonia, hydrogen peroxide, and water is also widely used ( W. Kern and DAPuotinen: RCA Review, p.187, June (1970), etc.).

  However, the alkaline cleaning liquid is concerned about etching of the silicon or silicon oxide film on the surface of the substrate, and has a problem that it is difficult to sufficiently remove the combined contamination with organic matter and metal.

In recent years, therefore, there has been proposed an acidic cleaning solution in which a surfactant is added to an acidic solution effective for removing metal contamination on the substrate surface for the purpose of improving particle contamination removal.
For example, Japanese Patent Laid-Open No. 7-216392 discloses cleaning a silicon wafer using a specific surfactant and hydrofluoric acid, and Japanese Patent Laid-Open No. 8-69990 discloses a hydrofluoric acid aqueous solution for cleaning a silicon wafer. It is proposed to add a surfactant and ozone. In JP-A-2001-7071, a cleaning liquid in which an organic acid compound is added to a dispersant and / or a surfactant is used to remove metal impurities and particle contamination adsorbed on a substrate having metal wiring. Proposed.

However, a solution using hydrofluoric acid or a salt thereof has a problem in waste liquid treatment due to the inclusion of fluorine ions in addition to the etching of the coexisting thin film layer. In addition, it is difficult to sufficiently wet the substrate surface with a highly hydrophobic low dielectric constant (Low-k) material in a cleaning solution in which an organic acid compound is added to a surfactant, and the substrate surface is sufficiently decontaminated. It wasn't.
JP 7-216392 A JP-A-8-69990 JP 2001-7071 A W. Kern and DAPuotinen: RCA Review, p.187, June (1970)

Interlayer insulation is used to realize high speed and highly integrated LSI devices by introducing low resistance Cu into the wiring material instead of silicon oxide such as TEOS, which has been used as an interlayer insulation film. A highly hydrophobic low dielectric constant (Low-k) material is planned to be used for the film. However, this material easily repels a chemical solution such as a cleaning solution, and therefore, it is difficult to remove contamination by cleaning.
Even for hydrophobic substrate surfaces such as low dielectric constant (Low-k) materials, cleaning solutions with excellent metal contamination, particle contamination, combined contamination with organic matter and metal, and anti-redeposition property are provided. However, it has been a problem in cleaning semiconductor device substrates.

Accordingly, an object of the present invention is to provide a substrate cleaning solution for a semiconductor device for solving these problems.
Specifically, for semiconductor devices having a semiconductor material such as silicon, an insulating material such as silicon nitride, silicon oxide, glass, or a low dielectric constant (Low-k) material, a transition metal or a transition metal compound over a part of or the entire surface. Efficiently removes contamination of particles and organic matter, metal contamination and combined contamination of organic matter and metal on the substrate surface, suppresses re-adhesion, and does not cause surface roughness or corrosion. An object of the present invention is to provide a substrate cleaning solution for a semiconductor device that can be cleaned easily. In particular, an object of the present invention is to provide a substrate cleaning solution for a semiconductor device, which is hydrophobic and easily repels a chemical solution, and is excellent in cleanability of a low dielectric constant (Low-k) material having poor particle removability.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using an aqueous solution obtained by adding an organic acid and sulfosuccinic acid and / or a salt thereof to water as a cleaning liquid. The headline and the present invention were completed.
That is, the gist of the present invention is as follows.

[1] A substrate cleaning solution for a semiconductor device obtained by blending the following two components (A) and (B) and water.
(A) One or more selected from the group consisting of (A) organic acid (B) sulfosuccinic acid, alkyl sulfuric acid, alkyl ether sulfuric acid and salts thereof (hereinafter referred to as “component (B)”)

[2] A semiconductor device substrate cleaning solution according to [1], further comprising (C) an anionic surfactant other than the component (B).

[3] A substrate cleaning solution for a semiconductor device according to [1] or [2], wherein the organic acid is a polycarboxylic acid.

[4] The substrate cleaning solution for a semiconductor device according to any one of [1] to [3], wherein the pH is 1 to 5.

  According to the present invention, a semiconductor material such as silicon, an insulating material such as silicon nitride, silicon oxide, glass, and a low dielectric constant (Low-k) material, a transition metal, a transition metal compound, or the like is included on a part of or the entire surface. In semiconductor device substrates, fine particles (particles) adhering to the substrate surface, organic contamination, metal contamination, and organic-metal composite contamination are effectively removed by washing, and when fine particles etc. are mixed into the system. The reattachment can be effectively suppressed. In particular, the wettability of a hydrophobic low dielectric constant (Low-k) material that easily repels a chemical solution can be improved, and the detergency can be improved. Moreover, in addition to cleanability, it is possible to achieve both surface roughness suppression and low etching properties, so the present invention is used as a surface treatment technology for contamination cleaning in the manufacturing process of semiconductor devices and display devices. It is very useful industrially.

  Hereinafter, embodiments of the present invention will be described in detail.

The substrate cleaning solution for a semiconductor device of the present invention is prepared by mixing the following components (A) and (B) and water.
(A) Organic acid (B) One or more selected from the group consisting of sulfosuccinic acid, alkyl sulfuric acid, alkyl ether sulfuric acid and salts thereof

(A) The cleaning liquid of the present invention obtained by dissolving the organic acid and the component (B) in water has sufficient wettability even with a low-k material having strong hydrophobicity. Efficiently cleans and removes contamination of particles and organic substances attached to the substrate surface, metal contamination, and combined contamination of organic matter and metal, and at the same time, prevents reattachment, and does not cause substrate surface roughness or corrosion. Can be cleaned.
In the following, the weight ratio of each component to the total of all components including water used when preparing the substrate cleaning solution for a semiconductor device of the present invention is referred to as “preparation concentration”.

[Substrate cleaning solution for semiconductor devices]
<(A) Organic acid>
The organic acid (A) used in the present invention is not particularly limited as long as it is water-soluble, but organic carboxylic acids and / or organic sulfonic acids are preferred from the viewpoint of solubility and stability of the compound.

The organic carboxylic acid only needs to have one or more carboxyl groups, and may have a functional group other than the carboxyl group as long as the desired effect of the present invention is not impaired.
Examples of organic carboxylic acids include those having one carboxyl group such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, ethylmethylacetic acid, trimethylacetic acid, and succinic acid, succinic acid, malonic acid, maleic acid, Examples thereof include organic polycarboxylic acids having two or more carboxyl groups such as fumaric acid, citric acid, itaconic acid, glutaric acid, dimethylmalonic acid, citraconic acid, tartaric acid, malic acid, adipic acid and heptanoic acid. In terms of high solubility in the cleaning liquid and good dissolution stability, aliphatic polycarboxylic acids are preferable, and aliphatic polycarboxylic acids having 2 to 10 carbon atoms are particularly preferable. Preferred are succinic acid, malonic acid, succinic acid, tartaric acid, glutaric acid, malic acid, adipic acid and citric acid, and more preferred are malonic acid, tartaric acid and citric acid.

  Moreover, as typical organic sulfonic acid, aliphatic sulfonic acid such as methanesulfonic acid, ethanesulfonic acid, n-propanesulfonic acid, i-propanesulfonic acid, n-butanesulfonic acid, and aromatic such as phenylsulfonic acid. A sulfonic acid is mentioned. Among these, from the viewpoint of water solubility, alkylsulfonic acids such as methanesulfonic acid and ethanesulfonic acid are preferable, and methanesulfonic acid is more preferable.

  These organic acids may be used individually by 1 type, and may mix and use 2 or more types by arbitrary ratios.

  The preparation concentration of the (A) organic acid in the cleaning liquid of the present invention may be appropriately selected depending on the purpose, but is usually 0.01% by weight or more, preferably 0.05% by weight for ensuring cleaning properties. % Or more, more preferably 0.1% by weight or more, and usually 30% by weight or less, preferably 25% by weight or less, more preferably 20% by weight or less for dissolution stability in the cleaning liquid.

  These organic acids may be present in the cleaning solution as a salt with a cation. In this case, the cation is not particularly limited. For example, ammonium ion, primary, secondary, tertiary, or quaternary. Alkyl ammonium ion, alkali metal ion, phosphonium ion, sulfonium ion, or the like can be used. Of these, ammonium ions and alkylammonium ions are preferred, with alkylammonium ions being most preferred because they are less affected by diffusion / residue to the substrate metal due to metal ions remaining on the substrate surface. The alkyl group of the alkyl ammonium ion may be appropriately selected in consideration of the solubility in the cleaning liquid, but is usually an alkyl group having 1 to 4 carbon atoms.

<(B) component>
The component (B) used in the present invention is any of sulfosuccinic acid and / or its salt, alkyl sulfuric acid and / or its salt, alkyl ether sulfuric acid and / or its salt. Of these, sulfosuccinic acid and / or a salt thereof is particularly preferable.

  The sulfosuccinic acid and / or a salt thereof is a broadly-defined sulfosuccinic acid and / or a salt thereof, which is represented by the following general formula (I), in which the carboxyl group of the succinic acid moiety may be esterified.

（一般式（Ｉ）中、Ｒ^１，Ｒ^２は、各々独立に水素原子又は炭化水素基を表し、Ｘは水素原子、アルカリ金属原子、アルカリ土類金属原子又はアンモニウム塩基を表す。ただし、アルカリ土類金属原子の場合は、{（ＣＯＯＲ^１）（ＣＯＯＲ^２）ＣＨ_２ＣＨＳＯ_３}_２Ｘとなる。）

(In general formula (I), R ¹ and R ² each independently represents a hydrogen atom or a hydrocarbon group, and X represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, or an ammonium base. In the case of an earth metal atom, {(COOR ¹ ) (COOR ² ) CH ₂ CHSO ₃ } ₂ X is obtained.)

In the general formula (I), examples of the hydrocarbon group of R ¹ and R ² include an alkyl group, an alkenyl group, and an allyl group. R ¹ and R ² are preferably each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

The blending concentration of the component (B) in the cleaning liquid of the present invention has a lower limit of usually 0.0001% by weight, preferably 0.0005% by weight, more preferably 0.001% by weight, and the upper limit is usually 5% by weight. Preferably it is 1 weight%, More preferably, it is 0.5 weight%.
When the blending concentration of the component (B) is not less than the above lower limit, it is preferable in terms of particle contamination removal performance by the component (B), and when it is not more than the above upper limit, foaming hardly occurs and the waste liquid is biodegraded. This is preferable because it is difficult to increase the load.

[PH]
The cleaning liquid of the present invention is preferably an acidic cleaning liquid having a pH of 1 to 5, and more preferably the pH of the cleaning liquid is 2 or more. The upper limit of the pH of the cleaning liquid of the present invention is more preferably 4. When the pH of the cleaning solution is not less than the above lower limit, it is difficult to reach a part or the entire surface of the transition metal or transition metal compound exposed on the substrate surface, and the pH is not more than the above upper limit. It is preferable from the viewpoint of the removal of contamination and the effect of preventing re-adhesion. Therefore, among the (A) organic acid and (B) components of the cleaning liquid of the present invention and the other components described below, the mixing concentration of the component affecting the pH is within the range of the preferable mixing concentration. However, it is preferable to adjust appropriately so that it may become such a suitable pH.

<Preferred mixing ratio of components (A) and (B)>
In the cleaning liquid of the present invention, in order to sufficiently obtain the effects of the present invention by using the above-mentioned components (A) and (B) in combination, the blending concentration of (A) organic acid is set to the blending concentration of component (B). It is preferably 1 times by weight or more, more preferably 5 times by weight or more, still more preferably 10 times by weight or more, further preferably 5000 times by weight or less, and 1000 times by weight or less. It is more preferable that it is 500 weight times or less.
(A) The blending concentration of the organic acid is preferably not less than the above lower limit with respect to the blending concentration of the component (B), from the viewpoint of the removal of contamination and the effect of preventing reattachment. It is preferable that a part or the entire surface of the exposed transition metal or transition metal compound or the like is hardly corroded.

<(C) Anionic surfactant>
In the preparation of the cleaning liquid of the present invention, in order to improve the solubility of the component (B), a water-soluble (C) anionic surfactant other than the component (B) (hereinafter simply referred to as “anionic type”). It may be referred to as a “surfactant”.
Water-soluble anionic surfactants include alpha olefin sulfonic acid, alkyl sulfonic acid, alkyl benzene sulfonic acid, alkyl sulfate ester, alkyl ether sulfate ester, methyl tauric acid, ether sulfonic acid, polyacrylic acid and their salts. Of these, one or more can be preferably used. Among these, alkylbenzene sulfonic acid, methyl tauric acid, and salts thereof are preferable from the viewpoint of stability of the surfactant when added to the cleaning liquid and removal of particles such as fine particles, and the alkyl group particularly has 8 to 16 carbon atoms. Alkylbenzenesulfonic acid, especially dodecylbenzenesulfonic acid, is preferred.

  The preparation concentration of the (C) anionic surfactant when preparing the cleaning liquid of the present invention is usually 0.0001% by weight or more, preferably 0.0003% by weight or more, more preferably 0.001% by weight or more, It is particularly preferably 0.01% by weight or more, usually 5% by weight or less, preferably 1% by weight or less, more preferably 0.5% by weight or less, and particularly preferably 0.2% by weight or less. When the preparation concentration of the anionic surfactant is not less than the above lower limit, it is preferable in terms of the effect of improving the solubility of the component (B) due to the addition of the anionic surfactant, and is not more than the above upper limit. It is preferable that the load when the waste liquid is biodegraded is not excessive.

  In order to more reliably obtain the effect of improving the solubility of the component (B) without increasing the burden of biodegradation treatment of the waste liquid, the concentration of (C) the anionic surfactant is (B) It is preferably 0.005 times by weight or more, more preferably 0.01 times by weight or more, still more preferably 0.05 times by weight or more, and 1000 times by weight with respect to the blended concentration of the components. Is preferably 500 times by weight or less, more preferably 100 times by weight or less.

<(E) Complexing agent>
In the cleaning liquid of the present invention, it is preferable to further contain (E) a complexing agent because an extremely clean surface with further reduced metal contamination on the substrate surface can be obtained.
As the (E) complexing agent used in the present invention, any conventionally known complexing agent can be used. (E) The complexing agent should be selected based on comprehensive judgment from the contamination level of the substrate surface, the type of metal, the level of cleanliness required for the substrate surface, the cost of the complexing agent, chemical stability, and the like. The (E) complexing agent that can be used in the cleaning liquid of the present invention includes, for example, those shown below.

(1) Compounds having nitrogen as a donor atom and a carboxyl group and / or phosphonic acid group For example, amino acids such as glycine; iminodiacetic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid [EDTA], trans-1,2-diamino Nitrogen-containing carboxylic acids such as cyclohexanetetraacetic acid [CyDTA], diethylenetriaminepentaacetic acid [DTPA], triethylenetetraminehexaacetic acid [TTHA]; ethylenediaminetetrakis (methylenephosphonic acid) [EDTPO], nitrilotris (methylenephosphonic acid) [NTPO] And nitrogen-containing phosphonic acids such as propylenediaminetetra (methylenephosphonic acid) [PDTMP].

(2) having an aromatic hydrocarbon ring, and OH groups and / or bonded directly to a carbon atom constituting the ring O ^- Compound having two or more groups for example, catechol, resorcinol, phenols such as Tiron and And derivatives thereof.

(3) Compound having the structure of (1) and (2) above (3-1) Ethylenediaminediorthydroxyphenylacetic acid [EDDDHA] and its derivatives For example, ethylenediaminediorthydroxyphenylacetic acid [EDDDHA], ethylenediamine-N, N′-bis [(2-hydroxy-5-methylphenyl) acetic acid] [EDDHMA], ethylenediamine-N, N′-bis [(2-hydroxy-5-chlorophenyl) acetic acid] [EDDHCA], ethylenediamine-N, Aromatic nitrogen-containing carboxylic acids such as N′-bis [(2-hydroxy-5-sulfophenyl) acetic acid] [EDDHSA]; ethylenediamine-N, N′-bis [(2-hydroxy-5-methylphenyl) phosphonic acid ], Ethylenediamine-N, N′-bis [(2-hydroxy-5-phosphophe Le) an aromatic nitrogen-containing phosphonic acids such as phosphonic acid].
(3-2) N, N′-bis (2-hydroxybenzyl) ethylenediamine-N, N′-diacetic acid [HBED] and its derivatives For example, N, N′-bis (2-hydroxybenzyl) ethylenediamine-N, N′-diacetic acid [HBED], N, N′-bis (2-hydroxy-5-methylbenzyl) ethylenediamine-N, N′-diacetic acid [HMBED], N, N′-bis (2-hydroxy-5) -Chlorobenzyl) ethylenediamine-N, N'-diacetic acid.

(4) Others Amines such as ethylenediamine, 8-quinolinol and o-phenanthroline; Carboxylic acids such as formic acid and acetic acid; Hydrogen halides such as hydrofluoric acid, hydrochloric acid, hydrogen bromide and hydrogen iodide or salts thereof; Examples thereof include oxo acids such as phosphoric acid and condensed phosphoric acid, or salts thereof.

These complexing agents may be used in the acid form or in the form of a salt such as an ammonium salt.
Among the complexing agents described above, for reasons such as cleaning effect and chemical stability, amino acids such as glycine, nitrogen-containing carboxylic acids such as ethylenediaminetetraacetic acid [EDTA] and diethylenetriaminepentaacetic acid [DTPA]; ethylenediaminetetrakis (methylene) Nitrogen-containing phosphonic acids such as phosphonic acid) [EDTPO] and propylenediaminetetra (methylenephosphonic acid) [PDTMP]; ethylenediaminedioltohydroxyphenylacetic acid [EDDDHA] and its derivatives; N, N′-bis (2-hydroxybenzyl) Ethylenediamine-N, N′-diacetic acid [HBED] is preferred.

  Among them, from the viewpoint of the cleaning effect, enediaminediolhydroxyphenylacetic acid [EDDHA], ethylenediamine-N, N′-bis [(2-hydroxy-5-methylphenyl) acetic acid] [EDDHMA], diethylenetriaminepentaacetic acid [DTPA], ethylenediamine Tetraacetic acid [EDTA] and propylenediaminetetra (methylenephosphonic acid) [PDTMP] are preferred.

  These complexing agents may be used individually by 1 type, and may use 2 or more types together in arbitrary ratios.

  In the preparation of the cleaning liquid of the present invention, the preparation concentration of the complexing agent (E) may be arbitrarily selected according to the type and amount of contaminating metal impurities and the cleanliness level required for the substrate surface. 1 ppm by weight or more, especially 5 ppm by weight or more, particularly 10 ppm by weight or more and 10000 ppm by weight or less, particularly 1000 ppm by weight or less, and particularly preferably 200 ppm by weight or less. (E) It is preferable that the compounding concentration of the complexing agent is not less than the above lower limit from the viewpoint of the effect of contamination removal and adhesion prevention by the complexing agent, and on the other hand, it is economically advantageous if it is not more than the above upper limit. It is preferable because the risk that the agent is adhered and remains after the surface treatment is small.

  Since the complexing agent may contain about 1 to several thousand ppm by weight of metal impurities such as Fe in reagents that are usually sold, the complexing agent used in the present invention is a source of metal contamination. There are cases. These exist initially in the form of a stable complex with the complexing agent, but the complexing agent is decomposed and used as a surface treatment agent for a long time, and the metal is liberated to the surface of the substrate. It will adhere. Therefore, the complexing agent used in the present invention preferably contains not more than 5 ppm by weight of metal impurities such as Fe, Al, and Zn contained in advance, particularly preferably not more than 2 ppm by weight. . In order to obtain such a purified complexing agent, for example, after dissolving the complexing agent in an acidic or alkaline solution, insoluble impurities are separated by filtration, neutralized again to precipitate crystals, May be purified by separating the liquid from the liquid.

<Other ingredients>
The cleaning liquid of the present invention may further contain other components in an arbitrary ratio as long as the performance is not impaired.
Other components include alcohols and / or esters thereof, sulfur-containing organic compounds (2-mercaptothiazoline, 2-mercaptoimidazoline, 2-mercaptoethanol, thioglycerol, etc.), nitrogen-containing organic compounds (benzotriazole, 3-aminotriazole) , N (R) ₃ (R is an alkyl group having 1 to 4 carbon atoms), N (ROH) ₃ (R is an alkyl group having 1 to 4 carbon atoms), urea, thiourea, etc.), a water-soluble polymer (polyethylene glycol, Polyvinyl alcohol, etc.), anticorrosives such as alkyl alcohol compounds (ROH (R is an alkyl group having 1 to 4 carbon atoms)), acids such as sulfuric acid and hydrochloric acid, reducing agents such as hydrazine, dissolved hydrogen, argon, nitrogen, etc. Firmly after dry etching of gas, hydrofluoric acid, ammonium fluoride, BHF (buffered hydrofluoric acid), etc. Examples include etching accelerators that can be expected to remove attached polymers.

The alcohol as the other component may be a monohydric alcohol, a dihydric alcohol, or a trihydric or higher polyhydric alcohol. Moreover, some or all of the hydroxyl groups of these alcohols may be esterified.
Specific examples of the alcohol include propylene glycol and isopropanol, preferably propylene glycol. Examples of the alcohol ester include propylene glycol monoethyl acetate and propylene glycol monomethyl acetate of these alcohols, preferably propylene glycol and propylene glycol monoethyl acetate.
The concentration of these alcohols and / or esters thereof varies depending on the concentration of the component (B), but is usually 0.00001% by weight or more, preferably 0.0001% by weight or more, more preferably 0.001% by weight. %, Usually 5% by weight or less, preferably 2% by weight or less, more preferably 1% by weight or less.

  In addition, as other components that can be contained in the cleaning liquid of the present invention, oxidizing agents such as hydrogen peroxide, ozone, oxygen, and the like can be given. When cleaning the surface of a silicon (bare silicon) substrate without an oxide film in the step of cleaning a semiconductor device substrate, the surface roughness due to etching on the substrate surface can be suppressed by blending an oxidizing agent, which is preferable. When the cleaning liquid of the present invention contains an oxidizing agent such as hydrogen peroxide, the concentration is usually 0.001% by weight or more, particularly 0.01% by weight or more, and usually 5% by weight or less, particularly 1% by weight. It is preferable to use it as follows.

<Cleaning liquid medium>
The main medium of the cleaning liquid of the present invention is water. When a highly clean substrate surface is desired, deionized water, preferably ultrapure water is usually used. Further, electrolytic ion water obtained by electrolysis of water, hydrogen water in which hydrogen gas is dissolved in water, or the like can also be used.

<Formulation method>
The cleaning liquid preparation method of the present invention may be a conventionally known method.
Constituent components of the cleaning liquid, that is, (A) an organic acid, (B) component, and (D) anionic surfactant, (E) complexing agent, other components, and a medium used as necessary Any two or three or more components of water may be blended in advance, and then the remaining components may be mixed, or all may be mixed at once.

<Substrate to be cleaned (substrate for semiconductor device)>
The cleaning liquid of the present invention is used for cleaning the surface of a semiconductor device substrate such as a semiconductor, glass, metal, ceramics, resin, magnetic material, and superconductor in which metal contamination or particle contamination is a problem. In particular, it is suitably used for cleaning a semiconductor device substrate surface in a process of manufacturing a substrate for a semiconductor device such as a semiconductor element or a display device, which requires a highly clean substrate surface. Wirings, electrodes, and the like may be present on the surfaces of these substrates. Wiring and electrode materials include semiconductor materials such as Si, Ge, and GaAs; SiO ₂ , silicon nitride, glass, low dielectric constant (Low-k) materials, aluminum oxide, transition metal oxides (titanium oxide, tantalum oxide, Insulating materials such as hafnium oxide, zirconium oxide, etc.), (Ba, Sr) TiO ₂ (BST), polyimide, organic thermosetting resin; metals such as W, Cu, Al or alloys thereof, silicide, nitride, etc. Can be mentioned. Here, the Low-k material is a general term for materials having a relative dielectric constant of 3.5 or less, while the relative dielectric constant of silicon oxide such as TEOS is 3.8 to 3.9.

The cleaning liquid of the present invention is suitably used for cleaning the surface of a substrate for a semiconductor device regardless of the presence or absence of electrodes and wiring materials on the surface thereof. Among them, the cleaning liquid of the present invention is suitably used for cleaning a semiconductor device substrate having an insulating film on the surface and having a water contact angle of 50 ° or more on the substrate surface.
If the contact angle is large when cleaning the substrate, it will be easier to repel the chemical solution such as cleaning solution, and it will be insufficient to remove metal contamination on the substrate surface, particle contamination, and combined contamination with organic matter and metal. The contact angle is preferably 40 ° or less, more preferably 30 ° or less, and still more preferably 20 ° or less.

  In particular, the cleaning liquid of the present invention is suitably used for cleaning a semiconductor device substrate having a transition metal or a transition metal compound on its surface. Examples of the transition metal or transition metal compound in the present invention include W (tungsten), Cu (copper), Ti (titanium), Cr (chromium), Co (cobalt), Zr (zirconium), Hf (hafnium), and Mo (molybdenum). ), Ru (ruthenium), Au (gold), Pt (platinum), Ag (silver), and the like, and transition metal compounds such as nitrides, oxides, and silicides, preferably W (tungsten). ) And / or Cu (copper).

  The step of cleaning the substrate having copper on the surface includes cleaning of the substrate surface having the copper wiring and the interlayer insulating film when copper is used as the wiring material. Specifically, a cleaning process after forming a copper film on a semiconductor device, particularly a cleaning process after performing CMP (Chemical Mechanical Polishing) on the copper film, an interlayer insulating film on the copper wiring It is also applied for cleaning after opening a hole by dry etching. When cleaning the copper wiring, if the thickness of the copper wiring changes due to the cleaning, the wiring resistance is increased, and various characteristics such as wiring delay as a device are deteriorated. The etching amount in the cleaning is preferably 10 nm / min or less, more preferably 8 nm / min or less, and further preferably 5 nm / min or less.

  The cleaning liquid of the present invention is also suitably used for cleaning a semiconductor device substrate having a low dielectric constant (Low-k) material as an interlayer insulating film material on the surface. Low-k materials can be roughly divided into three categories: organic polymer materials, inorganic polymer (siloxane-based) materials, and porous (porous) materials. Examples of organic polymer materials include Polyimide, BCB (Benzocyclobutene), Flare (Honeywell), SiLK (Dow Chemical), etc., and inorganic polymer materials include FSG (Fluorinated silicate glass), BLACK DIAMOND (Applied Materials), Aurora (Japan ASM).

[Cleaning method of substrate cleaning solution for semiconductor devices]
A method for cleaning a substrate for a semiconductor device using the cleaning liquid of the present invention is usually performed by a method in which the cleaning liquid is brought into direct contact with the substrate. The contact method of the cleaning liquid to the substrate is a dip type in which the cleaning tank is filled with the cleaning liquid and the substrate is immersed, a spin type in which the substrate is rotated at high speed while flowing the cleaning liquid from the nozzle onto the substrate, and the substrate is cleaned by spraying the liquid on the substrate. A spray type etc. are mentioned. As an apparatus for performing such cleaning, there are a batch type cleaning apparatus for simultaneously cleaning a plurality of substrates accommodated in a cassette, a single wafer type cleaning apparatus for mounting and cleaning a single substrate on a holder, and the like. . It is not preferable that particles remain on the substrate after cleaning because it causes potential factors such as a change in dimensions of wiring and the like, a change in resistance, a disconnection, and a change in dielectric constant of an insulating film in a subsequent process.

  In the case of a batch type cleaning apparatus, the cleaning time is usually 30 seconds or more, preferably 1 minute or more, usually 30 minutes or less, preferably 15 minutes or less, and in the case of a single wafer cleaning apparatus, it is usually 1 second or more, preferably It is 5 seconds or longer, usually 15 minutes or shorter, preferably 5 minutes or shorter. When the cleaning time is not less than the above lower limit, it is preferable from the viewpoint of the cleaning effect, and when it is not more than the above upper limit, it is preferable that a decrease in throughput hardly occurs. Although the cleaning liquid of the present invention can be applied to any of the above methods, it is preferably used for spin-type or spray-type cleaning from the viewpoint of more efficient decontamination in a short time. As a type of the cleaning device, it is preferable to apply to a single wafer cleaning device in which shortening of the cleaning time and the amount of cleaning agent used are problems, because these problems are solved.

The temperature of the cleaning liquid is arbitrary and is usually room temperature. However, the cleaning liquid may be heated to about 40 ° C. or higher and 70 ° C. or lower for the purpose of improving the cleaning effect. That is, the cleaning with the cleaning liquid of the present invention can be carried out in a wide temperature range of usually 20 ° C. or higher and 70 ° C. or lower.
Furthermore, when cleaning a substrate with silicon exposed on the surface, organic contamination is likely to remain on the silicon surface, so the substrate is subjected to a heat treatment step at a temperature of 300 ° C. or higher, or is subjected to ozone water treatment. It is preferable to subject the organic matter to an oxidative decomposition treatment.

The cleaning method of the present invention is preferably used in combination with a cleaning method using physical force (physical cleaning), for example, mechanical cleaning such as scrub cleaning using a cleaning brush, or ultrasonic cleaning. In particular, it is preferable to use ultrasonic irradiation or brush scrub in combination because particle contamination can be further improved and cleaning time can be shortened.
In particular, a substrate subjected to CMP is preferably cleaned using a resin brush. The material of the resin brush used for brush cleaning is arbitrary, but for example, PVA (polyvinyl alcohol) is preferably used.
Further, it is preferable to irradiate the substrate with ultrasonic waves having a frequency of 0.5 megahertz or more because the removability of particles is remarkably improved by the synergistic action with the surfactant.
Furthermore, electrolytic ionic water obtained by electrolysis of water or cleaning with hydrogen water in which hydrogen gas is dissolved in water may be combined before and / or after the cleaning method of the present invention.

  EXAMPLES Next, although this invention is demonstrated more concretely using an Example, this invention is not limited by a following example, unless the summary is exceeded.

In the following, citric acid was used as the component (A), and “Sanmorin OT-70” (a propylene glycol solution of sodium sulfosuccinate) manufactured by Sanyo Chemical Industries, Ltd. was used as the component (B).
(C) Anionic surfactants other than the component (C) include “Polyty A-530” (an aqueous solution of sodium polyacrylate) and dodecylbenzenesulfonic acid (DBS) (Na, Mg, Al) manufactured by Lion Corporation. , K, Ca, Fe, Cu, Pb, and Zn are used in an amount of 1 ppm by weight or less).

Examples 1-4, Comparative Examples 1-4
A cleaning liquid was prepared with the formulation shown in Table 1 (however, the remainder: ultrapure water).
In preparation of the cleaning liquid, each component was simultaneously added to water (ultra pure water) as a medium and stirred and mixed.

  The obtained cleaning liquid was evaluated as follows, and the results are shown in Table 1.

<PH>
The pH of the prepared cleaning solution was measured with a pH meter (manufactured by Horiba, Ltd.).

<Contact angle with substrate>
A sample piece of 50 mm × 20 mm in which a low-k film (SiOC: carbon-containing SiO ₂ ) having a film thickness of 100 nm and washed with running ultrapure water for 10 minutes is prepared, and a predetermined amount of each cleaning solution is provided on the substrate. Is dropped using a droplet adjuster to form a droplet on the substrate, and after standing for 1 minute, the contact angle between the substrate and the droplet is measured using an image processing contact angle meter (CA manufactured by Kyowa Interface Science Co., Ltd.). -X150).
In addition, the contact angle with respect to the water of the board | substrate used for evaluation of a contact angle is 75 degrees.

<Cleanability of particle contamination by scrub cleaning>
An 8-inch silicon substrate with a Cu film was polished with a slurry for CMP containing a benzotriazole-based anticorrosive agent (acidic, containing SiO ₂ particles) for 1 minute, followed by water polishing for 17 seconds. The substrate after the CMP polishing is subjected to brush scrub cleaning using a PVA brush by a multi-spinner (“KSSP-201” manufactured by Kaijo Co., Ltd.) using a cleaning liquid having the composition shown in Table 1 to remove particles. did. The cleaning with the cleaning liquid was performed at room temperature for 30 seconds, and then the substrate was rinsed with ultrapure water for 10 seconds or 30 seconds and spin-dried to obtain a cleaned substrate. Thereafter, the number of particles (particle size of 0.35 μm or more) adhered to the substrate surface was measured using a laser surface inspection device (“LS-6600” manufactured by Hitachi Electronics Engineering Co., Ltd.). With respect to the surface foreign matter on the cleaned substrate, the cleaning property was evaluated by assuming that the number of foreign materials was 30 or more per substrate and that the cleaning was poor (x), and the number of foreign materials was less than 30 (good).

  From the above results, it is clear that the cleaning liquid of the present invention has a very small contact angle with respect to a hydrophobic low dielectric constant (Low-k) film and has good wettability.

Claims (4)

A substrate cleaning solution for a semiconductor device obtained by blending the following two components (A) and (B) and water.
(A) One or more selected from the group consisting of (A) organic acid (B) sulfosuccinic acid, alkyl sulfuric acid, alkyl ether sulfuric acid and salts thereof (hereinafter referred to as “component (B)”)   2. The substrate cleaning solution for a semiconductor device according to claim 1, further comprising (C) an anionic surfactant other than the component (B).   3. The substrate cleaning liquid for a semiconductor device according to claim 1, wherein the organic acid is a polycarboxylic acid.   The substrate cleaning solution for a semiconductor device according to any one of claims 1 to 3, wherein the pH is 1 to 5.