JP5817310B2 - Cleaning device and cleaning method for semiconductor device substrate - Google Patents

Description

  The present invention relates to a cleaning liquid for effectively cleaning a substrate surface for a semiconductor device having a metal exposed on the surface after a chemical mechanical polishing step.

  First, a semiconductor device substrate is formed by a chemical mechanical polishing using a polishing slurry made of an aqueous slurry containing fine particles after forming a metal film or interlayer insulating film deposited on a silicon wafer substrate. (Chemical Mechanical Polishing, hereinafter referred to as “CMP”), the surface is flattened, and a new layer is stacked on the flattened surface. In microfabrication of a substrate for a semiconductor device, high-precision flatness in each layer is required, and the importance of planarization by CMP is increasing.

On the other hand, in recent semiconductor device manufacturing processes, wiring (Cu wiring) made of a copper (Cu) film having a low resistance value has been introduced in order to increase the speed and integration of devices.
Cu is suitable for microfabrication due to its good workability, but it is easily oxidized and deteriorated in water, and is easily corroded by acidic components and alkali components. Therefore, oxidation and corrosion of Cu wiring are problematic in the CMP process. . Therefore, conventionally, in CMP of a semiconductor device substrate having Cu wiring, an anticorrosive agent such as benzotriazole or tolyltriazole is added to the polishing agent, and this anticorrosive agent is strongly adsorbed on the Cu surface to form a protective film. By doing so, corrosion of Cu wiring in CMP was suppressed (for example, refer patent document 1).

By the way, the semiconductor device substrate after the CMP process is subjected to a cleaning process in order to remove the Cu wiring and the insulating powder generated by the CMP.
Abrasive grains such as colloidal silica used in the CMP process remain on the substrate surface after the CMP process. Here, in the acidic aqueous solution, the colloidal silica is positively charged, whereas the substrate surface is negatively charged and an electric attractive force acts, so that it is difficult to remove the colloidal silica from the substrate surface. On the other hand, since OH ⁻ is abundant in an alkaline aqueous solution, both the colloidal silica and the substrate surface are negatively charged, and an electric repulsive force acts, so that the colloidal silica can be easily removed from the substrate surface.
Alkaline cleaning liquid makes it easy to remove particles such as colloidal silica, but also has a drawback that the Cu surface is oxidized. In order to prevent this oxidative deterioration and corrosion, a method of adding an anticorrosive agent to the cleaning liquid used in the cleaning process has been proposed. The anticorrosive agent conventionally used in CMP is a complex of Cu ions eluted from the Cu wiring and complex. There is a problem in that a residue having adhesion to the substrate is generated. On the other hand, when the anticorrosive agent with little residue generation known so far is used, the above-mentioned residue is not generated, but there is a problem that the oxidation deterioration and corrosion of the Cu wiring are insufficiently suppressed. Patent Document 2 discloses a metal corrosion inhibitor containing an amino acid having a thiol group in its molecule such as cysteine, but it was not sufficient in terms of avoiding residue formation.
As described above, no conventional cleaning liquid has been found that can achieve both corrosion resistance and avoidance of residue formation.

Japanese Patent No. 4406554 JP 2003-13266 A

  Under such circumstances, an object of the present invention is to be used in a cleaning process after a CMP process in a semiconductor device substrate, particularly a semiconductor device substrate having a metal wiring on the surface, and has sufficient anticorrosive properties against the metal wiring, It is to provide a cleaning liquid capable of suppressing generation and adhesion of residues to the substrate surface.

  As a result of intensive studies to solve the above problems, the present inventor has found that the following inventions meet the above object, and have reached the present invention.

That is, the present invention relates to the following inventions.
<1> The following components (A) ~ and also contains (E) respectively below a predetermined amount, p H is Ri der 10 or more and the weight ratio of component (C) to component (D) (C) / (D) = 1 / 1~2 / 1 in the range near Ru semiconductor device wafer cleaning solution.
(A) Organic quaternary ammonium hydroxide represented by general formula (1) : 1 to 25% by mass
(R ¹ ) ₄ N ⁺ OH ⁻ (1)
(However, R ¹ represents a hydroxyl group, an alkoxy group, or an alkyl group which may be substituted with halogen, and all four R ^{1 s} may be the same or different from each other.)
(B) Surfactant : 0.01 to 10% by mass
(C) At least one chelating agent selected from the group consisting of oxalic acid, citric acid, tartaric acid, malic acid, lactic acid, picolinic acid, ascorbic acid, gallic acid and acetic acid : 0.01 to 10% by mass
(D) An amino acid having at least one sulfur atom selected from the group consisting of N-acetyl-L-cysteine, cysteine and methionine : 0.1 to 10% by mass
(E) Water
<2> The substrate cleaning solution for a semiconductor device according to <1>, wherein the component (C) is citric acid or picolinic acid, and the component (D) is cysteine or N-acetyl-L-cysteine.
< 3 > The substrate cleaning solution for a semiconductor device according to <1> or <2> , wherein the component (B) is an anionic surfactant.
< 4 > Component (B) is selected from the group consisting of alkylsulfonic acid and its salt, alkylbenzenesulfonic acid and its salt, alkyldiphenyl ether disulfonic acid and its salt, alkylmethyl tauric acid and its salt, and sulfosuccinic acid diester and its salt The substrate cleaning solution for a semiconductor device according to < 3 >, which is at least one selected.
< 5 > Component (A) is 0.01 to 2.5% by mass, Component (B) is 0.0001 to 1% by mass, Component (C) is 0.0001 to 1% by mass, and Component (D). Is contained in a concentration of 0.001 to 1 mass%, the semiconductor device substrate cleaning solution according to any one of <1> to < 4 >.
< 6 > A method for cleaning a semiconductor device substrate, wherein the semiconductor device substrate is cleaned using the semiconductor device substrate cleaning liquid according to any one of <1> to < 5 >.
<7> substrate for a semiconductor device has a Cu wiring and a low dielectric constant insulating film on the substrate surface, and, according to <6> cleaning the semiconductor device substrate after chemical mechanical polishing A method for cleaning a substrate for a semiconductor device.

  By using the cleaning liquid of the present invention, the semiconductor device substrate cleaning process after the CMP process has sufficient anticorrosive properties against metal wiring, and the generation of residues and the adhesion of residues to the substrate surface can be suppressed. .

It is a SEM photograph of the pattern substrate after being immersed in the cleaning liquid (dilution liquid) of Example 1 for 30 minutes. It is a SEM photograph of the pattern substrate after being immersed in the cleaning liquid (dilution liquid) of Example 2 for 30 minutes. It is a SEM photograph of the pattern substrate after being immersed in the cleaning liquid (dilution liquid) of Example 3 for 30 minutes. It is a SEM photograph of the pattern substrate after being immersed in the washing | cleaning liquid (dilution liquid) of Example 4 for 30 minutes. It is a SEM photograph of the pattern substrate after being immersed in the cleaning liquid (dilution liquid) of Example 5 for 30 minutes. It is a SEM photograph of the pattern substrate after being immersed in the washing | cleaning liquid (dilution liquid) of the comparative example 1 for 30 minutes. It is a SEM photograph of the pattern substrate after being immersed in the washing | cleaning liquid (dilution liquid) of the comparative example 2 for 30 minutes. It is a SEM photograph of a pattern board after being immersed in a washing liquid (dilution liquid) of comparative example 3 for 30 minutes. It is a SEM photograph of the pattern substrate after being immersed in the washing | cleaning liquid (dilution liquid) of the comparative example 4 for 30 minutes.

This invention contains the following components (A)-(E), and pH is 10 or more, The board | substrate washing | cleaning liquid for semiconductor devices characterized by the above-mentioned.
(A) Organic quaternary ammonium hydroxide represented by the general formula (1)
(R ¹ ) ₄ N ⁺ OH ⁻ (1)
(However, R ¹ represents a hydroxyl group, an alkoxy group, or an alkyl group which may be substituted with halogen, and all four R ^{1 s} may be the same or different from each other.)
(B) Surfactant (C) Chelating agent (D) Amino acid having sulfur atom (E) Water

In the alkaline liquid, since OH ⁻ is abundant, the particle surface such as colloidal silica is negatively charged, and the surface of the substrate to be cleaned is similarly negatively charged. When the zeta potential in the liquid is controlled to the same sign, an electric repulsive force is generated. As a result, the removal of the particles from the substrate surface can be facilitated, and the particles once removed can be prevented from reattaching to the substrate surface.
The pH in the cleaning liquid of the present invention can be adjusted by the amount of each component contained in the cleaning liquid.

Usually, in an alkaline solution, Cu (hereinafter sometimes referred to as “Cu wiring”) present as wiring or the like on the surface of a semiconductor device substrate is oxidized to become copper oxide. Copper oxide is dissolved by a chelating agent or the like in the cleaning solution and causes corrosion, but in the present invention, excessive oxidation of the Cu wiring can be prevented by the action of the anticorrosive agent in the cleaning solution.
In order for the anticorrosive to exhibit anticorrosion performance, a film of a copper-anticorrosive complex is required to be formed on the wiring surface, and the solubility of the film is required to be low. However, when the solubility of the copper-corrosion inhibitor complex is too low, it cannot be removed in the cleaning step, and there is a problem that it remains as a crystal or an organic residue on the Cu wiring. In an acidic solution, the dissociation of amino groups and carboxyl groups is small, the solubility of the copper-corrosion inhibitor complex becomes low, and it remains as a crystal on the Cu wiring. The solubility is improved and it is difficult to remain on the Cu wiring.
From the above, in the cleaning liquid of the present invention, due to the presence of the above components (A) to (D), it has sufficient anticorrosive properties for metal wiring and can suppress the generation of residues and the adhesion of residues to the substrate surface. it can.

  Hereinafter, each component contained in the cleaning liquid of the present invention will be described in detail together with its action.

Component (A): Organic quaternary ammonium hydroxide The organic quaternary ammonium hydroxide (component (A)) used in the cleaning liquid of the present invention is represented by the following general formula (1).
(R ¹ ) ₄ N ⁺ OH ⁻ (1)
(However, R ¹ represents a hydroxyl group, an alkoxy group, or an alkyl group which may be substituted with halogen, and all four R ^{1 s} may be the same or different from each other.)

Component (A) is contained in the cleaning liquid in order to control the pH within the above range. Here, since the organic quaternary ammonium hydroxide is inactive with respect to the Cu wiring, it does not cause corrosion.
Other organic alkalis such as primary amine, secondary amine, and tertiary amine form a complex with copper and dissolve, thereby causing corrosion of the Cu wiring. In the case of inorganic alkali, contained potassium, sodium and the like remain on the surface of the substrate, so that the cleaning effect is insufficient.

As the quaternary ammonium hydroxide, in the general formula (1), R ¹ is a hydroxyl group, an alkoxy group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms which may be substituted with halogen. Particularly preferred are alkyl groups having 1 to 3 carbon atoms and / or hydroxyalkyl groups having 1 to 3 carbon atoms. The alkyl group of R ¹ is a lower alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, or a propyl group, and the hydroxyalkyl group is an alkyl group having 1 to 1 carbon atoms such as a hydroxymethyl group, a hydroxyethyl group, or a hydroxypropyl group. 3 lower hydroxyalkyl groups.

  Specific examples of the quaternary ammonium hydroxide include tetramethylammonium hydroxide (TMAH), bishydroxyethyldimethylammonium, tetraethylammonium hydroxide, trimethyl (hydroxyethyl) ammonium hydroxide (common name: choline), and triethyl. (Hydroxyethyl) ammonium hydroxide and the like.

  Among the above-mentioned organic alkali components, tetramethylammonium hydroxide, bishydroxyethyldimethylammonium, trimethyl (hydroxyethyl) ammonium hydroxide, etc. are used for reasons such as cleaning effect, low metal residue, economy, and stability of cleaning liquid. Particularly preferred. These organic alkali components may be used individually by 1 type, and may use 2 or more types together by arbitrary ratios.

Component (B): Surfactant Since the surface of the interlayer insulating film is hydrophobic, it is difficult to clean it with a cleaning liquid based on water. The surfactant has an action of improving the hydrophilicity of the hydrophobic substrate surface. By improving the affinity with the substrate surface, the action of the cleaning liquid can be exerted between particles existing on the substrate and the like, which can contribute to the removal. In a cleaning solution that does not contain a surfactant, the cleaning effect is insufficient because the affinity between the cleaning solution and the hydrophobic substrate surface is low. In the present invention, any of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant can be used.

An example of a surfactant that can be suitably used in the cleaning liquid of the present invention is an anionic surfactant. Examples of anionic surfactants include alkyl sulfonic acids and salts thereof, alkyl benzene sulfonic acids and salts thereof, alkyl diphenyl ether disulfonic acids and salts thereof, alkyl methyl tauric acids and salts thereof, and sulfosuccinic acid diesters and salts thereof. Specific examples include dodecylbenzenesulfonic acid, dodecanesulfonic acid, and alkali metal salts thereof. Among these, dodecylbenzenesulfonic acid and its alkali metal salt are preferably used because of the stability of quality and availability.
Another example of the anionic surfactant is a carboxylic acid type anionic surfactant. An anionic surfactant containing a carboxyl group in the molecule, among which a compound represented by the following general formula (1) is preferred.
R—O— (AO) _m — (CH ₂ ) _n —COOH (1)

In General formula (1), R is a linear or branched alkyl group, and the carbon number is 8-15, Preferably, it is 10-13. AO is an oxyethylene group and / or oxypropylene group, and m is 3 to 30, preferably 4 to 20, and more preferably 4.5 to 10. N is 1 to 6, preferably 1 to 3. Specific examples of the compound represented by the general formula (1) include polyoxyethylene lauryl ether acetic acid, polyoxyethylene tridecyl ether acetic acid, and polyoxyethylene alkyl ether acetic acid.
In addition, anionic surfactant may be used individually by 1 type, and may use 2 or more types together by arbitrary ratios.

Particularly preferred sulfonic acid type anionic surfactants include dodecylbenzene sulfonic acid (DBS), dodecane sulfonic acid, and alkali metal salts thereof.
Among these, dodecylbenzenesulfonic acid and its alkali metal salt are preferably used because of the stability of quality and availability.

  In addition, the surfactant may contain metal impurities such as Na, K, and Fe of about 1 to several thousand mass ppm in a commercially available form. In this case, the surfactant is a metal. It becomes a pollution source. Therefore, when the component (B) contains metal impurities, the component (B) is such that the content of each metal impurity is usually 10 ppm or less, preferably 1 ppm or less, more preferably 0.3 ppm or less. Is preferably used after purification. As this purification method, for example, a method in which the component (B) is dissolved in water and then passed through an ion exchange resin to capture metal impurities in the resin is suitable. By using the surfactant thus purified, it is possible to obtain a cleaning liquid in which the content of metal impurities is extremely reduced.

Component (C): Chelating agent The chelating agent (component (C)) is an impurity metal such as tungsten contained in the metal wiring on the substrate surface, or an anticorrosive agent and copper present in the barrier slurry used in the CMP process. Insoluble metal complexes, and alkali metals such as sodium and potassium are dissolved and removed by chelating action.
As the chelating agent, organic acids, inorganic acids, amines and salts thereof or derivatives thereof having the above-described action can be used, and one kind may be used alone, or two or more kinds may be used in an arbitrary ratio. You may use together.
As component (C), at least one selected from the group consisting of oxalic acid, citric acid, tartaric acid, malic acid, lactic acid, picolinic acid, ascorbic acid, gallic acid, acetic acid, ethylenediamine, aminoethanol, ethylenediaminetetraacetic acid and ammonia, in particular Preferably it is a seed. Moreover, these salts can also be used suitably.

Component (D): Amino acid having a sulfur atom The amino acid having a sulfur atom used in the cleaning liquid of the present invention has a property of adsorbing to heavy metals such as copper. Therefore, the inclusion in the cleaning liquid covers the surface of the metal wiring of the substrate for a semiconductor device and has an action of preventing the metal wiring from being corroded.
Here, the amino acid having a sulfur atom is preferably an amino acid having a thiol group or a thioether group.
In particular, at least one selected from the group consisting of N-acetyl-L-cysteine, cysteine and methionine is preferable.
These compounds have an excellent anticorrosive action, high safety, and high solubility in water, so that they can be easily dissolved in (E) water, which is the solvent of the cleaning liquid of the present invention. There is.

Component (E): Water (E) Water is used as the solvent in the cleaning liquid of the present invention, and it is preferable to use deionized water or ultrapure water in which impurities are reduced as much as possible.

In addition, the cleaning liquid of the present invention may contain components other than the above components (A) to (E) in an arbitrary ratio as long as the performance is not impaired.
Examples of other components include benzotriazole, 3-aminotriazole, N (R ² ) ₃ (R ² may be the same as or different from each other, and an alkyl group having 1 to 4 carbon atoms and / or 1 to 1 carbon atom. 4 hydroxyalkyl group), nitrogen-containing organic compounds such as urea and thiourea,
Water-soluble polymers such as polyethylene glycol and polyvinyl alcohol,
Anticorrosives such as alkyl alcohol compounds such as R ³ OH (R ³ is an alkyl group having 1 to 4 carbon atoms);
Dissolved gases such as hydrogen, argon, nitrogen, carbon dioxide, ammonia,
Etching accelerators that can be expected to remove polymers that adhere strongly after dry etching, such as hydrofluoric acid, ammonium fluoride, and BHF (buffered hydrofluoric acid);
Reducing agents such as hydrazine;
Oxidizing agents such as hydrogen peroxide, ozone, oxygen;
Alkanolamines such as monoethanolamine, diethanolamine, triethanolamine;
Etc.
Moreover, components other than water, such as ethanol, may be included as a solvent.

The method for producing the cleaning liquid of the present invention is not particularly limited and may be a conventionally known method. For example, the components of the cleaning liquid (components (A) to (E), and other components as necessary) are mixed. Can be manufactured. Usually, it manufactures by adding component (A)-(D) and another component to (E) water which is a solvent.
The mixing order is arbitrary as long as there is no particular problem such as reaction or precipitation, and any two components or three or more components among the components of the cleaning liquid are blended in advance, and then the remaining components are mixed. Or you may mix all at once.

The cleaning liquid of the present invention can be manufactured by adjusting the concentration of each component so that the concentration is suitable for cleaning. However, from the viewpoint of reducing the cost during transportation and storage, each component is highly concentrated. In many cases, the cleaning solution is contained (hereinafter sometimes referred to as “cleaning stock solution”) and then diluted with water.
The concentration of each component in this washing stock solution is not particularly limited, but components (A) to (D) and other components added as necessary, and these reactants may be separated in the washing stock solution, It is preferable that it is the range which does not precipitate.
Specifically, the preferred concentration range of the cleaning stock solution is that component (A) is 1 to 25% by mass, component (B) is 0.01 to 10% by mass, and component (C) is 0.01 to 10 mass% and a component (D) are the density | concentrations of 0.1-10 mass%.
In such a concentration range, it is difficult to separate the contained components during transportation and storage, and (E) it can be suitably used as a cleaning solution having a concentration suitable for easy cleaning by adding water. it can.

The concentration of each component of the cleaning liquid when cleaning the semiconductor device substrate is appropriately determined according to the semiconductor device substrate to be cleaned.
The cleaning solution used for cleaning may be manufactured by diluting the cleaning stock solution so that the concentration of each component is appropriate with respect to the semiconductor device substrate to be cleaned. You may adjust and manufacture each component directly.

The concentration of component (A): organic quaternary ammonium hydroxide when used as a cleaning liquid is preferably 0.01 to 2.5% by mass, more preferably 0.05 to 1% by mass.
If the concentration of the component (A) is less than 0.01% by mass, it may not be possible to remove the contamination of the semiconductor device substrate, and if it exceeds 2.5% by mass, no further effect can be obtained. In addition, the cost of the cleaning liquid is increased.

The concentration of component (B): surfactant when used as a cleaning liquid is preferably 0.0001 to 1% by mass, more preferably 0.0003 to 0.1% by mass, and still more preferably 0, with respect to the cleaning liquid. 0.001 to 0.1% by mass.
If the concentration of the component (B) is too low, the effect of adding the surfactant becomes insufficient, and if the concentration of the component (B) is too high, no further effect can be obtained, excessive foaming occurs, Increase the waste treatment load.

The concentration of component (C): chelating agent when used as a cleaning liquid is preferably 0.0001 to 1% by mass, more preferably 0.0003 to 0.1% by mass, and still more preferably 0.001% by mass with respect to the cleaning liquid. It is 001-0.1 mass%.
If the concentration of the component (C) is too low, there is a possibility that the removal of contamination of the substrate for semiconductor devices may be insufficient, and if the concentration exceeds 1% by mass, no further effect can be obtained, and the cost of the cleaning liquid Will take more. In addition, when the concentration of the component (C) exceeds 3% by mass, a problem such as corrosion of metal wiring such as Cu may be caused.

Component (D) when used as a cleaning liquid: The concentration of the amino acid having a sulfur atom is preferably 0.001 to 1 mass%, more preferably 0.001 to 0.5 mass%, based on the cleaning liquid.
If the concentration of component (A) is less than 0.001% by mass, removal of contamination of the substrate for semiconductor devices may be insufficient, and if it exceeds 1% by mass, no further effect can be obtained. In addition, the cost of the cleaning liquid is increased. Further, when the concentration of the component (A) exceeds 1% by mass, a problem such as corrosion of metal wiring such as Cu may be caused.

Next, the cleaning method of the present invention will be described.
The cleaning method of the present invention is performed by a method in which the above-described cleaning liquid of the present invention is brought into direct contact with a semiconductor device substrate.

Examples of semiconductor device substrates to be cleaned include various semiconductor device substrates such as semiconductors, glasses, metals, ceramics, resins, magnetic materials, and superconductors.
Among these, since the cleaning liquid of the present invention can be removed by rinsing in a short time, it is suitable for a substrate for a semiconductor device having a metal or a metal compound on the surface as a wiring, and particularly has a Cu wiring on the surface. This is suitable for semiconductor device substrates.

  Here, examples of the metal used for the semiconductor device substrate include W, Cu, Ti, Cr, Co, Zr, Hf, Mo, Ru, Au, Pt, and Ag. Examples thereof include nitrides, oxides, silicides, and the like of these metals. Among these, Cu and compounds containing these are suitable targets.

Further, the cleaning method of the present invention is suitable for a semiconductor device substrate having a low dielectric constant insulating material because the cleaning effect is high even for a low dielectric constant insulating material having strong hydrophobicity.
Examples of such a low dielectric constant material include organic polymer materials such as Polyimide, BCB (Benzocyclobutylene), Flare (Honeywell), SiLK (Dow Chemical), FSG (Fluorinated silicate glass), and BLACK AM (Dlack AM). Examples thereof include SiOC-based materials such as Applied Materials) and Aurora (Japan ASM).

  Here, the cleaning method of the present invention is particularly preferably applied when the substrate for a semiconductor device has Cu wiring and a low dielectric constant insulating film on the substrate surface and the substrate is cleaned after the CMP process. In the CMP process, polishing is performed by rubbing the substrate against the pad using an abrasive.

The abrasive includes abrasive particles such as colloidal silica (SiO ₂ ), fumed silica (SiO ₂ ), alumina (Al ₂ O ₃ ), and ceria (CeO ₂ ). Such abrasive particles are a major cause of contamination of the semiconductor device substrate. However, the cleaning liquid of the present invention has a function of dispersing the fine particles adhering to the substrate in the cleaning liquid and preventing re-adhesion. High effect of particulate contamination.

Further, the abrasive may contain additives other than abrasive particles such as an oxidizing agent and a dispersant.
In particular, in CMP polishing on a semiconductor device substrate having Cu wiring as a metal wiring on its surface, an anticorrosive agent is often added because Cu wiring is easily corroded.
As the anticorrosive, an azole anticorrosive having a high anticorrosive effect is preferably used. More specifically, a diazole type, a triazole type, or a tetrazole type containing a nitrogen-only heterocyclic ring may be mentioned. Examples include oxazole, isoxazole, and oxadiazole systems that include nitrogen and oxygen heterocycles, and thiazole, isothiazole, and thiadiazole systems that include nitrogen and sulfur heterocycles. Among them, a benzotriazole (BTA) anticorrosive having an excellent anticorrosion effect is particularly preferably used.

When the cleaning liquid of the present invention is applied to the surface after polishing with an abrasive containing such an anticorrosive, it is excellent in that it can very effectively remove contamination derived from these anticorrosive.
That is, when these anticorrosives are present in the polishing agent, while suppressing the corrosion of the Cu wiring surface, it reacts with Cu ions eluted during polishing to produce a large amount of insoluble precipitates. The cleaning liquid of the present invention can efficiently dissolve and remove such insoluble precipitates, and further can remove the surfactant that tends to remain on the metal surface by rinsing in a short time, thereby improving the throughput. Is possible.
Therefore, the cleaning method of the present invention is suitable for cleaning a substrate for a semiconductor device after the CMP treatment is performed on the surface where the Cu wiring and the low dielectric constant insulating film coexist, and in particular, a polishing agent containing an azole anticorrosive is used for CMP. It is suitable for cleaning the treated substrate.

  As described above, the cleaning method of the present invention is performed by a method in which the cleaning liquid of the present invention is brought into direct contact with the semiconductor device substrate. A cleaning liquid having a suitable component concentration is selected according to the type of the semiconductor device substrate to be cleaned.

  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 sprayed and cleaned. A spray type etc. are mentioned. As an apparatus for performing such cleaning, there are a batch-type cleaning apparatus that simultaneously cleans a plurality of substrates housed in a cassette, a single-wafer cleaning apparatus that mounts and cleans a single substrate in a holder, and the like. .

  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 because it allows more efficient decontamination in a short time. And if it applies to the single wafer type washing | cleaning apparatus with which shortening of washing | cleaning time and reduction of the usage-amount of washing | cleaning liquid are desired, since these problems are solved, it is preferable.

  In addition, the cleaning method of the present invention is capable of removing contamination caused by fine particles adhering to the substrate when used in combination with a cleaning method based on physical force, particularly scrub cleaning using a cleaning brush or ultrasonic cleaning with a frequency of 0.5 MHz or higher. This is preferable because it further improves and shortens the cleaning time. In particular, in the cleaning after CMP, it is preferable to perform scrub cleaning using a resin brush. The material of the resin brush can be arbitrarily selected, but for example, PVA (polyvinyl alcohol) is preferably used.

  Furthermore, you may perform the washing | cleaning by water before and / or after the washing | cleaning by the washing | cleaning method of this invention.

  In the cleaning method of the present invention, the temperature of the cleaning solution is usually room temperature, but may be heated to about 40 to 70 ° C. within a range not impairing performance.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is changed.

Example 1
(Preparation of washing solution stock solution)
Component (A): Tetramethylammonium hydroxide (TMAH), Component (B): Dodecylbenzenesulfonic acid (DBS), Component (C): Citric acid, Component (D): N-acetyl-L-cysteine E): Mixed with water to prepare a stock solution of the substrate cleaning liquid for semiconductor devices of Example 1 having the composition shown in Table 1. Next, water was added to the cleaning solution stock solution to prepare a semiconductor cleaning solution (diluted solution) diluted 40 times. Table 1 shows the composition of the stock solution and the diluted solution.

(PH measurement)
The pH was measured with a pH meter (Horiba, Ltd. D-24) while stirring the cleaning solution diluted 40 times using a magnetic stirrer. The measurement sample kept the liquid temperature at 25 degreeC in the thermostat. The measurement results are shown in Table 2.

(Evaluation of corrosiveness)
Washing solution prepared by diluting 40 times by preparing two sheets of pattern substrate (CMP4-TEG manufactured by Next Generation Semiconductor Materials Technology Research Association) including a comb pattern of Cu wiring with 90nm / 90nm line / space It was immersed in each for 10 minutes at 40 ° C. for 30 minutes. The substrate after immersion was taken out and immediately washed with ultrapure water and dried by air blow.
The substrate after the immersion was observed with an electrolytic emission scanning electron microscope (JSM-6320F manufactured by JEOL Ltd.), and the results of evaluation of corrosion resistance are shown in Table 2. In addition, anticorrosion is judged by the progress of corrosion of Cu wiring pattern, and the description in Table 2 is as follows.

○: Corrosion was not confirmed.
Δ: Some corrosion was confirmed.
X: Corrosion was confirmed.

FIG. 1 shows an SEM photograph of the pattern substrate after being immersed in a cleaning solution (diluted solution) for 30 minutes.

Example 2
(Preparation of washing solution stock solution)
Component (A): Bishydroxyethyldimethylammonium (AH212, Yokkaichi Synthesis Co., Ltd.), Component (B): DBS, Component (C): Citric acid, Component (D): N-acetyl-L-cysteine (E ): Mixed with water to prepare a stock solution of the substrate cleaning liquid for semiconductor device of Example 2 having the composition shown in Table 1. Next, water was added to the cleaning solution stock solution to prepare a semiconductor cleaning solution (diluted solution) diluted 40 times. Table 1 shows the composition of the stock solution and the diluted solution. Using the obtained cleaning liquid, pH measurement and corrosive evaluation were performed in the same manner as in Example 1. The results are shown in Table 2. FIG. 2 shows an SEM photograph of the pattern substrate after being immersed in a cleaning solution (diluted solution) for 30 minutes.

Example 3
(Preparation of washing solution stock solution)
Ingredient (A): TMAH, Ingredient (B): DBS, Ingredient (C): Picolinic acid, Ingredient (D): N-acetyl-L-cysteine is mixed with Ingredient (E): Water and shown in Table 1. A stock solution of the substrate cleaning liquid for semiconductor devices of Example 3 of the composition was prepared. Next, water was added to the cleaning solution stock solution to prepare a semiconductor cleaning solution (diluted solution) diluted 40 times. Table 1 shows the composition of the stock solution and the diluted solution. Using the obtained cleaning liquid, pH measurement and corrosive evaluation were performed in the same manner as in Example 1. The results are shown in Table 2. FIG. 3 shows an SEM photograph of the pattern substrate after being immersed in a cleaning solution (diluted solution) for 30 minutes.

Example 4
(Preparation of washing solution stock solution)
Ingredient (A): TMAH, Ingredient (B): DBS, Ingredient (C): Picolinic acid, Ingredient (D): N-acetyl-L-cysteine is mixed with Ingredient (E): Water and shown in Table 1. A stock solution of the substrate cleaning liquid for semiconductor devices of Example 4 of the composition was prepared. Next, water was added to the cleaning solution stock solution to prepare a semiconductor cleaning solution (diluted solution) diluted 40 times. Table 1 shows the composition of the stock solution and the diluted solution. Using the obtained cleaning liquid, pH measurement and corrosive evaluation were performed in the same manner as in Example 1. The results are shown in Table 2. FIG. 4 shows an SEM photograph of the pattern substrate after being immersed in a cleaning solution (diluted solution) for 30 minutes.

Example 5
(Preparation of washing solution stock solution)
Component (A): TMAH, Component (B): DBS, Component (C): Citric acid, Component (D): Cysteine is mixed with Component (E): Water, and the composition of Example 5 shown in Table 1 A stock solution of a substrate cleaning solution for a semiconductor device was prepared. Next, water was added to the cleaning solution stock solution to prepare a semiconductor cleaning solution (diluted solution) diluted 40 times. Table 1 shows the composition of the stock solution and the diluted solution. Using the obtained cleaning liquid, pH measurement and corrosive evaluation were performed in the same manner as in Example 1. The results are shown in Table 2. FIG. 5 shows an SEM photograph of the pattern substrate after being immersed in a cleaning solution (diluted solution) for 30 minutes.

Comparative Example 1
(Preparation of washing solution stock solution)
Component (A): TMAH, Component (B): DBS, Component (C): Picolinic acid is mixed with Component (E): Water, and a stock solution of a substrate cleaning solution for a semiconductor device of Comparative Example 1 having the composition shown in Table 1 Was prepared. Next, water was added to the cleaning solution stock solution to prepare a semiconductor cleaning solution (diluted solution) diluted 40 times. Table 1 shows the composition of the stock solution and the diluted solution. Using the obtained cleaning liquid, pH measurement and corrosive evaluation were performed in the same manner as in Example 1. The results are shown in Table 3. FIG. 6 shows an SEM photograph of the pattern substrate after being immersed in a cleaning solution (diluted solution) for 30 minutes.

Comparative Example 2
(Preparation of washing solution stock solution)
Ingredient (A): TMAH, ingredient (B): DBS, ingredient (C): citric acid, 1,2,4-triazole as an anticorrosive agent instead of ingredient (D), mixed with ingredient (E): water A stock solution of a substrate cleaning solution for a semiconductor device of Comparative Example 2 having the composition shown in Table 1 was prepared. Next, water was added to the cleaning solution stock solution to prepare a semiconductor cleaning solution (diluted solution) diluted 40 times. Table 1 shows the composition of the stock solution and the diluted solution. Using the obtained cleaning liquid, pH measurement and corrosive evaluation were performed in the same manner as in Example 1. The results are shown in Table 3. FIG. 7 shows an SEM photograph of the pattern substrate after being immersed in a cleaning solution (diluted solution) for 30 minutes.

Comparative Example 3
(Preparation of washing solution stock solution)
Ingredient (A): TMAH, Ingredient (B): DBS, Ingredient (C): Citric acid, BT-250 (Johoku Chemical Co., Ltd.) as an anticorrosive agent instead of Ingredient (D), Ingredient (E): Water And a stock solution of the semiconductor device substrate cleaning liquid of Comparative Example 3 having the composition shown in Table 1 was prepared. Next, water was added to the cleaning solution stock solution to prepare a semiconductor cleaning solution (diluted solution) diluted 40 times. Table 1 shows the composition of the stock solution and the diluted solution. Using the obtained cleaning liquid, pH measurement and corrosive evaluation were performed in the same manner as in Example 1. The results are shown in Table 3. FIG. 8 shows an SEM photograph of the pattern substrate after being immersed in a cleaning solution (diluted solution) for 30 minutes.

Comparative Example 4
(Preparation of washing solution stock solution)
Component (B): DBS, Component (C): Citric acid, Component (D): N-acetyl-L-cysteine was mixed with component (E) water, and the semiconductor device of Comparative Example 4 having the composition shown in Table 1 A stock solution of a substrate cleaning solution was prepared. Next, water was added to the cleaning solution stock solution to prepare a semiconductor cleaning solution (diluted solution) diluted 40 times. Table 1 shows the composition of the stock solution and the diluted solution. Using the obtained cleaning liquid, pH measurement and corrosive evaluation were performed in the same manner as in Example 1. The results are shown in Table 3. FIG. 9 shows an SEM photograph of the pattern substrate after being immersed in a cleaning solution (diluted solution) for 30 minutes.

  In Examples 1 to 4, the stock solution of the cleaning solution contained component (D): N-acetyl-L-cysteine, and the results of the corrosive evaluation shown in Table 2 were represented by ◯, and good results were obtained. . Good results were obtained regardless of the combination of TMAH and AH212 as the component (A) organic alkali and citric acid and picolinic acid as the component (C) chelating agent.

  In Example 5, the component (D): cysteine was contained, and the result of the corrosive evaluation shown in Table 2 was represented by ◯, and a good result was obtained.

  In Comparative Example 1, component (D) is not added. As shown in Table 3, the result of the immersion for 30 minutes is represented by x, and the Cu wiring surface state is greatly changed as the result of FIG. Such a change in the Cu wiring surface has an adverse effect on the substrate cleaning, and the cleaning agent having the composition shown in Comparative Example 1 does not give a good cleaning result.

  In Comparative Example 2, 1,2,4-triazole is included as an anticorrosive agent instead of component (D). The results of the immersion for 30 minutes shown in Table 3 are represented by x, and as shown in the results of FIG. 7, dissolution is progressing in the entire Cu wiring, and the progress of remarkable corrosion can be confirmed. Compared with Example 1, 1,2,4-triazole has weaker anticorrosion performance than N-acetyl-L-cysteine, and the required anticorrosion performance is not satisfied.

  In the comparative example 3, BT-250 is included as an anticorrosive agent instead of a component (D). The result of immersion for 30 minutes shown in Table 3 is represented by x. As shown in the result of FIG. 8, dissolution is progressing in the entire Cu wiring, and remarkable progress of corrosion can be confirmed. Compared with Example 1, BT-250 has weaker anticorrosion performance than N-acetyl-L-cysteine, and the required anticorrosion performance is not satisfied.

In Comparative Example 4, the component (A) is not included, and the component (C): citric acid is included at 15% by mass. Although component (D): N-acetyl-L-cysteine is contained, the result of immersion for 30 minutes shown in Table 3 is represented by x, and as shown in the result of FIG. The progress of corrosion can be confirmed.
That is, it can be seen that the component (D): N-acetyl-L-cysteine has insufficient anticorrosion performance under an acidic environment and exhibits sufficient anticorrosion performance under an alkaline environment.

  From the above results, it is clear that by using the cleaning liquid of the present invention, the Cu wiring can be cleaned without causing corrosion, and the excellent cleaning effect of the semiconductor device substrate is exhibited by preventing the Cu wiring surface from being corroded. It is clear that

  The substrate cleaning solution for a semiconductor device of the present invention can be cleaned without causing corrosion on the surface of the substrate for a semiconductor device and has good water rinsing properties. Therefore, in the manufacturing process of a semiconductor device, a display device, etc. This is industrially very useful as a cleaning technology for contaminated semiconductor device substrates.

Claims (7)

And also contains the following components (A) ~ respectively below a predetermined amount (E), p H is der 10 or more is, and the weight ratio of the components (C) to component (D) is (C) / (D ) = 1 / 1-2 / 1 range near the semiconductor device wafer cleaning solution, characterized in Rukoto.
(A) Organic quaternary ammonium hydroxide represented by general formula (1) : 1 to 25% by mass
(R ¹ ) ₄ N ⁺ OH ⁻ (1)
(However, R ¹ represents a hydroxyl group, an alkoxy group, or an alkyl group which may be substituted with halogen, and all four R ^{1 s} may be the same or different from each other.)
(B) Surfactant : 0.01 to 10% by mass
(C) At least one chelating agent selected from the group consisting of oxalic acid, citric acid, tartaric acid, malic acid, lactic acid, picolinic acid, ascorbic acid, gallic acid and acetic acid : 0.01 to 10% by mass
(D) An amino acid having at least one sulfur atom selected from the group consisting of N-acetyl-L-cysteine, cysteine and methionine : 0.1 to 10% by mass
(E) Water The substrate cleaning solution for a semiconductor device according to claim 1, wherein component (C) is citric acid or picolinic acid, and component (D) is cysteine or N-acetyl-L-cysteine. The component (B) is an anionic surfactant, and the substrate cleaning liquid for a semiconductor device according to claim 1 or 2 . Component (B) was selected from the group consisting of alkyl sulfonic acids and salts thereof, alkyl benzene sulfonic acids and salts thereof, alkyl diphenyl ether disulfonic acids and salts thereof, alkyl methyl tauric acids and salts thereof, and sulfosuccinic acid diesters and salts thereof. The substrate cleaning liquid for a semiconductor device according to claim 3 , wherein the substrate cleaning liquid is at least one kind. Component (A) is 0.01 to 2.5 mass%, Component (B) is 0.0001 to 1 mass%, Component (C) is 0.0001 to 1 mass%, and Component (D) is 0. The substrate cleaning solution for a semiconductor device according to any one of claims 1 to 4 , wherein the substrate cleaning solution is contained in a concentration of 0.001 to 1% by mass. Using the semiconductor device cleaning solution for a substrate according to any one of claims 1 to 5, a method for cleaning a substrate for a semiconductor device, which comprises cleaning a substrate for a semiconductor device. A semiconductor device substrate is a Cu wiring and a low dielectric constant insulating film on the substrate surface, and, according to claim 6, characterized in that cleaning the semiconductor device substrate after chemical mechanical polishing Cleaning method for semiconductor device substrate.