Ceramic compound removing cleaning solution, cleaning method and semiconductor wafer manufacturing method

Abstract

The present invention pertains to a cleaning liquid for removing cerium compounds on a silicon oxide film and / or a silicon nitride film, the cleaning liquid containing: a component (A) that is at least one compound selected from the group consisting of compounds represented by formula (1) and derivatives thereof, compounds represented by formula (2) and derivatives thereof, compounds represented by formula (3) and derivatives thereof, and compounds represented by formula (4) and derivatives thereof; and a component (B) that is a reducing agent. (In the formulas, R1-R12 and n are each as defined in the specification.)

Description

[Technical field]

[0001] The present invention relates to a cleaning solution for removing cerium compounds, a cleaning method, and a method for producing a semiconductor wafer. [Background technology]

[0002] Semiconductor wafers are manufactured by forming a metal film that will become the wiring and a deposition layer of an interlayer insulating film on a silicon substrate, then flattening the surface with a chemical mechanical polishing (hereinafter sometimes abbreviated as "CMP") process that uses an abrasive made of an aqueous slurry containing abrasive particles, and stacking a new layer on top of the flat surface. The microfabrication of semiconductor wafers requires highly accurate flatness in each layer, so the planarization process using CMP is extremely important.

[0003] In the semiconductor device manufacturing process, to electrically isolate elements such as transistors, an element isolation structure using STI (Shallow Trench Isolation), which is more suitable for miniaturization, is used instead of the conventional LOCOS (Local Oxidation of Silicon). In addition, ILD (Inter Layer Dielectric) is used between wiring layers. STI and ILD are made by depositing a silicon oxide film using TEOS (Tetraethyl Orthosilicate) and other materials, and then planarizing it in the CMP process.

[0004] Since a large amount of abrasive particles from the abrasive used in the CMP process and organic residues derived from organic compounds contained in the slurry are present on the surface of the semiconductor wafer after the CMP process, the semiconductor wafer after the CMP process is subjected to a cleaning process in order to remove these.

[0005] In recent years, cerium-based abrasive particles such as cerium oxide have been used in the CMP process for silicon oxide and silicon nitride films to increase the polishing speed. However, cerium-based abrasive particles form bonds with the surfaces of silicon oxide and silicon nitride films during the CMP process, making them difficult to remove in the cleaning process.

[0006] For this reason, cleaning has conventionally been performed using strong chemicals such as diluted hydrofluoric acid and sulfuric acid / hydrogen peroxide, but due to issues such as safety and waste liquid treatment, various cleaning solutions have been proposed as replacements for diluted hydrofluoric acid and sulfuric acid / hydrogen peroxide. For example, Patent Document 1 discloses a cleaning solution containing a reducing agent. Also, Patent Document 2 discloses a cleaning solution containing diphosphonic acid and hydrogen peroxide. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 11-251280 [Patent Document 2] Japanese Patent Publication No. 2004-022986 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the cleaning solution disclosed in Patent Document 1 does not contain a chelating agent, and therefore has a problem that the cerium compound is difficult to dissolve in the cleaning solution, and the cleaning solution is poor in terms of removability of the cerium compound. In addition, the cleaning solution disclosed in Patent Document 1 has a problem that it needs to be heated in order to dissolve the cerium compound in the cleaning solution.

[0009] In addition, the cleaning solution disclosed in Patent Document 2 does not contain a reducing agent, and therefore is unable to break the bond between the cerium compound and silicon oxide, resulting in a problem of poor removability of the cerium compound. In addition, the cleaning solution disclosed in Patent Document 2 contains hydrogen peroxide, which is easily decomposed in the cleaning solution, resulting in a problem of poor long-term quality stability of the cleaning solution.

[0010] The present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning liquid that is excellent in removing cerium compounds. [Means for solving the problem]

[0011] In the past, cleaning solutions containing various components have been investigated, but the present inventors have conducted extensive research and discovered a cleaning solution containing component (A) and component (B) described below, and have found that this cleaning solution has excellent removing properties for cerium compounds.

[0012] That is, the gist of the present invention is as follows. [1] A cleaning solution for removing cerium compounds on a silicon oxide film and / or a silicon nitride film, comprising the following component (A) and the following component (B): Component (A): at least one compound selected from the group consisting of a compound represented by the following general formula (1) and a derivative thereof, a compound represented by the following general formula (2) and a derivative thereof, a compound represented by the following general formula (3) and a derivative thereof, and a compound represented by the following general formula (4) and a derivative thereof. Component (B): Reducing agent

[0013] [ka]

[0014] (In the above general formula (1), R1 and R2 each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a carboxyl group, a carbonyl group, a chemical structure containing an ester bond, an amino group, a hydroxyl group, or a phosphonic acid group.)

[0015] [ka]

[0016] (In the above general formula (2), R3, R4, R5, and R6 each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a carboxyl group, a carbonyl group, a chemical structure containing an ester bond, an amino group, a hydroxyl group, or a phosphonic acid group.)

[0017] [ka]

[0018] (In the above general formula (3), R7, R8, R9, R 10 , R 11 and R 12 each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a carboxyl group, a carbonyl group, a chemical structure containing an ester bond, an amino group, a hydroxyl group, or a phosphonic acid group.

[0019] [ka]

[0020] (In the above general formula (4), n represents any integer.) [2] The cleaning solution according to [1], wherein the component (A) contains at least one selected from the group consisting of etidronic acid, alendronic acid, metaphosphoric acid, pyrophosphoric acid and polyphosphoric acid. [3] The cleaning solution described in [1], wherein the component (A) contains etidronic acid. [4] The cleaning solution according to any one of [1] to [3], wherein the component (B) contains at least one selected from the group consisting of ascorbic acid, gallic acid, phosphinic acid, glucose, oxalic acid, pyrogallol, pyrocatechol, and glyoxal. [5] The cleaning liquid according to any one of [1] to [3], wherein the component (B) contains at least one selected from the group consisting of phosphinic acid, glucose, and pyrogallol. [6] The cleaning solution according to any one of [1] to [5], further comprising the following component (C): Component (C): Water-soluble organic polymer [7] The cleaning liquid according to [6], wherein the component (C) contains at least one selected from polycarboxylic acids and salts thereof. [8] The cleaning solution according to any one of [1] to [7], further comprising the following component (D): Component (D): pH adjuster [9] The cleaning solution according to [8], wherein the component (D) contains at least one selected from ammonia and a quaternary ammonium salt.

[10] The cleaning solution according to any one of [1] to [9], which has a pH of 1 to 7.

[11] The cleaning liquid according to any one of [1] to

[10] , wherein a mass ratio of the component (A) to the component (B) is 1 to 100.

[12] The cleaning solution according to any one of [1] to

[11] , which is used for cleaning after chemical mechanical polishing.

[13] A cleaning method comprising the step of removing a cerium compound on a silicon oxide film and / or a silicon nitride film by using the cleaning solution according to any one of [1] to

[12] .

[14] A method for producing a semiconductor wafer, comprising the step of removing a cerium compound on a silicon oxide film and / or a silicon nitride film by using the cleaning solution according to any one of [1] to

[12] .

[15] The method for producing a semiconductor wafer according to

[14] , further comprising a step of performing chemical mechanical polishing using an abrasive containing a cerium compound. Effect of the Invention

[0021] The cleaning solution of the present invention is excellent in removing cerium compounds. Moreover, the cleaning method of the present invention is excellent in removing cerium compounds. Furthermore, since the method for producing a semiconductor wafer of the present invention includes a cleaning step that is excellent in removing cerium compounds, malfunctions of semiconductor devices can be suppressed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified and implemented in various ways within the scope of the gist. In addition, when the expression "~" is used in this specification, it is used as an expression including the numerical values ​​or physical property values ​​before and after it.

[0023] [Cleaning solution] The cleaning solution of the present invention is for removing cerium compounds and is preferably used for removing cerium compounds on a silicon oxide film and / or a silicon nitride film, and is particularly preferably used for removing cerium compounds on a silicon oxide film.

[0024] The term "cerium compound on a silicon oxide film and / or a silicon nitride film" means at least one cerium compound selected from the group consisting of cerium compounds on a silicon oxide film and cerium compounds on a silicon nitride film. Each component will be described in detail below.

[0025] (Component (A)) The cleaning solution of the present invention contains the following component (A): Component (A): at least one compound selected from the group consisting of a compound represented by the following general formula (1) and a derivative thereof, a compound represented by the following general formula (2) and a derivative thereof, a compound represented by the following general formula (3) and a derivative thereof, and a compound represented by the following general formula (4) and a derivative thereof. Component (B): Reducing agent

[0026] [ka]

[0027] (In the above general formula (1), R1 and R2 each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a carboxyl group, a carbonyl group, a chemical structure containing an ester bond, an amino group, a hydroxyl group, or a phosphonic acid group.)

[0028] [ka]

[0029] (In the above general formula (2), R3, R4, R5, and R6 each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a carboxyl group, a carbonyl group, a chemical structure containing an ester bond, an amino group, a hydroxyl group, or a phosphonic acid group.)

[0030] [ka]

[0031] (In the above general formula (3), R7, R8, R9, R 10 , R 11 and R 12 each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a carboxyl group, a carbonyl group, a chemical structure containing an ester bond, an amino group, a hydroxyl group, or a phosphonic acid group.

[0032] [ka]

[0033] (In the above general formula (4), n represents any integer.)

[0034] The cleaning solution of the present invention, containing component (A), selectively acts on cerium ions and can cut the bonds between the cerium compound and silicon oxide without damaging silicon oxide films or silicon nitride films, and is therefore excellent in terms of removing cerium compounds and causing less damage to silicon oxide films or silicon nitride films.

[0035] Among component (A), the compounds represented by general formula (1) and general formula (4) are preferred because they form a 6-membered ring complex with a cerium compound and improve the removal ability of the cerium compound, and the compound represented by general formula (1) is more preferred because it is not hydrolyzed and has improved stability.

[0036] In the general formulas (1) to (3), examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group.

[0037] Examples of the substituent that the alkyl group may have include a hydroxyl group, a carboxyl group, a carbonyl group, and an amino group.

[0038] In the general formulas (1) to (3), examples of the chemical structure containing an ester bond include sulfate ester and phosphate ester.

[0039] In general formula (1), R1 and R2 are preferably each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, or a hydroxyl group, because this facilitates the synthesis of the compound represented by general formula (1); more preferably each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 2 carbon atoms, or a hydroxyl group, because this facilitates the solubility of the compound represented by general formula (1) in water; and further preferably a combination of a methyl group and a hydroxyl group.

[0040] In general formula (2), R3, R4, R5, and R6 are preferably each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, or a hydroxyl group, because this facilitates the synthesis of the compound represented by general formula (2); more preferably each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 2 carbon atoms, or a hydroxyl group, because this facilitates the solubility of the compound represented by general formula (2) in water; and further preferably a combination of a methyl group and a hydroxyl group.

[0041] In the general formula (3), R7, R8, R9, R 10 , R 11 and R 12are preferably each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, or a hydroxyl group, because this facilitates the synthesis of the compound represented by general formula (3); are more preferably each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 2 carbon atoms, or a hydroxyl group, because this facilitates the solubility of the compound represented by general formula (3) in water; and are further preferably a combination of a methyl group and a hydroxyl group.

[0042] In the general formula (4), n is preferably 2 to 10,000, and more preferably 10 to 2,000. When n is 2 or more, the removability of the cerium compound is improved by the chelating action, and the dispersion stability is improved. When n is 10,000 or less, hydrolysis of the compound represented by the general formula (4) is suppressed.

[0043] Specific examples of the component (A) include, for example, etidronic acid, alendronic acid, metaphosphoric acid, pyrophosphoric acid, polyphosphoric acid, etc. These components (A) may be used alone or in combination of two or more.

[0044] Among these components (A), etidronic acid, pyrophosphoric acid, and polyphosphoric acid are preferred because they are easily soluble in acidic conditions, form a six-membered ring complex with a cerium compound, and improve the removability of the cerium compound. Etidronic acid and polyphosphoric acid are more preferred because they improve dispersion stability. Etidronic acid is even more preferred because it is not hydrolyzed, and therefore has improved stability.

[0045] (Component (B)) The cleaning solution of the present invention contains the following component (B): Component (B): Reducing agent

[0046] The cleaning solution of the present invention, containing component (B), selectively acts on cerium ions and can cut the bond between the cerium compound and silicon oxide without damaging the silicon oxide film or silicon nitride film, thereby improving the removability of the cerium compound and reducing damage to the silicon oxide film or silicon nitride film.

[0047] Specifically, tetravalent cerium ions are bonded to silicon oxides, and by reducing the tetravalent cerium ions to trivalent cerium ions with component (B), the bonding strength between the cerium compounds and silicon oxides is weakened, improving the removability of the cerium compounds.

[0048] Examples of component (B) include ascorbic acid (L-ascorbic acid, D-ascorbic acid, isoascorbic acid), gallic acid (anhydrous gallic acid, gallic acid monohydrate), methyl gallate, phosphinic acid, glucose, oxalic acid, hydrazine, hydroxylamine, thiourea dioxide, sodium hydrosulfite, pyrogallol, pyrocatechol, glyoxal, etc. These components (B) may be used alone or in combination of two or more.

[0049] Among these components (B), ascorbic acid, gallic acid, phosphinic acid, glucose, oxalic acid, pyrogallol, pyrocatechol, and glyoxal are preferred because of their excellent reducing power, L-ascorbic acid, gallic acid, phosphinic acid, glucose, and pyrogallol are more preferred, L-ascorbic acid, phosphinic acid, glucose, and pyrogallol are even more preferred, and phosphinic acid, glucose, and pyrogallol are particularly preferred.

[0050] (Component (C)) The cleaning liquid of the present invention preferably further contains the following component (C), since this disperses the cerium compound and improves the removability of the cerium compound. Component (C): Water-soluble organic polymer

[0051] Examples of the component (C) include polycarboxylic acids and salts of polycarboxylic acids. Examples of the polycarboxylic acids include polyacrylic acid and polymethacrylic acid. Examples of the salts of polycarboxylic acids include salts of polyacrylic acid and salts of polymethacrylic acid. These components (C) may be used alone or in combination of two or more.

[0052] Among these components (C), polycarboxylic acids and salts of polycarboxylic acids are preferred, and polyacrylic acid and salts of polyacrylic acid are more preferred, since they are easily soluble in an acidic aqueous solution.

[0053] The polycarboxylic acid may be a homopolymer of a carboxylic acid-containing monomer, or a copolymer of a carboxylic acid-containing monomer and another monomer.

[0054] The weight average molecular weight of component (C) is preferably 100 to 20,000, more preferably 200 to 10,000. When the weight average molecular weight of component (C) is 100 or more, the cerium compound is dispersed, and the removal property of the cerium compound is improved. When the weight average molecular weight of component (C) is 20,000 or less, it is easily dissolved in water.

[0055] (Component (D)) The cleaning solution of the present invention preferably further contains the following component (D) since the pH of the cleaning solution can be adjusted. Component (D): pH adjuster

[0056] Examples of component (D) include acids and alkalis. Among these components (D), alkalis are preferred because they can adjust the acid dissociation degree of component (C) and disperse the cerium compound, and ammonia and quaternary ammonium salts are more preferred, and ammonia is even more preferred, because they do not contain metal components.

[0057] (Component (E)) The cleaning liquid of the present invention preferably further contains the following component (E) since this improves the ability to remove fine particles. Component (E): Water

[0058] Examples of water include ion-exchanged water, distilled water, and ultrapure water. Among these, ultrapure water is preferred from the viewpoint of further enhancing the removability of cerium compounds.

[0059] (Other ingredients) The cleaning liquid of the present invention may contain components other than components (A) to (E) as long as the effects of the present invention are not impaired. Examples of other components include chelating agents other than component (A), surfactants, etching inhibitors, and the like.

[0060] (Properties of cleaning solution) The pH of the cleaning solution is preferably 1 to 7, more preferably 1.5 to 6, and even more preferably 2 to 5. When the pH of the cleaning solution is 1 or more, damage to components such as brushes used in the cleaning process of semiconductor wafers, etc. can be suppressed. Furthermore, when the pH of the cleaning solution is 7 or less, the removability of cerium compounds is significantly improved due to the synergistic effect of the chelating effect of component (A) and the reducing effect of component (B).

[0061] (Mass ratio of each component) The mass ratio of component (A) to component (B) (mass of component (A) / mass of component (B)) is preferably 0.1 to 100, more preferably 1 to 100, and even more preferably 1 to 10. When the mass ratio of component (A) to component (B) is 0.1 or more, the chelating effect improves the removability of cerium compounds and reduces damage to silicon oxide films and silicon nitride films. When the mass ratio of component (A) to component (B) is 100 or less, the reduction effect improves the removability of cerium compounds and reduces damage to silicon oxide films and silicon nitride films.

[0062] When the cleaning solution of the present invention contains component (C), the mass ratio of component (C) to component (A) (mass of component (C) / mass of component (A)) is preferably 0.05 to 20, more preferably 0.1 to 10, and even more preferably 0.2 to 5. When the mass ratio of component (C) to component (A) is 0.05 or more, the removability of cerium compounds is improved due to a dispersion effect. When the mass ratio of component (C) to component (A) is 20 or less, the removability of cerium compounds and the reduction of damage to silicon oxide films and silicon nitride films are improved due to a chelating effect.

[0063] When the cleaning solution of the present invention contains component (C), the mass ratio of component (C) to component (B) (mass of component (C) / mass of component (B)) is preferably 0.1 to 100, more preferably 1 to 100, and even more preferably 1 to 10. When the mass ratio of component (C) to component (B) is 0.1 or more, the removability of cerium compounds is improved due to a dispersion effect. When the mass ratio of component (C) to component (B) is 100 or less, the removability of cerium compounds and the reduction of damage to silicon oxide films and silicon nitride films are improved due to a reduction effect.

[0064] (Content of each component in the cleaning solution) The content of component (A) is preferably 0.001% by mass to 30% by mass, more preferably 0.005% by mass to 20% by mass, and even more preferably 0.01% by mass to 1% by mass, based on 100% by mass of the cleaning solution. When the content of component (A) is 0.001% by mass or more, the chelating effect improves the removability of cerium compounds and reduces damage to silicon oxide films and silicon nitride films. When the content of component (A) is 30% by mass or less, in the case where the cleaning solution contains component (E), component (A) can be sufficiently dissolved in component (E), and the production cost of the cleaning solution can be reduced.

[0065] The content of component (B) is preferably 0.0001 mass% to 30 mass%, more preferably 0.0005 mass% to 20 mass%, and even more preferably 0.001 mass% to 1 mass% in 100 mass% of the cleaning solution. When the content of component (B) is 0.0001 mass% or more, the removability of cerium compounds and the reduction of damage to silicon oxide films and silicon nitride films are improved due to the reduction effect. When the content of component (B) is 30 mass% or less, in the case where the cleaning solution contains component (E), component (B) can be sufficiently dissolved in component (E), and the production cost of the cleaning solution can be reduced.

[0066] When the cleaning solution of the present invention contains component (C), the content of component (C) is preferably 0.001% by mass to 30% by mass, more preferably 0.005% by mass to 20% by mass, and even more preferably 0.01% by mass to 1% by mass, based on 100% by mass of the cleaning solution. When the content of component (C) is 0.001% by mass or more, the removability of cerium compounds is improved due to the dispersion effect. When the content of component (C) is 30% by mass or less, when the cleaning solution contains component (E), component (C) can be sufficiently dissolved in component (E), and the production cost of the cleaning solution can be reduced.

[0067] When the cleaning solution of the present invention contains component (D), the content of component (D) is preferably 0.001% by mass to 30% by mass, more preferably 0.005% by mass to 20% by mass, and even more preferably 0.01% by mass to 1% by mass, based on 100% by mass of the cleaning solution. When the content of component (D) is 0.001% by mass or more, the pH of the cleaning solution can be easily adjusted. When the content of component (D) is 30% by mass or less, the pH of the cleaning solution can be adjusted without impairing the effects of the present invention.

[0068] When the cleaning solution of the present invention contains other components, the content of the other components is preferably 20% by mass or less, more preferably 0.0001% by mass to 10% by mass, and even more preferably 0.001% by mass to 1% by mass, based on 100% by mass of the cleaning solution. When the content of the other components is 20% by mass or less, the effects of the other components can be imparted without impairing the effects of the present invention.

[0069] When the cleaning liquid of the present invention contains component (E), the content of component (E) is preferably the balance of components other than component (E) (components (A) to (D) and other components).

[0070] (Method of manufacturing cleaning solution) The method for producing the cleaning solution of the present invention is not particularly limited, and the solution can be produced by mixing component (A), component (B), and, as necessary, components (C) to (E) and other components. The order of mixing is not particularly limited, and all of the components may be mixed at once, or some of the components may be mixed in advance and then the remaining components may be mixed.

[0071] In the method for producing the cleaning solution of the present invention, the components may be blended so as to obtain a content suitable for cleaning. However, in order to reduce costs for transportation, storage, etc., a cleaning solution containing high contents of components other than component (E) may be prepared, and then the cleaning solution may be prepared by diluting the same with component (E) before cleaning.

[0072] The dilution ratio can be appropriately set depending on the object to be washed, but is preferably 30 to 150 times, and more preferably 40 to 120 times.

[0073] (To be cleaned) Examples of objects to be cleaned with the cleaning solution of the present invention include semiconductor wafers, glass, metals, ceramics, resins, magnetic bodies, superconductors, etc. Among these objects to be cleaned, objects having a surface on which a silicon oxide film or a silicon nitride film is exposed are preferred, since the effects of the present invention are significantly improved, semiconductor wafers having a surface on which a silicon oxide film or a silicon nitride film is exposed are more preferred, and semiconductor wafers having a surface on which a silicon oxide film is exposed are even more preferred.

[0074] On the surface of a semiconductor wafer having an exposed surface of a silicon oxide film or silicon nitride film, metal may coexist in addition to silicon oxide or silicon nitride.

[0075] (Type of cleaning process) The cleaning solution of the present invention is excellent in removing cerium compounds, and therefore can be suitably used for cleaning after chemical mechanical polishing.

[0076] The chemical mechanical polishing (CMP) process is a process in which the surface of a semiconductor wafer is mechanically processed and flattened. Normally, the CMP process uses a dedicated device to attach the back surface of the semiconductor wafer to a fixture called a platen, press the surface of the semiconductor wafer against a polishing pad, and pour an abrasive containing abrasive particles onto the polishing pad to polish the surface of the semiconductor wafer.

[0077] (CMP) CMP is performed by rubbing an object to be polished against a polishing pad using an abrasive. The abrasive is not particularly limited as long as it is insoluble in water and can polish the object to be polished. However, abrasive particles are preferred, and abrasive particles of a cerium compound are more preferred, as they can fully exert the effects of the cleaning liquid of the present invention.

[0078] The abrasive particles may contain colloidal silica (SiO2), fumed silica (SiO2), or alumina (Al2O3) in addition to the abrasive particles of a cerium compound.

[0079] Examples of the cerium compound include cerium oxide and cerium hydroxide. These cerium compounds may be used alone or in combination of two or more. Among these cerium compounds, cerium oxide and cerium hydroxide are preferred, and cerium oxide is more preferred, because they are excellent in polishing speed and low scratch resistance.

[0080] In addition to the abrasive particles, the abrasive may contain additives such as oxidizers and dispersants. In particular, in the CMP of semiconductor wafers with exposed metal surfaces, anticorrosive agents are often included because metals are easily corroded.

[0081] When the cleaning solution of the present invention is applied to a semiconductor wafer having a surface on which a silicon oxide film or silicon nitride film is exposed after polishing with an abrasive containing such abrasive particles of a cerium compound, it can extremely effectively remove contamination of the semiconductor wafer originating from the cerium compound.

[0082] (Washing conditions) The method for cleaning the object to be cleaned is preferably a method in which the cleaning solution of the present invention is brought into direct contact with the object to be cleaned. Examples of methods for directly contacting the cleaning solution of the present invention with the object to be cleaned include a dip type in which a cleaning tank is filled with the cleaning solution of the present invention and the object to be cleaned is immersed in the cleaning solution, a spin type in which the object to be cleaned is rotated at high speed while the cleaning solution of the present invention is poured onto the object from a nozzle, and a spray type in which the cleaning solution of the present invention is sprayed onto the object to be cleaned, etc. Among these methods, the spin type and spray type are preferred because they allow more efficient decontamination in a short time.

[0083] Examples of equipment for performing such cleaning include a batch type cleaning equipment that simultaneously cleans a plurality of cleaning targets housed in a cassette, a single wafer type cleaning equipment that cleans a single cleaning target mounted on a holder, etc. Among these equipment, a single wafer type cleaning equipment is preferred because it can shorten the cleaning time and reduce the use of the cleaning solution of the present invention.

[0084] As for the cleaning method for the object to be cleaned, a cleaning method using a physical force is preferred, as this further improves the ability to remove contamination caused by fine particles adhering to the object to be cleaned and shortens the cleaning time. Scrub cleaning using a cleaning brush and ultrasonic cleaning with a frequency of 0.5 megahertz or more are more preferred, and scrub cleaning using a resin brush is even more preferred, as this is more suitable for cleaning after CMP.

[0085] The material of the resin brush is not particularly limited, but polyvinyl alcohol and polyvinyl formal are preferred because the resin brush itself is easy to manufacture.

[0086] The cleaning temperature may be room temperature, or may be raised to 30 to 70° C. within a range that does not impair the performance of the semiconductor wafer.

[0087] [Cleaning method] The cleaning method of the present invention is a method including a step of removing a cerium compound on a silicon oxide film and / or a silicon nitride film using the cleaning solution of the present invention, as described above.

[0088] [Method of manufacturing semiconductor wafers] The method for producing a semiconductor wafer of the present invention includes a step of removing a cerium compound on a silicon oxide film and / or a silicon nitride film using the cleaning solution of the present invention, and preferably includes a step of performing chemical mechanical polishing using an abrasive containing a cerium compound. EXAMPLES

[0089] The present invention will be described in more detail below using examples. However, the present invention is not limited to the description of the following examples as long as it does not deviate from the gist of the present invention.

[0090] (raw materials) Ingredient (A-1): Etidronic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Component (A-2): Polyphosphate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Ingredient (A'-1): Citric acid (manufactured by Showa Kako Co., Ltd.) Ingredient (B-1): Ascorbic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Ingredient (B-2): Gallic acid monohydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Component (B-3): Phosphinic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Ingredient (B-4): Glucose (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0091] Component (C-1): Polyacrylic acid (Sigma-Aldrich, weight average molecular weight approximately 2,000) Component (C-2): Polyacrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., weight average molecular weight approximately 5,000) Ingredient (E-1): Water

[0092] (pH measurement) The cleaning solutions obtained in the examples and comparative examples were each measured for pH using a pH meter (model name "D-74", manufactured by Horiba, Ltd.) while being stirred using a magnetic stirrer.

[0093] (Measurement of residual cerium oxide) A silicon substrate on which a silicon oxide film was formed by plasma CVD (Chemical Vapor Deposition) using tetraethoxysilane (TEOS) was cut into a size of 30 mm x 30 mm. The silicon substrate was then subjected to chemical mechanical polishing (CMP) for 30 seconds using an abrasive containing cerium oxide (aqueous dispersion of cerium oxide particles with a particle size of 200 nm or less) and a polishing pad (product name "IC1000", manufactured by Nitta Haas Corporation).

[0094] Next, the silicon substrate was placed in the cleaning solution obtained in the Examples and Comparative Examples and immersed for 5 minutes. The silicon substrate was then rinsed with water, dried, and the amount of cerium oxide remaining on the surface of the silicon substrate (μg / cm) was measured using an X-ray fluorescence analyzer (model name "ZSX100e", manufactured by Rigaku Corporation). 2 ) was measured.

[0095] [Example 1] A cleaning liquid was obtained by mixing the components so that, based on 100 mass% of the cleaning liquid, the component (A-1) was 0.10 mass%, the component (B-1) was 0.09 mass%, and the remainder was component (E-1). The evaluation results of the obtained cleaning solutions are shown in Table 1.

[0096] [Examples 2 to 10, Comparative Examples 1 to 8] A cleaning solution was obtained in the same manner as in Example 1, except that the types and contents of the raw materials were as shown in Table 1. The evaluation results of the obtained cleaning solutions are shown in Table 1.

[0097] [Table 1]

[0098] As can be seen from Table 1, the cleaning solutions obtained in Examples 1 to 10, which contained both component (A) and component (B), were excellent in removing cerium oxide.

[0099] On the other hand, the cleaning solutions obtained in Comparative Examples 1 to 8, which did not contain either the component (A) or the component (B), were inferior in removing cerium oxide.

[0100] Although the present invention has been described in detail and with reference to specific embodiments, it is apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2019-218699) filed on December 3, 2019, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0101] The cleaning solution of the present invention is excellent in removing cerium compounds from a silicon oxide film and / or a silicon nitride film, and therefore can be suitably used for cleaning after chemical mechanical polishing.

Claims

1. The composition includes the following component (A) and the following component (B), The mass ratio of the component (A) to the component (B) is 1 to 100; A cleaning solution for removing cerium compounds on a silicon oxide film and / or a silicon nitride film. Component (A): At least one compound selected from the group consisting of a compound represented by the following general formula (1) and a derivative thereof, a compound represented by the following general formula (2) and a derivative thereof, a compound represented by the following general formula (3) and a derivative thereof, and a compound represented by the following general formula (4) and a derivative thereof. Component (B): Reducing agent 【Chemistry 1】 (In the above general formula (1), R １ and R ２ each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a carboxyl group, a carbonyl group, a chemical structure containing an ester bond, an amino group, a hydroxyl group, or a phosphonic acid group. 【Chemistry 2】 (In the above general formula (2), R ３ , R ４ , R ５ and R ６ each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a carboxyl group, a carbonyl group, a chemical structure containing an ester bond, an amino group, a hydroxyl group, or a phosphonic acid group. 【Chemistry 3】 (In the above general formula (3), R ７ , R ８ , R ９ , R １０ , R １１ and R １２ each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, a carboxyl group, a carbonyl group, a chemical structure containing an ester bond, an amino group, a hydroxyl group, or a phosphonic acid group. 【Chemistry 4】 (In the above general formula (4), n represents any integer.)

2. 2. The cleaning solution according to claim 1, wherein the component (A) comprises at least one member selected from the group consisting of etidronic acid, alendronic acid, metaphosphoric acid, pyrophosphoric acid and polyphosphoric acid.

3. 2. The cleaning solution of claim 1, wherein said component (A) comprises etidronic acid.

4. The cleaning solution according to any one of claims 1 to 3, wherein the component (B) comprises at least one selected from the group consisting of ascorbic acid, gallic acid, phosphinic acid, glucose, oxalic acid, pyrogallol, pyrocatechol, and glyoxal.

5. The cleaning solution according to any one of claims 1 to 3, wherein the component (B) comprises at least one selected from the group consisting of phosphinic acid, glucose, and pyrogallol.

6. The cleaning solution according to any one of claims 1 to 5, further comprising the following component (C): Component (C): Water-soluble organic polymer

7. The cleaning solution according to claim 6 , wherein the component (C) comprises at least one selected from the group consisting of polycarboxylic acids and salts thereof.

8. The cleaning solution according to any one of claims 1 to 7, further comprising the following component (D): Component (D): pH adjuster

9. The cleaning solution according to claim 8 , wherein the component (D) comprises at least one selected from ammonia and a quaternary ammonium salt.

10. The cleaning solution according to any one of claims 1 to 9, which has a pH of 1 to 7.

11. The cleaning solution according to any one of claims 1 to 10, which is used for cleaning after chemical mechanical polishing.

12. A cleaning method comprising the step of removing a cerium compound on a silicon oxide film and / or a silicon nitride film by using the cleaning solution according to any one of claims 1 to 11.

13. A method for manufacturing a semiconductor wafer, comprising a step of removing a cerium compound on a silicon oxide film and / or a silicon nitride film by using the cleaning solution according to any one of claims 1 to 11.

14. The method for producing a semiconductor wafer according to claim 13, further comprising the step of performing chemical mechanical polishing using an abrasive containing a cerium compound.

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