Cleaning liquid, cleaning method, and method for manufacturing semiconductor wafer

Abstract

The present invention relates to a cleaning liquid, comprising component (A): a compound represented by the following general formula (1), component (B): an alkylamine, component (C): a polycarboxylic acid, and component (D): ascorbic acid, wherein the mass ratio of component (A) to the total mass of component (B) and component (C) is 1 to 15. (In the general formula (1), R 1 , R 2 , R 3 The definitions are the same as those in the specification. ).

Description

Technical Field

[0001] The present invention relates to a cleaning liquid, a cleaning method, and a method for manufacturing a semiconductor wafer. Background Art

[0002] Semiconductor wafers are manufactured as follows: After forming a stacked layer of metal films or interlayer insulating films that become wiring on a silicon substrate, a surface flattening process is performed using a chemical mechanical polishing (Chemical Mechanical Polishing, hereinafter sometimes referred to as "CMP") process using an abrasive formed by an aqueous slurry containing abrasive particles, and a new layer is deposited on the flat surface to manufacture semiconductor wafers. In the micro-fabrication of semiconductor wafers, high-precision flatness must be maintained in each layer, and the importance of flattening using CMP is very high.

[0003] In recent semiconductor device manufacturing processes, copper wiring formed of a copper film having a low resistance value has been introduced in order to achieve higher speed and higher integration of devices.

[0004] Copper has good processability and is therefore suitable for microfabrication. On the other hand, copper is easily corroded by acid components or alkali components, so oxidation or corrosion of copper wiring has become a problem in the CMP process.

[0005] Since a large amount of particles of colloidal silica and the like used in the CMP process and organic residues from the anticorrosive contained in the slurry exist on the surface of the semiconductor wafer after the CMP process, the semiconductor wafer after the CMP process is subjected to a cleaning process to remove these components.

[0006] In the cleaning process in the semiconductor device manufacturing process, such as the cleaning process after the CMP process, many cleaning processes using a cleaning liquid are adopted. For example, Patent Documents 1 to 6 disclose cleaning liquids used in the cleaning process in the semiconductor device manufacturing process.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2016-178118

[0010] Patent Document 2: Japanese Patent Application Publication No. 2015-165561

[0011] Patent Document 3: Japanese Patent Application No. 2003-536258

[0012] Patent Document 4: Japanese Patent Application No. 2004-518819

[0013] Patent Document 5: Japanese Patent Application Publication No. 2015-203047

[0014] Patent Document 6: Japanese Patent Application Publication No. 2015-165562 Summary of the invention

[0015] Problems to be solved by the invention

[0016] In addition, when the cleaning solution after the CMP process is an acidic aqueous solution, the colloidal silica is positively charged in the aqueous solution, and the surface of the semiconductor wafer is negatively charged, and electric attraction acts, which has a problem of difficulty in removing the colloidal silica. On the other hand, when the cleaning solution after the CMP process is an alkaline aqueous solution, since there are abundant hydroxide ions in the aqueous solution, both the colloidal silica and the surface of the semiconductor wafer are negatively charged, and electric repulsion acts, making it easy to remove the colloidal silica.

[0017] In addition, copper is present in acidic aqueous solution as copper ions (Cu 2+ ) is dissolved in an aqueous solution in the form of. On the other hand, copper forms a passivation film of copper oxide (Cu2O or CuO) on the surface of the semiconductor wafer in an alkaline aqueous solution. Based on this principle, when copper is exposed on the surface of the semiconductor wafer after the CMP process, it is considered that the use of an alkaline aqueous solution cleaning solution will reduce the corrosion of copper on the semiconductor wafer in the cleaning process after the CMP process, compared with the use of an acidic aqueous solution cleaning solution.

[0018] Since the cleaning liquids disclosed in Patent Documents 1 and 2 do not contain ascorbic acid, the corrosion inhibition effect on copper or a compound containing copper is poor.

[0019] Furthermore, since the cleaning solutions disclosed in Patent Documents 3 and 4 do not contain histidine, they are inferior in the ability to remove organic residues.

[0020] Furthermore, the cleaning solutions disclosed in Patent Documents 5 and 6 are insufficient in the selection of the types of the mixed components and the setting of the mixing ratio of histidine to other components, and thus have poor corrosion inhibition effects on copper or copper-containing compounds and poor organic residue removal performance.

[0021] The present invention is completed in view of such a problem, and an object of the present invention is to provide a cleaning solution that can inhibit the corrosion of copper or a compound containing copper and has excellent organic residue removal properties. In addition, another object of the present invention is to provide a cleaning method that can inhibit the corrosion of copper or a compound containing copper and has excellent organic residue removal properties.

[0022] Means of solving problems

[0023] Cleaning solutions containing various components have been studied in the past. The present inventors have repeatedly conducted in-depth studies and, as a result, have found a cleaning solution comprising components (A) to (D) described below. They have further found that there is an appropriate range for the ratio of the mass of component (A) to the total mass of component (B) and component (C). They have found that the cleaning solution has excellent corrosion inhibition effect on copper or a compound containing copper and excellent organic residue removal performance.

[0024] That is, the gist of the present invention is as follows <1> ~ <13> .

[0025] <1> A cleaning liquid comprising the following components (A) to (D), wherein the ratio of the mass of the component (A) to the total mass of the component (B) and the component (C) is 1 to 15.

[0026] Component (A): a compound represented by the following general formula (1):

[0027] [Chemistry 1]

[0028]

[0029] (In the above general formula (1), R 1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R 2 represents a carboxyl group, a carbonyl group, a functional group having an ester bond, a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms, R 3 represents an acetyl group, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. )

[0030] Ingredient (B): Alkylamine

[0031] Ingredient (C): Polycarboxylic acid

[0032] Ingredient (D): Ascorbic Acid

[0033] <2> like <1> The cleaning solution, wherein the ratio of the mass of the component (C) to the mass of the component (B) is 1 to 15.

[0034] <3> like <1> or <2> The cleaning solution, wherein the component (A) comprises at least one selected from the group consisting of histidine and histidine derivatives.

[0035] <4> like <1> ~ <3> The cleaning liquid described above, wherein the component (B) contains an alkyldiamine.

[0036] <5> like <4> The cleaning liquid, wherein the alkyl diamine comprises at least one selected from the group consisting of 1,2-diaminopropane, 1,3-diaminopropane and N-methyl-1,3-diaminopropane.

[0037] <6> like <1> ~ <5> The cleaning solution described in any one of the preceding claims, wherein the component (C) comprises at least one selected from the group consisting of citric acid and derivatives of citric acid.

[0038] <7> like <1> ~ <6> The cleaning solution described above further comprises the following component (E).

[0039] Ingredient (E): Quaternary ammonium hydroxide

[0040] <8> like <1> ~ <7> The cleaning solution described above further comprises the following component (F).

[0041] Ingredients (F): Water

[0042] <9> like <1> ~ <8> The cleaning solution described above has a pH of 10.0 to 14.0.

[0043] <10> like <1> ~ <9> The cleaning solution described in any one of the above is used for cleaning after chemical mechanical polishing or cleaning after etching.

[0044] <11> like <1> ~ <10> The cleaning solution described in any one of the above is used for cleaning a surface where copper or a compound containing copper is exposed.

[0045] <12> A cleaning method comprising using <1> ~ <11> A step of cleaning a semiconductor wafer using any one of the cleaning solutions.

[0046] <13> A method for manufacturing a semiconductor wafer, comprising using <1> ~ <11> A step of cleaning a semiconductor wafer using any one of the cleaning solutions.

[0047] Effects of the Invention

[0048] The cleaning liquid of the present invention can suppress the corrosion of copper or a compound containing copper and has excellent organic residue removal performance.

[0049] In addition, the cleaning method of the present invention can suppress the corrosion of copper or a compound containing copper and is excellent in the ability to remove organic residues.

[0050] Furthermore, the method for manufacturing a semiconductor wafer of the present invention includes a cleaning step that can suppress corrosion of copper or a compound containing copper and has excellent organic residue removal performance, and thus can suppress malfunction of semiconductor devices. DETAILED DESCRIPTION

[0051] The present invention is described in detail below, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist to implement the present invention. It should be noted that when the expression "to" is used in this specification, it is used in a manner that includes the numerical values ​​or physical property values ​​before and after it.

[0052] [Cleaning fluid]

[0053] The cleaning liquid of the present invention contains the following components (A) to (D).

[0054] Component (A): a compound represented by the general formula (1) described below

[0055] Ingredient (B): Alkylamine

[0056] Ingredient (C): Polycarboxylic acid

[0057] Ingredient (D): Ascorbic Acid

[0058] (ingredient (A))

[0059] Component (A) is a compound represented by the following general formula (1).

[0060] [Chemistry 2]

[0061]

[0062] In the above general formula (1), R 1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R 2 represents a carboxyl group, a carbonyl group, a functional group having an ester bond, a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms, R 3 It represents an acetyl group, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0063] The cleaning liquid of the present invention contains component (A), and the amino group and imidazole group in the structure of component (A) coordinate with metal ions to replenish the metal ions in the insoluble metal complex such as copper-benzotriazole complex and promote its dissolution in the cleaning liquid, so it is excellent in removing organic residues.

[0064] In the above general formula (1), R 1 It represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0065] In the present invention, examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl.

[0066] Due to its excellent organic residue removal performance, R 1 A hydrogen atom and a methyl group are preferred, and a hydrogen atom is more preferred.

[0067] In the above general formula (1), R2 It represents a carboxyl group, a carbonyl group, a functional group having an ester bond, a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms.

[0068] Examples of the functional group having an ester bond include a methyl ester group and an ethyl ester group.

[0069] Due to its excellent organic residue removal performance, R 2 A carboxyl group and an alkyl group having 1 to 4 carbon atoms are preferred, and a carboxyl group is more preferred.

[0070] In the above general formula (1), R 3 represents an acetyl group, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 3 A hydrogen atom and an alkyl group having 1 to 4 carbon atoms are preferred, and a hydrogen atom is more preferred.

[0071] Specific examples of component (A) include histidine such as L-histidine and D-histidine; histidine derivatives such as N-acetyl-L-histidine, etc. These components (A) can be used alone or in combination of two or more. Among these components (A), histidine is preferred, and L-histidine is more preferred, due to its excellent ability to remove organic residues.

[0072] (Component (B))

[0073] Component (B) is an alkylamine.

[0074] The alkylamine is a compound having at least an alkyl group and an amino group in the molecule. The alkyl group preferably has 1 to 6 carbon atoms, more preferably 2 to 4 carbon atoms, and even more preferably 3 carbon atoms, because of excellent organic residue removal performance.

[0075] The cleaning liquid of the present invention contains component (B), and the amino group in the structure of component (B) coordinates with metal ions to replenish metal ions in insoluble metal complexes such as copper-benzotriazole complexes and promote their dissolution in the cleaning liquid, thereby having excellent organic residue removal performance.

[0076] Specific examples of component (B) include alkyl monoamines such as aminomethane and aminoethane; alkyl diamines such as 1,2-diaminoethane, 1,2-diaminopropane, 1,3-diaminopropane, 2-methyl-1,3-diaminopropane, N-methyl-1,3-diaminopropane, and 1,4-diaminobutane. These components (B) can be used alone or in combination of two or more. Among these components (B), alkyl diamines are preferred due to their excellent organic residue removal properties, 1,2-diaminopropane, 1,3-diaminopropane, and N-methyl-1,3-diaminopropane are more preferred, and 1,2-diaminopropane is further preferred.

[0077] (ingredient (C))

[0078] Component (C) is a polycarboxylic acid.

[0079] The polycarboxylic acid refers to a compound having at least two carboxyl groups in the molecule.

[0080] The cleaning liquid of the present invention contains component (C), and the carboxyl group in the structure of component (C) coordinates with metal ions to replenish metal ions in insoluble metal complexes such as copper-benzotriazole complexes and promote their dissolution in the cleaning liquid, thereby having excellent organic residue removal performance.

[0081] The number of carboxyl groups in the molecule of component (C) is preferably 2 to 10, more preferably 2 to 6, further preferably 3 to 4, particularly preferably 3, because of excellent organic residue removability.

[0082] For excellent organic residue removability, component (C) preferably has hydroxyl groups in the molecule. For excellent organic residue removability, the number of hydroxyl groups in the molecule of component (C) is preferably 1 to 8, more preferably 1 to 4, further preferably 1 to 2, and particularly preferably 1.

[0083] As specific examples of component (C), for example, oxalic acid, citric acid, tartaric acid, malic acid, succinic acid, glutaric acid, adipic acid, malonic acid, and derivatives thereof can be cited. One of these components (C) can be used alone, or two or more thereof can be used in combination. Among these components (C), oxalic acid, citric acid, tartaric acid, malic acid, and derivatives thereof are preferred, citric acid, malic acid, and derivatives thereof are more preferred, and citric acid and citric acid derivatives are further preferred due to their excellent organic residue removal properties.

[0084] (ingredient (D))

[0085] Ingredient (D) is ascorbic acid.

[0086] The cleaning liquid of the present invention contains the component (D), so that the oxidation-reduction potential in the cleaning liquid can be lowered, thereby suppressing the oxidation of metals such as copper.

[0087] Specific examples of component (D) include L-ascorbic acid, D-ascorbic acid, isoascorbic acid, etc. These components (D) can be used alone or in combination of two or more. Among these components (D), L-ascorbic acid and D-ascorbic acid are preferred, and L-ascorbic acid is more preferred, due to their excellent corrosion inhibition effect on copper or compounds containing copper.

[0088] (Ingredient (E))

[0089] The cleaning liquid of the present invention preferably contains the following component (E) in addition to the components (A) to (D) in order to adjust the pH without leaving residue on the semiconductor wafer after cleaning.

[0090] Ingredient (E): Quaternary ammonium hydroxide

[0091] As a specific example of component (E), for example, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, triethylmethylammonium hydroxide, diethyl (dimethyl) ammonium hydroxide, diethyl (methyl) propyl ammonium hydroxide, hydroxyethyl trimethylammonium hydroxide, methyl triethanolammonium hydroxide, etc. can be cited. These components (E) can be used alone or in combination of two or more. Among these components (E), tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide are preferred for excellent storage stability, tetramethylammonium hydroxide and tetraethylammonium hydroxide are more preferred, and tetraethylammonium hydroxide is further preferred.

[0092] (ingredient (F))

[0093] The cleaning liquid of the present invention preferably contains the following component (F) in addition to the components (A) to (D) because of excellent microparticle removability.

[0094] Ingredients (F): Water

[0095] (Other ingredients)

[0096] The cleaning liquid of the present invention may contain other components other than the component (A) to the component (F) within a range that does not impair the effects of the present invention.

[0097] Examples of other components include surfactants and etching inhibitors.

[0098] Components (A) to (E) and other components may be in the form of salts.

[0099] Examples of the salt include sodium salt, potassium salt, calcium salt, and magnesium salt.

[0100] (Physical properties of cleaning fluid)

[0101] The pH of the cleaning solution is preferably 10.0 to 14.0, more preferably 10.5 to 13.0, and further preferably 11.0 to 12.0. When the pH is 10.0 or more, the corrosion of copper or a compound containing copper can be suppressed, and the organic residue removal property is excellent. In addition, when the pH is 14.0 or less, the type of the mixing components of the cleaning solution and the degree of freedom in setting the mixing ratio are high, the content of the component (E) in the cleaning solution can be reduced, and the raw material cost of the cleaning solution can be reduced.

[0102] (Redox potential of cleaning fluid)

[0103] The oxidation-reduction potential of the cleaning solution is preferably -600 mV to 0 mV, more preferably -350 mV to -50 mV, because the copper surface after cleaning can be covered with a thicker copper oxide (Cu2O) and the stability of the copper surface after cleaning is excellent.

[0104] (Mass ratio of ingredients)

[0105] In the cleaning solution of the present invention, the mass ratio of the chelating components (A) to (C) is within a specific range, and the effect of the present invention is remarkably excellent. Specifically, the mass ratio of the component (A) to the total mass of the components (B) and (C) is 1 to 15.

[0106] The ratio of the mass of component (A) to the total mass of component (B) and component (C) (mass of component (A) / total mass of component (B) and component (C)) is 1 to 15, preferably 1.1 to 5, and more preferably 1.2 to 2.2. When the ratio of the mass of component (A) to the total mass of component (B) and component (C) is 1 or more, the organic residue removability is excellent. In addition, when the ratio of the mass of component (A) to the total mass of component (B) and component (C) is 15 or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0107] The mass ratio of component (A) to component (B) (mass of component (A) / mass of component (B)) is preferably 3 to 60, more preferably 4 to 30. When the mass ratio of component (A) to component (B) is 3 or more, the organic residue removability is excellent. In addition, when the mass ratio of component (A) to component (B) is 60 or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0108] The mass ratio of component (A) to component (C) (mass of component (A) / mass of component (C)) is preferably 1.5 to 20, more preferably 2 to 6. When the mass ratio of component (A) to component (C) is 1.5 or more, the organic residue removability is excellent. In addition, when the mass ratio of component (A) to component (C) is 20 or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0109] The mass ratio of component (A) to component (D) (mass of component (A) / mass of component (D)) is preferably 0.1 to 10, more preferably 0.2 to 5. When the mass ratio of component (A) to component (D) is 0.1 or more, the organic residue removability is excellent. In addition, when the mass ratio of component (A) to component (D) is 10 or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0110] The mass ratio of the component (C) to the component (B) (mass of the component (C) / mass of the component (B)) is preferably 1 to 15, more preferably 2 to 12. When the mass ratio of the component (C) to the component (B) is 1 or more, the organic residue removability is excellent. In addition, when the mass ratio of the component (C) to the component (B) is 15 or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0111] The mass ratio of component (B) to component (D) (mass of component (B) / mass of component (D)) is preferably 0.02 to 0.4, more preferably 0.04 to 0.3. When the mass ratio of component (B) to component (D) is 0.02 or more, the organic residue removability is excellent. In addition, when the mass ratio of component (B) to component (D) is 0.4 or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0112] The mass ratio of component (C) to component (D) (mass of component (C) / mass of component (D)) is preferably 0.05 to 0.7, more preferably 0.02 to 0.5. When the mass ratio of component (C) to component (D) is 0.05 or more, the organic residue removability is excellent. In addition, when the mass ratio of component (C) to component (D) is 0.7 or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0113] When the cleaning liquid contains component (E), the ratio of the mass of component (A) to the mass of component (E) (mass of component (A) / mass of component (E)) is preferably 0.02 to 2, more preferably 0.05 to 1. When the ratio of the mass of component (A) to the mass of component (E) is 0.02 or more, the organic residue removability is excellent. In addition, when the ratio of the mass of component (A) to the mass of component (E) is 2 or less, the pH of the cleaning liquid can be easily adjusted.

[0114] When the cleaning liquid contains component (E), the ratio of the mass of component (B) to the mass of component (E) (mass of component (B) / mass of component (E)) is preferably 0.001 to 0.1, and more preferably 0.002 to 0.05. When the ratio of the mass of component (B) to the mass of component (E) is 0.001 or more, the organic residue removability is excellent. In addition, when the ratio of the mass of component (B) to the mass of component (E) is 0.1 or less, the pH of the cleaning liquid can be easily adjusted.

[0115] When the cleaning liquid contains component (E), the ratio of the mass of component (C) to the mass of component (E) (mass of component (C) / mass of component (E)) is preferably 0.005 to 0.5, more preferably 0.01 to 0.2. When the ratio of the mass of component (C) to the mass of component (E) is 0.005 or more, the organic residue removability is excellent. In addition, when the ratio of the mass of component (C) to the mass of component (E) is 0.5 or less, the pH of the cleaning liquid can be easily adjusted.

[0116] When the cleaning liquid contains component (E), the ratio of the mass of component (D) to the mass of component (E) (mass of component (D) / mass of component (E)) is preferably 0.02 to 2, more preferably 0.05 to 1. When the ratio of the mass of component (D) to the mass of component (E) is 0.02 or more, the corrosion inhibition effect on copper or a compound containing copper is excellent. In addition, when the ratio of the mass of component (D) to the mass of component (E) is 2 or less, the pH of the cleaning liquid can be easily adjusted.

[0117] (Content in cleaning fluid)

[0118] The content of component (A) is preferably 0.001% to 10% by mass, more preferably 0.005% to 1% by mass, and further preferably 0.01% to 0.1% by mass in 100% by mass of the cleaning solution. When the content of component (A) is 0.001% by mass or more, the organic residue removal property is excellent. In addition, when the content of component (A) is 10% by mass or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0119] The content of component (B) is preferably 0.0001% to 1% by mass, more preferably 0.0003% to 0.1% by mass, and further preferably 0.0005% to 0.02% by mass in 100% by mass of the cleaning solution. When the content of component (B) is 0.0001% by mass or more, the organic residue removability is excellent. In addition, when the content of component (B) is 1% by mass or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0120] The content of component (C) is preferably 0.0005% to 5% by mass, more preferably 0.002% to 0.5% by mass, and further preferably 0.005% to 0.05% by mass in 100% by mass of the cleaning solution. When the content of component (C) is 0.0005% by mass or more, the organic residue removability is excellent. In addition, when the content of component (C) is 5% by mass or less, the corrosion inhibition effect on copper or a compound containing copper is excellent.

[0121] The content of component (D) is preferably 0.001% to 10% by mass, more preferably 0.005% to 1% by mass, and further preferably 0.01% to 0.1% by mass in 100% by mass of the cleaning solution. When the content of component (D) is 0.001% by mass or more, the corrosion inhibition effect on copper or a compound containing copper is excellent. In addition, when the content of component (D) is 10% by mass or less, the pH of the cleaning solution can be easily adjusted.

[0122] When the cleaning liquid contains component (E), the content of component (E) is preferably 0.01% to 30% by mass, more preferably 0.03% to 5% by mass, and further preferably 0.05% to 0.5% by mass in 100% by mass of the cleaning liquid. When the content of component (E) is 0.01% by mass or more, the pH of the cleaning liquid can be easily adjusted. In addition, when the content of component (E) is 30% by mass or less, the pH can be adjusted without damaging the effect of the present invention.

[0123] When the cleaning liquid contains other components other than component (A) to component (F), the content of the other components is preferably 1% by mass or less, more preferably 0% by mass to 0.1% by mass, and further preferably 0% by mass to 0.01% by mass in 100% by mass of the cleaning liquid. When the content of the other components is 1% by mass or less, the effects of the other components can be imparted without impairing the effects of the present invention.

[0124] When the cleaning liquid contains the component (F), the content of the component (F) is preferably the remainder of the components other than the component (F) (the components (A) to (E) and other components).

[0125] (Method for producing cleaning fluid)

[0126] The method for producing the cleaning liquid of the present invention is not particularly limited, and the cleaning liquid can be produced by mixing the components (A) to (D) and, if necessary, the components (E) to (F) with other components.

[0127] The order of mixing is not particularly limited, and all components may be mixed at once, or some components may be mixed in advance and the remaining components may be mixed later.

[0128] The method for producing a cleaning solution of the present invention can mix the components in a manner to achieve a content suitable for cleaning. In order to reduce the costs of transportation, storage, etc., a cleaning solution containing components other than component (F) at high content can be prepared, and then the cleaning solution can be prepared by diluting it with component (F) before cleaning.

[0129] The dilution ratio can be appropriately set according to the cleaning object, and is preferably 30 to 100 times, and more preferably 40 to 90 times.

[0130] (Cleaning object)

[0131] As the cleaning object of the cleaning liquid of the present invention, for example, semiconductor wafers such as semiconductors, glass, metals, ceramics, resins, magnetic bodies, and superconductors can be cited. Among these cleaning objects, semiconductor wafers having a metal exposed surface are preferred because organic residues and particles can be removed by cleaning in a short time.

[0132] Examples of the metal include tungsten, copper, titanium, chromium, cobalt, zirconium, hafnium, molybdenum, ruthenium, gold, platinum, silver, compounds containing the above metals (nitrides of the above metals, oxides of the above metals, silicides of the above metals), etc. Among these metals, tungsten, copper, cobalt, ruthenium, and compounds containing the above metals are preferred because of their low resistivity and suitability for semiconductors, and copper and compounds containing copper are more preferred because of their excellent corrosion inhibition effect.

[0133] The cleaning liquid of the present invention has excellent organic residue removal properties even for a low-dielectric-constant insulating material having high hydrophobicity, and therefore can be suitably used for a semiconductor wafer having a surface on which a low-dielectric-constant insulating material is exposed.

[0134] As low dielectric constant insulating materials, for example, there can be mentioned organic polymer materials such as polyimide, BCB (benzocyclobutene), Flare (trade name, manufactured by Honeywell), and SiLK (trade name, manufactured by Dow Chemical); inorganic polymer materials such as FSG (fluorosilicate glass); and SiOC-based materials such as BLACK DIAMOND (trade name, manufactured by Applied Materials) and Aurora (trade name, manufactured by ASM, Japan).

[0135] (Type of cleaning process)

[0136] The cleaning liquid of the present invention has excellent organic residue removal performance and metal corrosion inhibition effect, and therefore can be suitably used for cleaning after chemical mechanical polishing and cleaning after etching, and is particularly suitable for cleaning after chemical mechanical polishing.

[0137] The chemical mechanical polishing (CMP) process refers to a process of flattening the surface of a semiconductor wafer by mechanical processing. In general, in the CMP process, a dedicated device is used to adsorb the back of the semiconductor wafer to a fixture called a platen, and the surface of the semiconductor wafer is pressed against a polishing pad, so that an abrasive containing abrasive particles flows onto the polishing pad to polish the surface of the semiconductor wafer.

[0138] The etching process is a process of forming a desired shape on a semiconductor wafer by making a mask from the resist formed in the lithography process and removing the target film in a pattern. Examples of the shape formed in the etching process include wiring patterns, vias for electrically connecting wiring to wiring, and grooves (trench) for separating components. Usually, the etching process is performed by a method called reactive ion etching using reactive gases such as fluorocarbons.

[0139] (CMP)

[0140] In CMP, an object to be polished is rubbed against a polishing pad using an abrasive to perform polishing.

[0141] Examples of abrasives include colloidal silica (SiO2), fumed silica (SiO2), alumina (Al2O3), cerium dioxide (CeO2), and other abrasive particles. These abrasive particles are the main cause of particle contamination of the body to be polished, but the cleaning liquid of the present invention has the function of removing particles attached to the body to be polished, dispersing them in the cleaning liquid, and preventing them from reattaching, and therefore shows a high effect in removing particle contamination.

[0142] In addition to polishing particles, the polishing slurry may contain additives such as an anticorrosive agent, an oxidant, and a dispersant. In particular, in CMP of a semiconductor wafer having a surface where copper or a compound containing copper is exposed, copper is easily corroded, so an anticorrosive agent is often contained.

[0143] As the anticorrosive agent, an azole anticorrosive agent with high anticorrosive effect is suitable. More specifically, as the anticorrosive agent containing a heterocyclic ring whose heteroatom is only a nitrogen atom, there can be mentioned diazole, triazole, and tetrazole anticorrosive agents; as the anticorrosive agent containing a heterocyclic ring containing a nitrogen atom and an oxygen atom, there can be mentioned oxazole, isoxazole, and oxadiazole anticorrosive agents; as the anticorrosive agent containing a heterocyclic ring containing a nitrogen atom and a sulfur atom, there can be mentioned thiazole, isothiazole, and thiadiazole anticorrosive agents; and so on. Among these anticorrosive agents, triazole anticorrosive agents are preferred due to their excellent anticorrosive effect, and among the triazole anticorrosive agents, benzotriazole anticorrosive agents are more preferred.

[0144] When the cleaning solution of the present invention is applied to a semiconductor wafer after grinding with an abrasive containing such an anticorrosive agent, it can effectively remove the pollution from the anticorrosive agent and has excellent effect. That is, when these anticorrosive agents are present in the abrasive, the corrosion of the copper surface can be suppressed, and on the other hand, it reacts with the copper ions dissolved during grinding to generate a large amount of insoluble precipitates. The cleaning solution of the present invention can effectively dissolve and remove such insoluble precipitates, and can improve production capacity.

[0145] (Cleaning conditions)

[0146] The cleaning of the cleaning object is preferably carried out by a method in which the cleaning solution of the present invention is brought into direct contact with the cleaning object.

[0147] As methods for bringing the cleaning liquid of the present invention into direct contact with the cleaning object, for example, there can be cited: an immersion method in which the cleaning liquid of the present invention is filled in a cleaning tank to immerse the cleaning object; a rotation method in which the cleaning liquid of the present invention flows from a nozzle onto the cleaning object while the cleaning object is rotated at high speed; a spray method in which the cleaning liquid of the present invention is sprayed onto the cleaning object to clean it; etc. Among these methods, the rotation method and the spray method are preferred because they can more effectively remove contamination in a short time.

[0148] As an apparatus for performing such cleaning, for example, there can be cited a batch cleaning apparatus for simultaneously cleaning a plurality of cleaning objects stored in a box, a single-wafer cleaning apparatus for cleaning a single cleaning object mounted on a support frame, etc. Among these apparatuses, a single-wafer cleaning apparatus is preferred because it can shorten the cleaning time and reduce the use of the cleaning solution of the present invention.

[0149] In order to further improve the removal of contamination caused by particles attached to the cleaning object and shorten the cleaning time, the cleaning method for the cleaning object is preferably cleaning using physical force, and brushing with a cleaning brush or ultrasonic cleaning with a frequency of 0.5 MHz or above is more preferred. Since it is more suitable for post-CMP cleaning, brushing with a resin brush is further preferred.

[0150] The material of the resin brush is not particularly limited, but polyvinyl alcohol and polyvinyl formal are preferred because the resin brush itself can be easily produced.

[0151] The cleaning temperature may be room temperature or may be heated to 30 to 70° C. within a range that does not impair the performance of the semiconductor wafer.

[0152] [Cleaning method]

[0153] The cleaning method of the present invention is a method including the step of cleaning a semiconductor wafer using the cleaning solution of the present invention, and the specific cleaning conditions and the like are as described above.

[0154] [Method for manufacturing semiconductor wafer]

[0155] The method for producing a semiconductor wafer of the present invention is a method including the step of cleaning a semiconductor wafer using the cleaning solution of the present invention, and the specific cleaning conditions and the like are as described above.

[0156] Example

[0157] The present invention will be described in more detail below using examples, but the present invention is not limited to the description of the following examples unless it departs from the gist of the present invention.

[0158] [Example 1]

[0159] As raw materials of the cleaning solution, the following components were prepared.

[0160] Component (A-1): L-histidine (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0161] Component (B-1): 1,2-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0162] Component (B-2): 1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0163] Component (B-3): N-methyl-1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0164] Component (B'-1): Imidazole (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0165] Component (C-1): Citric acid (manufactured by Showa Chemical Industry Co., Ltd.)

[0166] Component (C-2): Tartaric acid (manufactured by Showa Chemical Industry Co., Ltd.)

[0167] Component (C-3): Succinic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0168] Ingredient (D-1): L-ascorbic acid (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0169] Ingredient (D'-1): Gallic acid (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0170] Component (E-1): Tetraethylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0171] Ingredients (F-1): Water

[0172] The components are mixed so that, in 100 mass% of the cleaning liquid, the content of component (A-1) is 0.040 mass%, the content of component (B-1) is 0.002 mass%, the content of component (C-1) is 0.020 mass%, the content of component (D-1) is 0.040 mass%, the content of component (E-1) is 0.140 mass%, and the balance is component (F-1), thereby obtaining a cleaning liquid.

[0173] (pH determination)

[0174] The cleaning liquid obtained in Example 1 was stirred in a thermostatic bath at 25° C. using a magnetic stirrer, and the pH was measured using a pH meter (model name “D-24”, manufactured by Horiba, Ltd.).

[0175] (Corrosion inhibition effect measurement)

[0176] A silicon substrate (manufactured by ADVANTEC Co., Ltd.) on which copper was deposited with a film thickness of 1.5 μm was cut into 20 mm×20 mm, and the cut silicon substrate was immersed in 20 g of the cleaning solution obtained in Example 1 at 25° C. for 10 minutes. After the immersion, the silicon substrate was taken out, and the copper concentration in the cleaning solution was measured using an ICP emission spectrometer (model name “SPS 1700HVR”, manufactured by Seiko Instruments Co., Ltd.).

[0177] The copper corrosion rate (nm / min) was calculated from the measured copper concentration using the following mathematical formula (A) to evaluate the corrosion inhibition effect. The results are shown in Table 1. It should be noted that the smaller the value of the copper corrosion rate (nm / min), the higher the corrosion inhibition effect.

[0178] Copper corrosion rate = (copper concentration in cleaning solution × cleaning solution volume) / (copper density × surface area of ​​silicon substrate × immersion time) (A)

[0179] (Organic residue removability measurement)

[0180] For a silicon substrate (manufactured by ADVANTEC Co., Ltd.) on which copper was vapor-deposited with a film thickness of 1.5 μm, CMP was performed using an abrasive containing silicon dioxide and benzotriazole and a CMP apparatus (model name "LGP-15RD", manufactured by Lapmaster SFT Co., Ltd.), and then the surface of the silicon substrate was cleaned using a polyvinyl alcohol brush while the cleaning liquid obtained in Example 1 was supplied to the surface of the silicon substrate.

[0181] The number of defects of 0.35 μm or more on the obtained silicon substrate after CMP cleaning was measured using a wafer surface inspection device (model name “LS-6600”, manufactured by Hitachi High-tech Fielding Co., Ltd.), and the organic residue removability was evaluated.

[0182] [Examples 2 to 11, Comparative Examples 1 to 7]

[0183] The same operation as in Example 1 was carried out except that the types and contents of the raw materials were as shown in Table 1 to obtain a cleaning liquid, and the same measurements as in Example 1 were carried out. The results are shown in Table 1.

[0184]

[0185] As can be seen from Table 1, the cleaning solutions obtained in Examples 1 to 11 can suppress copper corrosion and are excellent in removing organic residues.

[0186] On the other hand, the cleaning liquid obtained in Comparative Example 1 did not contain the component (A), and therefore had poor organic residue removability.

[0187] In addition, in the cleaning liquid obtained in Comparative Example 2, the ratio of the mass of the component (A) to the total mass of the components (B) and (C) was below the lower limit, and thus the organic residue removability was poor.

[0188] In the cleaning liquid obtained in Comparative Example 3, the ratio of the mass of the component (A) to the total mass of the components (B) and (C) exceeded the upper limit value, and thus the corrosion inhibition effect on copper was poor.

[0189] In addition, since the cleaning liquid obtained in Comparative Example 4 did not contain the component (D), the corrosion suppressing effect on copper was poor.

[0190] In addition, since the cleaning liquid obtained in Comparative Example 5 contains a compound not included in the component (D), the corrosion inhibition effect on copper is poor.

[0191] In addition, the cleaning liquids obtained in Comparative Examples 6 and 7 were inferior in the ability to remove organic residues because compounds not included in the component (B) were blended.

[0192] Although the present invention is described in detail with reference to specific embodiments, it is apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention. This application is based on Japanese patent application (Japanese Patent Application No. 2018-161077) filed on August 30, 2018, and its contents are introduced into this specification by reference.

[0193] Industrial Applicability

[0194] The cleaning liquid of the present invention is excellent in the ability to remove organic residues and the effect of inhibiting metal corrosion, and therefore can be suitably used for cleaning after chemical mechanical polishing and cleaning after etching, and is particularly suitably used for cleaning after chemical mechanical polishing.

Claims

1. A cleaning solution comprising the following components (A) to (D), wherein: The ratio of the mass of the component (A) to the total mass of the components (B) and (C) is 1 to 15, Component (A): a compound represented by the following general formula (1), [Chemistry 1] In the general formula (1), R 1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R 2 represents a carboxyl group, a carbonyl group, a functional group having an ester bond, a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms, R 3 represents an acetyl group, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Component (B): alkylamine; Component (C): polycarboxylic acid; Ingredient (D): Ascorbic acid.

2. The cleaning solution according to claim 1, wherein The ratio of the mass of the component (C) to the mass of the component (B) is 1-15.

3. The cleaning solution according to claim 1 or 2, wherein The component (A) includes at least one selected from the group consisting of histidine and histidine derivatives.

4. The cleaning solution according to claim 1 or 2, wherein The ingredient (B) contains an alkyl diamine.

5. The cleaning solution according to claim 4, wherein The alkyldiamine includes at least one selected from the group consisting of 1,2-diaminopropane, 1,3-diaminopropane, and N-methyl-1,3-diaminopropane.

6. The cleaning solution according to claim 1 or 2, wherein: The component (C) includes at least one selected from the group consisting of citric acid and derivatives of citric acid.

7. The cleaning solution according to claim 1 or 2, further comprising the following component (E), Ingredient (E): quaternary ammonium hydroxide.

8. The cleaning solution according to claim 1 or 2, further comprising the following component (F), Ingredients (F): Water.

9. The cleaning solution according to claim 1 or 2, which has a pH of 10.0 to 14.

0.

10. The cleaning solution according to claim 1 or 2, which is used for cleaning after chemical mechanical polishing or cleaning after etching.

11. The cleaning solution according to claim 1 or 2, which is used for cleaning a surface where copper or a compound containing copper is exposed. 12 . A cleaning method comprising the step of cleaning a semiconductor wafer using the cleaning solution according to claim 1 . 13 . A method for producing a semiconductor wafer, comprising the step of cleaning a semiconductor wafer using the cleaning solution according to claim 1 .

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