Composition suppressing damage to aluminum oxide and method for producing semiconductor substrate using the same

Abstract

The present invention relates to a composition capable of removing dry etching residues present on the surface of a semiconductor integrated circuit while suppressing damage to aluminum oxide in the manufacturing process of a semiconductor integrated circuit, a method for cleaning a semiconductor substrate having aluminum oxide, and a method for manufacturing a semiconductor substrate having an aluminum oxide layer. The composition of the present invention is characterized in that it contains 0.00005 to 1% by mass of a barium compound (A) and 0.01 to 20% by mass of a fluorine compound (B), and the pH of the composition is in the range of 2.5 to 8.0.

Description

Technical Field

[0001] The present invention relates to a composition capable of suppressing damage to aluminum oxide and removing dry etching residues present on the surface of a semiconductor integrated circuit in a manufacturing process of the semiconductor integrated circuit, and a method for manufacturing a semiconductor substrate using the composition. Background Art

[0002] In the dry etching process of semiconductor integrated circuits, generally speaking, residues (called dry etching residues) originating from etching gas components, etched layers, mask layers (resist, hard mask, etc.), etc. are generated. If the next process is proceeded without removing the dry etching residues, the yield will decrease, so a process for removing the dry etching residues is required.

[0003] When dry etching residues are removed by oxygen plasma, materials exposed to the oxygen plasma are damaged, resulting in significant degradation of electrical properties. Therefore, a method is required that removes dry etching residues to the same extent as in the oxygen plasma process but does not damage other materials.

[0004] When dry etching is performed until cobalt, which is a wiring material, is reached, cobalt is exposed to the dry etching gas and deteriorates, which may affect the electrical characteristics. Therefore, a process is considered in which an etching stopper layer is provided on cobalt, a via hole is formed by dry etching until the etching stopper layer is reached, and then the etching stopper layer at the bottom of the via hole is removed by a method that has little effect on cobalt to expose the cobalt.

[0005] Generally speaking, fluorine-based gases are selected when forming via holes by dry etching. If aluminum oxide is selected as an etching stop layer, since aluminum oxide has high resistance to fluorine-based gases, it has the advantage that even a thin film can function as an etching stop layer (Non-Patent Document 1).

[0006] When aluminum oxide is selected as the etching stopper layer, it is necessary to suppress damage to the aluminum oxide in the step of removing the dry etching residue, and a chemical agent capable of achieving this purpose is required.

[0007] In addition, it is necessary to suppress damage not only to aluminum oxide but also to cobalt and low-dielectric-constant interlayer insulating films depending on the structure of the substrate.

[0008] In addition, hard masks used as masks during dry etching are generally made of silicon or titanium, but in recent years, there are also examples of using zirconium oxide hard masks (Non-Patent Document 2). Therefore, when a zirconium oxide hard mask is used, zirconium oxide is contained in the dry etching residue.

[0009] Prior art literature

[0010] Non-patent literature

[0011] Non-patent literature 1: 16th MME workshop, Goeteborg, Sweden, 2005 “Etch stop materials for release by vapor HF etching”

[0012] Non-patent document 2: M Padmanaban et al, J. Photopolym. Sci. Technol., 27 (2014) 503 Summary of the invention

[0013] Problem that the invention aims to solve

[0014] An object of the present invention is to provide a composition capable of suppressing damage to aluminum oxide and removing dry etching residue, and a method for producing a semiconductor substrate using the composition.

[0015] Solutions for solving problems

[0016] The present inventors have conducted intensive studies and have found that the present problems can be solved by the following invention. The present invention is as follows.

[0017] [1] A composition comprising 0.00005 to 1% by mass of a barium compound (A) and 0.01 to 20% by mass of a fluorine compound (B), wherein the pH of the composition is within a range of 2.5 to 8.0.

[0018] [2] The composition according to [1], wherein the barium compound (A) contains one or more selected from the group consisting of barium nitrate, barium acetate, barium chloride, barium hydroxide, barium sulfite, barium chlorate, barium perchlorate, barium peroxide, barium chromate, barium oxide, barium cyanide, barium bromide, barium carbonate, barium metaborate, barium iodide, barium tetrafluoroborate, barium sulfate and barium sulfide.

[0019] [3] The composition according to [1], wherein the barium compound (A) contains one or more selected from the group consisting of barium nitrate, barium acetate, barium chloride and barium hydroxide.

[0020] [4] The composition according to any one of [1] to [3], wherein the fluorine compound (B) contains hydrofluoric acid or a fluoride salt.

[0021] [5] The composition according to any one of [1] to [4], wherein the pH thereof is within the range of 3.1 to 7.4.

[0022] [6] The composition according to any one of [1] to [5], wherein the content of hydrogen peroxide is less than 0.002% by mass.

[0023] [7] The composition according to any one of [1] to [6], further comprising 0.01 to 10% by mass of a benzotriazole compound (C).

[0024] [8] The composition according to any one of [1] to [7], further comprising 0.0005 to 1% by mass of a compound (D) having a pyrrolidone structure.

[0025] [9] The composition according to any one of [1] to [8], wherein the etching rate of aluminum oxide at 50°C is / min(4.0×10 -9 m / min) or less.

[0026]

[10] The composition according to any one of [1] to [9], wherein the etching rate of cobalt at 50°C is / min(1.0×10 -10 m / min) or less.

[0027]

[11] The composition according to any one of [1] to

[10] , wherein the etching rate of the low dielectric constant interlayer insulating film at 50° C. is / min(1.0×10 -10 m / min) or less.

[0028]

[12] The composition according to any one of [1] to

[11] , which is used for removing dry etching residue of a semiconductor substrate having an aluminum oxide layer.

[0029]

[13] A method for producing a semiconductor substrate having an aluminum oxide layer, using the composition described in any one of [1] to

[12] . The production method of the present invention includes a step of removing dry etching residue using the composition described in any one of [1] to

[12] .

[0030]

[14] A method for cleaning a semiconductor substrate having an aluminum oxide layer, comprising the step of removing dry etching residue using the composition according to any one of [1] to

[12] .

[0031] Effects of the Invention

[0032] According to a preferred embodiment of the present invention, by using the composition of the present invention, dry etching residues on the surface of the workpiece can be removed while suppressing damage to aluminum oxide in the manufacturing process of semiconductor circuits, and high-precision, high-quality semiconductor substrates can be manufactured with good yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1The schematic cross-sectional view of one embodiment of a semiconductor substrate having a structure of a low dielectric constant interlayer insulating film, cobalt or a cobalt alloy, aluminum oxide, and a titanium-based hard mask in a semiconductor substrate before removing dry etching residue when the bottom of a via hole is aluminum oxide.

[0034] Figure 2 The present invention is a schematic cross-sectional view of a semiconductor substrate having a structure of a low dielectric constant interlayer insulating film, cobalt or cobalt alloy, aluminum oxide, and a titanium-based hard mask in a semiconductor substrate before removing dry etching residue when the bottom of a via hole is cobalt or cobalt alloy.

[0035] Figure 3 The schematic cross-sectional view of one embodiment of a semiconductor substrate having a structure of a low dielectric constant interlayer insulating film, cobalt or cobalt alloy, aluminum oxide, and a zirconium oxide-based hard mask in a semiconductor substrate before removing dry etching residue when the bottom of a via hole is aluminum oxide.

[0036] Figure 4 The present invention is a schematic cross-sectional view of a semiconductor substrate having a structure of a low dielectric constant interlayer insulating film, cobalt or cobalt alloy, aluminum oxide, and a zirconium oxide-based hard mask in a semiconductor substrate before removing dry etching residue when the bottom of a via hole is cobalt or a cobalt alloy. DETAILED DESCRIPTION

[0037] The composition of the present invention contains a barium compound (A) and a fluorine compound (B), which will be described in detail below.

[0038] [Barium compound (A)]

[0039] The barium compound (A) of the present application is an inorganic substance containing barium and has an effect of preventing aluminum oxide from corroding.

[0040] Specific examples of the barium compound (A) include barium nitrate, barium acetate, barium chloride, barium hydroxide, barium sulfite, barium chlorate, barium perchlorate, barium peroxide, barium chromate, barium oxide, barium cyanide, barium bromide, barium carbonate, barium metaborate, barium iodide, barium tetrafluoroborate, barium sulfate, barium sulfide, and salts formed by the reaction of barium hydroxide with an acid. These can be used alone or in combination of two or more.

[0041] Among them, barium nitrate, barium acetate, barium chloride, and barium hydroxide are preferred because they have high water solubility and are easily available.

[0042] The concentration (content) of the barium compound (A) in the composition is 0.00005 to 1 mass %, preferably 0.00025 to 0.75 mass %, more preferably 0.001 to 0.1 mass %, particularly preferably 0.004 to 0.06 mass %. Within this range, damage to alumina can be effectively suppressed.

[0043] [Fluorine compound (B)]

[0044] The fluorine compound (B) in the present invention is a compound containing fluorine atoms (but excluding compounds having a carbon-fluorine (CF) bond), and specific examples include hydrofluoric acid, fluoride salts, tetrafluoroboric acid, tetrafluoroborate, hexafluorosilicic acid, hexafluorosilicate, hexafluorophosphoric acid and hexafluorophosphate.

[0045] Here, the fluoride salt is not particularly limited as long as it is a salt of hydrofluoric acid and an inorganic base or an organic base. As specific examples of the fluoride salt, preferably ammonium fluoride, lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, beryllium fluoride, magnesium fluoride, calcium fluoride, strontium fluoride, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride and tetrabutylammonium fluoride are listed.

[0046] The fluorine compound (B) has the effect of removing dry etching residues. Among them, hydrofluoric acid and fluoride salts are preferred, which have high dry etching residue removal properties and are easily available. In addition, they can be used alone or in combination of two or more.

[0047] The concentration (content) of the fluorine compound (B) in the composition is 0.01 to 20 mass %, preferably 0.02 to 17.5 mass %, more preferably 0.03 to 15.0 mass %, particularly preferably 0.05 to 10.0 mass %. Within this range, damage to alumina can be effectively suppressed.

[0048] [Benzotriazole compound (C)]

[0049] In the present invention, a benzotriazole compound (C) may be added to improve the corrosion resistance to cobalt or cobalt alloys.

[0050] The benzotriazole compound (C) refers to a compound having a benzotriazole skeleton, and specific examples thereof include benzotriazole, 5-methyl-1H-benzotriazole, and 2,2'-[[(methyl-1H-benzotriazole-1-yl)methyl]imino]diethanol. In addition, any compound having a benzotriazole skeleton may also be used. These may be used alone or in combination of two or more.

[0051] When a benzotriazole compound (C) is used, the concentration (content) of the benzotriazole compound (C) in the composition is usually 0.01 to 10% by mass, preferably 0.025 to 7.5% by mass, more preferably 0.05 to 5.0% by mass, and particularly preferably 0.1 to 1.0% by mass. By being within this range, damage to cobalt or cobalt alloys can be effectively suppressed.

[0052] [Compound having a pyrrolidone structure (D)]

[0053] In the present invention, in order to improve the corrosion resistance to the low dielectric constant interlayer insulating film and cobalt or cobalt alloy, a compound (D) having a pyrrolidone structure may be added.

[0054] The compound (D) having a pyrrolidone structure used in the present invention refers to an oligomer or polymer whose repeating unit contains a pyrrolidone unit, specifically, polyvinylpyrrolidone, a random copolymer containing a pyrrolidone unit, an alternating copolymer containing a pyrrolidone unit, a block copolymer containing a pyrrolidone unit, and a branched polymer containing a pyrrolidone unit.

[0055] The weight average molecular weight of the compound (D) having a pyrrolidone structure is usually 1000 to 5000000, preferably 1300 to 3500000, more preferably 1600 to 2800000, and particularly preferably 2000 to 1200000, and the ratio of the pyrrolidone unit in the compound (D) having a pyrrolidone structure to the repeating unit is usually 50% or more, preferably 60% or more, more preferably 65% ​​or more, and particularly preferably 70% or more. By being within these ranges, damage to the low dielectric constant interlayer insulating film and cobalt or cobalt alloy can be effectively suppressed.

[0056] As the compound (D) having a pyrrolidone structure, for example, PITZCOL (trademark) series manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. are available and can be preferably used.

[0057] When a compound (D) having a pyrrolidone structure is used, the concentration (content) of the compound (D) having a pyrrolidone structure in the composition is generally 0.0005 to 1% by mass, preferably 0.001 to 0.75% by mass, more preferably 0.002 to 0.5% by mass, and particularly preferably 0.003 to 0.1% by mass. If it is within the above range, damage to the low dielectric constant interlayer insulating film and cobalt or cobalt alloy can be effectively suppressed.

[0058] [Other ingredients]

[0059] The composition of the present invention may contain components conventionally used in semiconductor compositions as needed within a range that does not impair the purpose of the present invention.

[0060] For example, diethylene glycol monobutyl ether may be added as a solvent, and an alkali, an acid, a chelating agent, a surfactant, a defoaming agent, an oxidizing agent, a reducing agent, a metal anticorrosive agent, a water-soluble organic solvent, etc. may be added as an additive.

[0061] [water]

[0062] The remainder of the composition of the present invention is water. The water that can be used in the present invention is not particularly limited, but is preferably water obtained by removing metal ions, organic impurities, particles, etc. by distillation, ion exchange treatment, filter treatment, various adsorption treatments, etc., more preferably pure water, and particularly preferably ultrapure water.

[0063] The concentration (content) of water in the composition is preferably 45 to 100% by mass, more preferably 90 to 100% by mass, and further preferably 95 to 100% by mass.

[0064] [Method for producing composition]

[0065] The composition of the present invention is produced by adding water (preferably ultrapure water) to the barium compound (A), the fluorine compound (B) and other components as required, and stirring until the mixture becomes uniform.

[0066] The pH of the composition is in the range of 2.5 to 8.0, preferably 2.7 to 7.8, more preferably 2.9 to 7.6, and particularly preferably 3.1 to 7.4. It should be noted that the pH is preferably less than 7.0, and more preferably 3.1 to 6.5. When the pH is within this range, damage to cobalt or cobalt alloy, aluminum oxide, low dielectric constant interlayer insulating film, and silicon nitride can be effectively suppressed while removing dry etching residue.

[0067] It should be noted that the composition of the present invention preferably contains substantially no hydrogen peroxide, and more preferably the concentration (content) of hydrogen peroxide in the composition is less than 0.002% by mass.

[0068] [How to use the composition]

[0069] The temperature for using the composition of the present invention is usually 20 to 70° C., preferably 30 to 60° C., and particularly preferably 40 to 55° C. The temperature may be appropriately selected depending on the dry etching conditions and the structure of the semiconductor substrate used.

[0070] The time for using the composition of the present invention is usually 0.2 to 60 minutes, and may be appropriately selected depending on the dry etching conditions and the structure of the semiconductor substrate used.

[0071] The composition of the present invention can be used, for example, in contact with the surface of a semiconductor substrate. According to a preferred embodiment of the present invention, by contacting the composition of the present invention with the surface of a semiconductor substrate, dry etching residues can be removed from the surface of the semiconductor substrate. According to a particularly preferred embodiment of the present invention, when the semiconductor substrate has an aluminum oxide layer containing aluminum oxide, dry etching residues can be removed from the surface of the semiconductor substrate while suppressing damage to the aluminum oxide contained in the aluminum oxide layer.

[0072] There is no particular limitation on the method for contacting the surface of the semiconductor substrate with the composition of the present invention, and for example, a method of contacting the surface of the semiconductor substrate with the composition of the present invention in the form of dropwise addition (single-sheet rotation processing) or spraying, or a method of immersing the semiconductor substrate in the composition of the present invention, etc. In the present invention, any method can be used.

[0073] As the rinsing liquid after using the composition of the present invention, either an organic solvent or water can be used.

[0074] [Semiconductor substrate]

[0075] As a semiconductor substrate to which the composition of the present invention can be preferably used,

[0076] Substrate materials such as silicon, amorphous silicon, polycrystalline silicon, and glass;

[0077] Insulating materials such as silicon oxide, silicon nitride, silicon carbide and their derivatives;

[0078] Cobalt, cobalt alloy, tungsten, titanium-tungsten and other materials;

[0079] Compound semiconductors such as gallium-arsenic, gallium-phosphorus, indium-phosphorus, indium-gallium-arsenic, indium-aluminum-arsenic, and oxide semiconductors such as chromium oxide, especially substrates of low dielectric constant interlayer insulating films, semiconductor substrates having any of these materials preferably have an aluminum oxide layer containing aluminum oxide. Specifically, for example, the aluminum oxide layer is provided as an etching stopper layer.

[0080] The content of aluminum oxide in the aluminum oxide layer is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 70% by mass or more, further more preferably 90% by mass or more, particularly preferably 100% by mass.

[0081] The dry etching residue to be removed in the present invention includes, for example, residues generated when a via hole or a trench is formed in a low dielectric constant interlayer insulating film by dry etching using a titanium-based or zirconium-oxide-based hard mask as a mask. In this case, a part of the dry etching residue is generated by the contact of the etching gas with the titanium-based hard mask or the zirconium-oxide-based hard mask. Therefore, the dry etching residue to be removed usually contains titanium or zirconium.

[0082] The composition of the present invention can preferably sufficiently suppress damage to aluminum oxide in the step of removing dry etching residue. For example, when the semiconductor substrate is immersed in the composition of the present invention and the etching rate of aluminum oxide is measured at 50°C, it is preferably / min(4.0×10 -9 m / min) or less, preferably / min(3.5×10 -9 m / min) or less, more preferably / min(3.3×10 -9 m / min) or less, particularly preferably / min(1.5×10 -9 m / min) or less.

[0083] In one aspect of the present invention, when the semiconductor substrate has cobalt or a cobalt alloy in addition to aluminum oxide and further has a low dielectric constant interlayer insulating film, it is more preferable to suppress damage to these.

[0084] For example, when the semiconductor substrate is immersed in the composition of the present invention and the etching rate of cobalt is measured at 50° C., it is preferably / min(5.0×10 -10 m / min) or less, preferably / min(3.0×10 -10 m / min) or less, more preferably / min(1.0×10 -10 m / min) or less, and more preferably / min(0.5×10 -10 m / min) or less, particularly preferably / min(0.3×10 -10 m / min) or less.

[0085] In addition, when the semiconductor substrate is immersed in the composition of the present invention and measured at 50° C., the etching rate of the low dielectric constant interlayer insulating film is / min(5.0×10 -10 m / min) or less, preferably / min(3.0×10 -10 m / min) or less, more preferably / min(1.0×10 -10 m / min), further preferably / min(0.5×10 -10 m / min) or less, particularly preferably / min(0.2×10 -10 m / min) or less.

[0086] [Method for producing a semiconductor substrate having an aluminum oxide layer]

[0087] The method for manufacturing a semiconductor substrate of the present invention includes a step of removing dry etching residues using the composition of the present invention. For example, it includes a step of contacting a semiconductor substrate having an aluminum oxide layer with the composition of the present invention after forming a via hole or a trench by dry etching and before removing the dry etching residues, thereby removing the dry etching residues from the surface of the semiconductor substrate.

[0088] The use temperature and use time of the composition of the present invention are as described in the aforementioned "Method of Using the Composition". For the semiconductor substrate having an aluminum oxide layer, it is as described in the aforementioned "Semiconductor Substrate". There is no particular limitation on the method of contacting the surface of the semiconductor substrate having an aluminum oxide layer with the composition of the present invention. For example, a method of contacting the surface of the semiconductor substrate with the composition of the present invention by dripping (single-sheet rotation processing) or spraying, or a method of immersing the semiconductor substrate in the composition of the present invention, etc. can be adopted. In the present invention, any method can be adopted.

[0089] Figures 1 to 4 An example of a cross-sectional structure of a semiconductor substrate having an aluminum oxide layer after forming a via hole by dry etching and before removing a dry etching residue is shown.

[0090] Figure 1 The schematic cross-sectional view of one embodiment of a semiconductor substrate having a structure of a low dielectric constant interlayer insulating film, cobalt or a cobalt alloy, aluminum oxide, and a titanium-based hard mask in a semiconductor substrate before removing dry etching residue when the bottom of a via hole is aluminum oxide. Figure 1 In the embodiment, cobalt or cobalt alloy 3 as a wiring material and aluminum oxide 4 as an etching stopper are stacked on a semiconductor substrate, and a low dielectric constant interlayer insulating film 5 and a titanium hard mask 2 are stacked thereon in sequence. The bottom of the via hole is aluminum oxide 4, and titanium dry etching residue 1 is attached to the surface of the via hole and the titanium hard mask 2.

[0091] Figure 2 The present invention is a schematic cross-sectional view of a semiconductor substrate having a structure of a low dielectric constant interlayer insulating film, cobalt or cobalt alloy, aluminum oxide, and a titanium-based hard mask in a semiconductor substrate before removing dry etching residue when the bottom of a via hole is cobalt or cobalt alloy. Figure 2 In the embodiment, cobalt or cobalt alloy 3 as a wiring material and aluminum oxide 4 as an etching stopper are stacked on a semiconductor substrate, and a low dielectric constant interlayer insulating film 5 and a titanium hard mask 2 are stacked thereon in sequence. The bottom of the via hole is cobalt or cobalt alloy 3, and titanium dry etching residue 1 is attached to the surface of the via hole and the titanium hard mask 2.

[0092] Figure 3 The schematic cross-sectional view of one embodiment of a semiconductor substrate having a structure of a low dielectric constant interlayer insulating film, cobalt or cobalt alloy, aluminum oxide, and a zirconium oxide-based hard mask in a semiconductor substrate before removing dry etching residue when the bottom of a via hole is aluminum oxide. Figure 3In the embodiment, cobalt or cobalt alloy 3 as a wiring material and aluminum oxide 4 as an etching stopper are stacked on a semiconductor substrate, and a low dielectric constant interlayer insulating film 5 and a zirconium oxide hard mask 7 are stacked thereon in order. The bottom of the via hole is aluminum oxide 4, and zirconium oxide dry etching residue 6 is attached to the surface of the via hole and the zirconium oxide hard mask 7.

[0093] Figure 4 The present invention is a schematic cross-sectional view of a semiconductor substrate having a structure of a low dielectric constant interlayer insulating film, cobalt or cobalt alloy, aluminum oxide, and a zirconium oxide-based hard mask in a semiconductor substrate before removing dry etching residue when the bottom of a via hole is cobalt or a cobalt alloy. Figure 4 In the embodiment, cobalt or cobalt alloy 3 as a wiring material and aluminum oxide 4 as an etching stopper are stacked on a semiconductor substrate, and a low dielectric constant interlayer insulating film 5 and a zirconium oxide hard mask 7 are stacked thereon in order. The bottom of the via hole is cobalt or cobalt alloy 3, and zirconium oxide dry etching residue 6 is attached to the surface of the via hole and the zirconium oxide hard mask 7.

[0094] In the method for manufacturing a semiconductor substrate of the present invention, by bringing the semiconductor substrate having an aluminum oxide layer before removing the dry etching residue into contact with the composition of the present invention, the dry etching residue can be removed from the surface of the semiconductor substrate. Thus, a semiconductor substrate can be manufactured with a good yield. According to a preferred embodiment of the present invention, damage to aluminum oxide contained in the aluminum oxide layer can be fully suppressed in the process of removing the dry etching residue. In addition, in one embodiment of the present invention, when the semiconductor substrate has cobalt or a cobalt alloy in addition to aluminum oxide, and further has a low dielectric constant interlayer insulating film, damage to them can be suppressed. Thus, a semiconductor substrate can be manufactured without affecting the electrical characteristics.

[0095] [Cleaning method for semiconductor substrate having aluminum oxide layer]

[0096] The semiconductor substrate cleaning method of the present invention includes a step of removing dry etching residues using the composition of the present invention. For example, it includes a step of contacting a semiconductor substrate having an aluminum oxide layer with the composition of the present invention after forming a via hole or a groove by dry etching and before removing the dry etching residue, thereby removing the dry etching residue from the surface of the semiconductor substrate.

[0097] The use temperature and use time of the composition of the present invention are as described in the above "Method of using the composition". The method of bringing the surface of the semiconductor substrate having an aluminum oxide layer into contact with the composition of the present invention is also as described in the above "Method of producing a semiconductor substrate having an aluminum oxide layer". In addition, the semiconductor substrate having an aluminum oxide layer to be cleaned is also as described in the above "Semiconductor substrate" and the above "Method of producing a semiconductor substrate having an aluminum oxide layer".

[0098] By using the semiconductor substrate cleaning method of the present invention, dry etching residues can be removed from the surface of the semiconductor substrate. In a preferred embodiment of the cleaning method of the present invention, damage to aluminum oxide can be fully suppressed in the process of removing dry etching residues. In addition, in one embodiment of the cleaning method of the present invention, when the semiconductor substrate has cobalt or a cobalt alloy as a wiring material and further has a low dielectric constant interlayer insulating film, damage to them can be fully suppressed. Thus, the semiconductor substrate can be manufactured without affecting the electrical characteristics.

[0099] Example

[0100] The present invention will be specifically described below using examples, but the embodiments may be modified as appropriate as long as the effects of the present invention are exhibited.

[0101] In addition, % means mass % unless otherwise specified.

[0102] [Evaluation wafer]

[0103] <Evaluation wafer A>: For evaluation of titanium (Ti) residue removal

[0104] Starting from the bottom layer, silicon nitride, an interlayer insulating film, silicon nitride, titanium oxide, and a photoresist are formed into films, and then the photoresist is patterned.

[0105] Using the photoresist as a mask, a predetermined portion of the hard mask is removed by dry etching, and the photoresist is removed by ashing using oxygen plasma. Furthermore, using the hard mask as a mask, a via hole is formed in the silicon nitride and interlayer insulating film by dry etching.

[0106] <Evaluation Wafer B>: Evaluation of Zirconia (Zr) Residue Removal

[0107] Starting from the bottom layer, silicon nitride, an interlayer insulating film, silicon nitride, zirconium oxide, and a photoresist are formed into films, and then the photoresist is patterned.

[0108] Using the photoresist as a mask, a predetermined portion of the hard mask is removed by dry etching, and the photoresist is removed by ashing using oxygen plasma. Furthermore, using the hard mask as a mask, a via hole is formed in the silicon nitride and interlayer insulating film by dry etching.

[0109] <Wafer with film>: Damage evaluation of aluminum oxide, cobalt, and low-k interlayer insulating films using the composition

[0110] Wafers with films (a wafer with an aluminum oxide film, a wafer with a cobalt film, and a wafer with a TEOS film) formed of aluminum oxide, cobalt, and a low-dielectric interlayer insulating film (TEOS "tetraethoxysilicate") were used.

[0111] [Evaluation method]

[0112] <Residue removal evaluation>

[0113] SEM observation was performed on the evaluation wafer A and the evaluation wafer B after being treated with the various compositions.

[0114] Measurement instrument: Hitachi High-Technologies Corporation. Ultra-high resolution field emission scanning electron microscope SU9000 (magnification 100,000 times)

[0115] Determination method:

[0116] E: Dry etching residue is completely removed.

[0117] G: The dry etching residue is almost completely removed.

[0118] P: Removal of dry etching residue is insufficient.

[0119] E and G were judged as passing.

[0120] <ER(etching rate)>

[0121] Each wafer with a film was treated with a composition at 50°C, and the difference in film thickness before and after the treatment was divided by the treatment time to calculate the ER. The film thickness of the wafer with a film was measured using a fluorescent X-ray device SEA1200VX (film thickness measuring device A) manufactured by SII Nano Technology Inc., or an optical film thickness meter n&k1280 (film thickness measuring device B) manufactured by n&k Technology Inc. The film thickness of the wafer with a cobalt film was measured using the film thickness measuring device A, and the film thickness of the wafer with an aluminum oxide film and the wafer with a TEOS film was measured using the film thickness measuring device B.

[0122] For alumina, ER is / min or less is considered as qualified product

[0123] For cobalt, ER is / min or less is considered as qualified product

[0124] For TEOS, ER is / min or less is considered a qualified product.

[0125] [Examples 1 to 8 and Comparative Examples 1 to 12]

[0126] The test used evaluation wafer A, evaluation wafer B, and wafer with aluminum oxide film. They were immersed in the composition listed in Table 1 at 50°C, then rinsed with ultrapure water and dried by spraying dry nitrogen. Evaluation wafer A and evaluation wafer B were all immersed for 1 minute, and the wafers after treatment were observed by SEM.

[0127] The wafer with the aluminum oxide film was immersed for 5 minutes, and the ER was calculated from the film thickness before and after the treatment (in the comparative example, the aluminum oxide film was completely dissolved by the 5-minute immersion treatment, so the ER was calculated by 30-second immersion treatment except for Comparative Example 11).

[0128] The pH of each composition was measured at 25° C. using a pH meter (pH meter F-52 manufactured by Horiba, Ltd.).

[0129] It is found that in Examples 1 to 8, the dry etching residue was completely removed while preventing damage to aluminum oxide.

[0130] On the other hand, it is known that the comparative examples cannot be used for the purpose of suppressing the damage of aluminum oxide and removing the dry etching residue on the surface of the processed object. In particular, it is known that in comparative examples 4 to 10, compositions in which the cations are changed to Be, Mg, Ca, and Sr of the same group as barium are used, but the same effect as the barium salt is not obtained.

[0131] [Table 1]

[0132]

[0133] [Examples 9 to 13]

[0134] Evaluation was performed on the composition of Table 2 using a combination of a benzotriazole compound (C) and a compound (D) having a pyrrolidone structure. The test used evaluation wafer A, evaluation wafer B, a wafer with an aluminum oxide film, a wafer with a cobalt film, and a wafer with a TEOS film. The wafers were immersed in the composition described in Table 2 at 50°C, and then rinsed with ultrapure water and dried by spraying dry nitrogen. For evaluation wafer A and evaluation wafer B, an immersion treatment for 1 minute was performed in the same manner as in Examples 1 to 8, and the treated wafers were observed using SEM. For the wafer with an aluminum oxide film, an immersion treatment for 5 minutes was performed in the same manner as in Examples 1 to 8, and the ER was calculated. For the wafer with a cobalt film and the wafer with a TEOS film, an immersion treatment for 30 minutes was performed, respectively, and the ER was calculated. It can be seen that in Examples 9 and 10, the dry etching residue is completely removed while preventing damage to aluminum oxide and cobalt. Furthermore, it can be seen that in Examples 11 to 13, the dry etching residue is completely removed while preventing damage to aluminum oxide, cobalt, and the low-dielectric-constant interlayer insulating film.

[0135] [Table 2]

[0136]

[0137] Description of Reference Numerals

[0138] 1: Titanium dry etching residue

[0139] 2: Titanium hard mask

[0140] 3: Cobalt or cobalt alloy

[0141] 4: Alumina

[0142] 5: Low dielectric constant interlayer insulation film

[0143] 6: Zirconia-based dry etching residue

[0144] 7: Zirconia hard mask

Claims

1. A composition comprising 0.00005 to 1% by mass of a barium compound (A) and 0.01 to 20% by mass of a fluorine compound (B), wherein the pH of the composition is in the range of 2.5 to 8.0, The content of hydrogen peroxide was less than 0.002 mass %.

2. The composition according to claim 1, wherein The barium compound (A) contains one or more selected from the group consisting of barium nitrate, barium acetate, barium chloride, barium hydroxide, barium sulfite, barium chlorate, barium perchlorate, barium peroxide, barium chromate, barium oxide, barium cyanide, barium bromide, barium carbonate, barium metaborate, barium iodide, barium tetrafluoroborate, barium sulfate and barium sulfide.

3. The composition according to claim 1, wherein The barium compound (A) contains one or more selected from the group consisting of barium nitrate, barium acetate, barium chloride and barium hydroxide.

4. The composition according to any one of claims 1 to 3, wherein The fluorine compound (B) contains hydrofluoric acid or a fluoride salt. 5 . The composition according to claim 1 , wherein the pH thereof is within the range of 3.1 to 7.

4. 6 . The composition according to claim 1 , further comprising 0.01 to 10% by mass of a benzotriazole compound (C). 7 . The composition according to claim 1 , further comprising 0.0005 to 1% by mass of a compound (D) having a pyrrolidone structure.

8. The composition according to any one of claims 1 to 3, wherein The etching rate of aluminum oxide at 50°C is Below is 4.0×10 -9 m / min or less.

9. The composition according to any one of claims 1 to 3, wherein The etching rate of cobalt at 50°C is Below is 1.0×10 -10 m / min or less.

10. The composition according to any one of claims 1 to 3, wherein The etching rate of the low dielectric constant interlayer insulating film at 50°C is Below is 1.0×10 -10 m / min or less. 11 . The composition according to claim 1 , which is used for removing dry etching residues of a semiconductor substrate having an aluminum oxide layer. 12 . A method for producing a semiconductor substrate having an aluminum oxide layer, comprising the step of removing dry etching residue using the composition according to claim 1 . 13 . A method for cleaning a semiconductor substrate having an aluminum oxide layer, comprising the step of removing dry etching residue using the composition according to claim 1 .

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