Semiconductor substrate cleaning composition and cleaning method using same

Abstract

Provided is a composition for cleaning a semiconductor substrate, which contains hydrogen peroxide, a basic compound, phosphoric acid and / or a salt thereof, boric acid and / or a salt thereof, aminopolymethylenephosphonic acid, and water, and wherein the basic compound contains at least one element selected from the group consisting of quaternary ammonium hydroxide and potassium hydroxide.

Description

Technical Field

[0001] The present invention relates to a semiconductor substrate cleaning composition and a cleaning method using the same. Background Art

[0002] In the manufacture of semiconductor substrates with highly integrated semiconductor elements, a conductive film such as a metal film that serves as a raw material for conductive wiring, an interlayer insulating film for insulation between the conductive films, a hard mask, etc. are typically formed on a substrate such as a silicon wafer. A photoresist is then uniformly applied to the surface to form a photosensitive layer, which is then selectively exposed and developed to produce the desired resist pattern. Next, using the resist pattern as a mask, a dry etching process is performed on the substrate laminated with the interlayer insulating film, hard mask, etc., thereby forming the desired pattern on the substrate. Furthermore, a series of steps are typically employed to remove the photoresist pattern and the residue generated by the dry etching process (hereinafter referred to as "dry etching residue") using ashing caused by oxygen plasma, cleaning solutions, and the like.

[0003] When dry etching reaches the wiring material, the wiring material may be exposed to the dry etching gas and deteriorate, affecting its electrical properties. Therefore, the following process is considered: an etch stop layer (also called an etch stoplayer) is provided on the wiring material, a through hole is formed by dry etching to reach the etch stop layer, and then the etch stop layer at the bottom of the through hole is removed using a method that minimizes the impact on the wiring material, exposing the wiring material, and then removing the hard mask. Therefore, a chemical solution is required that can minimize damage to copper or copper alloys, cobalt or cobalt alloys, and the etch stop layer, while removing the hard mask and dry etching residue.

[0004] In recent years, the increasing miniaturization of design rules has led to an increase in the current density of metal wiring. Consequently, there is a growing demand for countermeasures against electromigration, in which atoms forming metal wiring migrate when current flows through the metal wiring material, creating gaps in the metal wiring. Among these countermeasures are methods that form a layer of cobalt or a cobalt alloy as a cover metal around copper wiring, and methods that use cobalt or a cobalt alloy as the metal wiring material. Consequently, methods have been proposed for removing hard masks in the presence of copper or a copper alloy and cobalt or a cobalt alloy during the formation of semiconductor devices on substrates such as silicon wafers.

[0005] Patent Documents 2 and 3 propose methods of removing a hard mask made of titanium nitride using an alkaline cleaning solution containing hydrogen peroxide.

[0006] When aluminum nitride is used in the etching stop layer, if a conventional alkaline semiconductor substrate cleaning composition is used to remove the hard mask formed of titanium nitride, the hard mask formed of titanium nitride is removed. Figure 1 The semiconductor substrate shown has a problem in that the etching rate of aluminum nitride is high and the etching stop layer 2 containing aluminum nitride is consumed.

[0007] Patent Document 1 discloses a cleaning composition that helps remove residues after etching in semiconductor manufacturing. The composition comprises a tetraalkylammonium hydroxide base or a quaternary trialkylalkanolamine base, a corrosion inhibitor, and a combination of at least two polybasic acids or salts thereof, wherein at least one of the polybasic acids or salts contains phosphorus.

[0008] Furthermore, Patent Document 1 utilizes phosphoric acid to suppress the etching rate of aluminum nitride, and further utilizes 5-methylbenzotriazole to reduce damage to metal wiring. However, while azole-based corrosion inhibitors such as 5-methylbenzotriazole have a high corrosion protection effect on metals, they sometimes remain on the metal surface after cleaning or degrade the removability of metal residues. Furthermore, particularly effective corrosion inhibitors such as 5-methylbenzotriazole are generally expensive. Therefore, it is desirable to avoid the use of azole-based corrosion inhibitors such as 5-methylbenzotriazole, or to minimize their use.

[0009] As compositions that do not use azole-based corrosion inhibitors, cleaning compositions containing hydrogen peroxide, potassium hydroxide, quaternary ammonium hydroxide, and aminopolymethylenephosphonic acid are proposed in Patent Documents 2 and 3. However, there is a problem in that it is difficult to simultaneously suppress the etching rates of aluminum nitride and metal wiring.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: WO2018 / 098139

[0013] Patent Document 2: WO2022 / 071069

[0014] Patent Document 3: WO2014 / 087925 Summary of the Invention

[0015] Problems to be solved by the invention

[0016] In view of the above-mentioned conventional problems, the present invention aims to provide a semiconductor substrate cleaning composition and a cleaning method using the same, wherein the semiconductor substrate cleaning composition can suppress the etching rate of aluminum nitride contained in the etch stop layer without using an azole-based corrosion inhibitor, and suppress damage to copper and / or cobalt contained in the metal wiring, and remove the hard mask layer.

[0017] Solutions for solving problems

[0018] The present inventors conducted intensive research to solve the above-mentioned problems and found that a semiconductor substrate cleaning composition can be obtained by using phosphoric acid and boric acid in combination. This semiconductor substrate cleaning composition can suppress the etching rate of aluminum nitride contained in the etch stop layer without using an azole-based corrosion inhibitor, and can also suppress damage to copper and / or cobalt contained in the metal wiring, while removing the hard mask layer. This has led to the completion of the present invention.

[0019] That is, the present invention includes the following aspects.

[0020] <1> A semiconductor substrate cleaning composition comprising hydrogen peroxide, an alkaline compound, phosphoric acid and / or its salt, boric acid and / or its salt, aminopolymethylenephosphonic acid, and water, wherein the alkaline compound comprises at least one member selected from the group consisting of quaternary ammonium hydroxide and potassium hydroxide.

[0021] <2> The semiconductor substrate cleaning composition according to <1> above, wherein the phosphoric acid salt is at least one selected from the group consisting of quaternary ammonium phosphate salts and potassium phosphate salts, and the boric acid salt is at least one selected from the group consisting of quaternary ammonium borate salts and potassium borate salts.

[0022] <3> The semiconductor substrate cleaning composition according to <1> or <2> above, wherein the content of the phosphoric acid and / or its salt is 0.05 to 2% by mass in terms of phosphoric acid in the semiconductor substrate cleaning composition, and the content of the boric acid and / or its salt is 0.1 to 4% by mass in terms of boric acid in the semiconductor substrate cleaning composition.

[0023] <4> The semiconductor substrate cleaning composition according to any one of <1> to <3> above, wherein the content of the hydrogen peroxide in the semiconductor substrate cleaning composition is 10 to 30% by mass.

[0024] <5> The semiconductor substrate cleaning composition according to any one of <1> to <4>, wherein the content of the aminopolymethylenephosphonic acid in the semiconductor substrate cleaning composition is 0.00005 to 0.01% by mass.

[0025] <6> The semiconductor substrate cleaning composition according to any one of <1> to <5> above, wherein the content of the quaternary ammonium hydroxide in the semiconductor substrate cleaning composition is 0.005 to 10% by mass.

[0026] <7> The semiconductor substrate cleaning composition according to any one of <1> to <6> above, wherein the content of the potassium hydroxide in the semiconductor substrate cleaning composition is 0.005 to 5% by mass.

[0027] <8> The semiconductor substrate cleaning composition according to any one of <1> to <7>, wherein the semiconductor substrate cleaning composition has a pH of 7 to 12.

[0028] <9> The semiconductor substrate cleaning composition according to any one of <1> to <8>, wherein the quaternary ammonium hydroxide is at least one selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and benzyltrimethylammonium hydroxide.

[0029] <10> The semiconductor substrate cleaning composition according to any one of <1> to <9> above, wherein the aminopolymethylenephosphonic acid is at least one selected from the group consisting of aminotris(methylenephosphonic acid), ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid) and 1,2-propylenediaminetetra(methylenephosphonic acid).

[0030] <11> The semiconductor substrate cleaning composition according to any one of <1> to <10>, further comprising at least one hydrogen peroxide stabilizer selected from the group consisting of oxalic acid, diethylenetriaminepentaacetic acid, hydroxyethyliminodiacetic acid, 5-phenyl-1H-tetrazole, triethylenetetraaminehexaacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, 8-hydroxyquinoline, L(+)-isoleucine, DL-valine, L(-)-proline, hydroxyethylethylenediaminetriacetic acid, N,N-bis(2-hydroxyethyl)glycine, glycine, L-tryptophan, 2,6-pyridinedicarboxylic acid, benzothiazole, and DL-alanine.

[0031] <12> The semiconductor substrate cleaning composition according to <11> above, wherein the content of the hydrogen peroxide stabilizer in the semiconductor substrate cleaning composition is 0.0001 to 5% by mass.

[0032] <13> The semiconductor substrate cleaning composition according to any one of <1> to <12>, which does not substantially contain ammonia and ammonium ions (NH4 + ).

[0033] <14> A method for cleaning a semiconductor substrate, wherein, for a semiconductor substrate having an etching stop layer comprising aluminum nitride and a hard mask layer on a metal wiring comprising copper and / or cobalt, the semiconductor substrate cleaning composition described in any one of <1> to <13> is used to remove the hard mask layer.

[0034] <15> The semiconductor substrate cleaning method according to <14>, wherein the hard mask layer includes at least one selected from the group consisting of titanium and titanium nitride.

[0035] <16> A method for manufacturing a semiconductor substrate, comprising the steps of: removing the hard mask layer from a semiconductor substrate having an etching stop layer containing aluminum nitride and a hard mask layer on a metal wiring containing copper and / or cobalt using the semiconductor substrate cleaning composition described in any one of <1> to <13> above.

[0036] Effects of the Invention

[0037] By using the semiconductor substrate cleaning composition and cleaning method of the present invention, Figure 1 The semiconductor substrate shown suppresses the etching rate of aluminum nitride included in etching stopper layer 2 (suppresses damage) and suppresses damage to copper and / or cobalt included in metal wiring 3 , and enables removal of hard mask layer 1 . BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of a cross section of a semiconductor substrate before the semiconductor substrate is cleaned with the semiconductor substrate cleaning composition.

[0039] Figure 2 This is a schematic diagram of a cross section of a semiconductor substrate after the semiconductor substrate has been cleaned using the semiconductor substrate cleaning composition. DETAILED DESCRIPTION

[0040] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below and can be arbitrarily modified and implemented without departing from the spirit of the present invention.

[0041] [Semiconductor substrate cleaning composition]

[0042] The semiconductor substrate cleaning composition of the present invention comprises hydrogen peroxide, an alkaline compound, phosphoric acid and / or its salt, boric acid and / or its salt, aminopolymethylenephosphonic acid, and water.

[0043] Hydrogen peroxide

[0044] Hydrogen peroxide is usually mixed with other components in the form of an aqueous solution of appropriate concentration. The concentration of hydrogen peroxide in the aqueous hydrogen peroxide solution used in the preparation of the semiconductor substrate cleaning composition of the present invention is not particularly limited, but is preferably, for example, 10 to 90% by mass, more preferably 30 to 60% by mass, which meets industrial standards.

[0045] In addition, hydrogen peroxide may also contain a stabilizer used during production. The method for producing hydrogen peroxide is not limited. For example, hydrogen peroxide produced by the anthraquinone method is suitable. In addition, hydrogen peroxide may be hydrogen peroxide purified by methods such as passing the solution through an ion exchange resin.

[0046] From the viewpoint of cleaning properties, the content of hydrogen peroxide in the semiconductor substrate cleaning composition is preferably 10 to 30% by mass, more preferably 10 to 20% by mass.

[0047] <Basic compounds>

[0048] The alkaline compound includes at least one member selected from the group consisting of quaternary ammonium hydroxide and potassium hydroxide. The alkaline compound effectively removes hard masks and dry etching residues, and prevents damage to low-k interlayer insulating films and metal wiring. The quaternary ammonium hydroxide and potassium hydroxide may be blended alone or in combination of two or more.

[0049] It is particularly preferred to contain both quaternary ammonium hydroxide and potassium hydroxide as the basic compound.

[0050] The quaternary ammonium hydroxide is not particularly limited, but is preferably at least one selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and benzyltrimethylammonium hydroxide. From the viewpoint of economic efficiency and easy availability of raw materials, it is more preferably at least one selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and benzyltrimethylammonium hydroxide, and tetramethylammonium hydroxide is even more preferred.

[0051] The content of the quaternary ammonium hydroxide in the semiconductor substrate cleaning composition is preferably 0.005 to 10% by mass, more preferably 0.5 to 7% by mass, and even more preferably 1 to 6% by mass.

[0052] The content of potassium hydroxide in the semiconductor substrate cleaning composition is preferably 0.005 to 5% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.1 to 1% by mass.

[0053] When the content of the basic compound is within the above range, the etching rates of titanium and titanium nitride are particularly good, which is preferable.

[0054] <Phosphoric acid and / or its salts, boric acid and / or its salts>

[0055] In the present invention, phosphoric acid and boric acid are used in combination, such as Figure 2 As shown, the etching rate of aluminum nitride contained in etching stop layer 2 can be suppressed (damage can be suppressed), and the increase in the etching rate of cobalt contained in metal wiring 3 can be suppressed, thereby suppressing damage to metal wiring 3. When only phosphoric acid is used, the etching rate of cobalt increases, but the increase in the etching rate of cobalt can be suppressed by adding boric acid.

[0056] In the present invention, phosphoric acid and boric acid are used in combination. However, it is considered that most of these compounds exist in the form of salts in the semiconductor substrate cleaning composition.

[0057] In the present invention, the salt of phosphoric acid is preferably at least one selected from the group consisting of quaternary ammonium phosphate and potassium phosphate.

[0058] On the other hand, the salt of boric acid is preferably at least one selected from the group consisting of quaternary ammonium borate salts and potassium borate salts.

[0059] The content of phosphoric acid and / or its salt in the semiconductor substrate cleaning composition is preferably 0.05 to 2 mass %, more preferably 0.1 to 1.5 mass %, and particularly preferably 0.25 to 1 mass % in terms of phosphoric acid.

[0060] The content of boric acid and / or its salt in the semiconductor substrate cleaning composition is preferably 0.1 to 4 mass %, more preferably 0.2 to 3 mass %, and particularly preferably 0.5 to 2 mass % in terms of boric acid.

[0061] <Aminopolymethylenephosphonic acid>

[0062] By containing aminopolymethylenephosphonic acid, a chelate is formed in the presence of copper ions, thereby improving the stability of hydrogen peroxide, which is preferred.

[0063] The aminopolymethylenephosphonic acid is preferably at least one selected from the group consisting of aminotri(methylenephosphonic acid), ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and 1,2-propylenediaminetetra(methylenephosphonic acid).

[0064] The content of aminopolymethylenephosphonic acid in the semiconductor substrate cleaning composition is preferably 0.00005 to 0.01 mass %, more preferably 0.0005 to 0.005 mass %, and even more preferably 0.001 to 0.004 mass %.

[0065] When the content of aminopolymethylenephosphonic acid is within the above range, the stability of hydrogen peroxide can be maintained and the cost can be suppressed.

[0066] Water

[0067] The water is not particularly limited, but is preferably water obtained by removing metal ions, organic impurities, fine particles, etc. by distillation, ion exchange treatment, filtration treatment, various adsorption treatments, etc., more preferably pure water, and particularly preferably ultrapure water.

[0068] The water content, which represents the remainder of the semiconductor substrate cleaning composition of the present invention after excluding hydrogen peroxide, alkaline compounds, phosphoric acid and / or its salts, boric acid and / or its salts, aminopolymethylenephosphonic acid, and other components, is preferably 50% by mass or greater, more preferably 72% to 89.9385% by mass, even more preferably 73% to 89.798% by mass, even more preferably 73% to 87% by mass, and particularly preferably 75% to 85% by mass. When the water content falls within this range, the effects of the present invention can be achieved while also being more economical.

[0069] <Hydrogen peroxide stabilizer>

[0070] The semiconductor substrate cleaning composition of the present invention preferably contains a hydrogen peroxide stabilizer.

[0071] The hydrogen peroxide stabilizer preferably includes at least one selected from the group consisting of oxalic acid, diethylenetriaminepentaacetic acid, hydroxyethyliminodiacetic acid, 5-phenyl-1H-tetrazole, triethylenetetraaminehexaacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, 8-hydroxyquinoline, L(+)-isoleucine, DL-valine, L(-)-proline, hydroxyethylethylenediaminetriacetic acid, N,N-bis(2-hydroxyethyl)glycine, glycine, L-tryptophan, 2,6-pyridinedicarboxylic acid, benzothiazole, and DL-alanine.

[0072] In a preferred embodiment of the present invention, the inclusion of the aforementioned hydrogen peroxide stabilizer allows for high stability of hydrogen peroxide even in the presence of multiple metals including cobalt, and allows for long-term cleaning and repeated use. In a preferred embodiment of the present invention, the inclusion of the aforementioned hydrogen peroxide stabilizer allows for high stability of hydrogen peroxide, particularly in the presence of copper and cobalt, and allows for long-term cleaning and repeated use.

[0073] When cleaning a semiconductor substrate using a semiconductor substrate cleaning composition, decomposition of hydrogen peroxide is particularly likely to occur when multiple metals including cobalt are present, particularly when both copper and cobalt are present.

[0074] In a preferred embodiment of the present invention, as mentioned above, the reason for improving the stability of hydrogen peroxide in the presence of copper and cobalt is not yet clear, but it is believed that the compound exemplified herein, due to its structure, particularly the balance of amino and carboxyl groups, even in the presence of two metals and in an alkaline solution, also shows strong chelating ability to any one of copper ion or cobalt ion, or both. In addition, even if copper ion and cobalt ion are alone, they also have a certain hydrogen peroxide decomposition ability, but as mentioned above, there is a problem that the decomposition rate becomes larger due to the simultaneous presence of copper ion and cobalt ion. It is believed that as this mechanism, in addition to the catalytic effect caused by copper ion and cobalt ion, the Fenton-like reaction is carried out due to the presence of copper ion, and the hydroxyl radical generated participates in the reaction. It is believed that in a preferred embodiment of the present invention, by having the ability to capture hydroxyl radicals on the basis of chelating ability, the stability of hydrogen peroxide is further improved.

[0075] Among hydrogen peroxide stabilizers, from the viewpoint of suppressing corrosion of metals constituting semiconductor substrates, at least one selected from the group consisting of oxalic acid, diethylenetriaminepentaacetic acid, hydroxyethyliminodiacetic acid, triethylenetetraaminehexaacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, 8-hydroxyquinoline, hydroxyethylethylenediaminetriacetic acid, 5-phenyl-1H-tetrazole, N,N-bis(2-hydroxyethyl)glycine, and benzothiazole is preferred. From the viewpoint of suppressing metal corrosion and further improving the stability of hydrogen peroxide, at least one selected from the group consisting of diethylenetriaminepentaacetic acid, hydroxyethyliminodiacetic acid, triethylenetetraaminehexaacetic acid, hydroxyethylethylenediaminetriacetic acid, and trans-1,2-cyclohexanediaminetetraacetic acid is more preferred. At least one selected from the group consisting of diethylenetriaminepentaacetic acid and trans-1,2-cyclohexanediaminetetraacetic acid is even more preferred. Trans-1,2-cyclohexanediaminetetraacetic acid is particularly preferred.

[0076] Semiconductor substrates contain metal components such as metal wiring. The hydrogen peroxide stabilizer described herein is believed to have the unique property of capturing metal ions in the solution while not ionizing the metal. This prevents corrosion of the metal wiring, stabilizes hydrogen peroxide, and improves cleaning properties. It is also believed to have the ability to capture hydroxyl radicals.

[0077] Examples of hydrogen peroxide stabilizers include the aforementioned compounds, and hydrates, salts, and derivatives of these compounds may also be used in the cleaning composition. For example, monohydrate of trans-1,2-cyclohexanediaminetetraacetic acid is preferably used from the viewpoint of availability and ease of blending.

[0078] In a preferred embodiment of the present invention, the content of the hydrogen peroxide stabilizer in the semiconductor substrate cleaning composition is preferably 0.0001 to 5% by mass, more preferably 0.001 to 1% by mass.

[0079] By adjusting the content of the hydrogen peroxide stabilizer within the aforementioned range, the semiconductor substrate cleaning composition of the present invention exhibits high stability of hydrogen peroxide in the presence of multiple metals including cobalt, particularly copper and cobalt, and allows for long-term cleaning and repeated use. Furthermore, corrosion of metals, etc., constituting semiconductor substrates, can be suppressed.

[0080] <Other ingredients>

[0081] The semiconductor substrate cleaning composition of the present invention may contain other components in addition to the aforementioned components, as long as the purpose of the present invention is not impaired. For example, a surfactant, a defoaming agent, etc. may be added.

[0082] In the semiconductor substrate cleaning composition of the present invention, ammonia and ammonium ions (NH4 + ) has the effect of increasing the corrosion of copper and cobalt, and is preferably substantially free of all. Here, "substantially free of" means not containing or containing within a range that does not impair the effects of the present invention, specifically, ammonia and ammonium ions (NH4 + The total content of ) in the semiconductor substrate cleaning composition is preferably less than 0.01 mass ppm, more preferably less than 10 mass ppm, and further preferably contains no ammonia and ammonium ions (NH4 + ).

[0083] <Characteristics of the Semiconductor Substrate Cleaning Composition>

[0084] The pH of the semiconductor substrate cleaning composition of the present invention is preferably 7 to 12, more preferably 7.5 to 11, even more preferably 8 to 10, and particularly preferably 8 to 9. By adjusting the pH within this range, the stability of hydrogen peroxide can be maintained at a high level, and cleaning properties can also be improved. The pH can be measured by the method described in the Examples.

[0085] (Semiconductor Substrate Cleaning Composition for Cleaning Semiconductor Substrates Containing Cobalt and / or Copper)

[0086] The semiconductor substrate cleaning composition according to a preferred embodiment of the present invention is preferably used for cleaning semiconductor substrates containing cobalt and / or copper. Furthermore, the semiconductor substrate cleaning composition according to a preferred embodiment of the present invention is more preferably used for cleaning semiconductor substrates containing both cobalt and copper. Even when used to clean semiconductor substrates containing both cobalt and copper, the semiconductor substrate cleaning composition according to a preferred embodiment of the present invention exhibits high stability with hydrogen peroxide. It should be noted that cobalt and copper are used as metal wiring, etc., on semiconductor substrates.

[0087] In the semiconductor substrate, cobalt and copper may be used as simple metals (pure metals) or as alloys.

[0088] (Semiconductor Substrate Cleaning Composition for Cleaning a Semiconductor Substrate Having a Hard Mask Containing Titanium or Titanium Nitride)

[0089] The semiconductor substrate cleaning composition of the present invention is preferably used for cleaning a semiconductor substrate having a hard mask comprising at least one member selected from the group consisting of titanium and titanium nitride, and more preferably for cleaning a semiconductor substrate having a hard mask comprising titanium nitride. Furthermore, the composition is preferably used for cleaning a semiconductor substrate having a hard mask comprising at least one member selected from the group consisting of titanium and titanium nitride, and more preferably for cleaning a semiconductor substrate having a hard mask comprising titanium nitride.

[0090] (Semiconductor Substrate Cleaning Composition for Cleaning a Semiconductor Substrate Having an Etching Stop Layer Containing Aluminum Nitride)

[0091] The semiconductor substrate cleaning composition of the present invention is preferably used for cleaning a semiconductor substrate having an etching stopper layer containing aluminum nitride.

[0092] [Cleaning method]

[0093] The cleaning method of the present invention is a method for removing the hard mask layer from a semiconductor substrate having an etch stop layer containing aluminum nitride and a hard mask layer on a metal wiring containing copper and / or cobalt using the semiconductor substrate cleaning composition.

[0094] In the present invention, the hard mask layer preferably comprises at least one member selected from the group consisting of titanium and titanium nitride, more preferably titanium nitride. Furthermore, in the present invention, the hard mask layer preferably comprises at least one member selected from the group consisting of titanium and titanium nitride, more preferably titanium nitride.

[0095] The cleaning method according to a preferred embodiment of the present invention can suppress damage to the etch stop layer even when applied to a semiconductor substrate having an etch stop layer containing aluminum nitride, and can efficiently remove dry etching residues and hard masks in the semiconductor substrate.

[0096] In the cleaning method of the present invention, the method for bringing the semiconductor substrate cleaning composition of the present invention into contact with the semiconductor substrate is not particularly limited. For example, a method in which the semiconductor substrate cleaning composition of the present invention is brought into contact with the semiconductor substrate by dropwise addition (single-wafer spinning process) or spraying (spraying process) or a method in which the semiconductor substrate is immersed in the semiconductor substrate cleaning composition of the present invention can be employed. In the present invention, any method can be employed.

[0097] The temperature during cleaning in the cleaning method of the present invention is not particularly limited, but is preferably 20 to 80° C., more preferably 25 to 70° C. Ultrasonic waves may also be used during cleaning.

[0098] The cleaning time in the cleaning method of the present invention is not particularly limited, but is preferably 0.3 to 20 minutes, more preferably 0.5 to 10 minutes.

[0099] The pH of the cleaning liquid in the cleaning method of the present invention is preferably 7-12, more preferably 7.5-11, further preferably 8-10, and particularly preferably 8-9.

[0100] In the cleaning method of the present invention, it is preferred to further rinse with a rinsing liquid containing water, alcohol, or the like after cleaning.

[0101] [Method for manufacturing semiconductor substrate]

[0102] The semiconductor substrate manufacturing method of the present invention includes the following steps: using the semiconductor substrate cleaning composition described above to remove the hard mask layer from a semiconductor substrate having an etch stop layer comprising aluminum nitride and a hard mask layer on a metal wiring comprising copper and / or cobalt. A specific semiconductor substrate manufacturing method is described below.

[0103] First, an etch stop layer, a barrier insulating film, a low-k interlayer insulating film, a hard mask layer, and a photoresist are stacked on a substrate such as silicon having a barrier metal, metal wiring, a low-k interlayer insulating film, and, if necessary, a metal-coated silicon substrate. The photoresist is then selectively exposed and developed to form a photoresist pattern. The photoresist pattern is then dry-etched and transferred to the hard mask layer. The photoresist pattern is then removed, and the low-k interlayer insulating film and the barrier insulating film are dry-etched using the hard mask layer as an etching mask. The aforementioned process, i.e., the process of removing the hard mask layer from the semiconductor substrate using the semiconductor substrate cleaning composition, is then performed to obtain a semiconductor substrate having the desired metal wiring pattern.

[0104] Here, as substrate materials, silicon, amorphous silicon, polysilicon, glass, etc. can be used. As barrier metals, tantalum, tantalum nitride, ruthenium, manganese, magnesium, cobalt, and their oxides can be used. As metal wiring, copper or copper alloys, copper or copper alloys with cobalt or cobalt alloys formed as cover metals, cobalt or cobalt alloys, etc. can be used. As low-k interlayer insulating films, polysiloxane-based OCD (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.), carbon-doped silicon oxide (SiOC)-based BlackDiamond (trade name, manufactured by Applied Materials Co., Ltd.), etc. can be used.

[0105] Aluminum nitride can be used as the etching stopper layer, silicon nitride, silicon carbide, silicon carbide nitride, or the like can be used as the barrier insulating film, and titanium, titanium nitride, or the like can be used as the hard mask layer.

[0106] According to the method for producing a semiconductor substrate of the present invention, since it includes the step of removing unnecessary components using the semiconductor substrate cleaning composition, it is possible to produce high-precision, high-quality semiconductor substrates with good yield.

[0107] Example

[0108] Next, the present invention will be described in more detail using Examples and Comparative Examples, but the present invention is not limited to these Examples.

[0109] <Analysis and Evaluation Methods>

[0110] pH

[0111] The pH of the semiconductor substrate cleaning composition was measured by a glass electrode method (F-55S benchtop pH meter manufactured by HORIBA, standard ToupH electrode 9165S-10D manufactured by HORIBA, temperature: 25°C).

[0112] Etching rate evaluation

[0113] [Titanium nitride]

[0114] A 2 cm square test piece was cut from a silicon wafer (manufactured by Advantech) on which a titanium nitride film with a thickness of 1000 angstroms was formed by PVD (physical vapor deposition). The film thickness was measured using a fluorescent X-ray analyzer (EA1400 manufactured by Hitachi). The piece was then immersed in a semiconductor substrate cleaning composition at 50°C for 2 minutes, then rinsed with ultrapure water at room temperature, and the film thickness was again measured using a fluorescent X-ray analyzer. The reduction in film thickness per unit time was thus determined.

[0115] [Aluminum Nitride]

[0116] A 1 cm square test piece was cut from a silicon wafer (manufactured by Philtech) on which a 250 angstrom thick aluminum nitride film was formed by ALD (atomic layer deposition) on a 1000 angstrom thick thermal oxide film. The film thickness was measured using a spectroscopic ellipsometer (UVISELPlus, manufactured by HORIBA), and then the piece was immersed in a semiconductor substrate cleaning composition at 50°C for 15 minutes. The piece was then rinsed with ultrapure water at room temperature and the film thickness was measured again using a spectroscopic ellipsometer to determine the reduction in film thickness per unit time.

[0117] [Copper and cobalt]

[0118] A 2 cm square test piece was cut from a silicon wafer (manufactured by Philtech) on which a 10,000 angstrom thick electrolytic copper plating was formed on a 1,000 angstrom thick PVD seed layer and annealed, or a silicon wafer (manufactured by Advantech) on which a 2,000 angstrom thick cobalt film was formed by PVD, and immersed in a semiconductor substrate cleaning composition at 50°C for 5 minutes. The semiconductor substrate cleaning composition after immersion was diluted 10 to 20 times with 1% by mass nitric acid, and the metal concentration was measured using an inductively coupled plasma emission spectrometer (SPECTROGREEN manufactured by Hitachi High-Technologies Corporation). The concentration of copper or cobalt before dilution (metal concentration) was calculated and substituted into the following formula to calculate the etching rate (ER) of copper or cobalt. It should be noted that the density of copper is set to 8.96 g / cm 3 The density of cobalt is set to 8.90 g / cm 3 Perform calculations.

[0119]

[0120] <Semiconductor substrate cleaning composition>

[0121] (Example 1)

[0122] A semiconductor substrate cleaning composition was obtained by blending hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP), phosphoric acid, boric acid, and water in the mass ratios shown in Table 1. The obtained compositions were used to perform the evaluations shown in Table 1.

[0123] (Examples 2-3)

[0124] A semiconductor substrate cleaning composition was obtained by blending hydrogen peroxide, potassium hydroxide or tetramethylammonium hydroxide (TMAH), ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP), phosphoric acid, boric acid, and water in the mass ratios shown in Table 1. The obtained compositions were used to perform the evaluations shown in Table 1.

[0125] (Examples 4-5)

[0126] A semiconductor substrate cleaning composition was obtained by blending hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), propylenediaminetetrakis(methylenephosphonic acid) (PDTMP), phosphoric acid, boric acid, and water in the mass ratios shown in Table 1. The obtained compositions were used to perform the evaluations shown in Table 1.

[0127] (Examples 6-7)

[0128] A semiconductor substrate cleaning composition was prepared by mixing hydrogen peroxide, potassium hydroxide (KOH), tetraethylammonium hydroxide (TEAH) or benzyltrimethylammonium hydroxide (BTMAH), ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP), phosphoric acid, boric acid, and water in the mass ratios shown in Table 1. The obtained compositions were used to perform the evaluations shown in Table 1.

[0129] (Comparative Example 1)

[0130] A semiconductor substrate cleaning composition was prepared by mixing hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP), and water in the mass ratios shown in Table 1. The evaluations shown in Table 1 were performed using the resulting composition. The results showed that the etching rate for aluminum nitride was higher than that of the compositions containing phosphoric acid and boric acid (Examples 1 to 7).

[0131] (Comparative Example 2)

[0132] A semiconductor substrate cleaning composition was prepared by mixing hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP), phosphoric acid, and water in the mass ratios shown in Table 1. The evaluations shown in Table 1 were performed using the resulting compositions. The results showed that the etching rates for cobalt were higher than those for compositions containing phosphoric acid and boric acid (Examples 1 to 7) and compositions not containing phosphoric acid (Comparative Examples 1 and 3).

[0133] (Comparative Example 3)

[0134] A semiconductor substrate cleaning composition was prepared by mixing hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP), boric acid, and water in the mass ratios shown in Table 1. The evaluations shown in Table 1 were performed using the resulting compositions. The etching rates for aluminum nitride were higher than those for the compositions containing phosphoric acid and boric acid (Examples 1 to 7).

[0135] [Table 1]

[0136]

[0137] TMAH: Tetramethylammonium hydroxide

[0138] TEAH: Tetraethylammonium hydroxide

[0139] BTMAH: benzyltrimethylammonium hydroxide

[0140] EDTMP: Ethylenediaminetetrakis(methylenephosphonic acid)

[0141] PDTMP: propylene diamine tetrakis(methylene phosphonic acid)

[0142] (Examples 8 to 12)

[0143] A semiconductor substrate cleaning composition was prepared by mixing hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), phosphoric acid, boric acid, diethylenetriaminepentaacetic acid (DTPA), and water in the mass ratios shown in Table 2. The obtained compositions were used to perform the evaluations shown in Table 2.

[0144] (Example 13)

[0145] Hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), propylenediaminetetrakis(methylenephosphonic acid) (PDTMP), phosphoric acid, boric acid, trans-1,2-cyclohexanediaminetetraacetic acid monohydrate (CyDTA), and water were blended in the mass ratios shown in Table 2 to obtain a semiconductor substrate cleaning composition. The resulting composition was used to perform the evaluations shown in Table 2.

[0146] (Examples 14 to 17)

[0147] Semiconductor substrate cleaning compositions were obtained by replacing trans-1,2-cyclohexanediaminetetraacetic acid monohydrate (CyDTA) in Example 13 with triethylenetetraaminehexaacetic acid (TTHA), hydroxyethyliminodiacetic acid (HIDA), hydroxyethylethylenediaminetriacetic acid (HEDTA), or oxalic acid, and blending the components at the mass ratios shown in Table 2. The resulting compositions were used to perform the evaluations shown in Table 2.

[0148] (Comparative Example 4)

[0149] A semiconductor substrate cleaning composition was obtained by mixing hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), diethylenetriaminepentaacetic acid (DTPA), and water in the mass ratios shown in Table 2. The evaluations shown in Table 2 were performed using the obtained compositions. The etching rates for aluminum nitride were higher than those for the compositions containing phosphoric acid and boric acid (Examples 8 to 12).

[0150] (Comparative Example 5)

[0151] A semiconductor substrate cleaning composition was prepared by blending hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), phosphoric acid, diethylenetriaminepentaacetic acid (DTPA), and water in the mass ratios shown in Table 2. The evaluations shown in Table 2 were conducted using the resulting compositions. The results showed that the etching rates for cobalt were higher than those for compositions containing phosphoric acid and boric acid (Examples 8 to 12) and compositions not containing phosphoric acid (Comparative Examples 4 and 6).

[0152] (Comparative Example 6)

[0153] A semiconductor substrate cleaning composition was prepared by mixing hydrogen peroxide, potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), boric acid, diethylenetriaminepentaacetic acid (DTPA), and water in the mass ratios shown in Table 2. The evaluations shown in Table 2 were performed using the resulting compositions. The etching rates for aluminum nitride were higher than those for the compositions containing phosphoric acid and boric acid (Examples 8 to 12).

[0154] [Table 2]

[0155]

[0156] TMAH: Tetramethylammonium hydroxide

[0157] DTPMP: diethylenetriamine penta(methylenephosphonic acid)

[0158] PDTMP: propylene diamine tetrakis(methylene phosphonic acid)

[0159] DTPA: Diethylenetriaminepentaacetic acid

[0160] CyDTA: trans-1,2-cyclohexanediaminetetraacetic acid monohydrate

[0161] TTHA: triethylenetetraaminehexaacetic acid

[0162] HIDA: Hydroxyethyliminodiacetic acid

[0163] HEDTA: Hydroxyethylethylenediaminetriacetic acid

[0164] Description of Reference Numerals

[0165] 1: Hard mask layer

[0166] 2: Etch stop layer

[0167] 3: Metal wiring

Claims

1. A semiconductor substrate cleaning composition comprising hydrogen peroxide, an alkaline compound, phosphoric acid and / or its salt, boric acid and / or its salt, aminopolymethylenephosphonic acid, and water, wherein the alkaline compound comprises at least one member selected from the group consisting of quaternary ammonium hydroxide and potassium hydroxide.

2. The semiconductor substrate cleaning composition according to claim 1, wherein The salt of phosphoric acid is at least one selected from the group consisting of quaternary ammonium phosphate and potassium phosphate, and the salt of boric acid is at least one selected from the group consisting of quaternary ammonium borate and potassium borate.

3. The semiconductor substrate cleaning composition according to claim 1 or 2, wherein The content of the phosphoric acid and / or its salt in the semiconductor substrate cleaning composition is 0.05 to 2% by mass as calculated as phosphoric acid, and the content of the boric acid and / or its salt in the semiconductor substrate cleaning composition is 0.1 to 4% by mass as calculated as boric acid.

4. The semiconductor substrate cleaning composition according to any one of claims 1 to 3, wherein The content of the hydrogen peroxide in the semiconductor substrate cleaning composition is 10 to 30% by mass.

5. The semiconductor substrate cleaning composition according to any one of claims 1 to 4, wherein The content of the aminopolymethylenephosphonic acid in the semiconductor substrate cleaning composition is 0.00005 to 0.01 mass %.

6. The semiconductor substrate cleaning composition according to any one of claims 1 to 5, wherein The content of the quaternary ammonium hydroxide in the semiconductor substrate cleaning composition is 0.005 to 10% by mass.

7. The semiconductor substrate cleaning composition according to any one of claims 1 to 6, wherein The content of the potassium hydroxide in the semiconductor substrate cleaning composition is 0.005 to 5% by mass.

8. The semiconductor substrate cleaning composition according to any one of claims 1 to 7, wherein The pH of the semiconductor substrate cleaning composition is 7-12.

9. The semiconductor substrate cleaning composition according to any one of claims 1 to 8, wherein The quaternary ammonium hydroxide is at least one selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and benzyltrimethylammonium hydroxide.

10. The semiconductor substrate cleaning composition according to any one of claims 1 to 9, wherein The aminopolymethylenephosphonic acid is at least one selected from the group consisting of aminotri(methylenephosphonic acid), ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid) and 1,2-propylenediaminetetra(methylenephosphonic acid).

11. The semiconductor substrate cleaning composition according to any one of claims 1 to 10, further comprising at least one hydrogen peroxide stabilizer selected from the group consisting of oxalic acid, diethylenetriaminepentaacetic acid, hydroxyethyliminodiacetic acid, 5-phenyl-1H-tetrazole, triethylenetetraaminehexaacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, 8-hydroxyquinoline, L(+)-isoleucine, DL-valine, L(-)-proline, hydroxyethylethylenediaminetriacetic acid, N,N-bis(2-hydroxyethyl)glycine, glycine, L-tryptophan, 2,6-pyridinedicarboxylic acid, benzothiazole, and DL-alanine.

12. The semiconductor substrate cleaning composition according to claim 11, wherein The content of the hydrogen peroxide stabilizer in the semiconductor substrate cleaning composition is 0.0001 to 5% by mass.

13. The semiconductor substrate cleaning composition according to any one of claims 1 to 12, which substantially does not contain ammonia and ammonium ions NH4 + .

14. A method for cleaning a semiconductor substrate, wherein: A semiconductor substrate having an etch stop layer containing aluminum nitride and a hard mask layer on a metal wiring containing copper and / or cobalt, wherein the hard mask layer is removed using the semiconductor substrate cleaning composition according to any one of claims 1 to 13.

15. The method for cleaning a semiconductor substrate according to claim 14, wherein: The hard mask layer includes at least one selected from the group consisting of titanium and titanium nitride.

16. A method for manufacturing a semiconductor substrate, comprising the step of removing an etching stop layer comprising aluminum nitride and a hard mask layer on a metal wiring comprising copper and / or cobalt using the semiconductor substrate cleaning composition according to any one of claims 1 to 13.

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