Photoresist developing solution

Abstract

Provided is a photoresist developing solution comprising (A), (B), (C), and (D). (A) is a quaternary ammonium ion represented by formula (1), (B) is a halide ion, (C) is a hydroxide ion, and (D) is water. (In the formula, R1, R}2, R3, and R4 are each independently a C1-16 alkyl group; at least one of R1, R2, R3, and R4 is a C2-16 alkyl group; and not all of R1, R2, R3, and R4 are the same alkyl group.)

Description

Photoresist developer

[0001] The present invention relates to a photoresist developer.

[0002] Quaternary ammonium compounds are used as phase transfer catalysts, surfactants, disinfectants, etc. Among quaternary ammonium compounds, tetramethylammonium hydroxide, in particular, is a type of organic alkali that exhibits strong basicity and is used in alkaline aqueous solutions for semiconductors, which are used for cleaning, etching, developing solutions, etc. during semiconductor manufacturing.

[0003] For example, Patent Document 1 discloses an aqueous solution of 2.35 wt % tetramethylammonium hydroxide, which contains metal ions and halogen ions at predetermined values.

[0004] Japanese Patent Application Publication No. 4-226466

[0005] However, the present inventors have found that when an aqueous solution of tetramethylammonium hydroxide (hereinafter also referred to as TMAH) is used as a photoresist developer, the photoresist developer may have insufficient ability to develop the photoresist layer. If the ability to develop the photoresist layer is insufficient, residues of the photoresist layer may remain on the substrate during development, resulting in a defective pattern shape.

[0006] Therefore, an object of the present invention is to provide a photoresist developer that has a high ability to develop a photoresist layer and produces a good pattern shape. Another object of the present invention is to provide a photoresist development method that produces a good pattern shape. Another object of the present invention is to provide a method for manufacturing a semiconductor device that produces a good pattern shape.

[0007] The present inventors have conducted extensive research to obtain a photoresist developer that produces a good pattern shape, and as a result have found that a photoresist developer containing a specific quaternary ammonium ion, a halide ion, a hydroxide ion, and water can produce a good pattern shape, thereby completing the present invention.

[0008] That is, the present invention is configured as follows: Item 1: A photoresist developer comprising the following (A), (B), (C), and (D): (A) a quaternary ammonium ion represented by the following formula (1), (B) a halide ion, (C) a hydroxide ion, and (D) water. (In the formula, R １ , R ２ , R ３ , and R ４ are each independently an alkyl group having 1 to 16 carbon atoms, provided that R １ , R ２ , R ３ , and R ４ Among these, one or more alkyl groups have 2 to 16 carbon atoms, and R １ , R ２ , R ３ , and R ４ Item 2. The photoresist developer according to Item 1, wherein the surface tension of the photoresist developer is 73.0 mN / m or less at 25° C. Item 3. The photoresist developer according to Item 1, wherein the R １ , R ２ , and R ３ is a methyl group, and R ４is an alkyl group having 2 to 16 carbon atoms. Item 4. The photoresist developer according to any one of Items 1 to 3, wherein the (B) halide ion is a chloride ion or a bromide ion. Item 5. The photoresist developer according to any one of Items 1 to 4, wherein the parts by weight of the halide ion is 0.0000001 to 0.01 parts by weight, based on 1 part by weight of the hydroxide ion in the photoresist developer. Item 6. The photoresist developer according to any one of Items 1 to 5, further comprising one or more compounds selected from the group consisting of alcohols and amines. Item 7. The photoresist developer according to any one of Items 1 to 6, which is a photoresist developer for developing an exposed photoresist layer, comprising a photosensitive resin. Item 8. The photoresist developer according to any one of Items 1 to 7, which contains one or more metal ions selected from the group consisting of calcium ions, sodium ions, potassium ions, chromium ions, nickel ions, iron ions, lead ions, and aluminum ions, and the content of each metal ion in the photoresist developer is independently 1 ppb or less. Item 9. The photoresist developer according to any one of Items 1 to 8, which is a photoresist developer for developing a photoresist layer exposed with one or more excimer lasers selected from the group consisting of KrF excimer lasers and ArF excimer lasers. Item 10. The photoresist developer according to any one of Items 1 to 9, wherein, in a dissolution rate evaluation test at 23°C for a photoresist layer containing a polyhydroxystyrene resin, the ratio of hydroxyl groups to tert-butoxycarbonyl groups in the polyhydroxystyrene resin is 70:30 on a mass basis, the photoresist layer has a thickness of 200 nm, and the dissolution rate of the photoresist layer when using the photoresist developer is 110% or more of the dissolution rate of the photoresist layer when using a photoresist developer containing tetramethylammonium hydroxide. Item 11. The photoresist developer according to any one of Items 1 to 10, further comprising a surfactant, the concentration of the surfactant in the photoresist developer being less than 100 ppm by mass.Item 12. The photoresist developer according to any one of Items 1 to 11, further comprising tetramethylammonium ions. Item 13. A photoresist development method, comprising a developing step of developing an exposed photoresist layer using the photoresist developer according to any one of Items 1 to 12. Item 14. A method for manufacturing a semiconductor device, comprising: an exposure step of irradiating a photoresist layer on a substrate with light through a photomask having a predetermined pattern; and a developing step of developing the photoresist layer exposed in the exposure step to form a resist pattern corresponding to the pattern of the photomask, wherein in the developing step, the exposed photoresist layer is developed using the photoresist developer according to any one of Items 1 to 12.

[0009] According to the present invention, a photoresist developer that produces a good pattern shape is provided, a photoresist developing method that produces a good pattern shape is provided, and a semiconductor device manufacturing method that produces a good pattern shape is also provided.

[0010] FIG. 2 is an explanatory diagram showing an electrolytic cell.

[0011] Although the present invention will be described in detail below with reference to the preferred embodiments, the present invention is not limited to these embodiments as long as they do not depart from the spirit of the present invention. Furthermore, the present invention can be implemented by modifying it as desired within the scope of the present invention.

[0012] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less. Furthermore, when a numerical range is written in stages, the upper and lower limits of each numerical range can be combined arbitrarily. Furthermore, in this specification, the term "(meth)acrylic resin" refers to a methacrylic resin and / or an acrylic resin. Furthermore, a "monomer unit" refers to the reacted form of a monomer substance in a polymer.

[0013] The photoresist developer of the present invention contains the following components (A), (B), (C), and (D): (A) a quaternary ammonium ion represented by the following formula (1), (B) a halide ion, (C) a hydroxide ion, and (D) water. (In the formula, R １ , R ２ , R ３ , and R ４ are each independently an alkyl group having 1 to 16 carbon atoms (preferably 1 to 8, more preferably 1 to 4), provided that R １ , R ２ , R ３ , and R ４ wherein one or more alkyl groups have 2 to 16 carbon atoms (preferably 2 to 8, more preferably 2 to 4), and R １ , R ２ , R ３ , and R ４ are not all the same alkyl group.)

[0014] When the photoresist developer contains the quaternary ammonium ion represented by the above formula (1), the pattern shape is more likely to be improved than when an aqueous solution of tetramethylammonium hydroxide is used as the photoresist developer. Although the reason for this improvement in the pattern shape is not clear, the inventors hypothesize it as follows.

[0015] In photolithography using a photoresist developer, a photoresist layer provided on a substrate is exposed to light through a photomask having a predetermined pattern. During this process, the photoresist in the exposed regions of the exposed photoresist layer undergoes a chemical reaction due to the light. Meanwhile, the photoresist in the unexposed regions of the photoresist layer does not undergo a chemical reaction. The photoresist that has undergone a chemical reaction and the photoresist that has not undergone a chemical reaction differ in reactivity, solubility in solvents, and other properties, resulting in changes in developability. The exposed photoresist layer is then developed using a photoresist developer to form a resist pattern corresponding to the photomask. In this way, the photoresist in the exposed regions undergoes a chemical reaction due to the light. However, this chemical reaction is less likely to proceed near the borders of the photomask than near the center of the photomask. Therefore, for example, if the photoresist is a positive photoresist, the photoresist near the borders of the photomask does not have sufficient solubility in the developer, resulting in residue remaining on the substrate and resulting in a defective pattern shape.

[0016] On the other hand, the quaternary ammonium ion represented by the above formula (1) is R １ , R ２ , R ３ , and R ４ are each independently an alkyl group having 1 to 16 carbon atoms, and R １ , R ２ , R ３ , and R ４ are not all the same alkyl group, and R １ , R ２ , R ３ , and R ４Since at least one of the alkyl groups has 2 to 16 carbon atoms, the quaternary ammonium ion has an asymmetric shape centered on the nitrogen atom, and at least one alkyl group has 2 to 16 carbon atoms. Therefore, the quaternary ammonium ion represented by formula (1) has lipophilic properties due to the long carbon atoms in the alkyl group. As a result, for example, in the case of a positive photoresist, the affinity for areas where chemical reaction upon exposure is difficult to proceed is enhanced. This improves the contact between the developer and the photoresist, and even photoresist near the border of the photomask where chemical reaction has not progressed sufficiently can be sufficiently dissolved, taking into account the influence of the affinity of the polar surface to the developer. As a result, residues are less likely to remain during development, making it possible to obtain a good pattern shape.

[0017] R １ ~R ４ If the number of carbon atoms in R exceeds the above range, the lipophilicity becomes too high, and the development speed may decrease. １ , R ２ , R ３ , and R ４ Among these, it is also preferable that the one or more alkyl groups have 2 to 16 carbon atoms, more preferably 3 to 16 carbon atoms, even more preferably 3 to 8 carbon atoms, and most preferably 3 or 4 carbon atoms.

[0018] In the above formula (1), R １ , R ２ , R ３ , and R ４ In other words, the compounds shown in (1) to (3) below are preferred. (1) R １ , R ２ , R ３ , and R ４ (2) A compound in which any three of R are the same alkyl group and the remaining one is a different alkyl group from the above. １ , R ２ , R ３ , and R ４ (3) A compound in which any two of R are the same alkyl group and the remaining two are different alkyl groups (the remaining two may be the same or different).１ , R ２ , R ３ , and R ４ are all different alkyl groups

[0019] In the case of (1) above, R １ , R ２ , R ３ , and R ４ and the remaining one is an alkyl group having 1 to 16 carbon atoms, and the first three and the remaining one are different alkyl groups, and either the first three or the remaining one has 2 to 16 carbon atoms. １ , R ２ , R ３ , and R ４ Preferably, three of the groups R are the same, and the remaining one is an alkyl group having 2 to 16 carbon atoms different from the groups R. In this case, the compound represented by formula (1) has two types of alkyl groups. １ , R ２ , R ３ , and R ４ A compound in which any three of R are methyl groups and the remaining alkyl group has 2 to 16 carbon atoms is preferred. １ , R ２ , R ３ , and R ４ When any three of the groups are methyl groups and the remaining one has 2 to 16 carbon atoms, the compound is more likely to function as a surfactant, as described below. Among these, compounds in which the remaining alkyl group has 2 to 8 carbon atoms are more preferred, and compounds in which the remaining alkyl group has 2 to 4 carbon atoms are even more preferred. Furthermore, compounds in which the remaining alkyl group has 3 to 16 carbon atoms are also preferred, and compounds in which the remaining alkyl group has 3 to 8 carbon atoms are even more preferred, and compounds in which the remaining alkyl group has 3 to 4 carbon atoms are even more preferred. Within the above ranges, the pattern shape is more likely to be better.

[0020] In the case of (2) above, R １ , R ２ , R ３ , and R ４and R are the same alkyl groups having 1 to 16 carbon atoms, the remaining two are alkyl groups having 1 to 16 carbon atoms different from the first two, and the remaining two are the same or different alkyl groups, and either the first two or the remaining two are alkyl groups having 2 to 16 carbon atoms. In this case, the compound represented by formula (1) has two or three types of alkyl groups. In this embodiment, R １ , R ２ , R ３ , and R ４ A compound in which any two of R are methyl groups and the remaining two alkyl groups have 2 to 16 carbon atoms is preferred. １ , R ２ , R ３ , and R ４ Among these, compounds in which the remaining two alkyl groups have 2 to 8 carbon atoms are more preferred, and compounds in which the remaining two alkyl groups have 2 to 4 carbon atoms are even more preferred.

[0021] In the case of (3) above, R １ , R ２ , R ３ , and R ４ are all different alkyl groups, at least one of which has 2 to 16 carbon atoms. In this case, the compound represented by formula (1) has four types of alkyl groups. In this embodiment, R １ , R ２ , R ３ , and R ４ A compound in which any one of R is a methyl group and the remaining three alkyl groups have 2 to 16 carbon atoms is preferred. １ , R ２ , R ３ , and R ４ Among these, compounds in which the remaining three alkyl groups have 2 to 8 carbon atoms are more preferred, and compounds in which the remaining three alkyl groups have 2 to 4 carbon atoms are even more preferred.

[0022] Specific examples of the quaternary ammonium ion represented by the above formula (1) include an ethyltrimethylammonium ion, a diethyldimethylammonium ion, a triethylmethylammonium ion, a propyltrimethylammonium ion, a butyltrimethylammonium ion, etc. These quaternary ammonium ions may be used alone or in combination.

[0023] The halide ion is not particularly limited, but specific examples include one or more selected from the group consisting of chloride ion, bromide ion, and iodide ion, and chloride ion or bromide ion is preferred.

[0024] The weight parts of halide ions in a photoresist developer, where the weight of hydroxide ions is taken as 1 part by weight, is not particularly limited, but is preferably 0.0000001 to 0.01 parts by weight, more preferably 0.0000001 to 0.001 parts by weight, and even more preferably 0.0000001 to 0.0005 parts by weight. The weight parts of halide ions vary greatly depending on the method for producing a photoresist developer, and a solution with reduced halide ions can be prepared, particularly by using a production method that involves electrolysis. The weight parts of halide ions can also be adjusted by changing conditions such as the structure of the electrolytic vessel used for electrolysis, the selection of a cation exchange membrane, and the current density.

[0025] If the photoresist developer contains a large amount of halide ions, the halide ions may remain on the surface of the semiconductor when the photoresist layer is developed. In such cases, scum may be generated during development, and the physical properties of the semiconductor may be deteriorated. When the photoresist developer is used, the pattern shape during development is likely to be improved by using the photoresist developer with a halide ion content within the above range.

[0026] The weight parts of halide ions in a photoresist developer can be analyzed by ion chromatography. When the photoresist developer is highly concentrated, neutralization analysis is particularly effective. Specifically, before introducing the photoresist developer into anion ion chromatography, the cations in the photoresist developer are exchanged for hydrogen ions, and the hydroxide ions are converted to water. This removes the hydroxide ions. Furthermore, concentration enhances sensitivity. This method allows for the measurement of low halide ion concentrations.

[0027] The photoresist developer contains hydroxide ions. The fact that the photoresist developer contains the quaternary ammonium ion represented by formula (1) above and hydroxide ions can also be said to indicate that the photoresist developer contains a quaternary ammonium hydroxide (hydroxide of the quaternary ammonium ion represented by formula (1)) containing the quaternary ammonium ion represented by formula (1) above and hydroxide ions. The inclusion of the quaternary ammonium ion represented by formula (1) allows the photoresist developer to be used as a photoresist developer.

[0028] The concentrations of the quaternary ammonium ions represented by formula (1) and hydroxide ions in the photoresist developer are not particularly limited, but are preferably prepared at 1.0 to 65.0 mass% as quaternary ammonium hydroxide. For example, the quaternary ammonium hydroxide is more preferably used at 1.0 to 10.0 mass%, and even more preferably at 1.0 to 7.0 mass%. It is also more preferably 1.0 to 4.5 mass%. Furthermore, the molar concentration of the quaternary ammonium hydroxide is preferably 0.10 to 1.0 mol / L, more preferably 0.10 to 0.50 mol / L, and even more preferably 0.10 to 0.33 mol / L.

[0029] Furthermore, a high-concentration photoresist developer containing a high-concentration hydroxide of the quaternary ammonium ion represented by formula (1) can be diluted and used. By increasing the concentration, the volume required for transportation can be reduced, thereby reducing transportation costs. Furthermore, even if contamination occurs in the photoresist developer during filling into a container or transportation, the effect of contamination can be reduced by the amount of dilution compared to when the photoresist developer is not diluted. The concentration of the hydroxide of the quaternary ammonium ion represented by formula (1) in the high-concentration photoresist developer before dilution is preferably 10.0 to 50.0 mass%, more preferably 20.0 to 40.0 mass%. The concentration of the quaternary ammonium hydroxide can be confirmed by neutralization titration with an acid, or the like.

[0030] Furthermore, the concentration of the quaternary ammonium ion represented by the above formula (1) in the photoresist developer is preferably 0.8 to 52.9 mass%. It is more preferably 0.8 to 8.2 mass%, and even more preferably 0.8 to 5.7 mass%. The concentration of the quaternary ammonium hydroxide represented by formula (1) in the high-concentration photoresist developer is preferably 8.0 to 40.7 mass%, and even more preferably 16.2 to 32.5 mass%. The concentration of hydroxide ions in the photoresist developer is preferably 0.15 to 12.2 mass%. It is more preferably 0.15 to 1.9 mass%, and even more preferably 0.15 to 1.3 mass%. The concentration of hydroxide ions in the high-concentration photoresist developer is preferably 1.9 to 9.4 mass%, and even more preferably 3.7 to 7.5 mass%.

[0031] The photoresist developer contains water. The type of water is not particularly limited, and any known water can be used, with ultrapure water having reduced metal impurities being particularly preferred. The water content in the photoresist developer is not particularly limited, but is preferably 90.0 to 99.0 mass %, more preferably 93.0 to 99.0 mass %, and even more preferably 95.5 to 99.0 mass %.

[0032] The photoresist developer may also contain one or more compounds selected from the group consisting of alcohols and amines. The concentration of the one or more compounds selected from the group consisting of alcohols and amines in the photoresist developer is not particularly limited, but is preferably 0.1 to 10,000 ppm by mass, and more preferably 0.1 to 100 ppm by mass. The alcohol is not particularly limited, and known alcohols can be used. Examples include primary alcohols such as methanol, ethanol, and 1-propanol, secondary alcohols such as 2-propanol and 2-butanol, and tertiary alcohols such as 2-methyl-2-propanol. The valence of the alcohol is not particularly limited, and either monohydric alcohols or dihydric or higher alcohols may be used. Among these, alcohols having 16 or fewer carbon atoms (more preferably 2 to 8, even more preferably 2 to 4) are preferred, as longer chains increase the likelihood of adsorption inhibition during development.

[0033] The amine is not particularly limited, and known amines can be used. Examples include primary amines such as methylamine, secondary amines such as dimethylamine, and tertiary amines such as trimethylamine. The amine has no particular limit on its valence, and either monovalent amines or divalent or higher amines can be used. Among these, amines having 16 or fewer carbon atoms (more preferably 2 to 8, and even more preferably 2 to 4) are preferred, as longer chains are more likely to cause adsorption inhibition during development.

[0034] It is desirable that the photoresist developer contains one or more metal ions selected from the group consisting of calcium ions, sodium ions, potassium ions, chromium ions, nickel ions, iron ions, lead ions, and aluminum ions, and that the content of each metal ion in the photoresist developer is each independently equal to or less than a specific concentration. It is particularly desirable that the concentrations of chromium ions, nickel ions, iron ions, and aluminum ions are each equal to or less than a specific concentration. Reducing the metal ions reduces metal contamination on the surface of the substrate after development, which facilitates a reduction in the rate of semiconductor malfunction.

[0035] Furthermore, the content of each metal ion in the photoresist developer is preferably independently 1 ppb or less, more preferably 0.5 ppb or less, and even more preferably 0.2 ppb or less. The lower limit is not particularly limited, but may be 0.1 ppt or more and 1 ppb or less, 0.1 ppt or more and 0.5 ppb or less, or 0.1 ppt or more and 0.2 ppb or less. The metal ion concentration can be measured by ICP-MS (inductively coupled plasma mass spectrometry). Metal ions may be mixed in due to contamination from manufacturing raw materials or liquid-contacting parts, etc. Therefore, if the content of each metal ion is high, it can be reduced by purification using ion exchange resins, etc.

[0036] It is also preferable that the photoresist developer be low in toxicity. For example, when the photoresist developer contains a quaternary ammonium ion represented by the above formula (1), it is less toxic than when a tetramethylammonium hydroxide aqueous solution is used as the photoresist developer. To evaluate the toxicity of the photoresist developer, it is preferable that the median lethal dose (LD50) value, calculated based on 100% by mass of the hydroxide of the quaternary ammonium ion, exceeds 50 mg / kg in a toxicity test using rats based on the OECD TG420 acute oral toxicity. This leads to higher safety during use and a lower environmental impact. Furthermore, in the GHS classification, an LD50 value of 50 mg / kg or less corresponds to Category 2, which requires stricter regulations for storage, transportation, etc., and a value of 5 mg / kg or less corresponds to Category 1, which is even stricter. Therefore, it is preferable that the LD50 value exceed 50 mg / kg. The LD50 value is more preferably more than 50 mg / kg and not more than 10,000 mg / kg, even more preferably more than 300 mg / kg and not more than 10,000 mg / kg, and particularly preferably more than 2,000 mg / kg and not more than 10,000 mg / kg.

[0037] The LD50 value can be adjusted by changing the type of quaternary ammonium ion represented by the above formula (1). １ , R ２ , and R ３ is an alkyl group having one carbon atom, and R４ is preferably an alkyl group having 2 to 4 carbon atoms (more preferably 3 to 4). More specifically, ethyltrimethylammonium ion, propyltrimethylammonium ion, and butyltrimethylammonium ion are preferred, and propyltrimethylammonium ion and butyltrimethylammonium ion are more preferred.

[0038] The photoresist developer may also contain a surfactant. The concentration of the surfactant in the photoresist developer is preferably less than 100 ppm by mass. The photoresist developer may not contain a surfactant. The quaternary ammonium ion represented by formula (1) contained in the photoresist developer has an asymmetric shape with respect to the nitrogen atom and has a structure represented by formula (1) of R １ , R ２ , R ３ , and R ４Among these, it is believed that when one or more alkyl groups have 2 to 16 carbon atoms, they themselves also function as surfactants. Specifically, the longer carbon atoms in the alkyl group are lipophilic, while the shorter carbon atoms are hydrophilic. Therefore, the quaternary ammonium ion represented by the above formula (1) has both a lipophilic and a hydrophilic portion in its ionic structure, and functions as a surfactant. Therefore, the photoresist developer may be completely free of surfactants, or, if it contains surfactants, its concentration may be as low as less than 100 ppm by mass. The surfactant concentration is more preferably less than 50 ppm by mass, even more preferably less than 30 ppm by mass, and particularly preferably less than 10 ppm by mass. By not including surfactants in the photoresist developer, or by including surfactants at a concentration of less than 100 ppm by mass, for example, foaming of the photoresist developer can be suppressed, and surfactant-derived impurities can be suppressed. Furthermore, when the quaternary ammonium hydroxide is recovered from the used developer by separation, purification, or the like, and then reused, it is necessary to add the surfactant again if it is needed in the developer. In this case, too, a low surfactant concentration can reduce the amount of surfactant to be added again. Furthermore, if the photoresist developer does not contain a surfactant, the recovered solution can be used as a developer as is. While the lower limit of the surfactant is not particularly specified, from the viewpoint of achieving the above-mentioned effect, it is preferable that the surfactant be contained in an amount of 0.01 mass ppm or more and 0.1 mass ppm or more. That is, the surfactant concentration may be, for example, 0.01 mass ppm or more and less than 100 mass ppm, 0.01 mass ppm or more and less than 50 mass ppm, 0.01 mass ppm or more and less than 30 mass ppm, 0.01 mass ppm or more and less than 10 mass ppm, or 0.1 mass ppm or more and less than 10 mass ppm. The surfactant is a compound having a hydrophilic group and a hydrophobic group (lipophilic group) in one molecule, such as a nonionic surfactant, anionic surfactant, cationic surfactant, or amphoteric surfactant. The surfactant is a compound different from the above-mentioned compounds that can be contained in the photoresist developer.

[0039] The photoresist developer may contain tetramethylammonium ions. The present inventors have found that when a photoresist developer contains only tetramethylammonium ions as quaternary ammonium ions, a large amount of surfactant may be required. The reason for this is presumed to be as follows. For example, when a photoresist developer contains quaternary ammonium ions, and the quaternary ammonium ions are tetramethylammonium ions, the quaternary ammonium ions have only methyl groups with a small number of carbon atoms. As a result, the tetramethylammonium ions are hydrophilic as a whole. That is, tetramethylammonium does not exhibit the surfactant effect. However, as described above, the quaternary ammonium ions represented by formula (1) contained in the photoresist developer of the present invention are believed to themselves function as surfactants. Therefore, even when tetramethylammonium, which does not exhibit the surfactant effect, is contained, the amount of surfactant can be reduced. Furthermore, when a photoresist developer contains both the quaternary ammonium ions represented by formula (1) and tetramethylammonium ions, the development performance of the photoresist developer is likely to be excellent. As described above, the quaternary ammonium ions represented by formula (1) are believed to also function as surfactants. Therefore, even when tetramethylammonium is contained, the developing performance is likely to be improved. In this case, as described above, the photoresist developer does not need to contain a surfactant.

[0040] When the photoresist developer contains tetramethylammonium ions, the photoresist developer contains tetramethylammonium ions and hydroxide ions. The fact that the photoresist developer contains tetramethylammonium ions and hydroxide ions can also be said to indicate that the photoresist developer contains tetramethylammonium hydroxide, which contains tetramethylammonium ions and hydroxide ions.

[0041] The concentration of tetramethylammonium ions in the photoresist developer is not particularly limited, and is preferably 1.0 to 30.0 mass% in terms of tetramethylammonium hydroxide. For example, tetramethylammonium hydroxide is more preferably 0.1 to 5.0 mass%, and even more preferably 0.5 to 3.0 mass%. Furthermore, the molar concentration of tetramethylammonium hydroxide is preferably 0.01 to 0.55 mol / L, more preferably 0.05 to 0.33 mol / L, and even more preferably 0.1 to 0.27 mol / L.

[0042] The concentration of tetramethylammonium ions in the photoresist developer is preferably 0.08 to 4.0% by mass, more preferably 0.4 to 2.4% by mass, and even more preferably 0.8 to 2.0% by mass.

[0043] The total concentration of tetramethylammonium ions and quaternary ammonium ions represented by formula (1) in the photoresist developer is preferably 0.5 to 6.0% by mass. It is more preferably 1.0 to 5.0% by mass, and even more preferably 1.2 to 4.0% by mass. The total concentration of tetramethylammonium hydroxide and the hydroxide of the quaternary ammonium ions represented by formula (1) in the photoresist developer is preferably 0.4 to 5.0% by mass. It is more preferably 0.8 to 4.0% by mass, and even more preferably 1.0 to 3.2% by mass. The total concentration of tetramethylammonium ions and quaternary ammonium ions represented by formula (1) in the high-concentration photoresist developer is preferably 10.0 to 50.0% by mass. It is more preferably 15.0 to 40.0% by mass, and even more preferably 20.0 to 30.0% by mass.

[0044] As described above, the quaternary ammonium ion represented by formula (1) is believed to also function as a surfactant. As a result, the surface tension of the photoresist developer is lower than that of an aqueous tetramethylammonium hydroxide solution. As a result, wettability of the photoresist during development is likely to be improved. Even when the photoresist developer contains tetramethylammonium ions, the surface tension is lower than that of an aqueous tetramethylammonium hydroxide solution, thereby improving development characteristics. The surface tension is measured using a surface tensiometer DY-300 (manufactured by Kyowa Interface Science Co., Ltd.). The surface tension of the photoresist developer at 25°C is preferably 73.0 mN / m or less, more preferably 72.0 mN / m or less, and even more preferably 71.0 mN / m or less. The measurement is performed in accordance with JIS 2241, "Test Method Using a Wilhelmy Surface Tensiometer."

[0045] The photoresist developer of the present invention has a high ability to develop a photoresist layer and produces a good pattern shape. The photoresist developer of the present invention can contain known additives used in conventional developers as appropriate, provided that the effects of the present invention are not impaired. Examples of such additives include wetting agents, stabilizers, and dissolution aids. These additives may be added alone or in combination of two or more.

[0046] Although the method for producing the photoresist developer is not particularly limited, it is preferably obtained by electrolyzing an aqueous quaternary ammonium halide solution from the viewpoint of suppressing the halide ion concentration. That is, it is preferable to include an electrolysis step of electrolyzing an aqueous quaternary ammonium halide solution. Specifically, it is preferable to include an electrolysis step of electrolyzing an aqueous quaternary ammonium halide solution containing the following (A), (B), and (D). (A), (B), and (D) can be those described above. (A) A quaternary ammonium ion represented by the following formula (1): (B) A halide ion (D) Water (In the formula, R １ , R ２ , R ３ , and R ４are each independently an alkyl group having 1 to 16 carbon atoms (preferably 1 to 8, more preferably 1 to 4), provided that R １ , R ２ , R ３ , and R ４ wherein one or more alkyl groups have 2 to 16 carbon atoms (preferably 2 to 8, more preferably 2 to 4), and R １ , R ２ , R ３ , and R ４ are not all the same alkyl group.)

[0047] Furthermore, when the photoresist developer contains tetramethylammonium ions, the method for producing the photoresist developer may include an electrolysis step A in which an aqueous quaternary ammonium halide solution containing tetramethylammonium ions, (B), and (D) is electrolyzed, and an electrolysis step B in which the aqueous quaternary ammonium halide solution containing (A), (B), and (D) is electrolyzed. The electrolysis step A produces an aqueous tetramethylammonium hydroxide solution, and the electrolysis step B produces an aqueous solution of the hydroxide of the quaternary ammonium ion represented by formula (1). The resulting aqueous tetramethylammonium hydroxide solution and the aqueous solution of the hydroxide of the quaternary ammonium ion represented by formula (1) are mixed to produce the photoresist developer.

[0048] The production of a photoresist developer by electrolysis can be achieved using an electrolytic cell having one or more cation exchange membranes disposed between an anode and a cathode, a source chamber for supplying a quaternary ammonium halide aqueous solution as a source, and a base chamber (cathode chamber) for producing a quaternary ammonium hydroxide aqueous solution. In this production method using an electrolytic cell, quaternary ammonium ions contained in the quaternary ammonium halide aqueous solution pass through the cation exchange membrane disposed on the cathode side during electrolysis. This results in the production of a quaternary ammonium hydroxide aqueous solution in the base chamber. While the above example illustrates the use of one or more cation exchange membranes, an electrolytic cell containing multiple membranes selected from the group consisting of cation exchange membranes, anion exchange membranes, and bipolar membranes (composite membranes consisting of a cation exchange membrane and an anion exchange membrane) may also be used, as long as it can produce a quaternary ammonium hydroxide aqueous solution.

[0049] At this time, halide ions, which are anions of the quaternary ammonium halide, move to the anode side, but some of the halide ions also move to the cathode side due to diffusion. For this reason, depending on the concentration of the liquid used as the raw material, halide ions of about 1 to several tens of ppm may be mixed into the aqueous quaternary ammonium hydroxide solution.

[0050] The method for producing a photoresist developer may include, prior to the electrolysis step, a preparation step of preparing an aqueous quaternary ammonium halide solution to be used as a raw material in the electrolysis step. The preparation step is not particularly limited, and for example, the aqueous quaternary ammonium halide solution can be prepared by producing an aqueous quaternary ammonium halide solution. Furthermore, the method for producing the aqueous quaternary ammonium halide solution is not particularly limited. For example, from the viewpoints of productivity and quality, a step of reacting a trialkylamine with an alkyl halide in ultrapure water to obtain a quaternary ammonium halide is preferred.

[0051] The trialkylamine and alkyl halide used as raw materials are not particularly limited as long as they can produce the quaternary ammonium ion represented by formula (1). Specifically, the alkyl groups contained in the trialkylamine and the alkyl halide may each have at least one alkyl group containing 2 to 16 carbon atoms (preferably 2 to 8, more preferably 2 to 4), and the remaining alkyl groups may each have 1 to 16 carbon atoms (preferably 1 to 8, more preferably 1 to 4). Furthermore, when the photoresist developer contains tetramethylammonium ions, the trialkylamine may contain trimethylamine, and the alkyl group contained in the alkyl halide may be a methyl group. Furthermore, the halide ion, which is the anion of the alkyl halide, may be the same as that described in (B) above. Because impurities contained in the quaternary ammonium halide diffuse into and become mixed into the aqueous quaternary ammonium hydroxide solution, it is preferable to use a high-purity quaternary ammonium halide. Specifically, the alcohol concentration in the aqueous quaternary ammonium halide solution is preferably 0.1 to 10,000 ppm by mass, more preferably 0.1 to 100 ppm by mass. The concentration of the amine is preferably 0.1 to 10,000 ppm by mass, and more preferably 0.1 to 100 ppm by mass.

[0052] The photoresist developer can develop an exposed photoresist layer. That is, the photoresist development method of the present invention may include a developing step of developing the exposed photoresist layer using the photoresist developer of the present invention. The developing step may be the same as the developing step in the semiconductor device manufacturing method described below. Furthermore, as described below, the photoresist layer contains a photosensitive resin. That is, the photoresist developer is preferably a developer for developing an exposed photoresist layer containing a photosensitive resin. The photosensitive resin may be photosensitive because the polymer contained in the photosensitive resin has photosensitivity, or the photosensitive resin may have photosensitivity due to the inclusion of a photosensitizer. For example, the polymer contained in the photosensitive resin may undergo a chemical or structural change upon exposure, or the photosensitizer that can be contained in the photosensitive resin may undergo a chemical or structural change upon exposure, or the change in the photosensitive material may cause a chemical or structural change in the photosensitive resin (chemically amplified photoresist). Known photosensitizers can be used. Another aspect of the present invention is the use of a photoresist developer for developing a photoresist layer containing a photosensitive resin.

[0053] A method for manufacturing a semiconductor device according to one embodiment of the present invention will be described below. Manufacturing of a semiconductor device using the photoresist developer of the present invention can be carried out according to a known method. For example, the method for manufacturing a semiconductor device includes an exposure step of irradiating a photoresist layer on a substrate with light through a photomask having a predetermined pattern, and a development step of developing the photoresist layer exposed in the exposure step to form a resist pattern corresponding to the pattern of the photomask, in which the exposed photoresist layer is developed using the photoresist developer in the development step.

[0054] In addition to the above steps, the semiconductor device manufacturing method may also include the following steps. For example, a photoresist layer may be formed by applying a coating liquid containing a photosensitive resin to a predetermined substrate surface and drying the coating liquid. The drying temperature in the formation step is not particularly limited, but may be, for example, 50 to 190°C, preferably 70 to 160°C. The drying time is also not particularly limited, but may be, for example, 30 to 150 seconds, preferably 60 to 120 seconds. The coating liquid contains, for example, a photosensitive resin and a solvent. The solvent is not particularly limited as long as it can dissolve the photosensitive resin. For example, an ester-based solvent such as propylene glycol monomethyl ether acetate or a ketone-based solvent can be used. The method for applying the coating liquid is not particularly limited, and known methods can be used, such as spin coating. The thickness of the photoresist layer is not particularly limited, but is preferably, for example, 1 nm to 20 μm.

[0055] Furthermore, the method for manufacturing a semiconductor device may include, after the development step, a cleaning step in which a rinsing liquid is used to clean and remove the developer containing the eluted resist components, and a drying step in which the semiconductor device obtained in the cleaning step is dried. The cleaning time in the cleaning step is not particularly limited, but may be, for example, 10 to 120 seconds, preferably 10 to 90 seconds. The temperature in the cleaning step is not particularly limited, but may be, for example, 10 to 40°C. As the rinsing liquid, known water such as ion-exchanged water can be used. The drying temperature in the drying step is not particularly limited, but may be, for example, 50 to 100°C. The drying time is not particularly limited, but may be, for example, 30 to 150 seconds.

[0056] Furthermore, when a chemically amplified photoresist is used, the method for manufacturing a semiconductor device preferably includes a heating step of heating the photoresist layer as needed to promote acid generation. The heating temperature is not particularly limited, but may be, for example, 70 to 110°C. This heating step is carried out after the exposure step. The heating time in the heating step is not particularly limited, but may be, for example, 1 to 10 minutes.

[0057] In the exposure step, the photoresist layer on the substrate is irradiated with light through a photomask having a predetermined pattern. The wavelength of the light is preferably selected according to the photosensitivity of the photoresist. To form a fine resist pattern, short-wavelength light such as excimer laser light is used. Exposure by electron beam or X-ray irradiation is also possible depending on the type of photoresist. Examples of light sources include mercury lamps used for g-line (436 nm), h-line (405 nm), and i-line (365 nm), excimer lasers used for KrF (248 nm) and ArF (193 nm), EUV (13.5 nm) light sources, and electron beam light sources. That is, the photoresist developer may be a photoresist developer for developing a photoresist layer exposed using one or more light sources selected from the group consisting of a mercury lamp, an excimer laser, an EUV light source, and an electron beam light source, or a photoresist developer for developing a photoresist layer exposed using one or more excimer lasers selected from the group consisting of a KrF excimer laser and an ArF excimer laser.

[0058] Another aspect of the present invention is use of a photoresist developer for developing an exposed photoresist layer. The above-mentioned light sources can be used for exposure. For example, the present invention may be use of a photoresist developer for developing a photoresist layer exposed using an excimer laser. Furthermore, the present invention is preferably use of a photoresist developer for developing a photoresist layer exposed using one or more excimer lasers selected from the group consisting of a KrF excimer laser and an ArF excimer laser.

[0059] The photoresist layer is a layer containing a photosensitive resin (photoresist). The photoresist is not particularly limited and may be a positive photoresist or a negative photoresist. A positive photoresist is a photosensitive resin whose exposed regions become soluble in a developer, while a negative photoresist is a photosensitive resin whose exposed regions become insoluble in a developer. Examples of positive photoresists include (meth)acrylic resins such as polymethyl (meth)acrylate, urethane resins such as polyurethane, phenolic resins such as novolac resins, styrene resins such as polyhydroxystyrene (PHS) resins, and resins having an aliphatic polycyclic skeleton. Among these, one or more resins selected from the group consisting of (meth)acrylic resins and styrene resins are preferred. These resins may be used alone or in combination of two or more. Examples of negative photoresists include polyvinyl cinnamate and mixtures of a resin having an unsaturated carbon bond and an azide compound.

[0060] As described above, examples of styrene resins include polyhydroxystyrene resins. In one embodiment of a photoresist containing a polyhydroxystyrene resin, a portion of the hydroxyl groups of the polyhydroxystyrene resin contained in the photoresist are preferably substituted with protecting groups. The introduction of protecting groups renders the photoresist insoluble in photoresist developer in unexposed regions. Furthermore, in exposed regions, a chemical reaction occurs in which the protecting groups are eliminated and replaced with hydroxyl groups, rendering the photoresist soluble in photoresist developer. In this case, when the molar mass of hydroxyl groups in the polyhydroxystyrene resin contained in the photoresist is taken as 100 mol, the molar mass of the protecting groups in the polyhydroxystyrene resin is preferably 75 to 300 mol, more preferably 90 to 200 mol. The protecting group is not particularly limited, and examples include an acetal group, a ketal group, a silyl group, a silyl ether group, and a tertiary alkyl ester group. The protecting group may have any substituent or a cyclic structure. Specific examples include a tert-butoxycarbonyl group, an isopropoxycarbonyl group, and a benzyloxycarbonyl group. Of these, a tert-butoxycarbonyl group is preferred.

[0061] In a dissolution rate evaluation test at 23°C for a photoresist layer containing a polyhydroxystyrene resin, the ratio of hydroxyl groups to tert-butoxycarbonyl groups in the polyhydroxystyrene resin is 70:30 on a mass basis, the photoresist layer is 200 nm thick, and the dissolution rate of the photoresist layer when using the photoresist developer of the present invention is preferably 110% or more, and more preferably 130% or more, of the dissolution rate of the photoresist layer when using a photoresist developer containing tetramethylammonium hydroxide. A dissolution rate of the photoresist layer in the above range when using the photoresist developer of the present invention indicates excellent solubility of the photoresist near the border of the photomask, where light-induced chemical reactions are less likely to proceed. As a result, a good pattern shape is likely to be obtained. The specific method for the dissolution rate evaluation test will be described later, and the temperature in the dissolution rate evaluation test refers to the temperature of the photoresist developer being evaluated. The upper limit of the dissolution rate is not particularly limited, and examples include 110 to 500%, 110 to 300%, and 130 to 200%. The dissolution rate can be determined, for example, by the alkyl group R in the quaternary ammonium ion represented by the formula (1). １ ~R ４ For example, the number of carbon atoms in R １ , R ２ , R ３ , and R ４ When a compound in which any three of the alkyl groups are methyl groups and the remaining alkyl group has 2 to 16 carbon atoms is used, the dissolution rate tends to be high. If the alkyl group in the lipophilic portion has too many carbon atoms, the dissolution rate of the resist layer will decrease due to adsorption inhibition, so the alkyl group in the lipophilic portion has 16 or less carbon atoms. The number of carbon atoms in the alkyl group is preferably 8 or less, more preferably 4 or less. In addition, the number of carbon atoms in R １ , R ２ , R ３ , and R ４ When any three of the above are methyl groups, a hydrophilic portion is formed relative to the lipophilic portion, which is preferable because it improves the wettability with the photoresist resin and can increase the dissolution rate.

[0062] As described above, the photoresist may be a (meth)acrylic resin. The structure of the (meth)acrylic resin is not particularly limited, but the (meth)acrylic resin preferably has a monomer unit represented by the following formula (D). Furthermore, the monomer units represented by the following formula (D) may be the same or different monomer units. In formula (D), Rx represents any protecting group, and Ry represents hydrogen or a methyl group.

[0063] The protecting group represented by Rx is not particularly limited as long as it is a functional group that is eliminated by exposure to light, and examples thereof include hydrocarbon groups having 3 to 12 carbon atoms (preferably 6 to 9 carbon atoms). The hydrocarbon group may be linear, branched, or cyclic. Among these, an alicyclic hydrocarbon group is preferred. The content of the monomer unit represented by formula (D) in the (meth)acrylic resin is not particularly limited, and may be 50 to 100 parts by mass, or may be 70 to 100 parts by mass.

[0064] Specifically, preferred are a tert-butoxycarbonyl group, a 2-alkyl-substituted adamantyloxycarbonyl group such as a 2-methyladamantyloxycarbonyl group, a 2-alkyl-substituted norbornyloxycarbonyl group such as a 2,6-carbolactonenorbornyl group, and a 2-pyranyloxycarbonyl group.

[0065] In the development step, the photoresist layer exposed in the exposure step is developed to form a resist pattern corresponding to the pattern of the photomask. In the method for manufacturing a semiconductor device of the present invention, the exposed photoresist layer is developed using the photoresist developer. That is, a resist pattern is formed on the substrate, and regions covered with the resist pattern and regions not covered with the resist pattern are formed. The photoresist layer is preferably developed, for example, by applying the photoresist developer of the present invention to the photoresist layer exposed in the exposure step.

[0066] The development of the exposed photoresist layer is not particularly limited except for the use of the photoresist developer. Known methods such as immersion, paddle development, and spray development can be used without particular limitation. The immersion method involves immersing a substrate, such as a silicon wafer, on which a photoresist layer has been formed in a developer for a certain period of time, followed by immersion in pure water and drying. The paddle development method involves dripping a developer onto the photoresist layer, leaving it to stand for a certain period of time, and then washing with pure water and drying. The spray development method involves spraying a developer onto the photoresist layer, washing with pure water, and drying. In this case, if the photoresist is a positive-type photoresist, the exposed regions of the photoresist layer that were exposed in the exposure step are removed. On the other hand, if the photoresist is a negative-type photoresist, the unexposed regions of the photoresist layer that were not exposed in the exposure step are removed. The temperature in the development step is not particularly limited, but may be, for example, 10 to 40°C, preferably 15 to 30°C. The time for the development step is not particularly limited, but may be, for example, 10 to 120 seconds, and preferably 10 to 90 seconds. Note that the term "semiconductor substrate" is a term used in the semiconductor device manufacturing process.

[0067] The method for manufacturing a semiconductor device preferably includes a processing step of processing an area of ​​a substrate having a resist pattern on its surface that is not covered by the resist pattern. The processing step is a step that follows the development step. By including the processing step in the method for manufacturing a semiconductor device, a semiconductor device having a patterned substrate can be obtained. As the processing method, a known method can be used, and examples thereof include etching such as wet etching or dry etching, and plating.

[0068] Examples will be given below to specifically explain the present invention, but the present invention is not limited to these. The evaluations carried out in the examples and comparative examples were determined by the following methods.

[0069] (Examples 1 to 7, Comparative Examples 1 to 3) [Photoresist Developer] Each aqueous solution of quaternary ammonium hydroxide was prepared to 0.26 mol / L to serve as a photoresist developer. The dissolution rate of the photoresist was evaluated using the method described below. Ethyltrimethylammonium hydroxide (ETMAH, prepared from raw materials) Propyltrimethylammonium hydroxide (PTMAH, prepared from raw materials) Butyltrimethylammonium hydroxide (BTMAH, prepared from raw materials) Tetramethylammonium hydroxide (TMAH, manufactured by Tokuyama) Tetraethylammonium hydroxide (TEAH, manufactured by Tokyo Chemical Industry Co., Ltd.) [Surfactants] Surfynol (registered trademark) 465 (manufactured by Nissin Chemical Industry Co., Ltd.)

[0070] [Preparation of Quaternary Ammonium Hydroxide Aqueous Solutions] ETMAH, PTMAH, and BTMAH were prepared according to the following procedure. A quaternary ammonium halide aqueous solution was prepared from the raw materials trialkylamine and alkyl halide, and then electrolysis was performed using this raw material to prepare a quaternary ammonium hydroxide aqueous solution. Specifically, in the case of ETMAH, trimethylamine and ethyl chloride were charged in a 1:1 molar ratio into a reaction vessel containing ultrapure water, and the reaction temperature was maintained at 60°C to prepare a 50% by mass ethyltrimethylammonium chloride aqueous solution. Unreacted trimethylamine and ethyl chloride, as well as by-product ethanol, were removed under reduced pressure until their concentrations were each less than 100 ppm. ETMAH was then prepared using the electrolytic cell shown in Figure 1. In Figure 1, 1 represents an anode, 2 represents a cathode, 3 represents a power source, 4 represents an anode chamber, 5 represents a raw material chamber, 6 represents an intermediate chamber, 7 represents a cathode chamber, 8 represents an anion exchange membrane, and 9 represents a cation exchange membrane.

[0071] A platinum-plated nickel plate was used as the cathode, a platinum-plated titanium plate as the anode, two Nafion N324 (manufactured by Chemours) cation exchange membranes, and ASE (manufactured by Astom) anion exchange membrane. 0.5N hydrochloric acid was circulated in the anode chamber, a 50% by mass aqueous solution of ethyltrimethylammonium chloride was circulated in the raw material chamber between the anion exchange membrane and the cathode-side cation exchange membrane, and ultrapure water was circulated in the intermediate chamber between the cathode chamber and the two cation exchange membranes. The current density was gradually increased until a final current density of 30 A / dm was achieved. ２ Electrolysis was carried out continuously while maintaining the temperature at 40°C. During the electrolysis, an aqueous solution of ethyltrimethylammonium chloride was replenished so that the ethyltrimethylammonium chloride concentration in the source chamber was maintained at 40 mass% or more. When the ETMAH concentration in the cathode chamber increased to 30 mass%, the electrolysis was terminated to obtain an aqueous ETMAH solution. This aqueous ETMAH solution was diluted with ultrapure water and used in Example 1 at the concentration shown in Table 1.

[0072] PTMAH and BTMAH were prepared in the same manner as ETMAH, except that propyl chloride and butyl chloride were used as the alkyl halides at the concentrations shown in Table 1. The surfactants shown in Table 1 were added to Examples 6 to 7 and Comparative Example 3. The amine concentrations in the photoresist developers of Examples 1 to 7 and Comparative Examples 1 to 3 were all less than 100 ppm by mass. The alcohol concentrations in the photoresist developers of Examples 1 to 7 and Comparative Examples 1 to 3 were all less than 100 ppm by mass. The calcium ions, sodium ions, potassium ions, chromium ions, nickel ions, iron ions, lead ions, and aluminum ions in the photoresist developers of Examples 1 to 7 and Comparative Examples 1 and 3 were all 0.1 ppb or less. The photoresist developer of Comparative Example 2 was purified with a cation exchange resin, reducing the calcium ions, sodium ions, potassium ions, chromium ions, nickel ions, iron ions, lead ions, and aluminum ions in the photoresist developer to 0.1 ppb or less.

[0073] [Evaluation Method] 1) Measurement of Halide Ion Concentration When the quaternary ammonium hydroxide concentration of the photoresist developer was 5% by mass or less, the photoresist developer was left as is, whereas when the concentration exceeded 5% by mass, the photoresist developer was diluted with ultrapure water to 5% by mass and passed through a 2.5 cc Onguard Cartridge IIH+ (manufactured by Thermo Fisher Scientific). The solution was then recovered, and anion analysis of the recovered solution was performed using an ion chromatograph (Integrion, manufactured by Thermo Fisher Scientific) to determine the halide ion concentration.

[0074] 2) Hydroxide ion concentration Neutralization titration with 0.1 mol / L hydrochloric acid was performed on 1 mL of the developer prepared in each of the Examples and Comparative Examples using a Hiranuma automatic titrator (COM-1700, manufactured by HIRANUMA). The hydroxide ion concentration of the photoresist developer was calculated from the amount of 0.1 mol / L hydrochloric acid required for neutralization.

[0075] 3) Evaluation of Dissolution Rate of Photoresist Layer The dissolution rate of the photoresist layer in the photoresist developer was evaluated using the QCM method (Quartz Crystal Microbalance Method). The QCM substrate was spin-coated with the photoresist resin described below and pre-baked at 90°C for 90 seconds to form a photoresist layer with a thickness of 200 nm. This photoresist layer was immersed in a photoresist developer at a temperature of 23°C, and the dissolution rate of the photoresist layer was evaluated. The dissolution rate was determined by the time required for the impedance value obtained by the QCM method to increase and then decrease. Since the viscosity of the interface decreases when the photoresist layer is completely dissolved, it can be determined that the shorter the time for the impedance to decrease, the faster the dissolution rate of the photoresist layer.

[0076] The photoresist resin used was a solution prepared in advance with a resin composition before exposure and a resin composition after exposure. Specifically, a resin (30% t-Boc-PHS) was prepared by protecting the hydroxyl groups (OH groups) of polyhydroxystyrene with tert-butoxycarbonyl groups (t-Boc groups) and substituting them so that the ratio of OH groups to t-Boc groups was 70:30 on a mass basis. This resin was then dissolved in propylene glycol monomethyl ether acetate (PGMEA) to prepare a solution. The dissolution rate was evaluated using 2.4% by mass (0.26M) TMAH as the standard and according to the following evaluation criteria. The results are shown in Table 1 as "dissolution rate." (Evaluation criteria) A: 130% or more of the dissolution rate of TMAH B: 110% or more to less than 130% of the dissolution rate of TMAH C: 90% or more to less than 110% of the dissolution rate of TMAH D: Less than 90% of the dissolution rate of TMAH

[0077] 4) Development Characteristics Evaluation Development characteristics were evaluated by forming patterns for each of the different resists A and B, and evaluating the resulting shapes. [Pattern Formation Using Resist A] 100 parts by weight of polyhydroxystyrene (weight average molecular weight 10,000) in which 50 mol% of the hydrogen atoms of the hydroxyl groups have been substituted with tert-butoxycarbonyl groups; 5 parts by weight of triphenylsulfonium hexafluoroantimonate; 0.2 parts by weight of triethanolamine; 400 parts by weight of propylene glycol monomethyl ether acetate (PGMEA). The prepared resist A was spin-coated onto a hexamethyldisilazane-treated silicon wafer using a spin coater and baked at 90°C for 90 seconds using a hot plate to obtain a resist film with a thickness of 0.6 μm. This film was exposed to a KrF excimer laser through a mask pattern (1:1 line and space with a line width of 260 nm) using a KrF exposure device. Thereafter, post-exposure baking was performed for 60 seconds at 110° C. Furthermore, the resist was developed for 30 seconds at 23° C. with an aqueous solution of quaternary ammonium hydroxide having the concentration shown in Table 1, rinsed with ultrapure water for 30 seconds, and dried to obtain a pattern shape.

[0078] [Pattern formation using resist B] 100 parts by weight of a copolymer (weight average molecular weight 14,000) containing a monomer unit represented by the above formula (2-1) and a monomer unit represented by the above formula (2-2) in a molar ratio of 50:50; 1.5 parts by weight of triphenylsulfonium trifluoromethanesulfonate; and 0.1 parts by weight of triethanolamine. The above materials were dissolved in a mixed solvent of 950 parts by weight of propylene glycol monomethyl ether acetate (PGMEA) and 100 parts by weight of γ-butyrolactone to obtain a positive resist solution. This resist solution was then applied to a silicon wafer using a spin coater and dried on a hot plate at 140°C (pre-bake) for 90 seconds to form a 250 nm resist layer. Next, using an ArF exposure device, ArF excimer laser light (193 nm) was irradiated through a mask pattern (1:1 line and space with a line width of 100 nm). Thereafter, the resist was subjected to post-exposure baking (PEB) at 130° C. for 90 seconds, followed by puddle development for 20 seconds with an aqueous solution of quaternary ammonium hydroxide having the concentration shown in Table 1, followed by rinsing with water for 60 seconds and drying.

[0079] [Evaluation of Shape] The state of the lines and spaces obtained by forming the pattern was observed using a scanning electron microscope (JSM-7800F Prime, manufactured by JEOL Ltd.), and the width of the exposed bottom portion was observed at 10 points, and the arithmetic mean value of the observed widths was calculated. The dimensional difference of the arithmetic mean value of the observed widths relative to the size of the mask pattern was calculated using the following formula. Evaluation was then performed according to the following criteria. The results are shown in Table 1 as "developed shape." (Dimensional difference (%)) = (Mask pattern size (nm) - arithmetic mean value of width (nm)) / Mask pattern size (nm) x 100 (Evaluation criteria) A: Dimensional difference less than 3% B: Dimensional difference 3% or more but less than 5% C: Dimensional difference 5% or more but less than 10% D: Dimensional difference 10% or more, or resist remained and the bottom portion was not visible

[0080] 5) Surface Tension Using a surface tensiometer DY-300 (manufactured by Kyowa Interface Science Co., Ltd.), the surface tension of the developers prepared in the Examples and Comparative Examples was measured at 25°C in accordance with JIS 2241 "Test method using a Wilhelmy surface tensiometer."

[0081] Example 8 The same photoresist developer as in Example 1 was used, except that the Cl concentration in Example 1 was changed to 210 ppm, and development characteristics were evaluated using resist A. As a result, the developed shape was rated B, the same as in Example 1, but the proportion of resist residue increased compared to Example 1.

[0082] Example 9 A photoresist developer similar to that used in Example 2 was used, except that the Cl concentration was changed to 85 ppm, and development characteristics were evaluated using resist A. As a result, the developed shape was rated A, similar to Example 1, but the proportion of resist residue increased compared to Example 2. In the table, in the dissolution rate and surface tension columns, "-" indicates that the data was not measured.

[0083] As shown in Table 1, ETMAH, PTMAH, and BTMAH exhibited faster dissolution rates than TMAH and superior development characteristics. During development, protective groups tended to remain near the mask in the exposed area. When TMAH alone was used, undissolved residues occurred on the sides of the exposed area, resulting in a narrower bottom width compared to the line width of the mask pattern. On the other hand, ETMAH, PTMAH, and BTMAH produced less undissolved residues on the sides of the exposed area, resulting in a bottom width closer to the line width of the mask pattern, resulting in a more rectangular pattern with sides nearly perpendicular to the bottom. Furthermore, when BTMAH and TMAH were mixed, less undissolved residues remained on the sides than when TMAH alone was used, resulting in a more rectangular pattern. Furthermore, it was found that the addition of a small amount of surfactant further reduced the undissolved residues.

[0084] The photoresist developer of the present invention can be used as a photoresist developer that produces a good pattern shape.

[0085] 1: Anode 2: Cathode 3: Power supply 4: Anode chamber 5: Raw material chamber 6: Intermediate chamber 7: Cathode chamber 8: Anion exchange membrane 9: Cation exchange membrane

Claims

1. A photoresist developer comprising the following components (A), (B), (C), and (D): (A) a quaternary ammonium ion represented by the following formula (1); (B) a halide ion; (C) a hydroxide ion; and (D) water. (In the formula, R １ , R ２ , R ３ , and R ４ are each independently an alkyl group having 1 to 16 carbon atoms, provided that R １ , R ２ , R ３ , and R ４ Among these, one or more alkyl groups have 2 to 16 carbon atoms, and R １ , R ２ , R ３ , and R ４ All of the alkyl groups may not be the same.

2. The photoresist developer according to claim 1, wherein the photoresist developer has a surface tension of 73.0 mN / m or less at 25°C.

3. R ​​in the above formula (1) １ , R ２ , and R ３ is a methyl group, and R ４ 3. The photoresist developer according to claim 1, wherein is an alkyl group having 2 to 16 carbon atoms.

4. The photoresist developer according to any one of claims 1 to 3, wherein the (B) halide ion is a chloride ion or a bromide ion.

5. A photoresist developer according to any one of claims 1 to 4, wherein the weight parts of said halide ions are 0.0000001 to 0.01 parts by weight when the weight of said hydroxide ions in said photoresist developer is 1 part by weight.

6. The photoresist developer according to any one of claims 1 to 5, further comprising one or more compounds selected from the group consisting of alcohols and amines.

7. The photoresist developer according to any one of claims 1 to 6, which is a photoresist developer for developing an exposed photoresist layer containing a photosensitive resin.

8. The photoresist developer according to any one of claims 1 to 7, which contains one or more metal ions selected from the group consisting of calcium ions, sodium ions, potassium ions, chromium ions, nickel ions, iron ions, lead ions and aluminum ions, and the content of each metal ion in the photoresist developer is independently 1 ppb or less.

9. The photoresist developer according to any one of claims 1 to 8, which is a photoresist developer for developing a photoresist layer exposed with one or more excimer lasers selected from the group consisting of KrF excimer lasers and ArF excimer lasers.

10. The photoresist developer according to any one of claims 1 to 9, wherein, in a dissolution rate evaluation test at 23°C of a photoresist layer containing a polyhydroxystyrene resin, a ratio of hydroxyl groups to tert-butoxycarbonyl groups in the polyhydroxystyrene resin is 70:30 on a substance amount basis, the photoresist layer has a thickness of 200 nm, and the dissolution rate of the photoresist layer when using the photoresist developer is 110% or more of the dissolution rate of the photoresist layer when using a photoresist developer containing tetramethylammonium hydroxide.

11. The photoresist developer according to any one of claims 1 to 10, further comprising a surfactant, the concentration of the surfactant in the photoresist developer being less than 100 ppm by mass.

12. The photoresist developer according to any one of claims 1 to 11, further comprising tetramethylammonium ions.

13. A photoresist developing method, comprising a developing step of developing an exposed photoresist layer with the photoresist developer according to any one of claims 1 to 12.

14. A method for manufacturing a semiconductor device, comprising: an exposure step of irradiating a photoresist layer on a substrate with light through a photomask having a predetermined pattern; and a development step of developing the photoresist layer exposed in the exposure step to form a resist pattern corresponding to the pattern of the photomask, wherein in the development step, the exposed photoresist layer is developed using a photoresist developer according to any one of claims 1 to 12.

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