Photoresist developing solution

Abstract

A photoresist developer containing (A), (B), (C) and (D): (A) quaternary ammonium ions represented by formula (1), (B) halide ions, (C) hydroxyl ions, and (D) water. (In the formula, R1, R2, R3, and R4 are each independently an alkyl group having 1-16 carbon atoms, and among R1, R2, R3, and R4, the number of carbon atoms of one or more alkyl groups is 2-16, and R1, R2, R3, and R4 are not all the same alkyl groups).

Description

Technical Field

[0001] This invention relates to photoresist developer. Background Technology

[0002] Quaternary ammonium compounds are used in phase transfer catalysts, surfactants, disinfectants, etc. Among quaternary ammonium compounds, tetramethylammonium hydroxide, in particular, is an organic base exhibiting strong alkalinity and is used in alkaline aqueous solutions for semiconductors in cleaning, etching, and developing solutions during semiconductor manufacturing.

[0003] For example, Patent Document 1 discloses an aqueous solution of tetramethylammonium hydroxide with a metal ion and halide ion content of 2.35% by weight, which is a specified value.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 4-226466 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, the inventors have discovered that when using an aqueous solution of tetramethylammonium hydroxide (hereinafter also referred to as TMAH) as the photoresist developer, the photoresist developer sometimes has insufficient ability to develop the photoresist layer. If the ability to develop the photoresist layer is insufficient, residue of the photoresist layer will remain on the substrate during development, and sometimes the pattern shape will become poor.

[0009] Therefore, the object of the present invention is to provide a photoresist developer with high development capability and good pattern shape of photoresist layers. Another object is to provide a photoresist development method with good pattern shape. Furthermore, the object of the present invention is to provide a method for manufacturing a semiconductor device with good pattern shape.

[0010] Solution for solving the problem

[0011] The inventors conducted repeated and in-depth research to obtain a photoresist developer with good pattern shape. The results showed that if a photoresist developer containing specific quaternary ammonium ions, halide ions, hydroxide ions, and water is used, the pattern shape can be improved, thus completing this invention.

[0012] That is, the structure of the present invention is as described below.

[0013] Item 1 A photoresist developer comprising the following (A), (B), (C) and (D):

[0014] (A) The quaternary ammonium ion shown in formula (1) below,

[0015] (B) Halogen ions,

[0016] (C) hydroxide ions,

[0017] (D) Water,

[0018]

[0019] In equation (1), R 1 R 2 R 3 and R 4 Each is an alkyl group having 1 to 16 carbon atoms, wherein R 1 R 2 R 3 and R 4 In this context, the number of carbon atoms in one or more alkyl groups is 2 to 16, and R 1 R 2 R 3 and R 4 Not all of them are the same alkyl group.

[0020] Item 2 The photoresist developer according to Item 1, wherein the surface tension of the photoresist developer is less than 73.0 mN / m at 25°C.

[0021] Item 3. Photoresist developer according to Item 1 or 2, wherein R of formula (1) 1 R 2 and R 3 For methyl, R in formula (1) 4 It is an alkyl group with 2 to 16 carbon atoms.

[0022] Item 4. Photoresist developer according to any one of items 1 to 3, wherein the (B) halide ion is a chloride ion or a bromide ion.

[0023] Item 5. Photoresist developer according to any one of items 1 to 4, wherein when the weight of the hydroxide ions in the photoresist developer is set to 1 part by weight, the weight of the halide ions is 0.0000001 to 0.01 parts by weight.

[0024] Item 6. The photoresist developer according to any one of items 1 to 5 further comprises one or more compounds selected from the group consisting of alcohols and amines.

[0025] Item 7. Photoresist developer according to any one of items 1 to 6, which is a photoresist developer for developing a photoresist layer containing a photosensitive resin and exposed.

[0026] Item 8. A photoresist developer according to any one of items 1 to 7, wherein 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 the content of each metal ion in the photoresist developer is independently less than 1 ppb.

[0027] Item 9. A photoresist developer according to any one of items 1 to 8, used for developing a photoresist layer exposed using one or more excimer lasers selected from the group consisting of KrF excimer lasers and ArF excimer lasers.

[0028] Item 10. The photoresist developer according to any one of items 1 to 9, wherein, in the dissolution rate evaluation test at a temperature of 23°C for the photoresist layer containing polyhydroxystyrene resin,

[0029] The ratio of hydroxyl groups to tert-butoxycarbonyl groups in the polyhydroxystyrene resin is 70:30 on a mass basis.

[0030] The thickness of the photoresist layer is 200 nm.

[0031] The dissolution rate of the photoresist layer when using the aforementioned photoresist developer is 110% or more higher than the dissolution rate of the photoresist layer when using a photoresist developer containing tetramethylammonium hydroxide.

[0032] Item 11 The photoresist developer according to any one of items 1 to 10 further comprises a surfactant, wherein the concentration of the surfactant in the photoresist developer is less than 100 ppm by mass.

[0033] Item 12 The photoresist developer according to any one of items 1 to 11 further comprises tetramethylammonium ions.

[0034] Item 13 A photoresist development method, comprising a development step of developing an exposed photoresist layer using the photoresist developer solution described in any one of Items 1 to 12.

[0035] Item 14 A method for manufacturing a semiconductor device, comprising:

[0036] In the exposure process, light is irradiated onto the photoresist layer on the substrate through a photomask with a specified pattern; and

[0037] The developing process involves developing the photoresist layer exposed in the exposure process to form a resist pattern corresponding to the pattern of the photomask.

[0038] In the development process, the photoresist developer described in any one of items 1 to 12 is used to develop the exposed photoresist layer.

[0039] The effects of the invention

[0040] According to the present invention, a photoresist developer with well-defined patterned shapes is provided. Furthermore, a photoresist development method with well-defined patterned shapes is provided. Moreover, a method for manufacturing a semiconductor device with well-defined patterned shapes is provided. Attached Figure Description

[0041] Figure 1 This is an explanatory diagram showing an electrolytic cell. Detailed Implementation

[0042] The embodiments of the present invention will be described in detail below, but the present invention is not limited to these contents as long as it does not depart from its spirit. In addition, the present invention can be implemented in any way without departing from its spirit.

[0043] In this specification, the numerical range represented by "~" refers to the range of values ​​recorded before and after "~" as the lower and upper limits. "A~B" means above A and below B. Furthermore, when numerical ranges are recorded in stages, the upper and lower limits of each numerical range can be arbitrarily combined.

[0044] In addition, in this specification, the description of (meth)acrylic resins refers to methacrylic resins and / or acrylic resins. Furthermore, monomer units refer to the form in which monomeric substances in the polymer have undergone reaction.

[0045] The photoresist developer of the present invention comprises the following (A), (B), (C) and (D).

[0046] (A) The quaternary ammonium ion represented by the following formula (1)

[0047] (B) Halide ions

[0048] (C) Hydroxide ions

[0049] (D) Water

[0050]

[0051] (where R) 1 R 2 R 3 and R 4 Each is independently an alkyl group having 1 to 16 carbon atoms (preferably 1 to 8, more preferably 1 to 4), wherein R 1 R 2 R 3 and R4 In this context, the number of carbon atoms in one or more alkyl groups is 2 to 16 (preferably 2 to 8, more preferably 2 to 4), and R 1 R 2 R 3 and R 4 Not all of them are the same alkyl group.

[0052] By including the quaternary ammonium ions shown in formula (1) in the photoresist developer, the pattern shape is more easily improved compared to using an aqueous solution of tetramethylammonium hydroxide as the photoresist developer. The reason for the improved pattern shape is not yet certain, but the inventors conjecture as follows.

[0053] In photolithography using photoresist developer, a photoresist layer disposed on a substrate is exposed to light through a photomask with a predetermined pattern. During this process, the photoresist in the exposed areas of the photoresist layer undergoes a chemical reaction due to the light. Conversely, the photoresist in the unexposed areas of the photoresist layer does not undergo a chemical reaction. The reactivity and solubility in solvents change between the chemically reacted and unreacted photoresist, thus altering its developability. The exposed photoresist layer is then developed using a photoresist developer, thereby forming a resist pattern corresponding to the photomask.

[0054] In this way, the photoresist contained in the exposed area undergoes a chemical reaction due to light. However, this chemical reaction is more difficult to occur near the boundaries of the photomask than near the center. Therefore, for example, when the photoresist is a positive photoresist, the photoresist near the boundaries of the photomask cannot be sufficiently dissolved by the developer, and residue remains on the substrate, resulting in poor pattern shape.

[0055] On the other hand, in the quaternary ammonium ion shown in the above formula (1), R 1 R 2 R 3 and R 4 Each is independently an alkyl group having 1 to 16 carbon atoms and R 1 R 2 R 3 and R 4 Not all of them are the same alkyl group, and R 1 R 2 R 3 and R 4The alkyl group in the formula (1) has 2 to 16 carbon atoms, thus exhibiting an asymmetric shape centered on the nitrogen atom, and at least one alkyl group has 2 to 16 carbon atoms. Therefore, in the quaternary ammonium ion shown in formula (1) above, the longer carbon portion of the alkyl group becomes oleophilic. As a result, for example, in the case of a positive photoresist, the affinity for portions that are difficult to undergo exposure-based chemical reactions is increased. Consequently, the contact between the developer and the photoresist is improved, and even photoresists near the boundaries of the photomask where the chemical reaction has not been fully carried out are considered to be able to dissolve sufficiently, including the effect of polarity on the affinity of the developer.

[0056] As a result, residues are less likely to remain during development, resulting in a good pattern shape.

[0057] R 1 ~R 4 When the number of carbon atoms exceeds the above range, the lipophilicity sometimes becomes too high, and the development speed decreases. Furthermore, based on the above viewpoint, R... 1 R 2 R 3 and R 4 In this embodiment, the number of carbon atoms in one or more alkyl groups is preferably 2 to 16, more preferably 3 to 16, further preferably 3 to 8, and most preferably 3 to 4.

[0058] In the above formula (1), R 1 R 2 R 3 and R 4 Not all of them are the same alkyl group. When expressed in another way, it is preferred to be the compound shown in (1) to (3) below.

[0059] (1) R 1 R 2 R 3 and R 4 A compound in which any three alkyl groups are the same and the remaining one is a different alkyl group.

[0060] (2) R 1 R 2 R 3 and R 4 A compound in which any two alkyl groups are the same and the remaining two are different alkyl groups (the remaining two can be the same or different).

[0061] (3) R 1 R 2 R 3 and R 4 Compounds consisting entirely of different alkyl groups

[0062] In the case of (1) above, the following can be listed: R 1 R 2 R 3 and R 4 The compound is defined as follows: any three of the first three are alkyl groups with the same number of carbon atoms (1-16), the remaining one is an alkyl group with the same number of carbon atoms (1-16), and the remaining one is a different alkyl group from the first three; any one of the first three or the remaining one is a compound with the number of carbon atoms (2-16). The R in formula (1) above... 1 R 2 R 3 and R 4 In this configuration, three of the groups are identical, and the remaining group is an alkyl group with 2 to 16 carbon atoms, different from the first group. In this case, the compound represented by formula (1) has two alkyl groups. In this configuration, R is preferred. 1 R 2 R 3 and R 4 A compound in which any three of the atoms are methyl groups and the remaining alkyl group is an alkyl group with 2 to 16 carbon atoms. R 1 R 2 R 3 and R 4 When any three of the compounds are methyl groups and the remaining compound has 2 to 16 carbon atoms, it readily functions as a surfactant, as described later. More preferably, the remaining alkyl group is a compound with 2 to 8 carbon atoms, and even more preferably, a compound with 2 to 4 carbon atoms. Furthermore, it is also preferable that the remaining alkyl group is a compound with 3 to 16 carbon atoms, more preferably, a compound with 3 to 8 carbon atoms, and even more preferably, a compound with 3 to 4 carbon atoms. If the composition falls within the above range, the pattern shape tends to be better.

[0063] In the case of (2) above, the following can be listed: R 1 R 2 R 3 and R 4 The compound is a compound in which any two of the first two are alkyl groups with the same number of carbon atoms (1 to 16), and the remaining two are alkyl groups with the same number of carbon atoms (1 to 16) that are different from the first two; the remaining two are alkyl groups that are the same as or different from each other; and either the first two or the remaining two are compounds with the same number of carbon atoms (2 to 16). In this case, the compound shown in formula (1) has two or three alkyl groups. In this manner, R is preferred. 1 R 2 R 3 and R 4 A compound in which any two of the terms are methyl groups and the remaining two are alkyl groups with 2 to 16 carbon atoms. R 1 R 2 R 3 and R 4When either of the two alkyl groups is methyl, it readily functions as a surfactant as described later. More preferably, the remaining two alkyl groups are compounds with 2 to 8 carbon atoms, and even more preferably compounds with 2 to 4 carbon atoms.

[0064] In the case of (3) above, the following can be listed: R 1 R 2 R 3 and R 4 All of these compounds are different alkyl groups, and at least one of them has 2 to 16 carbon atoms. In this case, the compound shown in formula (1) has four alkyl groups. In this manner, R is preferred. 1 R 2 R 3 and R 4 A compound in which any one of the atoms is methyl and the remaining three are alkyl groups having 2 to 16 carbon atoms. R 1 R 2 R 3 and R 4 When any one of them is methyl, it readily functions as a surfactant as described later. More preferably, the remaining three alkyl groups are compounds with 2 to 8 carbon atoms, and even more preferably compounds with 2 to 4 carbon atoms.

[0065] Specific examples of the quaternary ammonium ions shown in formula (1) above include ethyltrimethylammonium ion, diethyldimethylammonium ion, triethylmethylammonium ion, propyltrimethylammonium ion, butyltrimethylammonium ion, etc. One or more of these quaternary ammonium ions may be used.

[0066] The halide ion is not particularly limited, but if specific examples are given, one or more can be selected from the group consisting of chloride ions, bromide ions, and iodide ions. In addition, chloride ions or bromide ions are preferred.

[0067] When the weight of hydroxide ions in the photoresist developer is set to 1 part by weight, the weight of halide ions is not particularly limited, but 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 of halide ions varies considerably depending on the manufacturing method of the photoresist developer, especially by using an electrolytic manufacturing method, which can prepare a solution with reduced halide ions. Furthermore, adjustments can be made by changing conditions such as the structure of the electrolytic cell, the selection of the cation exchange membrane, and the current density.

[0068] If the photoresist developer contains a large number of halide ions, these halide ions may sometimes remain on the semiconductor surface during the development of the photoresist layer. In such cases, dross may sometimes form during development, reducing the physical properties of the semiconductor.

[0069] When the weight parts of halide ions are within the above range, the pattern shape during development becomes easier to improve when using photoresist developer.

[0070] The weight fraction of halide ions in photoresist developers can be analyzed using ion chromatography, especially when the photoresist developer is at a high concentration, where analysis based on neutralization is effective. Specifically, before introducing the photoresist developer into an anion chromatograph, the cations in the photoresist developer are exchanged with hydrogen ions to convert hydroxide ions into water. This removes hydroxide ions. Furthermore, concentration improves sensitivity. Using this method, the concentration of low-halide ions can be determined.

[0071] Photoresist developer contains hydroxide ions. Photoresist developer containing quaternary ammonium ions and hydroxide ions as shown in formula (1) above can also be said to mean: photoresist developer contains quaternary ammonium hydroxide (hydroxide of quaternary ammonium ions as shown in formula (1)) containing quaternary ammonium ions as shown in formula (1) above and containing hydroxide ions.

[0072] It can be used as a photoresist developer by containing quaternary ammonium ions as shown in formula (1).

[0073] The concentrations of quaternary ammonium ions and hydroxide ions shown in the above formula (1) in the photoresist developer are not particularly limited, but it is preferable to manufacture quaternary ammonium hydroxide at 1.0 to 65.0% by mass. For example, it is more preferable to use 1.0 to 10.0% by mass as quaternary ammonium hydroxide, and even more preferable to use 1.0 to 7.0% by mass. In addition, it is more preferable to use 1.0 to 4.5% by mass.

[0074] Furthermore, as a quaternary ammonium hydroxide, it is preferably used at a molar concentration of 0.10 to 1.0 mol / L, more preferably at 0.10 to 0.50 mol / L, and even more preferably at 0.10 to 0.33 mol / L.

[0075] Furthermore, a high-concentration photoresist developer containing a high concentration of quaternary ammonium ions as shown in formula (1) can also be diluted for use. By producing a high concentration, the volume during transportation can be reduced, thus suppressing transportation costs. In addition, even if contamination occurs during container filling or transportation of the photoresist developer, dilution can correspondingly reduce the impact of contamination compared to the undiluted case.

[0076] The concentration of the quaternary ammonium hydroxide shown in formula (1) in the high-concentration photoresist developer solution before dilution is preferably 10.0 to 50.0% by mass, more preferably 20.0 to 40.0% by mass. The concentration of quaternary ammonium hydroxide can be confirmed by acid-based neutralization titration or the like.

[0077] Furthermore, the concentration of the quaternary ammonium ions represented by the above formula (1) in the photoresist developer is preferably set to 0.8 to 52.9% by mass. In addition, it is more preferably set to 0.8 to 8.2% by mass, and even more preferably set to 0.8 to 5.7% by mass.

[0078] In addition, the concentration of the quaternary ammonium hydroxide represented by formula (1) in the high-concentration photoresist developer is preferably set to 8.0 to 40.7% by mass, more preferably 16.2 to 32.5% by mass.

[0079] Furthermore, the concentration of hydroxide ions in the photoresist developer is preferably set to 0.15 to 12.2% by mass. More preferably, it is set to 0.15 to 1.9% by mass, and even more preferably, it is set to 0.15 to 1.3% by mass.

[0080] In addition, the concentration of hydroxide ions in the high-concentration photoresist developer is preferably set to 1.9 to 9.4% by mass, more preferably 3.7 to 7.5% by mass.

[0081] The photoresist developer contains water. The form of water is not particularly limited, and any known type of water can be used; however, ultrapure water with reduced metal impurities is particularly preferred. Furthermore, the water content in the photoresist developer is not particularly limited, but is preferably 90.0 to 99.0% by mass, more preferably 93.0 to 99.0% by mass, and even more preferably 95.5 to 99.0% by mass.

[0082] In addition, the photoresist developer may contain one or more compounds selected from the group consisting of alcohols and amines. The concentration of 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, more preferably 0.1 to 100 ppm by mass.

[0083] There are no particular limitations on the alcohol used; any known alcohol 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. Furthermore, there are no particular limitations on the functionality of the alcohol; monohydric alcohols or alcohols with two or more carbon atoms can be used. However, from the viewpoint that a long chain could potentially cause adsorption hindrance during development, alcohols with 16 or fewer carbon atoms (more preferably 2 to 8, and even more preferably 2 to 4) are preferred.

[0084] There are no particular limitations on the amine used; any known amine can be used. Examples include primary amines such as methylamine, secondary amines such as dimethylamine, and tertiary amines such as trimethylamine. Furthermore, there are no particular limitations on the functionality of the amine; monoamines or amines with two or more carbon atoms can be used. From the viewpoint that a long chain could potentially cause adsorption hindrance during development, amines with 16 or fewer carbon atoms (more preferably 2 to 8, and even more preferably 2 to 4) are preferred.

[0085] The photoresist developer preferably 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 below a specific concentration. More preferably, the concentrations of chromium ions, nickel ions, iron ions, and aluminum ions are each below a specific concentration. By reducing the amount of these metal ions, metal contamination on the substrate surface after development is reduced, and the semiconductor failure rate is easily lowered.

[0086] Furthermore, the content of each metal ion in the photoresist developer is preferably 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 and can 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.

[0087] The concentration of metal ions can be determined by ICP-MS (inductively coupled plasma mass spectrometry).

[0088] Metal ions can sometimes be introduced due to contamination from raw materials, contact points, etc. Therefore, when the content of various metal ions is high, it can be reduced by purification using ion exchange resins or the like.

[0089] The photoresist developer is also preferably low in toxicity. For example, when the photoresist developer contains quaternary ammonium ions as shown in formula (1) above, it is less toxic than when an aqueous solution of tetramethylammonium hydroxide is used as the photoresist developer.

[0090] For the toxicity evaluation of photoresist developer solutions, in the OECD-based acute oral toxicity test on rats, the median lethal dose (LD50) value, calculated using quaternary ammonium hydroxide as 100% by mass, is preferably greater than 50 mg / kg. This results in higher safety during use and makes it easier to achieve a low environmental impact. Furthermore, in the GHS classification, an LD50 value of 50 mg / kg or less corresponds to Category 2, with stricter restrictions during storage and transportation; and a value of 5 mg / kg or less corresponds to Category 1, becoming even more stringent. Therefore, an LD50 value greater than 50 mg / kg is preferred. An LD50 value greater than 50 mg / kg and less than 10,000 mg / kg is more preferred, greater than 300 mg / kg and less than 10,000 mg / kg is even more preferred, and more than 2,000 mg / kg and less than 10,000 mg / kg is particularly preferred.

[0091] The LD50 value can be adjusted by changing the type of quaternary ammonium ion shown in the above formula (1).

[0092] From the perspective of toxicity, for example, it is preferable to use R in the above formula (1). 1 R 2 and R 3 Alkyl groups with 1 carbon atom, R 4 It is a quaternary ammonium ion of 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 even more preferred.

[0093] In addition, the photoresist developer may contain a surfactant. Preferably, the concentration of the surfactant in the photoresist developer is less than 100 ppm by mass. Alternatively, the photoresist developer may not contain a surfactant.

[0094] The quaternary ammonium ions represented by formula (1) contained in the above-mentioned photoresist developer have an asymmetric shape centered on the nitrogen atom, and R 1 R 2 R 3 and R 4 The alkyl group in the formula has 2 to 16 carbon atoms, and is therefore considered to be able to act as a surfactant. Specifically, the part with the longer number of carbon atoms in the alkyl group is lipophilic, while the part with the shorter number of carbon atoms is hydrophilic. Therefore, it is believed that the quaternary ammonium ion shown in the above formula (1) has both lipophilic and hydrophilic parts in its ionic structure, and thus acts as a surfactant.

[0095] Therefore, photoresist developers can be completely free of surfactants, or if they are present, their concentration can be as low as 100 ppm by mass. More preferably, the concentration of the surfactant is less than 50 ppm by mass, further preferably less than 30 ppm by mass, and particularly preferably less than 10 ppm by mass. By eliminating the surfactants contained in the photoresist developer, or even if the surfactant is present, its concentration is less than 100 ppm by mass, for example, foaming of the photoresist developer or impurities from the surfactant can be suppressed. Furthermore, when quaternary ammonium hydroxide is recovered from used developer through separation, purification, etc., and reused, a surfactant needs to be added again when it is required as a developer. In this case, if the surfactant concentration is low, the amount of surfactant added again can be suppressed. Additionally, when the photoresist developer does not contain surfactants, the recovered liquid can be used directly as a developer.

[0096] There is no specific lower limit for the surfactant concentration, but from the viewpoint of achieving the aforementioned effects, a concentration of 0.01 ppm by mass or more is preferred, and more preferably 0.1 ppm by mass or more. That is, the surfactant concentration can be, for example, 0.01 ppm by mass or more but less than 100 ppm by mass, 0.01 ppm by mass or more but less than 50 ppm by mass, 0.01 ppm by mass or more but less than 30 ppm by mass, 0.01 ppm by mass or more but less than 10 ppm by mass, or 0.1 ppm by mass or more but less than 10 ppm by mass.

[0097] As a surfactant, it is a compound having both a hydrophilic group and a hydrophobic group (lipophilic group) in one molecule, such as nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.

[0098] It should be noted that surfactants are compounds different from those mentioned above that may be contained in photoresist developers.

[0099] Photoresist developers can contain tetramethylammonium ions. The inventors have discovered that when the photoresist developer contains only tetramethylammonium ions as quaternary ammonium ions, a large amount of surfactant is sometimes required. The reason for this is presumed to be as follows.

[0100] For example, when a photoresist developer contains quaternary ammonium ions, and these quaternary ammonium ions are tetramethylammonium ions, the quaternary ammonium ions only have methyl groups with a small number of carbon atoms. As a result, the tetramethylammonium ion as a whole becomes hydrophilic. That is, tetramethylammonium does not exhibit the effects of a surfactant.

[0101] However, as described above, the quaternary ammonium ions represented by formula (1) contained in the photoresist developer of the present invention are considered to act as surfactants themselves. Therefore, even when tetramethylammonium, which does not exhibit the effect of a surfactant, is included, the amount of surfactant can be reduced.

[0102] Furthermore, by including the quaternary ammonium ions shown in formula (1) and also tetramethylammonium ions in the photoresist developer, the developing performance of the photoresist developer can be easily improved. As mentioned above, it is believed that the quaternary ammonium ions shown in formula (1) also act as surfactants. Therefore, even when tetramethylammonium is included, the developing performance can be easily improved. In this case, as mentioned above, the photoresist developer may also not contain surfactants.

[0103] When a photoresist developer contains tetramethylammonium ions, the photoresist developer contains both tetramethylammonium ions and hydroxide ions. The statement that a photoresist developer contains both tetramethylammonium ions and hydroxide ions can also be interpreted as: the photoresist developer contains tetramethylammonium hydroxide, which contains both tetramethylammonium ions and hydroxide ions.

[0104] There is no particular limitation on the concentration of tetramethylammonium ions in the photoresist developer, but it is preferable to manufacture it as tetramethylammonium hydroxide at a concentration of 1.0 to 30.0% by mass. For example, it is more preferable to use it as tetramethylammonium hydroxide at a concentration of 0.1 to 5.0% by mass, and even more preferably at a concentration of 0.5 to 3.0% by mass.

[0105] Furthermore, tetramethylammonium hydroxide is preferably used at a molar concentration of 0.01 to 0.55 mol / L, more preferably at 0.05 to 0.33 mol / L, and even more preferably at 0.1 to 0.27 mol / L.

[0106] Furthermore, the concentration of tetramethylammonium ions in the photoresist developer is preferably set to 0.08 to 4.0% by mass. More preferably, it is set to 0.4 to 2.4% by mass, and even more preferably, it is set to 0.8 to 2.0% by mass.

[0107] The total concentration of tetramethylammonium ions and quaternary ammonium ions as shown in formula (1) in the photoresist developer is preferably 0.5 to 6.0% by mass. More preferably, it is 1.0 to 5.0% by mass, and even more preferably, it is 1.2 to 4.0% by mass.

[0108] The total concentration of tetramethylammonium hydroxide and hydroxide of quaternary ammonium ions represented by formula (1) in the photoresist developer is preferably 0.4 to 5.0% by mass. More preferably, it is 0.8 to 4.0% by mass, and even more preferably, it is 1.0 to 3.2% by mass.

[0109] The total concentration of tetramethylammonium ions and quaternary ammonium ions as shown in formula (1) in the high-concentration photoresist developer is preferably 10.0 to 50.0% by mass. More preferably, it is 15.0 to 40.0% by mass, and even more preferably, it is 20.0 to 30.0% by mass.

[0110] As described above, it is believed that the quaternary ammonium ions represented by formula (1) also act as surfactants. As a result, the surface tension of the photoresist developer is reduced compared to the aqueous solution of tetramethylammonium hydroxide. Consequently, the wettability of the photoresist during development is easily improved. When the photoresist developer contains tetramethylammonium ions, the reduced surface tension compared to the aqueous solution of tetramethylammonium hydroxide leads to improved development characteristics.

[0111] Surface tension was measured using a DY-300 surface tension meter (manufactured by Kyowa Interface Chemical 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. Measurements were performed according to JIS 2241, "Test Method Using a Wilhelmi Surface Tensiometer".

[0112] The photoresist developer of this invention has a high ability to develop photoresist layers and produces good pattern shapes.

[0113] It should be noted that the photoresist developer of the present invention may appropriately contain known additives used in conventional developers, without impairing the effects of the present invention. Examples of such additives include wetting agents, stabilizers, and dissolving agents. They may be added individually or in combination of two or more.

[0114] The manufacturing method of the photoresist developer is not particularly limited. From the viewpoint of suppressing halide ion concentration, it is preferable to obtain it by electrolysis of an aqueous quaternary ammonium halide solution. That is, it is preferable to include an electrolysis step that electrolyzes the aqueous quaternary ammonium halide solution. Specifically, it is preferable to include an electrolysis step that electrolyzes an aqueous quaternary ammonium halide solution containing (A), (B), and (D) below. (A), (B), and (D) can be the substances described above.

[0115] (A) The quaternary ammonium ion represented by the following formula (1)

[0116] (B) Halide ions

[0117] (D) Water

[0118]

[0119] (where R) 1 R 2 R 3 and R4 Each is independently an alkyl group having 1 to 16 carbon atoms (preferably 1 to 8, more preferably 1 to 4), wherein R 1 R 2 R 3 and R 4 In this context, the number of carbon atoms in one or more alkyl groups is 2 to 16 (preferably 2 to 8, more preferably 2 to 4), and R 1 R 2 R 3 and R 4 Not all of them are the same alkyl group.

[0120] Furthermore, when the photoresist developer contains tetramethylammonium ions, the method for manufacturing the photoresist developer may include: an electrolysis step A, which electrolyzes an aqueous solution of a quaternary ammonium halide containing tetramethylammonium ions, (B) and (D) above; and an electrolysis step B, which electrolyzes an aqueous solution of a quaternary ammonium halide containing (A), (B) and (D) above. Electrolysis step A yields an aqueous solution of tetramethylammonium hydroxide, and electrolysis step B yields an aqueous solution of the hydroxide of the quaternary ammonium ions shown in formula (1). Then, by mixing the obtained aqueous solution of tetramethylammonium hydroxide with the aqueous solution of the hydroxide of the quaternary ammonium ions shown in formula (1), a photoresist developer can be obtained.

[0121] An electrolytic cell can be used to manufacture photoresist developer using electrolysis. This cell has one or more cation exchange membranes disposed between the anode and cathode, and includes a feed chamber for supplying an aqueous quaternary ammonium halide solution as raw material and an alkali chamber (cathode chamber) for generating an aqueous quaternary ammonium hydroxide solution. In the manufacturing method using this electrolytic cell, during electrolysis, quaternary ammonium ions contained in the aqueous quaternary ammonium halide solution pass through the cation exchange membrane disposed on the cathode side. This generates an aqueous quaternary ammonium hydroxide solution in the alkali chamber.

[0122] The above example is an example of configuring more than one cation exchange membrane, but as long as an aqueous solution of quaternary ammonium hydroxide can be generated, an electrolyzer with multiple membranes selected from the group consisting of cation exchange membranes, anion exchange membranes and bipolar membranes (composite membranes composed of cation exchange membranes and anion exchange membranes) can be used.

[0123] At this point, the halide ions, which are anions of quaternary ammonium halides, move towards the anode side, but some halide ions also move towards the cathode side due to diffusion. Therefore, although it also depends on the concentration of the liquid used in the feedstock, it is still possible for about 1 to tens of ppm of halide ions to be mixed into the aqueous solution of quaternary ammonium hydroxide.

[0124] The method for manufacturing photoresist developer may include a preparation step of preparing an aqueous quaternary ammonium halide solution to be used as a raw material in the electrolysis process, prior to the electrolysis process described above.

[0125] The preparation process is not particularly limited; for example, it can be prepared by manufacturing an aqueous solution of a quaternary ammonium halide. Furthermore, the method for manufacturing the aqueous solution of the quaternary ammonium halide is not particularly limited. For example, from the viewpoint of productivity and quality, the process of reacting a trialkylamine with a haloalkane in ultrapure water to obtain the quaternary ammonium halide is preferred.

[0126] The trialkylamine and haloalkane used as raw materials are not particularly limited as long as the quaternary ammonium ion shown in the above formula (1) can be obtained. Specifically, substances in which one or more of the alkyl groups contained in the trialkylamine and the alkyl groups contained in the haloalkane are alkyl groups with 2 to 16 carbon atoms (preferably 2 to 8, more preferably 2 to 4), and the other alkyl groups are alkyl groups with 1 to 16 carbon atoms (preferably 1 to 8, more preferably 1 to 4).

[0127] In addition, if the photoresist developer contains tetramethylammonium ions, the trialkylamine may contain trimethylamine, and the alkyl group contained in the haloalkane may be methyl.

[0128] In addition, the halide ion that serves as the anion of the haloalkane can be the same ion as described in (B) above.

[0129] Impurities contained in quaternary ammonium halides can diffuse and mix into the aqueous solution of quaternary ammonium hydroxide; therefore, high-purity quaternary ammonium halides are preferred. Specifically, the concentration of alcohol in the aqueous solution of quaternary ammonium halide is preferably 0.1 to 10,000 ppm by mass, more preferably 0.1 to 100 ppm by mass. Furthermore, the concentration of amine is preferably 0.1 to 10,000 ppm by mass, more preferably 0.1 to 100 ppm by mass.

[0130] The photoresist developer can develop the exposed photoresist layer. That is, the photoresist development method of the present invention may include a development step of developing the exposed photoresist layer using the photoresist developer of the present invention. As the development step, the same step as the development step in the semiconductor device manufacturing method described later may be used.

[0131] Furthermore, as described later, the photoresist layer comprises a photosensitive resin. That is, the photoresist developer is preferably a developer for developing the exposed photoresist layer containing the photosensitive resin. In the photosensitive resin, the polymer contained in the photosensitive resin may be photosensitive, or it may be photosensitive by containing a photosensitive agent. For example, the polymer contained in the photosensitive resin may undergo chemical or structural changes through exposure, and the photosensitive agent contained in the photosensitive resin may undergo chemical or structural changes through exposure. Additionally, chemical or structural changes in the photosensitive resin may occur due to changes in the photosensitive material (chemically amplified photoresist). Known photosensitive agents can be used as the photosensitive agent.

[0132] Another aspect of the present invention is the application of a photoresist developer for developing a photoresist layer containing a photosensitive resin.

[0133] The following describes a method for manufacturing a semiconductor device according to one aspect of the present invention.

[0134] The fabrication of semiconductor devices using the photoresist developer of this invention can be carried out according to known methods.

[0135] For example, methods for manufacturing semiconductor devices include:

[0136] In the exposure process, light is irradiated onto the photoresist layer on the substrate through a photomask with a specified pattern; and

[0137] In the development process, the photoresist layer exposed in the above exposure process is developed to form a resist pattern corresponding to the pattern of the above photomask. In the above development process, the exposed photoresist layer is developed using the above photoresist developer.

[0138] In addition to the above-mentioned processes, the manufacturing method of semiconductor devices may also include the following processes.

[0139] For example, a process can be described as forming a photoresist layer by applying a coating liquid containing a photosensitive resin to a specified substrate surface and then drying it. The drying temperature in the formation process is not particularly limited, but examples include 50–190°C, preferably 70–160°C. Furthermore, the drying time is not particularly limited, but examples include 30–150 seconds, preferably 60–120 seconds.

[0140] The coating solution may contain, for example, a photosensitive resin and a solvent. There are no particular limitations on the solvent, as long as it can dissolve the photosensitive resin; for example, ester-based solvents such as propylene glycol monomethyl ether acetate or ketone-based solvents can be used.

[0141] There are no particular limitations on the method of applying the coating liquid; well-known methods can be used, such as spin coating.

[0142] The thickness of the photoresist layer is not particularly limited, but is preferably 1 nm to 20 μm.

[0143] Furthermore, the semiconductor device manufacturing method may include, after the developing process, a cleaning process in which the developer containing dissolved resist components is removed using a rinsing solution, and a drying process in which the semiconductor device obtained in the cleaning process is dried. The cleaning time in the cleaning process is not particularly limited; examples include 10 to 120 seconds, preferably 10 to 90 seconds. The temperature of the cleaning process is also not particularly limited; examples include 10 to 40°C. As the rinsing solution, known water such as ion-exchanged water can be used.

[0144] There are no particular limitations on the drying temperature during the drying process; for example, 50~100℃ can be listed. Similarly, there are no particular limitations on the drying time; for example, 30~150 seconds can be listed.

[0145] Furthermore, when using chemically amplified photoresist, in order to promote acid generation, the semiconductor device manufacturing method preferably includes a heating step for heating the photoresist layer. The heating temperature is not particularly limited, but examples include 70 to 110°C. This heating step is performed after the exposure step. The heating time in the heating step is not particularly limited, but examples include 1 to 10 minutes.

[0146] In the exposure process, light is irradiated onto a photoresist layer on a substrate through a photomask with a predetermined pattern. Preferably, the wavelength of the light is appropriate for the photosensitivity of the photoresist. In the case of forming fine resist patterns, short-wavelength light such as an excimer laser is used. Exposure based on electron beams or X-rays can also be performed, depending on the type of photoresist. Examples of light sources include: mercury lamps for gamma rays (436 nm), h-rays (405 nm), and i-rays (365 nm); excimer lasers for KrF (248 nm) and ArF (193 nm); EUV (13.5 nm) light sources; and electron beam light sources. That is, the photoresist developer can be a photoresist developer for developing photoresist layers exposed using one or more light sources selected from the group consisting of mercury lamps, excimer lasers, EUV light sources and electron beam light sources, or it can be a photoresist developer for developing photoresist layers exposed using one or more excimer lasers selected from the group consisting of KrF excimer lasers and ArF excimer lasers.

[0147] Another aspect of the present invention is the application of a photoresist developer for developing an exposed photoresist layer. Exposure can be performed using the aforementioned light source. For example, the application can also be a photoresist developer for developing a photoresist layer exposed using an excimer laser. Furthermore, the application of a photoresist developer for developing a photoresist layer exposed using one or more excimer lasers selected from the group consisting of KrF excimer lasers and ArF excimer lasers is preferred.

[0148] A photoresist layer is a layer containing a photosensitive resin (photoresist). There are no particular limitations on the type of photoresist; it can be either a positive or negative photoresist. A positive photoresist is a photosensitive resin that is soluble in the developer in the exposed areas, while a negative photoresist is a photosensitive resin that is insoluble in the developer in the exposed areas.

[0149] Examples of positive photoresists include methacrylic resins such as poly(meth)acrylate, urethane resins such as polyurethane, phenolic resins such as phenolic varnish resins, styrene resins such as polyhydroxystyrene (PHS) resins, and resins with an aliphatic polycyclic skeleton. Preferably, one or more resins are selected from the group consisting of methacrylic resins and styrene resins. These resins can be used individually or in combination of two or more.

[0150] Examples of negative photoresists include polyvinyl cinnamate and mixtures of resins with unsaturated carbon bonds and azides.

[0151] As mentioned above, polyhydroxystyrene resin can be cited as an example of a styrene resin.

[0152] As a photoresist containing polyhydroxystyrene resin, it is preferable that a portion of the hydroxyl groups of the polyhydroxystyrene resin contained in the photoresist are replaced by protecting groups. By introducing protecting groups, the photoresist becomes insoluble in the photoresist developer in unexposed areas. Alternatively, a chemical reaction occurs in the exposed areas where the protecting groups are removed and replaced by hydroxyl groups, making the photoresist soluble in the photoresist developer. In this case, when the amount of hydroxyl groups of the polyhydroxystyrene resin contained in the photoresist is set to 100 mol, the amount of protecting groups in the polyhydroxystyrene resin is preferably 75 to 300 mol, more preferably 90 to 200 mol.

[0153] There are no particular limitations on the protecting group; examples include acetal, ketal, silyl, silyl ether, and tert-alkyl ester groups. The protecting group can have any substituents and can also have a cyclic structure. Specifically, tert-butoxycarbonyl, isopropoxycarbonyl, and benzyloxycarbonyl groups can be used, among others. Tert-butoxycarbonyl is preferred.

[0154] In a dissolution rate evaluation test of a photoresist layer containing polyhydroxystyrene resin at a temperature of 23°C, the ratio of hydroxyl groups to tert-butoxycarbonyl groups in the polyhydroxystyrene resin was 70:30 (based on mass), and the thickness of the photoresist layer was 200 nm. The dissolution rate of the photoresist layer using the photoresist developer of the present invention was preferably 110% or more, more preferably 130% or more, compared to the dissolution rate of the photoresist layer using a photoresist developer containing tetramethylammonium hydroxide. The above-mentioned range of dissolution rates indicates excellent solubility of the photoresist near the boundaries of photomasks where light-based chemical reactions are difficult to occur. As a result, the pattern shape is easily improved. The specific method for the dissolution rate evaluation test will be described later; the temperature of the dissolution rate evaluation test refers to the temperature of the photoresist developer of the evaluated object.

[0155] There is no particular upper limit to the above dissolution rate; for example, 110-500%, 110-300%, and 130-200% can be listed.

[0156] The aforementioned dissolution rate can be achieved, for example, by changing the alkyl group R in the quaternary ammonium ion shown in formula (1) above. 1 ~R 4 The number of carbon atoms is used to adjust this. For example, if R is used... 1 R 2 R 3 and R 4 In compounds where any three methyl groups are methyl groups and the remaining alkyl group is an alkyl group with 2 to 16 carbon atoms, the dissolution rate tends to be high. If the number of carbon atoms in the alkyl group serving as the lipophilic part is too large, the dissolution rate of the resist layer will decrease due to adsorption inhibition; therefore, the number of carbon atoms in the alkyl group serving as the lipophilic part is 16 or less. Furthermore, the number of carbon atoms in the alkyl group is preferably 8 or less, more preferably 4 or less. Additionally, if R... 1 R 2 R 3 and R 4 If any three of them are methyl groups, a hydrophilic portion is formed relative to the above-mentioned oleophilic portion, thus improving the wettability with the photoresist resin and increasing the dissolution rate, which is therefore preferred.

[0157] As described above, (meth)acrylic resins can be cited as photoresists. The structure of (meth)acrylic resins is not particularly limited, but they preferably have monomer units as shown in formula (D) below. Furthermore, the monomer units shown in formula (D) below can be the same monomer unit or different monomer units.

[0158]

[0159] In formula (D), Rx represents any protecting group, and Ry represents hydrogen or methyl.

[0160] The protecting group shown in Rx is not particularly limited as long as it is a functional group that is removed by exposure. For example, hydrocarbon groups with 3 to 12 carbon atoms (preferably 6 to 9 carbon atoms) can be listed. The hydrocarbon group can be straight-chain, branched, or cyclic. Alicyclic hydrocarbon groups are preferred.

[0161] The content of the monomer unit represented by formula (D) in (meth)acrylic resin is not particularly limited, and can be 50 to 100 parts by weight or 70 to 100 parts by weight.

[0162] Specifically, preferred are 2-alkyl-substituted adamantoxycarbonyl such as tert-butoxycarbonyl, 2-methyladamantoxycarbonyl, 2-alkyl-substituted norbornel such as 2,6-carbonyl lactone norbornel, and 2-pyranoxycarbonyl.

[0163] In the development process, the photoresist layer exposed in the exposure process is developed to form a resist pattern corresponding to the pattern of the photomask. In the semiconductor device manufacturing method of the present invention, the exposed photoresist layer is developed using the aforementioned photoresist developer. That is, a resist pattern is formed on the substrate, forming areas covered by the resist pattern and areas not covered by the resist pattern.

[0164] The preferred method for developing the photoresist layer is, for example, coating the photoresist developer of the present invention onto the photoresist layer exposed during the exposure process.

[0165] The development of the exposed photoresist layer is not particularly limited except for the photoresist developer mentioned above. For example, known methods such as immersion development, spin-dip development, and spray development can be used without specific limitations. Immersion development refers to a development method in which the substrate, such as a silicon wafer with the photoresist layer formed, is immersed in a developer for a certain period of time, then immersed in pure water and dried. Spin-dip development refers to a development method in which developer is dropped onto the photoresist layer, left to stand for a certain period of time, then rinsed with pure water and dried. Spray development refers to a development method in which developer is sprayed onto the photoresist layer, then rinsed with pure water and dried.

[0166] At this point, if the photoresist is a positive photoresist, the exposed areas of the photoresist layer that were exposed during the exposure process are removed. On the other hand, if the photoresist is a negative photoresist, the unexposed areas of the photoresist layer that were not exposed during the exposure process are removed.

[0167] The temperature of the developing process is not particularly limited, but can be listed as 10~40℃, preferably 15~30℃. The time of the developing process is not particularly limited, but can be listed as 10~120 seconds, preferably 10~90 seconds.

[0168] It should be noted that semiconductor substrate is a term used in the semiconductor device manufacturing process.

[0169] A preferred method for manufacturing semiconductor devices includes a processing step that processes areas of a substrate with a resist pattern on its surface that are not covered by the resist pattern. This processing step is performed after the development step. By including this processing step, the method for manufacturing semiconductor devices enables the production of semiconductor devices having a substrate with a pattern. Known methods can be used as processing methods, such as wet etching, dry etching, and plating.

[0170] Example

[0171] The following embodiments are shown to illustrate the present invention in detail, but the present invention is not limited to these embodiments. It should be noted that the evaluation of the implementation in the embodiments and comparative examples was obtained by the following methods.

[0172] <Examples 1-7, Comparative Examples 1-3>

[0173] [Photoresist developer]

[0174] Each quaternary ammonium hydroxide aqueous solution was prepared to a concentration of 0.26 mol / L and used as the photoresist developer. Furthermore, the dissolution rate of the photoresist was evaluated using the method described later.

[0175] • Ethyltrimethylammonium hydroxide (ETMAH, made from raw materials)

[0176] • Propyltrimethylammonium hydroxide (PTMAH, made from raw materials)

[0177] Butyltrimethylammonium hydroxide (BTMAH, made from raw materials)

[0178] Tetramethylammonium hydroxide (TMAH, manufactured by TOKUYAMA CORPORATION)

[0179] Tetraethylammonium hydroxide (TEAH, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0180] [surfactant]

[0181] Surfynol 465 (registered trademark) (manufactured by Nissin Chemical Co., Ltd.)

[0182] Preparation of Quaternary Ammonium Hydroxide Aqueous Solution

[0183] ETMAH, PTMAH, and BTMAH are prepared according to the following steps. A quaternary ammonium halide aqueous solution is prepared from trialkylamine and haloalkanes as raw materials, and then used as a raw material to produce a quaternary ammonium hydroxide aqueous solution by electrolysis. Specifically, in the case of ETMAH, trimethylamine and chloroethane are added in a 1:1 molar ratio to a reaction vessel containing ultrapure water, and the reaction is maintained at 60°C to prepare a 50% (w / w) ethyltrimethylammonium chloride aqueous solution. The solution is then subjected to reduced pressure until the unreacted trimethylamine and chloroethane, and the byproduct ethanol, are each below 100 ppm. Figure 1 The electrolytic cell shown is used to fabricate ETMAH. Figure 1 In the diagram, 1 represents the anode, 2 represents the cathode, 3 represents the power source, 4 represents the anode chamber, 5 represents the raw material chamber, 6 represents the intermediate chamber, 7 represents the cathode chamber, 8 represents the anion exchange membrane, and 9 represents the cation exchange membrane.

[0184] The cathode uses a platinum-plated nickel plate, the anode uses a platinum-plated titanium plate, the cation exchange membrane uses two Nafion N324 membranes (manufactured by Chemours), and the anion exchange membrane uses ASE (manufactured by Astom). Specifically, 0.5 equivalence (N) hydrochloric acid is circulated in the anode chamber, 50% (w / w) ethyltrimethylammonium chloride aqueous solution is circulated in the feed chamber between the anion exchange membrane and the cation exchange membrane on the cathode side, and ultrapure water is circulated in the intermediate chamber between the cathode chamber and the two cation exchange membranes. The current density is gradually increased and eventually maintained at 30 A / dm³. 2 Electrolysis was performed continuously at a current density of 40°C and a temperature of 40°C. During electrolysis, an aqueous solution of ethyltrimethylammonium chloride (ETMAH) was added to maintain the ETMAH concentration in the feed chamber at 40% by mass or higher. Electrolysis was terminated when the ETMAH concentration in the cathode chamber reached 30% by mass, yielding an aqueous ETMAH solution. This ETMAH aqueous solution was diluted with ultrapure water and used in Example 1 at the concentrations listed in Table 1.

[0185] For the preparation of PTMAH and BTMAH, chloropropane and chlorobutane were used as haloalkanes, respectively, at the concentrations listed in Table 1. Otherwise, the preparation was carried out in the same manner as ETMAH, and they were used in Examples 2-7. Additionally, the surfactants listed in Table 1 were added to Examples 6-7 and Comparative Example 3.

[0186] The concentration of amines in the photoresist developers of Examples 1-7 and Comparative Examples 1-3 was all below 100 ppm by mass. Furthermore, the concentration of alcohols in the photoresist developers of Examples 1-7 and Comparative Examples 1-3 was all below 100 ppm by mass. Additionally, the concentrations of calcium, sodium, potassium, chromium, nickel, iron, lead, and aluminum ions in the photoresist developers of Examples 1-7 and Comparative Examples 1 and 3 were all below 0.1 ppb. Furthermore, the photoresist developer of Comparative Example 2 was purified using a cation exchange resin, reducing the concentrations of calcium, sodium, potassium, chromium, nickel, iron, lead, and aluminum ions in the photoresist developer to below 0.1 ppb.

[0187] [Evaluation Method]

[0188] 1) Determination of halide ion concentration

[0189] When the concentration of quaternary ammonium hydroxide in the photoresist developer is below 5% by mass, it can be used directly. When the concentration exceeds 5% by mass, it should first be diluted to 5% by mass with ultrapure water before being passed into an OnGuard Cartridge II H+ type 2.5cc (manufactured by Thermo Fisher Scientific). The liquid is then recovered, and anion analysis of the recovered liquid is performed using an ion chromatograph (Integrion, manufactured by Thermo Fisher Scientific) to determine the halide ion concentration.

[0190] 2) Hydroxide ion concentration

[0191] For 1 mL of the developer prepared in the examples and comparative examples, a neutralization titration was performed using a Hiranuma automatic titration apparatus (COM-1700, manufactured by HIRANUMA) with 0.1 mol / L hydrochloric acid. The hydroxide ion concentration of the photoresist developer was determined based on the volume of 0.1 mol / L hydrochloric acid required for neutralization.

[0192] 3) Evaluation of the dissolution rate of the photoresist layer

[0193] The dissolution rate of the photoresist layer relative to the photoresist developer was evaluated using the QCM method (Quartz Crystal Microbalance Method).

[0194] A photoresist resin (described later) was spin-coated onto a QCM substrate and pre-baked at 90°C for 90 seconds to form a 200 nm thick photoresist layer. This photoresist layer was then immersed in a photoresist developer at 23°C, and the dissolution rate was evaluated. The dissolution rate was determined by the time required for the impedance value, measured by the QCM method, to rise and then fall. If the photoresist layer completely dissolves, the interfacial viscosity decreases; therefore, a shorter impedance drop time indicates a faster dissolution rate.

[0195] The photoresist resin is prepared in liquid form using pre-exposure and post-exposure resin compositions. Specifically, the following resin is prepared: a resin (30% t-Boc-PHS) in which the hydroxyl groups (OH groups) of polyhydroxystyrene are protected with tert-butoxycarbonyl groups (t-Boc groups) and substituted at a mass ratio of OH groups:t-Boc groups = 70:30, using a liquid prepared by dissolving propylene glycol monomethyl ether acetate (PGMEA).

[0196] Dissolution rate was evaluated using 2.4% by mass (0.26 M) TMAH as a baseline, according to the evaluation criteria below. The results are presented as "Dissolution Rate" in Table 1.

[0197] (Evaluation Criteria)

[0198] A: TMAH's dissolution rate is over 130%.

[0199] B: The dissolution rate of TMAH is above 110% and below 130%.

[0200] C: TMAH dissolves at a rate of over 90% and less than 110%.

[0201] D: Dissolution rate less than 90% of TMAH.

[0202] 4) Evaluation of development characteristics

[0203] The evaluation of development characteristics involves creating patterns for different resists A and B and evaluating their shapes.

[0204] [Pattern formation using resist A]

[0205] 100 parts by weight of polyhydroxystyrene (weight average molecular weight 10,000) in which 50 mol% of the hydrogen atoms of the hydroxyl groups are replaced by tert-butoxycarbonyl groups.

[0206] · 5 parts by weight of triphenylsulfonium hexafluoroantimonate

[0207] 0.2 parts by weight of triethanolamine

[0208] Propylene glycol monomethyl ether acetate (PGMEA) 400 parts by weight

[0209] The prepared resist A was spin-coated onto a silicon wafer treated with hexamethyldisilazane using a spin coater. The wafer was then 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 then exposed using a KrF exposure apparatus, with a KrF excimer laser passing through a mask pattern (1:1 lines and gaps with a linewidth of 260 nm). Following this, it was exposed at 110°C for 60 seconds and then baked. Subsequently, it was developed using an aqueous solution of quaternary ammonium hydroxide at the concentrations shown in Table 1 at 23°C for 30 seconds, rinsed with ultrapure water for 30 seconds, and dried to obtain the patterned shape.

[0210] [Pattern formation using resist B]

[0211]

[0212] • 100 parts by weight of a copolymer containing monomer units shown in formula (2-1) and monomer units shown in formula (2-2) in a molar ratio of 50:50 (weight average molecular weight 14000)

[0213] 1.5 parts by weight of triphenylsulfonate trifluoromethanesulfonate

[0214] 0.1 parts by weight of triethanolamine

[0215] The above materials were dissolved in a mixed solvent of 950 parts by mass of propylene glycol monomethyl ether acetate (PGMEA) and 100 parts by mass of γ-butyrolactone to obtain a positive resist solution. Next, the resist solution was spin-coated onto a silicon wafer and dried on a hot plate at 140°C (pre-baking) for 90 seconds to form a 250 nm resist layer. Then, an ArF excimer laser (193 nm) was used to irradiate the wafer through a mask pattern (1:1 lines and gaps with a linewidth of 100 nm). Following this, a post-exposure bake (PEB) treatment was performed at 130°C for 90 seconds. Next, the wafer was developed by 20 seconds of spin-dip development with an aqueous solution of quaternary ammonium hydroxide at the concentrations shown in Table 1, followed by a 60-second water wash and drying.

[0216] [Right-shape evaluation]

[0217] The state of the lines and gaps formed by the above pattern was observed using a scanning electron microscope (JSM-7800F Prime, manufactured by Nippon Electron Ltd.). Ten points along the width of the exposed bottom were observed, and the arithmetic mean of the observed widths was calculated. Then, the dimensional difference between the arithmetic mean of the observed widths and the size of the mask pattern was calculated using the following formula. The results were then evaluated according to the following criteria. The results are presented in Table 1 as "Development Shape".

[0218] (Size difference (%)) = (Mask pattern size (nm) - Arithmetic mean of widths (nm)) / Mask pattern size (nm) × 100

[0219] (Evaluation Criteria)

[0220] A: Size difference less than 3%

[0221] B: Size difference is 3% or more but less than 5%

[0222] C: Size difference is 5% or more but less than 10%

[0223] D: Dimensional difference is 10% or more, or resist residue prevents the bottom from being visible.

[0224] 5) Surface tension

[0225] The surface tension of the developing solutions prepared in the examples and comparative examples was measured at 25°C using a surface tension meter DY-300 (manufactured by Kyowa Interface Chemical Co., Ltd.). The measurements were performed according to JIS 2241, "Test Method Using a Wilhelmi Surface Tensiometer".

[0226] (Example 8)

[0227] Except that the Cl concentration in Example 1 was 210 ppm, the same photoresist developer as in Example 1 was used to evaluate the development characteristics of resist A. The result was that the development shape was evaluated as B, the same as in Example 1, but the proportion of resist residue increased compared to Example 1.

[0228] (Example 9)

[0229] Except that the Cl concentration in Example 2 was set to 85 ppm, the same photoresist developer as in Example 2 was used to evaluate the development characteristics of resist A. The results showed that the development shape was the same as in Example 1 (evaluation A), but compared to Example 2, the proportion of resist residue increased.

[0230] [Table 1]

[0231]

[0232] In the table, "-" indicates that the solution rate and surface tension were not measured.

[0233] As shown in Table 1, ETMAH, PTMAH, and BTMAH exhibited faster dissolution rates and superior development characteristics compared to TMAH. During development, protective groups tend to remain near the mask in the exposed area. In the case of TMAH alone, dissolution residue occurs on the sides of the exposed area, resulting in a narrower bottom width relative to the linewidth of the mask pattern. On the other hand, ETMAH, PTMAH, and BTMAH exhibit less dissolution residue on the sides of the exposed area, with the bottom width approaching the linewidth of the mask pattern, resulting in a more rectangular pattern with sides nearly perpendicular to the bottom. Furthermore, when BTMAH and TMAH are mixed, there is less dissolution residue on the sides compared to the case of TMAH alone, resulting in a more rectangular pattern. It can be seen that further addition of a small amount of surfactant further reduces dissolution residue.

[0234] Industrial availability

[0235] The photoresist developer of the present invention can be used as a photoresist developer with good pattern shape.

[0236] Explanation of reference numerals in the attached figures

[0237] 1: Anode

[0238] 2: Cathode

[0239] 3: Power supply

[0240] 4: Anode Chamber

[0241] 5: Raw Material Room

[0242] 6: Intermediate Room

[0243] 7: Cathode Chamber

[0244] 8: Anion exchange membrane

[0245] 9: Cation exchange membrane

Claims

1. A photoresist developer comprising the following (A), (B), (C), and (D): (A) The quaternary ammonium ion shown in formula (1) below, (B) Halogen ions, (C) hydroxide ions, (D) Water In equation (1), R 1 R 2 R 3 and R 4 Each is an alkyl group having 1 to 16 carbon atoms, wherein, R 1 R 2 R 3 and R 4 In this context, the number of carbon atoms in one or more alkyl groups is 2 to 16, and R 1 R 2 R 3 and R 4 Not all of them are the same alkyl group.

2. The photoresist developer according to claim 1, wherein, The surface tension of the photoresist developer is below 73.0 mN / m at 25°C.

3. The photoresist developer according to claim 1 or 2, wherein, R in equation (1) 1 R 2 and R 3 For methyl, R in formula (1) 4 It is an alkyl group with 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. The photoresist developer according to any one of claims 1 to 4, wherein, When the weight of hydroxide ions in the photoresist developer is set to 1 part by weight, the weight of halide ions is 0.0000001 to 0.01 parts 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, wherein the photoresist developer is used to develop an exposed photoresist layer containing a photosensitive resin.

8. The photoresist developer according to any one of claims 1 to 7, wherein, 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 the content of each metal ion in the photoresist developer is independently less than 1 ppb.

9. The photoresist developer according to any one of claims 1 to 8, used for developing a photoresist layer exposed using 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 the dissolution rate evaluation test of the photoresist layer containing polyhydroxystyrene resin at a temperature of 23°C... The ratio of hydroxyl groups to tert-butoxycarbonyl groups in the polyhydroxystyrene resin is 70:30 on a mass basis. The thickness of the photoresist layer is 200 nm. The dissolution rate of the photoresist layer when using the aforementioned photoresist developer is 110% or more higher than 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, wherein the concentration of the surfactant in the photoresist developer is 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 development method, comprising a development step of developing an exposed photoresist layer using the photoresist developer solution according to any one of claims 1 to 12.

14. A method for manufacturing a semiconductor device, comprising: In the exposure process, light is irradiated onto the photoresist layer on the substrate through a photomask with a specified pattern; and The developing process involves developing the photoresist layer exposed in the exposure process to form a resist pattern corresponding to the pattern of the photomask. In the developing process, the photoresist developing solution according to any one of claims 1 to 12 is used to develop the exposed photoresist layer.

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