Curable composition and agent for forming etching-resistant film

Abstract

This curable composition contains the following component (A) and component (B). Component (A): at least one selected from the group consisting of a silane compound represented by formula (a-1) and a silane compound represented by formula (a-2) Component (B): a metal compound represented by formula (b-1) Silane compound represented by formula (a-1): R1Si(X1)p(ORa)3-p [R1 represents an organic group having an amino group. X1 represents a halogen atom. Ra represents a hydrogen atom or an organic group. p represents an integer of 0 to 3.] Silane compound represented by formula (a-2): R2R3Si(X2)q(ORb)2-q [R2 and R3 each independently represent an organic group, and at least one thereof is an organic group having an amino group. X2 represents a halogen atom. Rb represents a hydrogen atom or an organic group. q represents an integer of 0 to 2.] Metal compound represented by formula (b-1): M(X3)r(ORc)n-r [M represents a specific n-valent metal atom such as Al. X3 represents a halogen atom. Rc represents a hydrogen atom or an organic group. r represents an integer of 0 to n.]

Description

Curable composition and etching resistance film-forming agent

[0001] The present disclosure relates to a curable composition and an etching resistance film-forming agent.

[0002] In recent years, microfabrication of silicon materials has been performed in the manufacturing processes of semiconductor devices and the manufacturing processes of MEMS (Micro Electro Mechanical Systems). For example, Patent Document 1 describes a silicon etching solution containing a quaternary ammonium hydroxide, amines, and a solvent, and a method for etching a silicon substrate using this silicon etching solution.

[0003] As etching methods, in addition to wet etching using an etching solution as described in Patent Document 1, dry etching using an etching gas is known. For example, Patent Document 2 describes a method of dry etching a single crystal silicon wafer using a fluorine-based gas to form a rough surface on the single crystal silicon wafer.

[0004] Japanese Patent Application Laid-Open No. 2023-152834 (US Patent Application Publication No. 2023 / 0357635) Japanese Patent Application Laid-Open No. 2023-177967

[0005] According to Patent Document 2, the fluorine-based gas functions as an etching gas when processing silicon materials. Therefore, it is considered that by forming a film having a predetermined pattern and excellent etching resistance against fluorine-based gas on a silicon material, microfabrication of the silicon material can be performed by dry etching.

[0006] The present disclosure has been made under such circumstances, and an object thereof is to provide a curable composition that can be suitably used as a raw material for an etching resistance film, and an etching resistance film-forming agent.

[0007] The Disclosers have diligently studied etching-resistant films in order to solve the above problems. As a result, they have found that: 1) etching-resistant films containing metal atoms exhibit excellent etching resistance to fluorine-based gases; 2) metal compounds with hydrolysis condensation properties generally have low solubility in solvents, making it difficult to obtain raw material solutions for etching-resistant films containing metal atoms; and 3) by using a metal compound with hydrolysis condensation properties in combination with a silane compound containing an organic group with an amino group, it becomes easier to obtain a solution of the metal compound with hydrolysis condensation properties. Based on these findings, they have completed this disclosure.

[0008] Thus, the present disclosure provides the following curable compositions [1] to [4] and etching-resistant film-forming agent [5]. [1] A curable composition containing the following components (A) and (B). Component (A): At least one selected from the group consisting of a silane compound represented by the following formula (a-1) and a silane compound represented by the following formula (a-2).

[0009]

[0010] [R １ X represents an organic group containing an amino group. １ R represents a halogen atom. ａ [where 'p' represents a hydrogen atom or organic group, and 'p' represents an integer from 0 to 3.]

[0011]

[0012] [R ２ , R ３ Each of these independently represents an organic group, and at least one of them is an organic group having an amino group. ２ R represents a halogen atom. ｂ represents a hydrogen atom or organic group. q represents an integer from 0 to 2. (B) Component: A metal compound represented by the following formula (b-1)

[0013]

[0014] [M represents an n-valent atom selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, In, Sn, Sb, Hf, Ta, and Bi. X ３represents a halogen atom. R ｃ represents a hydrogen atom or an organic group. r represents an integer of 0 to n. [2] The curable composition according to [1], wherein the content ratio of the component (A) to the component (B) [component (A) (mol): component (B) (mol)] is 40:60 to 90:10. [3] The curable composition according to [1] or [2], which has thermosetting properties. [4] The curable composition according to any one of [1] to [3], wherein a selectivity S calculated by the following formula (F1) is 0.75 or less.

[0015]

[0016] (ER １ represents an etching rate when etching a cured product of the curable composition according to any one of [1] to [3] using tetrafluoromethane gas. ER ０ represents an etching rate when etching the mirror surface of a silicon mirror wafer using tetrafluoromethane gas under the same conditions as those for measuring ER １ . [5] An etching resistant film forming agent formed of the curable composition according to any one of [1] to [4].

[0017] According to the present disclosure, there are provided a curable composition suitably used as a raw material for an etching resistant film, and an etching resistant film forming agent.

[0018] In the present disclosure, for preferred numerical ranges (for example, ranges of content, etc.), lower limits and upper limits described stepwise can be combined independently of each other. For example, from the description "preferably 10 to 90, more preferably 30 to 60", "preferred lower limit (10)" and "more preferred upper limit (60)" can be combined to obtain "10 to 60".

[0019] [Silane Compounds] The curable compositions of this disclosure contain, as component (A), at least one selected from the group consisting of a silane compound represented by the following formula (a-1) and a silane compound represented by the following formula (a-2). Hereinafter, the silane compound represented by formula (a-1) and the silane compound represented by formula (a-2) may be referred to as silane compound (a-1) and silane compound (a-2), respectively.

[0020]

[0021]

[0022] Since the curable composition of this disclosure contains component (A), a solution containing component (B) can be efficiently prepared.

[0023] In formula (a-1), R １ R represents an organic group containing an amino group. １ Because it is an organic group having an amino group, component (B) becomes more soluble in the solvent. Since this effect is easily obtained, R １ The amino group is preferably an organic group having two or more amino groups, and more preferably an organic group having a primary amino group and a secondary amino group. Furthermore, it is preferable that these amino groups are in a positional relationship that allows them to form a chelate ring when a metal ion is present. Examples of chelate ring structures include a five-membered ring structure containing a metal ion and two coordination atoms (nitrogen atoms), and a six-membered ring structure containing a metal ion and two coordination atoms (nitrogen atoms).

[0024] R １ The number of carbon atoms is preferably 1 to 20, more preferably 1 to 10. １ Examples include 3-aminopropyl group, N-phenyl-3-aminopropyl group, N-(2-aminoethyl)-3-aminopropyl group, and 3-ureidopropyl group. Among these, R is the most readily available because it is easier to obtain a solution containing a high concentration of component (B). １ The N-(2-aminoethyl)-3-aminopropyl group is preferred.

[0025] In formula (a-1), X １R represents halogen atoms such as fluorine, chlorine, bromine, and iodine. ａ R represents a hydrogen atom or an organic group. ａ When R is an organic group, ａ The number of carbon atoms is preferably 1 to 20, more preferably 1 to 10. ａ OR when is an organic group ａ Examples include alkoxide groups such as methoxide, ethoxide, n-propoxide, isopropoxide, n-butoxide, isobutoxide, sec-butoxide, and tert-butoxide; and carboxylate groups such as acetate, propionate, benzoate, and lactate. p represents an integer from 0 to 3.

[0026] Examples of silane compound (a-1) include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltripropoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, and N-(2-aminoethyl)-3-aminopropyltripropoxysilane. Among these, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, or N-(2-aminoethyl)-3-aminopropyltripropoxysilane are preferred as silane compound (a-1) because a solution containing a high concentration of component (B) is easily obtained. Silane compound (a-1) can be used alone or in combination of two or more.

[0027] In formula (a-2), R ２ , R ３ Each of these independently represents an organic group, and at least one of them is an organic group having an amino group. ２ , R ３ The number of carbon atoms is preferably 1 to 20, more preferably 1 to 10. ２ , R ３ Since at least one of them is an organic group having an amino group, component (B) becomes more soluble in the solvent. Because this effect is easily obtained, R ２, R ３ The organic group having an amino group is preferably an organic group having two or more amino groups, and more preferably an organic group having a primary amino group and a secondary amino group. Furthermore, it is preferable that these amino groups are in a positional relationship that allows them to form a chelate ring when a metal ion is present. Examples of chelate ring structures include a five-membered ring structure containing a metal ion and two coordination atoms (nitrogen atoms), and a six-membered ring structure containing a metal ion and two coordination atoms (nitrogen atoms).

[0028] R is an organic group having an amino group. ２ , R ３ Examples include 3-aminopropyl group, N-phenyl-3-aminopropyl group, N-(2-aminoethyl)-3-aminopropyl group, and 3-ureidopropyl group. Among these, R is an organic group having an amino group because it is easier to obtain a solution containing a high concentration of component (B). ２ , R ３ The N-(2-aminoethyl)-3-aminopropyl group is preferred.

[0029] R is an organic group that does not have an amino group. ２ , R ３ Examples include unsubstituted or substituted (except amino groups) alkyl groups and unsubstituted or substituted (except amino groups) aryl groups.

[0030] R ２ , R ３ The number of carbon atoms in the unsubstituted or substituted alkyl group is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. Note that this number of carbon atoms refers to the number of carbon atoms in the part excluding the substituent (the alkyl group part). Therefore, in the "alkyl group with a substituent having 1 to 20 carbon atoms", R has more than 20 carbon atoms. ２ , R ３ This may include

[0031] R ２ , R ３ The unsubstituted alkyl group may be a linear alkyl group or a branched alkyl group. ２ , R ３Examples of unsubstituted alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, and n-decyl group.

[0032] R ２ , R ３ The number of substituent atoms (excluding hydrogen atoms) of the alkyl group having the substituent is usually 1 to 30, preferably 1 to 20. ２ , R ３ Examples of substituents on alkyl groups having substituents include halogen atoms such as fluorine, chlorine, and bromine atoms; aryl groups such as phenyl groups; alkoxy groups such as methoxy and ethoxy groups; cyano groups; acryloyloxy groups; methacryloyloxy groups; epoxy groups; and the like.

[0033] R ２ , R ３ The number of carbon atoms in the unsubstituted or substituted aryl group is preferably 6 to 20, more preferably 6 to 15, and even more preferably 6 to 10. Note that this number of carbon atoms refers to the number of carbon atoms in the aryl group portion excluding the substituent. Therefore, in "aryl group with substituents having 6 to 20 carbon atoms", R has more than 20 carbon atoms. ２ , R ３ This may include

[0034] R ２ , R ３ Examples of unsubstituted aryl groups include phenyl, 1-naphthyl, 2-naphthyl, tolyl, and xylyl groups.

[0035] R ２ , R ３ The number of substituent atoms (excluding hydrogen atoms) of the aryl group having the substituent is usually 1 to 30, preferably 1 to 20. ２ , R ３ Examples of substituents on an aryl group include halogen atoms such as fluorine, chlorine, and bromine; alkoxy groups such as methoxy and ethoxy groups; cyano groups; acryloyloxy groups; methacryloyloxy groups; epoxy groups; and the like.

[0036] In formula (a-2), X ２ R represents halogen atoms such as fluorine, chlorine, bromine, and iodine. ｂ R represents a hydrogen atom or an organic group. ｂ When R is an organic group, ｂ The number of carbon atoms is preferably 1 to 20, more preferably 1 to 10. ｂ OR when is an organic group ｂ For example, R ａ OR when is an organic group ａ Examples similar to those given as illustrations can be cited. q represents an integer between 0 and 2.

[0037] Examples of silane compounds (a-2) include 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldipropoxysilane, 3-aminopropylmethyldiisopropoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldipropoxysilane, and N-(2-aminoethyl)-3-aminopropylmethyldiisopropoxysilane. Among these, since a solution containing a high concentration of component (B) is easily obtained, the silane compound (a-2) is preferably N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldipropoxysilane, or N-(2-aminoethyl)-3-aminopropylmethyldiisopropoxysilane. The silane compound (a-2) can be used alone or in combination of two or more.

[0038] The curable composition of this disclosure may contain either silane compound (a-1) or silane compound (a-2), or may contain both. When the curable composition of this disclosure contains silane compound (a-1) and silane compound (a-2), the content ratio of silane compound (a-1) to silane compound (a-2) [silane compound (a-1) (mol): silane compound (a-2) (mol)] is preferably 100:0 to 40:60, more preferably 100:0 to 70:30, and even more preferably 100:0 to 90:10.

[0039] [Metal Compounds] The curable composition of this disclosure contains a metal compound represented by the following formula (b-1) as component (B).

[0040]

[0041] The curable composition of this disclosure contains component (B) and is therefore suitably used as a raw material for etching-resistant films that have excellent etching resistance to fluorine-based gases.

[0042] In formula (b-1), M represents an n-valent atom selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, In, Sn, Sb, Hf, Ta, and Bi. n is usually an integer between 2 and 4. Among these, Zn, Al, or Sn are preferred for M because they easily produce etching-resistant films with excellent etching resistance to fluorine-based gases.

[0043] In formula (b-1), X ３ R represents halogen atoms such as fluorine, chlorine, bromine, and iodine. ｃ R represents a hydrogen atom or an organic group. ｃ When R is an organic group, ｃ The number of carbon atoms is preferably 1 to 20, more preferably 1 to 10. ｃ OR when is an organic group ｃ For example, R ａ OR when is an organic group ａ Examples similar to those given as illustrations can be cited. r represents an integer from 0 to n.

[0044] Examples of metal compounds in component (B) include zinc hydroxide, aluminum hydroxide, tin hydroxide, zinc lactate, aluminum lactate, tin lactate, zinc chloride, aluminum chloride, and tin chloride. The metal compounds in component (B) can be used individually or in combination of two or more.

[0045] [Curable Composition] In the curable composition of this disclosure, the content ratio of component (A) to component (B) [(A) (mol):(B) (mol)] is preferably 40:60 to 90:10, and more preferably 45:55 to 85:15. When the content ratio of component (A) to component (B) is within the above range, it is easier to obtain a solution containing high concentrations of component (A) and component (B). Such a solution is suitable as a raw material solution for etching-resistant films.

[0046] The curable compositions of this disclosure may contain a solvent. The solvent is not particularly limited as long as it dissolves components (A) and (B). Examples of solvents include water; alcoholic solvents such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol, and t-butyl alcohol; esteric solvents such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and methyl propionate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; etheric solvents such as tetrahydrofuran and diglyme; and nitrile solvents such as acetonitrile and propionitrile.

[0047] When the curable composition of this disclosure contains a solvent, the amount of solvent is preferably such that the total concentration of component (A) and component (B) is 5 to 50% by mass, and more preferably 10 to 30% by mass. When the curable composition of this disclosure contains a solvent, the concentration of component (A) and component (B) can be increased because the curable composition of this disclosure is a combination of component (A) and component (B).

[0048] The curable compositions of this disclosure may contain components other than component (A), component (B), and the solvent, provided that they do not impair the effects of the disclosure.

[0049] The curable composition of this disclosure can be prepared, for example, by mixing component (A) and component (B) in a solvent.

[0050] The curable composition of this disclosure is preferably thermosetting. By using a thermosetting curable composition, a cured film can be efficiently formed. Such a curable composition is suitably used as a raw material for etching-resistant films. In this disclosure, "thermosetting" means the property of curing by heating alone, even in the absence of a curing catalyst.

[0051] The curable composition of this disclosure preferably has a selectivity ratio S calculated by the following formula (F1) of 0.75 or less. A selectivity ratio S of 0.70 or less is more preferable, and 0.65 or less is even more preferable. There is no particular lower limit for the selectivity ratio S, but it is usually 0 or greater.

[0052]

[0053] In formula (F1), ER １ ER represents the etching rate when etching is performed on the cured product of the curable composition of this disclosure using tetrafluoromethane gas. ０ This involves using tetrafluoromethane gas on the mirror surface of a silicon mirror wafer to perform ER １ This represents the etching rate when etching is performed under the same conditions as the measurement conditions. The etching rate can be calculated from the amount of film thickness reduction after etching and the etching time. Curable compositions with a selectivity ratio S of 0.75 or less are suitably used as raw materials for etching-resistant films that have excellent etching resistance to fluorine-based gases.

[0054] As described above, the curable composition of this disclosure can contain components (A) and (B) in high concentrations, and is therefore useful as a raw material for etching-resistant films, i.e., as an etching-resistant film-forming agent.

[0055] When forming an etching-resistant film using the curable composition of this disclosure, the curable composition is typically applied, the resulting coating is dried, and then the dried coating is cured.

[0056] When applying the curable composition, the spin-coating method is preferably used. The conditions for drying the coating film of the curable composition are, for example, a drying temperature of typically 60 to 150°C, preferably 70 to 120°C, and a drying time of typically 10 seconds to 3 hours, preferably 40 seconds to 2 hours. The conditions for curing the coating film after drying are, for example, a curing temperature of typically 200 to 350°C, preferably 230 to 300°C, and a curing time of typically 30 to 600 seconds, preferably 60 to 400 seconds.

[0057] The thickness of the etching-resistant film is, for example, 10 to 1000 nm, preferably 50 to 500 nm.

[0058] The method for creating patterns on etching-resistant films is not particularly limited. For example, the pattern of the upper layer can be transferred to the etching-resistant film using a multilayer resist method.

[0059] The etching-resistant film formed using the curable composition of this disclosure is suitably used as an etching-resistant film when performing microfabrication of silicon materials by dry etching using a fluorine-based gas.

[0060] Examples of fluorinated gases include tetrafluoromethane (CF ４ ), octafluorocyclobutane (C ４ F ８ ), trifluoromethane (CHF ３ ), difluoromethane (CH ２ F ２ ), Nitrogen Trifluoride (NF ３ ), xenon difluoride (XeF ２ ), xenon hexafluoride (XeF ６ ), sulfahexafluolide (SF ６ Examples include the following. Fluorine-based gases can be used individually or in combination of two or more. In dry etching treatment, inert gases such as He, Ar, Kr, and Xe may be used in combination with fluorine-based gases.

[0061] The present disclosure will be described in more detail below with reference to examples. However, the present disclosure is not limited in any way to the following examples.

[0062] [Example 1] N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (30 mmol, 6.7 g) and zinc hydroxide (10 mmol, 1.0 g) were weighed into a flask, and water was further added in an amount such that the monomer concentration was 15% by mass. Thereafter, the contents of the flask were stirred for 1 hour to obtain a curable composition.

[0063] [Examples 2 to 6, Comparative Example 1] Curable compositions were obtained in the same manner as in Example 1, except that the type and amount of the monomers were changed to those described in Table 1.

[0064] [Comparative Example 2] Methyltrimethoxysilane (30 mmol, 4.1 g) and zinc hydroxide (10 mmol, 1.0 g) were weighed into a flask, and water was further added in an amount such that the monomer concentration was 15% by mass. Thereafter, the contents of the flask were stirred for 1 hour. However, the monomer remained undissolved, and a solution suitable for spin coating was not obtained.

[0065] [Evaluation of Dry Etching Resistance] Each of the curable compositions obtained in Examples 1 to 6 and Comparative Example 1 was spin-coated onto the mirror surface of a 4 cm long × 4 cm square silicon mirror wafer. Thereafter, the obtained coating film was dried at 80°C for 1 minute, and then heated and cured at 280°C for 6 minutes to form a cured film on the silicon mirror wafer.

[0066] Dry etching was performed on the cured film formed on the silicon mirror wafer using a reactive ion etching apparatus (RIE-10NRT, manufactured by Samco Inc.), and the etching rate (nm / min) was calculated from the amount of film thickness reduction and the etching treatment time. The etching conditions are as follows.

[0067] Process gas: tetrafluoromethane (CF ４ 4) Gas flow rate: 40 sccm Output: 250 W Process pressure: 20 Pa Treatment time: 10 to 40 s

[0068] Furthermore, as Reference Example 1, dry etching was performed on the mirror surface of a silicon mirror wafer under the same conditions as above, and the etching rate was 185 nm / min. The selectivity ratio S was calculated based on the etching rate of each cured film. The results are shown in Table 1.

[0069]

[0070] The following can be seen from Table 1. The curable compositions obtained in Examples 1 to 6 contain silane compounds having amino groups. Therefore, even if these curable compositions contain metal compounds, they are homogeneous solutions and can form coating films by spin coating. Furthermore, by using these curable compositions, it is possible to form cured films with low etching rates and excellent etching resistance. On the other hand, the curable composition obtained in Comparative Example 1 does not contain metal compounds. Therefore, the cured film of this curable composition has a high etching rate and poor etching resistance. Also, the curable composition obtained in Comparative Example 2 does not contain silane compounds having amino groups. Therefore, monomers remain undissolved and it did not become a solution suitable for spin coating.

[0071] This application is based on Japanese Patent Application No. 2025-050058, filed on 25 March 2025. The entire specification, claims, and drawings of Japanese Patent Application No. 2025-050058 are incorporated herein by reference.

Claims

1. A curable composition comprising the following component (A) and component (B). Component (A): at least one selected from the group consisting of a silane compound represented by the following formula (a-1) and a silane compound represented by the following formula (a-2) [R １ represents an organic group having an amino group. X １ represents a halogen atom. R ａ represents a hydrogen atom or an organic group. p represents an integer of 0 to 3. ] [R ２ , R ３ each independently represent an organic group, and at least one of them is an organic group having an amino group. X ２ represents a halogen atom. R ｂ represents a hydrogen atom or an organic group. q represents an integer of 0 to 2. ] (B) Component: a metal compound represented by the following formula (b-1) [M represents an n-valent atom selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, In, Sn, Sb, Hf, Ta and Bi. X ３ represents a halogen atom. R ｃ represents a hydrogen atom or an organic group. r represents an integer of 0 to n. ] 2. The curable composition according to claim 1, wherein the content ratio of component (A) to component (B) [component (A) (mol): component (B) (mol)] is 40:60 to 90:

10.

3. The curable composition according to claim 1, wherein it is thermosetting.

4. The curable composition according to claim 1, wherein the selectivity ratio S calculated by the following formula (F1) is 0.75 or less. (ER １ This represents the etching rate when etching is performed on the cured product of the curable composition described in claim 1 using tetrafluoromethane gas. ０ This involves using tetrafluoromethane gas on the mirror surface of a silicon mirror wafer to perform ER １ This represents the etching rate when etching is performed under the same conditions as the measurement conditions.

5. An etching-resistant film-forming agent comprising the curable composition described in claim 1.

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