Composition for forming protective film, protective film, method for manufacturing substrate, and method for manufacturing semiconductor device

Abstract

A composition for forming a protective film for a wet etching solution for semiconductors, comprising: component (A): a film-forming component; component (B): a compound selected from the group consisting of a condensed tannin (b1) obtained by polymerizing a compound having a flavanol skeleton, a hydrolyzable tannin (b2) obtained by ester-bonding a sugar and an aromatic compound of gallic acid or ellagic acid, and a flavonoid (b3) derived from a compound having a flavanone skeleton structure; and component (C): a solvent.

Description

Technical Field

[0001] This invention relates to a protective film forming composition for forming a protective film, particularly a protective film with excellent resistance to wet etchants for semiconductors, in the photolithography process of semiconductor manufacturing. Furthermore, it relates to a method for manufacturing a substrate with a resist pattern using the above-described protective film forming composition, and a method for manufacturing a semiconductor device. Background Technology

[0002] In semiconductor manufacturing, photolithography is a well-known process that forms a resist pattern of desired shape by placing a resist underlayer film between a substrate and a resist film formed thereon. The substrate is then processed after the resist pattern is formed. Dry etching is primarily used for this process, but wet etching is sometimes used depending on the type of substrate. Patent Document 1 discloses a resist underlayer film material resistant to alkaline hydrogen peroxide water.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-173520 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] When a protective film for a semiconductor substrate is formed using a protective film forming composition, and the substrate is processed by wet etching using the protective film as an etching mask, the protective film is required to have good masking function for the wet etching solution used for semiconductors (i.e., the masked portion can protect the substrate). Furthermore, in the semiconductor device manufacturing process, if a large amount of sublimation from the protective film is generated, problems such as contamination of the top plate of the furnace used during firing and the piping may occur.

[0008] The present invention was made in view of the above circumstances, and its object is to provide a protective film forming composition that can form a protective film that suppresses the amount of sublimation while exhibiting excellent resistance to wet etching solutions for semiconductors. Furthermore, the present invention aims to provide a method for manufacturing a substrate with a protective film using the above-described protective film forming composition, a method for manufacturing a substrate with a resist pattern, and a method for manufacturing a semiconductor device.

[0009] Methods for solving problems

[0010] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that the above-mentioned problems could be solved by using a protective film forming composition containing a specific compound, thereby completing the present invention.

[0011] That is, the present invention includes the following solutions.

[0012] [1] A composition for forming a protective film for a wet etching solution for semiconductors, comprising: Component (A): Membrane-forming component; Component (B): A selection of condensed tannins (b1) formed by the polymerization of compounds with a flavanol skeleton, hydrolyzed tannins (b2) formed by the ester bonding of aromatic compounds of gallic acid or ellagic acid with sugars, and compounds derived from flavonoids (b3) having a flavanone skeleton; and Component (C): Solvent.

[0013] [2] In the protective film forming composition according to [1], the above-mentioned component (B) is one or more compounds selected from the above-mentioned condensed tannin and the above-mentioned hydrolyzed tannin.

[0014] [3] In the protective film forming composition according to [1] or [2], the above-mentioned component (B) is the above-mentioned hydrolyzable tannin.

[0015] [4] According to the protective film forming composition of [3], the hydrolyzable tannin is tannic acid as shown in the following formula (I).

[0016]

[0017] (In formula (I) above, G independently represents a hydrogen atom or a monovalent group as shown in formula (II) below.)

[0018] (In equation (II) above, n represents an integer from 0 to 3. The number of benzene rings in equation (I) above is 4 or more and 17 or less. * indicates a bonding bond.)

[0019] [5] The protective film forming composition according to any one of [1] to [4] further comprises component (D): curing catalyst.

[0020] [6] In any one of [1] to [5], the content of the above-mentioned component (B) is 0.1 to 50% by mass relative to the mass of the solid component (A).

[0021] [7] A protective film for a wet etching solution for semiconductors, which is a sintered product of a coating film formed by any one of the protective film forming compositions [1] to [6].

[0022] [8] A method for manufacturing a substrate with a protective film for manufacturing semiconductors, comprising the following steps: applying the protective film forming composition as described in any one of [1] to [6] onto a semiconductor substrate and firing it to form a protective film.

[0023] [9] A method for manufacturing a substrate with a resist pattern for manufacturing semiconductors, comprising the following steps: The process of forming a protective film as a resist underlayer by coating the protective film forming composition described in any one of [1] to [6] onto a semiconductor substrate and firing it; and A photoresist film is formed directly on the aforementioned protective film or through other layers, followed by exposure and development to form a photoresist pattern.

[0024]

[10] A method for manufacturing a semiconductor device includes the following steps: forming a protective film on a semiconductor substrate on which an inorganic film can be formed using a protective film forming composition as described in any one of [1] to [6]; forming a resist pattern on the protective film; dry etching the protective film using the resist pattern as a mask to expose the inorganic film or the surface of the semiconductor substrate; and wet etching and washing the inorganic film or the semiconductor substrate using a semiconductor wet etching solution using the dry-etched protective film as a mask.

[0025] The effects of the invention

[0026] According to the present invention, a protective film forming composition can be provided, which is capable of forming a protective film that suppresses the amount of sublimation while exhibiting excellent resistance to wet etching solutions for semiconductors. Furthermore, according to the present invention, a method for manufacturing a substrate with a protective film using the above-described protective film forming composition, a method for manufacturing a substrate with a resist pattern, and a method for manufacturing a semiconductor device can be provided. Attached Figure Description

[0027] Figure 1A A cross-sectional view of a portion of the semiconductor substrate used in the durability test is shown for illustrative purposes.

[0028] Figure 1B A cross-sectional view of a portion of a semiconductor substrate to illustrate the formation of a protective film is shown.

[0029] Figure 1C A cross-sectional view of a portion of a semiconductor substrate after dry etching is shown schematically.

[0030] Figure 1D A cross-sectional view of a portion of a semiconductor substrate after wet etching is shown schematically. Detailed Implementation

[0031] (Composition for forming a protective film)

[0032] The protective film forming composition of the present invention is a composition for forming a protective film.

[0033] The protective film is suitable for protecting the inorganic film on the surface of a semiconductor substrate from the effects of wet etching.

[0034] The composition for forming a protective film comprises component (A), component (B) and component (C).

[0035] Component (A) is a film-forming component.

[0036] Component (B) is a compound selected from condensed tannins (b1) formed by polymerization of compounds with a flavanol skeleton, hydrolyzed tannins (b2) formed by ester bonding of aromatic compounds of gallic acid or ellagic acid with sugar, and flavonoids (b3) derived from compounds with a flavanone skeleton structure.

[0037] Component (C) is a solvent.

[0038] The inventors conducted extensive research in order to form a protective film with excellent resistance to wet etching solutions for semiconductors. They further discovered that by including an additive (e.g., gallic acid) having an aromatic ring and aromatic hydroxyl groups in the composition for forming the protective film, a protective film with excellent resistance to wet etching solutions for semiconductors can be formed.

[0039] However, the inventors recognized that if the above-mentioned additives are included in the composition for forming a protective film, the amount of sublimation generated by the protective film increases.

[0040] Therefore, further research was conducted, and it was found that by making the composition for forming the protective film not simply contain additives having aromatic rings and aromatic hydroxyl groups, but contains a specific component (B), it is possible to form a protective film that inhibits the amount of sublimation while exhibiting excellent resistance to wet etching solutions for semiconductors, thus completing the present invention.

[0041] <Ingredients (A)>

[0042] Component (A) is a film-forming component. In this specification, the term "film-forming component" refers to any component in the composition for forming a protective film, excluding components (B) and (C).

[0043] The membrane-forming components include, for example, organic compounds. These organic compounds can be low-molecular-weight compounds or high-molecular-weight compounds (polymers).

[0044] Examples of such organic compounds include the following compounds.

[0045] The compounds in the protective film forming compositions described in International Publication No. 2017 / 191767 that have groups represented by formula (1) on their side chains or at their ends and have a weight-average molecular weight of 800 or more. The compounds of formula (1a) or (1b) in the protective film forming compositions described in International Publication No. 2018 / 052130, compounds having a molecular weight of 300 or more and less than 800, or compounds having a weight-average molecular weight of 300 or more and less than 800, are included in the composition. The resins in the protective film forming compositions described in International Publication No. 2018 / 203464 (e.g., polyester, polyether, polyetheretherketone, phenolic varnish resin, maleimide resin, acrylic resin and methacrylic resin). The protective film forming composition described in International Publication No. 2019 / 124474 contains a compound or polymer thereof comprising at least one group of two adjacent hydroxyl groups within its molecule. The protective film forming compositions described in International Publication No. 2019 / 124475 contain compounds or polymers thereof with an intramolecular acetal structure of at least one acetal. The ring-opening polymer (C) obtained by reacting a diepoxide compound (A) with a proton-producing compound (B) with two or more functionalities in the protective film forming composition described in International Publication No. 2020 / 090950 The protective film forming compositions described in International Publication No. 2020 / 153278 contain compounds or polymers comprising at least one acetal structure and one amide structure, respectively. The contents of these public announcements have the same legal effect as those explicitly stated and are incorporated into this specification.

[0046] There are no particular limitations on the polymer, but it is preferred to include a polymer having at least one of the partial structures shown in formula (1), formula (2), and formula (3) below (hereinafter, sometimes referred to as "polymer (A)").

[0047] Polymer (A) more preferably has the partial structure shown in formula (1), the partial structure shown in formula (2) and the partial structure shown in formula (3).

[0048]

[0049] In formula (1), X1 represents a divalent group as shown in formula (1-1), formula (1-2), or formula (1-3) below. Z1 and Z2 each independently represent a directly bonded divalent group or a divalent group as shown in formula (1-4) below. A1, A2, A3, A4, A5, and A6 each independently represent a hydrogen atom, a methyl group, or an ethyl group. * indicates a bonded bond.

[0050] In formula (2), Q1 represents a divalent organic group having an aromatic hydrocarbon ring or an aliphatic hydrocarbon ring. A 11 A 12 A 13 A 14 A 15 and A 16 Each can independently represent a hydrogen atom, a methyl group, or an ethyl group. n1 and n2 can independently represent 0 or 1. * indicates a bonding bond.

[0051] In equation (3), R 11 This represents an organogroup with 1 to 30 carbon atoms. m1 and m2 each independently represent 0 or 1. * indicates a bonding bond.

[0052] (In formulas (1-1) to (1-3), R1 to R5 independently represent a hydrogen atom, an alkyl group with 1 to 10 carbon atoms that can be interrupted by an oxygen or sulfur atom, an alkenyl group with 2 to 10 carbon atoms that can be interrupted by an oxygen or sulfur atom, an alkynyl group with 2 to 10 carbon atoms that can be interrupted by an oxygen or sulfur atom, a benzyl group, or a phenyl group, wherein the phenyl group can be substituted by at least one monovalent group selected from alkyl groups with 1 to 6 carbon atoms, a halogen atom, an alkoxy group with 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group with 1 to 6 carbon atoms. R1 and R2 can combine with each other to form a ring with 3 to 6 carbon atoms. R3 and R4 can combine with each other to form a ring with 3 to 6 carbon atoms. * indicates a bonding bond. *1 indicates a bonding bond bonded to a carbon atom. *2 indicates a bonding bond bonded to a nitrogen atom.)

[0053] (In equation (1-4), m1 is an integer from 1 to 4, and m2 is 0 or 1. *3 represents a bonding bond with a nitrogen atom. *4 represents a bonding bond with a carbon atom.)

[0054] Examples of alkyl groups with 1 to 10 carbon atoms that can be interrupted by oxygen or sulfur atoms in R1 to R5 of formulas (1-1) to (1-3) include, for example, alkyl groups with 1 to 10 carbon atoms, alkoxy groups with 1 to 10 carbon atoms, alkoxyalkyl groups with 2 to 10 carbon atoms, alkoxyalkoxyalkyl groups with 3 to 10 carbon atoms, alkylthio groups with 1 to 10 carbon atoms, alkylthioalkyl groups with 2 to 10 carbon atoms, etc.

[0055] Furthermore, alkyl groups with 1 to 10 carbon atoms that can be interrupted by oxygen or sulfur atoms may contain more than 2 oxygen or sulfur atoms.

[0056] <<X1>>

[0057] As X1 in formula (1), from the viewpoint of obtaining the effects of the present invention, it is preferably represented by formula (1-3).

[0058] As shown in (1A) of equation (1), examples of structures can be given, such as those illustrated below.

[0059]

[0060] (In equation (1A), Z1, Z2, and X1 are the same as Z1, Z2, and X1 in equation (1). * indicates a bonding bond.)

[0061] In the above structure, * represents a bonding bond.

[0062] <<Q1>>

[0063] As Q1 in formula (2), from the viewpoint of obtaining the effects of the present invention, it is preferably represented by any one of the following formulas (2-1) to (2-4).

[0064]

[0065] (In equations (2-1) to (2-4), R) 21 ~R 26 Each of these groups independently represents a halogen atom, hydroxyl group, alkyl group with 1 to 6 carbon atoms, alkenyl group with 2 to 6 carbon atoms, alkynyl group with 2 to 6 carbon atoms, alkoxy group with 1 to 6 carbon atoms, alkenyloxy group with 2 to 6 carbon atoms, alkynyloxy group with 2 to 6 carbon atoms, acyl group with 2 to 6 carbon atoms, aryloxy group with 6 to 12 carbon atoms, arylcarbonyl group with 7 to 13 carbon atoms, or aralkyl group with 7 to 13 carbon atoms. * indicates a bonding bond.

[0066] In equation (2-1), n3 represents 0 or 1. When n3 is 0, n11 represents an integer from 0 to 4. When n3 is 1, n11 represents an integer from 0 to 6. In R 21 When there are two or more R's 21 They can be the same or different.

[0067] In formula (2-2), Z1 represents a single bond, an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group with 1 to 6 carbon atoms. n12 and n13 each independently represent integers from 0 to 4. In R... 22 When there are two or more R's 22 They can be the same or different. In R... 23 When there are two or more R's 23 They can be the same or different.

[0068] In formula (2-3), Y1 and Y2 each independently represent a single bond or an alkylene group with 1 to 6 carbon atoms. n14 represents an integer from 0 to 4. In R... 24 When there are two or more R's 24 They can be the same or different.

[0069] In formula (2-4), Z2 represents a single bond, an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylene group with 1 to 6 carbon atoms. n15 and n16 each independently represent integers from 0 to 4. In R... 25 When there are two or more R's 25 They can be the same or different. In R... 26 When there are two or more R's 26 They can be the same or different.

[0070] In this specification, examples of halogen atoms include fluorine, chlorine, bromine, and iodine.

[0071] In this specification, alkyl groups are not limited to straight-chain forms; they can be branched or cyclic. Examples of straight-chain or branched alkyl groups include methyl, ethyl, isopropyl, tert-butyl, and n-hexyl. Examples of cyclic alkyl groups (cycloalkyl groups) include cyclobutyl, cyclopentyl, and cyclohexyl.

[0072] In this specification, examples of alkoxy groups include, for example, methoxy, ethoxy, n-pentyloxy, isopropoxy, etc.

[0073] In this specification, examples of alkylthio groups include, for example, methylthio, ethylthio, n-pentylthio, isopropylthio.

[0074] In this specification, examples of alkenyl groups include vinyl, 1-propenyl, 2-propenyl, 1-methyl-1-vinyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, etc.

[0075] In this specification, as an alkynyl group, examples of alkenyl groups mentioned above in the term "alkenyl" are groups in which the double bond is replaced by a triple bond.

[0076] In this specification, examples of alkenyloxy groups include, for example, vinyloxy, 1-propenyloxy, 2-n-propenyloxy (allyloxy), 1-n-butenyloxy, isopentenyloxy, etc.

[0077] In this specification, examples of alkynyloxy groups include, for example, 2-propynyloxy, 1-methyl-2-propynyloxy, 2-methyl-2-propynyloxy, 2-butynyloxy, 3-butynyloxy, etc.

[0078] In this specification, examples of acyl groups include, for example, acetyl and propionyl groups.

[0079] In this specification, examples of aryloxy groups include phenoxy and naphthoxy groups.

[0080] In this specification, examples of aryl carbonyl groups include, for example, phenyl carbonyl groups.

[0081] In this specification, examples of aryl alkyl groups include, for example, benzyl and phenethyl.

[0082] In this specification, examples of alkylenes include, for example, methylene, ethylene, 1,3-propylene, 2,2-propylene, 1-methylethylene, 1,4-butylene, 1-ethylethylene, 1-methylpropylene, 2-methylpropylene, 1,5-pentylene, 1-methylbutylene, 2-methylbutylene, 1,1-dimethylpropylene, 1,2-dimethylpropylene, 1-ethylpropylene, 2-ethylpropylene, 1,6-hexylene, 1,4-cyclohexylene, 1,8-octylene, 2-ethyloctylene, 1,9-nonylene, and 1,10-decylene.

[0083] As shown in (2A) of equation (2), examples of structures can be given, for example, the following examples.

[0084]

[0085] (In equation (2A), Q1, n1, and n2 are the same as Q1, n1, and n2 in equation (2). * indicates a bonding bond.)

[0086] In the above structure, * represents a bonding bond.

[0087] R in equation (3) 11Organic groups with 1 to 30 carbon atoms may or may not have aromatic rings. Examples of aromatic rings include aromatic hydrocarbon rings and aromatic heterocycles.

[0088] R in equation (3) 11 Organic groups with 1 to 30 carbon atoms may or may not have aliphatic rings.

[0089] R in equation (3) 11 Organic groups with 1 to 30 carbon atoms may or may not have unsaturated bonds.

[0090] As R in equation (3) 11 Organic groups having 1 to 30 carbon atoms can be exemplified by, for example, alkylene groups having 1 to 10 carbon atoms that can be interrupted by oxygen or sulfur atoms. Alkylene groups having 1 to 10 carbon atoms that can be interrupted by oxygen or sulfur atoms may contain two or more oxygen or sulfur atoms.

[0091] As part of the structure shown in equation (3), the following structures can be cited as examples.

[0092]

[0093] (In the formula, * represents a bonding bond.)

[0094] From the viewpoint of achieving the effects of the present invention, polymer (A) preferably has at least one of the repeating units shown in formula (A) and the repeating units shown in formula (B).

[0095]

[0096] (In equation (A), X1, Z1, Z2, A1, A2, A3, A4, A5 and A6 are the same as X1, Z1, Z2, A1, A2, A3, A4, A5 and A6 in equation (1). R 11 m1 and m2 are respectively related to R in equation (3) 11 m1 and m2 are the same.

[0097] In equation (B), Q1 and A 11 A 12 A 13 A 14 A 15 A 16 n1 and n2 are respectively related to Q1 and A in equation (2). 11 A 12 A 13 A 14 A 15 A 16 n1 and n2 are the same. R11 m1 and m2 are respectively related to R in equation (3) 11 (m1 and m2 are the same.)

[0098] The molar ratio (M1:M2) of the partial structure (M1) shown in formula (1) and the partial structure (M2) shown in formula (2) in polymer (A) is not particularly limited, but is preferably 95:5 to 10:90, more preferably 95:5 to 20:80, and particularly preferably 95:5 to 40:60.

[0099] The molar ratio of the total of the partial structures (M1) shown in formula (1) and the partial structures (M2) shown in formula (2) in polymer (A) to the partial structure shown in formula (3) [(M1+M2):M3] is not particularly limited, but is preferably 80:20 to 20:80, more preferably 70:30 to 30:70, and particularly preferably 60:40 to 40:60.

[0100] The molar ratio (MA:MB) of the repeating unit (MA) shown in formula (A) to the repeating unit (MB) shown in formula (B) in polymer (A) is not particularly limited, but is preferably 95:5 to 10:90, more preferably 95:5 to 20:80, and particularly preferably 95:5 to 40:60.

[0101] The molar percentage of the total repeating unit (MA) shown in Formula (A) and the repeating unit (MB) shown in Formula (B) relative to all repeating units of polymer (A) is not particularly limited, but is preferably 70 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more. As an upper limit, there is no particular limitation, but is preferably 100 mol% or less.

[0102] Examples of polymers (A) include the following polymers (1a) to (1o).

[0103]

[0104] <<Methods for Manufacturing Polymers>>

[0105] As an example of the manufacturing method of polymer (A), there are no particular limitations. For example, a method of reacting at least one of the diepoxide compound shown in formula (A1) and the diepoxide compound shown in formula (A2) with the dicarboxylic acid, monocarboxylic acid or diol shown in formula (A3).

[0106] For example, at least one of the diepoxide compounds shown in formula (A1) and formula (A2) is dissolved in an organic solvent in an appropriate molar ratio with a dicarboxylic acid, monocarboxylic acid, or diol shown in formula (A3). Then, polymerization is carried out in the presence of a catalyst that activates the epoxy groups to obtain a polymer.

[0107] In addition, when manufacturing polymer (A), diepoxide compounds other than those shown in formula (A1) and formula (A2) may be used. Furthermore, when manufacturing polymer, dicarboxylic acids, monocarboxylic acids, or diols other than those shown in formula (A3) may be used.

[0108] Catalysts that activate epoxy groups, such as tetrabutyl bromide, are examples of such catalysts. ethyltriphenylbromide That kind of season Salts, such as quaternary ammonium salts like benzyltriethylammonium chloride. The amount of catalyst used can be selected from 0.1% to 10% by mass relative to the total mass of the polymer feedstock used in the reaction. The optimal conditions for the polymerization reaction can be selected from, for example, a range of 80–160°C and 2–50 hours.

[0109]

[0110] (In equation (A1), X1, Z1, Z2, A1, A2, A3, A4, A5 and A6 are the same as X1, Z1, Z2, A1, A2, A3, A4, A5 and A6 in equation (1).)

[0111] (In equation (A2), Q1, A 11 A 12 A 13 A 14 A 15 A 16 n1 and n2 are respectively related to Q1 and A in equation (2). 11 A 12 A 13 A 14 A 15 A 16 (n1 and n2 are the same.)

[0112] (In equation (A3), R) 11 m1 and m2 are respectively related to R in equation (3) 11 (m1 and m2 are the same.)

[0113] Examples of diepoxide compounds represented by formula (A1) include the following diepoxide compounds.

[0114]

[0115] Examples of diepoxide compounds represented by formula (A2) include the following diepoxide compounds.

[0116]

[0117] Examples of dicarboxylic acids, monocarboxylic acids, or diols represented by formula (A3) include the following compounds.

[0118]

[0119] In addition to the polymer (A) mentioned above, acrylic resins, epoxy resins, phenolic varnish resins, etc., can also be used as polymers.

[0120] There are no particular limitations on the weight-average molecular weight Mw of the polymer (e.g., polymer (A)), but it is preferably 1,000 to 50,000, more preferably 1,500 to 30,000, and particularly preferably 2,000 to 10,000.

[0121] In this invention, the weight-average molecular weight Mw is the polystyrene conversion value obtained by gel permeation chromatography (GPC).

[0122] The content of the polymer (e.g., polymer (A)) in the composition for forming a protective film is not particularly limited, but is preferably 50% to 100% by mass, more preferably 75% to 100% by mass, and particularly preferably 90% to 100% by mass, relative to the film-forming component.

[0123] <Ingredient (B)>

[0124] Component (B) is a compound selected from condensed tannins (b1) formed by polymerization of compounds with a flavanol skeleton, hydrolyzed tannins (b2) formed by ester bonding of aromatic compounds of gallic acid or ellagic acid with sugar, and flavonoids (b3) derived from compounds with a flavanone skeleton structure.

[0125] (b1)

[0126] (b1) is a condensed tannin formed by the polymerization of compounds with a flavanol skeleton.

[0127] In this specification, "tannin" refers to a water-soluble compound derived from plants that reacts strongly with proteins, alkaloids, and metal ions to form insoluble salts. Tannins are aromatic compounds with multiple phenolic hydroxyl groups, widely found in the plant kingdom.

[0128] The tannins involved in this embodiment include condensed tannins and hydrolyzable tannins.

[0129] The condensed tannins involved in this embodiment are compounds polymerized from compounds having a flavanol skeleton as shown in the following formula (p).

[0130] (b2)

[0131] (b2) is a hydrolyzable tannin formed by the ester bonding of aromatic compounds of gallic acid or ellagic acid with sugar.

[0132] The hydrolyzable tannins involved in this embodiment are compounds formed by ester bonding of an aromatic compound of gallic acid or ellagic acid as shown in formula (q) with a sugar such as glucose as shown in formula (r).

[0133]

[0134] As a preferred embodiment of hydrolyzable tannin, examples include, for instance, tannic acid represented by the following formula (I).

[0135]

[0136] (In formula (I) above, G independently represents a hydrogen atom or a monovalent group as shown in formula (II) below.)

[0137] (In equation (II) above, n represents an integer from 0 to 3. The number of benzene rings in equation (I) above is 4 or more and 17 or less. * indicates a bonding bond.)

[0138] From the viewpoint of achieving the effects of the present invention, in formula (II), n is preferably 0 to 2, and more preferably 1 to 2.

[0139] An example of the structure of tannic acid shown in formula (I) above is shown in formula (III) below.

[0140]

[0141] Formula (III) above refers to a compound in which all G in Formula (I) are monovalent groups as shown in Formula (II), and all n in Formula (II) are 1.

[0142] (b3)

[0143] (b3) refers to flavonoids derived from compounds with a flavanone skeleton structure.

[0144] The flavonoids involved in this embodiment refer to compounds that have been biosynthesized by various modifications of flavanones, which are a type of flavonoid.

[0145] Examples of flavonoids involved in this embodiment include compounds derived from compounds having a flavanone skeleton structure as shown in the following formula (s).

[0146]

[0147] As a preferred embodiment of flavonoids, examples include flavonoids represented by the following formula (s1) or (s2).

[0148]

[0149] From the viewpoint of achieving the effects of the present invention, the preferred component (B) is (b2), and more preferably is tannic acid as shown in formula (I).

[0150] From the viewpoint of achieving the effects of the present invention, the content of component (B) is preferably 0.1 to 50% by mass, more preferably 1 to 20% by mass, and even more preferably 5 to 15% by mass, relative to component (A).

[0151] The weight-average molecular weight Mw of component (B) is not particularly limited, but is preferably 700 to 2500, more preferably 1000 to 2000, and even more preferably 1500 to 1900.

[0152] In this invention, the weight-average molecular weight Mw is the polystyrene conversion value obtained by gel permeation chromatography (GPC).

[0153] <Ingredient (C)>

[0154] Component (C) is a solvent.

[0155] The protective film forming composition of the present invention can be prepared by dissolving the above-mentioned components in a solvent, preferably an organic solvent, and used in a uniform solution state.

[0156] As the organic solvent for the protective film forming composition of the present invention, any organic solvent capable of dissolving solid components such as component (A), component (B), and other arbitrarily selected solid components can be used without particular restriction. In particular, since the protective film forming composition of the present invention is used in a uniform solution state, it is recommended to use organic solvents generally used in photolithography processes, taking into account its coating performance.

[0157] Examples of organic solvents include, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, cycloheptanone, 4-methyl-2-pentanol, ethyl ethoxylate, 2-hydroxyethyl acetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate, butyl acetate, 2-heptanone, methoxycyclopentane, anisole, γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. These solvents can be used alone or in combination of two or more.

[0158] Preferred solvents include propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and cyclohexanone. Propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate are particularly preferred.

[0159] The solid content of the protective film forming composition of the present invention is typically 0.1 to 70% by mass, preferably 0.1 to 60% by mass. The solid content refers to the proportion of all components remaining after removing the solvent from the protective film forming composition. The proportion of component (A) in the solid content is preferably 1 to 99.9% by mass, more preferably 50 to 99.9% by mass, even more preferably 50 to 95% by mass, and particularly preferably 50 to 90% by mass.

[0160] <Ingredient (D)>

[0161] Component (D) is a curing catalyst.

[0162] Regarding the curing catalyst included as an arbitrary component in the composition for forming the protective film, both thermal acid-generating agents and photo-acid-generating agents can be used, but thermal acid-generating agents are preferred.

[0163] Examples of heat-generating acid agents include p-toluenesulfonic acid, trifluoromethanesulfonic acid, and pyridine. - p-Toluenesulfonate (pyridine) -p-Toluenesulfonic acid), pyridine Phenolsulfonic acid, pyridine - p-Hydroxybenzenesulfonic acid (p-phenolsulfonic acid pyridine) salt), pyridine - Sulfonic acid compounds and carboxylic acid compounds such as trifluoromethanesulfonic acid, salicylic acid, camphor sulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, benzene disulfonic acid, 1-naphthalene sulfonic acid, citric acid, benzoic acid, and hydroxybenzoic acid.

[0164] Examples of photoacid-generating agents include, Salt compounds, sulfonylimide compounds, and disulfonyldiazomethane compounds, etc.

[0165] As Salt compounds, for example, diphenyliodine Hexafluorophosphate, diphenyliodine Trifluoromethanesulfonate, diphenyliodine Nonafluoro-n-butane sulfonate, diphenyl iodide Perfluorooctane sulfonate, diphenyl iodide Camphor sulfonate, bis(4-tert-butylphenyl)iodine Camphor sulfonate and bis(4-tert-butylphenyl)iodine Iodine, such as trifluoromethanesulfonate Sulfonate compounds, and sulfonate compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluorobutane sulfonate, triphenylsulfonium camphor sulfonate and triphenylsulfonium trifluoromethane sulfonate.

[0166] Examples of sulfonylimide compounds include, for example, N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoron-butanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalenediformimide.

[0167] Examples of disulfonyldiazomethane compounds include, for example, bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0168] A single solidification catalyst may be used, or two or more may be used in combination.

[0169] When using a curing catalyst, the content of the curing catalyst relative to component (A) is, for example, 0.1% to 50% by mass, preferably 1% to 30% by mass.

[0170] (A method for manufacturing a protective film, a method for manufacturing a substrate with a protective film, a method for manufacturing a substrate with a resist pattern, and a method for manufacturing a semiconductor device)

[0171] The protective film of the present invention is a sintered product of a coated film formed by a protective film forming composition.

[0172] The method for manufacturing a substrate with a protective film according to the present invention includes the following steps: coating the protective film forming composition of the present invention onto a semiconductor substrate having a height difference and firing it to form a protective film.

[0173] The method for manufacturing a substrate with a resist pattern according to the present invention includes the following steps (1) to (2).

[0174] Step (1): A step in which the protective film forming composition of the present invention is coated onto a semiconductor substrate and fired to form a protective film as a photoresist underlayer.

[0175] Step (2): A process in which a resist film is formed directly on the protective film or through other layers, followed by exposure and development to form a resist pattern.

[0176] The method for manufacturing the semiconductor device of the present invention includes the following processes (A) to (D).

[0177] Process (A): Processing for forming a protective film on a semiconductor substrate on which an inorganic film has been formed on the surface using the protective film forming composition of the present invention.

[0178] Treatment (B): Treatment that forms a resist pattern directly on the protective film or through other layers.

[0179] Process (C): Dry etching of the protective film using the resist pattern as a mask to expose the surface of the inorganic film.

[0180] Processing (D): Using the dry-etched protective film as a mask, the inorganic film is wet-etched using a semiconductor wet etching solution.

[0181] Examples of semiconductor substrates for coating the protective film forming composition (resist underlayer film forming composition) of the present invention include, for example, silicon wafers, germanium wafers, and compound semiconductor wafers such as gallium arsenide, indium phosphide, gallium nitride, indium nitride, and aluminum nitride.

[0182] When using a semiconductor substrate on which an inorganic film has been formed on its surface, the inorganic film is formed by, for example, ALD (atomic layer deposition), CVD (chemical vapor deposition), reactive sputtering, ion plating, vacuum evaporation, or spin coating (SOG). Examples of such inorganic films include, for instance, polycrystalline silicon films, silicon oxide films, silicon nitride films, silicon oxynitride films, BPSG (boro-phosphorus silicon glass) films, titanium nitride films, titanium oxynitride films, tungsten nitride films, gallium nitride films, and gallium arsenide films.

[0183] The aforementioned semiconductor substrate can be a substrate with varying elevations, such as vias (holes) and trenches (grooves). For example, a via, when viewed from above, is approximately circular in shape, with a diameter of, for example, 0.5 nm to 50 nm and a depth of, 50 nm to 500 nm. A trench, for example, a groove (a recess in the substrate), has a width of 0.5 nm to 50 nm and a depth of 50 nm to 500 nm. The protective film forming composition (resist underlayer film forming composition) of the present invention can be embedded without defects such as pores (voids) even in substrates with varying elevations as described above. The absence of defects such as pores is an important characteristic for the next process in semiconductor manufacturing (wet etching / dry etching of the semiconductor substrate, resist patterning).

[0184] The protective film forming composition of the present invention is coated onto such a semiconductor substrate using a suitable coating method such as a spin coater or a coating machine. Then, the protective film is formed by baking using a heating means such as a hot plate. Baking conditions are appropriately selected from a baking temperature of 100°C to 400°C and a baking time of 0.3 minutes to 60 minutes. Preferably, the baking temperature is 120°C to 350°C and the baking time is 0.5 minutes to 30 minutes; more preferably, the baking temperature is 150°C to 300°C and the baking time is 0.8 minutes to 10 minutes. The thickness of the formed protective film is, for example, 0.001 μm to 10 μm, preferably 0.002 μm to 1 μm, and more preferably 0.005 μm to 0.5 μm. When the baking temperature is below the above range, crosslinking may become insufficient, making it difficult to obtain the protective film with resistance to resist solvents or alkaline hydrogen peroxide aqueous solutions. On the other hand, when the baking temperature is above the above range, the protective film may decompose due to heat.

[0185] A resist film is formed directly or via other layers on the protective film as described above, followed by exposure and development to form a resist pattern.

[0186] Exposure is performed using a mask (photomask) to form a prescribed pattern, employing, for example, i-rays, KrF excimer lasers, ArF excimer lasers, EUV (ultraviolet light), or EB (electron ray). An alkaline developer is used during development, with a development temperature appropriately selected from 5°C to 50°C and a development time from 10 seconds to 300 seconds. As an alkaline developer, aqueous solutions of bases such as inorganic bases (e.g., sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia), primary amines (e.g., ethylamine, n-propylamine), secondary amines (e.g., diethylamine, di-n-butylamine), tertiary amines (e.g., triethylamine, methyldiethylamine), alkanolamines (e.g., dimethylethanolamine, triethanolamine), quaternary ammonium salts (e.g., tetramethylammonium hydroxide, tetraethylammonium hydroxide), cyclic amines (e.g., pyrrole, piperidine), etc., can also be used. Furthermore, an appropriate amount of an alcohol such as isopropanol, or a nonionic surfactant, can be added to the aforementioned aqueous solutions of alkaline bases. Preferred developers among these are quaternary ammonium salts, more preferably tetramethylammonium hydroxide and choline. Furthermore, surfactants may be added to these developers. Alternatively, organic solvents such as butyl acetate may be used instead of alkaline developers to develop the portions of the photoresist where the alkaline dissolution rate is not improved.

[0187] Next, using the formed resist pattern as a mask, the protective film is dry-etched. At this time, if the inorganic film is formed on the surface of the semiconductor substrate, the surface of the inorganic film is exposed; if the inorganic film is not formed on the surface of the semiconductor substrate, the surface of the semiconductor substrate is exposed.

[0188] Furthermore, the desired pattern is formed by wet etching with a semiconductor wet etchant, using the dry-etched protective film (which, if a resist pattern remains on the protective film, is also used as a mask) as a mask.

[0189] As a wet etching solution for semiconductors, general solutions used for etching semiconductor wafers can be used, such as acidic or alkaline substances.

[0190] Examples of substances that exhibit acidity include, for example, hydrogen peroxide, hydrofluoric acid, ammonium fluoride, acidic ammonium fluoride, ammonium hydrogen fluoride, buffered hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, or mixtures thereof.

[0191] Examples of substances exhibiting alkalinity include alkaline hydrogen peroxide solution, which is produced by mixing organic amines such as ammonia, sodium hydroxide, potassium hydroxide, sodium cyanide, potassium cyanide, and triethanolamine with hydrogen peroxide water to achieve an alkaline pH. SC-1 (ammonia-hydrogen peroxide solution) is a specific example. Furthermore, substances that can achieve an alkaline pH, such as urea mixed with hydrogen peroxide water and heated to induce thermal decomposition of urea and generate ammonia, can also be used as wet etching solutions.

[0192] Among them, acidic hydrogen peroxide water or alkaline hydrogen peroxide water is preferred.

[0193] These solutions may contain additives such as surfactants.

[0194] The operating temperature of the wet etching solution for semiconductors is preferably 25°C to 90°C, and more preferably 40°C to 80°C. The wet etching time is preferably 0.5 minutes to 30 minutes, and more preferably 1 minute to 20 minutes.

[0195] Example

[0196] The present invention will now be described in detail by giving examples, but the present invention is not limited thereto.

[0197] The weight-average molecular weights of the polymers shown in the following examples in this specification are determined by gel permeation chromatography (hereinafter referred to as GPC). A Tosoh GPC apparatus was used in the determination, and the determination conditions are as follows.

[0198] GPC pillars: Shodex (registered trademark) KF803L, Shodex (registered trademark) KF802, Shodex (registered trademark) KF801 (manufactured by Resonac Co., Ltd.)

[0199] Column temperature: 40℃

[0200] Solvent: Tetrahydrofuran (THF)

[0201] Flow rate: 1.0 ml / min

[0202] Standard sample: Polystyrene (manufactured by Tosoh Corporation)

[0203] <Synthesis example 1>

[0204] The following ingredients were added: 90.0 g of diglycidyl methyl isocyanurate (product name: MeDGIC, manufactured by Shikoku Chemical Industry Co., Ltd., 29.9% wt% propylene glycol monomethyl ether solution), 17.09 g of succinic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), and tetrabutyl bromide. A reaction flask containing 2.73 g of propylene glycol monomethyl ether (PPD) and 123.8 g of propylene glycol monomethyl ether was heated and stirred at 100°C for 16 hours under a nitrogen atmosphere. The resulting product corresponds to the following formula (1o), and the weight-average molecular weight (Mw) obtained by GPC and converted to polystyrene is 954.

[0205]

[0206] <Example 1>

[0207] Add 4.78 g of a solution (solid content 16.5 by mass) of the reaction product (equivalent to the copolymer with a weight average molecular weight of 4500 as determined by GPC based on polystyrene) obtained by the method described in Synthesis Example 12 of WO2020 / 026834, and pyridine. A solution was prepared by mixing 0.030 g of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.040 g of tannic acid (the compound shown in formula (I) below, manufactured by Fujifilm Wako Pure Chemical Co., Ltd.), 0.00079 g of surfactant (product name: Megafack (registered trademark) R-40, manufactured by DIC Co., Ltd.), 1.9 g of propylene glycol monomethyl ether acetate, and 13.2 g of propylene glycol monomethyl ether. The solution was filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0208]

[0209] (In formula (I) above, G independently represents a hydrogen atom or a monovalent group as shown in formula (II) below.)

[0210] (In equation (II) above, n represents an integer from 0 to 3. The number of benzene rings in equation (I) above is 4 or more and 17 or less. * indicates a bonding bond.)

[0211] An example of the structure of tannic acid shown in formula (I) above is shown in formula (III) below.

[0212]

[0213] Formula (III) above refers to a compound in which all G in Formula (I) are monovalent groups as shown in Formula (II), and all n in Formula (II) are 1.

[0214] <Example 2>

[0215] Add 4.57 g of a solution (solid content 16.5 by mass) of the reaction product (equivalent to the copolymer of the above formula (1n) obtained by GPC with a weight average molecular weight of 4500 as determined by conversion to polystyrene) obtained by the method described in Synthesis Example 12 of WO2020 / 026834, and pyridine. A solution was prepared by mixing 0.028 g of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.076 g of tannic acid (the compound shown in formula (I) above, manufactured by Fujifilm Wako Pure Chemical Co., Ltd.), 0.00076 g of surfactant (product name: Megafack (registered trademark) R-40, manufactured by DIC Co., Ltd.), 1.9 g of propylene glycol monomethyl ether acetate, and 13.4 g of propylene glycol monomethyl ether. The solution was filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0216] <Example 3>

[0217] Pyridine was added to 4.84 g of the solution containing the reaction product (solid content 16.3% by mass) obtained in Synthesis Example 1. A solution was prepared by mixing 0.030 g of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.040 g of tannic acid (the compound shown in formula (I) above, manufactured by Fujifilm Wako Pure Chemical Co., Ltd.), 0.00079 g of surfactant (product name: Megafack (registered trademark) R-40, manufactured by DIC Co., Ltd.), 1.9 g of propylene glycol monomethyl ether acetate, and 13.2 g of propylene glycol monomethyl ether. The solution was filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0218] <Example 4>

[0219] Pyridine was added to 4.63 g of the solution containing the reaction product (solid content 16.3% by mass) obtained in Synthesis Example 1. A solution was prepared by mixing 0.028 g of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.076 g of tannic acid (the compound shown in formula (I) above, manufactured by Fujifilm Wako Pure Chemical Co., Ltd.), 0.00076 g of surfactant (product name: Megafack (registered trademark) R-40, manufactured by DIC Co., Ltd.), 1.9 g of propylene glycol monomethyl ether acetate, and 13.3 g of propylene glycol monomethyl ether. The solution was filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0220] <Comparative Example 1>

[0221] Pyridine was added to 5.01 g of a solution (solid content 16.5% by mass) of the reaction product (corresponding to the above formula (1n), a copolymer with a weight-average molecular weight of 4500 determined by GPC based on polystyrene) obtained by the method described in Synthesis Example 12 of WO2020 / 026834. A solution was prepared by mixing 0.031 g of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.00083 g of surfactant (product name: Megafack (registered trademark) R-40, manufactured by DIC Co., Ltd.), 13.0 g of propylene glycol monomethyl ether, and 1.91 g of propylene glycol monomethyl ether acetate. This solution was filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0222] <Comparative Example 2>

[0223] Pyridine was added to 4.78 g of a solution (solid content 16.5% by mass) of the reaction product (corresponding to the above formula (1n), a copolymer with a weight-average molecular weight of 4500 determined by GPC based on polystyrene) obtained by the method described in Synthesis Example 12 of WO2020 / 026834. A solution was prepared by mixing 0.030 g of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.040 g of gallic acid hydrate (hydrate of the compound shown in formula (3) below, manufactured by Tokyo Chemical Industry Co., Ltd.), 0.00079 g of surfactant (product name: Megafack (registered trademark) R-40, manufactured by DIC Co., Ltd.), 13.2 g of propylene glycol monomethyl ether, and 1.9 g of propylene glycol monomethyl ether acetate. The solution was filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0224]

[0225] <Comparative Example 3>

[0226] Add 4.78 g of a solution (solid content 16.5 by mass) of the reaction product (equivalent to the copolymer of the above formula (1n) obtained by GPC with a weight average molecular weight of 4500 as determined by conversion to polystyrene) obtained by the method described in Synthesis Example 12 of WO2020 / 026834, and pyridine. A solution was prepared by mixing 0.030 g of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.040 g of (2,3,4-trihydroxyphenyl)(3,4,5-trihydroxyphenyl) methyl ketone (the compound shown in formula (2) below, 2,3,3',4,4',5'-hexahydroxybenzophenone, also known as ethoxybenzone, HHBP. Manufactured by Tokyo Chemical Industry Co., Ltd.), 0.00079 g of surfactant (product name: Megafac (registered trademark) R-40, manufactured by DIC Co., Ltd.), 1.9 g of propylene glycol monomethyl ether acetate, and 13.2 g of propylene glycol monomethyl ether. The solution was filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0227]

[0228] <Comparative Example 4>

[0229] Add 4.57 g of a solution (solid content 16.5 by mass) of the reaction product (equivalent to the copolymer of the above formula (1n) obtained by GPC with a weight average molecular weight of 4500 as determined by conversion to polystyrene) obtained by the method described in Synthesis Example 12 of WO2020 / 026834, and pyridine. A solution was prepared by mixing 0.028 g of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.076 g of HHBP (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.00076 g of surfactant (product name: Megafack (registered trademark) R-40, manufactured by DIC Co., Ltd.), 1.91 g of propylene glycol monomethyl ether acetate, and 13.4 g of propylene glycol monomethyl ether. This solution was filtered using a polyethylene microfilter with a pore size of 0.02 μm to prepare a composition for forming a protective film.

[0230] (Coating formation)

[0231] [Tolerance test to alkaline hydrogen peroxide aqueous solution]

[0232] Protective films (coatings) were formed using the protective film forming compositions prepared in Examples 1-4 and Comparative Examples 1-4, and resistance tests to alkaline hydrogen peroxide aqueous solutions were conducted.

[0233] A summary of the tolerance test is shown below. Figures 1A to 1D middle.

[0234] like Figure 1A As shown, a silicon substrate 1 with a height difference (width 37nm, depth 240nm) was used as the semiconductor substrate, on which a titanium nitride (TiN) film with a thickness of 5nm was formed on the surface. Figure 1A As part of a silicon substrate, it has multiple height differences as described above.

[0235] Next, as Figure 1B As shown, the protective film forming compositions prepared in Examples 1-4 and Comparative Examples 1-4 were coated on the silicon substrate 1, and the coating (protective film 2) was formed by heating at 220°C for 60 seconds.

[0236] Next, as Figure 1C As shown, the formed protective film 2 was dry etched for 60 seconds using a dry etching apparatus (RIE-200NL, manufactured by Samko Co., Ltd.) with a N2 / O2 mixed gas (N2 / O2 volume ratio = 200 / 10). During this process, the protective film 2 was dry etched to expose the TiN on the wall surface within the height difference.

[0237] Next, 20 mL of 28% (w / w) ammonia solution, 80 mL of 33% (w / w) hydrogen peroxide solution, and 400 mL of ultrapure water were mixed to prepare an alkaline hydrogen peroxide solution. The silicon substrate 1, which had undergone dry etching, was immersed in the alkaline hydrogen peroxide solution heated to 60°C for 100 seconds for wet etching. After rinsing with water, the state of the dried protective film 2 was observed using a field emission scanning electron microscope (Regulus 8240) manufactured by Hitachi High-Tech Co., Ltd. (See attached image.) Figure 1D As shown, TiN was scraped down to a depth within the height difference compared to the protective film by wet etching. The results of the resistance test to alkaline hydrogen peroxide aqueous solution are shown in Table 1. In Table 1, "○" indicates a state in which no peeling of the protective film was observed after immersion, similar to Comparative Example 3, and "×" indicates a state in which peeling was observed in part or all of the protective film after immersion, which is a deterioration compared to Comparative Example 3.

[0238]

[0239] [Experimentation of optical parameters]

[0240] The protective film forming compositions prepared in Examples 1-4 and Comparative Examples 1-4 were respectively coated onto silicon wafers using a spin coater. After baking at 220°C for 1 minute on a hot plate, a resist underlayer film (film thickness 50 nm) was formed. Furthermore, the n-values ​​(refractive index) and k-values ​​(attenuation coefficient or absorption coefficient) at wavelengths of 193 nm and 248 nm were measured using a spectroscopic ellipsometry (JAWoollam, VUV-VASE VU-302). The results are shown in Table 2.

[0241]

[0242] [Determination of sublimation content]

[0243] The determination of sublimation content was performed using the apparatus described in International Publication No. 2007 / 111147.

[0244] Using a spin coater, the protective film forming compositions prepared in Examples 1-4 and Comparative Examples 1-4 were coated onto a 4-inch diameter silicon wafer substrate at 1500 rpm for 60 seconds. The wafer coated with the protective film forming compositions was placed in the above-mentioned sublimation measuring apparatus, which was integrated with a hot plate set to 220°C, and baked for 60 seconds. The sublimation was captured onto the QCM (Quartz Crystal Microbalance) sensor, i.e., the quartz resonator with electrodes formed thereon. The QCM sensor can measure minute mass changes by utilizing the property that the frequency of the quartz resonator changes (decreases) according to the mass of the sublimation adhering to the surface (electrode) of the quartz resonator.

[0245] The detailed measurement procedure is as follows. Heat the heating plate of the sublimation content measuring device to 220°C, and set the pump flow rate to 1 m³ / min. 3 The initial 60 seconds are set for device stabilization. Then, a wafer coated with a protective film-forming composition is immediately and rapidly placed onto the hot plate from the sliding port, and sublimation is collected for 60 to 120 seconds (60 seconds). Furthermore, the flow accessory (detection part) connecting the QCM sensor to the collection funnel in the aforementioned sublimation measurement device is used without a nozzle. Therefore, the airflow flows unobstructed from the flow path (orifice diameter: 32 mm) of the chamber unit, which is 30 mm away from the sensor (quartz resonator). Moreover, the QCM sensor uses a material with silicon and aluminum as the main components (AlSi (with Ti deposited on the surface)) as electrodes, the quartz resonator diameter (sensor diameter) is 14 mm, the electrode diameter on the quartz resonator surface is 5 mm, and the resonant frequency is 9 MHz.

[0246] In each measurement, to enable real-time measurement of sublimation content, the QCM sensor was connected directly to a personal computer via a serial cable and dedicated software was installed. Furthermore, the wafer used for sublimation content measurement had a coating thickness of 100 nm.

[0247] The obtained frequency change was converted to grams from the intrinsic value of the quartz resonator used in the measurement, thus clarifying the relationship between the amount of sublimation of a wafer coated with the protective film formation composition and the passage of time. Furthermore, the initial 60 seconds were the time for device stabilization (without the wafer), and the measurements taken from 60 seconds to 120 seconds after the wafer was placed on the hot plate were values ​​related to the amount of sublimation of the wafer. The amount of sublimation of the protective film quantified by the sublimation amount measuring device is shown in Table 3 as a sublimation amount ratio. The sublimation amount is calculated by setting the value of Comparative Example 3 to 1.0 and expressed as a relative value.

[0248]

[0249] As shown in Table 1, the protective films formed using the protective film forming compositions of Examples 1 to 4 of the present invention exhibit excellent drug resistance. In contrast, the protective films formed using the protective film forming composition of Comparative Example 1, which does not contain additives, exhibit poor drug resistance.

[0250] As shown in Table 2, it can be confirmed that the protective films formed using the protective film forming compositions of Examples 1 to 4 of the present invention have performance that is not problematic as anti-reflective films.

[0251] As shown in Table 3, it can be confirmed that the amount of sublimation in the protective film formed using the protective film forming compositions of Examples 1 to 4 of the present invention can be reduced by 20% to 60% compared with the protective film formed using the protective film forming composition of Comparative Example 3, which does not contain component (B) of the additive.

[0252] Industry availability

[0253] The protective film forming composition of the present invention provides a protective film with excellent resistance to wet etching solution when processing a substrate and low amount of sublimation during firing.

[0254] Explanation of symbols

[0255] 1. Silicon substrate

[0256] 2. Protective film.

Claims

1. A composition for forming a protective film with a wet etching solution for semiconductors, comprising: Component (A): Membrane-forming component; Component (B): A selection of condensed tannins (b1) formed by the polymerization of compounds with a flavanol skeleton, hydrolyzed tannins (b2) formed by the ester bonding of aromatic compounds of gallic acid or ellagic acid with sugars, and compounds derived from flavonoids (b3) having a flavanone skeleton; and Component (C): Solvent.

2. The composition for forming a protective film according to claim 1, wherein component (B) is one or more compounds selected from the condensed tannin and the hydrolyzed tannin.

3. The composition for forming a protective film according to claim 1, wherein component (B) is the hydrolyzable tannin.

4. The composition for forming a protective film according to claim 3, wherein the hydrolyzable tannin is tannic acid as shown in formula (I). In formula (I), G independently represents a hydrogen atom or a monovalent group as shown in formula (II) below; In equation (II), n represents an integer from 0 to 3; where, The number of benzene rings in formula (I) is more than 4 and less than 17; * indicates a bonding bond.

5. The protective film forming composition according to claim 1, further comprising component (D): a curing catalyst.

6. The composition for forming a protective film according to claim 1, wherein the content of component (B) is 0.1 to 50% by mass relative to the mass of the solid component (A).

7. A protective film for a wet etching solution for semiconductors, which is a sintered product of a coating film formed by any one of claims 1 to 6.

8. A method for manufacturing a substrate with a protective film for manufacturing semiconductors, comprising the step of coating a protective film forming composition according to any one of claims 1 to 6 onto a semiconductor substrate and firing it to form a protective film.

9. A method for manufacturing a substrate with a resist pattern for manufacturing semiconductors, comprising the following steps: The process of forming a protective film as a resist underlayer by coating the protective film forming composition according to any one of claims 1 to 6 onto a semiconductor substrate and firing it; and A photoresist film is formed directly on the protective film or through other layers, followed by exposure and development to form a photoresist pattern.

10. A method for manufacturing a semiconductor device, comprising the steps of: forming a protective film on a semiconductor substrate on which an inorganic film can be formed using a protective film forming composition according to any one of claims 1 to 6; forming a resist pattern on the protective film; dry etching the protective film using the resist pattern as a mask to expose the inorganic film or the surface of the semiconductor substrate; and wet etching and washing the inorganic film or the semiconductor substrate using a semiconductor wet etching solution as a mask.

Images