Positive photosensitive resin composition, insulating resin film, method of forming insulating resin film, and semiconductor device

Abstract

A positive photosensitive resin composition comprising: (A) an alkali-soluble resin having a phenolic hydroxyl group; (B) an oxazoline compound having a plurality of oxazoline groups; (C) a photoacid generator containing a compound that generates an acid when exposed to light; and (D) an alkoxy compound having a plurality of alkoxy groups.

Description

Positive photosensitive resin composition, insulating resin film, method for forming insulating resin film, and semiconductor device

[0001] The present disclosure relates to a positive photosensitive resin composition, an insulating resin film having a pattern including openings, a method for forming an insulating resin film having a pattern including openings, and a semiconductor device.

[0002] Patent Document 1 discloses a positive photosensitive resin composition containing an alkali-soluble resin having an imide bond and a phenolic hydroxyl group as a material capable of forming a surface protective layer or an interlayer insulating layer of a semiconductor element.

[0003] International Publication No. 2021 / 261448

[0004] The present disclosure relates to a positive photosensitive resin composition capable of forming an insulating resin film that exhibits excellent chemical resistance and sufficiently large elongation at break.

[0005] The present disclosure includes the following: [1] A positive photosensitive resin composition comprising: (A) an alkali-soluble resin having a phenolic hydroxyl group; (B) an oxazoline compound having a plurality of oxazoline groups; (C) a photoacid generator that is a compound that generates an acid by exposure to light; and (D) an alkoxy compound having a plurality of alkoxy groups. [2] The oxazoline compound is selected from the group consisting of the following (1): wherein Z represents a direct bond, an aromatic group which may have a substituent, or an alicyclic group which may have a substituent. [3] The positive photosensitive resin composition according to [1] or [2], wherein at least a portion of the plurality of alkoxy groups is a methoxy group. [4] The positive photosensitive resin composition according to [3], wherein the alkoxy compound has a plurality of methoxyalkyl groups each containing the methoxy group and an aromatic group, and the methoxyalkyl groups are bonded to the aromatic group. [5] The positive photosensitive resin composition according to [4], wherein the alkoxy compound further has a phenolic hydroxyl group bonded to the aromatic group. [6] The positive photosensitive resin composition according to any one of [1] to [5], wherein the content of the oxazoline compound is 50% by mass or less relative to the content of the alkoxy compound. [7] The positive photosensitive resin composition according to any one of [1] to [6], wherein the content of the alkoxy compound is 1% by mass or more and 50% by mass or less relative to the content of the alkali-soluble resin. [8] A method for forming an insulating resin film, comprising: exposing a part of a photosensitive layer containing the positive photosensitive resin composition according to any one of [1] to [7]; forming an insulating resin film having a pattern including openings by developing to remove part of the photosensitive layer; and heating the insulating resin film. [9] An insulating resin film, comprising a cured product of the positive photosensitive resin composition according to any one of [1] to [7], and having a pattern including openings.

[10] A semiconductor device, comprising: a semiconductor chip; and a wiring part including a conductor wiring layer connected to the semiconductor chip and one or more insulating layers, wherein at least a part of the one or more insulating layers is the insulating resin film according to [9].

[0006] The positive photosensitive resin composition according to the present disclosure can provide an insulating resin film that has a pattern including openings and exhibits excellent chemical resistance and sufficiently large elongation at break.

[0007] 1 is a flowchart showing an example of a method for forming an insulating resin film having a pattern.

[0008] The present invention is not limited to the following examples. In this disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended function of the process is achieved. The term "layer" encompasses not only a structure that is formed over the entire surface when observed in a plan view, but also a structure that is formed only on a portion of the surface. Numerical ranges indicated using "to" indicate ranges that include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a numerical range of a certain stage may be replaced with the upper or lower limit of a numerical range of another stage. In numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with the value shown in the examples.

[0009] Photosensitive Resin Composition An example of a photosensitive resin composition includes (A) an alkali-soluble resin having a phenolic hydroxyl group, (B) an oxazoline compound having multiple oxazoline groups, (C) a photoacid generator that generates an acid when exposed to light, and (D) an alkoxy compound having multiple alkoxy groups. The photosensitive resin composition according to the present disclosure can function as a positive photosensitive resin composition based on a change in solubility in an alkaline developer upon exposure to light. Furthermore, a film containing the photosensitive resin composition according to the present disclosure can be cured, mainly by the oxazoline compound and the alkoxy compound functioning as thermal crosslinkers, to form an insulating resin film that is a cured film containing a cured product of the photosensitive resin composition.

[0010] (A) Alkali-Soluble Resin The alkali-soluble resin of component (A) can be a resin having a phenolic hydroxyl group, in other words, a polymer containing a structural unit having a phenolic hydroxyl group. Alkali-soluble resins having a phenolic hydroxyl group are excellent in terms of high resolution and contrast in pattern formation.

[0011] In the present disclosure, an alkali-soluble resin refers to a resin that dissolves in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) at 25° C. Whether a resin is alkali-soluble can be confirmed by a method that includes forming a resin film of the resin having a thickness of about 1 μm on a substrate and immersing the resin film in a 2.38% by mass aqueous solution of TMAH at 25° C. For example, if the resin film completely dissolves in the TMAH aqueous solution within 60 minutes of immersion while the TMAH aqueous solution is left stationary, the resin is considered to be an alkali-soluble resin.

[0012] The alkali-soluble resin having a phenolic hydroxyl group may have a structural unit (residue) derived from a phenol which may have a substituent. Examples of phenol derivatives, which are phenols having a substituent, include o-cresol, m-cresol, p-cresol, and p-hydroxystyrene. The alkali-soluble resin may be a novolak resin, which is a product of the reaction of a phenolic compound containing a phenol which may have a substituent with one or more reactive compounds selected from an aldehyde compound, a compound having multiple methoxymethyl groups, and a compound having multiple hydroxymethyl groups.

[0013] The aldehyde compound constituting the novolac resin may be formaldehyde. The compound having multiple methoxymethyl groups may be a compound having an aromatic ring (e.g., a benzene ring) to which methoxymethyl groups are bonded. The compound having multiple hydroxymethyl groups may be a compound having an aromatic ring (e.g., a benzene ring) to which hydroxymethyl groups are bonded. Examples of compounds having multiple methoxymethyl groups include compounds represented by the following formula (11) or (12). In these formulas, R １１ and R １２ represents an alkyl group having 1 to 3 carbon atoms (e.g., a methyl group). １１ and R １２may be the same or different. p represents an integer of 0 to 4, and q and r each independently represent an integer of 0 to 4. The compound having multiple methoxymethyl groups may be bis(methoxymethyl)biphenyl, dimethoxymethylbenzene, or a combination thereof. An example of a compound having multiple hydroxymethyl groups includes 2,6-bis(hydroxymethyl)-p-cresol.

[0014] The alkali-soluble novolak resin may have a polymer chain in which structural units (residues) derived from a phenolic compound selected from phenol, o-cresol, m-cresol, and p-cresol are alternately bonded with structural units (residues) derived from a reactive compound selected from an aldehyde compound, a compound having multiple methoxymethyl groups, and a compound having multiple hydroxymethyl groups. The structural unit (residue) derived from a phenolic compound may be a residue obtained by removing a hydrogen atom from the phenolic compound at the ortho- or para-position relative to the phenolic hydroxyl group. The residue derived from an aldehyde compound is usually a methylene group. The residue derived from a compound having two or more methoxymethylaryl groups may be, for example, a divalent group represented by the following formula (11A) or (12B). R in formulas (11A) and (12B) １１ , R １２ , p, q and r are R in formulas (11) and (12). １１ , R １２ , p, q and r.

[0015] The alkali-soluble resin may be a copolymer containing p-hydroxystyrene as a monomer unit, and an example of the copolymer is a p-hydroxystyrene-styrene copolymer.

[0016] The alkali-soluble resin may further have an imide group. In other words, the alkali-soluble resin may be a polymer having a structural unit having an imide group. The alkali-soluble resin having an imide group can contribute to improving the mechanical strength of an insulating resin film formed from the photosensitive resin composition. The alkali-soluble resin may contain an aromatic group, an alicyclic group, or both, and the imide group may form a condensed ring with the aromatic group or the alicyclic group.

[0017] The alkali-soluble resin having an imide group may be a novolak resin containing a structural unit (residue) derived from a bisphenolimide compound, which is a phenol derivative having a phenolic hydroxyl group and an imide group. The bisphenolimide compound may be a reaction product of a tetracarboxylic dianhydride and an aminophenol compound, examples of which include compounds represented by the following formula (I) or (II):

[0018] In these formulas, R １ and R ２ represents a hydrogen atom or a methyl group. １ and R ２ may be the same or different. ａ represents a divalent organic group or a direct bond. ａ may be a divalent group selected from an oxy group (-O-), a thio group (-S-), a carbonyl group, an alkylene group having 1 to 3 carbon atoms, a phenylene group, an alkylphenylene group, and groups consisting of combinations thereof, or a direct bond. Examples of alkylene groups having 1 to 3 carbon atoms include a methylene group, an ethylene group, an ethylidene group, a propylene group (propane-1,3-diyl group), a propylidene group (propane-1,1-diyl group), and an isopropylidene group (propane-2,2-diyl group). R ａ Specific examples of the divalent group as R include the following: ａ may be an oxy group or a carbonyl group.

[0019] In these formulas, R ３ , R ４ , R ５ , and R６ Each independently represents an alkyl group (e.g., a methyl group). ３ , R ４ , R ５ , and R ６ may be the same or different. p represents an integer of 0 to 4, q and r each independently represent an integer of 0 to 4, s represents an integer of 0 to 4, and t and u each independently represent an integer of 0 to 4. R ｂ and R ｃ represents an alkylene group (e.g., propane-2,2-diyl group, methylene group), an oxy group, a thio group, or a direct bond. ｄ represents an alkylene group (for example, an ethane-1,2-diyl group).

[0020] In the bisphenolimide compound represented by formula (I) or (II), from the viewpoint of improving solubility in solvents, at least one of the two phenolic hydroxyl groups may be bonded to the meta- or ortho-position relative to the imide group. Examples of bisphenolimide compounds represented by formula (I) in which the phenolic hydroxyl group is bonded to the meta- or ortho-position relative to the imide group include compounds represented by formula (Ia), (Ib), (Ic), or (Id) below. Examples of bisphenolimide compounds represented by formula (II) in which the phenolic hydroxyl group is bonded to the meta- or ortho-position relative to the imide group include compounds represented by formula (IIa), (IIb), (IIc), or (IId) below. These compounds tend to have an excellent balance between solubility and mechanical strength. R in formulas (IIa), (IIb), (IIc), and (IId) ａ is R in formula (II). ａ is synonymous with.

[0021] The novolak resin containing a structural unit (residue) derived from a bisphenolimide compound may have a polymer chain in which a residue derived from a phenolic compound selected from phenol, o-cresol, m-cresol, and p-cresol, or a bisphenolimide compound is alternately bonded with a structural unit (residue) derived from a reactive compound selected from an aldehyde compound, a compound having multiple methoxymethyl groups, and a compound having multiple hydroxymethyl groups. The structural unit (residue) derived from a bisphenolimide compound may be a residue in which one or more hydrogen atoms have been removed from an aromatic group (particularly a benzene ring to which a phenolic hydroxyl group is bonded) in the bisphenolimide compound. The structural unit (residue) derived from the bisphenolimide compound may be bonded to another structural unit at the ortho- or para-position relative to the phenolic hydroxyl group.

[0022] The novolac resin, which is an alkali-soluble resin, can be synthesized, for example, by a method similar to the method for synthesizing a general phenol novolac resin or cresol novolac resin.

[0023] The weight average molecular weight (Mw) of the alkali-soluble resin may be 1,000 to 500,000, 2,000 to 400,000, 3,000 to 350,000, or 5,000 to 300,000, from the viewpoint of the balance between solubility in an alkaline aqueous solution, photosensitive properties, and mechanical strength of the insulating resin film. In the present disclosure, the weight average molecular weight is a converted value measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

[0024] The alkali-soluble resin may have molecular chains derived from an elastomer, examples of which will be described later.

[0025] (B) Oxazoline Compound The oxazoline compound of component (B) is a compound having two or more oxazoline groups represented by the following formula. It is believed that the oxazoline compound functions mainly as a thermal crosslinking agent that crosslinks molecular chains of the alkali-soluble resin through a reaction between a phenolic hydroxyl group and an oxazoline group. The number of oxazoline groups possessed by the oxazoline compound may be 2 to 5, 2 to 4, 2 to 3, or 2.

[0026] The oxazoline compound may be a compound represented by the following formula (1): In formula (1), Z represents a direct bond, an aromatic group which may have a substituent, or an alicyclic group which may have a substituent.

[0027] The aromatic group represented by Z may be a phenylene group (e.g., a 1,3-phenylene group). The alicyclic group represented by Z may be, for example, a cyclohexanediyl group. The substituent that can be bonded to the aromatic group or the alicyclic group may be, for example, an alkyl group (e.g., a methyl group).

[0028] Specific examples of the oxazoline compound include compounds represented by the following formula (1a) or (1b).

[0029] From the viewpoint of achieving both improved chemical resistance and alkali solubility, the content of the oxazoline compound may be 50% by mass or less, or may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more, relative to the content of the alkoxy compound.

[0030] (C) Photoacid Generator The photoacid generator (C) contains one or more compounds that generate an acid upon exposure to light (e.g., ultraviolet light) and functions as a photosensitizer in the photosensitive resin composition. The action of the acid generated by the photoacid generator upon absorption of light selectively increases the solubility in an alkaline aqueous solution of the portion of the photosensitive layer that has been irradiated with light.

[0031] The compound constituting the photoacid generator may be selected from compounds generally used as photoacid generators. The compound that generates an acid when exposed to light may be, for example, an o-quinonediazide compound, an aryldiazonium salt, a diaryliodonium salt, or a triarylsulfonium salt, or a combination of two or more selected from these.

[0032] In order to improve the sensitivity of exposure, the photoacid generator may contain an o-quinone diazide compound. The o-quinone diazide compound contains an aromatic group, an oxo group (=O), and a diazide group (=N). ＋ = N －) in which an oxo group and a diazido group are bonded to adjacent carbon atoms in an aromatic group. The aromatic group may be, for example, a group obtained by removing a hydrogen atom from naphthalene or benzene.

[0033] The o-quinonediazide compound may have, as a group containing an oxo group and a diazide group, a group represented by the following formula (3a), (3b) or (3c), for example.

[0034] The compound having a group represented by formula (3a), (3b), or (3c) may be, for example, a product of a condensation reaction between o-quinone diazide sulfonyl chloride and a hydroxy compound and / or an amino compound in the presence of a dehydrochlorinating agent. In this case, the o-quinone diazide compound may be a compound having a residue derived from a hydroxy compound or an amino compound and a group represented by formula (3a), (3b), or (3c). For example, a compound having a group represented by formula (3a) can be obtained from naphthoquinone-1,2-diazide-5-sulfonyl chloride. A compound having a group represented by formula (3b) can be obtained from naphthoquinone-1,2-diazide-6-sulfonyl chloride. A compound having a group represented by formula (3c) can be obtained from benzoquinone-1,2-diazide-4-sulfonyl chloride.

[0035] Hydroxy compounds that can be used to synthesize o-quinone diazide compounds are compounds having one or more hydroxyl groups. The residue of a hydroxy compound can be a group obtained by removing one or more hydrogen atoms from the hydroxyl group of a hydroxy compound. Examples of hydroxy compounds include hydroquinone, resorcinol, pyrogallol, bisphenol A, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)-1-[4-{1-(4-hydroxyphenyl)-1-methylethyl}phenyl]ethane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,3,4-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, and 2,2',4,4'-tetrahydroxybenzophenone. phenone, 2,3,4,2',3'-pentahydroxybenzophenone, 2,3,4,3',4',5'-hexahydroxybenzophenone, bis(2,3,4-trihydroxyphenyl)methane, bis(2,3,4-trihydroxyphenyl)propane, 4b,5,9b,10-tetrahydro-1,3,6,8-tetrahydroxy-5,10-dimethylindeno[2,1-a]indene, tris(4-hydroxyphenyl)methane, and tris(4-hydroxyphenyl)ethane.

[0036] Specific examples of the compound having a residue of a hydroxy compound and a group represented by formula (3a), (3b), or (3c) include compounds represented by the following formulas (31), (32), (33), (34), (35), or (36). These compounds tend to absorb light in an appropriate wavelength range for exposure of the photosensitive layer.

[0037] In formulas (31) to (36), Q represents a group represented by formula (3a), (3b), or (3c), or a hydrogen atom, and multiple Qs in the same molecule may be the same or different, and at least one of the multiple Qs in the same molecule is a group represented by formula (3a), (3b), or (3c). ３０ represents an alkyl group having 1 to 3 carbon atoms (e.g., a methyl group), and multiple R３０ may be the same or different. ３１ represents an alkanetriyl group having 1 to 3 carbon atoms (for example, a methanetriyl group or an ethane-1,1,1-triyl group), and each of the multiple p's independently represents an integer of 0 to 4. In formula (32), each of the multiple q's independently represents an integer of 0 to 4. In formula (33), each of the multiple r's independently represents an integer of 0 to 4, and each of the multiple s's independently represents an integer of 0 to 3. In formula (34), each of the multiple t's independently represents an integer of 0 to 4. In formula (35), each of the multiple u's independently represents an integer of 0 to 4, and each of the multiple v's independently represents an integer of 0 to 3. In formula (36), w represents an integer of 0 to 4, and x represents an integer of 0 to 2.

[0038] The amino compound that can be used to synthesize the o-quinonediazide compound is a compound having one or more amino groups. The residue of the amino compound can be a group in which one or more hydrogen atoms have been removed from the amino group of the amino compound. Examples of the amino compound include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, o-aminophenol, m-aminophenol, p-aminophenol, 3,3'-diamino-4,4'-dihydroxybiphenyl, 4,4'-diamino-3,3'-dihydroxybiphenyl, bis(3-amino-4-hydroxyphenyl)propane, bis(4-amino-3-hydroxyphenyl)propane, bis(3-amino-4-hydroxyphenyl)sulfone, bis(4-amino-3-hydroxyphenyl)sulfone, bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and bis(4-amino-3-hydroxyphenyl)hexafluoropropane.

[0039] From the viewpoint of good sensitivity, the content of the photoacid generator may be 1 to 50 mass %, 3 to 35 mass %, or 5 to 20 mass % relative to the content of the alkali-soluble resin of the component (A).

[0040] (D) Alkoxy Compound The alkoxy compound of component (D) is thought to function as a thermal crosslinking agent that crosslinks the molecular chains of the alkali-soluble resin mainly through the reaction of an aromatic group (phenylene group) to which a phenolic hydroxyl group is bonded with an alkoxy group. The combination of an oxazoline compound and an alkoxy compound can contribute to improving the breaking elongation and chemical resistance of the insulating resin film (cured film), as well as, for example, improving the sensitivity of exposure and development, improving mechanical strength, and improving heat resistance. The number of alkoxy groups in the alkoxy compound may be 2 or more, 3 or more, or 4 or more, and may be 20 or less, 15 or less, or 10 or less.

[0041] At least a portion of the two or more alkoxy groups of the alkoxy compound may be methoxy groups. In other words, the alkoxy compound may have multiple methoxy groups. The alkoxy compound may have four or more methoxy groups.

[0042] The alkoxy compound may have a cyclic group obtained by removing one or more hydrogen atoms from benzene, 1,3,5-triazine, glycoluril, 2-imidazolidinone, or urea, and an alkoxyalkyl group (e.g., a methoxymethyl group or a 1,3-dimethoxypropan-2-yl group) may be bonded to the cyclic group. An alkoxy compound having a cyclic group (benzene ring) obtained by removing a hydrogen atom from benzene may have a phenolic hydroxyl group bonded to the cyclic group. In the present disclosure, a compound having an alkoxy group and a phenolic hydroxyl group may be considered to be an alkoxy compound of component (D) rather than an alkali-soluble resin. An alkoxy compound having an alkoxy group and a phenolic hydroxyl group may contribute to improving the sensitivity of the photosensitive resin composition.

[0043] The weight average molecular weight of the alkoxy compound may be 3000 or less, 2000 or less, or 1500 or less, or may be 100 or more, from the viewpoint of the balance of solubility in an alkaline developer, photosensitive properties, and mechanical strength.

[0044] Specific examples of alkoxy compounds having a phenolic hydroxyl group include compounds represented by the following formula (41), (42), (43), (44), (45), or (46). Specific examples of alkoxy compounds having a cyclic group formed by removing one or more hydrogen atoms from 1,3,5-triazine, glycoluril, 2-imidazolidinone, or urea include compounds represented by the following formula (47), (48), (49), or (50).

[0045] In formulas (41) to (50), R ４０ represents an alkoxyalkyl group, and multiple R ４０ may be the same or different. ４０ may be a methoxyalkyl group or a dimethoxyalkyl group, an example of which is a methoxymethyl group (-CH ２ OCH ３ ), and a 1,3-dimethoxypropan-2-yl group represented by the following formula:

[0046] From the viewpoint of the heat resistance of the insulating resin film (cured film) and suppression of warpage, the content of the alkoxy compound may be 1 to 70 mass %, 2 to 50 mass %, or 3 to 40 mass % relative to the content of the alkali-soluble resin of the component (A).

[0047] In the photosensitive resin composition, the total content of the (A) alkali-soluble resin, (B) oxazoline compound, (C) photoacid generator, and (D) alkoxy compound may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the amount of the photosensitive resin composition. When the photosensitive resin composition contains a solvent, the amount of the photosensitive resin composition herein is the amount excluding the solvent.

[0048] Other Components In addition to components (A) to (D), the photosensitive resin composition may further contain other components such as an elastomer, an adhesion aid, a solvent, a compound that generates an acid upon heating, a dissolution promoter, a dissolution inhibitor, a Cu rust inhibitor, a coupling agent, a surfactant, and a leveling agent. The photosensitive resin composition may further contain, in addition to component (A), an alkali-soluble resin that does not fall under component (A).

[0049] The elastomer may be, for example, one or more selected from styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers, and silicone-based elastomers.

[0050] The elastomer may be an acrylic elastomer containing a (meth)acrylic acid alkyl ester as a monomer unit. The (meth)acrylic acid alkyl ester may have an alkyl group having 1 to 20 carbon atoms. The acrylic elastomer may further contain, as a monomer unit, one or more acrylic monomers selected from (meth)acrylic acid, an aliphatic alcohol and ester having an amino group, a (meth)acrylic acid alkyl ester having a hydroxyalkyl group having 4 to 20 carbon atoms, and (meth)acrylic acid. The content of the elastomer may be 0 to 50 mass%, 0.5 to 50 mass%, 1 to 30 mass%, or 2 to 20 mass% relative to the amount of the alkali-soluble resin. "(Meth)acrylic acid" means acrylic acid or methacrylic acid.

[0051] The adhesion promoter may include a nitrogen-containing aromatic compound, examples of which include 1H-tetrazole, 5-aminotetrazole, 5-phenyltetrazole, and 5-methyltetrazole. The content of the adhesion promoter may be 0 to 20 mass%, 0.01 to 20 mass%, 0.015 to 10 mass%, or 0.02 to 7 mass% relative to the content of the alkali-soluble resin of component (A).

[0052] Examples of solvents include γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether acetate, benzyl acetate, n-butyl acetate, ethoxyethyl propionate, 3-methylmethoxypropionate, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphorylamide, tetramethylene sulfone, diethyl ketone, diisobutyl ketone, methyl amyl ketone, cyclohexanone, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol monomethyl ether. These solvents can be used alone or in combination of two or more. The solvent may include ethyl lactate, γ-butyrolactone, or a combination thereof. In a photosensitive resin composition containing a solvent, the concentration of components other than the solvent (solid content) may be 1 to 80% by mass based on the mass of the photosensitive resin composition containing the solvent.

[0053] The compound that generates an acid upon heating promotes the thermal crosslinking reaction between the alkali-soluble resin and the oxazoline compound or alkoxy compound, which can result in further improved heat resistance of the cured film. The compound that generates an acid upon heating can also contribute to improved resolution. Examples of the compound that generates an acid upon heating include salts formed from a strong acid and a base, such as onium salts, and imide sulfonates. The content of the compound that generates an acid upon heating may be 0 to 30% by mass, 0.1 to 30% by mass, 0.2 to 20% by mass, or 0.5 to 10% by mass relative to the content of the alkali-soluble resin of component (A).

[0054] The dissolution promoter is a component that increases the dissolution rate of the exposed area in a developer, and can contribute to improving sensitivity and resolution. The dissolution promoter may include a compound having a carboxy group, a sulfo group, or a sulfonamide group. The content of the dissolution promoter may be 0 to 30% by mass, or 0.01 to 30% by mass, relative to the content of the alkali-soluble resin of component (A).

[0055] The dissolution inhibitor is a compound that inhibits the dissolution of exposed areas in an alkaline aqueous solution and is used to control the film thickness, development time, and contrast after development. Examples of dissolution inhibitors include diphenyliodonium nitrate, bis(p-tert-butylphenyl)iodonium nitrate, diphenyliodonium bromide, diphenyliodonium chloride, and diphenyliodonium iodide. The content of the dissolution inhibitor may be 0 to 20% by mass, 0.01 to 20% by mass, 0.01 to 15% by mass, or 0.05 to 10% by mass relative to the content of the alkali-soluble resin of component (A).

[0056] The coupling agent may include an organic silane compound (silane coupling agent), an aluminum chelate compound, or a combination thereof. Examples of commercially available organic silane compounds include KBM-403, KBM-803, and KBM-903 (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.). The content of the coupling agent may be 0 to 20% by mass, 0.1 to 20% by mass, or 0.5 to 10% by mass relative to the content of the alkali-soluble resin of component (A).

[0057] Examples of surfactants or leveling agents include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene octylphenol ether. Examples of commercially available products include Megafac F-171, F-565, and RS-78 (trade names, manufactured by DIC Corporation). The content of the surfactant or leveling agent may be 0 to 5 mass%, 0.001 to 5 mass%, or 0.01 to 3 mass%, relative to the content of the alkali-soluble resin of component (A).

[0058]

[0023] Method for forming an insulating resin film having a pattern including openings can be formed by photolithography using the photosensitive resin composition according to the present disclosure. Fig. 1 is a flowchart showing an example of a method for forming an insulating resin film having a pattern including openings. The method shown in Fig. 1 includes a step S1 of forming a photosensitive layer including the photosensitive resin composition, a step S2 of exposing a portion of the photosensitive layer to light, a step S3 of removing a portion of the photosensitive layer through development to form an insulating resin film having a pattern including openings, and a step S4 of heating the insulating resin film.

[0059] The photosensitive layer containing the photosensitive resin composition can be applied to, for example, a glass substrate, a semiconductor substrate, a metal oxide insulating substrate (e.g., TiO ２ , SiO ２ The photosensitive layer may be formed on any substrate, such as a silicon nitride substrate. The photosensitive layer may be formed, for example, by a method including coating a solvent-containing positive photosensitive resin composition on the substrate and removing the solvent from the coating. The coating may be heated to remove the solvent. The thickness of the photosensitive layer may be 0.1 to 40 μm.

[0060] A portion of the photosensitive layer is exposed by irradiation with actinic rays through a mask. The actinic rays may be ultraviolet light, visible light, or radioactive rays, and may be g-rays, h-rays, i-rays, or a combination thereof.

[0061] By developing to remove a portion of the photosensitive layer, a resin film (insulating resin film) having a pattern including openings is formed. A developer may be used for the development. Examples of development using a developer include shower development, spray development, immersion development, and puddle development. The resin film (insulating resin film) after development may be washed with water or the like.

[0062] The developer may be an alkaline aqueous solution. The alkaline aqueous solution may contain one or more bases selected from sodium carbonate, sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, and tetramethylammonium hydroxide (TMAH). The concentration of the base in the alkaline aqueous solution may be 0.1 to 10% by mass based on the mass of the alkaline aqueous solution. The developer may contain alcohol or a surfactant.

[0063] By heating the developed resin film (insulating resin film), an insulating resin film containing a cured product of the photosensitive resin composition is formed. This heating can cause a thermal crosslinking reaction between the alkali-soluble resin and the oxazoline compound and the alkoxy compound. The heating temperature may be 300°C or lower, 270°C or lower, or 250°C or lower, or may be 160°C or higher. The heating time may be, for example, 0.5 hours or longer and 5 hours or shorter.

[0064] The resin film (insulating resin film) can be heated using a heating device such as a quartz tube furnace, a hot plate, a rapid thermal annealer, a vertical diffusion furnace, an infrared curing furnace, an electron beam curing furnace, a microwave curing furnace, a microwave curing device, a frequency-variable microwave curing device, etc. The heating atmosphere may be, for example, an air atmosphere or an inert gas atmosphere containing nitrogen or the like.

[0065] The insulating resin film may be, for example, an insulating layer constituting a wiring portion of a semiconductor device. The semiconductor device may have a semiconductor chip, a conductor wiring layer connected to the semiconductor chip, and a wiring portion (rewiring portion) including one or more insulating layers, and at least a portion of the one or more wiring layers may be an insulating resin film including a cured product of the photosensitive resin composition according to the present disclosure.

[0066] FIG. 2 is a partial cross-sectional view showing an example of a semiconductor device having an insulating layer. The semiconductor device 100 shown in FIG. 2 includes a semiconductor chip 10 and a wiring section 20 provided on the semiconductor chip 10. The wiring section 20 includes a conductor wiring layer 31 connected to the semiconductor chip 10, a surface protective layer 41, a cover coat layer 42, and conductive balls 50. The semiconductor device 100 may be a semiconductor package having a wafer-level package (WLP) configuration. The surface protective layer 41 and the cover coat layer 42 are stacked in this order from the semiconductor chip 10 side, and the conductive balls 50 are provided outside the cover coat layer 42. The surface protective layer 41 and the cover coat layer 42 are insulating layers, and one or both of them may be an insulating resin film containing a cured product of the photosensitive resin composition according to the present disclosure.

[0067] The semiconductor chip 10 has a chip main body 11 having a circuit surface, pads 12 provided on the circuit surface of the chip main body 11, and a protective film 13 having a pattern including openings through which the pads 12 are exposed. The conductor wiring layer 31 of the wiring section 20 is a rewiring layer connected to the pads 12 and extends to the inside of the conductive balls 50 between a surface protective layer 41 and a cover coat layer 42. A connection section 32 for connecting to the conductive balls 50 is provided on an end of the conductor wiring layer 31. A barrier metal 33 is provided between the connection section 32 and the conductive balls 50. The pads 12, conductor wiring layer 31, connection section 32, barrier metal 33, and conductive balls 50 are electrically connected in this order.

[0068] The wiring portion (rewiring portion) of the semiconductor device may have multiple conductor wiring layers, and an insulating resin film containing a cured product of the photosensitive resin composition according to the present disclosure may be provided as an interlayer insulating layer provided between adjacent conductor wiring layers. In the semiconductor device, the interlayer insulating layer, the surface protective layer, or both of them may be an insulating resin film containing a cured product of the photosensitive resin composition according to the present disclosure.

[0069] The semiconductor device may be a memory. Examples of electronic devices including the semiconductor device according to the present disclosure include mobile phones, smartphones, tablet terminals, personal computers, and hard disk drives.

[0070] The present invention is not limited to the following examples.

[0071] 1. Raw materials The following raw materials were prepared: (A) Alkali-soluble resins A1: bisphenolimide-cresol novolac resin (an acid-catalyzed reaction product of N,N'-bis(3-hydroxyphenyl)-pyromellitimide, o-cresol, m-cresol, 1,4-bis(methoxymethyl)benzene, and formaldehyde (molar ratio: 10:60:30:30:70), weight-average molecular weight: 150,000) A2: p-hydroxystyrene-styrene copolymer (p-hydroxystyrene / styrene=85 / 15 (molar ratio), Maruzen Petrochemical Co., Ltd., trade name "Maruka Linker CST85", weight-average molecular weight: 10,000) A3: bisphenolimide novolac resin (an acid-catalyzed reaction product of bis(2-hydroxyphenyl)4,4'-oxyphthalimide and 1,4-bis(methoxymethyl)benzene (molar ratio: 50:50), weight-average molecular weight: 42,000) (B) Oxazoline compounds B1: 2,2'-(1,3-phenylene)bis(2-oxazoline) (compound of formula (1a), manufactured by Tokyo Chemical Industry Co., Ltd.) B2: 2,2'-bis(2-oxazoline) (compound of formula (1b), manufactured by Tokyo Chemical Industry Co., Ltd.) (C) Photoacid Generator C1: 1-naphthoquinone-2-diazide-5-sulfonic acid ester of 1,1-bis(4-hydroxyphenyl)-1-[4-{1-(4-hydroxyphenyl)-1-methylethyl}phenyl]ethane (esterification rate: approximately 90%, manufactured by Daito ChemiX Co., Ltd., trade name "PA28") C2: 1-naphthoquinone-2-diazide-5-sulfonic acid ester of bis[3-(4-hydroxybenzyl)-4-hydroxy-2,5-dimethylphenyl]methane (esterification rate: approximately 75%, manufactured by Toyo Gosei Co., Ltd., trade name "CNB300") (D) Alkoxy compound D1: 4,4'-[1-[4-[1-[4-hydroxy-3,5-bis(methoxymethyl)phenyl]-1-methylethyl]phenyl]ethylidene]bis[2,6-bis(methoxymethyl)phenol] (represented by formula (42), R ４０is a methoxymethyl group, manufactured by Honshu Chemical Industry Co., Ltd., trade name "HMOM-TPPA") D2: 2,2-bis(4-hydroxy-3,5-dimethoxymethyl-phenyl)propane (represented by formula (44), R ４０(E) Elastomer E1: Acrylic elastomer prepared by the following method: 55 g of ethyl lactate was weighed out into a 100 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a thermometer, and separately weighed polymerizable monomers (32.0 g of n-butyl acrylate (BA), 0.9 g of lauryl acrylate (LA), 5.2 g of acrylic acid (AA), 2.6 g of hydroxybutyl acrylate (HBA), and 4.3 g of 1,2,2,6,6-pentamethylpiperidin-4-yl methacrylate (trade name: FA-711MM, manufactured by Resonac Corporation) and 0.30 g of azobisisobutyronitrile (AIBN) were added. The mixture was stirred at a rotation speed of approximately 160 rpm at room temperature, and nitrogen gas was passed through at a flow rate of 400 mL / min for 30 minutes to remove dissolved oxygen. The nitrogen gas flow was then stopped, the flask was sealed, and the temperature was raised to 65°C in approximately 25 minutes in a thermostatic water bath. The same temperature was maintained for 10 hours to carry out the polymerization reaction, yielding an acrylic elastomer. The conversion was 99%. The weight-average molecular weight of the resulting acrylic elastomer was approximately 12,000. The copolymerization ratio of the polymerizable monomers in the resulting acrylic elastomer was as follows: BA / LA / AA / HBA / FA-711MM = 69 / 1 / 20 / 5 / 5 (mol%) E2: Acrylic elastomer prepared by the following method Into a 100 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a thermometer, 55 g of ethyl lactate was weighed out, and separately weighed polymerizable monomers (34.5 g of n-butyl acrylate (BA), 1.8 g of N-acryloyloxyethylhexahydrophthalimide (trade name M-140, Toa Gosei Co., Ltd.), 4.7 g of acrylic acid (AA), 3.6 g of 1,4-cyclohexadimethanol monoacrylate (CHDMMA), and 2,2,6, 0.4 g of 6-tetramethylpiperidin-4-yl methacrylate (product name: FA-712HM, manufactured by Resonac Corporation) and 0.30 g of azobisisobutyronitrile (AIBN) were added. While stirring at a rotation speed of approximately 160 rpm at room temperature, nitrogen gas was passed through at a flow rate of 400 mL / min for 30 minutes to remove dissolved oxygen. Thereafter, the flow of nitrogen gas was stopped, the flask was sealed, and the temperature was raised to 65°C in a thermostatic water bath over approximately 25 minutes.The same temperature was maintained for 10 hours to carry out a polymerization reaction, yielding an acrylic elastomer. The polymerization rate was 99%. The weight-average molecular weight of the resulting acrylic elastomer was approximately 26,000. The copolymerization ratio of the polymerizable monomers in the resulting acrylic elastomer was as follows: BA / M-140 / AA / CHDMMA / FA-712HM = 74.5 / 2 / 18 / 5 / 0.5 (mol %) (F) Silane coupling agent F1: 3-glycidyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM403").

[0072] 2. Photosensitive Resin Composition Each component was mixed with ethyl lactate in the blending ratio (parts by mass) shown in Table 1. Only in the case of the photosensitive resin composition of Example 8 containing the alkali-soluble resin A3, each component was mixed with γ-butyrolactone instead of ethyl lactate. The mixture was pressure-filtered through a polytetrafluoroethylene filter with 0.2 μm pores to prepare a photosensitive resin composition.

[0073] 3. Evaluation Pattern Formation Test The photosensitive resin composition was applied to a silicon substrate by spin coating. The coating was heated at 120°C for 3 minutes to remove the ethyl lactate or γ-butyrolactone, forming a photosensitive layer with a film thickness of 5 to 6 μm. Next, using an i-line stepper (Canon, product name "FPA-3000iW"), the photosensitive layer was subjected to reduced projection exposure with i-line (365 nm) through a mask having a pattern corresponding to a square hole (opening) having a size of 20 μm x 20 μm. The i-line exposure dose was 1000 mJ / cm ２ After exposure, a portion of the photosensitive layer was removed by development using a 2.38% TMAH aqueous solution. The remaining photosensitive layer, which was the insulating resin film, was washed with water. The insulating resin film was observed, and the pattern formation performance of the photosensitive resin composition was evaluated based on the state of formation of the square holes and the presence or absence of peeling or residual dissolution of the insulating resin film, using the following criteria: A: Holes were properly formed, and no peeling of the insulating resin film or residual dissolution in the holes was observed. B: Holes were properly formed, but peeling of the insulating resin film or residual dissolution in the holes was observed. C: Holes were not properly formed.

[0074] Chemical Resistance The photosensitive resin composition was applied to a silicon substrate by spin coating. The coating was heated at 120°C for 3 minutes to form a photosensitive layer with a thickness of 5.5 to 6 μm. The formed photosensitive layer was heated in an inert gas oven (INH-9CD-S) under a nitrogen atmosphere, raised to 230°C over 1 hour, and maintained at 230°C for 2 hours to form a cured insulating resin film with a thickness of approximately 5 μm.

[0075] The cured film was cut together with the silicon substrate to separate into 2 cm square test pieces (laminates of silicon substrate and cured film). The test pieces were immersed in N-methylpyrrolidone (NMP) or dimethyl sulfoxide (DMSO) heated to 65°C for 30 minutes. After immersion, the test pieces were observed to check for peeling of the cured film from the silicon substrate and the presence or absence of cracks in the cured film. The thickness of the cured film after immersion was also measured, and the rate of change in thickness was calculated based on the thickness before immersion (5 μm). Based on these results, the chemical resistance was evaluated according to the following criteria: A: No peeling or cracking of the cured film was observed, and the rate of change in thickness before and after immersion was within 7%. B: No peeling or cracking of the cured film was observed, and the rate of change in thickness before and after immersion was within 15%. C: No peeling or cracking of the cured film was observed, and the rate of change in thickness before and after immersion was within 25%. D: Peeling or cracking of the cured film was observed.

[0076] Breaking elongation and breaking strength of insulating resin film (cured film) The photosensitive resin composition was applied to a silicon substrate by spin coating. The coating was heated at 120°C for 3 minutes to form a photosensitive layer with a film thickness of 8 to 9 μm. Next, the photosensitive layer was exposed to light of all wavelengths through a mask using an aligner (manufactured by SUSS MicroTec K.K., product name "MA-8"). The exposure dose was 1500 mJ / cm. ２After exposure, an insulating resin film having a pattern including 10 mm-wide linear portions was formed by development using a 2.38% TMAH aqueous solution. The formed insulating resin film was heated in an inert gas oven (INH-9CD-S) under a nitrogen atmosphere, with the temperature increased to 230°C over 1 hour and maintained at 230°C for 2 hours, thereby promoting curing of the insulating resin film. The thickness of the cured insulating resin film after heating was approximately 7 μm.

[0077] A 10 mm wide strip-shaped test piece was prepared from the cured film peeled from the silicon substrate. A tensile test of the test piece was performed using an autograph AGS-100NX manufactured by Shimadzu Corporation. In the tensile test, the chuck distance was 20 mm, the tensile speed was 5 mm / min, and the measurement environment temperature was room temperature (20°C to 25°C). From the results of the tensile test, the average values ​​of the top three values ​​measured for five test pieces obtained from cured films prepared under the same conditions were recorded as the breaking elongation and breaking strength.

[0078] Glass Transition Temperature (Tg) of Insulating Resin Film (Cured Film) The glass transition temperature (Tg) of a cured film formed under the same conditions as the cured film for measuring breaking elongation and breaking strength was measured by thermomechanical analysis using a TMA / 7100 (manufactured by Hitachi High-Tech Corporation). The sample used for the measurement had a width of 4 mm and a film thickness of approximately 7 μm. The measurement conditions were as follows: Chuck distance: 10 mm, Load: 10 gf, Heating rate: 5°C / min

[0079]

[0080]

[0081] As shown in Tables 1 and 2, it was confirmed that the photosensitive resin compositions of the examples, which contain (A) an alkali-soluble resin having a phenolic hydroxyl group, (B) an oxazoline compound having multiple oxazoline groups, (C) a photoacid generator containing a compound that generates an acid when exposed to light, and (D) an alkoxy compound having multiple alkoxy groups, can form insulating resin films that exhibit excellent chemical resistance and sufficiently large elongation at break. The photosensitive resin compositions of the examples were also excellent in that they were able to form good patterns even with a small amount of exposure light, and in that the insulating resin films after heating exhibited good breaking strength and heat resistance.

[0082] 10...semiconductor chip, 11...chip main body portion, 12...pad portion, 13...protective film, 20...wiring portion, 31...conductor wiring layer, 32...connection portion, 33...barrier metal, 41...surface protection layer (insulating layer), 42...cover coat layer (insulating layer), 50...conductive ball, 100...semiconductor device

Claims

1. A positive photosensitive resin composition comprising: (A) an alkali-soluble resin having a phenolic hydroxyl group; (B) an oxazoline compound having a plurality of oxazoline groups; (C) a photoacid generator which is a compound that generates an acid upon irradiation with light; and (D) an alkoxy compound having a plurality of alkoxy groups.

2. The oxazoline compound is the following (1): The positive photosensitive resin composition according to claim 1, which is a compound represented by the formula, and Z represents a direct bond, an aromatic group which may have a substituent, or an alicyclic group which may have a substituent.

3. The positive photosensitive resin composition according to claim 1, wherein at least a part of the plurality of alkoxy groups is a methoxy group.

4. The positive photosensitive resin composition according to claim 3, wherein the alkoxy compound has a plurality of methoxyalkyl groups containing the methoxy group and an aromatic group, and the methoxyalkyl group is bonded to the aromatic group.

5. The positive photosensitive resin composition according to claim 4, wherein the alkoxy compound further has a phenolic hydroxyl group bonded to the aromatic group.

6. The positive photosensitive resin composition according to claim 1, wherein the content of the oxazoline compound is 50% by mass or less with respect to the content of the alkoxy compound.

7. The positive photosensitive resin composition according to claim 1, wherein the content of the alkoxy compound is 1% by mass or more and 50% by mass or less with respect to the content of the alkali-soluble resin.

8. A method for forming an insulating resin film, comprising: exposing a part of a photosensitive layer containing the positive photosensitive resin composition according to any one of claims 1 to 7; forming an insulating resin film having a pattern including an opening by development to remove a part of the photosensitive layer; and heating the insulating resin film.

9. An insulating resin film comprising a cured product of the positive photosensitive resin composition according to any one of claims 1 to 7 and having a pattern including an opening.

10. A semiconductor device comprising: a semiconductor chip; and a wiring portion including a conductor wiring layer connected to the semiconductor chip and one or more insulating layers, wherein at least a part of the one or more insulating layers is the insulating resin film according to claim 9.

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