JP2023050691A - Negative photosensitive resin composition, cured film, and semiconductor device - Google Patents

Abstract

To provide a negative photosensitive resin composition having low-temperature curability, and a cured film excellent in strength obtained by curing the same.SOLUTION: The negative photosensitive resin composition to be used for a rewiring layer of a semiconductor device contains (A) a phenolic resin, (B) a crosslinking agent, and (C) a photosensitizer. The phenolic resin (A) contains a biphenyl type phenolic resin. The crosslinking agent (B) contains a tetrafunctional urea resin-based crosslinking agent and a bifunctional epoxy resin-based crosslinking agent. A cured product of the negative photosensitive resin composition has a storage modulus at 250°C measured by dynamic mechanical analysis (DMA) of 2,500 MPa or less.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a negative photosensitive resin composition, a cured film made of a cured product thereof, and a semiconductor device provided with the cured film.

In the electrical and electronic fields, a photosensitive resin composition containing a thermosetting resin is sometimes used to form a cured film such as an insulating layer. Therefore, a photosensitive resin composition containing a thermosetting resin has been studied so far. It is known to form an insulating film in a rewiring layer and an insulating film in a portion other than the rewiring layer from a photosensitive resin composition containing a thermosetting resin.

As an example, Patent Document 1 describes a photosensitive resin composition containing an alkaline aqueous solution-soluble resin, a cross-linking agent, a photopolymerization initiator, and an epoxy resin (thermosetting resin) represented by a specific general formula. . Patent Document 1 describes that the photosensitivity of this photosensitive resin composition is good. Further, Patent Document 1 describes that a film formed from this photosensitive resin composition is excellent in flexibility, adhesion, pencil hardness, solvent resistance, acid resistance, heat resistance, gold plating resistance, and the like. there is

JP 2016-80871 A

As electronic devices become more advanced and complicated, electronic devices are required to be more reliable than ever before. Therefore, it is desired to improve the reliability of electronic devices by improving the cured film and the photosensitive resin composition for forming the cured film. Further, in recent years, in order to reduce thermal damage to semiconductor chips, it has been required to relatively lower the heating temperature (for example, about 200° C.) when forming a cured film.

The present invention has been made in view of the above problems, and is a negative photosensitive resin composition containing a phenol resin, a photosensitive agent, and a photosensitive agent, by using a combination of a specific phenol resin and a specific cross-linking agent. The present inventors have found that the strength of the cured film obtained by curing the composition is excellent while being curable at a low temperature, and have completed the present invention.

According to the invention,
A negative photosensitive resin composition used in a rewiring layer of a semiconductor device,
The negative photosensitive resin composition is
(A) a phenolic resin,
(B) a cross-linking agent, and (C) a photosensitizer,
The phenolic resin (A) includes a biphenyl-type phenolic resin,
The cross-linking agent (B) includes a bifunctional or more functional urea resin cross-linking agent and a bi- or more functional epoxy resin cross-linking agent,
Provided is a negative photosensitive resin composition having a storage elastic modulus at 250° C. measured by dynamic viscoelasticity measurement (DMA) of 2500 MPa or less when the negative photosensitive resin composition is cured. be.

Moreover, according to this invention, the cured film obtained by hardening the said negative photosensitive resin composition is provided.

Furthermore, according to the present invention,
a semiconductor element;
and a rewiring layer provided on the surface of the semiconductor element,
A semiconductor device is provided in which the insulating layer in the rewiring layer is composed of the cured film.

ADVANTAGE OF THE INVENTION According to this invention, the negative photosensitive resin composition which has low-temperature curability, and the cured film excellent in intensity|strength obtained by hardening this are provided.

1 is a cross-sectional view showing a configuration example of a semiconductor device according to an embodiment; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In this specification, the numerical range "x to y" represents "x or more and y or less" and includes both the lower limit value x and the upper limit value y. For example, "1 to 5% by mass" means "1% by mass or more and 5% by mass or less". Further, in the drawings below, the same constituent elements are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Also, the drawings are schematic diagrams and do not correspond to actual dimensional ratios.

In the description of a group (atomic group) in the present specification, a description without indicating whether it is substituted or unsubstituted includes both those having no substituent and those having a substituent. For example, the term “alkyl group” includes not only alkyl groups without substituents (unsubstituted alkyl groups) but also alkyl groups with substituents (substituted alkyl groups).

[Negative photosensitive resin composition]
The negative photosensitive resin composition of this embodiment is a resin material used for forming a rewiring layer of a semiconductor device. The negative photosensitive resin composition of the present embodiment contains (A) a phenolic resin, (B) a cross-linking agent, and (C) a photosensitive agent,
The phenolic resin (A) contains a biphenyl-type phenolic resin,
The cross-linking agent (B) includes a bifunctional or more functional urea resin cross-linking agent and a bi- or more functional epoxy resin cross-linking agent.
The storage elastic modulus at 250° C. measured by dynamic viscoelasticity measurement (DMA) when the negative photosensitive resin composition of the present embodiment is cured is 2500 MPa or less.

In the present embodiment, the storage elastic modulus is obtained by measuring the dynamic viscoelasticity of a cured film obtained by heating a negative photosensitive resin composition at 180°C for 2 hours under the following conditions. is the storage modulus.
(conditions)
Frequency: 1Hz
Temperature: 30-300°C
Heating rate: 5°C/min Measurement mode: Tensile mode

The present inventor conducted studies to improve the low-temperature curability of the negative photosensitive resin composition and to improve the strength of the resulting cured film. As a result, the negative photosensitive resin composition contains a specific component, and the storage elastic modulus of the cured film of the negative photosensitive resin composition is in a specific range. found to be resolved.

The storage elastic modulus of the cured film at 250° C. is preferably 2200 MPa or less, more preferably 2000 MPa or less. The lower limit of the storage elastic modulus of the cured film at 250°C is, for example, 1400 MPa or more, preferably 1600 MPa or more.

The storage elastic modulus of the negative photosensitive resin composition of the present embodiment can be adjusted by selecting each component used therein and its compounding amount.

Next, each component will be described in more detail.
(Phenolic resin (A))
The negative photosensitive resin composition of the present embodiment contains a biphenyl-type phenolic resin (a1) as the phenolic resin. As the biphenyl-type phenol resin (a1), a phenol resin having a structural unit represented by the following formula (2) is preferable from the viewpoint of improving the curability at low temperature and the reliability of the cured film.

In formula (2) above, R ₄₁ and R ₄₂ each independently represent a hydroxyl group, a halogen atom, a carboxyl group, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms, or an alkyl ether having 1 to 20 carbon atoms. group, a saturated or unsaturated alicyclic group having 3 to 20 carbon atoms, or a monovalent substituent selected from the group consisting of an organic group having an aromatic structure having 6 to 20 carbon atoms, and these are ester bonds. , an ether bond, an amide bond, or a carbonyl bond, r and s are each independently an integer of 0 to 3, and Y ₄ and Z ₄ are each independently , a single bond, or an organic group having an aliphatic group having 1 to 10 carbon atoms which may have an unsaturated bond, an alicyclic group having 3 to 20 carbon atoms, and an aromatic structure having 6 to 20 carbon atoms and Z ₄ is attached to either one of the two benzene rings.

Specifically, the biphenyl-type phenol resin (a1) having the structural unit represented by formula (2) can be obtained using the method described in JP-A-2018-155938.

The content of the biphenyl-type phenol resin (a1) in the negative photosensitive resin composition of the present embodiment is such that when the total solid content of the negative photosensitive resin composition is 100 parts by mass, From the viewpoint of improving properties, the amount is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 15 parts by mass or more.
Further, from the viewpoint of deterioration of toughness, the content of the biphenyl-type phenol resin (a1) in the negative photosensitive resin composition is preferably It is 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less.

From the viewpoint of improving the curability at low temperatures and the reliability of the cured film, the negative photosensitive resin composition of the present embodiment may further contain a phenol resin (a2) other than the biphenyl-type phenol resin (a1) described above. good.
Specific examples of the phenolic resin (a2) include novolac-type phenolic resins such as phenolic novolak resins, cresol novolac resins, bisphenol novolac resins, phenol-biphenyl novolac resins, allylated novolak-type phenolic resins, and xylylene novolac-type phenolic resins; reaction products of phenolic compounds such as novolak-type phenolic resins, resol-type phenolic resins and cresol novolac resins and aldehyde compounds; and reaction products of phenolic compounds such as phenol-aralkyl resins and dimethanol compounds.

Among them, the phenol resin (a2) is preferably a resin having a structure represented by the following formula (1) from the viewpoint of obtaining a low-temperature curable resin composition.

In the above formula (1), n is preferably 6 or more, more preferably 10 or more, still more preferably 14 or more, from the viewpoint of improving curability at low temperatures.
From the viewpoint of solvent solubility, n is preferably 72 or less, more preferably 54 or less, and even more preferably 36 or less.

The weight average molecular weight of the biphenyl-type phenol resin (a2) may be, for example, 500 or more, preferably 2000 or more, more preferably 3000 or more, and still more preferably 4000 or more, from the viewpoint of improving curability at low temperatures. is.
Further, the weight average molecular weight of the biphenyl-type phenol resin (a2) may be, for example, 50000 or less, preferably 20000 or less, more preferably 15000 or less, still more preferably 10000 or less from the viewpoint of solvent solubility. .

When the negative photosensitive resin composition contains the biphenyl-type phenolic resin (a2), the content thereof is 100 parts by mass based on the total solid content of the negative photosensitive resin composition, from the viewpoint of improving toughness during low-temperature curing. Then, it is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 15 parts by mass or more.
Further, from the viewpoint of the mechanical properties of the resulting cured film, the content of the biphenyl-type phenolic resin (a2) in the negative photosensitive resin composition is 100 parts by mass based on the total solid content of the negative photosensitive resin composition. , it is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less.

The negative photosensitive resin composition of the present embodiment may contain thermosetting resins other than phenolic resins. Specific examples of such resins include phenol resins other than the biphenyl-type phenol resins described above, hydroxystyrene resins, polyamide resins, polybenzoxazole resins, polyimide resins, and cyclic olefin resins.

Further, the content of the phenol resin (A) in the negative photosensitive resin composition, when the total solid content of the photosensitive resin composition is 100 parts by mass, the curability at low temperature and the reliability of the cured film. From the viewpoint of improvement, it is preferably 30 parts by mass or more, more preferably 45 parts by mass or more, even more preferably 50 parts by mass or more, and even more preferably 55 parts by mass or more.
Further, from the viewpoint of improving chemical resistance and photosensitivity, the content of component (A) in the photosensitive resin composition is preferably 95 parts by mass when the total solid content of the photosensitive resin composition is 100 parts by mass. parts or less, more preferably 90 parts by mass or less, and even more preferably 85 parts by mass or less. Here, the phenolic resin (A) is the total amount of phenolic resins used in the negative photosensitive resin composition of the present embodiment, and the phenolic resin (A) is the biphenyl-type phenolic resin (a1) described above, and It consists of a phenolic resin (a2) used as needed.

(Crosslinking agent (B))
The negative photosensitive resin composition of the present embodiment contains, as the cross-linking agent (B), a bifunctional or more functional urea resin cross-linking agent (b1) and a bi- or more functional epoxy resin cross-linking agent (b2). The negative photosensitive resin composition of the present embodiment is excellent in curability at low temperature by containing such a cross-linking agent.

Examples of the bifunctional or higher functional urea resin-based cross-linking agent (b1) used as a cross-linking agent in the negative photosensitive resin composition of the present embodiment include di- to tetra-functional alkoxymethylated glycoluril compounds. An alkoxymethylated glycoluril compound refers to a compound in which a hydrogen atom of an amino group of a glycoluril compound is substituted with an alkoxymethylol group. Specific examples of alkoxymethylated glycoluril include 1,3,4,6-tetrakis(methoxymethyl)glycoluril, 1,3,4,6-tetrakis(butoxymethyl)glycoluril, 1,3,4 ,6-tetrakis(hydroxymethyl)glycoluril, 1,3-bis(hydroxymethyl)urea, 1,1,3,3-tetrakis(butoxymethyl)urea, 1,1,3,3-tetrakis(methoxymethyl) urea, 1,3-bis(hydroxymethyl)-4,5-dihydroxy-2-imidazolinone, 1,3-bis(methoxymethyl)-4,5-dimethoxy-2-imidazolinone and the like.

As the bifunctional or higher epoxy resin-based crosslinking agent (b2) used as a crosslinking agent in the negative photosensitive resin composition of the present embodiment, it is preferable to use a bifunctional phenoxy-type epoxy resin. Bifunctional phenoxy type epoxy resins include bisphenol A type phenoxy resin, bisphenol F type phenoxy resin, bisphenol S type phenoxy resin, bisphenol acetophenone type phenoxy resin, novolac type phenoxy resin, biphenyl type phenoxy resin, fluorene type phenoxy resin, dicyclo Pentadiene-type phenoxy resins, norbornene-type phenoxy resins, naphthalene-type phenoxy resins, anthracene-type phenoxy resins, adamantane-type phenoxy resins, terpene-type phenoxy resins, trimethylcyclohexane-type phenoxy resins, and the like can be used. Specific examples of such phenoxy resins include resins JER-1256, YX-7105 (manufactured by Mitsubishi Chemical Corporation) and LX-01 (manufactured by Osaka Soda Co., Ltd.).

The cross-linking agent (B) is a range that does not impair the low-temperature curability of the negative photosensitive resin composition, and includes the above-mentioned bifunctional or higher urea resin cross-linking agent (b1) and bi- or higher functional epoxy resin cross-linking agent (b2 ) in addition to other cross-linking agents (b3). Examples of other cross-linking agents (b3) include 1,2-benzenedimethanol, 1,3-benzenedimethanol, 1,4-benzenedimethanol (paraxylene glycol), and 1,3,5-benzenetrimethanol. , 4,4-biphenyldimethanol, 2,6-pyridinedimethanol, 2,6-bis(hydroxymethyl)-p-cresol, 4,4′-methylenebis(2,6-dialkoxymethylphenol) and other methylols Phenols such as phloroglucide; 1,4-bis(methoxymethyl)benzene, 1,3-bis(methoxymethyl)benzene, 4,4'-bis(methoxymethyl)biphenyl, 3,4'- Having an alkoxymethyl group such as bis(methoxymethyl)biphenyl, 3,3'-bis(methoxymethyl)biphenyl, methyl 2,6-naphthalenedicarboxylate, 4,4'-methylenebis(2,6-dimethoxymethylphenol) Compounds; methylolmelamine compounds represented by hexamethylolmelamine, hexabutanolmelamine, etc.; alkoxymelamine compounds such as hexamethoxymelamine; methylolbenzoguanamine compounds, methylolurea compounds such as dimethylolethyleneurea; alkylated urea resins; dicyanoaniline, dicyano cyano compounds such as phenol and cyanophenylsulfonic acid; isocyanate compounds such as 1,4-phenylene diisocyanate and 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate; ethylene glycol diglycidyl ether, bisphenol A Epoxy group-containing compounds such as diglycidyl ether, triglycidyl isocyanurate, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, phenol novolak resin type epoxy resin; ,3-phenylenedimaleimide, N,N'-methylenedimaleimide and other maleimide compounds.

The content of the bifunctional or higher urea resin-based cross-linking agent (b1) is preferably 80 mass from the viewpoint of improving toughness during low-temperature curing when the total solid content of the negative photosensitive resin composition is 100 mass parts. parts or more, more preferably 85 parts by mass or more, and still more preferably 90 parts by mass or more.
In addition, from the viewpoint of maintaining thermomechanical properties during low-temperature curing, the content of the tetrafunctional urea resin-based cross-linking agent (b1) in the negative photosensitive resin composition is 100% of the total solid content of the photosensitive resin composition. When expressed as parts by mass, it is preferably 140 parts by mass or less, more preferably 120 parts by mass or less, and even more preferably 110 parts by mass or less.

The content of the bifunctional or higher epoxy resin-based cross-linking agent (b2) is preferably 20 mass parts from the viewpoint of improving the toughness during low-temperature curing when the total solid content of the negative photosensitive resin composition is 100 mass parts. parts or more, more preferably 25 parts by mass or more, and still more preferably 30 parts by mass or more.
In addition, from the viewpoint of maintaining the thermomechanical properties during low-temperature curing, the content of the bifunctional or higher epoxy resin-based cross-linking agent (b2) in the negative photosensitive resin composition is adjusted to the total solid content of the photosensitive resin composition. is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and even more preferably 60 parts by mass or less.

The content of the cross-linking agent (B) in the negative photosensitive resin composition of the present embodiment is, when the total solid content of the negative photosensitive resin composition is 100 parts by mass, to improve the toughness during low-temperature curing. From the viewpoint, it is preferably 120 parts by mass or more, more preferably 140 parts by mass or more, and still more preferably 160 parts by mass or more.
In addition, from the viewpoint of maintaining thermomechanical properties during low-temperature curing, the content of the cross-linking agent (B) in the negative photosensitive resin composition is 100 parts by mass based on the total solid content of the negative photosensitive resin composition. Then, it is preferably 250 parts by mass or less, more preferably 220 parts by mass or less, and even more preferably 200 parts by mass or less. Here, the cross-linking agent (B) includes the above-mentioned tetrafunctional urea resin-based cross-linking agent (b1), bifunctional or higher epoxy resin-based cross-linking agent (b2), and other cross-linking agents (b3) used as necessary. consists of

(Photosensitizer (C))
The negative photosensitive resin composition of the present embodiment contains a photosensitive agent (C) from the viewpoint of stably forming a cured film. The photosensitive agent (C) is specifically an acid generator that generates acid by absorbing thermal energy or light energy.

From the viewpoint of improving low-temperature curability and chemical resistance, the photosensitive agent (C) preferably contains a sulfonium compound or its salt (c1).
The sulfonium compound or its salt (c1) is specifically a sulfonium salt having a sulfonium ion as a cation moiety. At this time, the anion portion of the sulfonium compound or its salt (c1) is specifically boride ion, antimony ion, phosphorus ion or sulfonate ion such as trifluoromethanesulfonate ion, which improves the reaction rate at low temperature. from the viewpoint of reducing ions, boride ions or antimony ions are preferred, and boride ions are more preferred. These anions may have substituents.

The sulfonium compound or its salt (c1) preferably includes a sulfonium salt represented by the following formula (4).

In general formula (4) above, R ¹ is a hydrogen atom or a monovalent organic group, preferably a hydrogen atom or an acyl group, more preferably an acyl group, from the viewpoint of improving reactivity at low temperatures. , and more preferably a CH ₃ C(=O)- group.
R ² is a monovalent organic group, preferably a hydrocarbon group having a chain or branched chain or a benzyl group optionally having a substituent, from the viewpoint of improving reactivity at low temperatures, more preferably is a benzyl group optionally substituted with an alkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or a benzyl group in which the aromatic ring portion may be substituted with a methyl group is the base.
R ³ is a monovalent organic group, preferably a chain or branched hydrocarbon group, more preferably an alkyl group having 1 to 4 carbon atoms, from the viewpoint of improving reactivity at low temperatures. and more preferably a methyl group.

Other preferred examples of component (c1) include triphenylsulfonium salts such as triphenylsulfonium trifluoromethanesulfonate.

When the negative photosensitive resin composition contains a photosensitive agent (C), the content thereof improves the curability at low temperatures when the total solid content of the negative photosensitive resin composition is 100 parts by mass. From the viewpoint, it is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and still more preferably 0.02 parts by mass or more.
Further, from the viewpoint of suppressing a decrease in reliability, the content of the photosensitive agent (C) in the negative photosensitive resin composition is preferably 20 when the total solid content of the photosensitive resin composition is 100 parts by mass. It is not more than 18 parts by mass, more preferably not more than 16 parts by mass.

(adherence aid)
The negative photosensitive resin composition of the present embodiment preferably contains an adhesion aid. Thereby, for example, the adhesion to the substrate can be further enhanced.

The adhesion aid is not particularly limited. For example, amino group-containing silane coupling agents, epoxy group-containing silane coupling agents, (meth)acryloyl group-containing silane coupling agents, mercapto group-containing silane coupling agents, vinyl group-containing silane coupling agents, ureido group-containing silane coupling agents Silane coupling agents such as ring agents and sulfide group-containing silane coupling agents can be used.
When using a silane coupling agent, one type may be used alone, or two or more types may be used in combination.

Examples of amino group-containing silane coupling agents include bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane. Silane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-amino Propylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-amino-propyltrimethoxysilane and the like.
Examples of epoxy group-containing silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidyl. propyltrimethoxysilane and the like.
Examples of (meth)acryloyl group-containing silane coupling agents include γ-((meth)acryloyloxypropyl)trimethoxysilane, γ-((meth)acryloyloxypropyl)methyldimethoxysilane, γ-((meth) acryloyloxypropyl)methyldiethoxysilane and the like.
Mercapto group-containing silane coupling agents include, for example, 3-mercaptopropyltrimethoxysilane.
Vinyl group-containing silane coupling agents include, for example, vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane and the like.
Ureido group-containing silane coupling agents include, for example, 3-ureidopropyltriethoxysilane.
Examples of sulfide group-containing silane coupling agents include bis(3-(triethoxysilyl)propyl)disulfide and bis(3-(triethoxysilyl)propyl)tetrasulfide.
Acid anhydride-containing silane coupling agents include, for example, 3-trimethoxysilylpropylsuccinic anhydride, 3-triethoxysilylpropylsuccinic anhydride, and 3-dimethylmethoxysilylpropylsuccinic anhydride.

Examples of adhesion aids include not only silane coupling agents but also titanium coupling agents and zirconium coupling agents.

When an adhesion aid is used, it may be used alone, or two or more adhesion aids may be used in combination.
When an adhesion aid is used, its content is preferably 0.3 to 15 parts by mass, more preferably 0.4 to 12 parts by mass, and still more preferably 0.5 parts by mass, relative to 100 parts by mass of the phenolic resin (A). ~10 parts by mass.

(Surfactant)
The negative photosensitive resin composition of this embodiment can contain a surfactant. By including a surfactant, the wettability during coating can be improved, and a uniform resin film and cured film can be obtained. Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, alkyl-based surfactants, and acrylic surfactants.

The surfactant preferably contains a surfactant containing at least one of a fluorine atom and a silicon atom. This contributes to obtaining a uniform resin film (improvement of coatability), improvement of developability, and improvement of adhesion strength. Such a surfactant is preferably, for example, a nonionic surfactant containing at least one of a fluorine atom and a silicon atom. Examples of commercial products that can be used as surfactants include F-251, F-253, F-281, F-430, F-477, F-551 of the "Megafac" series manufactured by DIC Corporation, F-552, F-553, F-554, F-555, F-556, F-557, F-558, F-559, F-560, F-561, F-562, F-563, F- 565, F-568, F-569, F-570, F-572, F-574, F-575, F-576, R-40, R-40-LM, R-41, R-94, etc. Fluorine-containing oligomer structure surfactants, fluorine-containing nonionic surfactants such as Phthagent 250 and Phthagent 251 manufactured by Neos Co., Ltd., SILFOAM (registered trademark) series manufactured by Wacker Chemie (for example, SD 100 TS , SD 670, SD 850, SD 860, SD 882).

When the negative photosensitive resin composition contains a surfactant, the photosensitive resin composition can contain one or more surfactants.
When the photosensitive resin composition contains a surfactant, the amount thereof is, for example, 0.001 to 1 part by mass, preferably 0.005 to 0.5 parts by mass with respect to 100 parts by mass of the phenolic resin (A). .

(solvent)
The negative photosensitive resin composition of this embodiment preferably contains a solvent. As a result, the photosensitive resin film can be easily formed on the stepped substrate by a coating method. When the negative photosensitive resin composition of the present embodiment contains a solvent, the negative photosensitive resin composition of the present embodiment is in the form of varnish, for example.
A solvent usually contains an organic solvent. The organic solvent is not particularly limited as long as it can dissolve or disperse each component described above and does not substantially chemically react with each component.

Examples of organic solvents include acetone, methyl ethyl ketone, toluene, propylene glycol methyl ethyl ether, propylene glycol dimethyl ether, propylene glycol 1-monomethyl ether 2-acetate, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, benzyl alcohol, propylene carbonate, ethylene glycol diacetate, propylene glycol diacetate, propylene glycol monomethyl ether acetate, dipropylene glycol methyl-n-propyl ether, butyl acetate, γ-butyrolactone and the like. These may be used singly or in combination.

When a solvent is used, it is used so that the concentration of nonvolatile components in the negative photosensitive resin composition is preferably 30 to 75% by mass, more preferably 35 to 70% by mass. By setting it as this range, each component can fully be melt|dissolved or dispersed. In addition, good coatability can be ensured, which in turn leads to improvement in flatness during spin coating. Furthermore, the viscosity of the negative photosensitive resin composition can be appropriately controlled by adjusting the content of the non-volatile component.

(Other ingredients)
In addition to the above components, the negative photosensitive resin composition of the present embodiment may contain components other than the above components, if necessary. Examples of such components include antioxidants, fillers such as silica, sensitizers, film-forming agents, and the like.

(Characteristics of negative photosensitive resin composition)
The negative photosensitive resin composition of the present embodiment has a storage elastic modulus of 2500 Pa or less at 250° C., but by satisfying other characteristics, performance such as reliability can be further improved.

The storage elastic modulus at 100° C. of the cured product of the negative photosensitive resin composition of the present embodiment in dynamic viscoelasticity measurement under the above [conditions] is preferably 2500 MPa or more, more preferably 2500 mPa or more and 3000 MPa or less. , more preferably 3000 mPa or more and 2000 MPa or less.

The value at the peak temperature of the loss tangent (tan δ) of the cured product of the negative photosensitive resin composition of the present embodiment in dynamic viscoelasticity measurement under the above [conditions] is preferably 0.01 to 0.01. 8 or less, more preferably 0.1 or more and 0.6 or less.

The glass transition temperature (Tg) of the cured product of the negative slow-release resin composition of the present embodiment is preferably 180°C or higher, more preferably 200°C or higher. The glass transition temperature of the cured product of the negative photosensitive resin composition is preferably 260° C. or lower, more preferably 240° C. or lower.

The cured product of the negative photosensitive resin composition of the present embodiment preferably has a tensile elongation at break of 40% or more when stretched at a tensile speed of 200 mm/min according to JIS K7127, and more preferably, It is 40% or more and 200% or less, and more preferably 50% or more and 150% or less.

[Cured resin film]
A resin film is obtained by curing the photosensitive resin composition in the present embodiment. Moreover, the resin film in this embodiment is a dried film or a cured film of a photosensitive resin composition. That is, the resin film is formed by drying or curing a photosensitive resin composition, preferably by effecting the photosensitive resin composition.
This resin film is used, for example, to form a resin film for electronic devices such as a permanent film and a resist. Among these, from the viewpoint of obtaining a resin film at a low temperature, the viewpoint of having excellent workability, and the viewpoint of obtaining a resin film having excellent reliability, it is preferably used for applications using a permanent film.
According to the present embodiment, for example, for a resin film obtained using a photosensitive resin composition, a film that is excellent in workability or reliability, which is required for making a resin film useful for producing an electronic device or the like It is also possible to obtain

The permanent film is composed of a resin film obtained by pre-baking, exposing and developing a photosensitive resin composition, patterning it into a desired shape, and post-baking it to cure it. Permanent films can be used as protective films for electronic devices such as buffer coat films, interlayer films such as insulating films for rewiring, and dam materials.

The resist is applied, for example, to the object to be masked by the resist by a method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., to form a negative photosensitive resin composition. It is composed of a resin film obtained by removing the solvent from the resin composition.

FIG. 1 is a cross-sectional view showing a configuration example of an electronic device having a resin film according to this embodiment.
The electronic device 100 shown in FIG. 1 can be an electronic device including the resin film. Specifically, one or more of the group consisting of the passivation film 32, the insulating layer 42, and the insulating layer 44 in the electronic device 100 can be made of a resin film. Here, the resin film is preferably the permanent film described above.

Electronic device 100 is, for example, a semiconductor chip. In this case, for example, a semiconductor package is obtained by mounting the electronic device 100 on the wiring substrate via the bumps 52 . The electronic device 100 includes a semiconductor substrate provided with semiconductor elements such as transistors, and a multilayer wiring layer (not shown) provided on the semiconductor substrate. An interlayer insulating film 30 and a top layer wiring 34 provided on the interlayer insulating film 30 are provided in the uppermost layer of the multilayer wiring layers. The uppermost layer wiring 34 is made of aluminum Al, for example. A passivation film 32 is provided on the interlayer insulating film 30 and the uppermost layer wiring 34 . A portion of the passivation film 32 is provided with an opening through which the uppermost layer wiring 34 is exposed.

A rewiring layer 40 is provided on the passivation film 32 . The rewiring layer 40 includes an insulating layer 42 provided on the passivation film 32, a rewiring 46 provided on the insulating layer 42, an insulating layer 44 provided on the insulating layer 42 and the rewiring 46, have An opening connected to the uppermost layer wiring 34 is formed in the insulating layer 42 . The rewiring 46 is formed on the insulating layer 42 and in openings provided in the insulating layer 42 and connected to the uppermost layer wiring 34 . The insulating layer 44 is provided with an opening connected to the rewiring 46 .

A bump 52 is formed in the opening provided in the insulating layer 44 via a UBM (Under Bump Metallurgy) layer 50, for example. The electronic device 100 is connected to a wiring substrate or the like via bumps 52, for example.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above can also be adopted.

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited to these.

(Examples 1 to 7, Comparative Example 1)
A photosensitive resin composition was prepared according to the formulation shown in Table 1. Specifically, first, each component blended according to Table 1 was stirred and mixed under a nitrogen atmosphere, and filtered through a polyethylene filter having a pore size of 0.2 μm to obtain a varnish-like photosensitive resin composition. . Details of each component listed in Table 1 are shown below.

((A) phenolic resin)
・ Phenolic resin a1: biphenyl type phenolic resin, manufactured by Sumitomo Bakelite Co., Ltd., PR-X18121
(resin)
- Cyclic olefin polymer: Cyclic olefin polymer, manufactured by Sumitomo Bakelite Co., Ltd., R200309-2
((B) cross-linking agent)
· Cross-linking agent b1: 1,3,4,6-tetrakis (methoxymethyl) glycoluril, Daito Chemix Co., Ltd., CROLIN-318
· Crosslinking agent b2: 1,3,4,6-tetrakis (butoxymethyl) glycoluril, manufactured by Sanwa Chemical Co., Ltd., Nikalac MX-279
・Crosslinking agent b3: 1,3-bis(methoxymethyl)-4,5-dimethoxy-2-imidazolinone, manufactured by Sanwa Chemical Co., Ltd., Nikalac MX-280
· Crosslinking agent b4: phenoxy-type epoxy resin, manufactured by Mitsubishi Chemical Corporation, YX-7105
· Crosslinking agent b5: epoxy resin (bisphenol A type phenoxy), manufactured by Mitsubishi Chemical Corporation, JER-1256
· Crosslinking agent b6: bisphenol A type epoxy resin, manufactured by Osaka Soda Co., Ltd., LX-01
· Cross-linking agent b7: phenol aralkyl type resin, manufactured by Nippon Kayaku Co., Ltd., KAYAHARD GPH-103
· Cross-linking agent b8: dipentaerythritol polyacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., A-DPH
((C) Photosensitizer)
- Photosensitive agent 1 (photoacid generator): triarylsulfonium salt, San-Apro Co., Ltd., CPI-210S
Photosensitizer 2 (photoradical generator): 1.2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(o-benzoyloxime), BASF Japan Ltd., Irgacure OXE01
(adherence aid)
Adhesion aid 1: Trimethoxysilylpropyl succinic anhydride, manufactured by Shin-Etsu Chemical Co., Ltd., X-12-967C
Adhesion aid 2: 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403E

(Surfactant)
-Surfactant 1: fluorine-based surfactant, manufactured by 3M Japan, FC4430
・Surfactant 2: fluorine-containing group-hydrophilic group-lipophilic group-containing oligomer, manufactured by DIC, Megafac F556
(solvent)
・ Solvent 1: γ-butyrolactone, manufactured by Sanwa Yuka Kogyo Co., Ltd.

The following physical properties were measured for the obtained resin composition.
(1. Dynamic viscoelasticity measurement of cured film (measurement of storage elastic modulus at 250°C/100°C))
(Preparation of test piece)
The photosensitive resin composition was spin-coated on an 8-inch silicon wafer so that the film thickness after drying was 10 μm, followed by heating at 120° C. for 3 minutes to obtain a coating film.
The coating film thus obtained was exposed to light of 1000 mJ/cm 2 with a high-pressure mercury lamp. Thereafter, post-exposure baking was performed at 120° C. for 3 minutes, followed by immersion in tetramethylammonium hydroxide for 60 seconds. Furthermore, after that, it was cured by heating at 180° C. for 120 minutes in a nitrogen atmosphere. A cured film of the photosensitive resin composition was thus obtained.
The obtained cured product was cut with a dicing saw so as to have a width of 5 mm together with the silicon wafer. The cured film was peeled off from the wafer by immersing the cut piece in a 2 mass % hydrofluoric acid aqueous solution.
The peeled cured film was dried at 60° C. for 10 hours to obtain a test piece (30 mm×5 mm×10 μm thick).

(Measurement of storage modulus)
The resulting test piece is heated from 30°C to 300°C under the conditions of a nitrogen atmosphere, a frequency of 1 Hz, a tensile mode, and a heating rate of 5°C/min using a dynamic viscoelasticity measuring device (TA, Q800). and the storage modulus against temperature was measured. The storage modulus [MPa] at 100°C and 250°C was read from the obtained storage modulus (E') curve.

(2. Measurement of tensile elongation)
A test piece was prepared in the same manner as in (Preparation of test piece) in (1. Dynamic viscoelasticity measurement of cured film). The test piece was subjected to a tensile test using a tensile tester (Tensilon RTC-1210A, manufactured by Orientec Co., Ltd.) in an atmosphere of 23° C. in accordance with JIS K 7161 to measure the tensile elongation of the test piece. The stretching speed in the tensile test was 5 mm/min. The unit of tensile elongation is %.

(3. Measurement of glass transition temperature of cured film)
A test piece was prepared in the same manner as in (Preparation of test piece) in (1. Dynamic viscoelasticity measurement of cured film). The test piece was heated to 300° C. at a heating rate of 10° C./min using a thermomechanical analyzer (manufactured by Seiko Instruments Inc., TMA/SS6000). Thereby, the coefficient of thermal expansion of the obtained test piece was measured.
Next, the glass transition temperature Tg (unit: °C) of the cured product was calculated from the inflection point of the temperature-thermal expansion coefficient graph in the obtained measurement results. A higher Tg of the cured film means that the cured film is more stable against heat.

(4. Measurement of loss tangent (tan δ))
A test piece was prepared in the same manner as in (Preparation of test piece) in (1. Dynamic viscoelasticity measurement of cured film). The test piece was heated from 30°C to 300°C at a temperature increase rate of 10°C/min, then cooled from 300°C to 200°C at a temperature decrease rate of 10°C/min, and then heated to 200°C. Using a dynamic viscoelasticity measuring device (“DMS6100” manufactured by Seiko Instruments Inc.), the mechanical loss tangent tan δ was measured at a chuck distance of 8 mm, a frequency of 10 Hz, and a tensile mode. A larger value of tan δ indicates better flexibility.

(Low temperature curability (curing temperature))
The photosensitive resin composition obtained above was spin-coated on an 8-inch silicon wafer so that the film thickness after drying was 10 μm, and an inert oven (manufactured by Koyo Thermo Systems Co., Ltd., product number CLH-21CD-(V) -S) in a nitrogen atmosphere, and cured by heat treatment according to the following temperature setting and internal temperature measurement. Curing temperatures are shown in Table 1.
・ Curing at 180°C: Normal temperature (30°C) → Heat up to 180°C over 30 minutes → Maintain at 180°C for 2 hours → Cool down to normal temperature over 30 minutes ・ Curing at 200°C: Normal temperature (30°C) → Take 34 minutes Raise the temperature to 200°C → Maintain at 200°C for 2 hours → Lower the temperature to room temperature over 34 minutes

The resin compositions of Examples were excellent in low-temperature curability.

30 Interlayer insulating film 32 Passivation film 34 Top layer wiring 40 Rewiring layers 42, 44 Insulating layer 46 Rewiring 50 UBM layer 52 Bump 100 Electronic device

Claims (11)

A negative photosensitive resin composition used in a rewiring layer of a semiconductor device,
The negative photosensitive resin composition is
(A) a phenolic resin,
(B) a cross-linking agent, and (C) a photosensitizer,
The phenolic resin (A) includes a biphenyl-type phenolic resin,
The cross-linking agent (B) includes a bifunctional or more functional urea resin cross-linking agent and a bi- or more functional epoxy resin cross-linking agent,
A negative photosensitive resin composition having a storage elastic modulus at 250° C. measured by dynamic viscoelasticity measurement (DMA) of 2500 MPa or less when the negative photosensitive resin composition is cured. The negative photosensitive resin composition according to claim 1,
A negative photosensitive resin composition, wherein the storage elastic modulus at 100° C. measured by DMA (dynamic viscoelasticity measurement) when the negative photosensitive resin composition is cured is 2500 MPa or more. The negative photosensitive resin composition according to claim 1 or 2,
When the negative photosensitive resin composition is used as a cured product, the value at the peak temperature of the loss tangent (tan δ) obtained by dynamic viscoelasticity measurement (DMA) is 0.01 or more and 0.8 or less. Negative photosensitive resin composition. The negative photosensitive resin composition according to any one of claims 1 to 3,
A negative photosensitive resin composition having a glass transition temperature (Tg) of 180° C. or higher as measured by dynamic viscoelasticity measurement (DMA) when the negative photosensitive resin composition is cured. The negative photosensitive resin composition according to any one of claims 1 to 4,
A negative photosensitive resin composition having a tensile elongation at break of 40% or more when stretched at a tensile speed of 200 mm/min according to JIS K7127 when the negative photosensitive resin composition is cured. thing. The negative photosensitive resin composition according to any one of claims 1 to 5, wherein the bifunctional or higher functional urea resin-based cross-linking agent comprises an alkoxymethylated glycoluril compound. 7. The negative photosensitive resin composition according to any one of claims 1 to 6, wherein said bifunctional or higher epoxy resin-based cross-linking agent is a phenoxy-type epoxy resin. The negative photosensitive resin composition according to any one of claims 1 to 7, wherein the biphenyl type phenol resin has a weight average molecular weight of 2000 or more and 50000 or less. further comprising an acid generator,
The negative photosensitive resin composition according to any one of claims 1 to 8, wherein the acid generator contains a sulfonium compound or a salt thereof. A cured film obtained by curing the negative photosensitive resin composition according to any one of claims 1 to 9. a semiconductor element;
and a rewiring layer provided on the surface of the semiconductor element,
A semiconductor device, wherein the insulating layer in the rewiring layer is composed of the cured film according to claim 10 .

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