JP2023073661A - Photosensitive resin composition, cured film and semiconductor device - Google Patents

Abstract

To provide a negative photosensitive resin composition having low temperature curability and to provide a cured film having excellent strength obtained by curing the same.SOLUTION: There is provided a negative photosensitive resin composition used in a re-wiring layer of a semiconductor device, which comprises a phenol resin (A), a crosslinking agent (B) and a photosensitizing agent (C), wherein the phenol resin (A) includes a biphenyl-type phenol resin, the crosslinking agent (B) includes a tetrafunctional urea resin-based crosslinking agent and a bifunctional epoxy resin-based crosslinking agent and a cured product obtained by curing the negative photosensitive resin composition has a storage modulus at 250°C of 2500 MPa or less as measured by dynamic viscoelasticity measurement (DMA).SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a photosensitive resin composition, a cured film thereof, and a semiconductor device having the cured film as an insulating layer.

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 a positive 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 a resin film which is excellent in solubility in OK73 thinner while being curable at a low temperature, and therefore excellent in workability can be obtained, thereby completing the present invention.

According to the invention,
A positive photosensitive resin composition used in a rewiring layer of a semiconductor device,
(A) a phenolic resin,
(B) a cross-linking agent, and (C) a photosensitizer,
A positive photosensitive resin composition is provided in which the cross-linking agent (B) contains a bifunctional phenoxy-type epoxy resin.

Moreover, according to this invention, the cured film obtained by hardening the said positive 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 positive 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 groups having no substituents and groups having substituents. 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).

[Positive photosensitive resin composition]
The positive photosensitive resin composition of this embodiment is a resin material used for forming a rewiring layer of a semiconductor device. The positive 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) contains a bifunctional phenoxy-type epoxy resin.

The present inventor conducted studies to improve the low-temperature curability of a positive photosensitive resin composition and to improve the developability of the resulting cured film. As a result, the inventors have found that the above problems can be solved by making the positive photosensitive resin composition contain a specific component.
Each component used in the positive photosensitive resin composition of the present embodiment will be described below.

(Phenolic resin (A))
The positive photosensitive resin composition of this 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.

The weight average molecular weight of the biphenyl-type phenol resin (a1) may be, for example, 2000 or more, preferably 3000 or more, more preferably 4000 or more, and still more preferably 5000 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. .

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 positive photosensitive resin composition of the present embodiment is, when the total solid content of the positive photosensitive resin composition is 100 parts by mass, the curing at low temperature curing 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 positive 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 positive 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 novolac resins, cresol novolac resins, bisphenol novolac resins, phenol-biphenyl novolac resins, allylated novolac-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 positive 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 positive photosensitive resin composition, from the viewpoint of improving the 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 positive photosensitive resin composition is 100 parts by mass based on the total solid content of the positive 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 positive 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 positive 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 the phenolic resins used in the positive 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 positive photosensitive resin composition of the present embodiment contains an epoxy resin-based cross-linking agent (b1) as the cross-linking agent (B). The positive photosensitive resin composition of the present embodiment has excellent curability at low temperatures due to the inclusion of such a cross-linking agent.

As the bifunctional epoxy resin cross-linking agent (b1) used as a cross-linking agent in the positive 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-type epoxy 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) may contain a bifunctional or higher functional urea resin cross-linking agent (b2) in addition to the epoxy resin cross-linking agent (b1).
Examples of the bifunctional or higher functional urea resin-based cross-linking agent (b2) 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.

The cross-linking agent (B) is the bifunctional epoxy resin-based cross-linking agent (b1) and the bifunctional or higher-functional urea resin-based cross-linking agent (b1) within a range that does not impair the low-temperature curability of the positive photosensitive resin composition. In addition, other cross-linking agents (b3) may be included. 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 novolac resin type epoxy resin; N, N'-1 , 3-phenylenedimaleimide, N,N'-methylenedimaleimide and other maleimide compounds.

The content of the bifunctional epoxy resin-based cross-linking agent (b1) is preferably 0.1 when the total solid content of the positive photosensitive resin composition is 100 parts by mass, from the viewpoint of improving toughness during low-temperature curing. It is at least 1 part by mass, more preferably at least 1 part by mass, and still more preferably at least 10 parts by mass.
In addition, from the viewpoint of maintaining the thermomechanical properties during low-temperature curing, the content of the bifunctional epoxy resin-based cross-linking agent (b1) in the positive photosensitive resin composition is the total solid content of the photosensitive resin composition. Based on 100 parts by mass, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less.

When a bifunctional or higher urea resin-based cross-linking agent (b2) is used, its content is, when the total solid content of the positive photosensitive resin composition is 100 parts by mass, from the viewpoint of improving toughness during low-temperature curing. , preferably 80 parts by mass or more, more preferably 85 parts by mass or more, and still more preferably 90 parts by mass or more.
Further, from the viewpoint of maintaining thermomechanical properties during low-temperature curing, the content of the bifunctional or higher urea resin-based cross-linking agent (b2) in the positive photosensitive resin composition is the total solid content of the photosensitive resin composition. Based on 100 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 cross-linking agent (B) in the positive photosensitive resin composition of the present embodiment is, when the total solid content of the positive photosensitive resin composition is 100 parts by mass, the improvement in 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 positive photosensitive resin composition is 100 parts by mass based on the total solid content of the positive 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 bifunctional epoxy resin-based cross-linking agent (b1), and optionally a bifunctional or higher urea resin-based cross-linking agent (b2), and optionally It consists of other cross-linking agents (b3).

(Photosensitizer (C))
The positive 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 chain or branched hydrocarbon group or an optionally substituted benzyl group, more preferably a benzyl group, from the viewpoint of improving reactivity at low temperatures. 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 positive photosensitive resin composition contains a photosensitive agent (C), the content thereof improves the curability at low temperatures when the total solid content of the positive 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.
In addition, from the viewpoint of suppressing a decrease in reliability, the content of the photosensitive agent (C) in the positive 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 positive 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 positive 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 adhesive 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 positive 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 positive 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 positive photosensitive resin composition of this embodiment contains a solvent, the positive photosensitive resin composition of this embodiment is, for example, in the form of varnish.
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 non-volatile components in the positive 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 positive 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 positive 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 positive photosensitive resin composition)
The positive photosensitive resin composition of the present embodiment contains the above components, so that the tensile elongation of the cured film of the positive photosensitive resin composition measured under the following condition 1 is 5% or more and 200 % or less.
(Condition 1)
(i) The positive photosensitive resin composition is cured at 200° C. for 180 minutes to form the cured film, and a sample of 6.5 mm×20 mm×10 μm thick is prepared from the cured film.
(ii) Based on JIS K7161, a tensile test is performed on the sample under conditions of 23° C. and a test speed of 5 mm/min to determine the tensile elongation.
From the viewpoint of suppressing brittle fracture, the lower limit of the tensile elongation of the cured film of the positive photosensitive resin composition of the present embodiment is 5% or more, preferably 6% or more, more preferably It is 7% or more, and more preferably 8% or more. From the viewpoint of obtaining a cured film more stably, the upper limit of the tensile elongation of the cured film is 200% or less, preferably 150% or less, more preferably 125% or less, and even more preferably. is 100% or less.

The positive photosensitive resin composition of the present embodiment can have a solubility of 2 g/ml or more in OK73 thinner at 25° C. by including the above components. By having such solubility, workability in exposure and development processing is improved. Here, the solubility in OK73 thinner is measured under the following conditions.
(Conditions) A predetermined amount of the positive photosensitive resin composition and 18 g of OK73 thinner were charged into a screw tube and stirred for 30 minutes with a stirrer, and then the positive photosensitive resin composition was completely dissolved without any residue. Make sure you are

In the present embodiment, the glass transition temperature (Tg) of the cured product of the positive photosensitive resin composition is preferably 150° C. or higher, more preferably 200° C. or higher, from the viewpoint of improving heat resistance.
Moreover, from the viewpoint of suppressing deterioration of brittleness, the glass transition temperature of the cured product of the positive photosensitive resin composition is preferably 260° C. or lower, more preferably 240° C. or lower, and still more preferably 230° C. or lower.

Here, the Tg of the cured product of the positive photosensitive resin composition is determined by a thermomechanical analyzer (TMA) for a predetermined test piece (width 3 mm × length 10 mm × thickness 0.005 to 0.015 mm). is calculated from the results of measurement under the conditions of a starting temperature of 30° C., a measurement temperature range of 30 to 440° C., and a heating rate of 10° C./min.

[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: phenol aralkyl type resin, manufactured by Nippon Kayaku Co., Ltd., KAYAHARD GPH-103
・ Phenolic resin a2: Biphenyl type phenolic resin, manufactured by Sumitomo Bakelite Co., Ltd., PR-X18121
(Crosslinking agent (B))
(Epoxy resin-based cross-linking agent (b1))
· Crosslinking agent b1-1: phenoxy-type epoxy resin, manufactured by Mitsubishi Chemical Corporation, YX-7105
· Crosslinking agent b1-2: bisphenol A type epoxy resin, manufactured by Osaka Soda Co., Ltd., LX-01
· Cross-linking agent b1-3: rubber-modified epoxy resin, manufactured by DIC, TSR960
· Crosslinking agent b1-4: polypropylene glycol diglycidyl ether, manufactured by Daito Chemix, PG207GS
(Urea resin-based cross-linking agent (b2))
· Crosslinking agent b2-1: 1,3,4,6-tetrakis (methoxymethyl) glycoluril, Daito Chemix Co., Ltd., CROLIN-318
((C) Photosensitizer)
- Acid generator c1: photoacid generator, manufactured by Daito Chemix, DS-427,
・ Acid generator c2: 4-acetoxyphenyldimethylsulfonium tetrakis (pentafluorophenyl) borate, manufactured by Sanshin Chemical Industry Co., Ltd., SI-B5
・ Acid generator c3: 4-acetoxyphenylmethylbenzylsulfonium tetrakis (pentafluorophenyl) borate, manufactured by Sanshin Chemical Industry Co., Ltd., SI-B3A
(adherence aid)
・ Adhesion aid 1: 3-glycidyloxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., KBM-503P

(Surfactant)
- Surfactant 1: fluorine-based surfactant, manufactured by 3M Japan, FC4432 (10% GBL)
(solvent)
・ Solvent 1: γ-butyrolactone, manufactured by Sanwa Yuka Kogyo Co., Ltd.

The following physical properties were measured for the obtained resin composition.

(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 220°C: Normal temperature (30°C) → Heat up to 220°C over 30 minutes → Maintain at 180°C for 2 hours → Cool down to room temperature over 30 minutes

(Solubility in OK73 thinner)
2 g of the photosensitive resin composition and 18 g of OK73 thinner were placed in a screw tube and stirred for 30 minutes with a stirrer. After that, the resulting solution was visually observed and evaluated according to the following criteria.
◯: There was no residue of the photosensitive resin composition, and it was all dissolved.
Δ: The solid content of the photosensitive resin composition was visually confirmed.
(Growth rate)
The photosensitive resin composition obtained in each example was cured at 200° C. for 180 minutes to form a cured film. A sample having a thickness of 6.5 mm×20 mm×10 μm was prepared from the obtained cured film.
A tensile test of the sample was performed according to JIS K7161 using a tensile tester (Tensilon RTA-100) manufactured by Orientec under the conditions of 23° C. and a test speed of 5 mm/min. One sample was measured eight times, and the average value ("ave." in Table 1) was taken as the tensile elongation rate (%). Table 1 shows the results.

(Tg, coefficient of linear expansion (CTE)))
A cured film of the photosensitive resin composition obtained in each example was prepared at 200° C. for 180 minutes, and a test piece having a width of 3 mm×length of 10 mm×thickness of 10 mm was obtained from the obtained cured film.
Using a thermomechanical analyzer (TMA, manufactured by Seiko Instruments Inc., SS6000) for the test piece of each example, the starting temperature is 30 ° C., the measurement temperature range is 30 to 440 ° C., and the heating rate is 10 ° C./min. From the measurement results, Tg (°C) and linear expansion coefficient (ppm/°C) in the temperature range of 50 to 100°C were obtained. Table 1 shows the results.

(swelling)
Each of the photosensitive resin compositions obtained above was applied onto an 8-inch silicon wafer using a spin coater, and then prebaked on a hot plate at 120° C. for 3 minutes to obtain a coating film having a thickness of about 7.5 μm. rice field. The coating film was heated in an oven at 200° C. for 60 minutes while maintaining the oxygen concentration at 1000 ppm or less to obtain a cured film of the resin composition. The cured film was immersed in a 30 wt % ammonia solution at 50° C. for 10 minutes, then thoroughly washed with pure water and air-dried, and the film thickness after treatment was measured. The film thickness change rate between the film thickness after the treatment and the film thickness before the treatment was calculated from the following formula and used as the swelling rate of the cured product.
Swelling rate of cured product (%) {(film thickness after immersion - film thickness before immersion) / film thickness before immersion} x 100 (%)
When the swelling rate of the cured product was 5% or less, it was evaluated as "◯", and when it exceeded 5%, it was evaluated as "X".
The swelling rate of the cured product should be as small as possible in order to reduce changes in film thickness during the semiconductor manufacturing process and to eliminate process abnormalities.

(Developability)
Each of the photosensitive resin compositions obtained above was applied onto an 8-inch silicon wafer using a spin coater, and then prebaked on a hot plate at 120° C. for 3 minutes to form a coating film having a thickness of about 9.0 μm. got This coating film is passed through a mask manufactured by Toppan Printing Co., Ltd. (test chart No. 1: a pattern with a width of 0.88 to 50 μm is drawn, and an i-line stepper (NSR-4425i manufactured by Nikon Corporation) is used. Then, irradiation was performed while changing the exposure amount.
Next, using a 2.38% tetramethylammonium hydroxide aqueous solution as a developer, the development time was adjusted so that the difference between the film thickness after prebaking and the film thickness after development was 1.0 μm, and puddle was performed twice. After dissolving and removing the exposed portion by developing, the film was rinsed with pure water for 10 seconds. Minimum exposure dose + 100 mJ/c to form a pattern of 100 μm square via holes
The line pattern resolution was evaluated on the pattern exposed with an energy of ^m2 . As for the resolution, it was confirmed whether or not there was an opening in a line pattern with an interval of 10 μm. In Table 1, "○" indicates that there is an opening, and "X" indicates that there is no opening.

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 (10)

A positive photosensitive resin composition used in a rewiring layer of a semiconductor device,
(A) a phenolic resin,
(B) a cross-linking agent, and (C) a photosensitizer,
The cross-linking agent (B) is a positive photosensitive resin composition containing a bifunctional phenoxy type epoxy resin. The positive photosensitive resin composition according to claim 1, wherein the phenol resin has a weight average molecular weight of 2000 or more and 50000 or less. 3. The positive photosensitive resin composition according to claim 1, wherein the cross-linking agent (B) further comprises a bifunctional or higher functional urea resin-based cross-linking agent. 4. The positive photosensitive resin composition according to claim 3, wherein the bifunctional or higher functional urea resin-based cross-linking agent comprises an alkoxymethylated glycoluril compound. 5. Any one of claims 1 to 4, wherein the bifunctional phenoxy type epoxy resin is in an amount of 0.1% by mass or more and 60% by mass or less with respect to the total solid content of the positive photosensitive resin composition. The positive photosensitive resin composition according to Item 1. The positive photosensitive resin composition according to any one of claims 1 to 5, wherein the photosensitive agent (C) contains a thermal acid generator. The positive according to any one of claims 1 to 6, wherein the tensile elongation of the cured film of the positive photosensitive resin composition is 5% or more and 200% or less, measured under the following condition 1. type photosensitive resin composition.
(Condition 1)
(i) The positive photosensitive resin composition is cured at 200° C. for 180 minutes to form the cured film, and a sample of 6.5 mm×20 mm×10 μm thick is prepared from the cured film.
(ii) Based on JIS K7161, a tensile test is performed on the sample under conditions of 23° C. and a test speed of 5 mm/min to determine the tensile elongation. 8. The positive photosensitive resin composition according to any one of claims 1 to 7, wherein the solubility in OK73 thinner at 25°C is 2 g/ml or more. A cured film obtained by curing the positive photosensitive resin composition according to any one of claims 1 to 8. 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 9 .

Images