JP7840247B2 - Manufacturing methods for electronic devices - Google Patents

Description

This invention relates to a photosensitive resin composition and a method for manufacturing an electronic device.

In the electrical and electronic fields, photosensitive resin compositions containing polyamide resins and/or polyimide resins are sometimes used to form cured films such as insulating layers. Therefore, photosensitive resin compositions containing polyamide resins and/or polyimide resins have been studied extensively.

As an example, Patent Document 1 describes a photosensitive composition comprising at least one fully imidized polyimide polymer having a weight-average molecular weight in the range of about 20,000 Daltons to about 70,000 Daltons; at least one solubility-switching compound; at least one photoinitiator; and at least one solvent, which can form a film exhibiting a dissolution rate of more than about 0.15 μm/second when cyclopentanone is used as a developer.

Patent documents 2 and 3, among others, also describe photosensitive resin compositions containing polyamide resins and/or polyimide resins.

International Publication No. 2016/172092 International Publication No. 2007/047384 Japanese Patent Publication No. 2018-070829

When forming a cured film in an electronic device using a photosensitive resin composition, a heat-curing treatment is typically performed. Specifically, first, the photosensitive resin composition is applied to a substrate to form a film, and then this film is patterned by exposure or development. Finally, the patterned film is heat-treated to form a cured film.
In the formation of a cured film by heating as described above, it is preferable to suppress the shrinkage of the film due to heating. In particular, there has been a growing demand in recent years for the formation of a flat cured film on a substrate with steps. However, if the film shrinks significantly, problems such as loss of film flatness may occur.

This invention was made in view of these circumstances. One of the objectives of this invention is to provide a photosensitive resin composition capable of forming a cured film with low shrinkage due to heating and good flatness.

The present inventors have completed the invention described below and solved the above-mentioned problems.

According to the present invention,
Polyimide (A) having an imide ring structure,
Polyfunctional (meth)acrylate compound (B),
Photosensitive material (C),
Solvent (J) and,
A photosensitive resin composition containing the following is provided.

Furthermore, according to the present invention,
A film formation step of forming a photosensitive resin film on a substrate using the above-mentioned photosensitive resin composition,
An exposure step of exposing the photosensitive resin film,
A developing step for developing the exposed photosensitive resin film,
A method for manufacturing an electronic device is provided, including the following.

Furthermore, according to the present invention,
An electronic device comprising a cured film of the above-described photosensitive resin composition is provided.

According to the present invention, a photosensitive resin composition is provided that exhibits minimal shrinkage upon heating and can form a cured film with good flatness.

This is a longitudinal cross-sectional view showing an example of the configuration of an electronic device. Figure 2 is a magnified view of the area enclosed by the dashed line in Figure 1. Figure 1 is a process diagram showing a method for manufacturing the electronic device shown in Figure 1. This figure illustrates a method for manufacturing the electronic device shown in Figure 1. This figure illustrates a method for manufacturing the electronic device shown in Figure 1. This figure illustrates a method for manufacturing the electronic device shown in Figure 1.

Embodiments of the present invention will be described in detail below with reference to the drawings.
In all drawings, similar components are denoted by the same reference numerals, and explanations are omitted where appropriate.
To avoid complexity, (i) if there are multiple identical components in the same drawing, only one will be assigned a reference numeral, and none of them will be assigned a reference numeral; and (ii) especially in Figure 2 and later, components similar to those in Figure 1 will not be assigned a reference numeral again.
All drawings are for illustrative purposes only. The shapes and dimensional ratios of the components shown in the drawings do not necessarily correspond to actual items.

In this specification, the term "abbreviated" means, unless otherwise explicitly stated, a range that takes into account manufacturing tolerances, assembly variations, etc.
In this specification, the notation "X to Y" in descriptions of numerical ranges means "X or greater and Y or less" unless otherwise specified. For example, "1 to 5 mass%" means "1 mass% or greater and 5 mass% or less".

In this specification, when a group (atomic group) is not specified as substituted or unsubstituted, it includes both unsubstituted and substituted groups. For example, "alkyl group" includes not only unsubstituted alkyl groups but also substituted alkyl groups.
In this specification, the term "(meth)acrylic" refers to a concept that encompasses both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate."
In this specification, unless otherwise specified, the term "organic group" refers to an atomic group obtained by removing one or more hydrogen atoms from an organic compound. For example, "monovalent organic group" refers to an atomic group obtained by removing one hydrogen atom from any organic compound.
In this specification, the term "electronic device" is used to encompass elements, devices, and final products to which electronic engineering technology is applied, such as semiconductor chips, semiconductor elements, printed circuit boards, electrical circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, and chemical batteries.

<Photosensitive resin composition>
The photosensitive resin composition of this embodiment comprises a polyimide (A) having an imide ring structure, a polyfunctional (meth)acrylate compound (B), a photosensitive agent (C), and a solvent (J).

Many conventional polyamide/polyimide-based photosensitive resin compositions contain polyamide but not polyimide before use (before the formation of a cured film). In other words, conventionally, a film was often formed on a substrate using a photosensitive resin composition containing polyamide, and then the film was typically heated to cyclize the polyamide and convert it to polyimide.
However, in this case, the film may shrink due to ring-closing reactions and the resulting dehydration, making it difficult to obtain a cured film with good flatness.

On the other hand, the photosensitive resin composition of this embodiment contains a polyimide (A) that already has an imide ring structure before use (before the formation of the cured film). Furthermore, in this embodiment, a polymerization reaction of a polyfunctional (meth)acrylate compound (B) is employed as the curing mechanism (this polymerization reaction, in principle, does not involve dehydration). Due to these factors, by forming a cured film using the photosensitive resin composition of this embodiment, it is possible to form a cured film with low shrinkage due to heating and good flatness. In particular, it is possible to form a cured film with good flatness even on substrates with steps.

Furthermore, by using the photosensitive resin composition of this embodiment, it is easy to form a cured film with good heat resistance and good mechanical properties (e.g., tensile elongation).
Cured films in electronic devices often require high heat resistance and good mechanical properties. However, conventionally, designing resins to be rigid in order to increase heat resistance sometimes resulted in a loss of flexibility and a decrease in mechanical properties.
Although the details are unclear, in the photosensitive resin composition of this embodiment, it is thought that the polyfunctional (meth)acrylate compound (B) becomes intricately entangled with the polyimide (A) having an imide ring structure during curing (polymerization), resulting in the formation of a cured film different from conventional cured films. This "entangled structure between the cyclic polyimide and the polyfunctional (meth)acrylate" is thought to be related to the good heat resistance and good mechanical properties.

Based on the above considerations, the photosensitive resin composition of this embodiment is preferably used for forming insulating layers in electronic devices.

The following will continue the explanation of the components that can be included in the photosensitive resin composition of this embodiment, as well as the properties and physical characteristics of the photosensitive resin composition of this embodiment.

(Polyimide (A) having an imide ring structure)
The photosensitive resin composition of this embodiment contains polyimide (A) having an imide ring structure. Hereinafter, polyimide (A) having an imide ring structure will also be simply referred to as "polyimide (A)".
As already mentioned, the photosensitive resin composition of this embodiment tends to undergo less curing (heating) because it uses a polyimide that has an imide ring structure before curing.

When the number of moles of imide groups contained in polyimide (A) is denoted as IM and the number of moles of amide groups contained in polyimide (A) is denoted as AM, the imidization rate, expressed as {IM/(IM+AM)} × 100 (%), is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. In short, it is preferable that polyimide (A) is a resin that has few or no ring-open amide structures and many ring-closed imide structures. By using such a polyimide, shrinkage due to heating can be further suppressed, and a cured film with better flatness can be formed.
The imidation rate can be determined, for example, from the area of the peak corresponding to the amide group or the peak corresponding to the imide group in the NMR spectrum. Alternatively, the imidation rate can be determined from the area of the peak corresponding to the amide group or the peak corresponding to the imide group in the infrared absorption spectrum.

The polyimide (A) preferably contains a polyimide with fluorine atoms. Our findings indicate that polyimides containing fluorine atoms tend to have better organic solvent solubility than polyimides without fluorine atoms. Therefore, using a polyimide containing fluorine atoms makes it easier to create a varnish-like property in the photosensitive resin composition.
The amount (mass ratio) of fluorine atoms in polyimide containing fluorine atoms is, for example, 1 to 30% by mass, preferably 3 to 28% by mass, and more preferably 5 to 25% by mass. A sufficiently large amount of fluorine atoms in the polyimide makes it easier to obtain sufficient solubility in organic solvents. On the other hand, from the viewpoint of balancing with other properties, it is preferable that the amount of fluorine atoms is not too high.

By designing the ends of the polyimide (A) in various ways, it is possible to further improve the mechanical properties of the cured product (such as tensile elongation).

As an example, polyimide (A) preferably has a group at its terminal end that can react with an epoxy group to form a bond. Examples of such groups include acid anhydride groups, hydroxyl groups, amino groups, and carboxyl groups.

Preferably, polyimide (A) has an acid anhydride group at its terminal end. In the photosensitive resin composition of this embodiment, the acid anhydride group and the epoxy group readily bond together.
The acid anhydride group is preferably a group having a cyclic acid anhydride skeleton. Here, "cyclic structure" is preferably a five-membered ring or a six-membered ring, more preferably a five-membered ring.

Regarding the terminal structure, it is preferable that polyimide (A) does not have a maleimide structure at its terminal end.

Polyimide (A) preferably contains structural units represented by the following general formula (a).

In general formula (a),
X is a divalent organic group,
Y is a tetravalent organic group,
At least one of X and Y is a fluorine atom-containing group.

The divalent organic group of X and/or the tetravalent organic group of Y preferably contain an aromatic ring structure, and more preferably a benzene ring structure. This tends to further enhance heat resistance.
From the viewpoint of organic solvent solubility, it is preferable that both X and Y are fluorine atom-containing groups.
The divalent organic group of X and/or the tetravalent organic group of Y preferably have a structure in which 2 to 6 benzene rings are linked by single bonds or divalent linking groups. Examples of divalent linking groups here include alkylene groups, alkylene fluorides, and ether groups. The alkylene groups and alkylene fluorides may be linear or branched.
The number of carbon atoms in the divalent organic group of X is, for example, 6 to 30.
The number of carbon atoms in the tetravalent organic group of Y is, for example, 6 to 20.
The two imide rings in general formula (a) are preferably five-membered rings.

Polyimide (A) is more preferably composed of structural units represented by the following general formula (aa).

In the general formula (aa),
Y' represents a single bond or an alkylene group.
X is synonymous with X in general formula (a).
The alkylene group of Y' may be linear or branched. Preferably, some or all of the hydrogen atoms of the alkylene group of Y' are substituted with fluorine atoms. The number of carbon atoms in the alkylene group of Y' is, for example, 1 to 6, preferably 1 to 4, and more preferably 1 to 3.

Polyimide (A) can typically be obtained by (i) first reacting (condensation polymerization) a diamine with an acidic dianhydride to synthesize a polyamide, (ii) then imidizing (ring-closing reaction) the polyamide, and (iii) introducing desired functional groups to the polymer ends as needed. Specific reaction conditions can be found in the examples provided later and in the aforementioned Patent Document 1.

In the final polyimide (A), the diamine is incorporated into the polymer as a divalent organic group X in general formula (a). The acidic dianhydride is incorporated into the polymer as a tetravalent organic group Y in general formula (a).
In the synthesis of polyimide (A), one or more diamines may be used, and one or more acidic dianhydrides may also be used.

Examples of diamines used as raw materials include 3,4'-diaminodiphenyl ether (3,4'-ODA), 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB), 3,3',5,5'-tetramethylbenzidine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,3'-diaminodiphenyl sulfone, 3,3'-dimethylbenzidine, 3,3'-bis(trifluoromethyl)benzidine, and 2,2'-bis(p-aminophenyl)hexa Fluoropropane, bis(trifluoromethoxy)benzidine (TFMOB), 2,2'-bis(pentafluoroethoxy)benzidine (TFEOB), 2,2'-trifluoromethyl-4,4'-oxydianiline (OBABTF), 2-phenyl-2-trifluoromethyl-bis(p-aminophenyl)methane, 2-phenyl-2-trifluoromethyl-bis(m-aminophenyl)methane, 2,2'-bis(2-heptafluoroisopropoxy-tetrafluoroethoxy) ) Benzidine (DFPOB), 2,2-bis(m-aminophenyl)hexafluoropropane (6-FmDA), 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 3,6-bis(trifluoromethyl)-1,4-diaminobenzene (2TFMPDA), 1-(3,5-diaminophenyl)-2,2-bis(trifluoromethyl)-3,3,4,4,5,5,5-heptafluoropentane, 3,5-diaminobenzotrifluoride (3,5-DABT F) 3,5-diamino-5-(pentafluoroethyl)benzene, 3,5-diamino-5-(heptafluoropropyl)benzene, 2,2'-dimethylbenzidine (DMBZ), 2,2',6,6'-tetramethylbenzidine (TMBZ), 3,6-diamino-9,9-bis(trifluoromethyl)xanthene (6FCDAM), 3,6-diamino-9-trifluoromethyl-9-phenylxanthene (3FCDAM), 3,6-diamino-9,9-diphenylxanthene

Examples of acid dianhydrides used as raw materials include pyromellitic anhydride (PMDA), diphenyl ether-3,3',4,4'-tetracarboxylic dianhydride (ODPA), benzophenone-3,3',4,4'-tetracarboxylic dianhydride (BTDA), biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA), diphenyl sulfone-3,3',4,4'-tetracarboxylic dianhydride (DSDA), diphenylmethane-3,3',4,4'-tetracarboxylic dianhydride, 2,2-bis(3,4-phthalic anhydride)propane, and 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane (6FDA). Of course, the usable acid dianhydrides are not limited to these. One or more acid dianhydrides can be used.

The ratio of diamine to acid dianhydride is basically 1:1 molarly. However, one may be used in excess to obtain the desired terminal structure. Specifically, using an excess of diamine makes it easier for the terminals (both ends) of polyimide (A) to become amino groups. On the other hand, using an excess of acid dianhydride makes it easier for the terminals (both ends) of polyimide (A) to become acid anhydride groups. As mentioned above, in this embodiment, it is preferable for polyimide (A) to have acid anhydride groups at its terminals. Therefore, in this embodiment, it is preferable to use an excess of acid dianhydride when synthesizing polyimide (A).

The terminal amino groups and/or acid anhydride groups of the polyimide obtained by condensation polymerization may be reacted with some reagent to make the polyimide terminals possess desired functional groups.

The weight-average molecular weight of polyimide (A) is, for example, 5,000 to 100,000, preferably 7,000 to 75,000, and more preferably 10,000 to 50,000. A sufficiently large weight-average molecular weight of polyimide (A) allows for sufficient heat resistance of the cured film, for example. Furthermore, a weight-average molecular weight of polyimide (A) that is not too large makes it easier to dissolve polyimide (A) in organic solvents.
The weight-average molecular weight can usually be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance.

(Polyfunctional (meth)acrylate compound (B))
The photosensitive resin composition of this embodiment contains a polyfunctional (meth)acrylate compound (B). The polyfunctional (meth)acrylate compound (B) is not particularly limited to those having two or more (meth)acryloyl groups in one molecule.

From the viewpoint of realizing the aforementioned "intertwined structure of a cyclic polyimide and a polyfunctional (meth)acrylate" and obtaining a hardened film that is strong and has good chemical resistance, it is preferable that the polyfunctional (meth)acrylate compound (B) has three or more functions. There is no particular upper limit to the number of functional groups of the polyfunctional (meth)acrylate compound (B), but considering the ease of obtaining raw materials, the upper limit is, for example, 11 functions.
As a general trend, when using polyfunctional (meth)acrylate compounds (B) with a large number of functional groups ((meth)acryloyl groups), the chemical resistance of the cured film tends to improve. On the other hand, when using polyfunctional (meth)acrylate compounds (B) with a small number of functional groups ((meth)acryloyl groups), the mechanical properties of the cured film, such as tensile elongation, tend to be good.

For example, the polyfunctional (meth)acrylate compound (B) preferably contains a (meth)acrylate compound (B1) with seven or more functions.

As an example, the polyfunctional (meth)acrylate compound (B) preferably contains a 5-6 functional (meth)acrylate compound (B2).

For example, the polyfunctional (meth)acrylate compound (B) preferably contains a tri- or tetrafunctional (meth)acrylate compound (B3).

As an example, polyfunctional (meth)acrylate compound (B) may include compounds represented by the following general formula. In the following general formula, R' is a hydrogen atom or a methyl group, n is 0 to 3, and R is a hydrogen atom or a (meth)acryloyl group.

Specific examples of polyfunctional (meth)acrylate compounds (B) include the following. Of course, polyfunctional (meth)acrylate compounds (B) are not limited to these.

Polyol polyacrylates such as ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; epoxy acrylates such as bisphenol A diglycidyl ether di(meth)acrylate and hexanediol diglycidyl ether di(meth)acrylate; and urethane(meth)acrylates obtained by the reaction of polyisocinate with hydroxyl group-containing (meth)acrylates such as hydroxyethyl(meth)acrylate.

Arronix M-400, Arronix M-460, Arronix M-402, Arronix M-510, Arronix M-520 (manufactured by Toagosei Co., Ltd.), KAYARAD T-1420, KAYARAD DPHA, KAYARAD DPCA20, KAYARAD DPCA30, KAYARAD DPCA60, KAYARAD Commercially available products such as DPCA120 (manufactured by Nippon Kayaku Co., Ltd.), Viscoat #230, Viscoat #300, Viscoat #802, Viscoat #2500, Viscoat #1000, Viscoat #1080 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), NK Ester A-BPE-10, NK Ester A-GLY-9E, NK Ester A-9550, and NK Ester A-DPH (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.).

The photosensitive resin composition may contain only one polyfunctional (meth)acrylate compound (B), or it may contain two or more polyfunctional (meth)acrylate compounds (B). In the latter case, it is preferable to use polyfunctional (meth)acrylate compounds (B) with different numbers of functional groups in combination. By using polyfunctional (meth)acrylate compounds (B) with different numbers of functional groups in combination, a more complex "intertwined structure of cyclic polyimide and polyfunctional (meth)acrylate" can be formed, which is thought to result in better heat resistance and mechanical properties.
Incidentally, some commercially available polyfunctional (meth)acrylate compounds (B) are mixtures of (meth)acrylates with different numbers of functional groups.

The amount of the polyfunctional (meth)acrylate compound (B) per 100 parts by mass of polyimide (A) is, for example, 50 to 200 parts by mass, preferably 60 to 150 parts by mass, more preferably 50 to 150 parts by mass, and even more preferably 70 to 120 parts by mass.
The amount of polyfunctional (meth)acrylate compound (B) used is not particularly limited, but by appropriately adjusting the amount used as described above, one or more of the various performance characteristics can be further improved. As mentioned above, in the photosensitive resin composition of this embodiment, it is thought that an "entangled structure of cyclic polyimide and polyfunctional (meth)acrylate" is formed upon curing. By appropriately adjusting the amount of polyfunctional (meth)acrylate compound (B) used relative to polyimide (A), the polyimide (A) and polyfunctional (meth)acrylate compound (B) become sufficiently entangled, and the amount of excess components that do not participate in the entanglement is reduced, resulting in further improved performance.

(Photosensitive material (C))
The photosensitive resin composition of this embodiment includes a photosensitive agent (C). The photosensitive agent (C) is not particularly limited, as long as it is capable of generating active species upon exposure to light and curing the photosensitive resin composition.

The photosensitive agent (C) preferably includes a photoradical generator. The photoradical generator is particularly effective in polymerizing the polyfunctional (meth)acrylate compound (B).

The photoradical generators that can be used are not particularly limited, and known ones can be used as appropriate.
For example, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl] Alkylphenone compounds such as -1-butanone; benzophenone compounds such as benzophenone, 4,4'-bis(dimethylamino)benzophenone, and 2-carboxybenzophenone; benzoin compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; thioxanthone compounds such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, and 2,4-diethylthioxanthone; 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, and 2-(4-ethoxynaphthyl)-4,6 Halomethylated triazine compounds such as -bis(trichloromethyl)-s-triazine and 2-(4-ethoxycarboquinylnaphthyl)-4,6-bis(trichloromethyl)-s-triazine; halomethylated oxadiazole compounds such as 2-trichloromethyl-5-(2'-benzofuryl)-1,3,4-oxadiazole, 2-trichloromethyl-5-[β-(2'-benzofuryl)vinyl]-1,3,4-oxadiazole, 4-oxadiazole, and 2-trichloromethyl-5-furyl-1,3,4-oxadiazole; 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2' Examples include biimidazole compounds such as -bis(2,4,6-trichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole; oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyl oxime); titanocene compounds such as bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)-phenyl)titanium; benzoic acid ester compounds such as p-dimethylaminobenzoic acid and p-diethylaminobenzoic acid; and acridine compounds such as 9-phenylacridine. Among these, oxime ester compounds are particularly preferred.

The photosensitive resin composition may contain only one type of photosensitive agent (C), or it may contain two or more types.
The amount of photosensitive agent (C) used is, for example, 1 to 30 parts by mass, preferably 5 to 20 parts by mass, per 100 parts by mass of polyfunctional (meth)acrylate compound (B).

(Thermal radical initiator (D))
The photosensitive resin composition of this embodiment preferably contains a thermal radical initiator (D). By using a thermal radical initiator (D), for example, the heat resistance of the cured film can be further enhanced, and/or the chemical resistance (resistance to organic solvents, etc.) of the cured film can be improved. This is thought to be because the polymerization reaction of the polyfunctional (meth)acrylate compound (B) is further promoted by using a thermal radical initiator (D).

The thermal radical initiator (D) preferably includes an organic peroxide. Examples of organic peroxides include octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, oxalic acid peroxide, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethyl peroxy-2-ethylhexanoate, t-hexyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, m-toluyl peroxide, benzoyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, acetyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, cumene hydroperoxide, dicumyl peroxide, t-butyl perbenzoate, parachlorobenzoyl peroxide, and cyclohexanone peroxide.

When using a thermal radical initiator (D), one thermal radical initiator (D) may be used, or two or more thermal radical initiators (D) may be used.
When a thermal radical initiator (D) is used, the amount is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the polyfunctional (meth)acrylate compound (B).

(Epoxy resin (E))
The photosensitive resin composition of this embodiment preferably includes an epoxy resin (E). Although the details are unclear, it is thought that the epoxy resin (E) reacts (forms a bond) with, for example, polyimide (A). The flexibility of the ether structure formed by the reaction likely enhances the mechanical properties (such as tensile elongation) of the cured film.

As the epoxy resin (E), any compound having one or more (preferably two or more) epoxy groups in one molecule can be used as appropriate.
Specific examples of epoxy resin (E) include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol Z type epoxy resin (4,4'-cyclohexydienebisphenol type epoxy resin), tetramethylbisphenol Bisphenol-type epoxy resins such as Nol-F type epoxy resin; phenol novolac-type epoxy resins, brominated phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, tetraphenol group ethane-type novolac-type epoxy resins, novolac-type epoxy resins having a condensed ring aromatic hydrocarbon structure, and other novolac-type epoxy resins; biphenyl-type epoxy resins; xylylene-type epoxy resins, biphenyl aralkyl-type epoxy resins, and other aralkyl-type epoxy resins; naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalene-type epoxy resins, naphthalenediol-type epoxy resins Epoxy resins, naphthalene-containing epoxy resins such as bi- to tetrafunctional epoxy naphthalene resins, binaphthyl epoxy resins, and naphthalene aralkyl epoxy resins; anthracene epoxy resins; phenoxy epoxy resins; dicyclopentadiene epoxy resins; norbornene epoxy resins; adamantane epoxy resins; fluorene epoxy resins, phosphorus-containing epoxy resins, alicyclic epoxy resins, aliphatic chain epoxy resins, bisphenol A novolac epoxy resins, bixylenol epoxy resins, trihydroxyphenylmethane epoxy resins, stilbene epoxy resins, tetra Examples include heterocyclic epoxy resins such as lapheniroleethane-type epoxy resins and triglycidyl isocyanurates; glycidylamines such as N,N,N',N'-tetraglycidylmetoxylendiamine, N,N,N',N'-tetraglycidylbisaminomethylcyclohexane, and N,N-diglycidylaniline, as well as copolymers of glycidyl (meth)acrylates with compounds having ethylenically unsaturated double bonds; epoxy resins having a butadiene structure; diglycidyl ethers of bisphenols; diglycidyl ethers of naphthalenediols; and glycidyl ethers of phenols.
Furthermore, the epoxy resins include n-butyl glycidyl ether, 2-ethoxyhexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerol polyglycidyl ether, sorbitol polyglycidyl ether, glycidyl ethers such as bisphenol A (or F) glycidyl ether, glycidyl esters such as adipic acid diglycidyl ester and o-phthalate diglycidyl ester, 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexane) carboxylate, and 3,4-epoxy-6-methylcyclohexylmethyl (3 ,4-epoxy-6-methylcyclohexane)carboxylate, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, dicyclopentanediene oxide, bis(2,3-epoxycyclopentyl) ether, and alicyclic epoxy resins such as Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085, Celoxide 8000, and Epolid GT401 from Daicel Corporation, 2,2'-(((((1-(4-(2-(4-(oxiran-2-ylmethoxy)phenyl)propan-2-yl)phenyl)ethane-1,1-diyl)bis(4,1-phenylene))bis(oxy))bis(methylene))bis(oxiran)) (for example, Techmore from Printec Corporation Other examples include aliphatic polyglycidyl ethers such as VG3101L), Epolite 100MF (manufactured by Kyoeisha Chemical Industry Co., Ltd.), and Epiol TMP (manufactured by NOF Corporation), as well as 1,1,3,3,5,5-hexamethyl-1,5-bis(3-(oxiran-2-ylmethoxy)propyl)trisiloxane (e.g., DMS-E09 (manufactured by Gellest)).

Preferably, the epoxy resin has 2 to 4 epoxy groups per molecule, and more preferably, 2 to 3 epoxy groups per molecule. By adjusting the number of functional groups in the epoxy resin, it is easy to improve, for example, the heat resistance and mechanical properties of the cured film in a balanced manner.
From another perspective, epoxy resins having an aromatic ring structure and/or an alicyclic structure are preferred. Using such epoxy resins is particularly preferable from the viewpoint of heat resistance.

When using epoxy resin (E), you may use only epoxy resin 1, or you may use epoxy resins 2 or more in combination.
When epoxy resin (E) is used, the amount is, for example, 0.5 to 30 parts by mass, preferably 1 to 20 parts by mass, and more preferably 3 to 15 parts by mass, per 100 parts by mass of polyimide (A).

(Curing catalyst (F))
The photosensitive resin composition of this embodiment preferably includes a curing catalyst (F). This curing catalyst (F) has the function of promoting the reaction of the epoxy resin (E). By using the curing catalyst (F), the reaction involving the epoxy resin (E) proceeds sufficiently, and for example, the tensile elongation of the cured film can be further improved.

Examples of curing catalysts (F) include compounds known as curing catalysts (often also called curing accelerators) for epoxy resins. For example, diazabicycloalkenes such as 1,8-diazabicyclo[5,4,0]undecene-7 and their derivatives; amine compounds such as tributylamine and benzyldimethylamine; imidazole compounds such as 2-methylimidazole; organophosphines such as triphenylphosphine and methyldiphenylphosphine; tetra-substituted phosphonium salts such as tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetrabenzoate, tetraphenylphosphonium tetranaphthoic acid borate, tetraphenylphosphonium tetranaphthoyloxyborate, tetraphenylphosphonium tetranaphthyloxyborate, and tetraphenylphosphonium 4,4'-sulfonyldiphenolate; and triphenylphosphine adducted with benzoquinone. Among these, organophosphines are particularly preferred.

When using a curing catalyst (F), its amount is, for example, 1 to 80 parts by mass, preferably 5 to 50 parts by mass, and more preferably 5 to 30 parts by mass, per 100 parts by mass of epoxy resin (E).

(Silane coupling agent (G))
The photosensitive resin composition of this embodiment preferably contains a silane coupling agent (G). By using a silane coupling agent (G), for example, the adhesion between the substrate and the cured film can be further improved.

As the silane coupling agent (G), for example, silane coupling agents such as 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, sulfide group-containing silane coupling agents, and silane coupling agents having a cyclic anhydride structure can be used.

Examples of amino group-containing silane coupling agents include bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldiethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane.
Examples of epoxy group-containing silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidylpropyltrimethoxysilane.
Examples of silane coupling agents containing a (meth)acryloyl group include γ-((meth)acryloyloxypropyl)trimethoxysilane, γ-((meth)acryloyloxypropyl)methyldimethoxysilane, and γ-((meth)acryloyloxypropyl)methyldiethoxysilane.
Examples of mercapto group-containing silane coupling agents include 3-mercaptopropyltrimethoxysilane.
Examples of vinyl group-containing silane coupling agents include vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, and vinyltrimethoxysilane.
Examples of ureido group-containing silane coupling agents include 3-ureidopropyltriethoxysilane.
Examples of sulfide group-containing silane coupling agents include bis(3-(triethoxysilyl)propyl) disulfide and bis(3-(triethoxysilyl)propyl) tetrasulfide.
Examples of silane coupling agents having a cyclic anhydride structure include 3-trimethoxysilylpropyl succinic anhydride, 3-triethoxysilylpropyl succinic anhydride, and 3-dimethylmethoxysilylpropyl succinic anhydride.

In this embodiment, a silane coupling agent having a cyclic anhydride structure is particularly preferred. Although the details are unclear, it is presumed that the cyclic anhydride structure readily reacts with the main chain, side chains, and/or terminals of polyimide (A), thereby providing a particularly good adhesion improvement effect.

When a silane coupling agent (G) is used, it may be used alone or in combination with two or more adhesion promoters.
When a silane coupling agent (G) is used, the amount used is, for example, 0.1 to 20 parts by mass, preferably 0.3 to 15 parts by mass, more preferably 0.4 to 12 parts by mass, and even more preferably 0.5 to 10 parts by mass, when the amount of polyimide (A) used is 100 parts by mass.

(Surfactant (H))
The photosensitive resin composition of this embodiment preferably contains a surfactant (H). This can further improve the coatability of the photosensitive resin composition and the flatness of the film.
Examples of surfactants (H) include fluorine-based surfactants, silicone-based surfactants, alkyl-based surfactants, and acrylic-based surfactants.
From another perspective, it is preferable that the surfactant is nonionic. The use of a nonionic surfactant is preferable, for example, in that it suppresses unintentional reactions with other components in the composition and improves the storage stability of the composition.

The surfactant (H) preferably contains a surfactant that includes at least one of a fluorine atom and a silicon atom. This contributes to obtaining a uniform resin film (improved coatability), improved developability, and improved adhesive strength. Such a surfactant is preferably a nonionic surfactant that includes at least one of a fluorine atom and a silicon atom. Examples of commercially available products that can be used as surfactant (H) include the "MegaFac" series from DIC Corporation: F-251, F-253, F-281, F-430, F-477, F-551, 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-560 Examples include fluorine-containing oligomer surfactants such as 68, F-569, F-570, F-572, F-574, F-575, F-576, R-40, R-40-LM, R-41, and R-94; fluorine-containing nonionic surfactants such as Futergent 250 and Futergent 251 manufactured by Neos Co., Ltd.; and silicone-based surfactants such as the SILFOAM® series (e.g., SD 100 TS, SD 670, SD 850, SD 860, SD 882) manufactured by Wacker Chemie.
Furthermore, FC4430 and FC4432 manufactured by 3M can also be cited as preferred surfactants.

If the photosensitive resin composition of this embodiment contains a surfactant (H), it may contain one or more surfactants.
If the photosensitive resin composition of this embodiment contains a surfactant (H), the amount is, for example, 0.001 to 1 part by mass, preferably 0.005 to 0.5 parts by mass, when the polyimide (A) content is 100 parts by mass.

(Water (I))
The photosensitive resin composition of this embodiment may contain water. The presence of water facilitates the hydrolysis reaction of the silane coupling agent (G), for example, and tends to improve the adhesion between the substrate and the cured film.

When the photosensitive resin composition of this embodiment contains water, the amount is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, and even more preferably 0.5 to 2 parts by mass, based on 100 parts by mass of the total solid content (non-volatile components) of the photosensitive resin composition.

The water content of the photosensitive resin composition can be quantified using the Karl Fischer method.

(Solvent (J) / Properties of the composition)
The photosensitive resin composition of this embodiment preferably contains a solvent (J). This allows for easy formation of a photosensitive resin film on a substrate (especially a substrate with steps) by a coating method.
The solvent (J) typically includes organic solvents. The organic solvent is not particularly limited, as long as it is capable of dissolving or dispersing each of the above-mentioned components and does not substantially react with each of the components.

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, methyl lactate, ethyl lactate, and butyl lactate. These may be used individually or in combination.

When the photosensitive resin composition of this embodiment contains a solvent (J), the photosensitive resin composition of this embodiment is typically varnish-like. More specifically, the photosensitive resin composition of this embodiment is preferably a varnish-like composition in which at least polyimide (A) and a polyfunctional (meth)acrylate compound (B) are dissolved in the solvent (J). Because the photosensitive resin composition of this embodiment is varnish-like, a uniform film can be formed by coating. Furthermore, because the polyimide (A) and the polyfunctional (meth)acrylate compound (B) are "dissolved" in the solvent (J), a homogeneous cured film can be obtained.

When solvent (J) is used, the concentration of total solids (non-volatile components) in the photosensitive resin composition is preferably 10 to 50% by mass, more preferably 20 to 45% by mass. This range allows for sufficient dissolution or dispersion of each component. It also ensures good coatability, which in turn leads to improved flatness during spin coating. Furthermore, the viscosity of the photosensitive resin composition can be appropriately controlled by adjusting the content of non-volatile components.
From another perspective, the proportion of polyimide (A) and polyfunctional (meth)acrylate compound (B) in the overall composition is preferably 20 to 50% by mass. Using a relatively large amount of polyimide (A) and polyfunctional (meth)acrylate compound (B) makes it easier to form a film of appropriate thickness.

(Other ingredients)
The photosensitive resin composition of this embodiment may, in addition to the above-mentioned components, optionally contain components other than those listed above. Examples of such components include antioxidants, fillers such as silica, sensitizers, and film-forming agents.

<Manufacturing methods for electronic devices, electronic devices>
The method for manufacturing the electronic device of this embodiment is:
A film formation step of forming a photosensitive resin film on a substrate using the above-mentioned photosensitive resin composition,
An exposure process for exposing a photosensitive resin film,
A developing process for developing an exposed photosensitive resin film,
Includes.
Furthermore, the manufacturing method of the electronic device in this embodiment preferably includes a thermosetting step after the development step described above, in which the exposed photosensitive resin film is heated and cured. This makes it possible to obtain a cured film with sufficient heat resistance.
As described above, an electronic device comprising a cured film of the photosensitive resin composition of this embodiment can be manufactured.

The manufacturing method of the electronic device of this embodiment, and the structure of the electronic device comprising the cured product of the photosensitive resin composition of this embodiment, will be described in more detail below with the help of drawings.

Figure 1 is a longitudinal cross-sectional view showing an example of the electronic device of this embodiment. Figure 2 is a partially enlarged view of the area enclosed by the dashed line in Figure 1.
In the following explanation, the upper part of Figure 1 will be referred to as "upper" and the lower part as "lower".

The electronic device 1 shown in Figure 1 has a so-called package-on-package structure, comprising a through-electrode substrate 2 and a semiconductor package 3 mounted thereon.

The through-electrode substrate 2 comprises an insulating layer 21, a plurality of through-wirings 221 penetrating from the upper surface to the lower surface of the insulating layer 21, a semiconductor chip 23 embedded inside the insulating layer 21, a lower wiring layer 24 provided on the lower surface of the insulating layer 21, an upper wiring layer 25 provided on the upper surface of the insulating layer 21, and solder bumps 26 provided on the lower surface of the lower wiring layer 24.

The semiconductor package 3 comprises a package substrate 31, a semiconductor chip 32 mounted on the package substrate 31, bonding wires 33 that electrically connect the semiconductor chip 32 and the package substrate 31, a sealing layer 34 in which the semiconductor chip 32 and bonding wires 33 are embedded, and solder bumps 35 provided on the lower surface of the package substrate 31.

The semiconductor package 3 is then stacked on the through-electrode substrate 2. This electrically connects the solder bumps 35 of the semiconductor package 3 to the upper wiring layer 25 of the through-electrode substrate 2.

In such an electronic device 1, there is no need to use a thick substrate, such as an organic substrate containing a core layer, in the through-electrode substrate 2, thus easily enabling a lower profile. Therefore, it can contribute to the miniaturization of electronic devices that incorporate the electronic device 1.

Furthermore, because the through-electrode substrate 2 and semiconductor package 3, each equipped with different semiconductor chips, are stacked, the mounting density per unit area can be increased. Therefore, it is possible to achieve both miniaturization and high performance.

The through-electrode substrate 2 and semiconductor package 3 will be described in more detail below.
The lower wiring layer 24 and upper wiring layer 25 of the through-electrode substrate 2 shown in Figure 2 each include an insulating layer, a wiring layer, and through-wiring, etc. As a result, the lower wiring layer 24 and upper wiring layer 25 include wiring inside and on the surface, and are electrically connected to each other via through-wiring 221 that penetrates the insulating layer 21.

The wiring layers included in the lower wiring layer 24 are connected to the semiconductor chip 23 and the solder bumps 26. Therefore, the lower wiring layer 24 functions as a rewiring layer for the semiconductor chip 23, and the solder bumps 26 function as external terminals for the semiconductor chip 23.

As mentioned above, the through-wiring 221 shown in Figure 2 is provided so as to penetrate the insulating layer 21. This electrically connects the lower wiring layer 24 and the upper wiring layer 25, enabling the lamination of the through-electrode substrate 2 and the semiconductor package 3, thereby improving the functionality of the electronic device 1.

The wiring layer 253 included in the upper wiring layer 25 shown in Figure 2 is connected to the through-wiring 221 and solder bumps 35. Therefore, the upper wiring layer 25 is electrically connected to the semiconductor chip 23, functioning as a redistribution layer for the semiconductor chip 23, and also as an interposer between the semiconductor chip 23 and the package substrate 31. The cured film of the photosensitive resin composition in this embodiment can be used to constitute the insulating layer of the redistribution layer.

According to this embodiment, an electronic device can be realized comprising a semiconductor chip 23 and a redistribution layer (upper distribution layer 25) provided on the surface of the semiconductor chip 23, wherein the insulating layer in the redistribution layer is composed of a cured product of the photosensitive resin composition of this embodiment.

Because the through-wiring 221 penetrates the insulating layer 21, it provides a reinforcing effect on the insulating layer 21. Therefore, even if the mechanical strength of the lower wiring layer 24 and the upper wiring layer 25 is low, a decrease in the overall mechanical strength of the through-electrode substrate 2 can be avoided. As a result, the lower wiring layer 24 and the upper wiring layer 25 can be further thinned, and the electronic device 1 can be made even lower in profile.

Furthermore, the electronic device 1 shown in Figure 1 includes, in addition to the through-wiring 221, a through-wiring 222 that penetrates the insulating layer 21 located on the upper surface of the semiconductor chip 23. This allows for electrical connection between the upper surface of the semiconductor chip 23 and the upper wiring layer 25.

The insulating layer 21 is provided so as to cover the semiconductor chip 23. This enhances the protective effect on the semiconductor chip 23. As a result, the reliability of the electronic device 1 can be improved. Furthermore, an electronic device 1 that can be easily applied to mounting methods such as the package-on-package structure according to this embodiment can be obtained.

The diameter W of the through-wiring 221 (see Figure 2) is not particularly limited, but is preferably about 1 to 100 μm, and more preferably about 2 to 80 μm. This ensures the conductivity of the through-wiring 221 without impairing the mechanical properties of the insulating layer 21.

The semiconductor package 3 shown in Figure 1 may be of any form. Examples include QFP (Quad Flat Package), SOP (Small Outline Package), BGA (Ball Grid Array), CSP (Chip Size Package), QFN (Quad Flat Non-leaded Package), SON (Small Outline Non-leaded Package), and LF-BGA (Lead Frame BGA).

The arrangement of the semiconductor chips 32 is not particularly limited, but as an example, Figure 1 shows multiple semiconductor chips 32 stacked on top of each other. This increases the density of the mounting. The multiple semiconductor chips 32 may be arranged side-by-side in the planar direction, or they may be stacked in the thickness direction while also being arranged side-by-side in the planar direction.

The package substrate 31 may be any substrate, but for example, it may include an insulating layer, a wiring layer, and through-wiring (not shown). Of these, the solder bumps 35 and bonding wires 33 can be electrically connected via the through-wiring.

The sealing layer 34 is made of, for example, a known sealing resin material. By providing such a sealing layer 34, the semiconductor chip 32 and bonding wires 33 can be protected from external forces and the external environment.

The semiconductor chip 23 on the through-electrode substrate 2 and the semiconductor chip 32 on the semiconductor package 3 are arranged in close proximity to each other. This allows for benefits such as faster and lower-loss communication between them. From this perspective, for example, if one of the semiconductor chips 23 and 32 is a computing element such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), or AP (Application Processor), and the other is a memory element such as a DRAM (Dynamic Random Access Memory) or flash memory, these elements can be arranged in close proximity within the same device. This makes it possible to realize an electronic device 1 that achieves both high functionality and miniaturization.

Next, the method for manufacturing the electronic device 1 shown in Figure 1 will be described.

Figure 3 is a process diagram showing the method for manufacturing the electronic device 1 shown in Figure 1. Figures 4 to 6 are diagrams illustrating the method for manufacturing the electronic device 1 shown in Figure 1.

The manufacturing method for the electronic device 1 includes: a chip placement step S1 for obtaining an insulating layer 21 to embed semiconductor chips 23 and through-wirings 221 and 222 on a substrate 202; an upper wiring layer formation step S2 for forming an upper wiring layer 25 on the insulating layer 21 and on the semiconductor chips 23; a substrate peeling step S3 for peeling off the substrate 202; a lower wiring layer formation step S4 for forming a lower wiring layer 24; a solder bump formation step S5 for forming solder bumps 26 and obtaining a through-electrode substrate 2; and a lamination step S6 for laminating a semiconductor package 3 on the through-electrode substrate 2.

Of these, the upper wiring layer formation step S2 includes a first resin film placement step S20 in which a photosensitive resin varnish 5 (a varnish-like photosensitive resin composition) is placed on the insulating layer 21 and the semiconductor chip 23 to obtain a photosensitive resin layer 2510; a first exposure step S21 in which the photosensitive resin layer 2510 is exposed; a first development step S22 in which the photosensitive resin layer 2510 is developed; a first curing step S23 in which the photosensitive resin layer 2510 is cured; and a wiring layer formation step in which the wiring layer 253 is formed. The process includes: step S24; a second resin film placement step S25 in which a photosensitive resin varnish 5 is placed on the photosensitive resin layer 2510 and the wiring layer 253 to obtain a photosensitive resin layer 2520; a second exposure step S26 in which the photosensitive resin layer 2520 is exposed; a second development step S27 in which the photosensitive resin layer 2520 is developed; a second curing step S28 in which the photosensitive resin layer 2520 is cured; and a through-wiring formation step S29 in which through-wiring 254 is formed in the opening 424 (through hole).

The following describes each step in order. The manufacturing method described below is just one example and is not limited to this method.

[1] Chip placement process S1
First, as shown in Figure 4(a), a chip embedding structure 27 is prepared, which includes a substrate 202, a semiconductor chip 23 and through-wirings 221 and 222 provided on the substrate 202, and an insulating layer 21 provided to embed these.

The constituent material of the substrate 202 is not particularly limited, but examples include metal materials, glass materials, ceramic materials, semiconductor materials, and organic materials. Furthermore, the substrate 202 may be made of semiconductor wafers such as silicon wafers, glass wafers, etc.

The semiconductor chip 23 is bonded to the substrate 202. In this manufacturing method, as an example, multiple semiconductor chips 23 are arranged on the same substrate 202, spaced apart from each other. The multiple semiconductor chips 23 may be of the same type or of different types. Alternatively, the substrate 202 and the semiconductor chips 23 may be fixed together via an adhesive layer (not shown), such as a die-attach film.

If necessary, an interposer (not shown) may be provided between the substrate 202 and the semiconductor chip 23. The interposer functions, for example, as a redistribution layer for the semiconductor chip 23. Therefore, the interposer may include pads (not shown) for electrically connecting to the electrodes of the semiconductor chip 23, which will be described later. This allows for changes in the pad spacing and arrangement pattern of the semiconductor chip 23, thereby increasing the design flexibility of the electronic device 1.
Interposers can utilize inorganic substrates such as silicon substrates, ceramic substrates, and glass substrates, as well as organic substrates such as resin substrates.

The insulating layer 21 may be a resin film (organic insulating layer) containing a thermosetting resin or thermoplastic resin, such as those listed as components of the photosensitive resin composition, or it may be a conventional encapsulant used in the semiconductor technology field.

Examples of materials used for the through-wiring 221 and 222 include copper or copper alloys, aluminum or aluminum alloys, gold or gold alloys, silver or silver alloys, nickel or nickel alloys, and the like.

Alternatively, a chip-embedded structure 27 manufactured using a method different from the one described above may be prepared.

[2] Upper wiring layer forming step S2
Next, an upper wiring layer 25 is formed on the insulating layer 21 and the semiconductor chip 23.

[2-1] First resin film arrangement step S20
First, as shown in Figure 4(b), the photosensitive resin varnish 5 is applied (placed) on the insulating layer 21 and the semiconductor chip 23. This results in a liquid film of the photosensitive resin varnish 5, as shown in Figure 4(c). The photosensitive resin varnish 5 is the photosensitive resin composition of this embodiment.

The photosensitive resin varnish 5 is applied using, for example, a spin coater, bar coater, spray device, inkjet device, etc.

The viscosity of the photosensitive resin varnish 5 is not particularly limited, but is 10 cP to 6000 cP, preferably 20 cP to 5000 cP, and more preferably 30 cP to 4000 cP. By having the viscosity of the photosensitive resin varnish 5 within the above range, a thinner photosensitive resin layer 2510 (see Figure 4(d)) can be formed. As a result, the upper wiring layer 25 can be made thinner, making it easier to thin the electronic device 1.
The viscosity of the photosensitive resin varnish 5 is, for example, the value measured using a cone-plate viscometer (TV-25, manufactured by Toki Sangyo Co., Ltd.) at a rotation speed of 100 rpm.

Next, the liquid film of the photosensitive resin varnish 5 is dried. This yields the photosensitive resin layer 2510 shown in Figure 4(d).

The drying conditions for the photosensitive resin varnish 5 are not particularly limited, but examples include heating at a temperature of 80 to 150°C for 1 to 60 minutes.

In this process, instead of applying the photosensitive resin varnish 5, a process of arranging a photosensitive resin film formed from the photosensitive resin varnish 5 may be adopted. The photosensitive resin film is a photosensitive resin film of the photosensitive resin composition of this embodiment.

A photosensitive resin film is manufactured, for example, by applying a photosensitive resin varnish 5 to a substrate such as a carrier film using various coating devices, and then drying the resulting coating.

After forming the photosensitive resin layer 2510 in this manner, the photosensitive resin layer 2510 is subjected to pre-exposure heat treatment as needed. By performing pre-exposure heat treatment, the molecules contained in the photosensitive resin layer 2510 are stabilized, thereby stabilizing the reaction in the first exposure step S21 described later. Furthermore, by heating under the heating conditions described later, the adverse effects of heating on the photoacid generator can be minimized.

The temperature of the pre-exposure heat treatment is preferably 70 to 130°C, more preferably 75 to 120°C, and even more preferably 80 to 110°C. If the temperature of the pre-exposure heat treatment falls below the lower limit, the objective of stabilizing the molecules through the pre-exposure heat treatment may not be achieved. On the other hand, if the temperature of the pre-exposure heat treatment exceeds the upper limit, the photoacid generator becomes too active, and the effect of reduced acid generation even when light is irradiated in the first exposure step S21 (described later) becomes widespread, potentially reducing the processing accuracy of the patterning.

The time for pre-exposure heat treatment is set appropriately according to the temperature of the pre-exposure heat treatment, but is preferably 1 to 10 minutes, more preferably 2 to 8 minutes, and even more preferably 3 to 6 minutes at the aforementioned temperature. If the time for pre-exposure heat treatment falls below the lower limit, the heating time will be insufficient, and the objective of stabilizing the molecules by pre-exposure heat treatment may not be achieved. On the other hand, if the time for pre-exposure heat treatment exceeds the upper limit, the heating time will be too long, and even if the temperature of the pre-exposure heat treatment falls within the aforementioned range, the action of the photoacid generator may be inhibited.

The atmosphere used for the heat treatment is not particularly limited. An inert gas atmosphere or a reducing gas atmosphere may be used, but considering work efficiency, air is preferred.

The ambient pressure is not particularly limited. It may be under reduced or increased pressure, but considering work efficiency, atmospheric pressure is preferred. Atmospheric pressure refers to a pressure of approximately 30 to 150 kPa, preferably atmospheric pressure.

[2-2] First exposure process S21
Next, the photosensitive resin layer 2510 is subjected to exposure treatment.

First, as shown in Figure 4(d), a mask 412 is placed in a predetermined area on the photosensitive resin layer 2510. Then, light (active radiation) is irradiated through the mask 412. This exposes the photosensitive resin layer 2510 according to the pattern of the mask 412.

Figure 4(d) illustrates a case where the photosensitive resin layer 2510 has so-called negative-type photosensitivity. In this example, the portion of the photosensitive resin layer 2510 corresponding to the light-shielding area of the mask 412 is dissolved in the developer solution.

On the other hand, in the region corresponding to the permeable area of mask 412, activated chemical species are generated from the photocationic polymerization initiator. These activated chemical species act as catalysts for the curing reaction.

The exposure amount in the exposure process is not particularly limited. 100 to 2000 mJ/ ^cm² is preferred, and 200 to 1000 mJ/ ^cm² is more preferred. This suppresses underexposure and overexposure in the photosensitive resin layer 2510. As a result, high patterning accuracy can ultimately be achieved.
Subsequently, if necessary, the photosensitive resin layer 2510 is subjected to post-exposure heat treatment.

The temperature of the post-exposure heat treatment is not particularly limited. Preferably, it is 50 to 150°C, more preferably 50 to 130°C, even more preferably 55 to 120°C, and most preferably 60 to 110°C. By performing the post-exposure heat treatment at such temperatures, the catalytic action of the generated acid is sufficiently enhanced, allowing the thermosetting resin to react more quickly and thoroughly. By keeping the temperature within the above range, a decrease in the processing accuracy of the patterning due to accelerated acid diffusion can be suppressed.
By setting the post-exposure heat treatment temperature above the lower limit, the reaction rate of the thermosetting resin can be increased, thereby improving productivity. On the other hand, by setting the post-exposure heat treatment temperature below the upper limit, the decrease in patterning accuracy due to accelerated acid diffusion can be suppressed.

The duration of the post-exposure heat treatment is set appropriately according to the post-exposure heat treatment temperature. At the above temperature, it is preferably 1 to 30 minutes, more preferably 2 to 20 minutes, and even more preferably 3 to 15 minutes. By performing the post-exposure heat treatment for such a duration, the thermosetting resin can be sufficiently reacted, and the diffusion of acid can be suppressed, thereby preventing a decrease in the processing accuracy of the patterning.

The atmosphere for post-exposure heat treatment is not particularly limited. An inert gas atmosphere or a reducing gas atmosphere may be used, but considering work efficiency, air is preferred.

The atmospheric pressure for the post-exposure heat treatment is not particularly limited. It may be under reduced or increased pressure, but considering work efficiency, atmospheric pressure is preferred. This allows for relatively easy pre-exposure heat treatment. Atmospheric pressure refers to a pressure of approximately 30 to 150 kPa, preferably atmospheric pressure.

[2-3] First development step S22
Next, the photosensitive resin layer 2510 is subjected to a developing process. This creates an opening 423 that penetrates the photosensitive resin layer 2510 in the area corresponding to the light-shielding portion of the mask 412 (see Figure 5(e)).

Examples of developers include organic developers and water-soluble developers. In this embodiment, it is preferable that the developer contains an organic solvent. More specifically, it is preferable that the developer is a developer whose main component is an organic solvent (a developer in which 95% or more by mass of the components is an organic solvent). Developing with a developer containing an organic solvent makes it possible to suppress the swelling of the pattern caused by the developer compared to developing with an alkaline developer (water-based). In other words, it is easier to obtain a finer pattern.

Examples of organic solvents that can be used in developing solutions include ketone solvents such as cyclopentanone, ester solvents such as propylene glycol monomethyl ether acetate (PGMEA) and butyl acetate, and ether solvents such as propylene glycol monomethyl ether.
As a developer, an organic solvent developer consisting solely of organic solvents and containing no impurities other than those inevitably present may be used. Inevitable impurities include metallic elements and water, but from the perspective of preventing contamination of electronic devices, it is better to have as few unavoidable impurities as possible.

The method for bringing the developing solution into contact with the photosensitive resin layer 2510 is not particularly limited. Generally known methods such as immersion, paddle, and spray can be applied as appropriate.

The development process time is typically within a range of 5 to 300 seconds, preferably 10 to 120 seconds, and is appropriately adjusted based on factors such as the thickness of the resin film and the shape of the formed pattern.

[2-4] First curing step S23
After development, the photosensitive resin layer 2510 is subjected to a curing treatment (post-development heat treatment). The conditions for the curing treatment are not particularly limited, but are generally set to a heating temperature of approximately 160 to 250°C for a heating time of approximately 30 to 240 minutes. This allows the photosensitive resin layer 2510 to be cured while suppressing the thermal impact on the semiconductor chip 23, thereby obtaining the organic insulating layer 251.

[2-5] Wiring layer forming step S24
Next, a wiring layer 253 is formed on the organic insulating layer 251 (see Figure 5(f)). The wiring layer 253 is formed by obtaining a metal layer using a vapor deposition method such as sputtering or vacuum deposition, and then patterning it using photolithography and etching.
Prior to the formation of the wiring layer 253, a surface modification treatment such as plasma treatment may be performed.

[2-6] Second resin film arrangement step S25
Next, as shown in Figure 5(g), a photosensitive resin layer 2520 is obtained in the same manner as in the first resin film arrangement step S20. The photosensitive resin layer 2520 is arranged to cover the wiring layer 253.
Subsequently, if necessary, the photosensitive resin layer 2520 is subjected to pre-exposure heat treatment. The treatment conditions are, for example, those described in the first resin film arrangement step S20.

[2-7] Second lithography process S26
Next, the photosensitive resin layer 2520 is subjected to exposure treatment. The treatment conditions are, for example, those described in the first exposure step S21.
Subsequently, if necessary, the photosensitive resin layer 2520 is subjected to post-exposure heat treatment. The treatment conditions are, for example, those described in the first exposure step S21.

[2-8] Second development step S27
Next, the photosensitive resin layer 2520 is subjected to a developing process. The processing conditions are, for example, those described in the first developing step S22. This creates openings 424 that penetrate the photosensitive resin layers 2510 and 2520 (see Figure 5(h)).

[2-9] Second curing step S28
After the development process, the photosensitive resin layer 2520 is subjected to a curing treatment (post-development heat treatment). The curing conditions are, for example, those described in the first curing step S23. This cures the photosensitive resin layer 2520 and obtains the organic insulating layer 252 (see Figure 6(i)).

In this embodiment, the upper wiring layer 25 has two layers, an organic insulating layer 251 and an organic insulating layer 252, but it may have three or more layers. In this case, after the second curing step S28, the series of steps from the wiring layer formation step S24 to the second curing step S28 can be repeated.

[2-10] Through-hole wiring formation step S29
Next, a through-wiring 254, as shown in Figure 6(i), is formed in the opening 424.

Known methods can be used to form the through-wiring 254; for example, the following method can be used.

First, a seed layer (not shown) is formed on the organic insulating layer 252. The seed layer is formed on the upper surface of the organic insulating layer 252, along with the inner surface (sides and bottom) of the opening 424.
For example, a copper seed layer is used as the seed layer. The seed layer is formed by, for example, a sputtering method.
The seed layer may be made of the same type of metal as the through-wiring 254 to be formed, or it may be made of a different type of metal.

Next, a resist layer (not shown) is formed on the area of the seed layer (not shown) other than the opening 424. Then, using this resist layer as a mask, metal is filled into the opening 424. For this filling, for example, electroplating is used. Examples of the metal used for filling include copper or copper alloys, aluminum or aluminum alloys, gold or gold alloys, silver or silver alloys, nickel or nickel alloys, etc. In this way, conductive material is embedded in the opening 424, and the through-wiring 254 is formed.

Next, a resist layer (not shown) is removed. Furthermore, a seed layer (not shown) on the organic insulating layer 252 is removed. For this, a flash etching method can be used, for example.
The location where the through-wiring 254 is formed is not limited to the position shown in the figure.

[3] Substrate peeling process S3
Next, as shown in Figure 6(j), the substrate 202 is peeled off. This exposes the lower surface of the insulating layer 21.

[4] Lower wiring layer forming step S4
Next, as shown in Figure 6(k), a lower wiring layer 24 is formed on the lower side of the insulating layer 21. The lower wiring layer 24 may be formed by any method, for example, in the same manner as the upper wiring layer formation step S2 described above.
The lower wiring layer 24 formed in this manner is electrically connected to the upper wiring layer 25 via through-wiring 221.

[5] Solder bump formation process S5
Next, as shown in Figure 6(L), solder bumps 26 are formed on the lower wiring layer 24. Additionally, a protective film, such as a solder resist layer, may be formed on the upper wiring layer 25 and the lower wiring layer 24 as needed.
As described above, the through-electrode substrate 2 is obtained.

The through-electrode substrate 2 shown in Figure 6(L) is divisible into multiple regions. Therefore, by separating the through-electrode substrate 2 along the dashed-dotted line shown in Figure 6(L), for example, multiple through-electrode substrates 2 can be efficiently manufactured. A diamond cutter, for example, can be used for this separation.

[6] Lamination process S6
Next, the semiconductor package 3 is placed on the individualized through-electrode substrate 2. This results in the electronic device 1 shown in Figure 1.

This method for manufacturing the electronic device 1 can be applied to wafer-level processes and panel-level processes using large-area substrates. This allows for increased manufacturing efficiency and reduced costs for the electronic device 1.

Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted. Furthermore, the present invention is not limited to the embodiments described above, and modifications, improvements, etc., within the scope that can achieve the objectives of the present invention are included in the present invention.
Examples of reference formats are provided below.
1. Polyimide (A) having an imide ring structure,
Polyfunctional (meth)acrylate compound (B),
Photosensitive material (C),
Solvent (J) and,
A photosensitive resin composition containing [the specified element].
2.
1. The photosensitive resin composition described in,
Let IM be the number of moles of imide groups contained in the polyimide (A) mentioned above.
When AM is the number of moles of amide groups contained in the polyimide (A),
A photosensitive resin composition having an imidization rate of 90% or more, expressed as {IM/(IM+AM)} × 100 (%).
3.
A photosensitive resin composition as described in 1. or 2.,
A photosensitive resin composition wherein the polyimide (A) contains a structure represented by the above-mentioned general formula (a).
In general formula (a),
X is a divalent organic group,
Y is a tetravalent organic group,
At least one of X and Y is a fluorine atom-containing group.
4.
A photosensitive resin composition according to any one of 1. to 3.
The polyimide (A) is a photosensitive resin composition comprising a polyimide containing a fluorine atom.
5.
A photosensitive resin composition according to any one of 1. to 4.,
The polyimide (A) is a photosensitive resin composition having a group at its end that can react with and bond with an epoxy group.
6.
A photosensitive resin composition according to any one of 1. to 5.
The polyimide (A) is a photosensitive resin composition having an acid anhydride group at its terminal end.
7.
A photosensitive resin composition according to any one of 1. to 6.,
The polyimide (A) is a photosensitive resin composition that does not have a maleimide structure at its terminal end.
8.
A photosensitive resin composition according to any one of 1. to 7.
A photosensitive resin composition wherein the polyfunctional (meth)acrylate compound (B) comprises a heptafunctional (meth)acrylate compound (B1).
9.
A photosensitive resin composition according to any one of 1. to 8.
A photosensitive resin composition wherein the polyfunctional (meth)acrylate compound (B) comprises a 5- to 6-functional (meth)acrylate compound (B2).
10.
A photosensitive resin composition according to any one of 1. to 9.
A photosensitive resin composition wherein the polyfunctional (meth)acrylate compound (B) comprises a trifunctional (meth)acrylate compound (B3).
11.
A photosensitive resin composition according to any one of 1. to 10.
A photosensitive resin composition in which the amount of the polyfunctional (meth)acrylate compound (B) is 50 to 150 parts by mass per 100 parts by mass of the polyimide (A).
12.
1. A photosensitive resin composition according to any one of the following:
A photosensitive resin composition in which the amount of the polyfunctional (meth)acrylate compound (B) is 70 to 120 parts by mass per 100 parts by mass of the polyimide (A).
13.
A photosensitive resin composition according to any one of 1. to 12.
A photosensitive resin composition wherein the photosensitive agent (C) contains a photoradical generator.
14.
A photosensitive resin composition according to any one of 1. to 13.
Furthermore, a photosensitive resin composition comprising a thermal radical initiator (D).
15.
14. The photosensitive resin composition described above,
A photosensitive resin composition wherein the thermal radical initiator (D) contains an organic peroxide.
16.
A photosensitive resin composition as described in 14. or 15.,
A photosensitive resin composition in which the amount of the thermal radical initiator (D) is 0.1 to 20 parts by mass per 100 parts by mass of the polyfunctional (meth)acrylate compound (B).
17.
A photosensitive resin composition according to any one of 1. to 16.
Furthermore, a photosensitive resin composition containing epoxy resin (E).
18.
17. The photosensitive resin composition described above,
Furthermore, a photosensitive resin composition comprising a curing catalyst (F) for the epoxy resin (E).
19.
A photosensitive resin composition according to any one of 1. to 18.
Furthermore, a photosensitive resin composition containing a silane coupling agent (G).
20.
19. The photosensitive resin composition described above,
A photosensitive resin composition comprising a silane coupling agent (G) having a cyclic anhydride structure.
21.
A photosensitive resin composition according to any one of 1. to 20.
Furthermore, a photosensitive resin composition containing a surfactant (H).
22.
A photosensitive resin composition according to any one of 1. to 21.
A photosensitive resin composition in which the proportion of the polyimide (A) and the polyfunctional (meth)acrylate compound (B) in the whole composition is 20 to 50% by mass.
23.
A photosensitive resin composition according to any one of 1. to 22.
A photosensitive resin composition in which at least the polyimide (A) and the polyfunctional (meth)acrylate compound (B) are dissolved in the solvent (J) in a varnish-like form.
24.
A photosensitive resin composition according to any one of 1. to 23.
A photosensitive resin composition used for forming an insulating layer in electronic devices.
25.
A film formation step of forming a photosensitive resin film on a substrate using any one of the photosensitive resin compositions described in 1. to 24.,
An exposure step of exposing the photosensitive resin film,
A developing step for developing the exposed photosensitive resin film,
A method for manufacturing electronic devices, including
26.
A method for manufacturing an electronic device as described in 25.
A method for manufacturing an electronic device, comprising a thermosetting step of heating and curing the exposed photosensitive resin film after the development step.
27.
An electronic device comprising a cured film of a photosensitive resin composition as described in any one of 1. to 24.

Embodiments of the present invention will be described in detail based on examples and comparative examples. It should be noted that the present invention is not limited to these examples.
In the following, "DMAc" is an abbreviation for dimethylacetamide. Other abbreviations will be explained as appropriate in the text.

<Polymer synthesis>
(Synthesis of polymer (A-1))
In a 3 L separable glass flask equipped with a stirrer and stirring blades, 64.1 g (0.20 mol) of TFMB <2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl>, 97.7 g (0.22 mol) of 6FDA <4,4'-(hexafluoroisopropylidene)diphthalic acid dianhydride>, and 500 g of DMAc were charged and stirred to dissolve the TFMB and 6FDA in the DMAc. Further stirring was carried out at room temperature under a nitrogen stream for 12 hours to obtain a polyamic acid solution.

After adding 16 g of pyridine to the obtained polyamic acid solution, 82 g of acetic anhydride was added dropwise at room temperature. The mixture was then stirred for 24 hours while maintaining the temperature at 20-100°C to carry out the imidation reaction, yielding a polyimide solution.

The obtained polyimide solution was added to 1,000 g of methanol in a 5 L container while stirring to precipitate the polyimide resin. The solid polyimide resin was then filtered off using a suction filtration device and washed with another 1,000 g of methanol. Finally, it was dried in a vacuum dryer at 100°C for 24 hours, and then at 200°C for 3 hours. Through these steps, polymer (A-1), a polyimide powder having acid anhydride groups at its ends, was obtained.
The weight-average molecular weight (Mw) of polymer (A-1), as determined by GPC measurement, was 25,000.
Furthermore, polymer (A-1) was subjected to ^1H -NMR measurement, and the imidization rate (defined as above) was calculated from the quantitative value of the amide peak relative to the aromatic ring peak of the polyimide. The imidization rate was 99% or higher.

(Synthesis of polymer (A-2))
Polymer synthesis was carried out in the same manner as in Example 1, except that 56.4 g (0.176 mol) of TFMB and 12.4 g (0.024 mol) of BAPP-F <2,2,-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane> were used instead of 64.1 g (0.20 mol) of TFMB. A polymer (A-2), which is a polyimide powder having acid anhydride groups at its termini, was obtained.
The weight-average molecular weight (Mw) of polymer (A-2), as determined by GPC, was 26,000. Furthermore, the imidization rate of polymer (A-2), as determined by NMR, was over 99%.

(Synthesis of polymer (A-3))
Polymer synthesis was carried out in the same manner as in Example 1, except that 78.2 g (0.176 mol) of 6FDA and 13.7 g (0.044 mol) of ODPA <4,4'-oxydiphthalic acid dianhydride> were used instead of 97.7 g (0.22 mol) of 6FDA. A polymer (A-3), which is a polyimide powder having acid anhydride groups at its termini, was obtained.
The weight-average molecular weight (Mw) of polymer (A-3), as determined by GPC, was 24,000. Furthermore, the imidization rate of polymer (A-3), as determined by NMR, was over 99%.

(Synthesis of polymer (A-4))
Polymer synthesis was carried out in the same manner as in Example 1, except that 83.1 g (0.187 mol) of 6FDA and 9.71 g (0.033 mol) of BPDA <3,3',4,4'-biphenyltetracarboxylic dianhydride> were used instead of 97.7 g (0.22 mol) of 6FDA. A polyimide resin (A-4) having acid anhydride groups at the terminals was obtained.
The weight-average molecular weight (Mw) of polymer (A-4), as determined by GPC, was 24,000. Furthermore, the imidization rate of polymer (A-4), as determined by NMR, was over 99%.

(Synthesis of polymer (A-5) (for comparison))
428 g of γ-butyrolactone, 155.11 g of 4,4'-oxydiphthalic acid dianhydride, and 130.14 g of 2-hydroxyethyl methacrylate were placed in a 2 L separable flask, and the components in the flask were stirred at room temperature until completely dissolved. Subsequently, 79.1 g of pyridine was added while stirring at room temperature, and the mixture was stirred further at room temperature for 16 hours.

The solution obtained as described above was cooled and stirred under ice, and a solution of 206.3 g of dicyclohexylcarbodiimide dissolved in 206 g of γ-butyrolactone was added to the solution over 30 minutes. Subsequently, 120.1 g of 4,4'-diaminodiphenyl ether and 240 g of γ-butyrolactone were added, and stirring was continued at room temperature for a further 2 hours.
After the reaction was complete, 30 g of ethanol was added and the mixture was stirred for 1 hour. Then, 400 g of γ-butyrolactone was added and the mixture was stirred further, and the resulting precipitate was removed by filtration. This yielded the reaction solution of the polyamic acid ester.
The resulting reaction solution was added dropwise to a large amount of 30% by mass methanol aqueous solution at room temperature while stirring, and the polymer was precipitated. The resulting precipitate was filtered and vacuum-dried to obtain poly-c(A-5).
The weight-average molecular weight (Mw) of polymer (A-5) measured by GPC was 18,000. Furthermore, the imidization rate of polymer (A-5) measured by NMR was less than 1%.

<Preparation of photosensitive resin composition>
Each raw material, formulated according to Table 1 shown below, was stirred at room temperature until the raw materials were completely dissolved to obtain a solution. The solution was then filtered through a nylon filter with a pore size of 0.2 μm. In this way, a varnish-like photosensitive resin composition was obtained.

The details of the raw materials for each component in Table 1 are as follows:

<(A) Polyimide>
(A-1) Polymer synthesized as described above (polyimide resin containing imide ring structure)
(A-2) Polymer synthesized as described above (polyimide resin containing imide ring structure)
(A-3) Polymer synthesized as described above (polyimide resin containing imide ring structure)
(A-4) Polymer synthesized as described above (polyimide resin containing imide ring structure)
(A-5) Polymer synthesized above (polyamic acid ester resin (for comparative example))

The structures of each of the above polymers are shown below.

<(B) Polyfunctional (meth)acrylate compounds>
(B-1) Viscoat #802 (Manufactured by Osaka Organic Industry Co., Ltd.)
(A mixture of compounds having 5 to 10 acryloyl groups)
(B-2) A-9550 (Manufactured by Shin-Nakamura Chemical Co., Ltd.)
(A mixture of compounds having 5 to 6 acryloyl groups)
(B-3) Viscoat #300 (Manufactured by Osaka Organic Industry Co., Ltd.)
(A mixture of compounds having 3 to 4 acryloyl groups)
(B-4) Viscoat #230 (Manufactured by Osaka Organic Industry Co., Ltd.)
(A compound having two acryloyl groups)

The structures of (B-1) to (B-4) above are shown below.

<(C) Photosensitive agent>
(C-1) Irugacure OXE01 (BASF Corporation, oxime ester type photoradical generator)
(C-2) ADEKA Arcluz NCI-730 (manufactured by ADEKA Corporation, oxime ester type photoradical generator)

<(D) Thermal radical generator>
(D-1) Percadox BC (manufactured by Kayaku Nurion Co., Ltd., organic peroxide, cumyl peroxide)

<(E) Epoxy resin>
(E-1) TECHMORE VG3101L (manufactured by Printec Co., Ltd.)
(E-2) Celoxide 2021P (manufactured by Daicel Corporation)

<(F) Curing catalyst>
(F-1) Tetraphenylphosphonium 4,4'-sulfonyl diphenolate The synthesis method for the above curing catalyst (F-1) is as follows.
In a separable flask equipped with a stirrer, 37.5 g (0.15 mol) of 4,4'-bisphenol S and 100 mL of methanol were charged and stirred to dissolve at room temperature. While continuing to stir, a solution of 4.0 g (0.1 mol) of sodium hydroxide dissolved in 50 mL of methanol was added. Next, a solution of 41.9 g (0.1 mol) of tetraphenylphosphonium bromide dissolved in 150 mL of methanol was added. Stirring was continued for a while, and after adding 300 mL of methanol, the solution in the flask was added dropwise to a large amount of water while stirring to obtain a white precipitate. The precipitate was filtered and dried. The target product, a white crystal, was obtained by the above procedure.

<(G) Silane coupling agent>
(G-1) KBM-503 (manufactured by Shin-Etsu Chemical Co., Ltd.)
(G-2) X-12-967C (manufactured by Shin-Etsu Chemical Co., Ltd.)

<(H) Surfactants>
(H-1) FC4432 (manufactured by 3M, fluorine-based)

<(J)(solvent)>
(J-1) Ethyl lactate (EL)
(J-2) γ-butyrolactone (GBL)

<Evaluation of hardening shrinkage rate>
A photosensitive resin composition was spin-coated onto an 8-inch silicon wafer to a dry film thickness of 10 μm. Subsequently, the wafer was heated at 120°C for 3 minutes to obtain a photosensitive resin film.
The obtained photosensitive resin film was exposed to a high-pressure mercury lamp at 300 mJ/ ^cm² . Afterward, it was immersed in cyclopentanone for 30 seconds, followed by spin-drying to obtain a developed film of the photosensitive resin composition. The film thickness of this developed film was measured and defined as film thickness A.
Furthermore, the film was cured after development by heat treatment at 170°C for 90 minutes under a nitrogen atmosphere. A cured film of the photosensitive resin composition was obtained. The thickness of this cured film was measured and designated as film thickness B.
The curing shrinkage rate was calculated by substituting film thickness A and film thickness B into the following formula. A smaller curing shrinkage rate is preferable in order to maintain flatness after application to the wiring.
Curing shrinkage rate [%] = {(Film thickness A - Film thickness B) / Film thickness A} × 100

<Evaluation of flatness during application (flatness for filling steps)>
A Cu wiring substrate was fabricated by forming Cu wiring with a width of 5 μm, a pitch of 5 μm, and a height of 5 μm on a silicon wafer with an oxide film. A photosensitive resin composition was applied to this Cu wiring substrate by spin coating to a film thickness of 10 μm after drying, and the photosensitive resin film was formed by drying at 120°C for 3 minutes.
The resulting photosensitive resin film was exposed to a high-pressure mercury lamp at 300 mJ/ ^cm² . It was then immersed in cyclopentanone for 30 seconds. Finally, it was heat-treated at 170°C for 90 minutes under a nitrogen atmosphere to form a cured film on the substrate.
The resulting cured film-coated substrates were broken, their cross-sections were polished, and the surface roughness of the photosensitive resin film was evaluated by cross-sectional SEM observation. Surface roughness of 1 μm or less was rated as ○ (good), surface roughness of 1 to 3 μm was rated as △ (usable level), and surface roughness exceeding 3 μm was rated as × (bad).

<Heat resistance: Evaluation of glass transition temperature (Tg)>
(Preparation of test specimens for measuring glass transition temperature (Tg))
A photosensitive resin composition was spin-coated onto an 8-inch silicon wafer to obtain a photosensitive resin film with a dry film thickness of 10 μm, followed by heating at 120°C for 3 minutes.
The obtained photosensitive resin film was exposed to a high-pressure mercury lamp at 300 mJ/ ^cm² . The exposed resin film, along with the silicon wafer, was then immersed in cyclopentanone for 30 seconds. Finally, it was heat-treated at 170°C for 90 minutes under a nitrogen atmosphere. This process yielded a cured photosensitive resin composition.
The resulting cured material was cut along with the silicon wafer using a dicing saw to a width of 5 mm, and then peeled off the substrate by immersion in a 2% hydrofluoric acid aqueous solution. The peeled film was dried at 60°C for 10 hours to obtain a test piece (30 mm × 5 mm × 10 μm thick).

(Measurement of glass transition temperature (Tg))
Using a thermomechanical analyzer (Seiko Instruments, TMA/SS6000), the obtained test specimens were heated to 300°C at a heating rate of 10°C/min, and the thermal expansion coefficient of the obtained test specimens was measured.
Next, based on the obtained measurement results, the glass transition temperature (Tg) of the hardened material was calculated from the inflection point of the thermal expansion coefficient. The unit of Tg is °C. For samples where no inflection point was observed in the thermal expansion coefficient, the evaluation was based on Tg > 300°C.

<Measurement of tensile elongation>
First, a test specimen was prepared in the same manner as described in "Preparation of a test specimen for measuring the glass transition temperature (Tg)" above.
The obtained test specimens were subjected to tensile testing using a tensile testing machine (Tensilon RTC-1210A, manufactured by Orientec Co., Ltd.) under a 23°C atmosphere, in accordance with the method compliant with JIS K 7161, and the tensile elongation of the test specimens was measured. The stretching speed in the tensile test was set to 5 mm/min. The unit of tensile elongation is %.

<Evaluation of patternability>
A photosensitive resin composition was applied to an 8-inch silicon wafer using a spin coater to achieve a film thickness of 5 μm after drying. The film was then dried on a hot plate at 100°C for 3 minutes to obtain a photosensitive resin film (photosensitive resin film A).
This photosensitive resin film was irradiated with i-lines using an i-line stepper (Nikon NSR-4425i) while varying the exposure amount, through a Toppan Printing Co., Ltd. mask (Test Chart No. 1: showing retained and cut-out patterns with widths of 0.5 to 50 μm).
Subsequently, the film was developed using cyclopentanone as the developer for 30 seconds, then spun at 2500 rpm for 10 seconds to dry, and a post-development film (negative pattern) was obtained.
We evaluated the results as follows: a beer hole with a diameter of 7 μm was marked ◎ (very good), a beer hole with a diameter of 10 μm was marked ○ (good), and a beer hole with no diameter of 10 μm was marked × (bad).

<Evaluation of viscosity change rate at room temperature>
The viscosity of the photosensitive resin composition immediately after compounding was measured using an E-type viscometer (TVE-25L). This viscosity was designated as A. Subsequently, the varnish of the photosensitive resin composition was stored at 23°C for 7 days, and the viscosity was measured again. This viscosity was designated as B.
The viscosity change rate was calculated by substituting viscosity A and viscosity B into the following formula. A viscosity change rate of 5% or less was evaluated as ◎ (very good), 5 to 10% as ○ (good), and over 10% as × (bad). A lower viscosity change rate is preferable in order to obtain a stable film thickness.
Viscosity change rate [%] = {(Viscosity A - Viscosity B) / Viscosity A} × 100

<Evaluation of chemical resistance>
A photosensitive resin composition was spin-coated onto an 8-inch silicon wafer to obtain a photosensitive resin film with a dry film thickness of 10 μm, followed by heating at 120°C for 3 minutes.
The obtained photosensitive resin film was exposed to high-pressure mercury lamp at 300 mJ/ ^cm² . It was then immersed in cyclopentanone for 30 seconds. Finally, it was heat-treated under a nitrogen atmosphere at 170°C for 90 minutes to cure the photosensitive resin composition. The film thickness of the resulting cured film was measured. This film thickness was defined as film thickness A.
Next, the obtained cured film was immersed in dimethyl sulfoxide at 50°C for 30 minutes. After that, it was washed with isopropanol and dried with an air blower. Subsequently, it was heat-treated on a hot plate at 170°C for 5 minutes. In this way, a post-chemical resistance test film was obtained. The thickness of the obtained cured film was measured. This thickness was designated as film thickness B.
The film thickness change rate was calculated by substituting film thickness A and film thickness B into the following formula. A film thickness change rate of 5% or less was evaluated as ◎ (very good), 5 to 10% as ○ (good), and over 10% as × (bad). A smaller film thickness change rate is preferable in terms of chemical resistance during the process.
Film thickness change rate [%] = {(Film thickness A - Film thickness B) / Film thickness A} × 100

<Evaluation of insulation reliability>
(Preparation of samples for insulation reliability testing)
A Cu wiring substrate was fabricated by forming comb-shaped Cu wiring with a width of 5 μm, a pitch of 5 μm, and a height of 5 μm on a silicon wafer with an oxide film.
A photosensitive resin composition was applied to the Cu wiring substrate by spin coating so that the film thickness after drying (thickness in areas without wiring) was 10 μm, and the photosensitive resin film was formed by drying at 120°C for 3 minutes.
The obtained photosensitive resin film was exposed to a high-pressure mercury lamp at 300 mJ/ ^cm² . It was then immersed in cyclopentanone for 30 seconds. Finally, it was heat-treated at 170°C for 90 minutes under a nitrogen atmosphere to obtain a cured film. This was used as a sample for insulation reliability evaluation.

(Insulation reliability evaluation)
A simulated electronic device for evaluation was fabricated by soldering the ends (Cu electrodes) of the Cu wiring on the substrate prepared in the above (Sample Preparation for Insulation Reliability) to the electrode wiring. This device was then placed in a B-HAST apparatus under a bias of 3.5V and in an environment of 130°C/85%RH.
The insulation resistance between Cu wires on the Cu wiring board was automatically measured at 6-minute intervals, and dielectric breakdown was defined as the insulation resistance falling below 1.0 × ^10⁴ Ω. The time (h) from the start of the test to dielectric breakdown was then measured. In the table below, a time of 210 hours or more is marked with ◎ (very good), 50 to 210 hours with ○ (good), and less than 50 hours with × (bad).

The raw material formulations for each composition and the evaluation results are summarized in Table 1.

As shown in Table 1, the curing shrinkage rate was small in the evaluation of the photosensitive resin compositions of Examples 1 to 17. Furthermore, by using the photosensitive resin compositions of Examples 1 to 17, it was possible to form a cured film with good flatness on a substrate with steps. In addition, the photosensitive resin compositions of Examples 1 to 17 showed good results in various other performance aspects as well.
On the other hand, the curing shrinkage rate of the photosensitive resin composition of Comparative Example 1 was extremely large, and it was not possible to form a cured film with good flatness. This is presumed to be because the curing mechanism of the photosensitive resin composition of Comparative Example 1 involves ring closure of the polyamide resin, and dehydration occurred during the curing process.

A closer look at the examples reveals the following:
From a comparison between Example 15 and other examples, the use of a curing catalyst is preferable from the viewpoint of improving tensile elongation. It is thought that the curing catalyst's ability to sufficiently react with the epoxy resin contributes to the improvement of tensile elongation.
- Comparing Example 16 with the other examples, it is thought that the presence of water likely allows the adhesion aid to work more effectively, improving adhesion.
Based on a comparison between Example 17 and other examples, it is considered that polyfunctional (meth)acrylates with three or more functions are preferable to those with two functions.
Examples 7-9 demonstrate that using polyfunctional (meth)acrylates with a large number of functional groups improves chemical resistance, while using polyfunctional (meth)acrylates with a small number of functional groups improves tensile elongation.

1 Electronic device 1A Electronic device 1B Electronic device 2 Through electrode substrate 3 Semiconductor package 5 Photosensitive resin varnish 21 Insulating layer 23 Semiconductor chip 24 Lower wiring layer 24A Lower wiring layer 24B Lower wiring layer 25 Upper wiring layer 26 Solder bump 27 Chip embedded structure 31 Package substrate 32 Semiconductor chip 33 Bonding wire 34 Encapsulation layer 35 Solder bump 202 Substrate 221 Through wiring 222 Through wiring 231 Land 240 Organic insulating layer 241 Organic insulating layer 242 Organic insulating layer 243 Wiring layer 245 Bump adhesion layer 251 Organic insulating layer 252 Organic insulating layer 253 Wiring layer 254 Through wiring 412 Mask 423 Opening 424 Opening 2510 Photosensitive resin layer 2520 Photosensitive resin layer S1 Chip placement process S2 Upper wiring layer formation step S20 First resin film placement step S21 First exposure step S22 First development step S23 First curing step S24 Wiring layer formation step S25 Second resin film placement step S26 Second exposure step S27 Second development step S28 Second curing step S29 Through wiring formation step S3 Substrate peeling step S4 Lower wiring layer formation step S5 Solder bump formation step S6 Lamination process W diameter

Claims (20)

Polyimide (A) having an imide ring structure (not polyamideimide) ,
Polyfunctional (meth)acrylate compound (B),
Photosensitive material (C),
Solvent (J) and,
It contains as an essential component ,
The product may contain one or more of the following as optional components: thermal radical initiator (D), epoxy resin (E), curing catalyst (F), silane coupling agent (G), surfactant (H), water (I), antioxidant, filler, sensitizer, and film-forming agent, but it shall not contain any components other than the essential components and the optional components.
The polyimide (A) has a group at its end that can react with an epoxy group to form a bond,
The polyfunctional (meth)acrylate compound (B) comprises a 5-6 functional (meth)acrylate compound (B2),
The amount of the polyfunctional (meth)acrylate compound (B) relative to 100 parts by mass of the polyimide (A) is 50 to 150 parts by mass.
A photosensitive resin composition intended for patterning applications with organic solvent developers, where 95% or more of the components are organic solvents, and not for patterning applications with alkaline developers.
A film formation step in which a photosensitive resin film is formed using ,
An exposure step of exposing the photosensitive resin film,
A developing step in which the exposed photosensitive resin film is developed with an organic solvent developer in which 95% or more by mass of the components is an organic solvent,
A method for manufacturing electronic devices, including A method for manufacturing an electronic device according to claim 1,
Let IM be the number of moles of imide groups contained in the polyimide (A) mentioned above.
When AM is the number of moles of amide groups contained in the polyimide (A),
A method for manufacturing an electronic device, wherein the imidization rate, expressed as {IM/(IM+AM)} × 100 (%), is 90% or higher. A method for manufacturing an electronic device according to claim 1 or 2,
A method for manufacturing an electronic device, wherein the polyimide (A) has a structure represented by the following general formula (a).
In general formula (a),
X is a divalent organic group,
Y is a tetravalent organic group,
At least one of X and Y is a fluorine atom-containing group. A method for manufacturing an electronic device according to any one of claims 1 to 3,
The method for manufacturing an electronic device includes a polyimide (A) containing a fluorine atom. A method for manufacturing an electronic device according to any one of claims 1 to 4,
The polyimide (A) has an acid anhydride group at its terminal end, and the method for manufacturing an electronic device. A method for manufacturing an electronic device according to any one of claims 1 to 5,
The method for manufacturing an electronic device, wherein the polyimide (A) does not have a maleimide structure at its end. A method for manufacturing an electronic device according to any one of claims 1 to 6,
A method for manufacturing an electronic device, wherein the polyfunctional (meth)acrylate compound (B) comprises a (meth)acrylate compound (B1) with seven or more functions. A method for manufacturing an electronic device according to any one of claims 1 to 7,
A method for manufacturing an electronic device, wherein the amount of the polyfunctional (meth)acrylate compound (B) in the photosensitive resin composition is 70 to 120 parts by mass per 100 parts by mass of the polyimide (A). A method for manufacturing an electronic device according to any one of claims 1 to 8,
A method for manufacturing an electronic device, wherein the photosensitive agent (C) includes a photoradical generator. A method for manufacturing an electronic device according to any one of claims 1 to 9,
A method for manufacturing an electronic device, wherein the photosensitive resin composition further comprises a thermal radical initiator (D). A method for manufacturing an electronic device according to claim 10,
A method for manufacturing an electronic device, wherein the thermal radical initiator (D) contains an organic peroxide. A method for manufacturing an electronic device according to claim 10 or 11,
A method for manufacturing an electronic device, wherein the amount of the thermal radical initiator (D) in the photosensitive resin composition is 0.1 to 20 parts by mass per 100 parts by mass of the polyfunctional (meth)acrylate compound (B). A method for manufacturing an electronic device according to any one of claims 1 to 12,
A method for manufacturing an electronic device, wherein the photosensitive resin composition further comprises an epoxy resin (E). A method for manufacturing an electronic device according to claim 13,
A method for manufacturing an electronic device, wherein the photosensitive resin composition further comprises a curing catalyst (F) for the epoxy resin (E). A method for manufacturing an electronic device according to any one of claims 1 to 14,
A method for manufacturing an electronic device, wherein the photosensitive resin composition further comprises a silane coupling agent (G). A method for manufacturing an electronic device according to claim 15,
A method for manufacturing an electronic device, wherein the silane coupling agent (G) includes a silane coupling agent having a cyclic anhydride structure. A method for manufacturing an electronic device according to any one of claims 1 to 16,
A method for manufacturing an electronic device, wherein the photosensitive resin composition further comprises a surfactant (H). A method for manufacturing an electronic device according to any one of claims 1 to 17,
A method for manufacturing an electronic device, wherein the proportion of the polyimide (A) and the polyfunctional (meth)acrylate compound (B) in the entire photosensitive resin composition is 20 to 50% by mass. A method for manufacturing an electronic device according to any one of claims 1 to 18,
A method for manufacturing an electronic device, wherein the photosensitive resin composition is a varnish in which at least the polyimide (A) and the polyfunctional (meth)acrylate compound (B) are dissolved in the solvent (J). A method for manufacturing an electronic device according to any one of claims 1 to 19,
A method for manufacturing an electronic device, comprising a thermosetting step of heating and curing the exposed photosensitive resin film after the development step.