JP7501124B2 - Photosensitive resin composition having low dielectric properties, method for producing patterned cured product using the same, cured product of photosensitive resin composition having low dielectric properties, and electronic component - Google Patents

Description

The present disclosure relates to a photosensitive resin composition having low dielectric properties, a method for producing a patterned cured product using the same, and a cured product and electronic component in which the photosensitive resin composition having low dielectric properties is used for an interlayer insulating film, a cover coat layer or a surface protective film.

Conventionally, polyimide and polybenzoxazole, which have excellent heat resistance as well as electrical and mechanical properties, have been used for the surface protection film and interlayer insulating film of semiconductor elements. In recent years, photosensitive resin compositions in which these resins themselves are given photosensitivity have been used, and the use of these compositions can simplify the manufacturing process of patterned cured products and shorten the complicated manufacturing process (see, for example, Patent Document 1).
On the other hand, in order to increase the density and performance of semiconductor packages, a mounting form in which chips with different performance are mixed in one package has been proposed. In this case, a high-density interconnect technology between chips that is cost-effective is important (for example, see Patent Document 2).
Non-Patent Documents 1 and 2 describe a package-on-package (PoP) configuration in which a different package is connected by stacking it on a package using flip-chip mounting. This PoP configuration is widely adopted for smartphones, tablet terminals, and the like.

As other forms for mounting multiple chips at a high density, packaging technology using an organic substrate having high density wiring, fan-out type packaging technology (FO-WLP: Fan Out-Wafer Level Package) having a through mold via (TMV: Through Mold Via), packaging technology using a silicon or glass interposer, packaging technology using a through silicon via (TSV: Through Silicon Via), packaging technology using chips embedded in a substrate for inter-chip transmission, and the like have been proposed.
In particular, when semiconductor chips are mounted on one another in a semiconductor wiring layer and FO-WLP, a fine wiring layer is required to electrically connect the semiconductor chips with each other at a high density (for example, see Patent Document 3).
Furthermore, in recent years, with the emergence of not only smartphones but also wearable devices and the emergence of a system called "machine-to-machine communication" (M2M) in which devices communicate with each other without human intervention, mobile devices have become widespread in all areas of society, including transportation, medical care, companies, public facilities, schools, and homes. In order to cope with this increase in communication volume, efforts are being made to make mobile communication ultra-fast and expand the frequency bands available. In this context, there is an urgent need to transition to the next-generation communication standard called "5G." (See, for example, Non-Patent Document 3)
5G (5 Generation) is the fifth generation mobile communication system with new features such as ultra-high speed, multiple connections, and ultra-low latency. It enables communication between mobile terminals at speeds of over 10 Gbps, 100 times faster than the current fourth generation mobile communication system known as 4G.
To realize 5G, radio waves in a higher frequency band (first phase: up to 28 GHz, second phase: up to 100 GHz) than the current 4G (maximum frequency of about 3.5 GHz) will be used, so in order to deliver high-frequency radio waves with low power consumption and without degradation, low dielectric properties are now required for the materials that make up the antennas that transmit and receive radio waves (see, for example, Non-Patent Document 4).

JP 2009-265520 A JP 2012-529770 A US Patent Application Publication No. 2011/0221071

Jinseong Kim et al., "Application of Through Mold Via (TMV) as PoP Base Package", Electronic Components and Technology Conference (ECTC), p.1089-1092 (2008) S.W. Yoon et al., "Advanced Low Profile PoP Solution with Embedded Wafer Level PoP (eWLB-PoP) Technology", ECTC, p.1250-1254 (2012) International Media Service Institute: "5G Fifth Generation Mobile Communication System Latest Information", 2018 Urmy Ray, "Packaging and Integration Strategy for mm-Wave Products" Proceedings of iMAPS 2018(2018).

A wiring layer (semiconductor wiring layer) for mounting multiple semiconductor chips may be used in build-up substrates, wafer level packages (WLPs), fan-out type PoP bottom packages, etc. For example, polyimide resins and polybenzoxazole resins can be used for this wiring layer, but these resins generally have poor dielectric properties, and when used as materials for semiconductor packages related to 5G, problems such as signal degradation and delays occur.
On the other hand, it is known that polymers having an aromatic polyester skeleton exhibit liquid crystallinity like mesogenic skeletons and can achieve low dielectric properties. However, they have no photosensitivity (photoreactivity), and therefore a patterned cured product cannot be produced by the method described in the above-mentioned Patent Document 1.
In the present invention, by imparting photosensitivity to this aromatic polyester skeleton, it is possible to provide a resin that combines low dielectric properties with photolithography properties.
The present invention aims to provide a photosensitive resin composition having low dielectric properties that has good low dielectric properties, photolithography properties and insulation reliability, a method for producing a patterned cured product using the same, and a cured product using the photosensitive resin composition having low dielectric properties as an interlayer insulating film, a cover coat layer or a surface protective film.

The present invention relates to a resin composition used to form an insulating layer, comprising a resin having an aromatic polyesterimide structure represented by the following general formula (1), a photopolymerization initiator, and a thermal radical polymerization initiator, and when the resin having an aromatic polyesterimide structure represented by the general formula (1) does not contain a group represented by the following general formula (2), the resin composition further comprises a (meth)acryloyl compound, and is a photosensitive resin composition having low dielectric properties.

(In general formula (1), m is an integer of 1 to 100; Ar is a divalent group having an aromatic skeleton; R is a divalent group having an aromatic skeleton having 2 to 30 carbon atoms and 4 to 100 hydrogen atoms; -COOR ₁ and -COOR ₂ are each located at the ortho position relative to the adjacent -CONH-; and R ₁ , R ₂ and R' are each independently a hydrogen atom or a group represented by general formula (2), or a hydrocarbon group having 1 to 4 carbon atoms.)

(In general formula (2), R ₃ to R ₅ each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and n represents an integer of 1 to 10.)

The present invention also relates to [2] the photosensitive resin composition having low dielectric properties described in the above [1], further comprising a coupling agent.
The present invention also relates to [3] the photosensitive resin composition having low dielectric properties according to the above [1] or [2], further comprising a (meth)acryloyl compound.
The present invention also relates to [4] the photosensitive resin composition having low dielectric properties according to any one of [1] to [3] above, wherein a chloride ion concentration in a cured product of the photosensitive resin composition having low dielectric properties according to any one of [1] to [3] above is 5 ppm or less.
The present invention also relates to, [5] the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [4], wherein the breaking elongation of a cured product of the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [3] is 10 to 200%.
The present invention also relates to, [6] the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [5], wherein a dielectric constant at 10 GHz of a cured product of the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [3] is 3.2 or less.
The present invention also relates to, [7] the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [6], wherein the dielectric loss tangent at 10 GHz of a cured product of the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [3] is 0.0100 or less.
The present invention also relates to, [8] the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [7], wherein the 5% weight loss temperature of a cured product of the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [3] is 300° C. or higher.
The present invention also relates to, [9] the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [8], wherein a cured product of the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [3] has a moisture absorption rate of 1 mass% or less after being placed in an environment of 130°C and a relative humidity of 85% for 200 hours.
The present invention also relates to [10] a method for producing a patterned cured product, comprising the steps of: applying the photosensitive resin composition having low dielectric properties according to any one of the above [1] to [9] onto a substrate and drying to form a photosensitive resin film; patternwise exposing the photosensitive resin film to light to obtain a resin film; developing the resin film after the patternwise exposure using an organic solvent to obtain a patterned resin film; and heat-treating the patterned resin film.
The present invention also relates to [11] the method for producing a patterned cured product according to the above [10], wherein the heat treatment temperature is 200° C. or lower.
The present invention also relates to [12] a cured product obtained by curing the photosensitive resin composition having low dielectric properties according to any one of [1] to [9] above.
The present invention also relates to [13] the cured product according to the above [12], wherein the cured product is a patterned cured product.
The present invention also relates to [14] a cured product in which the cured product according to the above [12] or [13] is used as an interlayer insulating film, a cover coat layer, or a surface protective film.
The present invention also relates to [15] an electronic component comprising the interlayer insulating film, the cover coat layer or the surface protective film according to [14] above.

According to the present invention, it is possible to provide a resin composition that has low dielectric constant and low dielectric tangent, is photolithographically applicable, and forms an insulating layer with insulating reliability. This composition has low moisture absorption and can be heated at a low temperature, making it suitable for producing a patterned cured product. The cured product formed from this composition has low dielectric properties and low moisture absorption, and can be used to form highly reliable electronic components by applying it to an interlayer insulating film, a cover coat layer, or a surface protective film.

1 is a flow diagram of a method for producing a patterned cured product according to one embodiment of the present invention. 1A to 1C are diagrams illustrating a manufacturing process for an electronic component according to an embodiment of the present invention.

The following describes in detail the embodiments of the photosensitive resin composition having low dielectric properties, the method for producing a patterned cured product using the same, the cured product, the interlayer insulating film, the cover coat layer, the surface protective film, and the electronic component of the present invention. Note that the present invention is not limited to the following embodiments.
In this specification, "A or B" may include either A or B, or may include both. In addition, in this specification, the term "step" includes not only an independent step, but also a step that cannot be clearly distinguished from other steps, as long as the intended effect of the step is achieved.
A numerical range indicated using "to" indicates a range including the numerical values before and after "to" as the minimum and maximum values, respectively. Furthermore, in this specification, the content of each component in the composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified. Furthermore, unless otherwise specified, the exemplified materials may be used alone or in combination of two or more types.
In this specification, the term "(meth)acrylic group" means an "acrylic group" and a "methacrylic group".

(Resin containing an aromatic polyesterimide structure represented by general formula (1))
The photosensitive resin composition having low dielectric properties according to the present invention contains a resin (compound) containing an aromatic polyesterimide structure represented by the following general formula (1), a photopolymerization initiator, and a thermal radical polymerization initiator, and when the resin containing the aromatic polyesterimide structure of the general formula (1) does not contain a group represented by the following general formula (2), it further contains a (meth)acryloyl compound. That is, this resin composition is a photocurable (photosensitive) resin composition that is cured by light, or a thermosetting resin composition that is cured by heat. This resin composition is suitably used for forming an insulating layer such as an interlayer insulating film, a cover coat layer, or a surface protective film.

(In general formula (1), m is an integer of 1 to 100; Ar is a divalent group having an aromatic skeleton; R is a divalent group having an aromatic skeleton having 2 to 30 carbon atoms and 4 to 100 hydrogen atoms; -COOR ₁ and -COOR ₂ are each located at the ortho position relative to the adjacent -CONH-; and R ₁ , R ₂ and R' are each independently a hydrogen atom or a group represented by general formula (2), or a hydrocarbon group having 1 to 4 carbon atoms.)

(In general formula (2), R ₃ to R ₅ each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and n represents an integer of 1 to 10.)
The aromatic skeleton of the divalent group having an aromatic skeleton of Ar corresponds to Ar of the ester group-containing tetracarboxylic acid dianhydride represented by the general formula (3) described later, which is used when synthesizing a resin containing an aromatic polyesterimide structure, and indicates an aromatic corresponding to the aromatic diol among trimellitic anhydride chloride and aromatic diol, which are raw materials for synthesizing this ester group-containing tetracarboxylic acid dianhydride. The aromatic skeleton is a benzene skeleton, a naphthalene skeleton, a pyridine skeleton, etc., and is a divalent group that may have a hydrogen atom, an alkyl group, an alkoxy group, a halogen, or other substituent. Specifically, it is a phenylene group or a naphthalene group, and can be bonded to the aromatic skeleton by a bridging group (-O-, -S-, -(CO)-, -O-(CO)-, or -(CO)-O-, etc.) from the aromatic skeleton. It indicates a residue obtained by removing the diol from the aromatic diol described later.
The divalent group having an aromatic skeleton of 2 to 30 carbon atoms and 4 to 100 hydrogen atoms represented by R is a diamine residue obtained by removing an amino group from an aromatic diamine compound described below that is used in synthesizing a resin containing an aromatic polyesterimide structure. Specifically, it is a phenylene group or a naphthalene group, and it can also be bonded to the aromatic skeleton via a crosslinking group (-O-, -S-, -(CO)-, -O-(CO)-, -(CO)-O-, etc.) from the aromatic skeleton.
The hydrocarbon group having 1 to 4 carbon atoms is, for example, a methyl, ethyl, propyl or butyl group.
The aliphatic hydrocarbon group having 1 to 3 carbon atoms is, for example, a methyl, ethyl or propyl group.

The resin containing an aromatic polyesterimide structure represented by general formula (1) is obtained by reacting an ester group-containing tetracarboxylic acid dianhydride represented by the following general formula (3) with an aromatic diamine compound. To ensure photocurability, a methacryloyl group may be introduced into the carboxylic acid generated by ring-opening of the acid dianhydride. In this case, at least one of R ₁ , R ₂ , and R′ in general formula (1) is a group represented by general formula (2).

(In general formula (3), Ar is a divalent group having an aromatic skeleton.)
An example of an ester group-containing tetracarboxylic acid dianhydride is bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-1,4-phenylene (p-phenylenebis(trimellitate anhydride), product name: TAHQ, manufactured by Manac Corporation). Alternatively, a product produced by reacting trimellitic anhydride chloride with an aromatic diol may be used.

Examples of aromatic diols include hydroquinone, methylhydroquinone, 2,3-dimethylhydroquinone, trimethylhydroquinone, tetramethylhydroquinone, methoxyhydroquinone, 1,4-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl ether, 1,4-bis(4-hydroxyphenoxy)benzene, 4,4'-dihydroxydiphenylmethane, 2,2'-bis(4-hydroxyphenyl)propane, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5- Examples of such compounds include methylresorcinol and 1,4-bis(3-hydroxyphenoxy)benzene. In terms of low dielectric properties, heat resistance, and availability, 1,4-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylmethane, 2,2'-bis(4-hydroxyphenyl)propane, and 1,4-bis(3-hydroxyphenoxy)benzene are preferred. In terms of low moisture absorption and linearity of the molecules, 1,4-dihydroxynaphthalene, 4,4'-dihydroxydiphenylmethane, and 2,2'-bis(4-hydroxyphenyl)propane are particularly preferred. These compounds may be used alone or in combination of two or more.

When reacting trimellitic anhydride chloride with an aromatic diol, the reaction ratio is preferably 2.0 to 3.0 moles of trimellitic anhydride chloride for every 1 mole of aromatic diol. By using 2 moles or more of trimellitic anhydride chloride, the trimellitic anhydride chloride and aromatic diol can be reacted sufficiently, and by using 3.0 moles or less, the reaction is prevented from becoming too violent, allowing for stable synthesis.

The reaction for synthesizing tetracarboxylic dianhydride may be carried out in an organic solvent. Examples of organic solvents include aprotic solvents such as tetrahydrofuran (THF), N-methylpyrrolidone (NMP), equamide-based solvents (KJCMPA-100, KJCBPA-100; both are product names of KJ Chemicals Co., Ltd.), pyridine, γ-butyrolactone, dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), 1,4-dioxane, picoline, acetone, chloroform, toluene, xylene, dichloromethane, chloroform, 1,2-dichloroethane, N,N-diethylacetamide, hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone, and 1,2-dimethoxyethane-bis(2-methoxyethyl)ether, and protic solvents such as phenol, o-cresol, m-cresol, p-cresol, o-chlorophenol, m-chlorophenol, and p-chlorophenol. Among these, from the viewpoint of the solubility of the raw materials, tetrahydrofuran (THF), N-methylpyrrolidone (NMP), KJCMPA-100, KJCBPA-100, dimethylacetamide (DMAc), dimethylformamide (DMF), and dimethylsulfoxide (DMSO) are preferred, and from the viewpoint of lower toxicity, tetrahydrofuran (THF), N-methylpyrrolidone (NMP), KJCMPA-100, and KJCBPA-100 are particularly preferred. It is preferable to use these solvents dehydrated, for example, with molecular sieves. These may be used alone or in a mixture of two or more.

The concentration during synthesis is preferably 1 to 50% by mass, and 5 to 30% by mass is preferable in terms of reducing reaction time and waste solvent (low environmental impact). If the solute concentration is high, the reaction temperature will be 50°C or higher, and there is a possibility of a decrease in yield due to side reactions. If the internal temperature exceeds 50°C, it is preferable to cool it by a method such as water cooling.

Examples of the aromatic diamine include 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 3-methyl-1,4-diaminobenzene, 2,5-dimethyl-1,4-diaminobenzene, 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyl-diphenylmethane, 4,4'-diamino-3,3'-diethyl-diphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,3- Bis(4-aminophenoxy)benzene, 4,4'-diamino-3,3'-dimethoxybiphenyl (o-dianisidine), 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-2,2'-dimethoxybiphenyl, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ketone, benzidine, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy) Examples of the benzene include 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 2,2-bis(4-(4-amino-2-(trifluoromethyl)phenoxy)phenyl)hexafluoropropane, N-(4-aminophenyl)-4-aminobenzamide, and 4-aminophenyl-4-aminobenzoate. These may be used alone or in combination of two or more.
Among these, from the viewpoints of low dielectric properties and heat resistance, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diamino-3,3'-dimethoxybiphenyl (o-dianisidine), 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 2,2-bis(4-(4-amino-2-(trifluoromethyl)phenoxy)phenyl)hexafluoropropane, N-(4-aminophenyl)-4-aminobenzamide, and 4-aminophenyl-4-aminobenzoate are preferred, and from the viewpoint of low toxicity, 4,4'-diaminodiphenyl ether, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, N-(4-aminophenyl)-4-aminobenzamide, and 4-aminophenyl-4-aminobenzoate are particularly preferred.

When synthesizing a polyesterimide precursor of a resin containing an aromatic polyesterimide structure represented by general formula (1), when the aforementioned tetracarboxylic dianhydride is 1.0 mol, the ratio of aromatic diamine is preferably 0.7 to 0.99 mol, and from the viewpoint of solvent solubility, etc., it is particularly preferable to set it to 0.85 to 0.97 mol.

The reaction for synthesizing the polyesterimide precursor may be carried out in an organic solvent. Examples of the organic solvent include aprotic solvents such as tetrahydrofuran (THF), N-methylpyrrolidone (NMP), equamide-based solvents (KJCMPA-100, KJCBPA-100; both are product names of KJ Chemicals Co., Ltd.), pyridine, γ-butyrolactone, dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), 1,4-dioxane, picoline, acetone, chloroform, toluene, xylene, dichloromethane, chloroform, 1,2-dichloroethane, N,N-diethylacetamide, hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone, and 1,2-dimethoxyethane-bis(2-methoxyethyl)ether, and protic solvents such as phenol, o-cresol, m-cresol, p-cresol, o-chlorophenol, m-chlorophenol, and p-chlorophenol. Among these, from the viewpoint of the solubility of the raw materials, tetrahydrofuran (THF), N-methylpyrrolidone (NMP), KJCMPA-100, KJCBPA-100, dimethylacetamide (DMAc), dimethylformamide (DMF), and dimethylsulfoxide (DMSO) are preferred, and from the viewpoint of lower toxicity and higher boiling point, gamma-butyrolactone, N-methylpyrrolidone (NMP), KJCMPA-100, and KJCBPA-100 are particularly preferred. These solvents are preferably dehydrated, for example, with molecular sieves. These may be used alone or in a mixture of two or more.

The concentration during synthesis is preferably 10 to 50% by mass, and from the viewpoint of reducing reaction time and waste solvent (low environmental impact), 15 to 40% by mass is preferred. If the concentration of the solute is high, the reaction temperature will be 50°C or higher, and there is a possibility of a decrease in yield due to side reactions. If the internal temperature exceeds 50°C, it is preferable to cool the solution using a method such as water cooling. From the viewpoint of handling, the viscosity of the polyesterimide precursor solution is preferably 0.1 to 20.0 dL/g, and particularly preferably 0.5 to 10.0 dL/g.

After synthesizing the polyesterimide precursor, the acid anhydride is opened to produce a carboxylic acid, which can then be esterified with, for example, 2-hydroxyethyl methacrylate (HEMA) to introduce a methacryloyl group. This can impart photocuring properties to the polyimide polymer, allowing the polymer to have both lithographic properties and low dielectric properties.

(Photopolymerization initiator)
The present invention may contain a radical polymerization initiator. Radical polymerization initiators include those that are activated by light or heat, and examples of photoradical polymerization initiators (photopolymerization initiators) include benzophenone, o-benzoyl methyl benzoate, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, fluorenone and other benzophenone derivatives, 2,2'-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexylphenyl ketone and other acetophenone derivatives, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, diethylthioxanthone and other thioxanthone derivatives, benzil, benzil dimethyl ketal, benzil-β-methoxyethyl acetal and other benzyl derivatives, benzoin, benzoin methyl ether and other benzoin derivatives, and and 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-benzoyl)oxime, 1,3-diphenylpropanetrione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime), and oxime esters such as the compound represented by the following formula (4) are preferably mentioned, but are not limited thereto. The photopolymerization initiator may be used alone or in combination of two or more kinds.
In particular, oxime esters are preferred in terms of high sensitivity.

The content of the photopolymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the resin containing the aromatic polyesterimide structure of general formula (1).
Within the above range, photocrosslinking tends to be uniform in the thickness direction, making it easier to obtain a substantial relief pattern.

(Thermal Radical Polymerization Initiator)
The thermal radical polymerization initiator is preferably a compound that does not decompose when heated (dried) to remove the solvent during film formation, but decomposes when heated during curing to generate radicals and promote the polymerization reaction.
As the thermal radical polymerization initiator, for example, a compound having a decomposition temperature of 110° C. or more and 200° C. or less is preferable, and from the viewpoint of promoting the polymerization reaction at a lower temperature, a compound having a decomposition temperature of 110° C. or more and 175° C. or less is more preferable.
Specific examples include ketone peroxides such as methyl ethyl ketone peroxide, peroxyketals such as 1,1-di(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-hexylperoxy)cyclohexane, and 1,1-di(t-butylperoxy)cyclohexane, hydroperoxides such as 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and p-methane hydroperoxide, dialkyl peroxides such as dicumyl peroxide and di-t-butyl peroxide, and dilauroys. Examples of peroxyesters include 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, bis(1-phenyl-1-methylethyl)peroxide, etc. Examples of commercially available peroxyesters include those sold under the trade names "Percumyl D", "Percumyl P", and "Percumyl H" (all manufactured by NOF Corporation).

The content of the thermal radical polymerization initiator is preferably 0.1 to 20 parts by mass relative to 100 parts by mass of the resin containing the aromatic polyesterimide structure of general formula (1), more preferably 0.2 to 20 parts by mass to ensure good flux resistance, and even more preferably 0.3 to 10 parts by mass from the viewpoint of suppressing a decrease in solubility due to decomposition during drying.

(Coupling Agent)
The photosensitive resin composition having low dielectric properties of the present invention may also contain a coupling agent. The coupling agent may be, for example, a silane coupling agent. The silane coupling agent may have, for example, a vinyl group, an epoxy group, a styryl group, an acryloyl group, a methacryloyl group, an amino group, a ureido group, an isocyanate group, an isocyanurate group, a mercapto group, or the like.

Examples of the silane coupling agent having a vinyl group include KBM-1003 and KBE-1003 (both trade names, manufactured by Shin-Etsu Chemical Co., Ltd.; the same applies below).
Examples of silane coupling agents having an epoxy group include KBM-303, 402, 403, KBE-402, 403, X-12-981S, and X-12-984S.
An example of a silane coupling agent having a styryl group is KBM-1403.
Examples of silane coupling agents having a methacryloyl group include KBM-502, 503, KBE-502, 503, and the like.
Examples of silane coupling agents having an acryloyl group include KBM-5103, X-12-1048, and X-12-1050.
Examples of silane coupling agents having an amino group include KBM-602, 603, 903, 573, 575, KBE-903, 9103P, and X-12-972F.
An example of a silane coupling agent having a ureido group is KBE-585.
Examples of silane coupling agents having an isocyanate group include KBE-9007 and X-12-1159L.
An example of a silane coupling agent having an isocyanurate group is KBM-9659.
Examples of silane coupling agents having a mercapto group include KBM-802, 803, X-12-1154, and X-12-1156.
Among these, KBM-303, 402, 403, KBE-402, 403, X-12-981S, and X-12-984S having an epoxy group are preferred in that they can react with a carboxy group to improve adhesion, and KBM-502, 503, KBE-502, and 503 having a methacryloyl group, KBM-5103, X-12-1048, and X-12-1050 having an acryloyl group, and KBM-602, 603, 903, 573, 575, KBE-903, 9103P, and X-12-972F having an amino group are preferred in that they can react with an esterified methacryloyl group.
Among these, KBM-502, 503, KBE-502, 503, and KBM-5103 are particularly preferred from the viewpoint of storage stability. These may be used alone or in combination of two or more types depending on the purpose, application, etc.

The content of the silane coupling agent is preferably 0.01 to 5 parts by mass per 100 parts by mass of the resin composition in order to improve adhesion to glass, silica, etc., and more preferably 0.1 to 2 parts by mass in order to further reduce the amount of unreacted material remaining.

((Meth)acryloyl compounds)
The photosensitive resin composition having low dielectric properties of the present invention contains a (meth)acryloyl compound when the resin containing the aromatic polyesterimide structure of the general formula (1) does not contain a group represented by the general formula (2). Also, even when the resin containing the aromatic polyesterimide structure of the general formula (1) contains a group represented by the general formula (2), the photosensitive resin composition may contain a (meth)acryloyl compound.
Examples of the (meth)acryloyl compound include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, trimethylolpropane dimethacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol Examples of the acrylates include aryl hexaacrylate, dipentaerythritol hexamethacrylate, styrene, divinylbenzene, 4-vinyltoluene, 4-vinylpyridine, N-vinylpyrrolidone, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 1,3-acryloyloxy-2-hydroxypropane, 1,2-methacryloyloxy-2-hydroxypropane, methylenebisacrylamide, N,N-dimethylacrylamide, N-methylolacrylamide, triacrylate of tris(β-hydroxyethyl)isocyanurate, a compound represented by the following general formula (5), urethane acrylate or urethane methacrylate, urea acrylate, isocyanuric acid-modified di/triacrylate and methacrylate, tricyclodecane dimethanol diacrylate (A-DCP), and tricyclodecane dimethanol methacrylate (DCP).

In formula (5), R ⁴¹ and R ⁴² each independently represent a hydrogen atom or a methyl group, and f and g each independently represent an integer of 1 or more.

Among these, tricyclodecane dimethanol diacrylate (A-DCP) and tricyclodecane dimethanol methacrylate (DCP) are preferred because they have good compatibility with resins containing the aromatic polyesterimide structure of general formula (1) and have excellent low dielectric properties.

The content of the (meth)acryloyl compound is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the resin containing the aromatic polyesterimide structure of general formula (1), and is particularly preferably 0.5 to 20 parts by mass in order to achieve both lithography properties and heat resistance.

(Other ingredients)
In addition to the above, the photosensitive resin composition used in the present invention may further contain components such as a dissolution promoter, a dissolution inhibitor, a pigment, a dye, a surfactant, or a leveling agent. A solvent can be used to dissolve or disperse the above components.

(Method for producing a patterned cured product)
The cured product of the present invention can be obtained by curing the above-mentioned photosensitive resin composition having low dielectric properties.
The cured product of the present invention may be used as a patterned cured product or as a non-patterned cured product.
The film thickness of the cured product of the present invention is preferably 5 to 20 μm. The method for producing a patterned cured product of the present invention includes the steps of applying the above-mentioned photosensitive resin composition onto a substrate and drying to form a photosensitive resin film, exposing the photosensitive resin film to a pattern to obtain a resin film, developing the resin film after the pattern exposure using an organic solvent to obtain a patterned resin film, and heat-treating the patterned resin film (see FIG. 1).
This makes it possible to obtain a patterned cured product.

The method for producing a patternless cured product includes, for example, the steps of forming the above-mentioned photosensitive resin film and performing a heat treatment. It may further include a step of exposing the material to light.

Examples of the substrate include semiconductor substrates such as glass substrates and Si substrates (silicon wafers), metal oxide insulator substrates such as _TiO2 substrates and _SiO2 substrates, silicon nitride substrates, copper substrates, and copper alloy substrates.

The coating method is not particularly limited, and can be carried out using a spinner, etc. Drying can be carried out using a hot plate, an oven, etc.
The drying temperature is preferably 90 to 150° C., and from the viewpoint of ensuring the dissolution contrast, more preferably 90 to 120° C. The drying time is preferably 30 seconds to 5 minutes. Drying may be carried out two or more times. Thereby, a photosensitive resin film in which the above-mentioned photosensitive resin composition is formed into a film shape can be obtained.

The thickness of the photosensitive resin film is preferably 5 to 100 μm, more preferably 5 to 50 μm, and even more preferably 5 to 20 μm.

The pattern exposure is performed by exposing a predetermined pattern through a photomask, for example.
The actinic rays to be irradiated include i-rays, broadband (BB) ultraviolet rays, visible light, and radiation, and the like, with i-rays being preferred.
As the exposure device, a parallel exposure device, a projection exposure device, a stepper, a scanner exposure device, or the like can be used.

By developing, a resin film having a pattern formed thereon (patterned resin film) can be obtained. In general, when a negative type photosensitive resin composition is used, the unexposed areas are removed with a developer.
The organic solvent used as the developer may be a good solvent for the photosensitive resin film, either alone or in the form of a suitable mixture of a good solvent and a poor solvent.
Examples of the good solvent include N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, gamma-butyrolactone, α-acetyl-gamma-butyrolactone, cyclopentanone, and cyclohexanone.
Examples of the poor solvent include toluene, xylene, methanol, ethanol, isopropanol, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and water.

A surfactant may be added to the developer. The amount of surfactant added is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, per 100 parts by weight of the developer. The development time can be, for example, twice the time it takes for the photosensitive resin film to be immersed and completely dissolved. The development time varies depending on the components used, but is preferably 10 seconds to 15 minutes, more preferably 10 seconds to 5 minutes, and even more preferably 20 seconds to 5 minutes from the viewpoint of productivity.

After development, the substrate may be washed with a rinse solution. As the rinse solution, distilled water, methanol, ethanol, isopropanol, toluene, xylene, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, etc. may be used alone or in appropriate mixtures, or in stepwise combinations.

A patterned cured product can be obtained by heat-treating the patterned resin film. The heat treatment temperature is preferably 250° C. or less, more preferably 120 to 250° C., and even more preferably 200° C. or less or 140 to 200° C.
By keeping the content within the above range, damage to the substrate and devices can be minimized, devices can be produced with a high yield, and energy savings can be achieved in the process.

The heat treatment time is preferably 5 hours or less, and more preferably 3 minutes to 3 hours.
The atmosphere for the heat treatment may be air or an inert atmosphere such as nitrogen, but a nitrogen atmosphere is preferred from the viewpoint of preventing oxidation of the patterned resin film. Examples of the apparatus used for the heat treatment include a quartz tube furnace, a hot plate, a rapid thermal annealer, a vertical diffusion furnace, an infrared curing furnace, an electron beam curing furnace, and a microwave curing furnace.

The cured product of the present invention can be used as a passivation film, a buffer coat film, an interlayer insulating film, a cover coat layer, a surface protective film, or the like.
Using one or more selected from the group consisting of the above passivation films, buffer coat films, interlayer insulating films, cover coat layers, and surface protection films, etc., highly reliable electronic components such as semiconductor devices, multilayer wiring boards, various electronic devices, and stacked devices (multi-die fan-out wafer level packages, etc.) can be manufactured.

The chloride ion concentration in the cured product of the low dielectric photosensitive resin composition of the present invention is preferably 5 ppm or less. When the chloride ion concentration is 5 ppm or less, electrolytic corrosion can be prevented in semiconductor devices of electronic components, and moisture resistance is improved.
Furthermore, it is preferable that the breaking elongation of the cured product is 10 to 200%, which can reduce stress in electronic components and improve their reliability.
Furthermore, if the cured product has a dielectric constant of 3.2 or less and a dielectric loss tangent of 0.0100 or less at 10 GHz, it has excellent low dielectric properties and can reduce dielectric loss and transmission loss even in high frequency regions such as 5 GHz.
Furthermore, if the 5% weight loss temperature of the cured product is 300°C or higher, the product has excellent heat resistance, and if the moisture absorption rate after being placed in an environment of 130°C and a relative humidity of 85% for 200 hours is 1 mass% or less, the product has low moisture absorption and improves electrical and mechanical properties.
Furthermore, if the heat treatment temperature is 200° C. or less, damage to the substrate and devices can be minimized, and devices can be produced with a high yield.

(Electronic Components)
An example of a manufacturing process for a semiconductor device, which is an electronic component of the present invention, will be described with reference to the drawings.
FIG. 2 is a manufacturing process diagram of a semiconductor device having a multi-layer wiring structure, which is an electronic component according to one embodiment of the present invention.
2, a semiconductor substrate 1 such as a Si substrate having circuit elements is covered with a protective film 2 such as a silicon oxide film except for a predetermined portion of the circuit elements, and a first conductor layer 3 is formed on the exposed circuit elements. Then, an interlayer insulating film 4 is formed on the semiconductor substrate 1.

Next, a photosensitive resin layer 5, such as a chlorinated rubber or phenol novolac type, is formed on the interlayer insulating film 4, and a window 6A is provided by known photoetching techniques so that a predetermined portion of the interlayer insulating film 4 is exposed.

The interlayer insulating film 4 from which the window 6A is exposed is selectively etched to provide a window 6B.
Next, the photosensitive resin layer 5 is completely removed using an etching solution that corrodes only the photosensitive resin layer 5 without corroding the first conductor layer 3 exposed from the window 6B.

Further, a second conductor layer 7 is formed by using a known photolithography technique, and is electrically connected to the first conductor layer 3 .
When forming a multi-layer wiring structure having three or more layers, the above steps can be repeated to form each layer.

Next, the above-mentioned photosensitive resin composition is used to open windows 6C by pattern exposure to form a surface protective film 8. The surface protective film 8 protects the second conductor layer 7 from external stress, α-rays, etc., and the resulting semiconductor device has excellent reliability.
In the above example, the interlayer insulating film can also be formed using the photosensitive resin composition of the present invention.

The present invention will be described in more detail below with reference to examples and comparative examples. Note that the present invention is not limited to the following examples.

The components used in the examples of the present invention are as follows.
1. Acid anhydride [1] p-phenylene bis(trimellitate anhydride) (TAHQ, product name manufactured by Manac Corporation)
[2] Acid anhydride (1) (self-synthesized, Production Example 1 below)
[3] Acid anhydride (2) (self-synthesized, Production Example 2 below)
[4] Acid anhydride (3) (self-synthesis, Production Example 3 below)
[5] Pyromellitic anhydride [6] 1,6-(hexamethylene)bis(trimellitate anhydride)

2. Aromatic diols [1] 1,4-dihydroxynaphthalene [2] 4,4'-dihydroxydiphenylmethane [3] 2,2'-bis(4-hydroxyphenyl)propane

3. Aromatic diamines [1] p-phenylenediamine [2] 4,4'-diaminodiphenyl ether [3] 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl [4] 4-aminophenyl-4-aminobenzoate [5] 4,4'-diamino-2,2'-dimethylbiphenyl

4. Coupling Agent [1] KBM-503 (3-methacryloxypropyltrimethoxysilane, product name, manufactured by Shin-Etsu Chemical Co., Ltd.)

5. (Meth)acryloyl compound [1] Tricyclodecane dimethanol diacrylate (A-DCP, product name manufactured by Shin-Nakamura Chemical Co., Ltd.)

6. Photopolymerization initiators and thermal radical polymerization initiators [1] Dicumyl peroxide (Percumyl D, product name, manufactured by NOF Corporation)
[2] 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazoyl-3-yl]ethanone-1-(O-acetyloxime) (OXE02, product name manufactured by BASF)
7. Solvent [1] NMP (N-methyl-2-pyrrolidone)

According to the following Production Examples 1 to 22, aromatic polyester precursors (1) to (16) and aromatic polyimides (1) to (3) were synthesized and used in the Examples.
Then, using the resin synthesized above, "OXE02" as a photopolymerization initiator, and "Percumyl D" as a thermal radical polymerization initiator, the resin compositions of Examples 1 to 16 and Comparative Examples 1 to 6 shown in Tables 1 to 3 below were prepared and subjected to testing.

(Production Example 1)
<Synthesis of acid anhydride (1)>
The aromatic ester skeleton-containing tetracarboxylic acid dianhydride represented by formula (6) (referred to as acid anhydride (1)) was synthesized as follows.

In a recovery flask, trimellitic anhydride chloride (48 mmol) was dissolved in dehydrated tetrahydrofuran (THF) (45.5 mL) and sealed with a septum cap to prepare solution A. In a separate flask, 1,4-dihydroxynaphthalene (20 mmol) was dissolved in THF (68.5 mL), and pyridine (120 mmol) was added thereto and sealed with a septum cap to prepare solution B.
While cooling and stirring in an ice bath, solution B was slowly dropped into solution A using a syringe, and then stirred at room temperature (25°C) for 12 hours. After the reaction was completed, the white precipitate (pyridine hydrochloride) was filtered off, and the filtrate was concentrated using an evaporator, and then dropped into water to deposit a precipitate, which was repeatedly washed with water and dried in vacuum at 160°C for 12 hours to obtain a yellow powdery crude product. This was recrystallized with acetic anhydride, washed with acetic anhydride and toluene, and dried in vacuum at 160°C for 12 hours to obtain acid anhydride (1) as a yellow crystal.

(Production Example 2)
<Synthesis of acid anhydride (2)>
The aromatic ester skeleton-containing tetracarboxylic acid dianhydride represented by formula (7) (referred to as acid anhydride (2)) was synthesized as follows.

In a recovery flask, trimellitic anhydride chloride (48 mmol) was dissolved in dehydrated tetrahydrofuran (THF) (45.5 mL) and sealed with a septum cap to prepare solution A. In a separate flask, 4,4'-dihydroxydiphenylmethane (20 mmol) was dissolved in THF (68.5 mL), and pyridine (120 mmol) was added thereto and sealed with a septum cap to prepare solution B.
While cooling and stirring in an ice bath, solution B was slowly dropped into solution A using a syringe, and then stirred at room temperature for 12 hours. After the reaction was completed, the white precipitate (pyridine hydrochloride) was filtered off, and the filtrate was concentrated using an evaporator, and then dropped into water to deposit a precipitate, which was repeatedly washed with water and vacuum dried at 160°C for 12 hours to obtain a yellow powdery crude product. This was recrystallized with acetic anhydride, washed with acetic anhydride and toluene, and vacuum dried at 160°C for 12 hours to obtain acid anhydride (2) as yellow crystals.

(Production Example 3)
<Synthesis of acid anhydride (3)>
The aromatic ester skeleton-containing tetracarboxylic acid dianhydride represented by formula (8) (referred to as acid anhydride (3)) was synthesized as follows.

In a recovery flask, trimellitic anhydride chloride (48 mmol) was dissolved in dehydrated tetrahydrofuran (THF) (45.5 mL) and sealed with a septum cap to prepare solution A. In a separate flask, 2,2'-bis(4-hydroxyphenyl)propane (20 mmol) was dissolved in THF (68.5 mL), pyridine (120 mmol) was added thereto, and the flask was sealed with a septum cap to prepare solution B.
While cooling and stirring in an ice bath, solution B was slowly dropped into solution A using a syringe, and then stirred at room temperature for 12 hours. After the reaction was completed, the white precipitate (pyridine hydrochloride) was filtered off, and the filtrate was concentrated using an evaporator, and then dropped into water to deposit a precipitate, which was repeatedly washed with water and vacuum dried at 160°C for 12 hours to obtain a yellow powdery crude product. This was recrystallized with acetic anhydride, washed with acetic anhydride and toluene, and vacuum dried at 160°C for 12 hours to obtain a yellow crystalline acid anhydride (3).

(Production Example 4)
<Synthesis of aromatic polyesterimide precursor (1)>
p-Phenylenediamine (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, p-phenylenebis(trimellitate anhydride) (TAHQ, 5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic esterimide precursor (1). (The non-volatile content of the varnish was 25% by mass)

(Production Example 5)
<Synthesis of aromatic polyesterimide precursor (2)>
To the solution of aromatic polyesterimide precursor (1) prepared above, trifluoroacetic anhydride (9.87 mol) was added under water cooling, the mixture was stirred at 45°C for 3 hours, and 2-hydroxyethyl methacrylate (HEMA) (7.4 mol) was added. This reaction solution was dropped into distilled water, and the precipitate was collected by filtration and dried under reduced pressure. The obtained powder was dissolved in ultra-dehydrated NMP to obtain a solution of aromatic polyesterimide precursor (2) (non-volatile content 25% by mass).

(Production Example 6)
<Synthesis of aromatic polyesterimide precursor (3)>
4,4'-Diaminodiphenyl ether (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, p-phenylene bis(trimellitate anhydride) (TAHQ, 5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic ester imide precursor (3). (The non-volatile content of the varnish was 25% by mass)

(Production Example 7)
<Synthesis of aromatic polyesterimide precursor (4)>
To the solution of aromatic polyesterimide precursor (3) prepared above, trifluoroacetic anhydride (9.87 mol) was added under water cooling, the mixture was stirred at 45°C for 3 hours, and 2-hydroxyethyl methacrylate (HEMA) (7.4 mol) was added. This reaction solution was dropped into distilled water, and the precipitate was collected by filtration and dried under reduced pressure. The obtained powder was dissolved in ultra-dehydrated NMP to obtain a solution of aromatic polyesterimide precursor (4) (non-volatile content 25% by mass).

(Production Example 8)
<Synthesis of aromatic polyesterimide precursor (5)>
4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, p-phenylenebis(trimellitate anhydride) (TAHQ, 5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic esterimide precursor (5). (The non-volatile content of the varnish was 25% by mass)

(Production Example 9)
<Synthesis of aromatic polyesterimide precursor (6)>
To the solution of aromatic polyesterimide precursor (5) prepared above, trifluoroacetic anhydride (9.87 mol) was added under water cooling, the mixture was stirred at 45°C for 3 hours, and 2-hydroxyethyl methacrylate (HEMA) (7.4 mol) was added. This reaction solution was dropped into distilled water, and the precipitate was collected by filtration and dried under reduced pressure. The obtained powder was dissolved in ultra-dehydrated NMP to obtain a solution of aromatic polyesterimide precursor (6) (non-volatile content 25% by mass).

(Production Example 10)
<Synthesis of aromatic polyesterimide precursor (7)>
4-Aminophenyl-4-aminobenzoate (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, p-phenylenebis(trimellitate anhydride) (TAHQ, 5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic ester imide precursor (7). (The non-volatile content of the varnish was 25% by mass)

(Production Example 11)
<Synthesis of aromatic polyesterimide precursor (8)>
To the solution of aromatic polyesterimide precursor (7) prepared above, trifluoroacetic anhydride (9.87 mol) was added under water cooling, the mixture was stirred at 45°C for 3 hours, and 2-hydroxyethyl methacrylate (HEMA) (7.4 mol) was added. This reaction solution was dropped into distilled water, and the precipitate was collected by filtration and dried under reduced pressure. The obtained powder was dissolved in ultra-dehydrated NMP to obtain a solution of aromatic polyesterimide precursor (8) (non-volatile content 25% by mass).

(Production Example 12)
<Synthesis of aromatic polyesterimide precursor (9)>
4,4'-Diamino-2,2'-dimethylbiphenyl (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, p-phenylenebis(trimellitate anhydride) (TAHQ, 5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic esterimide precursor (9). (The non-volatile content of the varnish was 25% by mass)

(Production Example 13)
<Synthesis of aromatic polyesterimide precursor (10)>
To the solution of aromatic polyesterimide precursor (9) prepared above, trifluoroacetic anhydride (9.87 mol) was added under water cooling, the mixture was stirred at 45°C for 3 hours, and 2-hydroxyethyl methacrylate (HEMA) (7.4 mol) was added. This reaction solution was dropped into distilled water, and the precipitate was collected by filtration and dried under reduced pressure. The obtained powder was dissolved in ultra-dehydrated NMP to obtain a solution of aromatic polyesterimide precursor (10) (non-volatile content 25% by mass).

(Production Example 14)
<Synthesis of aromatic polyesterimide precursor (11)>
p-Phenylenediamine (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, acid anhydride (1) (5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic ester imide precursor (11). (The non-volatile content of the varnish was 25% by mass)

(Production Example 15)
<Synthesis of aromatic polyesterimide precursor (12)>
To the solution of aromatic polyesterimide precursor (11) prepared above, trifluoroacetic anhydride (9.87 mol) was added under water cooling, the mixture was stirred at 45°C for 3 hours, and 2-hydroxyethyl methacrylate (HEMA) (7.4 mol) was added. This reaction solution was dropped into distilled water, and the precipitate was collected by filtration and dried under reduced pressure. The obtained powder was dissolved in ultra-dehydrated NMP to obtain a solution of aromatic polyesterimide precursor (12) (non-volatile content 25% by mass).

(Production Example 16)
<Synthesis of aromatic polyesterimide precursor (13)>
p-Phenylenediamine (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, acid anhydride (2) (5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic ester imide precursor (13). (The non-volatile content of the varnish was 25% by mass)

(Production Example 17)
<Synthesis of aromatic polyesterimide precursor (14)>
To the solution of aromatic polyesterimide precursor (13) prepared above, trifluoroacetic anhydride (9.87 mol) was added under water cooling, the mixture was stirred at 45°C for 3 hours, and 2-hydroxyethyl methacrylate (HEMA) (7.4 mol) was added. This reaction solution was dropped into distilled water, and the precipitate was collected by filtration and dried under reduced pressure. The obtained powder was dissolved in ultra-dehydrated NMP to obtain a solution of aromatic polyesterimide precursor (14) (non-volatile content 25% by mass).

(Production Example 18)
<Synthesis of aromatic polyesterimide precursor (15)>
p-Phenylenediamine (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, acid anhydride (3) (5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic ester imide precursor (15). (The non-volatile content of the varnish was 25% by mass)

(Production Example 19)
<Synthesis of aromatic polyesterimide precursor (16)>
Trifluoroacetic anhydride (9.87 mol) was added to the solution of aromatic polyesterimide precursor (15) prepared above under water cooling, and the mixture was stirred at 45°C for 3 hours, followed by the addition of 2-hydroxyethyl methacrylate (HEMA) (7.4 mol). This reaction solution was dropped into distilled water, and the precipitate was collected by filtration and dried under reduced pressure. The resulting powder was dissolved in ultra-dehydrated NMP to obtain a solution of aromatic polyesterimide precursor (16) (non-volatile content 25% by mass).

(Manufacture Example 20)
<Synthesis of aromatic polyimide (1)>
p-Phenylenediamine (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, pyromellitic anhydride (5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic imide precursor (1). (The non-volatile content of the varnish was 25% by mass)

(Production Example 21)
<Synthesis of aromatic polyimide (2)>
p-Phenylenediamine (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, 3,3',4,4'-diphenylethertetracarboxylic dianhydride (5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic imide precursor (2). (The non-volatile content of the varnish was 25% by mass)

(Production Example 22)
<Synthesis of aromatic polyimide (3)>
4,4'-Diaminodiphenyl ether (4.75 mol) was placed in a flask that had been dried at 60°C for 1 hour, and dissolved in ultra-dehydrated N-methyl-2-pyrrolidone (NMP). Then, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride (5 mol) that had been dried at 180°C for 5 hours was gradually added to the solution while stirring. The solution was then stirred for 24 hours at uncontrolled room temperature of 20 to 30°C, yielding a solution of aromatic imide precursor (3). (The non-volatile content of the varnish was 25% by mass)

<Method of preparing evaluation samples>
On a silicon wafer, first, titanium (Ti) was formed to a thickness of 50 nm, then copper (Cu) was formed to a thickness of 250 nm by sputtering, and then copper was grown to a thickness of 20 μm by electrolytic copper plating to prepare a substrate. Then, the photosensitive resin composition varnishes of the formulations of Examples 1 to 16 and Comparative Examples 1 to 6 shown in Tables 1 to 3 were applied to the above substrate by a spin coater, and the solvent was removed by pre-baking. Next, 500 mJ/cm ² UV light was irradiated. After cutting into the size required for evaluating the physical properties with a cutter, the evaluation samples of Examples 1 to 16 were cured for 2 hours in an N ₂ oven at 200 ° C., and the evaluation samples of Comparative Examples 1 to 6 were cured for 2 hours at 250 ° C. The conditions during film formation were adjusted so that the thickness was 10 μm after full curing. Finally, the resin sample was obtained by immersing in an aqueous solution of ammonium peroxodisulfate with a concentration of 50% by mass, etching the copper part, and washing with water.

<Evaluation of Evaluation Samples>
<Measurement of chloride ion concentration>
The chloride ion concentration was measured by using an extract from the cured product of the photosensitive resin composition and analyzing it under conditions of 30° C., 1.0 ml/min, and an injection amount of 25 μl using an apparatus (manufactured by Dionex Corporation) named "instrument name: ICS-2000,""detector: electrical conductivity detector," and "column: AS20 (diameter 4 mm×200 mm)."

<Measurement of breaking elongation>
In the preparation of the above evaluation sample, the film was formed in the same manner up to the point where the solvent was removed by pre-baking. Next, when exposing, the film was exposed through a mask having a length of 30 mm and a width of 5 mm. The obtained sample was developed and cured, and similarly to the above, it was immersed in an aqueous solution of ammonium peroxodisulfate having a concentration of 50% by mass, and the copper part was etched and washed with water to obtain a resin sample. The obtained sample was measured for breaking elongation when measured at a feed rate (tensile rate) of 5 mm/min using a small tabletop tester (manufactured by Shimadzu Corporation, product name: EZ-S).

<Measurement of dielectric properties (dielectric constant and dielectric tangent)>
The dielectric properties (dielectric constant Dk and dielectric loss tangent Df) were measured by the SPDR method using evaluation samples cut to a predetermined size. An SPDR dielectric resonator manufactured by Agilent Technologies was used for the SPDR, a vector network analyzer E8364B manufactured by Agilent Technologies was used for the measurement, and the measurement program was CPMA-V2. The conditions were a frequency of 10 GHz and a measurement temperature of 25°C.

<Measurement of 5% weight loss temperature and moisture absorption rate>
The prepared sample was left for 200 hours in a thermo-hygrostat (manufactured by Espec Corporation, product name: EHS-221MD) set at a relative humidity of 85% and 130 ° C. Then, after lowering the temperature in the thermo-hygrostat to 50 ° C., the sample was taken out, and a part of the resin was measured using a differential thermal thermogravimetric simultaneous measurement device (manufactured by Hitachi High-Tech Science Corporation, product name: TG / DTA6300) under conditions of a heating rate of 10 ° C. / min, a nitrogen flow of 400 mL / min, and a temperature range of 25 ° C. to 150 ° C. On the other hand, a similarly prepared sample was dried at 130 ° C. for 2 hours and TG-DTA was measured in the same manner. The difference in the weight loss rate at 150 ° C. was calculated as the moisture absorption rate.
The 5% weight loss temperature was measured using the same thermogravimetric and differential thermal analyzer (manufactured by Hitachi High-Tech Science Corporation, product name: TG/DTA6300) as above, under conditions of a heating rate of 10°C/min, nitrogen flow of 400 mL/min, and a temperature range of 25°C to 500°C, to determine the temperature at which the weight decreased by 5%.

<Evaluation of Pattern Formability>
The varnish prepared on a silicon wafer was applied by a spin coater, and the solvent was removed by pre-baking. Next, exposure was performed through a negative mask with a line/space of 10 μm/10 μm. The obtained sample was developed, and the pattern formability was evaluated by assigning A to samples without appearance defects such as film peeling or swelling/falling of the pattern, and B to samples with appearance defects.
The above measurement and evaluation results are shown in Tables 1 to 3.

In the case of using the aromatic polyimide resins of Comparative Examples 1 to 6, when used in combination with a (meth)acryloyl compound, the pattern formability is deteriorated. The breaking elongation is low at 25 to 50%, the water absorption is high at 2%, and further, the dielectric constant and dielectric tangent values are high, resulting in poor dielectric properties.
In contrast, the photosensitive resin compositions using the resin containing the aromatic polyesterimide structure of general formula (1) of the present invention shown in Examples 1 to 16 have excellent pattern formability, a high breaking elongation of 60 to 140%, a low water absorption of 0.2 to 0.6%, and low values of the dielectric constant and dielectric tangent, resulting in excellent dielectric properties.
When a resin containing an aromatic polyesterimide structure of the general formula (1) is used in combination with a photopolymerization initiator and a thermal radical polymerization initiator, and if necessary, a (meth)acryloyl compound (Examples 1 to 8), a photosensitive resin composition having low dielectric properties that maintains low dielectric properties and has photolithographic properties and insulating reliability can be obtained. The cured product exhibits good low dielectric properties and insulating properties and can be suitably used for an interlayer insulating film, a cover coat layer, or a surface protective film.

REFERENCE SIGNS LIST 1 Semiconductor substrate 2 Protective film 3 First conductor layer 4 Interlayer insulating film 5 Photosensitive resin layer 6A, 6B, 6C Window 7 Second conductor layer 8 Surface protective film

Claims (16)

A resin composition used for forming an insulating layer, the resin composition comprising a resin having an aromatic polyesterimide structure represented by the following general formula (1), a photopolymerization initiator, and a thermal radical polymerization initiator, and when the resin having the aromatic polyesterimide structure represented by the general formula (1) does not comprise a group represented by the following general formula (2), the resin composition further comprises a (meth)acryloyl compound.

(In general formula (1), m is an integer of 1 to 100; Ar is a benzene ring, a naphthalene ring, a pyridine ring which may have a substituent, or a divalent group connecting these with -O-, -S-, -(CO)-, -O-(CO)- or -(CO)-O-; R is a divalent group having an aromatic skeleton having 2 to 30 carbon atoms and 4 to 100 hydrogen atoms; -COOR ₁ and -COOR ₂ are each in the ortho position relative to the adjacent -CONH-; and R ₁ , R ₂ and R' are each independently a hydrogen atom or a group represented by general formula (2), or a hydrocarbon group having 1 to 4 carbon atoms.)

(In general formula (2), R ₃ to R ₅ each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and n represents an integer of 1 to 10.) A resin composition used to form an insulating layer, the resin composition being a photosensitive resin composition having low dielectric properties, comprising a resin having an aromatic polyesterimide structure represented by the following general formula (1), a photopolymerization initiator, and a thermal radical polymerization initiator:

(In general formula (1), m is an integer of 1 to 100; Ar is a divalent group having an aromatic skeleton; R is a divalent group having an aromatic skeleton having 2 to 30 carbon atoms and 4 to 100 hydrogen atoms; -COOR ₁ and -COOR ₂ are each located at the ortho position relative to the adjacent -CONH-; R ₁ , R ₂ and R' are each independently a hydrogen atom or a group represented by general formula (2) or a hydrocarbon group having 1 to 4 carbon atoms; and at least one of R ₁ , R ₂ and R' is a group represented by formula (2) .)

(In general formula (2), R ₃ to R ₅ each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and n represents an integer of 1 to 10.) The photosensitive resin composition having low dielectric properties according to claim 1 or 2 , further comprising a coupling agent. The photosensitive resin composition having low dielectric properties according to any one of claims 1 to 3 , further comprising a (meth)acryloyl compound. 5. The photosensitive resin composition having low dielectric properties according to claim 1 , wherein a chloride ion concentration in a cured product of the photosensitive resin composition having low dielectric properties according to claim 1 is 5 ppm or less. The photosensitive resin composition having low dielectric properties according to any one of claims 1 to 5 , wherein the breaking elongation of a cured product of the photosensitive resin composition having low dielectric properties according to any one of claims 1 to 4 is 10 to 200%. The photosensitive resin composition having low dielectric properties according to any one of claims 1 to 6 , wherein a cured product of the photosensitive resin composition having low dielectric properties according to any one of claims 1 to 4 has a dielectric constant of 3.2 or less at 10 GHz. The photosensitive resin composition having low dielectric properties according to any one of claims 1 to 7 , wherein a dielectric loss tangent at 10 GHz of a cured product of the photosensitive resin composition having low dielectric properties according to any one of claims 1 to 4 is 0.0100 or less. The photosensitive resin composition having low dielectric properties according to any one of claims 1 to 8 , wherein the 5% weight loss temperature of a cured product of the photosensitive resin composition having low dielectric properties according to any one of claims 1 to 4 is 300°C or higher. The photosensitive resin composition having low dielectric properties according to any one of claims 1 to 4 , wherein a cured product of the photosensitive resin composition having low dielectric properties according to any one of claims 1 to 4 has a moisture absorption rate of 1 mass% or less after being placed in an environment of 130°C and a relative humidity of 85% for 200 hours. A process for forming a photosensitive resin film by applying the photosensitive resin composition having low dielectric properties according to any one of claims 1 to 10 onto a substrate and drying the composition;
a step of exposing the photosensitive resin film to a pattern to obtain a resin film;
developing the resin film after the patterned exposure with an organic solvent to obtain a patterned resin film;
and heat-treating the patterned resin film. The method for producing a patterned cured product according to claim 11 , wherein the heat treatment temperature is 200° C. or lower . A cured product obtained by curing the photosensitive resin composition having low dielectric properties according to any one of claims 1 to 10 . The cured product according to claim 13 , which is a patterned cured product. The cured product according to claim 13 or 14 , which is used as an interlayer insulating film, a cover coat layer, or a surface protective film. An electronic component comprising the interlayer insulating film, cover coat layer or surface protective film according to claim 15 .