JP7797902B2 - Method for producing polynorbornene - Google Patents

Description

The present invention relates to a method for producing polynorbornene, a polynorbornene-containing solution, a polynorbornene powder, a photosensitive resin composition, and a semiconductor device.

Norbornene-based resins have traditionally been characterized by their excellent electrical and optical properties, low moisture absorption, and other characteristics, and have been used in a variety of molded products.

Patent Document 1 discloses a norbornene-based polymer or a polymer composition containing a norbornene-based polymer. Specifically, it describes an example of homopolymerization of 1-[4-(5-2-norbornyl)butyl]-3,4-dimethyl-pyrrole-2,5-dione (NBBuDMMI) in toluene (paragraphs 0173 and 0176).

Patent Document 2 discloses a block copolymer of a specific structure. Specifically, it describes an example of homopolymerization of NBBuDMMI in trifluorotoluene in the presence of a specific palladium catalyst, in which synthesis is carried out using 1 mole of the specific palladium catalyst per 100 moles of NBBuDMMI (paragraphs 0251 and 0253).

Furthermore, polyimide resins have high mechanical strength, heat resistance, insulating properties, and solvent resistance, and are therefore widely used as protective materials in liquid crystal display elements and semiconductors, insulating materials, and thin films for electronic materials such as color filters.
Patent Document 3 discloses a photosensitive composition containing a polyimide having a specific maleimide group at the end.

Special Publication No. 2013-541191 Special table 2017-525808 publication International Publication No. 2020/181021

However, in the conventional production method described in Patent Document 1, the weight-average molecular weight of the obtained polymer was high, leaving room for improvement in compatibility with other materials. Furthermore, the reaction was carried out in toluene, which posed a problem of residual toluene remaining in the obtained polymer.

In the conventional production method described in Patent Document 2, although the weight-average molecular weight of the obtained polymer is small, the conversion rate is low despite the reaction time being long (20 hours), and there is room for improvement in the polymer yield. Furthermore, the reaction is carried out in trifluorotoluene, which causes a problem that trifluorotoluene remains in the obtained polymer.

The present inventors have found that the above-mentioned problems can be solved by polymerizing a norbornene-based compound in a predetermined solvent other than toluene and trifluorotoluene in the presence of a palladium catalyst and a chain transfer agent, and have completed the present invention.
That is, the present invention can be shown as follows.

According to the present invention,
The method includes a step of polymerizing a norbornene-based compound in a solvent in the presence of a palladium catalyst and a chain transfer agent to obtain polynorbornene,
The solvent does not contain toluene and trifluorotoluene or contains toluene and trifluorotoluene at levels below the detection limit in GC/MS measurement,
The method for producing polynorbornene is provided, wherein the difference between the Hansen solubility parameter a of the polynorbornene and the Hansen solubility parameter b of the solvent is 8 or less.

According to the present invention,
A polynorbornene-containing solution is provided, which contains a polynorbornene containing a structural unit represented by the following general formula (1a), and which does not contain toluene and trifluorotoluene or contains toluene and trifluorotoluene at levels below the detection limit in GC/MS measurement.
(In general formula (1a), ^R1 and ^R2 each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; ^Q1 represents a single bond or a divalent organic group; ^G1 , ^G2 , and ^G3 each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms; and m is 0, 1, or 2.)

According to the present invention,
There is provided a polynorbornene powder containing a structural unit represented by the general formula (1a), which is free of toluene and trifluorotoluene or contains toluene and trifluorotoluene at levels below the detection limit in GC/MS measurement.

According to the present invention,
A photosensitive resin composition is provided, which contains the polynorbornene powder and a polyimide.

According to the present invention,
A cured film is provided which is made of a cured product of the photosensitive resin composition.

According to the present invention,
There is also provided a semiconductor device comprising a resin film containing a cured product of the photosensitive resin composition.

According to the present invention, polynorbornene having a small weight-average molecular weight and excellent compatibility with other materials can be obtained, and a method for producing polynorbornene with a high yield can be provided. Furthermore, according to the present invention, polynorbornene can be provided that does not contain toluene or trifluorotoluene or that contains toluene or trifluorotoluene at or below the detection limit in GC/MS measurement. Furthermore, according to the present invention, since polynorbornene has excellent compatibility with other materials, a photosensitive resin composition containing polynorbornene and polyimide can be provided.

1 is a schematic cross-sectional view of a semiconductor device according to an embodiment of the present invention;

Embodiments of the present invention will be described below with reference to the drawings. Note that in all drawings, similar components will be given similar reference numerals, and descriptions will be omitted where appropriate. For example, "1 to 10" represents "1 or more" to "10 or less" unless otherwise specified.

The method for producing polynorbornene according to the present embodiment includes a step of polymerizing a norbornene-based compound in a solvent in the presence of a palladium catalyst and a chain transfer agent.
In this embodiment, for example, a norbornene-based compound, a palladium catalyst, and a chain transfer agent are dissolved in a solvent, and then the solution is heated for a predetermined period of time, thereby carrying out solution polymerization.
At this time, the heating temperature can be, for example, 30°C to 120°C, preferably 40°C to 100°C, and more preferably 50°C to 80°C.

The heating time can be, for example, 0.5 to 10 hours. It is more preferable to carry out solution polymerization after removing moisture from the reaction system by aerating with nitrogen.

(Norbornene-based compounds)
As the norbornene-based compound of this embodiment, any known norbornene-based compound can be used as long as the effects of the present invention are achieved, but it is preferable to use a compound represented by the following general formula (1).

In general formula (1), ^R1 and ^R2 each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and at least one of them is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably both are alkyl groups having 1 to 3 carbon atoms. From the viewpoint of the effects of the present invention, the alkyl group having 1 to 3 carbon atoms is preferably an alkyl group having 1 or 2 carbon atoms, and more preferably an alkyl group having 1 carbon atom.

^Q1 represents a single bond or a divalent organic group.
The divalent organic group can be any known organic group as long as it achieves the effects of the present invention, and examples thereof include an alkylene group having 1 to 8 carbon atoms or a (poly)alkylene glycol chain. The alkylene group having 1 to 8 carbon atoms is preferably an alkylene group having 2 to 6 carbon atoms.

Examples of alkylene groups having 1 to 8 carbon atoms include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, and octylene groups.

The alkylene oxide that constitutes the (poly)alkylene glycol chain is not particularly limited, but is preferably an alkylene oxide having 1 to 18 carbon atoms, and more preferably an alkylene oxide having 2 to 8 carbon atoms, such as ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, 1-butene oxide, 2-butene oxide, trimethylethylene oxide, tetramethylene oxide, tetramethylethylene oxide, butadiene monoxide, and octylene oxide.

G ¹ , G ² and G ³ each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms.

Examples of hydrocarbon groups having 1 to 30 carbon atoms include alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, and cycloalkyl groups.

Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, and decyl groups.
Alkenyl groups include, for example, allyl, pentenyl, and vinyl groups, and alkynyl groups include ethynyl groups.
Alkylidene groups include, for example, methylidene and ethylidene groups.

Examples of aryl groups include phenyl, naphthyl, and anthracenyl groups. Examples of aralkyl groups include benzyl and phenethyl groups.

Examples of the alkaryl group include tolyl and xylyl groups, and examples of the cycloalkyl group include adamantyl, cyclopentyl, cyclohexyl, and cyclooctyl groups.
The hydrocarbon group having 1 to 30 carbon atoms may contain at least one atom selected from O, N, S, P and Si in its structure.

In this embodiment, the hydrocarbon group having 1 to 30 carbon atoms is preferably a hydrocarbon group having 1 to 15 carbon atoms, and more preferably a hydrocarbon group having 1 to 10 carbon atoms. Furthermore, the hydrocarbon group having 1 to 30 carbon atoms is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and even more preferably an alkyl group having 1 to 10 carbon atoms.

Substituents on the substituted hydrocarbon group having 1 to 30 carbon atoms include hydroxyl groups, amino groups, cyano groups, ester groups, ether groups, amide groups, and sulfonamide groups, and the group may be substituted with at least one type of group.

In this embodiment, it is preferred that one of G ¹ , G ² and G ³ is a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, and the rest are hydrogen atoms, and it is more preferred that all are hydrogen atoms.
m is 0, 1 or 2, preferably 0 or 1, and more preferably 0.

The polynorbornene of this embodiment has structural units derived from the compound of general formula (1), and therefore has an excellent low dielectric loss tangent. Furthermore, the polynorbornene has a specific maleimide group in its side chain, which allows for photodimerization without causing a radical reaction. This allows for photopolymerization of polynorbornene units, resulting in excellent mechanical strength.

(solvent)
The solvent used in the polymerization reaction of this embodiment does not contain toluene or trifluorotoluene. Furthermore, in this embodiment, a solvent is used in which the difference between the Hansen solubility parameter a of the resulting polynorbornene and the Hansen solubility parameter b of the solvent (Hansen distance Ra) is 8 or less, preferably 7 or less, and more preferably 6 or less.

In this embodiment, the Hansen solubility parameter a of polynorbornene is measured by the following method.
[method]
To a 5 ml glass container, 0.05 g of polynorbornene is added with 1 ml of any solvent selected from the evaluation solvents listed below, and the mixture is stirred for 1 hour using a mix rotor. The dispersibility is then visually evaluated using the following three-point scale. All evaluation solvents and the evaluation results for dispersibility in each solvent are input into the Sphere program of the computer software HSPiP (version 5.2.02), and the Hansen solubility parameter is calculated.
(Solvent for evaluation)
Hexane, cyclohexane, toluene, benzyl benzoate, propylene carbonate, 1-hexene, methyl ethyl ketone, acetone, acetonitrile, ethyl acetate, propylene glycol monomethyl ether acetate, cyclohexanol, isopropyl alcohol, methanol (Evaluation)
1: Completely dissolved.
2: Partially dissolved.
6: Does not dissolve.

By using a solvent whose Hansen distance with polynorbornene is within a specified range, the synthesis reaction proceeds smoothly due to excellent solubility of polynorbornene, even without the use of toluene or trifluorotoluene, and the conversion rate is excellent, resulting in an improved yield. Furthermore, since polynorbornene powder is obtained, handling is also easy.

The Hansen solubility parameter is an index of solubility that indicates how much a substance dissolves in another substance. The Hansen solubility parameter can be expressed as a three-dimensional vector, specifically, by a dispersion term (δ _D ), a polarization term (δ _P ), and a hydrogen bonding term (δ _H ).

In this embodiment, the Hansen distance Ra is the distance between the polynorbornene (A) and the solvent (B) in a three-dimensional space having the dispersion term (δ _D ), the polarization term (δ _P ), and the hydrogen bond term (δ _H ) as coordinates, and specifically, can be calculated by the following formula.
Formula: Ra = [4(δ _DA - δ _DB ) ² + (δ _PA - δ _PB ) ² + (δ _HA - _{δ HB} ) ² ] ^1/2

The smaller the value of the Hansen distance Ra, the better the compatibility between the polynorbornene (A) and the solvent (B), and it is preferable that the Hansen distance Ra is within the above range.

The solvent may be one type of solvent or a mixed solvent of two or more types of solvents.
The solvent is not particularly limited as long as it satisfies the above range of the Hansen distance Ra, but from the viewpoint of the effects of the present invention, it is preferable that the solvent contains at least one selected from ether-based solvents and hydrocarbon-based solvents that do not contain an aromatic ring.

As the ether solvent, any known solvent can be used as long as the effects of the present invention are achieved, and it is preferable that the ether solvent contains at least one selected from, for example, cyclopentyl methyl ether and methyl tetrahydropyran.
By including these solvents, powdery polynorbornene can be suitably obtained in the reprecipitation step described below.

The hydrocarbon solvent not containing an aromatic ring can be any known solvent as long as it achieves the effects of the present invention. For example, it is preferable that the solvent contains at least one selected from cyclohexane and methylcyclohexane.

More preferably, the solvent is a mixed solvent of ethyl acetate and at least one selected from cyclopentyl methyl ether, methyltetrahydropyran, cyclohexane, and methylcyclohexane.

When the solvent is a mixed solvent of two or more types, it is preferable that the difference (Hansen distance Ra) between the Hansen solubility parameter a of the polynorbornene and the Hansen solubility parameter c of the mixed solvent of two or more types be within the above range.

(Palladium catalyst)
The palladium catalyst is not particularly selected as long as it allows addition polymerization to proceed, but for example, a palladium complex may be coordinated with a phosphine or diimine ligand to form a counter anion, etc. One or more of these may be used.

Examples of the palladium complex include allylpalladium complexes such as (acetato-κ0)(acetonitrile)bis[tris(1-methylethyl)phosphine]palladium(I) tetrakis(2,3,4,5,6-pentafluorophenyl)borate and π-allylpalladium chloride dimer;
Palladium organic carboxylates such as palladium acetate, propionate, maleate, and naphthoate;
complexes of palladium with organic carboxylic acids, such as a triphenylphosphine complex of palladium acetate, a tri(m-tolyl)phosphine complex of palladium acetate, and a tricyclohexylphosphine complex of palladium acetate;
palladium dibutyl phosphite, palladium p-toluenesulfonate and other organic sulfonates of palladium;
β-diketone compounds of palladium such as bis(acetylacetonato)palladium, bis(hexafluoroacetylacetonato)palladium, bis(ethylacetoacetate)palladium, and bis(phenylacetoacetate)palladium;
Examples thereof include dichlorobis(triphenylphosphine)palladium, bis[tri(m-tolylphosphine)]palladium, dibromobis[tri(m-tolylphosphine)]palladium, and halide complexes of palladium such as acetonyltriphenylphosphonium complex.

Examples of the phosphine ligand include triphenylphosphine, dicyclohexylphenylphosphine, cyclohexyldiphenylphosphine, and tricyclohexylphosphine.

Examples of the counter anion include triphenylcarbenium tetrakis(pentafluorophenyl)borate, triphenylcarbenium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, triphenylcarbenium tetrakis(2,4,6-trifluorophenyl)borate, triphenylcarbenium tetraphenylborate, tributylammonium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N-diphenylanilinium tetrakis(pentafluorophenyl)borate, and lithium tetrakis(pentafluorophenyl)borate.

The amount of palladium catalyst can be from 1/20,000 mol to 1/500 mol, preferably from 1/10,000 mol to 1/1,000 mol, and more preferably from 1/5,000 mol to 1/2,000 mol, per mole of the norbornene compound. This can further improve the yield of polynorbornene.

In this embodiment, the use of a norbornene compound and a specified solvent reduces the amount of palladium catalyst used in the reaction, and the amount of residual palladium contained in the resulting polynorbornene can be reduced, resulting in polynorbornene with excellent dielectric properties such as dielectric dissipation factor.

(Chain transfer agent)
In this embodiment, the chain transfer agent can be a known chain transfer agent as long as the effects of the present invention are achieved. However, it is preferable that the chain transfer agent contains at least one selected from a compound represented by the following general formula (a), formic acid, and oxalic acid:
By using a chain transfer agent, the amount of palladium catalyst can be reduced, and furthermore, polynorbornene having a small weight average molecular weight can be obtained.

In general formula (a), R ¹ , R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms.
Examples of the compound represented by the general formula (a) include trimethylsilane, triethylsilane, and tributylsilane.

The chain transfer agent can be used in an amount of preferably 5 to 50 parts by weight, more preferably 10 to 40 parts by weight, per 100 parts by weight of the norbornene-based compound.

(Other ingredients)
In addition, during the reaction, a molecular weight modifier, a promoter, etc. may be added as necessary.

The co-catalyst preferably contains an ion complex containing a weakly coordinating anion salt. In other words, when synthesizing the addition-type norbornene-based resin, it is preferable to add a co-catalyst in addition to the catalyst. This can further increase the polymerization rate of the addition-type norbornene-based monomer.

The co-catalyst is not particularly limited, but examples include alkylaluminum, Lewis acids, and ionic complexes containing weakly coordinating anion (WCA) salts, and among these, ionic complexes containing weakly coordinating anion (WCA) salts are preferred.

Furthermore, the promoter is more preferably one represented by the following formula (i):
[C] _e [WCA] _d formula (i)
(In the above formula, C represents a proton (H ⁺ ), an organic radical-containing cation, or an alkali metal, alkaline earth metal, or transition metal cation; WCA is as defined above; and e and d are numbers determined to balance the electronic charge on the overall salt complex of the cation complex (C) and the weakly coordinating anion salt (WCA), respectively.)

Examples of ionic complexes containing the weakly coordinating anion (WCA) salt include, but are not limited to, lithium(diethyl ether) _2.5 tetrakis(pentafluorophenyl)borate, dimethylanilinium tetrakis(pentafluorophenyl)borate, dimethylanilinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, H( _OEt2 ) _x tetrakis(pentafluorophenyl)borate, tetrakis[(4-methyl)-α,α-bis(trifluoromethyl)benzenemethanolato-κO]aluminate, sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, trialkyl and triarylphosphonium tetrakis(pentafluorophenyl)borate, and trityl tetrakis(pentafluorophenyl)borate.

The co-catalyst can be used in an amount of 1/20,000 mol to 1/500 mol, preferably 1/10,000 mol to 1/1,000 mol, and more preferably 1/5,000 mol to 1/2,000 mol per 1 mol of the norbornene compound. This can further improve the yield of polynorbornene.

[Reprecipitation process, etc.]

The above steps allow for the production of a reaction solution containing the polynorbornene of this embodiment, which can be further diluted with an organic solvent or the like as needed and used as a polymer solution. The organic solvent used can be one of those exemplified in the reaction step, and may be the same organic solvent as in the reaction step or a different organic solvent.

Alternatively, this polymer solution can be poured into a poor solvent to reprecipitate polynorbornene, remove unreacted monomers, and then dry and solidify to obtain polynorbornene powder. Examples of poor solvents include alcohols such as hexane, methanol, and isopropyl alcohol, as well as water, and these can also be used in combination.

The obtained polynorbornene powder can be dissolved again in an organic solvent and used as a purified product (polynorbornene-containing solution). In particular, in applications where impurities or foreign matter are a problem, it is preferable to dissolve it again in an organic solvent.
The polynorbornene concentration in the polynorbornene-containing solution (100% by weight) is not particularly limited, but is about 30 to 70% by weight.

The amount of poor solvent used is 15 to 150 times the weight of the polynorbornene-containing solution (100% by weight). The amount of poor solvent used varies depending on the type of solvent used in polymerization, and powdery polynorbornene can be obtained by using 50 to 150 times the amount of poor solvent when a hydrocarbon solvent is used, or 15 to 50 times the amount when an ether solvent is used.

The method for producing polynorbornene according to the present embodiment does not use toluene or trifluorotoluene as a solvent, and therefore the polynorbornene powder and the polynorbornene-containing solution do not contain these solvents.
Even when toluene or trifluorotoluene is used in the synthesis of norbornene as a raw material, these solvents are not used in the production method of polynorbornene, so the reaction solvent does not contain toluene and trifluorotoluene or is below the detection limit in GC/MS measurement, and further, since the polynorbornene undergoes a purification process (reprecipitation process, etc.), the polynorbornene powder and polynorbornene-containing solution do not contain toluene and trifluorotoluene or is below the detection limit in GC/MS measurement. In particular, the polynorbornene-containing solution can be prepared by dissolving the polymer powder obtained through the reprecipitation process in a solvent, so that a polynorbornene-containing solution free of toluene and trifluorotoluene can be obtained.
In this embodiment, toluene and trifluorotoluene being below the detection limit means that the amounts are below the detection limit when the purified polynorbornene is measured by gas chromatography mass spectrometry (GC/MS).

The polynorbornene of this embodiment contains a structural unit represented by the following general formula (1a):

In formula (1a), R ¹ , R ² , Q ¹ , G ¹ , G ² , G ³ and m have the same meanings as in formula (1).

According to the production method of this embodiment, polynorbornene with a low weight-average molecular weight can be obtained, and the weight-average molecular weight can be preferably 15,000 or less, more preferably 12,000 or less, and even more preferably 10,000 or less. The lower limit of the weight-average molecular weight is not particularly limited, but can be preferably 2,000 or more, more preferably 3,000 or more, and even more preferably 5,000 or more.
When the weight average molecular weight is within the above range, the polynorbornene has excellent compatibility with other materials, for example, with polyimide, and therefore a photosensitive resin composition can be suitably obtained.

The dispersity (Mw/Mn) of polynorbornene is, for example, 1.0 or more and 8.0 or less, preferably 1.2 or more and 5.0 or less, and more preferably 1.5 or more and 3.0 or less. By keeping the dispersity within the above range, polynorbornene has even better compatibility with other materials.

In this embodiment, the weight-average molecular weight of polynorbornene can be measured by obtaining a molecular weight distribution curve using gel permeation chromatography (GPC). The weight-average molecular weight (Mw), number-average molecular weight (Mn), and polydispersity index (PDI: Mw/Mn) of polynorbornene are calculated using polystyrene-equivalent values obtained from a calibration curve of standard polystyrene (PS) obtained by GPC measurement.
The measurement conditions for GPC are, for example, as follows.
Gel permeation chromatography device HLC-8320GPC manufactured by Tosoh Corporation
Column: TSK-GEL GMH, G2000H, Super HM-M manufactured by Tosoh Corporation
Detector: RI detector for liquid chromatography Measurement temperature: 40°C
Solvent: THF
Sample concentration: 5.0 mg/milliliter

The manufacturing method of this embodiment uses a small amount of palladium catalyst in the reaction, which reduces the amount of residual palladium contained in the resulting polynorbornene powder, resulting in excellent dielectric properties such as dielectric dissipation factor.

<Photosensitive resin composition>
The photosensitive resin composition of the present embodiment contains the above-described polynorbornene powder and polyimide.

[Polyimide]
In the polyimide of this embodiment, at least one of both ends is preferably a group t represented by the following general formula (t), and more preferably both ends are the group t.

In general formula (t), ^R5 and ^R6 each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and from the viewpoint of the effects of the present invention, an alkyl group having 1 or 2 carbon atoms is preferred, and an alkyl group having 1 carbon atom is more preferred. * represents a bond.

^Q2 represents a divalent organic group.
As the divalent organic group, any known organic group can be used as long as the effects of the present invention are achieved. For example, a divalent organic group represented by the following general formula (t-1) is preferred.

In general formula (t-1), R ¹ to R ⁴ each independently represent an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, R ¹ and R ² are different groups, and R ³ and R ⁴ are different groups.
From the viewpoint of the effects of the present invention, R ¹ to R ⁴ are preferably alkyl groups having 1 to 3 carbon atoms.

X ¹ represents a single bond, —SO ₂ —, —C(═O)—, a linear or branched alkylene group having 1 to 5 carbon atoms, or a linear or branched fluoroalkylene group having 1 to 5 carbon atoms, and multiple X ^1s may be the same or different.

From the viewpoint of the effects of the present invention, ^X1 is preferably a single bond, a linear or branched alkylene group having 1 to 5 carbon atoms, or a linear or branched fluoroalkylene group having 1 to 5 carbon atoms, and more preferably a linear or branched alkylene group having 1 to 5 carbon atoms, or a linear or branched fluoroalkylene group having 1 to 5 carbon atoms.
* indicates a bond.

The polyimide of this embodiment has excellent mechanical strength because it contains a polyimide having a group t represented by general formula (t) at at least one end. Furthermore, the polyimide can be photodimerized without causing a radical reaction, which results in even greater mechanical strength.
The polyimide may also include a polyimide having a group u represented by the following general formula (u) at its terminal.

In formula (u), X ¹ and R ¹ to R ⁴ have the same meanings as in formula (t-1).

When the polyimide contains a polyimide having the group u, the ratio of the number of moles of group t to the total number of moles of group t and group u (t/t+u) can be 0.5 or greater, preferably 0.55 or greater, and more preferably 0.6 or greater. Within this range, the amount of polyimide components eluted during development can be reduced.

The polyimide of this embodiment preferably contains a structural unit (a1) represented by the following general formula (a1) and a structural unit (a2) represented by the following general formula (a2):

In formula (a1), Y represents a divalent organic group.
As the divalent organic group, any known organic group can be used as long as the effects of the present invention are achieved. However, from the viewpoint of the effects of the present invention, a divalent organic group selected from the following general formula (a1-1), the following general formula (a1-2), and the following general formula (a1-3) is preferred.

In general formula (a1-1), R ⁷ and R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and multiple R ^7s and multiple R ^8s may be the same or different.
From the viewpoint of the effects of the present invention, R ⁷ and R ⁸ are preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom.
R ⁹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and multiple R ^9s may be the same or different.
From the viewpoint of the effects of the present invention, R ⁹ is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom.
* indicates a bond.

In general formula (a1-2), R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and multiple R ^10s and multiple R ^11s may be the same or different.

From the viewpoint of the effects of the present invention, R ¹⁰ and R ¹¹ are preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably at least one of R ¹⁰ and at least one of R ¹¹ are an alkyl group having 1 to 3 carbon atoms, even more preferably three R ¹⁰ are alkyl groups having 1 to 3 carbon atoms and one R ¹⁰ is a hydrogen atom, and three R ¹¹ are alkyl groups having 1 to 3 carbon atoms and one R ¹¹ is a hydrogen atom, and particularly preferably three R ¹⁰ are methyl groups and one R ¹⁰ is a hydrogen atom, and three R ¹¹ are methyl groups and one R ¹¹ is a hydrogen atom.
* indicates a bond.

In general formula (a1-3), Z represents an alkylene group having 1 to 5 carbon atoms or a divalent aromatic group.
* indicates a bond.

In formula (a2), R ¹ to R ⁴ and X ¹ have the same meanings as in formula (t-1).

By including a structural unit represented by general formula (a2) in the polyimide of this embodiment, the effect on the electrons in the imide ring is suppressed, thereby suppressing hydrolysis of the polyimide, resulting in excellent mechanical strength such as elongation, as well as excellent solubility in organic solvents. In other words, the polyimide of this embodiment and the photosensitive resin composition containing the polyimide have an excellent balance of these properties.

The polyimide may further contain a structural unit (a3) represented by the following general formula (a3):

In general formula (a3), ^R5 and ^R6 each independently represent a hydrogen atom, a haloalkyl group having 1 to 4 carbon atoms, or a hydroxyl group, and are preferably a hydrogen atom or a haloalkyl group having 1 to 4 carbon atoms. Multiple ^R5s may be the same or different, and multiple ^R6s may be the same or different.

X represents a single bond, an alkylene group having 1 to 4 carbon atoms, or a haloalkylene group having 1 to 4 carbon atoms, and is preferably a single bond or a haloalkylene group having 1 to 4 carbon atoms.
m and n each independently represent 0 or 1;

In the general formula (t), the divalent organic group of ^Q2 may be the structural unit (a3) represented by the general formula (a3). Specifically, a divalent organic group represented by the following general formula (t-2) can be mentioned.

In formula (t-2), R ⁵ , R ⁶ , X, m, and n have the same meanings as in formula (a3).
* indicates a bond.

Specifically, the polyimide of this embodiment can include structural unit 1 represented by the following general formula (1):

In formula (1), R ¹ to R ⁴ and X ¹ have the same meanings as in formula (t-1), and Y has the same meaning as in formula (a1).

Specifically, the polyimide of this embodiment may contain, in addition to structural unit 1, structural unit 2 represented by the following general formula (2):

In formula (2), R ⁵ to R ⁶ , X, m, and n have the same meanings as in formula (a3), and Y has the same meaning as in formula (a1).

The weight-average molecular weight of the polyimide of this embodiment is 5,000 to 200,000, and preferably 10,000 to 100,000.

[Photosensitizer]
The photosensitive resin composition of the present embodiment may further contain a photosensitizer.

Examples of photosensitizers include benzophenone-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, benzil-based photopolymerization initiators, and Michler's ketone-based photopolymerization initiators. Of these, benzophenone-based photopolymerization initiators and thioxanthone-based photopolymerization initiators are preferred.

Benzophenone-based photopolymerization initiators include benzophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, 4-phenylbenzophenone, isophthalphenone, and 4-benzoyl-4'-methyl-diphenyl sulfide. These benzophenones and their derivatives can improve the curing rate by using tertiary amines as hydrogen donors.

Commercially available benzophenone-based photopolymerization initiators include, for example, SPEEDCUREMBP (4-methylbenzophenone), SPEEDCUREMBB (methyl-2-benzoylbenzoate), SPPEDCUREBMS (4-benzoyl-4'methyldiphenyl sulfide), SPPEDCUREPBZ (4-phenylbenzophenone), and SPPEDCUREEMK (4,4'-bis(diethylamino)benzophenone) (all trade names, manufactured by DKSH Japan Co., Ltd.).

Thioxanthone-based photopolymerization initiators include thioxanthone, diethylthioxanthone, isopropylthioxanthone, and chlorothioxanthone. Preferred diethylthioxanthone is 2,4-diethylthioxanthone, preferred isopropylthioxanthone is 2-isopropylthioxanthone, and preferred chlorothioxanthone is 2-chlorothioxanthone. Among these, thioxanthone-based photopolymerization initiators containing diethylthioxanthone are even more preferred.

Commercially available thioxanthone photopolymerization initiators include, for example, Speedcure DETX (2,4-diethylthioxanthone), Speedcure ITX (2-isopropylthioxanthone), Speedcure CTX (2-chlorothioxanthone), SPEEDCURE PTX (1-chloro-4-propylthioxanthone) (all trade names, manufactured by DKSH Japan Co., Ltd.), and KAYACUREDETX (2,4-diethylthioxanthone) (trade name, manufactured by Nippon Kayaku Co., Ltd.).

The amount of photosensitizer added is not particularly limited, but is preferably approximately 0.05 to 10 mass% of the total solids content of the photosensitive resin composition, more preferably approximately 0.1 to 7.5 mass%, and even more preferably approximately 0.2 to 5 mass%. Setting the amount of photosensitizer added within this range can improve the patterning ability of the photosensitive resin layer containing the photosensitive resin composition and can also improve the long-term storage stability of the photosensitive resin composition.

[Adhesion aid]
The photosensitive resin composition of the present embodiment may further contain an adhesion aid.
This can improve the adhesion between the substrate and the resin film or pattern formed from the photosensitive resin composition.

There are no particular limitations on the adhesion aid that can be used. Examples of suitable silane coupling agents include aminosilane, epoxysilane, acrylicsilane, mercaptosilane, vinylsilane, ureidosilane, acid anhydride-functional silane, and sulfidesilane. Silane coupling agents may be used alone or in combination. Among these, epoxysilanes (i.e., compounds containing both an epoxy moiety and a group that generates a silanol group upon hydrolysis in one molecule) or acid anhydride-functional silanes (i.e., compounds containing both an acid anhydride group and a group that generates a silanol group upon hydrolysis in one molecule) are preferred. The group opposite the silane of the silane coupling agent bonds with polymer A or polyimide or improves compatibility with the polymer, thereby further improving the adhesion of resin films and patterns formed from the photosensitive resin composition to the substrate.

Examples of aminosilanes 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 silanes include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidylpropyltrimethoxysilane.

Examples of the acrylic silane include γ-(methacryloxypropyl)trimethoxysilane, γ-(methacryloxypropyl)methyldimethoxysilane, and γ-(methacryloxypropyl)methyldiethoxysilane.
An example of the mercaptosilane is 3-mercaptopropyltrimethoxysilane.

Examples of vinylsilanes include vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, and vinyltrimethoxysilane.
Examples of ureidosilanes include 3-ureidopropyltriethoxysilane.
An example of an acid anhydride functional silane is 3-trimethoxysilylpropylsuccinic anhydride.

Examples of sulfide silanes include bis(3-(triethoxysilyl)propyl)disulfide and bis(3-(triethoxysilyl)propyl)tetrasulfide.
When an adhesion aid is used, only one kind may be used, or two or more kinds may be used in combination.

The content of the adhesion aid is typically 0.01 to 10 parts by mass, and preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the total solids content of the photosensitive resin composition. It is believed that by using an amount within this range, it is possible to obtain sufficient adhesion, which is the effect of the adhesion aid, while maintaining a balance with other performance properties.

(solvent)
The photosensitive resin composition according to this embodiment may contain a urea compound or an amide compound having a non-cyclic structure as a solvent. The solvent preferably contains, for example, a urea compound. This can further improve the adhesion between a cured product of the photosensitive resin composition and metals such as Al and Cu.

In this specification, a urea compound refers to a compound having a urea bond, i.e., a urea bond. An amide compound refers to a compound having an amide bond, i.e., an amide. Specific examples of amides include primary amides, secondary amides, and tertiary amides.

In addition, in this embodiment, a non-cyclic structure means that the compound structure does not include a cyclic structure such as a carbon ring, inorganic ring, or heterocyclic ring. Examples of compound structures that do not include a cyclic structure include a linear chain structure and a branched chain structure.

Preferred urea compounds and non-cyclic amide compounds have a large number of nitrogen atoms in their molecular structure. Specifically, it is preferable for the molecular structure to have two or more nitrogen atoms. This increases the number of lone electron pairs, thereby improving adhesion to metals such as Al and Cu.

Specific examples of the structure of the urea compound include a cyclic structure and an acyclic structure. Of the above specific examples, the structure of the urea compound is preferably an acyclic structure. This improves adhesion between the cured product of the photosensitive resin composition and metals such as Al and Cu. The reason for this is presumed to be as follows: urea compounds with an acyclic structure are presumed to form coordinate bonds more easily than urea compounds with a cyclic structure. This is thought to be because urea compounds with an acyclic structure have less constraints on molecular movement and a greater degree of freedom for deformation of the molecular structure than urea compounds with a cyclic structure. Therefore, when a urea compound with an acyclic structure is used, strong coordinate bonds can be formed, improving adhesion.

Specific examples of urea compounds include tetramethylurea (TMU), 1,3-dimethyl-2-imidazolidinone, N,N-dimethylacetamide, tetrabutylurea, N,N'-dimethylpropyleneurea, 1,3-dimethoxy-1,3-dimethylurea, N,N'-diisopropyl-O-methylisourea, O,N,N'-triisopropylisourea, O-tert-butyl-N,N'-diisopropylisourea, O-ethyl-N,N'-diisopropylisourea, and O-benzyl-N,N'-diisopropylisourea. Urea compounds can be used alone or in combination of two or more of the above specific examples. Of the specific examples listed above, the urea compound is preferably one or more selected from the group consisting of tetramethylurea (TMU), tetrabutylurea, 1,3-dimethoxy-1,3-dimethylurea, N,N'-diisopropyl-O-methylisourea, O,N,N'-triisopropylisourea, O-tert-butyl-N,N'-diisopropylisourea, O-ethyl-N,N'-diisopropylisourea, and O-benzyl-N,N'-diisopropylisourea, with tetramethylurea (TMU) being more preferred. This allows for the formation of strong coordinate bonds and improved adhesion.

Specific examples of the amide compound having a non-cyclic structure include 3-methoxy-N,N-dimethylpropanamide, N,N-dimethylformamide, N,N-dimethylpropionamide, N,N-diethylacetamide, 3-butoxy-N,N-dimethylpropanamide, and N,N-dibutylformamide.
The photosensitive resin composition according to this embodiment may contain, as a solvent, a solvent not having a nitrogen atom, in addition to the urea compound and the amide compound having a non-cyclic structure.

Specific examples of solvents that do not contain nitrogen atoms include ether-based solvents, acetate-based solvents, alcohol-based solvents, ketone-based solvents, lactone-based solvents, carbonate-based solvents, sulfone-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. As solvents that do not contain nitrogen atoms, one or a combination of two or more of the above specific examples can be used.

Specific examples of the ether solvent include propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, dipropylene glycol monomethyl ether, and 1,3-butylene glycol-3-monomethyl ether.

Specific examples of the acetate solvent include propylene glycol monomethyl ether acetate (PGMEA), methyl lactate, ethyl lactate, butyl lactate, and methyl-1,3-butylene glycol acetate.

Specific examples of the alcohol solvent include tetrahydrofurfuryl alcohol, benzyl alcohol, 2-ethylhexanol, butanediol, and isopropyl alcohol.
Specific examples of the ketone solvent include cyclopentanone, cyclohexanone, diacetone alcohol, and 2-heptanone.
Specific examples of the lactone solvent include γ-butyrolactone (GBL) and γ-valerolactone.
Specific examples of the carbonate solvent include ethylene carbonate and propylene carbonate.
Specific examples of the sulfone solvent include dimethyl sulfoxide (DMSO) and sulfolane.
Specific examples of the ester solvent include methyl pyruvate, ethyl pyruvate, and methyl-3-methoxypropionate.
Specific examples of the aromatic hydrocarbon solvent include mesitylene, toluene, and xylene.

Of the above solvents, PGMEA and cyclopentanone are more preferred. Using these solvents can improve the solubility of polymer A (polynorbornene) and polyimide (polyimide).

(Surfactant)
The photosensitive resin composition according to this embodiment may further contain a surfactant.

Surfactants are not limited to, but include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene aryl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether; nonionic surfactants such as polyoxyethylene dialkyl esters such as polyoxyethylene dilaurate and polyoxyethylene distearate; Eftop EF301, Eftop EF303, Eftop EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafac F171, Megafac F172, Megafac F173, Megafac F177, and Megafac F444. , Megafac F470, Megafac F471, Megafac F475, Megafac F482, Megafac F477 (manufactured by DIC Corporation), Fluorad FC-430, Fluorad FC-431, Novec FC4430, Novec FC4432 (manufactured by 3M Japan Ltd.), Surflon S-381, Surflon S-382, Surflon S-383, Surflon S-393, Surflon SC-101, Surflon SC-102, Surflon SC-103, Surflon SC-104, Surflon SC-105, Surflon SC-106, (manufactured by AGC Seimi Chemical Co., Ltd.), and other commercially available fluorine-based surfactants; organosiloxane copolymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.); (meth)acrylic acid copolymer Polyflow No. Examples include 57 and 95 (manufactured by Kyoeisha Chemical Co., Ltd.).

Among these, it is preferable to use a fluorosurfactant having a perfluoroalkyl group. As the fluorosurfactant having a perfluoroalkyl group, it is preferable to use one or more selected from the following specific examples: Megafac F171, Megafac F173, Megafac F444, Megafac F470, Megafac F471, Megafac F475, Megafac F482, Megafac F477 (manufactured by DIC Corporation), Surflon S-381, Surflon S-383, Surflon S-393 (manufactured by AGC Seimi Chemical Co., Ltd.), Novec FC4430, and Novec FC4432 (manufactured by 3M Japan Ltd.).

Also preferably used as the surfactant are silicone surfactants (such as polyether-modified dimethylsiloxanes). Specific examples of silicone surfactants include the SH series, SD series, and ST series from Dow Corning Toray Co., Ltd., the BYK series from BYK Japan, the KP series from Shin-Etsu Chemical Co., Ltd., the Disform (registered trademark) series from NOF Corporation, and the TSF series from Toshiba Silicones.

The upper limit of the surfactant content in the photosensitive resin composition is preferably 1% by mass (10,000 ppm) or less, more preferably 0.5% by mass (5,000 ppm) or less, and even more preferably 0.1% by mass (1,000 ppm) or less, based on the total amount of the photosensitive resin composition (including the solvent).

Furthermore, there is no particular lower limit for the content of the surfactant in the photosensitive resin composition, but from the viewpoint of obtaining a sufficient effect of the surfactant, the content is, for example, 0.001 mass % (10 ppm) or more of the entire photosensitive resin composition (including the solvent).
By appropriately adjusting the amount of surfactant, it is possible to improve the coatability and the uniformity of the coating film while maintaining other performance properties.

(antioxidant)
The photosensitive resin composition according to this embodiment may further contain an antioxidant. As the antioxidant, one or more selected from a phenol-based antioxidant, a phosphorus-based antioxidant, and a thioether-based antioxidant can be used. The antioxidant can suppress oxidation of the resin film formed from the photosensitive resin composition.

Phenol-based antioxidants include pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}2,4,8,10-tetraoxaspiro[5,5]undecane, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 1,6-hexanediol-bis[3-(3,5-di-t- butyl-4-hydroxyphenyl)propionate], 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5-di-t-butyl-4-hydroxyphenyl)propionate, distearyl (3,5-di-t-butyl-4-hydroxybenzyl)phosphonate, thiodiethylene ethylene glycol bis[(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(6-t-butyl-m-cresol), 2-octylthio-4,6-di(3,5-di-t-butyl-4-hydroxyphenoxy)-s-triazine, 2,2'-methylenebis(4-methyl-6-t-butyl-6-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), bis[3,3-bis(4-hydroxy-3-t-butylphenyl)butylazone] cid] glycol ester, 4,4'-butylidenebis(6-t-butyl-m-cresol), 2,2'-ethylidenebis(4,6-di-t-butylphenol), 2,2'-ethylidenebis(4-s-butyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, bis[2-t-butyl-4-methyl-6-(2-hydroxy-3-t-butyl-5-methylbenzyl)phenyl]terephthalate, 1,3,5-tris(2,6-dimethyl- 3-hydroxy-4-t-butylbenzyl)isocyanurate, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 1,3,5-tris[(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate, tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, 2-t-butyl-4-methyl-6-(2-acryloyloxy-3-t-butyl-5-methyl (4-hydroxyphenyl)phenol, 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4-8,10-tetraoxaspiro[5,5]undecane-bis[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], triethylene glycol bis[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], 1,1'-bis(4-hydroxyphenyl)cyclohexane, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methyl ethylenebis(4-ethyl-6-t-butylphenol), 2,2'-methylenebis(6-(1-methylcyclohexyl)-4-methylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 3,9-bis(2-(3-t-butyl-4-hydroxy-5-methylphenylpropionyloxy)1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro(5,5)undecane, 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-bis(3,5- Di-t-butyl-4-hydroxybenzyl) sulfide, 4,4'-thiobis(6-t-butyl-2-methylphenol), 2,5-di-t-butylhydroquinone, 2,5-di-t-amylhydroquinone, 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2,4-dimethyl-6-(1-methylcyclohexyl, styrenated phenol, 2,4-bis((octylthio)methyl)-5-methylphenol, etc.

Phosphorus-based antioxidants include bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl phosphite), tetrakis(2,4-di-t-butyl-5-methylphenyl)-4,4'-biphenylene diphosphonite, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, bis-(2,6-dicumylphenyl)pentaerythritol diphosphite, and 2,2-methylene biphosphonate. Examples include bis(4,6-di-t-butylphenyl)octyl phosphite, tris(mixed mono- and di-nonylphenyl phosphite), bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methoxycarbonylethyl-phenyl)pentaerythritol diphosphite, and bis(2,6-di-t-butyl-4-octadecyloxycarbonylethylphenyl)pentaerythritol diphosphite.

Examples of thioether antioxidants include dilauryl-3,3'-thiodipropionate, bis(2-methyl-4-(3-n-dodecyl)thiopropionyloxy)-5-t-butylphenyl) sulfide, distearyl-3,3'-thiodipropionate, and pentaerythritol-tetrakis(3-lauryl)thiopropionate.

(Preparation of Photosensitive Resin Composition)
The method for preparing the photosensitive resin composition in this embodiment is not limited, and any known method can be used depending on the components contained in the photosensitive resin composition.
For example, the above components can be mixed and dissolved in a solvent to prepare the composition.

(Photosensitive resin composition, cured film)
The photosensitive resin composition according to this embodiment is used by applying the photosensitive resin composition to a surface containing a metal such as Al or Cu, then pre-baking to dry the composition and form a resin film, then exposing and developing the composition to pattern the resin film into a desired shape, and then post-baking the resin film to harden it and form a hardened film.

When producing the permanent film, the pre-baking conditions can be, for example, a heat treatment at a temperature of 50°C to 150°C for 30 seconds to 1 hour. The post-baking conditions can be, for example, a heat treatment at a temperature of 150°C to 250°C for 30 minutes to 10 hours.

The viscosity of the photosensitive resin composition according to this embodiment can be appropriately set depending on the desired thickness of the resin film. The viscosity of the photosensitive resin composition can be adjusted by adding a solvent. During the adjustment, it is necessary to maintain a constant content of the urea compound and the non-cyclic amide compound in the solvent.

The upper limit of the viscosity of the photosensitive resin composition according to this embodiment may be, for example, 5000 mPa·s or less, 4000 mPa·s or less, or 3000 mPa·s or less. Furthermore, the lower limit of the viscosity of the photosensitive resin composition according to this embodiment may be, for example, 10 mPa·s or more, or 50 mPa·s or more, depending on the desired thickness of the resin film.

The film obtained from the photosensitive resin composition of this embodiment has a maximum elongation of 10 to 200%, preferably 20 to 150%, and an average elongation of 1 to 150%, preferably 2 to 120%, as measured by a tensile test using a Tensilon testing machine.
The film obtained from the photosensitive resin composition of this embodiment can have a tensile strength of 30 to 300 MPa, preferably 50 to 200 MPa.

As such, the photosensitive resin composition of this embodiment can provide cured products such as films with excellent mechanical strength. While the reason for this is unclear, it is presumed to be due to the excellent properties of the rigid polyimide of the present invention.

A film made from the photosensitive resin composition of this embodiment has an excellent low dielectric loss tangent, with a dielectric loss tangent (tanδ) measured at a frequency of 10 GHz of 0.008 or less, preferably 0.007 or less, and more preferably 0.006 or less.

Films made from the photosensitive resin composition of this embodiment have reduced cure shrinkage and can have a linear thermal expansion coefficient (CTE) of 200 ppm/°C or less, preferably 150 ppm/°C or less.

(Application)
The photosensitive resin composition (negative photosensitive resin composition) of this embodiment is used to form a resin film for semiconductor devices, such as a permanent film or a resist. Among these, it is preferably used in applications using a permanent film, from the viewpoint of achieving a good balance between improving the adhesion between the photosensitive resin composition and an Al pad after pre-baking and suppressing the generation of residues of the photosensitive resin composition during development, improving the adhesion between a cured film of the photosensitive resin composition and metal after post-baking, and also improving the chemical resistance of the photosensitive resin composition after post-baking.

In this embodiment, the resin film includes a cured film of a photosensitive resin composition. In other words, the resin film in this embodiment is formed by curing a photosensitive resin composition.

The permanent film is made of a resin film obtained by pre-baking, exposing, and developing a photosensitive resin composition, patterning it into the desired shape, and then post-baking it to harden it. The permanent film can be used as a protective film, interlayer film, dam material, etc. in semiconductor devices.

The resist is composed of a resin film obtained by applying a photosensitive resin composition to an object to be masked by the resist by a method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, and then removing the solvent from the photosensitive resin composition.
An example of a semiconductor device according to this embodiment is shown in FIG.

The semiconductor device 100 according to this embodiment can be a semiconductor device that includes the resin film described above. Specifically, in the semiconductor device 100, one or more of the group consisting of the passivation film 32, the insulating layer 42, and the insulating layer 44 can be a resin film that includes the cured product of this embodiment. Here, the resin film is preferably a permanent film as described above.

The semiconductor device 100 is, for example, a semiconductor chip. In this case, a semiconductor package is obtained by mounting the semiconductor device 100 on a wiring substrate via bumps 52.

The semiconductor device 100 includes a semiconductor substrate on which semiconductor elements such as transistors are provided, and a multilayer wiring layer (not shown) provided on the semiconductor substrate. The uppermost layer of the multilayer wiring layer includes an interlayer insulating film 30 and a top-layer wiring 34 provided on the interlayer insulating film 30. The top-layer wiring 34 is made of, for example, aluminum (Al). A passivation film 32 is provided on the interlayer insulating film 30 and the top-layer wiring 34. An opening is provided in part of the passivation film 32, exposing the top-layer wiring 34.

A redistribution layer 40 is provided on the passivation film 32. The redistribution layer 40 has an insulating layer 42 provided on the passivation film 32, redistribution 46 provided on the insulating layer 42, and an insulating layer 44 provided on the insulating layer 42 and the redistribution 46. An opening connected to the top-layer wiring 34 is formed in the insulating layer 42. The redistribution 46 is formed on the insulating layer 42 and in an opening provided in the insulating layer 42, and is connected to the top-layer wiring 34. An opening connected to the redistribution 46 is formed in the insulating layer 44.

Bumps 52 are formed in the openings provided in the insulating layer 44 via, for example, an under bump metallurgy (UBM) layer 50. The semiconductor device 100 is connected to a wiring board or the like via the bumps 52, for example.
Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

[Synthesis Example 1]
Synthesis of 1-[4-(5-2-norbornyl)butyl]-3,4-dimethyl-pyrrole-2,5-dione (NBBuDMMI)
In a 500 mL round-bottom flask, dimethylmaleic anhydride (42.6 g, 0.34 mol) was dissolved in toluene (300 mL) at room temperature. The solution was placed under a nitrogen atmosphere to remove oxygen. The reaction flask was placed in an ice bath to prevent excessive heating from the exothermic reaction. Once the dimethylmaleic anhydride was dissolved, a dropping funnel containing 5-norbornene-2-butylamine (49.6 g, 0.30 mol) was attached, and the norbornene compound was added dropwise to the reaction flask over a period of 3 hours. The dropping funnel was removed, and the flask was fitted with a Dean-Stark tube and reflux condenser. The solution was heated to reflux in an oil bath set at 125°C, and the reaction was stirred at that temperature for 18 hours. Approximately 6 mL of water was collected in the Dean-Stark tube during this time. The flask was removed from the oil bath and allowed to cool to room temperature. The toluene solvent was removed using an evaporator, yielding a yellow oil. The crude product was loaded onto a flash chromatography column (250 g of silica gel) and eluted with 1.7 L of a solvent mixture of cyclohexane/ethyl acetate (95/5 wt ratio). The elution solvent was removed using an evaporator, and the column was then dried under vacuum at 45°C for 18 hours to obtain 80.4 g (92.7% yield) of the desired product. The reaction scheme is shown below.

[Hansen Solubility Parameters of Solvents]
The Hansen solubility parameters of solvents and mixed solvents were obtained from the database of the computer software HSPiP or by inputting the molecular structure into the DIY program of the computer software HSPiP. For mixed solvents, the solubility parameter was calculated using the following formula:
In the following formula, the volume ratio of solvent 1 is represented by a, the Hansen solubility parameter is represented by the dispersion term (δD1), polarization term (δP1), and hydrogen bonding term (δH1), the volume ratio of solvent 2 is represented by b, and the Hansen solubility parameter is represented by the dispersion term (δD2), polarization term (δP2), and hydrogen bonding term (δH2).
Table 1 shows the dispersion term (δD), polarization term (δP), and hydrogen bond term (δH) of the polymer (pNBBuDMMI), solvent, and mixed solvent, and Table 2 shows the Hansen distance Ra between the polymer (pNBBuDMMI) and the mixed solvent.

[Hansen Solubility Parameters of Polynorbornene (pNBBuDMMI)]
The Hansen solubility parameter a of polynorbornene was measured by the following method. The polynorbornene used in the following measurements was the homopolymer of NBBuDMMI obtained in Synthesis Example 1. The dispersion parameter (δD), polarization parameter (δP), and hydrogen bond parameter (δH) of polynorbornene are not affected by the weight-average molecular weight of the polynorbornene.
[method]
To a 5 ml glass container, 0.05 g of polynorbornene is added with 1 ml of any solvent selected from the evaluation solvents listed below, and the mixture is stirred for 1 hour using a mix rotor. The dispersibility is then visually evaluated using the following three-point scale. All evaluation solvents and the evaluation results for dispersibility in each solvent are entered into the Sphere program of the computer software HSPiP (version 5.2.02), and the Hansen solubility parameter is calculated.
(Solvent for evaluation)
Hexane, cyclohexane, toluene, benzyl benzoate, propylene carbonate, 1-hexene, methyl ethyl ketone, acetone, acetonitrile, ethyl acetate, propylene glycol monomethyl ether acetate, cyclohexanol, isopropyl alcohol, methanol (Evaluation)
1: Completely dissolved.
2: Partially dissolved.
6: Does not dissolve.

As a result of the measurement, the dispersion term (δD) of the Hansen solubility parameters of polynorbornene was 18.9 MPa ^1/2 , the polarization term (δP) was 5.5 MPa ^1/2 , and the hydrogen bond term (δH) was 7.2 MPa ^1/2 .
Table 1 shows the dispersion parameter (δD), polarization parameter (δP), and hydrogen bonding parameter (δH) of polynorbornene (pNBBuDMMI) and the solvent, and Table 2 shows the difference between the Hansen solubility parameter a of polynorbornene (pNBBuDMMI) and the Hansen solubility parameter b of the solvent.

[Example 1]
Synthesis of Polynorbornene 1: After nitrogen purging for 1 hour, a suitable-sized reaction vessel equipped with a stirrer and condenser was charged with 1-[4-(5-2-norbornyl)butyl]-3,4-dimethyl-pyrrole-2,5-dione (NBBuDMMI) (24.60 g, 90 mmol) and triethylsilane (3.14 g, 27 mmol). Cyclopentyl methyl ether (CPME) (16.04 g) and ethyl acetate (EA) (1.98 g) were then added to obtain a reaction solution. The reaction solution was heated to 70°C with stirring under a nitrogen flow (50 mL/min). A catalyst (palladium (II) (acetonitrile) bis(triisopropylphosphine) acetate tetrakis(2,3,4,5,6-pentafluorophenyl)borate, Pd-1206) (0.0434 g) and a co-catalyst (N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, DANFABA) (0.0288 g) were dissolved in ethyl acetate (EA) (3.37 g) to prepare a solution, which was then added to the reaction solution so that the molar ratio of NBBuDMMI:catalyst:co-catalyst was 2500:1:1. Polymerization was then carried out at 70°C for 3 hours, and after polymerization, the mixture was allowed to cool to terminate the reaction.
The obtained polymerization solution was diluted with tetrahydrofuran to prepare a diluted solution, and then the diluted solution was added dropwise to a methanol solution to precipitate a white solid. The obtained white solid was collected and vacuum dried at a temperature of 50°C to obtain 20.02 g of a polymer (polynorbornene 1).
The toluene content of Polynorbornene 1 measured by the method described below was below the detection limit.

[Example 2]
Synthesis of Polynorbornene 2 Polynorbornene 2 was synthesized in the same manner as in Example 1 under the conditions shown in Table 3 below, except that CPME in Example 1 was replaced with 4-methyltetrahydropyran (MTHP).
The toluene content of Polynorbornene 2 measured by the method described below was below the detection limit.

[Example 3]
Synthesis of Polynorbornene 3 Polynorbornene 3 was synthesized in the same manner as in Example 1 under the conditions in Table 3 below, except that CPME in Example 1 was changed to cyclohexane (CH).
The toluene content of Polynorbornene 3 measured by the method described below was below the detection limit.

[Example 4]
Synthesis of Polynorbornene 4 Polynorbornene 4 was synthesized in the same manner as in Example 1 under the conditions shown in Table 3 below, except that CPME in Example 1 was changed to methylcyclohexane (MCH).
The toluene content of Polynorbornene 4 measured by the method described below was below the detection limit.

[Example 5]
Synthesis of Polynorbornene 5 Polynorbornene 5 was synthesized in the same manner as in Example 1 under the conditions shown in Table 3 below.
The toluene content of Polynorbornene 5 measured by the method described below was below the detection limit.

[Comparative Example 1]
Synthesis of Polynorbornene 6 Polynorbornene 6 was synthesized in the same manner as in Example 1 under the conditions shown in Table 3 below, except that cyclopentyl methyl ether in Example 1 was replaced with toluene (Tol).
The toluene content of Polynorbornene 6 measured by the method described below was 350 ppm.
The polynorbornenes obtained in all Examples did not contain trifluorotoluene.

(Weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (PDI))
In Synthesis Example 1, the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (PDI: Mw/Mn) are polystyrene-equivalent values obtained from a calibration curve of standard polystyrene (PS) obtained by GPC measurement. The measurement conditions are as follows:
Tosoh gel permeation chromatography device HLC-8320GPC
Column: TSK-GEL Supermultipore HZ-M manufactured by Tosoh Corporation
Detector: RI detector for liquid chromatography Measurement temperature: 40°C
Solvent: THF
Sample concentration: 5.0 mg/milliliter

(Conversion rate)
In Examples 1 to 5 and Comparative Example 1, the conversion of NBBuDMMI was determined by sampling the reaction solution before and after polymerization and measuring it by gas chromatography (GC). The measurement conditions were as follows:
Shimadzu gas chromatography device GC-2030
Column: SH-Rxi-1HT
Detector: FID
Measurement conditions: 210°C (30 minutes)
Internal standard: methyl amyl ketone Dilution solvent: mesitylene Sample concentration: 5.0 mg/ml

(Toluene content)
In Examples 1 to 5 and Comparative Example 1, the toluene content was determined by measuring the content of purified polynorbornene by gas chromatography mass spectrometry (GC/MS). The detection limit was approximately 10 ppm or less.
Column: F-Lab UA5-30M (0.25 mm x 30 m, film thickness: 250 mm)
Carrier gas: He, 1 ml/min Column temperature: 40°C (5 min) → 10°C/min → 300°C (9 min)
Detector: MS
Inlet temperature: 210℃
Split ratio: 50:1
Sample weight: 2.0 mg
Ion source: EI, m/z 25-800

[Synthesis Example 1]
(Synthesis of Polyimide)
In the synthesis of the following polyimides, the following compounds were used:
4,4-diamino-3,3-diethyl-5,5-dimethyldiphenylmethane (hereinafter also referred to as MED-J) represented by the following formula:

4-[4-(1,3-dioxoisobenzofuran-5-ylcarbonyloxy)-2,3,5-trimethylphenyl]-2,3,6-trimethylphenyl 1,3-dioxoisobenzofuran-5-carboxylate (hereinafter also referred to as TMPBP-TME) represented by the following formula:

First, 43.99 g (155.8 mmol) of MED-J and 89.22 g (144.2 mmol) of TMPBP-TME were placed in an appropriately sized reaction vessel equipped with a stirrer and a condenser, followed by the addition of 399.64 g of γ-butyrolactone (hereinafter also referred to as GBL).
After bubbling nitrogen for 10 minutes, the temperature was raised to 60°C while stirring, and the reaction was carried out for 1 hour. A solution of 8.73 g (69.2 mmol) of dimethyl maleic anhydride in 26.19 g of gamma-butyrolactone was prepared in advance, and this solution was added to the reaction vessel and reacted for an additional 30 minutes. The reaction was further carried out at 175°C for 3 hours, whereby the diamine and acid anhydride were polymerized and the ends were capped, producing a polymerized solution.
The obtained polymerization solution was diluted with tetrahydrofuran to prepare a diluted solution, and then the diluted solution was added dropwise to a methanol solution to precipitate a white solid. The obtained white solid was collected and vacuum dried at a temperature of 80° C. to obtain 125.88 g of polyimide.
GPC measurement of the polyimide revealed that the weight average molecular weight Mw was 74,000, the polydispersity index (weight average molecular weight Mw/number average molecular weight Mn) was 2.62, and the end-capping rate was 65%.
The polyimide obtained contained a repeating unit represented by the following formula in part and had a dimethylmaleimide group at the end.

[Example 6]
The following photosensitive resin compositions were prepared using the following components:
Photosensitizer: 1-chloro-4-propoxythioxanthone (SPEEDCURE CPTX (trade name) manufactured by Lambson, UK)
Solvent: Cyclopentanone Adhesion aid: 3-trimethoxysilylpropylsuccinic anhydride (manufactured by Shin-Etsu Chemical Co., Ltd., product name "X-12-967C")
The components shown in Table 4 were mixed to prepare photosensitive resin compositions.
The obtained photosensitive resin composition was spin-coated onto the surface of a silicon wafer so that the film thickness after drying would be 10 μm. After pre-baking at 120° C. for 4 minutes, the coating was exposed to 1500 mJ/ ^cm2 using a high-pressure mercury lamp, and then cured at 200° C. for 120 minutes in a nitrogen atmosphere to prepare a film.

[Polymer compatibility (compatibility of polynorbornene with polyimide)]
The photosensitive resin composition thus obtained was prebaked at 120° C. for 4 minutes, and then the surface was visually inspected under a fluorescent lamp to determine whether it was cloudy or not, and evaluated according to the following criteria.
◯: Compatible.
×: Not compatible.

(Dielectric tangent Df)
The photosensitive resin composition of Example 6 was applied to a substrate, the coating was dried at 120°C for 10 minutes, exposed to PLA (540 mJ), and cured at 200°C for 2 hours in a nitrogen atmosphere to obtain a film with a thickness of 100 μm. The dielectric loss tangent of the obtained film at 10 GHz was measured by a cavity resonator method.

[Evaluation of patterning characteristics]
It was confirmed in the following manner that the photosensitive resin composition of Example 6 could be sufficiently patterned by exposure and development.
The photosensitive resin composition of Example 6 was applied onto an 8-inch silicon wafer using a spin coater. After application, the wafer was prebaked on a hot plate in the atmosphere at 120° C. for 4 minutes to obtain a coating film with a thickness of approximately 8.0 μm.
The coating film was irradiated with i-line through a mask on which a 20 μm wide via pattern was drawn using an i-line stepper (Nikon Corporation, NSR-4425i).
After the exposure, the film was spray-developed for 120 seconds using cyclopentanone as a developer to dissolve and remove the unexposed areas, thereby obtaining a via pattern.
The cross section of the obtained via pattern was observed using a tabletop SEM. The width at the midpoint between the bottom surface and the opening of the via pattern was taken as the via width, and was evaluated according to the following criteria.
Good patterning properties: 20 μm via pattern opened. Poor patterning properties: 20 μm via pattern not opened. The coating film obtained from the photosensitive resin composition of Example 6 had good patterning properties.

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

Claims (12)

The method includes a step of polymerizing a norbornene-based compound in a solvent in the presence of a palladium catalyst and a chain transfer agent to obtain polynorbornene,
The solvent does not contain toluene and trifluorotoluene or contains toluene and trifluorotoluene at levels below the detection limit in GC/MS measurement,
The solvent is substantially one solvent selected from the group consisting of ether solvents, hydrocarbon solvents containing no aromatic ring, and ethyl acetate, or a mixed solvent of two or more solvents;
The method for producing polynorbornene, wherein the difference between the Hansen solubility parameter a of the polynorbornene and the Hansen solubility parameter b of the solvent is 8 MPa ^1/2 or less. The method for producing polynorbornene according to claim 1 , wherein the norbornene-based compound includes a compound represented by the following general formula (1):
(In general formula (1), ^R1 and ^R2 each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; ^Q1 represents a single bond or a divalent organic group; ^G1 , ^G2 , and ^G3 each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms; and m is 0, 1, or 2.) 3. The method for producing polynorbornene according to claim 1, wherein the chain transfer agent comprises at least one selected from the group consisting of a compound represented by the following general formula (a), formic acid, and oxalic acid:
(In general formula (a), R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.) 4. The method for producing polynorbornene according to claim 3, wherein in general formula ( a ), R ₁ , R ₂ and R ₃ each independently represent an alkyl group having 1 to 3 carbon atoms. The method for producing polynorbornene described in any one of claims 1 to 4, wherein the solvent is a mixed solvent of two or more types. The method for producing polynorbornene described in any one of claims 1 to 5, wherein the solvent includes at least one selected from the group consisting of ether-based solvents and hydrocarbon-based solvents that do not contain aromatic rings. the ether-based solvent includes at least one selected from cyclopentyl methyl ether and methyl tetrahydropyran;
The method for producing polynorbornene according to claim 6 , wherein the hydrocarbon solvent not containing an aromatic ring comprises at least one selected from cyclohexane and methylcyclohexane. 8. The method for producing polynorbornene according to claim 1, wherein when the solvent is a mixed solvent of two types of solvents, the difference between the Hansen solubility parameter a of the norbornene-based compound and the Hansen solubility parameter c of the mixed solvent of the two types of solvents is 8 MPa ^1/2 or less. The method for producing polynorbornene described in any one of claims 1 to 8, wherein the solvent is a mixed solvent of ethyl acetate and at least one selected from cyclopentyl methyl ether, methyltetrahydropyran, cyclohexane, and methylcyclohexane. The method for producing polynorbornene described in any one of claims 1 to 9, wherein the palladium catalyst is used in an amount of 1/5000 mole or more and 1/2000 mole or less per mole of the norbornene-based compound. The method for producing polynorbornene according to any one of claims 1 to 9 further comprises a step of mixing the polynorbornene obtained in the polymerization step with a poor solvent for the polynorbornene to reprecipitate the powdery polynorbornene. The method for producing polynorbornene described in claim 11, further comprising a step of diluting the polynorbornene obtained in the polymerization step prior to the reprecipitation step.