JP2018124502A - Photosensitive resin composition, resin film prepared therewith, and electronic apparatus including resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition that is prepared into a resin film that has improved heat resistance and chemical resistance.SOLUTION: A photosensitive resin composition has a copolymer, a crosslinker, and a photosensitizer, where, the copolymer has: a structural unit derived from a norbornene monomer; and at least one structural unit selected from the group consisting of maleic anhydride, a maleic anhydride derivative, maleimide and a maleimide derivative. At least one terminal of the copolymer has a functional group to react with the crosslinker.SELECTED DRAWING: None

Description

  The present invention relates to a photosensitive resin composition, a resin film formed thereby, and an electronic device including the resin film.

  Until now, in the field of photosensitive resin compositions, various techniques have been developed for the purpose of increasing the accuracy of resist patterns accompanying the miniaturization of patterns. As this type of technology, for example, the technology described in Patent Document 1 can be cited. This document describes a radiation-sensitive resin composition containing a specific polymer and a specific acid generator. The polymer is N- (t-butyloxycarbonylmethyl) maleimide, N- (1-methyl-1-cyclopentyloxycarbonylmethyl) maleimide, or N- (2-ethyl-2-adamantyloxycarbonylmethyl). By having the structural unit (I) that is maleimide and the structural unit (II) that is 2-norbornene, it is excellent in LWR (Line Width Roughness) performance and defect suppression, which indicates a small variation in line width. (Patent Document 1).

  Patent Document 1 describes that AIBN (azobisisobutyronitrile) is used as a radical polymerization initiator for the synthesis of the polymer (Examples 1 to 3 in Patent Document 1).

JP-A-2015-184458

  However, as a result of the study of the heat resistance and chemical resistance of the photosensitive resin composition by the present inventor, the radiation sensitive resin composition described in Patent Document 1 is further improved from the viewpoint of heat resistance and chemical resistance. It turns out that there is room for improvement. This invention makes it a subject to provide the photosensitive resin composition which improved heat resistance and chemical resistance, when it was set as the resin film.

This inventor considered introducing the molecular structure which contributes to bridge | crosslinking into the molecular structure of a copolymer, and improving the heat resistance and chemical resistance of a photosensitive resin composition.
Therefore, as a result of studying the conventional copolymer by the present inventor, it was found that it is effective to introduce a functional group that reacts with a crosslinking agent at the terminal of the copolymer.
As a result, it was found that reacting these functional groups with a crosslinking agent to form a crosslinked structure via the crosslinking agent contributes to improvement in heat resistance and chemical resistance of the photosensitive resin composition, The present invention has been completed.

According to the present invention,
A copolymer represented by the following general formula (1);
A crosslinking agent;
A photosensitizer,
A photosensitive resin composition is provided.

（一般式（１）中、
ｌおよびｍはそれぞれ、共重合体中における、Ａ及びＢのモル含有率を示し、
ｌ＋ｍ＝１であり、
Ａは下記一般式（Ａ１）または一般式（Ａ２）により示される構造単位の１種以上を含み、
Ｂは下記一般式（Ｂ１）、一般式（Ｂ２）、式（Ｂ３）、式（Ｂ４）、式（Ｂ５）または一般式（Ｂ６）により示される構造単位の１種以上を含み、
Ｘは前記架橋剤と反応する官能基を含む炭素数１以上３０以下の有機基であり、
Ｙは水素または炭素数１以上３０以下の有機基である。）

(In general formula (1),
l and m respectively represent the molar contents of A and B in the copolymer;
l + m = 1,
A includes one or more structural units represented by the following general formula (A1) or general formula (A2),
B includes one or more structural units represented by the following general formula (B1), general formula (B2), formula (B3), formula (B4), formula (B5), or general formula (B6),
X is an organic group having 1 to 30 carbon atoms including a functional group that reacts with the crosslinking agent,
Y is hydrogen or an organic group having 1 to 30 carbon atoms. )

（一般式（Ａ１）中、Ｒ_１、Ｒ_２、Ｒ_３およびＲ_４はそれぞれ独立して水素または炭素数１以上３０以下の有機基である。ただし、カルボキシル基を除く。
ａ_１は０、１または２である。）

(In general formula (A1), R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen or an organic group having 1 to 30 carbon atoms, except for a carboxyl group.
a ₁ is 0, 1 or 2. )

（一般式（Ａ２）中、Ｒ_５、Ｒ_６、Ｒ_７およびＲ_８はそれぞれ独立して水素または炭素数１以上３０以下の有機基であって、
Ｒ_５、Ｒ_６、Ｒ_７およびＲ_８に少なくとも１つのカルボキシル基を含み、
ａ_２は０、１または２である。）

(In the general formula (A2), R ₅ , R ₆ , R ₇ and R ₈ are each independently hydrogen or an organic group having 1 to 30 carbon atoms,
R ₅ , R ₆ , R ₇ and R ₈ contain at least one carboxyl group,
a ₂ is 0, 1 or 2. )

（一般式（Ｂ１）中、Ｒ_９は、炭素数１以上３０以下の有機基である。）

(In General Formula (B1), R ₉ is an organic group having 1 to 30 carbon atoms.)

（一般式（Ｂ２）中、Ｒ_１０及びＲ_１１は、それぞれ独立して炭素数１以上３０以下の有機基である。）

(In General Formula (B2), R ₁₀ and R ₁₁ are each independently an organic group having 1 to 30 carbon atoms.)

（一般式（Ｂ６）中、Ｒ_１２は炭素数１以上３０以下の有機基である。）

(In the general formula (B6), R ₁₂ is an organic group having 1 to 30 carbon atoms.)

  Moreover, according to this invention, the resin film which consists of the said photosensitive resin composition is provided.

  Furthermore, according to this invention, an electronic device provided with the said resin film is provided.

  According to the present invention, a photosensitive resin composition having improved heat resistance and chemical resistance when used as a resin film is provided.

It is sectional drawing which shows an example of the electronic device which concerns on this embodiment.

  Hereinafter, the present embodiment will be described with reference to the drawings as appropriate. In all the drawings, the same symbols are attached to the same components, and the description thereof is omitted.

  The photosensitive resin composition according to the present embodiment includes a copolymer having a specific structure, a crosslinking agent, and a photosensitive agent.

  In the field of photosensitive resin compositions for forming resin films used in electronic devices, various characteristics are required for photosensitive resin compositions. For example, an electronic device using a resin film as a rewiring layer is required to improve the heat resistance and chemical resistance of the rewiring layer from the viewpoint of improving the reliability of the electronic device. Therefore, the photosensitive resin film for forming such a resin film is required to improve heat resistance and chemical resistance.

Here, as the copolymer used in the photosensitive resin composition, at least one selected from the group consisting of a structural unit derived from a norbornene-type monomer, and maleic anhydride, a maleic anhydride derivative, a maleimide, and a maleimide derivative. There are copolymers containing structural units. The inventor examined the molecular structure of the copolymer in order to further improve the heat resistance and chemical resistance of the photosensitive resin composition containing the copolymer.
First, the inventor considered introducing a carboxyl group into a side chain of a structural unit derived from some norbornene monomers. That is, it was considered that the copolymer contains a structural unit derived from a norbornene-type monomer containing a carboxyl group in the side chain. And in the photosensitive resin composition containing the said copolymer, a crosslinking agent, and a photosensitive agent, it tried to make the carboxyl group of the said copolymer react with a crosslinking agent, and to form a crosslinked structure. By forming such a crosslinked structure, it was estimated that the crosslinking density in the photosensitive resin composition can be increased and the heat resistance and chemical resistance can be improved.
However, in the copolymer, the heat resistance and chemical resistance of the photosensitive resin composition are still insufficient with respect to the required level simply by forming a crosslinked structure in the side chain of the structural unit derived from the norbornene-type monomer. Met. Although the detailed mechanism is not clear, when a cross-linked structure is formed in the side chain of the structural unit derived from the norbornene type monomer, it is presumed that the steric hindrance of the molecular orbital derived from the norbornene type structure occurs. Thereby, it is thought that the molecular chain of a copolymer is not restrained appropriately by a crosslinked structure from a viewpoint of improving heat resistance and chemical resistance.
Then, when this inventor examined further about the molecular structure of the said copolymer, it discovered that heat resistance and chemical-resistance could be improved by providing the functional group which has active hydrogen in the terminal of copolymerization.

The photosensitive resin composition which concerns on this embodiment contains a copolymer, a crosslinking agent, and a photosensitive agent, and the terminal of a copolymer contains the functional group which reacts with a crosslinking agent here. The copolymer includes a structural unit derived from a norbornene-type monomer and one or more structural units selected from the group consisting of maleic anhydride, a maleic anhydride derivative, a maleimide and a maleimide derivative.
In the photosensitive resin composition according to this embodiment, the reason why the heat resistance and chemical resistance are improved is not clear, but is presumed as follows. It is presumed that the functional group at the terminal of the copolymer reacts with the crosslinking agent to form a crosslinked structure while alleviating steric hindrance due to the norbornene type structural unit of the copolymer. Thereby, the molecular chain of the copolymer is firmly bound. Therefore, the micro brown motion of the molecular chain of the copolymer is suppressed, and the heat resistance of the photosensitive resin composition is improved. Further, the cross-linked structure is formed densely, so that chemical molecules such as a solvent are prevented from entering the copolymer, and the reactivity between the photosensitive resin composition and the chemical is lowered. As mentioned above, it is estimated that the photosensitive resin composition of this embodiment can improve heat resistance and chemical resistance.

  Hereinafter, each component of the photosensitive resin composition of this embodiment is demonstrated.

(Copolymer)
First, the copolymer according to this embodiment will be described.
The copolymer according to this embodiment is represented by the following general formula (1).

（一般式（１）中、
ｌおよびｍはそれぞれ、共重合体中における、Ａ及びＢのモル含有率を示し、
ｌ＋ｍ＝１であり、
Ａは下記一般式（Ａ１）または一般式（Ａ２）により示される構造単位の１種以上を含み、
Ｂは下記一般式（Ｂ１）、一般式（Ｂ２）、式（Ｂ３）、式（Ｂ４）、式（Ｂ５）または一般式（Ｂ６）により示される構造単位の１種以上を含み、
Ｘは前記架橋剤と反応する官能基を含む炭素数１以上３０以下の有機基であり、
Ｙは水素または炭素数１以上３０以下の有機基である。）

(In general formula (1),
l and m respectively represent the molar contents of A and B in the copolymer;
l + m = 1,
A includes one or more structural units represented by the following general formula (A1) or general formula (A2),
B includes one or more structural units represented by the following general formula (B1), general formula (B2), formula (B3), formula (B4), formula (B5), or general formula (B6),
X is an organic group having 1 to 30 carbon atoms including a functional group that reacts with the crosslinking agent,
Y is hydrogen or an organic group having 1 to 30 carbon atoms. )

  The arrangement | sequence of the said copolymer is not limited, A random copolymer, an alternating copolymer, a block copolymer, a periodic copolymer, etc. can be selected.

  The composition ratio of the structural unit A to the structural unit B will be described in the copolymer. In the copolymer, when the molar content (mol%) of the structural unit A is 1 and the molar content (mol%) of the structural unit B is m and l + m = 1, for example, a numerical value of 1 The range is preferably 0.1 ≦ l ≦ 0.9. The numerical range of m is preferably 0.1 ≦ m ≦ 0.9.

In the copolymer represented by the general formula (1), A is a structural unit derived from a norbornene-type monomer having no carboxyl group in the side chain, represented by the following general formula (A1), or the following general formula (A2) represented by a structural unit derived from a norbornene-type monomer having at least one carboxyl group in R ₅ to R _8.

A preferably contains a structural unit represented by the following general formula (A2). Thereby, the carboxyl group of side chain R < ₅ > -R < ₈ > of the following general formula (A2) and a crosslinking agent can be made to react. Therefore, in addition to the cross-linked structure at the end of the copolymer, a cross-linked structure is formed through the carboxyl group in the side chain. Thereby, a crosslinking density can be improved, reducing a steric hindrance and forming a suitable crosslinked structure. Therefore, the heat resistance and chemical resistance of the photosensitive resin composition can be improved.
A further preferably includes a structural unit represented by the following general formula (A1) and a structural unit represented by the following general formula (A2). Thereby, the acid value of a copolymer can be controlled and it becomes possible to implement | achieve arbitrary alkali solubility according to the characteristic of a desired copolymer or the photosensitive resin composition.

（一般式（Ａ１）中、Ｒ_１、Ｒ_２、Ｒ_３およびＲ_４はそれぞれ独立して水素または炭素数１以上３０以下の有機基である。ただし、カルボキシル基を除く。
ａ_１は０、１または２である。）

(In general formula (A1), R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen or an organic group having 1 to 30 carbon atoms, except for a carboxyl group.
a ₁ is 0, 1 or 2. )

（一般式（Ａ２）中、Ｒ_５、Ｒ_６、Ｒ_７およびＲ_８はそれぞれ独立して水素または炭素数１以上３０以下の有機基であって、
Ｒ_５、Ｒ_６、Ｒ_７およびＲ_８に少なくとも１つのカルボキシル基を含み、
ａ_２は０、１または２である。）

(In the general formula (A2), R ₅ , R ₆ , R ₇ and R ₈ are each independently hydrogen or an organic group having 1 to 30 carbon atoms,
R ₅ , R ₆ , R ₇ and R ₈ contain at least one carboxyl group,
a ₂ is 0, 1 or 2. )

In the present embodiment, R _{1 to} R ₄ in the general formula (A1) and R _{5 to} R ₈ in the general formula (A2) are hydrogen or an organic group having 1 to 30 carbon atoms. Each independently may contain one or more atoms selected from O, N, S, P and Si in the structure.
Furthermore, in this embodiment, the organic group which comprises R < ₁ >, R < ₂ >, R < ₃ > and R < ₄ > does not have any acidic functional group. Thereby, the control of the acid value in the copolymer can be facilitated.

In this embodiment, R _{1 to} R ₄ in the general formula (A1) and R _{5 to} R ₈ in the general formula (A2) are each independently hydrogen or a carbon number of 1 to 30. An organic group, preferably hydrogen or an organic group having 1 to 15 carbon atoms, more preferably hydrogen or an organic group having 1 to 10 carbon atoms.

In this embodiment, examples of the organic group constituting R _{1 to} R ₄ in the general formula (A1) and R _{5 to} R ₈ in the general formula (A2) include an alkyl group, an alkenyl group, Examples include alkynyl group, alkylidene group, aryl group, aralkyl group, alkaryl group, cycloalkyl group, alkoxy group and heterocyclic group.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, An octyl group, a nonyl group, and a decyl group are mentioned. Examples of the alkenyl group include allyl group, pentenyl group, and vinyl group. An ethynyl group is mentioned as an alkynyl group. Examples of the alkylidene group include a methylidene group and an ethylidene group. Examples of the aryl group include a tolyl group, a xylyl group, a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the aralkyl group include a benzyl group and a phenethyl group. Examples of the alkaryl group include a tolyl group and a xylyl group. Examples of the cycloalkyl group include an adamantyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an s-butoxy group, an isobutoxy group, a t-butoxy group, an n-pentyloxy group, and a neopentyloxy group. , N-hexyloxy group. Examples of the heterocyclic group include an epoxy group and an oxetanyl group.

In the present embodiment, a ₁ in the general formula (A1) and a ₂ in the general formula (A2) are each independently 0, 1 or 2, and may be 0 or 1. It may be 0.

In the present embodiment, in the general formula (A1), the organic group constituting R ₁ , R ₂ , R _3, and R ₄ may include, for example, a carboxylic anhydride group. In this case, R ₁ or R ₂ and R ₃ or R ₄ are preferably bonded via a carboxylic anhydride group to form a cyclic structure via the carboxylic anhydride group.

When the general formula (A1) has a cyclic structure through the carboxylic acid anhydride described above, a part of the cyclic structure is opened by hydrolysis to form a carboxyl group, and the general formula (A2) ). Thereby, the quantity of the carboxyl group in the side chain of the structural unit derived from the norbornene-type monomer of a copolymer can be adjusted. Therefore, a more appropriate cross-linked structure can be formed.
The specific hydrolysis method is not limited, and a conventionally known method can be used according to the cyclic structure through the carboxylic anhydride group. For example, the method of adding alcohol or water, such as methanol and ethanol, to the solution containing a copolymer, and heating is mentioned.

In this embodiment, at least one carboxyl group is contained in R ₅ , R ₆ , R ₇ and R ₈ in the general formula (A2). Thereby, the active hydrogen of a carboxyl group reacts with a crosslinking agent, and further forms a crosslinked structure in the copolymer. That is, in the copolymer, a crosslinked structure is formed in the side chain of the structural unit derived from the norbornene-type monomer as the main chain. Thereby, a crosslinking density can be improved. Therefore, heat resistance and chemical resistance can be further improved.

In the present embodiment, the number of carboxyl groups contained in R ₅ , R ₆ , R ₇ and R ₈ in the general formula (A2) is not limited, and may include at least one carboxyl group, Two or more carboxyl groups may be included. By appropriately adjusting the number of carboxyl groups, an arbitrary crosslinked structure can be formed, and by adjusting the acid value, arbitrary alkali solubility can be realized.

  In the copolymer represented by the general formula (1), B represents the following general formula (B1), the following general formula (B2), the following formula (B3), the following formula (B4), and the following formula (B5). Alternatively, one or more structural units represented by the following general formula (B6) are included.

（一般式（Ｂ１）中、Ｒ_９は、炭素数１以上３０以下の有機基である。）

(In General Formula (B1), R ₉ is an organic group having 1 to 30 carbon atoms.)

（一般式（Ｂ２）中、Ｒ_１０及びＲ_１１は、それぞれ独立して炭素数１以上３０以下の有機基である。）

(In General Formula (B2), R ₁₀ and R ₁₁ are each independently an organic group having 1 to 30 carbon atoms.)

（一般式（Ｂ６）中、Ｒ_１２は、炭素数１以上３０以下の有機基である。）

(In the general formula (B6), R ₁₂ is an organic group having 1 to 30 carbon atoms.)

  B preferably includes a structural unit represented by the above formula (B5) or the above general formula (B6), and B more preferably includes a structural unit represented by the above general formula (B6). Thereby, heat resistance and chemical resistance can be improved, and sensitivity can be maintained.

The organic group having 1 to 30 carbon atoms constituting R _{9 to} R ₁₂ in the general formula (B1), the general formula (B2), and the general formula (B6) has O, N, S, P in its structure. And may contain one or more atoms selected from Si.
Furthermore, in this embodiment, all of the organic groups constituting R _{9 to} R ₁₂ may not have an acidic functional group such as a carboxyl group. Thereby, the control of the acid value in the copolymer can be facilitated.

In the present embodiment, R _{9 to} R ₁₂ in the general formula (B1), the general formula (B2), and the general formula (B6) are each independently an organic group having 1 to 30 carbon atoms, The organic group is preferably an organic group having 1 to 15 carbon atoms, more preferably an organic group having 1 to 10 carbon atoms, and still more preferably an organic group having 1 to 6 carbon atoms.

In this embodiment, examples of the organic group constituting R _{9 to} R ₁₂ in the general formula (B1), general formula (B2), and general formula (B6) include an alkyl group, an alkenyl group, an alkynyl group, and an alkylidene. Group, aryl group, aralkyl group, alkaryl group, cycloalkyl group, alkoxy group and heterocyclic group.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, An octyl group, a nonyl group, and a decyl group are mentioned. Examples of the alkenyl group include allyl group, pentenyl group, and vinyl group. An ethynyl group is mentioned as an alkynyl group. Examples of the alkylidene group include a methylidene group and an ethylidene group. Examples of the aryl group include a tolyl group, a xylyl group, a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the aralkyl group include a benzyl group and a phenethyl group. Examples of the alkaryl group include a tolyl group and a xylyl group. Examples of the cycloalkyl group include an adamantyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an s-butoxy group, an isobutoxy group, a t-butoxy group, an n-pentyloxy group, and a neopentyloxy group. , N-hexyloxy group. Examples of the heterocyclic group include an epoxy group and an oxetanyl group.

  In the copolymer represented by the general formula (1), X is an organic group containing a functional group that reacts with the crosslinking agent. Thereby, a crosslinked structure can be formed in at least one terminal of the copolymer.

  In the copolymer represented by the general formula (1), X may be an organic group having 1 to 30 carbon atoms including a functional group that reacts with a crosslinking agent, and an organic group having 1 to 15 carbon atoms. Preferably an organic group having 1 to 10 carbon atoms, more preferably an organic group having 1 to 8 carbon atoms, and an organic group having 1 to 7 carbon atoms. Is particularly preferred.

Although it does not limit as a functional group which reacts with the crosslinking agent which X contains, It is preferable that it contains an active hydrogen. Thereby, without impairing the performance as the photosensitive resin composition, the functional group of X can cause a crosslinking reaction with the crosslinking agent, thereby forming a crosslinked structure.
The functional group containing active hydrogen contained in X is preferably a hydrophilic functional group. Thereby, the reactivity with a crosslinking agent can be exhibited appropriately. Therefore, a suitable cross-linked structure can be formed.
Specific examples of hydrophilic functional groups containing active hydrogen include carboxyl groups; amino groups such as primary amino groups and secondary amino groups; hydroxyl groups; nitrogen-containing heterocyclic groups such as imidazole groups and imidazoline groups; esters. And functional groups that form acidic groups by hydrolysis of groups, amide groups, and the like. One or more of these can be included.
Among these, it is preferable to include at least one selected from the group consisting of a carboxyl group, a primary amino group, a secondary amino group, a hydroxyl group, an imidazoline group, an ester group and an amide group. And more preferably one or more selected from the group consisting of secondary amino groups. Thereby, it becomes possible to raise | generate a crosslinking reaction with a crosslinking agent, maintaining the performance as a photosensitive resin composition. Moreover, when X contains a carboxyl group as a functional group that reacts with the crosslinking agent, the reactivity between the copolymer and the crosslinking agent can be adjusted. This is suitable in that an appropriate cross-linked structure can be produced and unreacted active hydrogen is not generated.

Here, X may include a structural unit derived from a radical polymerization initiator, or may be a structural unit derived from a radical polymerization initiator. This is because when synthesizing the copolymer represented by the general formula (1), when a radical polymerization initiator is used as the polymerization initiator, X can be formed from the structure of the radical polymerization initiator. It is. Thereby, the copolymer provided with arbitrary structures as X is compoundable by selecting arbitrary radical polymerization initiators.
In addition, it can be identified from the spectrum data of < ¹ > H-NMR measurement that X contains the structural unit derived from a radical polymerization initiator, for example.

The structure of X derived from the radical polymerization initiator is not limited, and specific examples include the following formula (X1) to the following formula (X5).
The structure derived from the radical polymerization initiator in X is one or more kinds represented by the group consisting of the following formula (X1), formula (X2), formula (X3), formula (X4) and formula (X5). It is preferable to contain. This is because the structure of the following formulas (X1) to (X5) contributes to cross-linking, so that steric hindrance can be more effectively mitigated, so that a stronger cross-linking structure can be formed. Guessed.
Among these, it is more preferable that the following formula (X1) or formula (X2) is included. Thereby, heat resistance and chemical resistance can be further improved.

  The structure represented by the formula (X1) can be formed, for example, by cleaving 4,4′-azobis (4-cyanovaleric acid), which is a radical polymerization initiator. The structure represented by the formula (X2) is formed by, for example, cleaving 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], which is a radical polymerization initiator. Can do. The structure represented by the above formula (X3) can be formed, for example, by cleaving 2,2′-azobis [N- (2-carboxyethyl) -2-methyl], which is a radical polymerization initiator. . The structure represented by the above formula (X4) can be formed, for example, by cleaving 2,2′-azobis (2-methylpropionamidine) which is a radical polymerization initiator. The structure represented by the formula (X5) can be formed, for example, by cleaving 2,2′-azobis [2- (2-imidazolin-2-yl) propane], which is a radical polymerization initiator. .

  In the copolymer represented by the general formula (1), Y is hydrogen or an organic group having 1 to 30 carbon atoms, preferably hydrogen or an organic group having 1 to 15 carbon atoms. It is more preferably an organic group having 1 to 10 carbon atoms, more preferably hydrogen or an organic group having 1 to 6 carbon atoms, and even more preferably hydrogen or an organic group having 1 to 4 carbon atoms. .

Y may include a structural unit derived from a radical polymerization initiator, hydrogen, or a structural unit derived from a chain transfer agent, and derived from a structural unit derived from a radical polymerization initiator, hydrogen, or a chain transfer agent. It may be a structural unit.
This is because when a copolymer represented by the general formula (1) is synthesized, when a radical polymerization initiator is used as a polymerization initiator, Y is formed by a radical chain reaction termination reaction that is a polymerization reaction of the copolymer. Because it can be done.

  The radical chain reaction termination reaction will be described. The termination reaction of the radical chain reaction is caused by a reaction mechanism called recombination termination or disproportionation termination at the growing end of the copolymer in the radical chain reaction, that is, at the radical portion of the growing copolymer. In the radical chain reaction, recombination termination and disproportionation termination compete with each other.

  The recombination termination is a termination reaction in which two radicals of the growing copolymer react with each other. Thereby, for example, when an n-mer-growing copolymer and an m-mer-growing copolymer cause recombination termination, an n + m-mer copolymer is formed and the radical chain reaction is stopped. . X and Y of the copolymer that has caused recombination termination contain a structural unit derived from a radical polymerization initiator. That is, in the copolymer in which the recombination is stopped, the structural unit derived from the radical polymerization initiator in Y is the same as the structural unit derived from the X radical polymerization initiator described above.

  The disproportionation stop is a stop reaction in which a radical of a growing copolymer moves to another growing copolymer or a molecule such as a solvent. Thereby, in the copolymer which caused disproportionation termination, X is a structural unit derived from the radical polymerization initiator described above, and Y is hydrogen.

Further, when a chain transfer agent is used during the synthesis of the copolymer, a chain transfer reaction occurs in the radical chain reaction that is a polymerization reaction. In the copolymer that has undergone a chain transfer reaction, X in the copolymer is a structural unit derived from the above-described radical polymerization initiator, and Y is a structural unit derived from the chain transfer agent.
In addition, it can confirm that Y is a structure derived from a chain transfer agent, for example by the relationship between the addition amount of a chain transfer agent, and a weight average molecular weight.

  In the copolymer represented by the general formula (1), Y may contain a functional group that reacts with the crosslinking agent. When Y contains a functional group that reacts with a crosslinking agent, a crosslinked structure can be formed at both ends of the copolymer. A copolymer that forms a crosslinked structure at both ends can form a stronger crosslinked structure as compared with a copolymer that contains a functional group that reacts with a crosslinking agent at one end. Thereby, heat resistance and chemical resistance can be improved.

  The functional group that reacts with the crosslinking agent contained in Y is not limited, but is preferably a functional group containing active hydrogen. Thereby, when X contains a functional group containing active hydrogen, the functional group and the cross-linking agent that react with the cross-linking agent contained in Y undergo a cross-linking reaction by the same reaction mechanism as that caused by the functional group of X and the cross-linking agent. Wake up. Therefore, uniform reactivity can be produced at both ends of the copolymer, and a crosslinked structure can be formed more firmly.

The functional group containing the active hydrogen of Y is preferably a hydrophilic functional group. Thereby, the reactivity with a crosslinking agent can be exhibited appropriately. Therefore, a suitable cross-linked structure can be formed.
Specific examples of hydrophilic functional groups containing active hydrogen include carboxyl groups; amino groups such as primary amino groups and secondary amino groups; hydroxyl groups; nitrogen-containing heterocyclic groups such as imidazole groups and imidazoline groups; ester groups; The functional group which forms an acidic group by hydrolysis, such as an amide group, can be mentioned. One or more of these can be included.
Among these, it is preferable to include at least one selected from the group consisting of a carboxyl group, a primary amino group, a secondary amino group, a hydroxyl group, an imidazoline group, an ester group and an amide group. And more preferably one or more selected from the group consisting of secondary amino groups. Thereby, it becomes possible to raise | generate a crosslinking reaction with a crosslinking agent, without impairing the performance as a photosensitive resin composition. Moreover, when Y contains a carboxyl group as a functional group that reacts with the crosslinking agent, the reactivity between the copolymer and the crosslinking agent can be adjusted. Thereby, an appropriate crosslinked structure can be produced, and there is no inconvenience in that unreacted active hydrogen is not generated.

  It is preferable that the functional group reacting with the crosslinking agent contained in X and the functional group reacting with the crosslinking agent contained in Y are the same. Thereby, the reactivity in the both terminal of a copolymer can be made uniform, and an appropriate crosslinked structure can be formed.

  The structural unit derived from the radical polymerization initiator of Y is not limited, but can be the same as the structural unit derived from the radical polymerization initiator of X.

  The structure of Y derived from the chain transfer agent is not limited, but is represented by the group consisting of the following formula (Y1), formula (Y2), formula (Y3), formula (Y4), and formula (Y5). It is preferable to include one or more structural units. Thereby, heat resistance and chemical resistance can be improved. This is because the structural units of the following formulas (Y1) to (Y5) contribute to the crosslinking, so that the steric hindrance can be more effectively mitigated, so that a stronger crosslinked structure can be formed. It is guessed.

  The structures represented by the above formulas (Y1) and (Y2) can be formed by using, for example, 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid which is a chain transfer agent. The structure represented by the formula (Y3) can be formed by using, for example, bis (4- [ethyl- (2-hydroxyethyl) carbamoyl] benzyl} trithiocarbonate, which is a chain transfer agent. The structures represented by the above formulas (Y4) and (Y5) can be formed by using, for example, 4-[(2-carboxyethylsulfanylthiocarbonyl) sulfanyl] -4-cyanopentanoic acid which is a chain transfer agent. .

  Y may include a structure derived from a chain transfer agent. This is because the structure of Y can be formed from the structure of the chain transfer agent when the copolymer represented by the general formula (1) is synthesized.

  X and Y each preferably contain a carboxyl group as a functional group that reacts with the crosslinking agent. As a result, the detailed mechanism is not clear, but the reactivity with the cross-linking agent can be made comparable at both ends of the copolymer, and a denser cross-linked structure can be formed. .

Mw (the lower limit value of the weight average molecular weight of the copolymer according to this embodiment is, for example, 2000 or more, preferably 2500 or more, and preferably 3000 or more from the viewpoint of forming an appropriate crosslinked structure. Further, from the same viewpoint as the lower limit, the upper limit of Mw of the copolymer may be, for example, 12000 or less, preferably 11000 or less, and more preferably 10,000 or less.
In addition, the upper limit of the polydispersity of the copolymer according to this embodiment is such that the physical properties of each molecular chain of the copolymer are uniform, and the shape of the resin film made of the photosensitive resin composition containing the copolymer is good. From the viewpoint of making it easy, for example, it is 2.5 or less, preferably 2.2 or less, more preferably 2.0 or less, and even more preferably 1.5 or less. From the same viewpoint as the upper limit value, the lower limit value of the polydispersity of the copolymer is preferably set to 1.0 or more, for example.
The polydispersity is represented by Mw (weight average molecular weight) / Mn (number average molecular weight), and means a dispersity indicating the width of the molecular weight distribution.

For the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn), for example, a polystyrene conversion value obtained from a calibration curve of standard polystyrene (PS) obtained by GPC measurement is used. The measurement conditions are, for example, as follows.
Tosoh gel permeation chromatography device HLC-8320GPC
Column: Tosoh TSK-GEL Supermultipore HZ-M
Detector: RI detector for liquid chromatogram Measurement temperature: 40 ° C
Solvent: THF
Sample concentration: 2.0 mg / ml

The copolymer according to this embodiment may have a peak area at a molecular weight of 1000 or less in a molecular weight distribution curve obtained by GPC (Gel Permeation Chromatography), for example, 1% or less of the whole.
Thus, by setting the ratio of the peak area at a molecular weight of 1000 or less in the molecular weight distribution curve obtained by GPC within the above range, the pattern shape of the film made of the resin composition containing the copolymer can be made favorable. it can. Therefore, it is possible to improve the operation reliability of a liquid crystal display device and a solid-state imaging device that include the film as a permanent film.
In addition, the minimum of the quantity of the low molecular weight component in a copolymer is not limited. However, the copolymer according to the present embodiment allows a case where the peak area at a molecular weight of 1000 or less is 0.01% or more of the whole in a molecular weight distribution curve obtained by GPC.
The amount of the low molecular weight component in the copolymer is calculated from the ratio of the total area of the components corresponding to the molecular weight of 1000 or less in the area of the entire molecular weight distribution based on, for example, data on the molecular weight obtained by GPC measurement. .

(Method for producing copolymer)
The copolymer according to this embodiment is produced, for example, as follows.
First, a copolymer is polymerized by a polymerization step (S1). Subsequently, a low molecular weight component is removed by a low molecular weight component removal process (S2), and the copolymer which has a copolymer as a main component is obtained.
Further, when the monomer B contains maleic anhydride, the ring opening step (S3) and the washing step (S4) are performed after the polymerization step (S1) and before the low molecular weight component removal step (S2). Also good. Part of the maleic anhydride unit in the copolymer is opened by the ring-opening step (S3). Moreover, the residual metal component derived from the metal alkoxide as the base used for the ring opening in the ring opening step (S3) or the alkali metal hydroxide as the base and the base is washed in the washing step (S4).
Details of each step will be described below.

(Polymerization step (S1))
First, the polymerization process for polymerizing the copolymer will be described.
First, a norbornene-type monomer and one or more selected from the group consisting of maleic anhydride, maleimide and maleimide derivatives are prepared. One norbornene type monomer may be prepared, or two or more types may be prepared.
In the copolymer represented by the general formula (1), A is a structural unit derived from the norbornene-type monomer. B is a structural unit derived from one or more selected from the group consisting of maleic anhydride, maleimide and maleimide derivatives.

As the monomer A, a monomer A1 represented by the following formula (2) or a monomer A2 represented by the following formula (3) can be used. Monomer A may include monomer A1 or monomer A2, or may include monomer A1 and monomer A2.
In Formula _(2), R 1 ~R ₄ may be the same as _R 1 to R ₄ in the general formula (A1) described above. Further, in the following formula (3) _may be R 5 to R ₈ are the same as _R 5 to R ₈ of general formula (A2) as described above.

（式（２）中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４およびａ_１は、上記一般式（Ａ１）と同様である。）

(In the formula (2), R ₁ , R ₂ , R ₃ , R ₄ and a ₁ are the same as those in the general formula (A1).)

Specific examples of the monomer A1 represented by the above formula (2) include norbornene, norbornadiene, bicyclo [2.2.1] -hept-2-ene (common name: 2-norbornene), and 5-methyl-2. -Norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-hexyl-2-norbornene, 5-decyl-2-norbornene, 5-allyl-2-norbornene, 5- (2-propenyl) 2-norbornene, 5- (1-methyl-4-pentenyl) -2-norbornene, 5-ethynyl-2-norbornene, 5-benzyl-2-norbornene, 5-phenethyl-2-norbornene, 2-acetyl-5 -Norbornene, methyl 5-norbornene-2-carboxylate, 5-norbornene-2,3-dicarboxylic acid anhydride and the like.
As the monomer A1 represented by the above formula (2), one or more of these can be used.

（式（３）中、Ｒ_５、Ｒ_６、Ｒ_７、Ｒ_８及びａ_２は上記一般式（Ａ２）と同様である。）

(In the formula (3), R ₅ , R ₆ , R _7, R ₈ and a ₂ are the same as those in the general formula (A2).)

  As the monomer A2 represented by the above formula (3), specifically, 5-norbornene-2-carboxylic acid, 5-norbornene-2,3-dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid monomethyl and Examples thereof include monoethyl 5-norbornene-2,3-dicarboxylate. As the monomer A2, one or more of these can be used. Especially, it is preferable to use 5-norbornene-2-carboxylic acid from a viewpoint of forming a crosslinked structure and a viewpoint of alkali solubility control.

Monomer B is one or more monomers selected from the group consisting of maleic anhydride, maleimide and a maleimide derivative represented by the following formula (4), wherein the maleimide and the maleimide derivative represented by the following formula (4) It is preferable that it is 1 type, or 2 or more types of monomers selected from the group which consists of, and it is still more preferable that it is a maleimide derivative shown by following formula (4). Heat resistance and chemical resistance can be improved by using a maleimide derivative represented by the following formula (4).
Further, in the following formula _{(4), R 12} may be the same as _{R 12} in formula (B6).

（Ｒ_１２は、炭素数１以上３０以下の有機基である。）

(R ₁₂ is an organic group having 1 to 30 carbon atoms.)

  Examples of the maleimide derivative represented by the above formula (4) include N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (4-aminophenyl) maleimide, N-benzylmaleimide, N-tert-butyl. Examples include maleimide, N-ethylmaleimide, N- (2-hydroxyethyl) maleimide, N-methoxycarbonylmaleimide, 3-maleimidopropionic acid, 4-maleimidobutyric acid and 6-maleimidohexanoic acid. Among these, it is preferable to use N-methylmaleimide. Thereby, heat resistance and chemical resistance can be improved.

Next, monomer A and monomer B are addition-polymerized to synthesize a copolymer.
In addition, as monomer A and monomer B, it does not restrict | limit using 1 type, or 2 or more types of monomers, respectively.
Although the method of addition polymerization is not limited, in the present embodiment, a copolymer is synthesized by radical polymerization using a radical polymerization initiator.
By synthesizing a copolymer having a structural unit derived from monomer A and a structural unit derived from monomer B, and having a terminal derived from a radical polymerization initiator by addition polymerization using a radical polymerization initiator. Can do.
Here, the structural unit derived from the monomer A1 is the general formula (A1). The structural unit derived from the monomer A2 is the general formula (A2).
Furthermore, by using maleic anhydride, maleimide, and a maleimide derivative represented by the above formula (4) as the monomer B, structural units of the above formula (B3), the above formula (B5), and the above general formula (B6), respectively. Can be obtained.

The molar ratio of monomer A to monomer B in the copolymer is preferably 0.5: 1 to 1: 0.5. The above 0.5: 1 to 1: 0.5 includes 0.5: 1 and 1: 0.5. Among these, the molar ratio is preferably 1: 1 from the viewpoint of improving the molecular structure controllability.
The monomer A, the monomer B, and the radical polymerization initiator are dissolved in a solvent, and then the addition polymerization is advanced by heating for a predetermined time. The heating temperature is, for example, 50 ° C. or more and 80 ° C. or less, and the heating time is 10 hours or more and 20 hours or less.
In addition, in addition polymerization, it does not restrict | limit adding additives, such as a chain transfer agent, according to the performance required for the photosensitive resin composition. It is preferable to add a chain transfer agent to control the terminal structure of the copolymer and introduce a functional group that reacts with the crosslinking agent to the terminal of the copolymer.

The radical polymerization initiator is not limited as long as it introduces a functional group that reacts with the crosslinking agent to X which is one of the copolymer ends, and an azo compound or a peroxide can be used. Among these, it is preferable to use an azo compound.
Specifically, the azo compound has a carboxyl group such as 4,4′-azobis (4-cyanovaleric acid) and 2,2′-azobis [N- (2-carboxyethyl) -2-methyl]. Radical polymerization initiator; radical polymerization initiator having an amino group such as 2,2′-azobis (2-methylpropionamidine), 2,2′-azobis [2- (2-imidazolin-2-yl) propane]; Examples thereof include radical polymerization initiators having a hydroxy group such as 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide]. Among these, it is preferable to use a radical polymerization initiator having a carboxyl group, and among these, it is more preferable to use 4,4′-azobis (4-cyanovaleric acid). Thereby, heat resistance and chemical resistance can be improved.

  The addition amount (number of moles) of the radical polymerization initiator is preferably 1% or more and 10% or less of the total number of moles of the monomer A and the monomer B. The weight average molecular weight (Mw) of the obtained copolymer can be adjusted by appropriately setting the amount of the radical polymerization initiator within the above range and appropriately setting the reaction temperature and reaction time.

Although it does not limit as a chain transfer agent, The thing containing the functional group which reacts with a crosslinking agent is preferable. Thereby, the functional group which reacts with a crosslinking agent can be introduce | transduced into Y which is one of the copolymer terminal. Therefore, the number of copolymers containing functional groups that react with the crosslinking agent at X and Y, which are both ends of the copolymer, can be increased as compared with the case where the chain transfer agent is not used. This is because, in addition to the above termination reaction, a chain transfer reaction occurs, and recombination termination, disproportionation termination, and chain transfer reaction occur in competition. Thereby, a crosslinked structure can be formed more densely and heat resistance and chemical resistance can be improved.
Specific examples of such a chain transfer agent containing a functional group that reacts with a crosslinking agent include 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid and 4-[(2-carboxyl). Chain transfer agent having a carboxyl group such as ethylsulfanylthiocarbonyl) sulfanyl] -4-cyanopentanoic acid, chain transfer having a hydroxyl group such as bis {4- [ethyl- (2-hydroxyethyl) carbamoyl] benzyl} trithiocarbonate Agents and the like. Among these, a chain transfer agent having a carboxyl group is preferable.

  The addition amount (number of moles) of the chain transfer agent is preferably 1% to 10% of the total number of moles of monomer A and monomer B. The weight average molecular weight (Mw) of the obtained copolymer can be adjusted by appropriately setting the amount of the polymerization initiator within the above range and appropriately setting the reaction temperature and the reaction time.

  As a solvent, 1 type (s) or 2 or more types can be used among diethyl ether, tetrahydrofuran, toluene, etc., for example.

  By this polymerization step, a copolymer having a structural unit derived from monomer A and a structural unit derived from monomer B and having a terminal derived from a radical polymerization initiator can be synthesized.

(Low molecular weight component removal step (S2))
Next, the organic layer containing the copolymer and low molecular weight components such as residual monomers and oligomers is concentrated and then dissolved again in an organic solvent such as THF. And hexane and methanol are added to this solution, and the copolymer containing a copolymer is coagulated and precipitated. Here, as a low molecular weight component, a residual monomer, an oligomer, a polymerization initiator, and the like are included. Next, filtration is performed, and the obtained coagulum is dried. Thereby, the copolymer which has the copolymer from which the low molecular weight component was removed as a main component (main product) can be obtained.
In the present embodiment, in the low molecular weight component removing step (S2), the extraction operation is preferably repeated until the content of low nuclei having a molecular weight of 1000 or less in the copolymer is 1% or less. Thereby, the amount of the low molecular weight component in the copolymer can be reduced to a sufficient level to suppress the deformation of the film pattern during curing.

  In addition, when the monomer B contains maleic anhydride, the ring-opening step (S3) and the washing step (S4) may be performed after the polymerization step (S1) and before the low molecular weight component removal step (S2). . This will be described below.

(Ring opening step (S3))
In the ring-opening step, in the obtained copolymer, the remaining repeating units are opened while a part of the repeating units derived from maleic anhydride is closed. Thereby, the quantity of the carboxyl group in a copolymer can be adjusted. That is, the acid value of the produced copolymer can be controlled. And the alkali solubility of the photosensitive resin composition can be adjusted by controlling the acid value.
In this embodiment, among the repeating units derived from maleic anhydride of the copolymer, for example, 50% or more of the repeating units are not opened, and the cyclic structure (anhydrous ring) of the remaining repeating units is opened. . That is, the ring opening rate of the copolymer is, for example, less than 50%. Among them, it is preferable to open 10% or more and 30% or less of the repeating units among the total number of repeating units of the cyclic structure derived from maleic anhydride of the copolymer.

Here, the ring-opening rate of the repeating unit derived from maleic anhydride can be measured as follows.
The IR absorption intensity (Abs1) of (C = O) in the acid anhydride structure of the copolymer before ring opening was measured, and the IR absorption intensity (Abs2) of (C = O) in the acid anhydride structure after ring opening. From the following formula, the ring opening rate is calculated.
Ring-opening rate (%) = (((Abs1) − (Abs2)) / (Abs1)) × 100
Acetonitrile is used as an internal standard substance.

In particular,
In the polymerization step, either (i) a metal alkoxide as a base (ii) an alcohol or an alkali metal hydroxide as a base is added to the reaction solution obtained by polymerizing the copolymer, and methyl ethyl ketone ( An organic solvent such as MEK) is further added, and the mixture is stirred at 40 ° C. or more and 50 ° C. or less for 1 hour or more and 5 hours or less to obtain a reaction solution L1. In the reaction liquid L1, a part of the anhydride ring of the repeating unit derived from the maleic anhydride of the copolymer is opened, and a part of the terminal formed by the ring opening is esterified. The remaining terminals are not esterified and have a metal salt structure.

In the present embodiment, the number of moles of metal alkoxide or alkali metal hydroxide is preferably 50% or less of the number of moles of maleic anhydride used in the polymerization step. Among them, the number of moles of metal alkoxide or alkali metal hydroxide is preferably 40% or less, 10% or more, and more preferably 30% or less of the number of moles of maleic anhydride used in the polymerization step. It is preferable. By doing in this way, the quantity of a metal alkoxide or an alkali metal hydroxide can be decreased, and the alkali metal density | concentration in the copolymer finally obtained can be reduced.
By reducing the alkali metal concentration in the copolymer, migration of metal ions can be suppressed when a device using this copolymer is formed.

As the metal alkoxide described above, one represented by M (OR ₉ ) (M is a monovalent metal and R ₉ is an organic group having 1 to 30 carbon atoms) is preferable. Examples of the metal M include alkali metals, and sodium is preferable from the viewpoint of handleability. As R < ₉ >, the thing similar to R < ₉ > in the said general formula (B1) is mentioned, for example.
Two or more different metal alkoxides may be used. However, from the viewpoint of production stability, it is preferable to use one kind of metal alkoxide.

On the other hand, as described above, the structure derived from maleic anhydride of the copolymer may be ring-opened in the presence of (ii) an alcohol and an alkali metal hydroxide as a base.
As the alkali metal hydroxide, sodium hydroxide is preferable from the viewpoint of handleability.
As the alcohol, monovalent alcohol (R ₉ OH) is preferable. As the organic group R ₉ , those described above can be used. R ₉ preferably has 1 to 30 carbon atoms.

  The repeating unit derived from maleic anhydride opened in this ring-opening step (S3) has a structure represented by the following formula (5), and has a structure having a carboxyl group salt moiety.

（Ｒ_９は炭素数１以上３０以下の有機基である。）

(R ₉ is an organic group having 1 to 30 carbon atoms.)

When the copolymer is ring-opened with (i) a metal alkoxide as a base, or (ii) an alcohol and an alkali metal hydroxide as a base, the following general formulas (B2) and The structure shown in (6) may be formed. In the following general formula (B2), R ₁₀ and R ₁₁ may be the same as R ₈ described above.

（Ｒ_１０、Ｒ_１１は、それぞれ独立して炭素数１以上３０以下の有機基である。）

(R ₁₀ and R ₁₁ are each independently an organic group having 1 to 30 carbon atoms.)

Next, an acidic aqueous solution such as hydrochloric acid or formic acid is added to the reaction liquid L1, thereby acid-treating the copolymer and replacing metal ions (Na ⁺ ) with protons (H ⁺ ).
The structural units represented by the above formulas (5) and (6) become structural units represented by the following (B1) and (B4) by proton substitution, respectively.

（上記一般式（Ｂ１）中、Ｒ_９は炭素数１以上３０以下の有機基である。）

(In the general formula (B1), R ₉ is an organic group having 1 to 30 carbon atoms.)

  In the ring-opening step (S3), it is preferable that 50% or more of the repeating units derived from maleic anhydride of the copolymer are not opened. In the copolymer, as described above, a metal such as Na is bonded to one end formed by opening an anhydrous maleic ring, but 50% or more of repeating units must not be opened. Thus, the amount of metal contained in the product copolymer can be reduced. Thereby, the quantity of the alkali metal in the copolymer finally obtained by this embodiment can be reduced, and the desired characteristic can be exhibited in the photosensitive resin composition using this copolymer. .

(Washing process (S4))
When the ring-opening step (S3) is performed, the solution containing the copolymer after ring-opening obtained in the step is washed with a mixture of water and an organic solvent (for example, methyl ethyl ketone) to remove residual metal components. Remove. The copolymer, residual monomer and oligomer after the ring opening move to the organic layer. Thereafter, the aqueous layer is removed (first cleaning).
Thereafter, again, a mixture of water and an organic solvent (for example, methyl ethyl ketone) is added to the organic layer for washing (second washing).
In the present embodiment, the above-described cleaning process is repeated, for example, 5 times or more, more preferably 10 times. Further, it is preferable to remove 85% or more of the remaining sodium and more preferably 90% or more by one washing step by adjusting the addition amount of water and organic solvent used in the washing step. Thereby, the density | concentration of the alkali metal in the copolymer after ring-opening can fully be reduced. Further, when removing residual sodium with higher efficiency than this, an unnecessarily large amount of water and an organic solvent are used, and the copolymer yield may be lowered, which is not preferable.
In addition, it is preferable to repeat a washing | cleaning process (S4) so that the alkali metal density | concentration in the copolymer after ring-opening may be 10 ppm or less, Preferably it is 5 ppm or less.

(Photosensitive resin composition)
In this embodiment, the photosensitive resin composition can contain the said copolymer, a crosslinking agent, and a photosensitive agent. In this embodiment, for example, the cross-linked structure can be controlled by appropriately selecting the type and amount of each component contained in the photosensitive resin composition and the method for preparing the photosensitive resin composition. .
Details of the crosslinking agent and the photosensitive agent will be described below.

(Crosslinking agent)
In this embodiment, a crosslinking agent will not be limited if it is a compound containing the functional group which reacts with the active hydrogen of a copolymer.
The functional group that reacts with the active hydrogen of the copolymer preferably includes, for example, one or more selected from the group consisting of a glycidyl group, an oxetanyl group, and a blocked isocyanate group, and includes a glycidyl group or an oxetanyl group. Are more preferable, and it is more preferable that a glycidyl group is included. Thereby, a suitable crosslinked structure can be formed.
Moreover, the photosensitive resin composition can also use together 1 type, or 2 or more types selected from the compound which has a block isocyanate group, an epoxy compound, and an oxetane compound.

Examples of the compound having a glycidyl group used as a crosslinking agent include allyl glycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerol polyglycidyl ether, sorbitol polyglycidyl ether, and bisphenol A. (Or F) glycidyl ether such as glycidyl ether, adipic acid diglycidyl ester, glycidyl ester such as o-phthalic acid diglycidyl ester, 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexane) carboxylate, 3, 4-epoxy-6-methylcyclohexylmethyl (3,4-epoxy-6-methylcyclohexane) carboxylate, bis (3,4-epoxy Ci-6-methylcyclohexylmethyl) adipate, dicyclopentanediene oxide, bis (2,3-epoxycyclopentyl) ether, Daicel's Celoxide 2021, Celoxide 2081, Celoxide 2083, Celoxide 2085, Celoxide 8000, Epoxide GT401, etc. And 2,2 ′-(((((1- (4- (2- (4- (oxiran-2-ylmethoxy) phenyl) propan-2-yl) phenyl) ethane-1,1- Diyl) bis (4,1-phenylene)) bis (oxy)) bis (methylene)) bis (oxirane) (eg Techmore VG3101L (printintech)), Epolite 100MF (manufactured by Kyoeisha Chemical Industries), Epiol TMP (Manufactured by NOF Corporation), 1,4-si Aliphatic glycidyl ethers such as chlorohexane dimethanol diglycidyl ether (manufactured by Shin Nippon Rika Co., Ltd., Showa Denko KK, etc.), 3,3 ′, 5,5′-tetramethyl-4,4′-bis (glycidyloxy) Aromatic glycidyl ether such as 1,1′-biphenyl, 1,1,3,3,5,5-hexamethyl-1,5-bis (3- (oxiran-2-ylmethoxy) propyl) tri-siloxane An epoxy resin such as (for example, DMS-E09 (manufactured by Gerest)) can be used.
Further, bisphenol A type such as LX-01 (manufactured by Daiso), jER1001, 1002, 1003, 1004, 1007, 1009, 1010, 828, jER825 (trade name; manufactured by Mitsubishi Chemical Corporation) Epoxy resin, bisphenol F type epoxy resin such as jER807 (trade name; manufactured by Mitsubishi Chemical), jER152, 154 (trade name; manufactured by Mitsubishi Chemical), EPPN201, 202 (trade name; manufactured by Nippon Kayaku) Phenol novolac type epoxy resin, EOCN102, 103S, 104S, 1020, 1025, 1027 (trade name; manufactured by Nippon Kayaku Co., Ltd.), jER157S70 (trade name; manufactured by Mitsubishi Chemical Corporation), and other cresol novolac type epoxy resins, araldite CY179, 184 (trade name; Huntsman Advance Material Co., Ltd., ERL-4206, 4221, 4234, 4299 (trade name; manufactured by Dow Chemical Co., Ltd.), Epicron 200, 400 (trade name; manufactured by DIC), jER871, 872 (trade name; manufactured by Mitsubishi Chemical Corporation) ), And other polyfunctional alicyclic rings such as Poly [(2-oxylanyl) -1,2-cyclohexanediol] 2-ethyl-2- (hydroxymethyl) -1,3-propanediol ether (3: 1). An epoxy resin, EHPE-3150 (manufactured by Daicel Corporation) can also be used.
The photosensitive resin composition can contain one or more of the epoxy compounds exemplified above.

Examples of the compound having an oxetanyl group used as a crosslinking agent include 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, bis [1-ethyl (3-oxetanyl)] methyl ether. 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, 4,4′-bis (3-ethyl-3-oxetanylmethoxy) biphenyl, ethylene glycol bis (3-ethyl-3- Oxetanylmethyl) ether, diethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, bis (3-ethyl-3-oxetanylmethyl) diphenoate, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol Tetrakis (3-ethyl-3-oxy) Tanylmethyl) ether, poly [[3-[(3-ethyl-3-oxetanyl) methoxy] propyl] silasesquioxane] derivatives, oxetanyl silicate, phenol novolac oxetane, 1,3-bis [(3-ethyloxetane-3 Oxetane compounds such as -yl) methoxy] benzene.
The photosensitive resin composition can contain one or more oxetane compounds exemplified above.

  Although it does not limit as a compound which has the blocked isocyanate group used as a crosslinking agent, For example, it is the compound which protected the isocyanate group of polyfunctional isocyanate with the blocking agent.

  The polyfunctional isocyanate is an organic compound having a plurality of isocyanate groups in one molecule. Examples of the polyfunctional isocyanate include 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4- Trimethyl-1,6-hexamethylene diisocyanate, lysine diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), 1 , 3-bis (isocyanatomethyl) -cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene Diisocyanate compounds such as isocyanate, tolidine diisocyanate and xylylene diisocyanate; isocyanurate-modified poly Ability isocyanate - DOO, biuret modified multifunctional isocyanates - DOO, urethane-modified polyfunctional isocyanate - one or more kinds selected from derivatives of the above diisocyanate compounds such bets, and the like.

Examples of the blocking agent include alcohol compounds, phenol compounds, active methylene compounds, mercaptan compounds, acid amide compounds, acid imide compounds, imidazole compounds, urea compounds, and oximes. 1 type or 2 types or more selected from a system compound, an amine compound, an imine compound, a bisulfite, a pyridine compound, etc. are mentioned.
Specific examples of the blocking agent include methanol, ethanol, propanol, butanol, 2-ethylhexanol, methyl cellosolve, butyl cellosolve, methylcarpitol, benzyl alcohol, cyclohexanol and the like. Alcohol compounds; phenol compounds such as phenol, cresol, ethyl phenol, butyl phenol, nonyl phenol, dinonyl phenol, styrenated phenol, hydroxybenzoic acid ester; malonic acid Active methylene compounds such as dimethyl, diethyl malonate, methyl acetoacetate, ethyl acetoacetate and acetylacetone; mercaptan compounds such as butyl mercaptan and dodecyl mercaptan; acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam Acid amide etc. Compounds; Acid imide compounds such as succinimide and maleic imide; Imidazole compounds such as imidazole and 2-methylimidazole; Urea compounds such as urea, thiourea and ethyleneurea; Formaldoxime Oxime compounds such as acetoaldoxime, acetooxime, methyl ethyl ketoxime and cyclohexanone oxime; amine compounds such as diphenylamine, aniline and carbazole; imine compounds such as ethyleneimine and polyethyleneimine; bisulfite such as sodium bisulfite Salts: Pyridine compounds such as 2-hydroxypyridine and 2-hydroxyquinoline.

  Specific examples of such a compound having a blocked isocyanate group used as a crosslinking agent include Vernock D-500 (tolylene diisocyanate blocked), Vernock D-550 (Dainippon Ink Chemical Co., Ltd.) 1,6-hexamethylene diisocyanate blocked), Vernock D-980K (1,6-hexamethylene diisocyanate blocked); Takenate B-830 (tolylene diisocyanate manufactured by Takeshi Mitsui Chemicals) -T block), Takenate B-815N (4,4′-methylenebis (cyclohexyl isocyanate) blocked), Takenate B-842N (1,3-bis (isocyanatemethyl) cyclohexane blocked), Takenate B-846N (1,3-bis (isocyanatomethyl) cyclo Hexane blocked form), Takenate B-874N (isophorone diisocyanate blocked form), Takenate B-882N (1,6-hexamethylene diisocyanate blocked form), Takenate B-890 (xylylene diisocyanate) -Takeblocked product); Takenate B-820NP (1,3-bis (isocyanatemethyl) cyclohexane blocked product), Takenate B-885N (1,6-hexamethylene diisocyanate blocked product); manufactured by Asahi Kasei Corporation Examples include Duranate MF-B60X (1,6-hexamethylene diisocyanate blocked), Duranate MF-K60X (1,6-hexamethylene diisocyanate blocked), and the like. The photosensitive resin composition which concerns on this embodiment can contain 1 type (s) or 2 or more types among these.

(Photosensitive agent)
When the photosensitive resin composition is a positive type, a photoactive compound can be used as the photosensitive agent, for example, a diazoquinone compound can be used.
For example, any one or more of the following compounds can be used.

（ｎ２は、１以上、５以下の整数である。）

(N2 is an integer of 1 or more and 5 or less.)

In each of the above compounds, Q is any one of the structures shown below or a hydrogen atom. However, at least one of Q of each compound is any of the following.
Of these, an o-naphthoquinone diazide sulfonic acid derivative in which Q is (a) or (b) is preferred from the viewpoint of transparency and dielectric constant of the photosensitive resin composition.

In addition to the photoactive compound described above, the positive photosensitive resin composition may contain an acid generator that generates an acid by light or heat. By including such an acid generator, the crosslinking reaction of the crosslinking agent can be promoted by irradiating or heating the photosensitive resin composition after exposure and development.
In this case, the acid generator is preferably 3 parts by mass or less with respect to 100 parts by mass of the crosslinking agent.
As the photoacid generator that generates an acid by light, those described later can be used.
As thermal acid generators that generate acid by heat, aromatic sulfonium salts such as SI-45L, SI-60L, SI-80L, SI-100L, SI-110L, SI-150L (manufactured by Sanshin Chemical Industry Co., Ltd.) Can be used.
For example, when the total solid content of the photosensitive resin composition is 100% by mass, the content of the thermal acid generator is preferably 0.1% by mass or more and 5% by mass or less.
In the present embodiment, the total solid content of the photosensitive resin composition indicates a component excluding the solvent.

  Further, when the photosensitive resin composition is a negative type, a photoacid generator can be used as the photosensitive agent. Any photoacid generator may be used as long as it can generate Bronsted acid or Lewis acid by absorbing light energy. Examples thereof include triphenylsulfonium trifluoromethanesulfonate, tris (4-t-butylphenyl) sulfonium-trifluoro. Sulfonium salts such as lomethanesulfonate; diazonium salts such as p-nitrophenyldiazonium hexafluorophosphate; ammonium salts; phosphonium salts; iodonium salts such as diphenyliodonium trifluoromethanesulfonate, (triccumyl) iodonium-tetrakis (pentafluorophenyl) borate; quinonediazide , Diazomethanes such as bis (phenylsulfonyl) diazomethane; 1-phenyl-1- (4-methylphenyl) sulfonyloxy Sulfonic acid esters such as -1-benzoylmethane and N-hydroxynaphthalimide-trifluoromethanesulfonate; disulfones such as diphenyldisulfone; tris (2,4,6-trichloromethyl) -s-triazine, 2- (3 And compounds such as triazines such as 4-methylenedioxyphenyl) -4,6-bis (trichloromethyl) -s-triazine. These photoacid generators can be used alone or in combination.

Moreover, when the photosensitive resin composition is a negative type, it may contain what crosslinks a copolymer by the effect | action of an acid as a 2nd crosslinking agent. The second cross-linking agent cross-links the copolymer using an acid generated from the photo-acid generator as a catalyst, and is different from the compound used for the cross-linking agent.
For example, a melamine type crosslinking agent, a urea type crosslinking agent, etc. are mentioned.
Examples of the melamine-based cross-linking agent include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxybutyl melamine, and the like, among which hexamethoxymethyl melamine is preferable.
Examples of the urea-based crosslinking agent include methylated urea resin, bismethoxymethylurea, bisethoxymethylurea, bispropoxymethylurea, bisbutoxymethylurea and the like, and methylated urea resin is particularly preferable.
Examples of commercially available methylated urea resins include MX-270, MX-280, MX-290 (manufactured by Sanwa Chemical Co., Ltd.), and the like.

  The ratio of the second crosslinking agent in the negative photosensitive resin composition is preferably 5% by mass or more and 40% by mass or less when the total solid content of the resin composition is 100% by mass. From a viewpoint, More preferably, it is 5 to 30 mass%, More preferably, it is 10 to 25 mass%.

In the above photosensitive resin composition, when the photosensitive resin composition is a positive type, the ratio of each component is as follows, for example.
When the total solid content of the photosensitive resin composition is 100% by mass, the above-mentioned copolymer is preferably contained, for example, in an amount of 30% by mass to 70% by mass, especially 40% by mass to 60% by mass. It is preferable to contain below.
Further, when the total solid content of the photosensitive resin composition is 100% by mass, it is preferable to contain the crosslinking agent, for example, 15% by mass to 50% by mass, and in particular, 20% by mass to 50% by mass. It is preferable to do.
Furthermore, when the total solid content of the photosensitive resin composition is 100% by mass, it is preferable to contain, for example, 5% by mass or more and 40% by mass or less of a photoactive compound that is a photosensitive agent. More preferably, it is contained by mass% or less.

Moreover, when the photosensitive resin composition is a negative type, the ratio of each component is as follows, for example.
When the total solid content of the photosensitive resin composition is 100% by mass, the copolymer described above is preferably contained, for example, in an amount of 30% by mass to 70% by mass, and in particular, 40% by mass to 60% by mass. It is preferable to contain.
Further, when the total solid content of the photosensitive resin composition is 100% by mass, it is preferable to contain a crosslinking agent (excluding the second crosslinking agent), for example, 15% by mass or more and 50% by mass or less. It is preferable to contain 20 mass% or more and 50 mass% or less.
Furthermore, when the total solid content of the photosensitive resin composition is 100% by mass, the amount of the photoacid generator is, for example, 0.1% by mass or more and 40% by mass or less to form a high-resolution pattern film. From the point which can do, More preferably, it is 1 to 30 mass%.

Further, additives such as a solvent, an antioxidant, a surfactant, an adhesion assistant, a dissolution accelerator, a filler, a sensitizer, and polyphenols may be added to the photosensitive resin composition.
Details of the representative components will be described below.

(solvent)
The photosensitive resin composition described in the present embodiment can be used as a varnish by dissolving the above-described components in a solvent.
Examples of such solvents include N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol Monomethyl ether, propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, butyl lactate, methyl-1,3-butylene glycol acetate, 1,3-butylene glycol-3-monomethyl ether, methyl pyruvate, and ethyl and methyl pyruvate Examples include -3-methoxypropionate.

(Antioxidant)
By adding an antioxidant, oxidation during curing of the photosensitive resin composition and oxidation of the film in the subsequent process can be suppressed.
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 glycol bis [(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 4,4'-thiobis (6-tert-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-tert-butylphenol), bis [3,3-bis (4-hydroxy-3-tert-butyl) Phenyl) butyric acid] glycol ester, 4,4′-butylidenebis (6-t-butyl-m-cresol), 2,2′-ethylidenebis (4,6-di-t-butylphenol), 2,2′-ethylidene Bis (4-s-butyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, bis [2-tert-butyl-4- Methyl-6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanate Nurate, 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-tert-butyl-5-methylbenzyl) 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- -Butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (6- (1-methylcyclohexyl) -4-methylphenol), 4,4'-butylidenebis (3-Methyl-6-tert-butylphenol), 3,9-bis (2- (3-tert-butyl-4-hydroxy-5-methylphenylpropionyloxy) -1,1-dimethylethyl) -2,4 , 8,10-tetraoxaspiro [5,5] undecane, 4,4′-thiobis (3-methyl-6-tert-butylphenol), 4,4′-bis (3,5-di-tert-butyl- 4-hydroxybenzyl) sulfide, 4,4′-thiobis (6-tert-butyl-2-methylphenol), 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amyl-hydro Non, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4-dimethyl-6- (1-methylcyclohexyl) styreneated Phenolic antioxidants such as phenol and 2,4-bis ((octylthio) methyl) -5-methylphenol; 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′-biphenylenediphosphonite, 3,5-di-t -Butyl-4-hydroxybenzylphosphonate-diethyl ester, bis- (2,6-dicumylphenyl) pentaerythritol diphosphite 2,2-methylenebis (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, bis (2,6-di-t-butyl-4-octadecyloxycarbonylethylphenyl) Phosphorous antioxidants such as pentaerythritol diphosphite; dilauryl-3,3′-thiodipropionate, bis (2-methyl-4- (3-n-dodecyl) thiopropionyloxy) -5-t-butyl Phenyl) sulfide, distearyl-3,3′-thiodipropionate, pentaerythritol -Thioether type | system | group antioxidants, such as tetrakis (3-lauryl) thiopropionate, are mentioned.
Among these, it is preferable to use hindered phenolic antioxidants which are phenolic antioxidants; phosphites and phosphates which are phosphorus antioxidants.

(Surfactant)
As the surfactant, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, and other polyoxyethylene alkyl ethers. Nonionic surfactants such as oxyethylene aryl ethers, polyoxyethylene dilaurate, polyoxyethylene dialkyl esters such as polyoxyethylene distearate, F-top EF301, F-top EF303, F-top EF352 (manufactured by Shin-Akita Kasei Co., Ltd.) ), Megafuck F171, Megafuck F172, Megafuck F173, Megafuck F177, Megafuck F444, Megafuck F470, Megafu Muck F471, MegaFuck F475, MegaFuck F482, MegaFuck F477 (manufactured by DIC), Florard FC-430, Florard FC-431, Novec FC4430, Novec FC4432 (manufactured by Sumitomo 3M), 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.) Fluorosurfactants commercially available under the names such as organosiloxane copolymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), (meth) acrylic acid copolymer polyflow No. 57, 95 (manufactured by Kyoeisha Chemical Co., Ltd.). Of these surfactants, fluorine-based surfactants are preferable.
Among these, a fluorosurfactant having a perfluoroalkyl group is effective. Specifically, Mega Fuck F171, Mega Fuck F 173, Mega Fuck F 444, Mega Fuck F 470, Mega Fuck F 471, Mega Fuck F 475, Mega Fuck F 482, Mega Fuck F 477 (manufactured by DIC), Surflon S-381, Surflon S- 383, Surflon S-393 (manufactured by AGC Seimi Chemical Co., Ltd.), Novec FC 4430, Novec FC 4432 (manufactured by Sumitomo 3M), and the like.

(Adhesion aid)
The adhesion assistant is a component that improves the adhesion of the photosensitive resin film obtained by using the photosensitive resin composition and the cured film thereof to other members.
Examples of such adhesion assistants include, but are not limited to, various silane compounds such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, vinyl silane, and methacryl silane; organic silicon having one carboxyl group in the molecule Compound; Organic silicon compound having a plurality of carboxyl groups in the molecule. Thereby, it becomes possible to further improve the adhesiveness at the time of development and after curing of the photosensitive resin composition. For this reason, it is also possible to realize a more stable electronic device manufacturing.

(Dissolution promoter)
The dissolution accelerator is a component capable of improving the solubility of the exposed portion of the resin film obtained by curing the photosensitive resin composition in the developer and improving the scum during patterning.
Examples of such a dissolution accelerator include, but are not limited to, a compound having a phenolic hydroxyl group, an alkylol compound, a methylol compound, or an acrylate compound. Among these, bifunctional or higher alkylol compounds, methylol compounds, and acrylate compounds that can improve the mechanical properties of the permanent film by crosslinking in the permanent film are preferred.

(Filler)
Although it does not limit as a filler, For example, an organic filler or an inorganic filler can be used.
Specific examples of the organic filler include organic fillers formed of epoxy resin, melamine resin, urea resin, acrylic resin, phenol resin, polyimide resin, polyamide resin, polyester resin, or fluorine resin.
Specific inorganic fillers include, for example, metal oxide fine particles such as alumina, silica, magnesia, ferrite, aluminum oxide and zirconium oxide; silicates such as talc, mica, kaolin and zeolite; barium sulfate, calcium carbonate and fullerene. And the like. The photosensitive resin composition can contain 1 type (s) or 2 or more types from these.

(Sensitizer)
The sensitizer increases the sensitivity of the photoacid generator to light and is suitable for reducing the time and energy required for activation (reaction or decomposition) of the photoacid generator and for activating the photoacid generator. It has a function of changing the wavelength of actinic radiation to the wavelength.
Such a sensitizer is not limited and can be appropriately selected depending on the sensitivity of the photoacid generator and the peak wavelength of absorption of the sensitizer. Specific examples of the sensitizer include anthracene such as 9,10-dibutoxyanthracene (CAS No. 76275-14-4), xanthones, anthraquinones, phenanthrenes, chrysene, benzpyrenes, and fluoracenes. (Fluoranthenes), rubrenes, pyrenes, indanthrines, thioxanthen-9-ones and the like, and any one or more of them can be used.

(Polyphenols)
Examples of polyphenols include phenol novolak, o-cresol novolak, p-cresol novolak, pt-butylphenol novolak, hydroxynaphthalene novolak, bisphenol A novolak, bisphenol F novolak, terpene modified novolak, dicyclopentadiene modified novolak, para Examples include xylene-modified novolak and polybutadiene-modified phenol, and any one or more of them can be used.

The following phenolic compounds can also be used.
o-cresol, m-cresol, p-cresol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, bisphenol A, B, C, E, F and G, 4,4 ', 4 " -Methylidinetrisphenol, 2,6-bis [(2-hydroxy-5-methylphenyl) methyl] -4-methylphenol, 4,4 '-[1- [4- [1- (4-hydroxyphenyl)] -1 -methylethyl] phenyl] ethylidene] bisphenol, 4,4 '-[1- [4- [2- (4-hydroxyphenyl) -2-propyl] phenyl] ethylidene] bisphenol, 4,4', 4 " Ethylidinetrisphenol, 4- [bis (4-hydroxyphenyl) methyl] -2-ethoxyphenol, 4,4 ′-[(2-hydroxyphenyl) methylene] bis [2,3 -Dimethylphenol], 4,4 '-[(3-hydroxyphenyl) methylene] bis [2,6-dimethylphenol], 4,4'-[(4-hydroxyphenyl) methylene] bis [2,6-dimethyl Phenol], 2,2 ′-[(2-hydroxyphenyl) methylene] bis [3,5-dimethylphenol], 2,2 ′-[(4-hydroxyphenyl) methylene] bis [3,5-dimethylphenol] 4,4 ′-[(3,4-dihydroxyphenyl) methylene] bis [2,3,6-trimethylphenol], 4- [bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) methyl]- 1,2-benzenediol, 4,6-bis [(3,5-dimethyl-4-hydroxyphenyl) methyl] -1,2,3-benzenetriol, 4,4 ′-[( -Hydroxyphenyl) methylene] bis [3-methylphenol], 4,4 ', 4 "-(3-methyl-1-propanyl-3-ylidine) trisphenol, 4,4', 4 '', 4 '''-(1,4-phenylenedimethylidene) tetrakisphenol, 2,4,6-tris [(3,5-dimethyl-4-hydroxyphenyl) methyl] -1,3-benzenediol, 2,4,6- Tris [(3,5-dimethyl-2-hydroxyphenyl) methyl] -1,3-benzenediol, 4,4 ′-[1- [4- [1- [4-hydroxy-3,5-bis [( Hydroxy-3-methylphenyl) methyl] phenyl] -1-methylethyl] phenyl] ethylidene] bis [2,6-bis (hydroxy-3-methylphenyl) methyl] phenol and the like.
Among these compounds, 4,4 ′, 4 ″ -methylidynetrisphenol, 2,6-bis [(2-hydroxy-5-methylphenyl) methyl] -4-methylphenol, 4,4 ′-[1 -[4- [1- (4-Hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol, 4,4 ′-[1- [4- [2- (4-hydroxyphenyl) -2-propyl] Phenyl] ethylidene] bisphenol, 4,4 ′, 4 ″ -ethylidinetrisphenol and the like are preferable. Any one or more of these can be used. More preferably, it is any one or more of the following compounds.

  In the photosensitive resin composition, the content of the polyphenols is preferably 0.1% by mass or more and 30% by mass or less, for example, when the solid content excluding the solvent is 100% by mass. % Or less is preferable.

(Preparation of photosensitive resin composition)
The method for preparing the photosensitive resin composition in the present embodiment is not limited and can be prepared using a conventionally known method.
For example, it can be prepared by mixing and dissolving each of the above components in a solvent. Thereby, the photosensitive resin composition used as the varnish can be obtained.

(Use)
The resin film of this embodiment consists of the said photosensitive resin composition. Specifically, the resin film is a dry film or a cured film of the photosensitive resin composition.
The photosensitive resin composition of the present embodiment is used for forming a resin film such as a resist or a permanent film. Such an application is suitable from the viewpoint of heat resistance.
The resist is, for example, a resin film obtained by applying a photosensitive resin composition by a method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., and removing the solvent. Composed.
The permanent film is composed of a cured film obtained by exposing and developing the resin film, patterning it into a desired shape, and curing it by heat treatment or the like. This permanent film can be used as, for example, a protective film, an interlayer film, or a dam material.

  The electronic device 100 of this embodiment can be an electronic device including the resin film. Specifically, in the electronic 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. Here, the resin film is preferably formed by exposing the coating film formed of the photosensitive resin material to ultraviolet light and patterning it by developing, and then heat-curing it.

The electronic device 100 will be described below.
An electronic device 100 shown in FIG. 1 is, for example, a semiconductor chip. In this case, for example, a semiconductor package can be obtained by mounting the electronic device 100 on the wiring board via the bumps 52. The electronic device 100 includes a semiconductor substrate provided with a semiconductor element such as a transistor, and a multilayer wiring layer (not shown) provided on the semiconductor substrate. An interlayer insulating film 30 and an uppermost layer wiring 34 provided on the interlayer insulating film 30 are provided in the uppermost layer of the multilayer wiring layer. The uppermost layer wiring 34 is made of, for example, aluminum Al. Further, a passivation film 32 is provided on the interlayer insulating film 30 and the uppermost layer wiring 34. An opening through which the uppermost layer wiring 34 is exposed is provided in a part of the passivation film 32.

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

  Bumps 52 are formed in the openings provided in the insulating layer 44 via, for example, an UBM (Under Bump Metallurgy) layer 50. The electronic device 100 is connected to a wiring board or the like via bumps 52, for example.

  It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

Next, examples of the present invention will be described.
First, each material used in the examples was prepared as shown below.

(Copolymer)
Copolymers of the following synthesis examples 1 to 3 were prepared.
Hereinafter, the synthesis method of each copolymer will be described in detail.

(Synthesis Example 1)
To a suitably sized reaction vessel equipped with a stirrer and condenser, N-methylmaleimide (2.8 g, 0.025 mol), 5-norbornene-2-carboxylic acid (1.7 g, 0.012 mol), 5- Methyl norbornene-2-carboxylate (1.9 g, 0.012 mol) and 4,4′-azobis (4-cyanovaleric acid) (0.06 g, 0.0002 mol) were weighed and dissolved in methyl ethyl ketone and toluene. .
The dissolved solution was purged with nitrogen for 10 minutes to remove oxygen, and then heated at 60 ° C. for 16 hours with stirring. Thereafter, methyl ethyl ketone was further added to the solution.
Subsequently, methanol and hexane were added and the organic layer was separated to remove unreacted monomers.
Further, propylene glycol monomethyl ether acetate (PGMEA) was added, and methyl ethyl ketone, methanol and hexane in the system were distilled off under reduced pressure.
From the above, 20 g of a 20% by mass copolymer solution of Synthesis Example 1 containing each of the copolymers represented by the following formulas (7-1) and (7-2) was obtained (Mw measured by GPC = 8500). , Mw / Mn = 1.8).

(Synthesis Example 2)
To a suitably sized reaction vessel equipped with a stirrer and condenser, N-methylmaleimide (2.8 g, 0.025 mol), 5-norbornene-2-carboxylic acid (1.7 g, 0.012 mol), 5- Methyl norbornene-2-carboxylate (1.9 g, 0.012 mol) and 4,4′-azobis (4-cyanovaleric acid) (0.07 g, 0.0002 mol), 2-{[(2-carboxyethyl) [Sulfanylthiocarbonyl] sulfanyl} propanoic acid (0.006 g, 0.0002 mol) was weighed and dissolved in methyl ethyl ketone and toluene.
The dissolved solution was purged with nitrogen for 10 minutes to remove oxygen, and then heated at 60 ° C. for 16 hours with stirring. Thereafter, methyl ethyl ketone was further added to the solution.
Subsequently, methanol and hexane were added and the organic layer was separated to remove unreacted monomers.
Further, propylene glycol monomethyl ether acetate (PGMEA) was added, and methyl ethyl ketone, methanol and hexane in the system were distilled off under reduced pressure. This obtained 20 g of 20 mass% copolymer solutions of the synthesis example 2 (Mw = 5500 measured by GPC, Mw / Mn = 1.5).

The obtained copolymer of Synthesis Example 2 (0.03 g) was distilled off under reduced pressure, then dissolved in dimethyl sulfoxide (0.5 g), and ¹ H-NMR measurement was performed with a nuclear magnetic resonance apparatus manufactured by JEOL. . Thereby, the peak of the terminal carboxyl group derived from 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid was confirmed at around 12.5 ppm. This confirmed that a copolymer having a carboxyl group at the end of the copolymer was synthesized in Synthesis Example 2.
Also, compared with Mw = 8500 in Synthesis Example 1, Mw = 5500 in Synthesis Example 2. This confirmed that radical transfer from the growth copolymer to the chain transfer agent occurred in the process of synthesizing the copolymer.
As mentioned above, the copolymer of the synthesis example 2 is each copolymer of the structure shown by the following Formula (8-1), Formula (8-2), Formula (8-3), and Formula (8-4). Including.

(Synthesis Example 3)
To a suitably sized reaction vessel equipped with a stirrer and condenser, N-methylmaleimide (2.8 g, 0.025 mol), 5-norbornene-2-carboxylic acid (1.7 g, 0.012 mol), 5- Weigh methyl norbornene-2-carboxylate (1.9 g, 0.012 mol) and 2,2′-azobis (2-methylpropionic acid) dimethyl (0.06 g, 0.0002 mol) and dissolve in methyl ethyl ketone and toluene I let you.
The dissolved solution was purged with nitrogen for 10 minutes to remove oxygen, and then heated at 60 ° C. for 16 hours with stirring. Thereafter, methyl ethyl ketone was further added to the solution.
Subsequently, methanol and hexane were added and the organic layer was separated to remove unreacted monomers.
Further, propylene glycol monomethyl ether acetate (PGMEA) was added, and methyl ethyl ketone, methanol and hexane in the system were distilled off under reduced pressure. This obtained 20 g of 20 mass% copolymer solutions of the synthesis example 3 containing each copolymer shown by following formula (9-1) and Formula (9-2) (Mw = measured by GPC = 10,000, Mw / Mn = 1.5).

架橋剤２：下記式（１１）で表される、架橋剤（プリンテック社製、ＶＧ３１０１Ｌ）を使用した。

(Crosslinking agent)
Crosslinking agent 1: A crosslinking agent (LX-01, manufactured by Daiso Corporation) represented by the following formula (10) was used.

Crosslinking agent 2: A crosslinking agent (VG3101L, manufactured by Printec Co., Ltd.) represented by the following formula (11) was used.

(Surfactant)
A surfactant having a perfluoroalkyl group (Megafac F477, manufactured by DIC Corporation) was used as surfactant 1.

(Photosensitive agent)
Esterified product of 4,4 ′-(1- {4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl} ethylidene) bisphenol and 1,2-naphthoquinonediazide-5-sulfonyl chloride (Daitokemix Co., Ltd.) Manufactured by PA-28) was used as photosensitive agent 1.

(Preparation of photosensitive resin compositions of Examples and Comparative Examples)
For each example and each comparative example, the 20% PGMEA solution of the copolymer prepared in Synthesis Examples 1 to 3, the crosslinking agent, the surfactant, and the photosensitizer were added in an appropriate amount of propylene glycol 1 in the blending amounts shown in Table 1. -It was dissolved in monomethyl ether 2-acetate (PGMEA) and stirred. After stirring, the mixture was filtered with a 0.2 μm filter to prepare a varnish-like photosensitive resin composition.
Here, when preparing the photosensitive resin composition of each Example and each comparative example, PGMEA was prepared so that content of a copolymer component might be 30%.
In addition, all the compounding compositions described in Table 1 are described in parts by mass.

(sensitivity)
The photosensitive resin composition of Example 3 was spin-coated on a 4-inch silicon wafer treated with HMDS (Hexamethyldisilazane) and baked on a hot plate at 90 ° C. for 120 seconds to obtain a thin film having a thickness of about 8.0 μm. The thin film was exposed with a g + h + i line mask aligner (PLA-501F) manufactured by Canon Inc. using a mask having a 10 μm line and a space width of 1: 1. Next, the resist pattern formed by baking on a hot plate at 110 ° C. for 120 seconds and developing with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds has a line width of 10 μm: space width = The exposure amount (mJ / cm ² ) when 1: 1 was used as sensitivity.
Thereby, Example 3 confirmed that it was a photosensitive resin composition provided with appropriate sensitivity.

(Alkali soluble)
The photosensitive resin composition of each Example and each comparative example was apply | coated on the silicon wafer, and the thin film about 5.0 micrometers thick was obtained by drying on 80 degreeC and 90 second conditions. This thin film was immersed in a 2.38% TMAH developer for 3 minutes and then washed with pure water. The thin film after washing was visually observed, and a film having no residue was marked with ◯, and a film having residues was marked with x.
Thereby, each Example confirmed that it was a photosensitive resin composition provided with appropriate alkali solubility.

(Production of resin film)
About each of each Example and each comparative example, the resin film was produced as follows using the obtained photosensitive resin composition. First, the varnish-like photosensitive resin composition was applied to a 6-inch wafer, and then the solvent was removed by heat treatment at 80 ° C. for 90 seconds. Next, the photosensitive resin composition was heat-treated in an oven to cure the photosensitive resin composition. In each example and each comparative example, the inside of the oven on which the wafer was placed was replaced with nitrogen at 30 ° C. for 30 minutes, and the temperature was increased to 160 ° C. at a temperature increase rate of 5 ° C./min. The above heat treatment was performed by holding for 90 minutes. After the heat treatment, the temperature in the oven was lowered to 70 ° C. or less at a temperature drop rate of 5 ° C./min, and the wafer was taken out. Next, the cured film of the photosensitive resin composition was peeled from the wafer using hydrofluoric acid, and dried under conditions of 60 ° C. and 10 hours. Thereby, a resin film was obtained.

(chemical resistance)
About the resin film using the photosensitive resin composition of each Example and each comparative example, chemical resistance was evaluated as follows.
First, about the resin film produced by the above, the film thickness before solvent immersion was measured. Next, the resin film was immersed in N-methylpyrrolidone (manufactured by Kanto Chemical Co., Ltd.) at 60 ° C. for 10 minutes, rinsed with pure water, and then the film thickness after immersion in the solvent was measured.
From the film thickness before solvent immersion measured as described above and the film thickness after solvent immersion, the film thickness change rate was calculated using the following equation. A smaller film thickness change rate indicates higher chemical resistance.
Change rate of film thickness (%) = [{(film thickness after solvent immersion) − (film thickness before solvent immersion)} / (film thickness before solvent immersion)] × 100

(Heat-resistant)
The glass transition temperature Tg was measured about the resin film using the photosensitive resin composition of each Example and each comparative example. Measurement is performed on a test piece made of a resin film (width 5 mm × length 10 mm or more × thickness 0.005 mm or more and 0.01 mm or less) using a thermomechanical analyzer (ThermoMechanical Analysis: TMA), a starting temperature of 30 ° C., The measurement was performed under conditions of a temperature range of 30 ° C. to 400 ° C. and a temperature increase rate of 5 ° C./min.

(Mechanical properties)
In addition to the chemical resistance and the heat resistance, mechanical properties were evaluated. This is because the photosensitive resin composition that forms a dense cross-linked structure is estimated to have improved mechanical properties.
Tensile elongation and tensile strength were measured as follows for the resin films using the photosensitive resin compositions of the examples and comparative examples. First, a tensile test (tensile speed: 0.05 mm / min) was performed on a test piece made of a resin film (width 10 mm × length 60 mm or more × thickness 0.005 mm or more and 0.01 mm or less), temperature 23 ° C., humidity 55 % Atmosphere. The tensile test was performed using a tensile tester (Tensilon RTC-1210A) manufactured by Orientec. Subsequently, the tensile elongation rate and the tensile strength were calculated from the results of the tensile test. Here, the tensile test was performed with the number of tests n = 5, the maximum value of 5 times was determined, and this was taken as the measured value.
As a result of evaluating the mechanical properties, it was confirmed that in Examples 2 and 3 using Synthesis Example 2 synthesized using a chain transfer agent, the tensile elongation and tensile strength were improved.

Table 1 below shows the blending amounts and evaluation results of the above-described Examples and Comparative Examples.
Note that “-” in the evaluation result section indicates that no evaluation is performed.

  As shown in Table 1, it was confirmed that the photosensitive resin composition of each example has improved heat resistance and chemical resistance as compared with the photosensitive resin composition of each comparative example.

100 Electronic Device 30 Interlayer Insulating Film 32 Passivation Film 34 Top Layer Wiring 40 Rewiring Layers 42, 44 Insulating Layer 46 Rewiring 50 UBM Layer 52 Bump

Claims (8)

A copolymer represented by the following general formula (1);
A crosslinking agent;
A photosensitizer,
A photosensitive resin composition comprising:

(In general formula (1),
l and m respectively represent the molar contents of A and B in the copolymer;
l + m = 1,
A includes one or more structural units represented by the following general formula (A1) or general formula (A2),
B includes one or more structural units represented by the following general formula (B1), general formula (B2), formula (B3), formula (B4), formula (B5), or general formula (B6),
X is an organic group having 1 to 30 carbon atoms including a functional group that reacts with the crosslinking agent,
Y is hydrogen or an organic group having 1 to 30 carbon atoms. )

(In general formula (A1), R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen or an organic group having 1 to 30 carbon atoms, except for a carboxyl group.
a ₁ is 0, 1 or 2. )

(In the general formula (A2), R ₅ , R ₆ , R ₇ and R ₈ are each independently hydrogen or an organic group having 1 to 30 carbon atoms,
R ₅ , R ₆ , R ₇ and R ₈ contain at least one carboxyl group,
a ₂ is 0, 1 or 2. )

(In General Formula (B1), R ₉ is an organic group having 1 to 30 carbon atoms.)

(In General Formula (B2), R ₁₀ and R ₁₁ are each independently an organic group having 1 to 30 carbon atoms.)

(In the general formula (B6), R ₁₂ is an organic group having 1 to 30 carbon atoms.) In the photosensitive resin composition of Claim 1,
The said crosslinking agent is a photosensitive resin composition containing 1 or more types selected from the group which consists of a glycidyl group, an oxetanyl group, and a block isocyanate group as a functional group which reacts with the said copolymer. In the photosensitive resin composition of Claim 1 or 2,
In the copolymer represented by the general formula (1), X is a carboxyl group, primary amino group, secondary amino group, hydroxyl group, imidazole group, imidazoline group, ester as the functional group that reacts with the crosslinking agent. The photosensitive resin composition containing 1 or more types selected from the group which consists of group and an amide group. In the photosensitive resin composition of any one of Claim 1 to 3,
The photosensitive resin composition in which A in the copolymer represented by the general formula (1) includes a structural unit represented by the general formula (A1) and a structural unit represented by the general formula (A2). In the photosensitive resin composition of any one of Claim 1 to 4,
In the copolymer represented by the general formula (1), Y represents a carboxyl group, a primary amino group, a secondary amino group, a hydroxyl group, an imidazole, an imidazoline, an ester group, and an amide as a functional group that reacts with a crosslinking agent. A photosensitive resin composition comprising at least one selected from the group consisting of groups. In the photosensitive resin composition of any one of Claim 1 to 5,
The photosensitive resin composition in which B in the copolymer represented by the general formula (1) includes a structural unit represented by the formula (B5) or the general formula (B6).   The resin film which consists of the photosensitive resin composition of any one of Claim 1 to 6.   An electronic device comprising the resin film according to claim 7.

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