WO2018131351A1 - Negative photosensitive resin composition, resin film and electronic device - Google Patents

Abstract

This negative photosensitive resin composition contains a polymer that is specifically a copolymer, a crosslinking agent and a sensitizing agent. According to the present invention, the copolymer contains: a norbornene-type structural unit that is substituted by a functional group containing a terminal unsaturated carbon double bond; a norbornene-type structural unit that is substituted by a carboxyl group; and a structural unit that is derived from maleic acid anhydride, a maleic acid anhydride derivative, maleimide or a maleimide derivative.

Description

Negative photosensitive resin composition, resin film and electronic device

The present invention relates to a negative photosensitive resin composition, a resin film, and an electronic device.

In the field of the negative photosensitive resin composition so far, various techniques have been developed for the purpose of increasing the accuracy of resist patterns accompanying pattern miniaturization. As this type of technology, for example, the technology described in Patent Document 1 can be cited. According to this document, a radiation-sensitive resin composition containing a [A] polymer and a [B] acid generator is described. And, because the [A] polymer has the structural unit (I) and the structural unit (II), it is excellent in LWR (Line Width Roughness) performance and defect suppression property, which indicates a small variation in line width. (Patent Document 1, paragraph 0012).
Here, the structural unit (I) is N- (t-butyloxycarbonylmethyl) maleimide, N- (1-methyl-1-cyclopentyloxycarbonylmethyl) maleimide, or N- (2-ethyl-2-adamantyloxy) It is described that it is a structural unit derived from (carbonylmethyl) maleimide. Further, it is described that the structural unit (II) is a structural unit derived from 2-norbornene.

Japanese Patent Application Laid-Open No. 2015-184458

The inventor produced a resin film made of a negative photosensitive resin composition, and examined the durability of the resin film such as heat resistance and solvent resistance, and developability such as the remaining film ratio after development. As a result, it has been found that the resin film made of the radiation-sensitive resin composition described in Patent Document 1 has room for further improvement in terms of durability and developability.
Then, this invention makes it a subject to provide the negative photosensitive resin composition which can improve durability and developability with sufficient balance, without impairing alkali developability.

In order to improve the durability such as heat resistance and solvent resistance of a resin film made of a negative photosensitive resin composition and the developability such as the remaining film ratio after development, the present inventor The structural unit with As a result, the copolymer has a norbornene-type structural unit substituted with a functional group containing a terminal carbon unsaturated double bond, a norbornene-type structural unit substituted with a carboxyl group, maleic anhydride, maleic anhydride It has been found that by including a derivative, a maleimide or a structural unit derived from a maleimide derivative, durability and developability can be improved in a balanced manner without impairing alkali developability.
As described above, the present inventors include a copolymer containing a specific structural unit, so that the durability and developability of the resin film using the negative photosensitive resin composition can be obtained without impairing alkali developability. The present invention has been completed.

According to the present invention,
A polymer which is a copolymer represented by the following formula (1);
A crosslinking agent;
A negative photosensitive resin composition containing a photosensitive agent is provided.

(In the formula (1),
l and m represent the molar content in the polymer,
l + m = 1,
A is a structural unit represented by the following formula (A1);
A structural unit represented by the following formula (A2):
B includes at least one structural unit represented by the following formula (B1), the following formula (B2), the following formula (B3), the following formula (B4), the following formula (B5), or the following formula (B6). )

(In the 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, and at least R ₁ , R ₂ , R ₃ and R ₄ Contains one terminal unsaturated carbon double bond, n is 0, 1 or 2)

(In the formula (A2), R ₅ , R ₆ and R ₇ are each independently hydrogen or an organic group having 1 to 30 carbon atoms, and n is 0, 1 or 2.)

(In formula (B1), R ₈ is independently an organic group having 1 to 30 carbon atoms.)

(In Formula (B2), R ₉ and R ₁₀ are each independently an organic group having 1 to 30 carbon atoms.)

(In Formula (B6), R ₁₁ is independently an organic group having 1 to 30 carbon atoms.)

Moreover, according to the present invention, there is provided a resin film comprising the above negative photosensitive resin composition.

Furthermore, according to the present invention, an electronic device including the resin film is provided.

According to the present invention, there is provided a negative photosensitive resin composition capable of improving the durability and developability of a resin film comprising a negative photosensitive resin composition without impairing alkali developability.

The above-described object and other objects, features, and advantages will be further clarified by a preferred embodiment described below and the following drawings attached thereto.

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, similar constituent elements are denoted by the same reference numerals, and description thereof is omitted. Further, in this embodiment, A to B mean A or more and B or less.

The outline | summary of the negative photosensitive resin composition of this embodiment is demonstrated.
The negative photosensitive resin composition of the present embodiment is
A polymer which is a copolymer represented by the following formula (1);
A crosslinking agent;
And a photosensitizer.

(In the formula (1),
l and m represent the molar content in the polymer,
l + m = 1,
A is a structural unit represented by the following formula (A1);
A structural unit represented by the following formula (A2):
B includes at least one structural unit represented by the following formula (B1), the following formula (B2), the following formula (B3), the following formula (B4), the following formula (B5), or the following formula (B6). )

(In the 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, and at least R ₁ , R ₂ , R ₃ and R ₄ Contains one terminal unsaturated carbon double bond, n is 0, 1 or 2)

(In the formula (A2), R ₅ , R ₆ and R ₇ are each independently hydrogen or an organic group having 1 to 30 carbon atoms, and n is 0, 1 or 2.)

(In formula (B1), R ₈ is independently an organic group having 1 to 30 carbon atoms.)

(In Formula (B2), R ₉ and R ₁₀ are each independently an organic group having 1 to 30 carbon atoms.)

(In Formula (B6), R ₁₁ is independently an organic group having 1 to 30 carbon atoms.)

According to this embodiment, the copolymer comprises a norbornene-type structural unit substituted with a functional group containing a terminal unsaturated carbon double bond, a norbornene-type structural unit substituted with a carboxyl group, and maleic anhydride. And structural units derived from maleic anhydride derivatives, maleimides or maleimide derivatives.

The negative photosensitive resin composition according to this embodiment is cured by the radical chain reaction caused by the photosensitizer generating radicals upon exposure. In the negative photosensitive resin composition according to the present embodiment, it is considered that the terminal unsaturated carbon double bond of the norbornene side chain of the copolymer contributes to the radical chain reaction. Thus, although the detailed mechanism is not clear, the negative photosensitive resin composition according to the present embodiment has a crosslinked structure formed by radical chain reaction as compared with the conventional negative photosensitive resin composition. It is estimated that the density can be improved and the mobility of the molecular chain can be more limited. Therefore, durability such as heat resistance and solvent resistance of a cured film of the negative photosensitive resin composition and developability such as a remaining film ratio after development can be improved.

In addition, the negative photosensitive resin composition according to the present embodiment is, for example, partially exposed and cured as described above, while the portion is not exposed and not cured. And the unexposed part which is not hardened | cured can be removed with an alkaline solution, and it can use for a desired use.
In the copolymer according to this embodiment, the norbornene-type structural unit substituted with a functional group containing a terminal unsaturated carbon double bond substitutes a part of the norbornene-type structural unit substituted with a carboxyl group. Formed by. And the norbornene-type structural unit substituted by a part of carboxyl group remains in a copolymer as it is. Thereby, the copolymer which concerns on this embodiment contains the norbornene-type structural unit provided with a carboxyl group. Thereby, when removing an unexposed part, alkali solubility can be improved.
Further, the alkali solubility of the copolymer can be appropriately controlled by including a structural unit derived from maleic anhydride, a maleic anhydride derivative, a maleimide or a maleimide derivative.
In the conventional negative photosensitive resin composition, when improving the durability and developability of the cured film of the negative photosensitive resin composition, the alkali solubility is lowered simply by making the structure easy to crosslink. There was an inconvenience that it would end up. However, the negative photosensitive resin composition according to this embodiment includes a norbornene type structural unit in which the copolymer is substituted with a functional group containing a terminal unsaturated carbon double bond, and a norbornene type substituted with a carboxyl group. By improving the durability and developability of the cured film without deteriorating alkali solubility, it is possible to include the structural unit of the above and the structural unit derived from maleic anhydride, maleic anhydride derivative, maleimide or maleimide derivative. can do.
As described above, the negative photosensitive resin composition according to this embodiment can improve the durability and developability of the resin film made of the negative photosensitive resin composition without impairing the alkali developability. .

Hereinafter, each component of the negative photosensitive resin composition of this embodiment is demonstrated.
The negative photosensitive resin composition according to the present embodiment includes a polymer, a crosslinking agent, and a photosensitive agent.

(polymer)
First, the polymer according to this embodiment will be described.
The polymer according to the present embodiment is a copolymer represented by the following formula (1). In addition, following formula (1) does not limit the arrangement | sequence of a copolymer. As the arrangement of the copolymer, for example, a random copolymer, an alternating copolymer, a block copolymer, a periodic copolymer, or the like can be selected.

(In the formula (1),
l and m represent the molar content in the polymer,
l + m = 1,
A is a structural unit represented by the following formula (A1);
A structural unit represented by the following formula (A2):
B includes at least one structural unit represented by the following formula (B1), the following formula (B2), the following formula (B3), the following formula (B4), the following formula (B5), or the following formula (B6). )

The composition ratio between the structural unit A and the structural unit B in the copolymer will be described. When the molar content (mol%) of the structural unit of A is 1 and the molar content (mol%) of the structural unit of B is m and l + m = 1, the numerical range of 1 is 0.1 ≦ l ≦ 0.9. The numerical range of m is 0.1 ≦ m ≦ 0.9. Thereby, by sufficiently including the structural unit of A and the structural unit of B, it is possible to realize improvement in heat resistance, improvement in solvent resistance, and improvement in the remaining film ratio after development.

In the copolymer represented by the above formula (1), A is a structural unit derived from a norbornene-type monomer substituted by a functional group containing a terminal unsaturated carbon double bond represented by the following formula (A1): And a structural unit derived from a norbornene-type monomer substituted with a carboxyl group represented by the following formula (A2).
As described above, when the copolymer contains a structural unit represented by the following formula (A1), the heat resistance, the solvent resistance, and the remaining film ratio after development as a negative photosensitive resin composition can be obtained. Can be improved.
Moreover, alkali solubility when it is set as a negative photosensitive resin composition can be adjusted as mentioned above because a copolymer contains the structural unit shown by following formula (A2).

(In the 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, and at least R ₁ , R ₂ , R ₃ and R ₄ Contains one terminal unsaturated carbon double bond, n is 0, 1 or 2)

(In the formula (A2), R ₅ , R ₆ and R ₇ are each independently hydrogen or an organic group having 1 to 30 carbon atoms, and n is 0, 1 or 2.)

In this embodiment, R ₁ to R ₄ in the above formula (A1) and R ₅ to R ₇ in the above formula (A2) are hydrogen or an organic group having 1 to 30 carbon atoms in the structure. May contain one or more atoms selected from O, N, S, P and Si.
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, control of the acid value in a polymer can be made easy.

In this embodiment, R ₁ to R ₄ in the above formula (A1) and R ₅ to R ₇ in the above formula (A2) are each independently hydrogen or an organic compound having 1 to 30 carbon atoms. Each of which is independently hydrogen or an organic group having 1 to 10 carbon atoms, more preferably independently hydrogen or an organic group having 1 to 5 carbon atoms. More preferred is hydrogen or an organic group having 1 to 3 carbon atoms.

In this embodiment, examples of the organic group constituting R ₁ to R ₄ in the above formula (A1) and R ₅ to R ₇ in the above formula (A2) include an alkyl group, an alkenyl group, and an alkynyl group. , Alkylidene group, aryl group, aralkyl group, alkaryl group, cycloalkyl 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 cycloalkyl group include an adamantyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of the heterocyclic group include an epoxy group and an oxetanyl group.

In the present embodiment, in the above formula (A1), R ₁ , R ₂ , R ₃ and R ₄ include at least one terminal unsaturated carbon double bond. Thereby, in a negative photosensitive resin composition, the structural unit which is radicalized at the time of exposure and contributes to a crosslinked structure can be increased. In addition, although the detailed mechanism is not clear, the side chain of the norbornene-type structural unit contributes to the crosslinked structure, so that the movement of the polymer chain can be more firmly limited. Thereby, the heat resistance of a negative photosensitive resin composition, solvent resistance, and the remaining film rate after image development can be improved with sufficient balance.
In the present embodiment, it is not particularly limited that R ₁ , R ₂ , R _3, and R ₄ include two or more terminal unsaturated carbon double bonds. Of R ₁ to R ₄ , one containing a terminal unsaturated carbon double bond is preferably any one of R ₁ to R ₄ . Thereby, the functional group containing a terminal unsaturated carbon double bond does not become a steric hindrance, and is preferable from the viewpoint that a suitable crosslinked structure can be formed.

In the above formulas (A1) and (A2), n is independently 0, 1 or 2, n is 0 or 1, and n is 0.

R ₁ , R ₂ , R ₃ and R ₄ preferably contain a structure represented by the following formula (E1) in order to contain a terminal unsaturated carbon double bond. Among the structures represented by the formula (E1), it is more preferable to include a structure represented by the following formula (E2). Thereby, a suitable crosslinked structure can be formed. Therefore, the heat resistance, solvent resistance, and remaining film ratio after development of the negative photosensitive resin composition can be improved in a balanced manner.

(In the formula (E1), R _e is independently hydrogen or an organic group having 1 to 10 carbon atoms.)

(In formula (E2), R _e is independently hydrogen or an organic group having 1 to 10 carbon atoms.)

In the above formulas (E1) and (E2), R _e is independently hydrogen or an organic group having 1 to 10 carbon atoms, preferably hydrogen or an organic group having 1 to 7 carbon atoms, It is more preferably an organic group having 1 to 5 carbon atoms, more preferably hydrogen or an organic group having 1 to 3 carbon atoms, and particularly preferably hydrogen or an organic group having 1 carbon atom.

Specific examples of R ₁ , R ₂ , R ₃ and R ₄ containing a terminal unsaturated carbon double bond include vinyl group, vinylidene group, acrylic group, methacryl group, acrylate group, methacrylate group and the like. Among these, R ₁ , R ₂ , R ₃ and R ₄ including a terminal unsaturated carbon double bond may be at least one selected from the group consisting of an acryl group, a methacryl group, an acrylate group and a methacrylate group. Preferably, it is an acrylate group or a methacrylate group.

The lower limit of the content of the structural unit represented by the above formula (A1) in the copolymer is preferably 0.1 mol or more with respect to 1 mol of the structural unit represented by the above formula (A2), More preferably, it is 0.2 mol or more. Thereby, a suitable crosslinked structure can be formed.
The upper limit of the content of the structural unit represented by the above formula (A1) in the copolymer is, for example, 3.0 mol or less with respect to 1 mol of the structural unit represented by the above formula (A2). It is preferably 2.0 mol or less, more preferably 1.0 mol or less, and even more preferably 0.7 mol or less. Thereby, alkali solubility can be expressed suitably.
In this embodiment, the content of the structural unit represented by the above formula (A1) with respect to 1 mol of the structural unit represented by the above formula (A1) in the polymer is, for example, a nuclear magnetic resonance apparatus (for example, JEOL Ltd.). Can be evaluated by 1H-NMR measurement.

In the copolymer represented by the above formula (1), B represents the following formula (B1), the following formula (B2), the following formula (B3), the following formula (B4), the following formula (B5), or the following formula. Including at least one of the structural units represented by (B6).
Among these, it is preferable to include a structural unit represented by the following formula (B5) or the following formula (B6). Thereby, alkali solubility can be improved and developability can be improved.
Furthermore, it is more preferable that the following formula (B6) is included in the following formula (B5) or the following formula (B6). Thereby, alkali solubility when it is set as a negative photosensitive resin composition can be adjusted, and also heat resistance can be improved.

(In formula (B1), R ₈ is independently an organic group having 1 to 30 carbon atoms.)

(In Formula (B2), R ₉ and R ₁₀ are each independently an organic group having 1 to 30 carbon atoms.)

(In Formula (B6), R ₁₁ is independently an organic group having 1 to 30 carbon atoms.)

In this embodiment, B preferably further includes a structural unit represented by the above formula (B5) in addition to the structural unit represented by the above formula (B6). By including both the structural units represented by the above formula (B6) and the above formula (B5), when the negative photosensitive resin composition is obtained, the alkali solubility can be improved and the sensitivity can be further improved. Thereby, when it is set as a negative photosensitive resin composition, in addition to the improvement of heat resistance, solvent resistance, and the remaining film rate after image development, it can maintain maintaining the outstanding sensitivity.

In the present embodiment, the organic group having 1 to 30 carbon atoms constituting R ₈ to R ₁₁ in the above formulas (B1), (B2), and (B6) has O, N, S, One or more atoms selected from P and Si may be included.
Further, in the present embodiment, any of organic groups constituting R ₈ to R ₁₁ may not have an acidic functional group. Thereby, control of the acid value in a polymer can be made easy.

In this embodiment, R ₈ to R ₁₁ in the above formulas (B1), (B2), and (B6) are each independently an organic group having 1 to 30 carbon atoms, and each independently It is preferably an organic group having 1 to 10 carbon atoms, more preferably independently an organic group having 1 to 5 carbon atoms, and each independently an organic group having 1 to 3 carbon atoms. Is more preferable.

In the present embodiment, the organic groups constituting R ₈ to R ₁₁ in the above formulas (B1), (B2), and (B6) include R ₁ to R ₄ in the above formula (A1), and An organic group similar to the organic group constituting R ₅ to R ₇ in the above formula (A2) can be used.

The upper limit value of Mw (weight average molecular weight) of the polymer according to this embodiment is, for example, 30000 or less, preferably 20000 or less, more preferably 14000 or less, and even more preferably 10,000 or less. preferable. Thereby, the mobility of a molecular chain improves and a more suitable crosslinked structure can be made.
Further, the lower limit value of the polymer Mw is, for example, 1500 or more, preferably 2000 or more, and more preferably 3000 or more. Thereby, when exposing a negative photosensitive resin composition, it becomes possible to form a crosslinked structure rapidly. Therefore, the sensitivity of the negative photosensitive resin composition can be improved.

In addition, the degree of dispersion of the polymer according to the present embodiment, that is, the upper limit value of Mw (weight average molecular weight) / Mn (number average molecular weight) is, for example, 2.5 or less and 2.2 or less. Preferably, it is 2.0 or less. Thereby, the width | variety of the molecular weight distribution of a polymer can be reduced, and the same crosslinked structure can be formed in the whole negative photosensitive resin composition. Therefore, the physical properties can be made uniform throughout the cured product of the negative photosensitive resin composition.
Moreover, the lower limit of Mw / Mn may be 1.0 or more, for example, and can be 1.5 or more. Mw / Mn is preferably closer to monodispersion.
Mw / Mn is a degree of dispersion indicating the width of the molecular weight distribution. By setting Mw / Mn of the polymer in the above range, the shape of the resin film made of the resin composition containing the polymer can be improved. Such an effect is particularly noticeable when the low molecular weight component of the polymer is simultaneously reduced as described above.

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 standard polystyrene (PS) calibration curve 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 alkali dissolution rate of the polymer in the present embodiment is, for example, not less than 500 kg / sec and not more than 20,000 kg / sec. The alkali dissolution rate of the polymer can be determined by, for example, dissolving a polymer in propylene glycol monomethyl ether acetate and applying a polymer solution adjusted to a solid content of 20% by weight on a silicon wafer by a spin method, followed by soft baking at 110 ° C. for 100 seconds. The polymer film thus obtained is impregnated with a 2.38% tetramethylammonium hydroxide aqueous solution at 23 ° C., and the time until the polymer film is visually erased is calculated.
By setting the alkali dissolution rate of the polymer to 500 kg / second or more, it is possible to improve the throughput in the development step using an alkali developer. Moreover, the residual film rate after the image development process by an alkali developing solution can be improved by making the alkali dissolution rate of a polymer into 20,000 kg / sec or less. For this reason, it is possible to suppress film loss due to the lithography process.

(Method for producing polymer)
The polymer according to this embodiment is produced, for example, as follows.
Polymerization step (Process S1) for polymerizing monomer A and monomer B to polymerize copolymer 1, and then the carboxyl group derived from monomer A of copolymer 1 has a terminal unsaturated carbon double bond It includes at least a substitution step (treatment S2) for obtaining a copolymer 2 by substitution with a compound and a low molecular weight removal step (treatment S3) for removing a low molecular weight component from the copolymer 2 to obtain a polymer.
When monomer B contains maleic anhydride, after the polymerization step (treatment S1) and before the low molecular weight removal step (treatment S3), a ring-opening step (treatment) S′1) and then a cleaning step (processing S′2) for removing residual metal components may be included.
Details of each step will be described below.

(Polymerization step (Process S1))
First, a norbornene type monomer substituted with a carboxyl group and maleic anhydride, maleimide or a maleimide derivative are prepared.
In the copolymer represented by the above formula (1), the norbornene type monomer substituted with the carboxyl group (hereinafter referred to as monomer A) is derived from the structural unit represented by A. Further, one or more monomers selected from the group consisting of maleic anhydride, maleimide and maleimide derivatives (hereinafter referred to as monomer B) are derived from the structural unit represented by B.

Monomer A is represented by the following formula (2). In the following formula (2), R ₅ to R ₇ can be the same as those in the above-described formula (A2).

(In the formula (2), R ₅ , R ₆ and R ₇ are each independently hydrogen or an organic group having 1 to 30 carbon atoms, and n is 0, 1 or 2.)

Specific examples of the norbornene-type monomer substituted by the carboxyl group represented by the above formula (2) include 5-norbornene-2-carboxylic acid, 5-norbornene-2,3-dicarboxylic acid, and tetracyclododecenecarboxylic acid. An acid etc. are mentioned.
As the norbornene type monomer substituted with a carboxyl group, one or more of these can be used. Of these, 5-norbornene-2-carboxylic acid is preferably used from the viewpoint of improving heat resistance.

Monomer B is one or more monomers selected from the group consisting of maleic anhydride, maleimide and maleimide derivatives, and one or more monomers selected from the group consisting of maleimide and maleimide derivatives. Preferably there is. By using a maleimide derivative, the heat resistance, the remaining film ratio after curing, and the solvent resistance can be improved. Further, by using maleimide and a maleimide derivative in combination, the alkali dissolution rate of the negative photosensitive resin composition can be improved, and further the sensitivity can be improved.
The maleimide derivative is represented by the following formula (3).

(In Formula (3), R ₁₁ is independently an organic group having 1 to 30 carbon atoms.)

Examples of maleimide derivatives represented by the above formula (3) include N-linear alkylmaleimides such as N-methylmaleimide and N-ethylmaleimide; N-branched alkylmaleimides such as N-isopropylmaleimide; N-cyclohexylmaleimide And N-arylmaleimide such as N-phenylmaleimide and N-naphthylmaleimide. Among these, linear N-alkylmaleimide, branched alkylmaleimide or N-cycloalkylmaleimide is preferably used, and N-cycloalkylmaleimide is more preferably included. As N-cycloalkalemaleimide, N-cyclohexylmaleimide is preferably used. Thereby, heat resistance, the remaining film rate after hardening, and solvent resistance can be improved.

Next, the copolymer 1 is synthesized by addition polymerization of the monomer A and the monomer B.
The method of addition polymerization is not particularly limited, but in this embodiment, the copolymer 1 is synthesized by radical polymerization.
By addition polymerization, copolymer 1 having a structural unit derived from monomer A and a structural unit derived from monomer B can be synthesized.
Here, the structural unit derived from the monomer A is represented by the following formula (A2).
Further, by using maleic anhydride, maleimide, and a maleimide derivative as the monomer B, the copolymer 1 having structural units derived from the following formula (B3), the following formula (B5), and the following formula (B6), respectively. Obtainable.

(In the formula (A2), R ₅ , R ₆ and R ₇ are each independently hydrogen or an organic group having 1 to 30 carbon atoms, and n is 0, 1 or 2.)

(In Formula (B6), R ₁₁ is independently an organic group having 1 to 30 carbon atoms.)

The molar ratio of monomer A to monomer B is preferably 0.5: 1 to 1: 0.5. Among these, from the viewpoint of controlling the molecular structure, the molar ratio is preferably 1: 1.
Monomer A, monomer B, and a polymerization initiator are dissolved in a solvent, and then heated for a predetermined time to cause addition polymerization to proceed. The heating temperature is, for example, 50 to 80 ° C., and the heating time is 10 to 20 hours.

As the polymerization initiator, one or more of azo compounds and organic peroxides can be used.
Examples of the azo compound include azobisisobutyronitrile (AIBN), dimethyl 2,2′-azobis (2-methylpropionate), 1,1′-azobis (cyclohexanecarbonitrile) (ABCN). Any one or more of these can be used.
Examples of the organic peroxide include hydrogen peroxide, ditertiary butyl peroxide (DTBP), benzoyl peroxide (benzoyl peroxide, BPO), and methyl ethyl ketone peroxide (MEKP). Any one or more of them can be used.

The amount (number of moles) of the polymerization initiator is 1% to the total number of moles of the norbornene-type monomer substituted with the carboxyl group derived from the structural unit A and the monomer derived from the structural unit B. 10% is preferable. The weight average molecular weight (Mw) of the resulting polymer can be adjusted to 5000-30000 by appropriately setting the amount of the polymerization initiator within the above range and appropriately setting the reaction temperature and reaction time.

As the solvent, for example, one or more of diethyl ether, tetrahydrofuran, toluene and the like can be used.

By this polymerization step, copolymer 1 which is a copolymer of monomer A and monomer B can be polymerized. The arrangement | sequence of the copolymer 1 is not specifically limited, Any of a random copolymer, an alternating copolymer, a block copolymer, and a periodic copolymer may be sufficient.
For example, when the monomer represented by the above formula (2) is used as the monomer A and the monomer represented by the above formula (3) is used as the monomer B, the copolymer 1 is represented by the following formula (4). A copolymer having a structural unit is formed.

(In the formula (4), R ₅ to R ₇ are the same as the above formula (A2). Also, R ₁₁ is the same as the above formula (3).)

In the copolymer 1, the functional groups of R ₅ to R ₇ derived from the monomer A may be different in each repeating unit or may be common. Among these, it is preferable that they are common. Thereby, the patterning precision of a negative photosensitive resin composition can be improved.

(Replacement step (S2))
Next, in the obtained copolymer 1, some of the carboxyl groups of the structural units represented by the above formula (A2) are substituted with a compound having a terminal unsaturated carbon double bond to obtain a copolymer 2.

Although the method for substituting the copolymer 1 and synthesizing the copolymer 2 is not particularly limited, for example, the following method can be used.
The copolymer 1 and the compound having a terminal unsaturated carbon double bond are dissolved in a solvent and heated for a predetermined time, whereby the substitution reaction proceeds to synthesize the copolymer 2. Here, the heating temperature is, for example, 50 to 100 ° C., and the heating time is 2 to 20 hours.
Thereby, in the structural unit of A, a common unit comprising a repeating unit derived from the monomer A, a repeating unit in which the monomer A is substituted with a compound having a terminal unsaturated carbon double bond, and a structural unit derived from the monomer B. Polymer 2 can be obtained.
A structural unit in which the monomer A is substituted with a compound having a terminal unsaturated carbon double bond is shown in the following formula (A1).

(In the 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, and at least R ₁ , R ₂ , R ₃ and R ₄ Contains one terminal unsaturated carbon double bond, n is 0, 1 or 2)

As the compound having a terminal unsaturated carbon double bond, an acrylic compound is preferably used.
Examples of the acrylic compound include methacrylic acid methacrylic acid (glycidyl methacrylate), glycidyl acrylate, 4-hydroxybutyl acrylate glycidyl ether, hydroxyethyl methacrylate, and the like. Among these, it is preferable to use glycidyl methacrylate.

As the solvent, for example, one or more of diethyl ether, tetrahydrofuran, toluene and the like can be used.

In the copolymer 2, for example, it is preferable to replace 5 mol% or more of structural units with the structural unit represented by the above formula (A1) with respect to all the structural units represented by A, and to replace 10 mol% or more. It is more preferable to substitute 15 mol% or more, and it is more preferable to substitute 20 mol% or more. By setting the substitution rate in this way, the terminal unsaturated carbon double bond derived from the norbornene unit can be appropriately crosslinked. Thereby, the heat resistance of the negative photosensitive resin composition containing the copolymer 2 and a residual film rate and solvent resistance can be improved.

Here, substitution of some of the repeating units derived from the norbornene-type monomer substituted with a carboxyl group can be identified by spectral data of 1H-NMR measurement.

Moreover, the substitution rate which substituted the carboxyl group with the acrylic compound can be measured as follows.
The polymer solution of copolymer 2 is subjected to 1H-NMR measurement. For the spectral data obtained by 1H-NMR measurement, the signal integral value X per unit proton derived from the carboxyl group and the signal per unit proton derived from the terminal unsaturated carbon double bond formed by the added acrylic compound. An integral value Y is calculated. Using the signal integration value, the substitution rate can be calculated by the following equation.
Substitution rate (%) = Y / (X + Y) × 100

(Low molecular weight removal step (S3))
Next, the organic layer containing the copolymer 2 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 polymer containing the copolymer 2 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 polymer which has the copolymer 2 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 (processing S3), the extraction operation is preferably repeated until the content of low nuclei having a molecular weight of 1000 or less in the copolymer 2 is 1% or less. Thereby, the amount of the low molecular weight component in the first polymer can be reduced to a degree sufficient to suppress the deformation of the film pattern during curing.

In addition, when the monomer B contains maleic anhydride, the ring-opening step (S′1) and the washing step (S′2) are performed after the polymerization step (S1) and before the low molecular weight component removal step (S3). You may go. This will be described below.

(Ring opening process (S'1))
Among the maleic anhydrides of the obtained copolymer 1 or copolymer 2, the remaining repeating units are opened while some of the repeating units are in a closed state. Thereby, the quantity of the carboxyl group in the copolymer 1 can be adjusted. That is, the acid value of the produced polymer can be controlled.
In this embodiment, among the repeating units derived from maleic anhydride of Copolymer 1 or Copolymer 2, for example, 50% or more of the repeating units are not opened, and the cyclic structure (anhydrous Ring). That is, the ring opening rate of the copolymer 1 is, for example, less than 50%. Among these, it is preferable that 60% or more and 90% or less of the repeating units of the cyclic structure derived from maleic anhydride of the copolymer 1 are not ring-opened.

Here, the ring-opening rate of the repeating unit derived from maleic anhydride can be measured as follows.
The IR absorption intensity (A1) of (C═O) in the acid anhydride structure of copolymer 1 or copolymer 2 before ring opening was measured, and (C═O) in the acid anhydride structure after ring opening was measured. The ring opening rate is calculated from the IR absorption intensity (A2) by the following formula.
Ring-opening rate (%) = ((A1-A2) / A1) × 100
Acetonitrile is used as an internal standard substance.

In particular,
(A) One of the metal alkoxide (B) alcohol as the base and the alkali metal hydroxide as the base is added to the reaction solution obtained by polymerizing the copolymer 1 in the polymerization step, and methyl ethyl ketone. An organic solvent such as (MEK) is further added and stirred at 40 to 50 ° C. for 1 to 5 hours to obtain a reaction liquid L1. In the reaction liquid L1, a part of the anhydride ring of the repeating unit derived from the maleic anhydride of the copolymer 1 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 so, the amount of metal alkoxide or alkali metal hydroxide can be reduced, and the alkali metal concentration in the finally obtained polymer can be reduced.
By reducing the alkali metal concentration in the polymer, migration of metal ions can be suppressed when a device using this polymer is formed.

The metal alkoxide described above is preferably one represented by M (OR ₈ ) (M is a monovalent metal and R ₈ is an organic group having 1 to 18 carbon atoms). Examples of the metal M include alkali metals, and sodium is preferable from the viewpoint of handleability. The R _8, are the same as those for _{R 8} in example above formula (B1).
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 maleic anhydride-derived structure of copolymer 1 or copolymer 2 may be ring-opened in the presence of (B) 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 ₈ OH) is preferable. What was mentioned above can be used for R < ₈ > which is an organic group. R ₈ preferably has 30 or less carbon atoms.

The repeating unit derived from maleic anhydride opened in this ring-opening step (treatment S′1) has a structure represented by the following formula (6), and has a structure having a carboxyl group salt moiety.

When the copolymer is opened with (A) a metal alkoxide as a base, or (B) an alcohol and an alkali metal hydroxide as a base, the following formulas (8), ( The structure shown in B2) may be formed. In the following formula (B2), R ₉ and R ₁₀ may be the same as R ₈ described above.

Next, an acidic aqueous solution such as hydrochloric acid or formic acid is added to the reaction liquid L1, whereby the copolymer 1 or the copolymer 2 is acid-treated to replace the metal ions (Na +) with protons (H +).
The structural units represented by the above formulas (6) and (8) become structural units represented by the following (B1) and (B4) by proton substitution, respectively.

In this ring-opening step (treatment S′1), it is preferable that 50% or more of the repeating units derived from maleic anhydride of Copolymer 1 or Copolymer 2 are not opened. In the copolymer 2, as described above, a metal (for example, 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 polymer can be reduced. Thereby, the quantity of the alkali metal in the polymer finally obtained by this embodiment can be reduced, and a desired characteristic can be exhibited in the negative photosensitive resin composition using this polymer.

(Washing process (Processing S'2))
When the ring-opening step (treatment S′1) is performed, the solution containing the copolymer 1 or the copolymer 2 after the ring-opening obtained in the step is mixed with water and an organic solvent (for example, methyl ethyl ketone). To remove residual metal components. The copolymer 1 or the copolymer 2, the residual monomer and the 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 step (processing S′2) 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 1 or the copolymer 2 after ring-opening can fully be reduced.
In addition, it is preferable to repeat a washing | cleaning process (process S3) so that the alkali metal concentration in the copolymer 1 or the copolymer 2 after ring-opening may be 10 ppm or less, Preferably it is 5 ppm or less.

In this embodiment, the negative photosensitive resin composition can contain the polymer, a photosensitive agent, and a crosslinking agent. Furthermore, an additive such as a solvent and an adhesion improving agent or a surfactant can be contained.

In this embodiment, the upper limit of the polymer content is 80 parts by mass or less, preferably 75 parts by mass or less, with respect to 100 parts by mass of the total solid content of the negative photosensitive resin composition. It is still more preferable that it is below mass parts.
Further, the lower limit of the content of the polymer is 5 parts by mass or more, preferably 10 parts by mass or more, and 20 parts by mass or less with respect to 100 parts by mass of the total solid content of the negative photosensitive resin composition. More preferably.
When the content of the polymer is within the above upper and lower limits, it is possible to form an appropriate crosslinked structure by exposing the negative photosensitive resin composition.

(Photosensitive agent)
In the present embodiment, a radical photopolymerization initiator can be used as the photosensitive agent.
Specific examples of the radical photopolymerization initiator include alkylphenone type initiators, oxime ester type initiators, acylphosphine oxide type initiators, and the like. As a radical photopolymerization initiator, one or a combination of two or more of the above specific examples can be used. Among these, it is preferable to use an oxime ester type radical photopolymerization initiator. Thereby, the photosensitive agent can be radicalized with a low exposure amount, and the sensitivity can be increased.

Specific photo radical polymerization initiators include, for example, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-methyl-1 [4- (methylthio) phenyl] -2-Morifolinopropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2- Methyl-1-propan-1-one, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyl) Oxime)), ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (0-acetylo Shim), and the like. Among these, you may use 1 type, or 2 or more types.

In this embodiment, the upper limit of the content of the photosensitive agent may be 1 part by mass or more, preferably 1.5 parts by mass or more, and preferably 2 parts by mass or more with respect to 100 parts by mass of the polymer. More preferably it is. Thereby, in a negative photosensitive resin composition, the reaction rate by exposure can be improved. Therefore, sensitivity can be improved.
Further, the lower limit of the content of the photosensitive agent is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 10 parts by mass or less. Thereby, in a negative photosensitive resin composition, appropriate reactivity with respect to a polymer can be expressed.

(Crosslinking agent)
In the present embodiment, a known crosslinking agent can be used as the crosslinking agent. As the crosslinking agent, for example, an acrylic crosslinking agent containing a (meth) acryl group is preferably used. The acrylic crosslinking agent is, for example, a polyfunctional acrylic compound. Here, the polyfunctional acrylic compound is a compound having two or more (meth) acryl groups.
In addition, in this embodiment, a (meth) acryl group shows an acryl group or a methacryl group, ie, a methacryl group. The acrylic group includes an acrylate group. The methacryl group includes a methacrylate group, that is, a methacrylate group.
Here, as a combination of the crosslinking agent and the terminal unsaturated carbon double bond of the copolymer, for example,
The crosslinking agent is preferably an acrylic crosslinking agent, and the functional group having a terminal unsaturated carbon double bond of the copolymer preferably includes a structure represented by the general formula (E1) or the general formula (E2). Thereby, the reactivity of the radical chain reaction of a crosslinking agent and a copolymer can be maintained at the same level. Therefore, a suitable cross-linked structure can be formed.

Specific polyfunctional acrylic compounds include trifunctional (meth) acrylates such as trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and ditrimethylolpropane tetra (meth). Examples include tetrafunctional (meth) acrylates such as acrylate and hexafunctional (meth) acrylates such as dipentaerythritol hexa (meth) acrylate. Among these, you may use 1 type, or 2 or more types.
In addition, in this embodiment, a (meth) acrylate group shows an acrylate group or a methacrylate group.

In the present embodiment, the lower limit value of the content of the crosslinking agent may be 20 parts by mass or more, preferably 25 parts by mass or more, and 30 parts by mass or more with respect to 100 parts by mass of the polymer. Is more preferable. Thereby, in addition to the crosslinked structure derived from the terminal unsaturated carbon double bond of the norbornene-type structural unit, a crosslinked structure can be formed. Therefore, improvement in heat resistance, improvement in solvent resistance, and improvement in the remaining film ratio after development can be realized.
Further, the upper limit of the content of the crosslinking agent may be 80 parts by mass or less, preferably 75 parts by mass or less, and more preferably 70 parts by mass or less with respect to 100 parts by mass of the polymer. . Thereby, it can prevent that a crosslinking agent contributes to a crosslinked structure excessively, and can suppress the mobility of a norbornene-type structural unit appropriately. Therefore, improvement in heat resistance, improvement in solvent resistance, and improvement in the remaining film ratio after development can be realized.

(solvent)
The negative 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 -3-Methoxypropionate and the like.
Of these compounds, γ-butyrolaclone, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether are among these compounds from the viewpoint of significantly suppressing the occurrence of cracks in the resin film. It is preferable to use a compound selected from the group consisting of propylene glycol monomethyl ether acetate.

(Other additives)
In the present embodiment, the negative photosensitive resin composition is added as necessary, such as an adhesion improving agent, a surfactant, an antioxidant, a filler, a sensitizer, a silane coupling agent, and a terminal blocking agent. An agent may be included.

The resin film according to the present embodiment is made of a cured product of a negative photosensitive resin composition.

The resin film of this embodiment consists of the said negative photosensitive resin composition, and can be comprised with these dry films or cured films.
The negative photosensitive resin composition of this 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 obtained by applying a negative photosensitive resin composition by spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, or the like, and removing the solvent. Consists of a membrane.
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. The permanent film can be used, for example, as a protective film, an interlayer film, or a dam material.

The resin film is used in the electronic device according to the present embodiment.

The electronic device 100 of the present embodiment can include the above resin film.
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 provided on the semiconductor substrate (not shown). 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, 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.
In the present embodiment, one or more of the passivation film 32, the insulating layer 42, and the insulating layer 44 may be formed of a resin film formed by curing, for example, the above-described negative photosensitive resin composition. it can. In this case, for example, the coating film formed of a negative photosensitive resin material is exposed to ultraviolet light, patterned by performing development, and then heated and cured to thereby passivate the passivation film 32, the insulating layer 42, or the insulating layer. 44 is formed.

In the opening provided in the insulating layer 44, for example, a bump 52 is formed via a 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 embodiment, and modifications, improvements, etc. 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.

(Synthesis Example 1)
A copolymer is prepared by charging 5-norbornene-2-carboxylic acid and N-cyclohexylmaleimide at a molar ratio of 50/50, and adding glycidyl methacrylate to the copolymer. A polymer was synthesized and designated as Synthesis Example 1. Details will be described below.
To a suitably sized reaction vessel equipped with a stirrer and a condenser, 5-norbornene-2-carboxylic acid (NC, manufactured by Honshu Chemical Industry Co., Ltd., 87.7 g, 0.630 mol) and dimethyl 2,2′- Azobis (2-methylpropionate) (V-601, manufactured by Wako Pure Chemical Industries, Ltd., 14.5 g, 63 mmol) was weighed and dissolved in methyl ethyl ketone (MEK, 58.0 g) to prepare a solution. The dissolved solution was purged with nitrogen for 10 minutes to remove oxygen, and then reacted at 70 ° C. for 6 hours with stirring. During the 6-hour reaction, a mixed solution of N-cyclohexylmaleimide (CMI, manufactured by Nippon Shokubai Co., Ltd., 112.9 g, 0.630 mol) and MEK 127.5 g was continuously added to the reaction vessel over 6 hours. After the addition of the mixture of CMI was completed, the mixture was further reacted at 70 ° C. for 3 hours. After diluting the reaction solution by adding 266.7 g of MEK, the solution was added dropwise to a large amount of methanol / water mixture (weight ratio 8/2) to precipitate a solid. The solid collected by filtration was dried in a vacuum dryer at 50 ° C. for 16 hours to obtain a polymer which is a copolymer of 5-norbornene-2-carboxylic acid and N-cyclohexylmaleimide. The yield was 128.1 g, Mw was 4,700, and Mw / Mn was 1.63.
A polymer (60.0 g), which is a copolymer of the above-mentioned 5-norbornene-2-carboxylic acid and N-cyclohexylmaleimide, is weighed into a reaction vessel of an appropriate size equipped with a stirrer and a condenser. (140.0 g). Further, glycidyl methacrylate (GMA, manufactured by Tokyo Chemical Industry Co., Ltd., 20.7 g, 0.146 mol) and triethylamine (1.8 g) were added and heated at 80 ° C. for 5 hours. After formic acid was added to the reaction solution for acid treatment, the solution was added dropwise to a large amount of methanol / water mixture (weight ratio 8/2) to precipitate the polymer of Synthesis Example 1. The solid collected by filtration was dried in a vacuum dryer at 40 ° C. for 40 hours to obtain the polymer of Synthesis Example 1. The yield was 50.5 g, Mw was 5,500, and Mw / Mn was 1.65.

The obtained polymer of Synthesis Example 1 was dissolved in heavy DMSO, and 1H-NMR measurement was performed using a nuclear magnetic resonance apparatus manufactured by JEOL. From the spectrum obtained by 1H-NMR measurement, a signal derived from the methacryloyl group of the added GMA was confirmed at δ5.68 and δ6.07, and a signal derived from the carboxyl group in the polymer was confirmed at δ12.13.
In addition, from the integration ratio of each signal, it was confirmed that the molar ratio of the carboxyl group to the methacryloyl group was 1: 0.3.
As a result, it was confirmed that the carboxyl groups in some structural units derived from 5-norbornene-2-carboxylic acid were substituted with glycidyl methacrylate. Therefore, in Synthesis Example 1, it was confirmed that a copolymer having each structural unit represented by the following formula (9) was obtained.

(Synthesis Example 2)
By adding 5-norbornene-2-carboxylic acid, maleimide, and N-cyclohexylmaleimide at a molar ratio of 50/15/35, a copolymer was prepared, and glycidyl methacrylate was added to the copolymer. Then, a polymer which is a copolymer was synthesized and used as Synthesis Example 2. Details will be described below.
In a suitably sized reaction vessel equipped with a stirrer and a condenser, 5-norbornene-2-carboxylic acid (NC, manufactured by Honshu Chemical Industry Co., Ltd., 70.8 g, 0.512 mol), N-cyclohexylmaleimide (CMI) Nippon Shokubai Co., Ltd., 14.23 g, 0.079 mol) and dimethyl 2,2′-azobis (2-methylpropionate) (V-601, manufactured by Wako Pure Chemical Industries, Ltd., 11.8 g) 51 mmol) was weighed and dissolved in methyl ethyl ketone (MEK, 47.2 g) to prepare a solution. The dissolved solution was purged with nitrogen for 10 minutes to remove oxygen, and then reacted at 70 ° C. for 6 hours with stirring. During the reaction for 6 hours, a mixed solution of maleimide (14.9 g, 0.154 mol), CMI (50.1 g, 0.279 mol) and MEK 91.0 g was continuously added to the reaction vessel over 6 hours. After the addition of the solution was completed, the mixture was further reacted at 70 ° C. for 3 hours. After 200 g of MEK was added to the reaction solution for dilution, it was added dropwise to a large amount of methanol / water mixture (weight ratio 5/5) to precipitate a solid. The solid collected by filtration was dried in a vacuum dryer at 50 ° C. for 64 hours to obtain a polymer which is a copolymer of 5-norbornene-2-carboxylic acid, maleimide and N-cyclohexylmaleimide. The yield was 124.3 g, Mw was 4,500, and Mw / Mn was 1.75.
A polymer (50.0 g), which is a copolymer of the above-mentioned 5-norbornene-2-carboxylic acid, maleimide, and N-cyclohexylmaleimide, is weighed in an appropriately sized reaction vessel equipped with a stirrer and a condenser. And dissolved in PGMEA (100.0 g). Furthermore, glycidyl methacrylate (GMA, manufactured by Tokyo Chemical Industry Co., Ltd., 24.3 g, 0.171 mol) and triethylamine (1.5 g) were added and heated at 90 ° C. for 4 hours. After formic acid was added to the reaction solution for acid treatment, it was dropped into a large amount of methanol / water mixture (weight ratio 5/5) to precipitate the polymer of Synthesis Example 2. The solid collected by filtration was dried in a vacuum dryer at 40 ° C. for 40 hours to obtain the polymer of Synthesis Example 2. The yield was 31.2 g, Mw was 4,900, and Mw / Mn was 1.72.

The obtained polymer of Synthesis Example 2 was dissolved in heavy DMSO, and 1H-NMR measurement was performed using a nuclear magnetic resonance apparatus manufactured by JEOL. Similar to Synthesis Example 1, a peak derived from the carboxyl group and a peak derived from the structure of the methacryloyl group were confirmed. As a result, it was confirmed that the carboxyl groups in some structural units derived from 5-norbornene-2-carboxylic acid were substituted with glycidyl methacrylate. Therefore, in Synthesis Example 2, it was confirmed that a copolymer having each structural unit represented by the following formula (10) was obtained.

(Synthesis Example 3)
2-Norbornene and maleic anhydride are charged at a molar ratio of 50/50 to prepare a copolymer, and the structural unit derived from maleic anhydride of the copolymer is ring-opened with sodium acetate to obtain glycidyl methacrylate. Was added to synthesize a polymer as a copolymer, which was designated as Synthesis Example 3. Details will be described below.
In a suitably sized reaction vessel equipped with a stirrer and a condenser, maleic anhydride (Nippon Shokubai Co., Ltd., 122.4 g, 1.25 mol), 2-norbornene (75 wt% toluene solution, Maruzen Petrochemical Co., Ltd. 8 g, 1.25 mol) and dimethyl 2,2′-azobis (2-methylpropionate) (V-601, manufactured by Wako Pure Chemical Industries, 11.5 g, 50 mmol) were weighed and methyl ethyl ketone (MEK, 150 0.8 g) and toluene (38.5 g) to prepare a solution. The solution was purged with nitrogen for 10 minutes to remove oxygen, and then heated to 60 ° C. with stirring. After 16 hours, MEK (320 g) was added to dilute and cool. The reaction mixture was added dropwise to a large amount of methanol to precipitate a solid, which was filtered using a Nutsche, further washed with methanol, and the solid was collected by filtration. The obtained solid was vacuum dried at 70 ° C. to obtain a copolymer of 2-norbornene and maleic anhydride. The yield was 208.1 g, the weight average molecular weight (Mw) was 11,100, and the dispersity (Mw / Mn) was 2.25.
The above-mentioned copolymer of 2-norbornene and maleic anhydride (10.0 g) was weighed and dissolved in MEK (30.0 g) in an appropriately sized reaction vessel equipped with a stirrer and a condenser. Further, 2-hydroxyethyl methacrylate (HEMA, Nippon Shokubai Co., Ltd., 8.5 g, 65 mmol) and sodium acetate (1.0 g) were added and heated at 70 ° C. for 8 hours. To this reaction solution, glycidyl methacrylate (GMA, 1.5 g, 10 mmol) was added, and the mixture was further stirred at 70 ° C. for 16 hours. After formic acid was added to the reaction solution for acid treatment, it was dropped into a large amount of pure water to precipitate a polymer. The solid collected by filtration was dried in a vacuum dryer at 40 ° C. for 16 hours to obtain the polymer of Synthesis Example 3. The yield was 11.5 g, Mw was 14,100, and Mw / Mn was 2.30.
In Synthesis Example 3, a copolymer having each structural unit represented by the following formula (13) was obtained.

(Acid value)
For each synthesis example, the acid value of the obtained polymer was calculated as follows.
About 0.2 g of the synthesized polymer was weighed and dissolved in 50 mL of a THF / methanol = 1/1 (v / v) solution. The obtained solution was subjected to potentiometric titration using a sodium methoxide / methanol solution having a concentration of 0.1M. In potentiometric titration, the acid value of the polymer was evaluated by the amount of reagent added up to the inflection point of the potential generated at the electrode.

(Alkali dissolution rate)
For each synthesis example, the alkali dissolution rate of the obtained polymer was measured as follows.
The polymer was dissolved in PGMEA to prepare a solution having a solid concentration of 25%. This polymer solution was applied onto a silicon wafer by a spin method, and this was soft baked at 100 ° C. for 120 seconds to form a polymer film having a thickness H of about 2.0 μm. The silicon wafer on which this polymer film was formed was impregnated with a 2.38%, 23 ° C. aqueous tetramethylammonium hydroxide solution, and the time T until the polymer film was visually erased was measured. From H and T, the alkali dissolution rate was calculated from the following equation.
(Alkali dissolution rate) [Å / second] = (film thickness H) / (time T until the polymer film is erased)

Table 1 below shows the evaluation results of acid value and alkali dissolution rate for the polymers of each synthesis example.

(Photosensitive agent)
Photosensitizer 1: A photoradical polymerization initiator represented by the following formula (11) (Irgacure OXE02 manufactured by BASF) was used.

(Crosslinking agent)
Crosslinking agent 1: An acrylic crosslinking agent (DPHA manufactured by Daicel Cytec Co., Ltd.) represented by the following formula (12) was used.

(Adhesion improver)
Adhesion improver 1: 3-glycidoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.)

(Surfactant)
Surfactant 1: Megafac F-556 (manufactured by DIC Corporation)

Next, the negative photosensitive resin composition produced in the examples of the present invention will be described.

(Adjustment of negative photosensitive resin compositions of Examples 1 and 2 and Comparative Example 1)
For each example and each comparative example, a 20% PGMEA solution of the polymer prepared in Synthesis Examples 1 to 3, a photosensitizer, a cross-linking agent, an adhesion improver, and a surfactant were added in appropriate amounts in the amounts shown in Table 2. And stirred. After stirring, the mixture was filtered through a 0.2 μm filter to prepare a negative resin composition.
In preparing the negative photosensitive resin composition of each example and each comparative example, PGMEA was adjusted so that the content of the resin component (total of phenol resin and polymer) was 30%.

(5% weight loss temperature)
About each Example and each comparative example, 5% weight reduction | decrease temperature in the temperature rising process after hardening was evaluated as follows using the obtained negative photosensitive resin composition.
First, after applying a negative photosensitive resin composition to a 6-inch wafer, the solvent was removed by heat treatment at 80 ° C. for 90 seconds. Next, the negative photosensitive resin composition was heat-treated in an oven to cure the photosensitive resin composition. In the heat treatment, the inside of the oven on which the wafer is placed is replaced with nitrogen at 30 ° C. for 30 minutes, and the temperature is raised to a curing temperature (200 ° C.) at a heating rate of 5 ° C./min. C.) for 30 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. In this way, a cured film cured at a curing temperature of 200 ° C. was obtained for each of the examples and comparative examples.
Next, the 5% weight loss temperature (° C.) of the sample was measured. The measurement was performed on a sample obtained by weighing 10 mg of the cured film using a thermogravimetric / differential calorimeter (TG / DTA), a starting temperature of 30 ° C., a measuring temperature range of 30 to 500 ° C., and a heating rate of 5 The measurement was performed under the conditions of ° C / min. The temperature at which the weight of the weighed sample was reduced by 5% was defined as a 5% weight reduction temperature.

(Residual film rate after curing)
About each Example and each comparative example, the remaining film rate after hardening was evaluated as follows using the obtained negative photosensitive resin composition.
The obtained negative photosensitive resin composition was spin-coated on a 4-inch silicon wafer treated with HMDS (Hexamethyldisilazane) and baked on a hot plate at 110 ° C. for 100 seconds to obtain a thin film A having a thickness of about 3.0 μm. . For this thin film A, a g + h + i line mask aligner (PLA-501F) manufactured by Canon Co., Ltd. was used, and a 10 μm line and space width of 1: 1 mask were used, and a pattern dimension of 10 μm line and space width was 1: 1. The line and space width is 1: 1 by exposing the g + h + i line at an optimal exposure amount (50 mJ / cm 2) and developing with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 90 seconds. A thin film B with a pattern was obtained.
From the film thicknesses of the thin film A and the thin film B obtained by the above method, the remaining film ratio was calculated from the following formula.
Residual film ratio after curing (%) = {(film thickness of thin film B (μm)) / (film thickness of thin film A (μm))} × 1
00

(Solvent resistance)
About each Example and each comparative example, solvent resistance was evaluated as follows using the obtained negative photosensitive resin composition.
The obtained negative photosensitive resin composition was spin-coated on a 1737 glass substrate made by Corning 100 mm long and 100 mm wide, baked on a hot plate at 110 ° C. for 100 seconds, and with a thin film having a thickness of about 3.0 μm. A glass substrate was obtained.
The glass substrate with a thin film was immersed in N-methylpyrrolidone (Kanto Chemical Co., Inc.) at room temperature (25 ° C.) for 10 minutes, and then rinsed with pure water. The film thickness change rate defined by the following arithmetic expression was calculated.
Change rate of film thickness (%) = [{(film thickness after solvent immersion) − (film thickness before solvent immersion)} / (film thickness before solvent immersion)] × 100

(sensitivity)
About each Example and each comparative example, the sensitivity evaluation was performed as follows using the obtained negative photosensitive resin composition.
The obtained negative photosensitive resin composition 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 3.0 μm. This 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 ) at 1: 1 was defined as sensitivity.

As shown in Table 1, it was confirmed that Synthesis Examples 1 and 2 were copolymers having an appropriate acid value and alkali dissolution rate.
In addition, as shown in Table 2, the negative photosensitive resin composition of Example 1 has higher heat resistance, post-curing residual film ratio, and solvent resistance than the negative photosensitive resin composition of Comparative Example 1. It was confirmed that it improved. Furthermore, the negative photosensitive resin composition of Example 2 has improved heat resistance, a post-curing residual film ratio and solvent resistance as compared with the negative photosensitive resin composition of Comparative Example 1, and further improved sensitivity. It was confirmed that it was retained.

This application claims priority based on Japanese Patent Application No. 2017-002022 filed on January 10, 2017, the entire disclosure of which is incorporated herein.

Claims (13)

1. A polymer which is a copolymer represented by the following formula (1);
   A crosslinking agent;
   A negative photosensitive resin composition comprising a photosensitive agent.
   

   

   (In the formula (1),
   l and m represent the molar content in the polymer,
   l + m = 1,
   A is a structural unit represented by the following formula (A1);
   A structural unit represented by the following formula (A2):
   B includes at least one structural unit represented by the following formula (B1), the following formula (B2), the following formula (B3), the following formula (B4), the following formula (B5), or the following formula (B6). )
   

   

   (In the 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, and at least R ₁ , R ₂ , R ₃ and R ₄ Contains one terminal unsaturated carbon double bond, n is 0, 1 or 2)
   

   

   (In the formula (A2), R ₅ , R ₆ and R ₇ are each independently hydrogen or an organic group having 1 to 30 carbon atoms, and n is 0, 1 or 2.)
   

   

   (In formula (B1), R ₈ is independently an organic group having 1 to 30 carbon atoms.)
   

   

   (In Formula (B2), R ₉ and R ₁₀ are each independently an organic group having 1 to 30 carbon atoms.)
   

   

   

   

   

   (In Formula (B6), R ₁₁ is independently an organic group having 1 to 30 carbon atoms.)
2. In the negative photosensitive resin composition according to claim 1,
   The negative photosensitive resin composition in which the structural unit represented by B of the copolymer includes a structural unit represented by the above formula (B6).
3. In the negative photosensitive resin composition according to claim 1 or 2,
   The negative photosensitive resin composition in which the structural unit represented by B of the copolymer includes a structural unit represented by the formula (B6) and a structural unit represented by the formula (B5).
4. The negative photosensitive resin composition according to any one of claims 1 to 3,
   In the structural unit represented by the above formula (A1) of the copolymer, at least one of R ₁ , R ₂ , R ₃ and R ₄ is represented by the following general formula (E1) as a terminal unsaturated carbon double bond: Negative photosensitive resin composition containing the structural unit shown.
   

   

   (In the formula (E1), R _e is independently hydrogen or an organic group having 1 to 10 carbon atoms.)
5. The negative photosensitive resin composition according to any one of claims 1 to 4, wherein
   The negative photosensitive resin composition, wherein the crosslinking agent is an acrylic crosslinking agent containing a (meth) acryl group.
6. It is a negative photosensitive resin composition according to any one of claims 1 to 5,
   The negative photosensitive resin composition, wherein the content of the crosslinking agent is 20 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the polymer.
7. The negative photosensitive resin composition according to any one of claims 1 to 6,
   The negative photosensitive resin composition, wherein the polymer content is 5 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the total solid content of the negative photosensitive resin composition.
8. The negative photosensitive resin composition according to any one of claims 1 to 7,
   The content of the structural unit represented by the above formula (A1) of the copolymer is 0.1 mol or more and 3.0 mol or less with respect to 1.0 mol of the structural unit represented by the above formula (A2). Photosensitive resin composition.
9. The negative photosensitive resin composition according to any one of claims 1 to 8,
   The negative photosensitive resin composition, wherein the photosensitive agent is a radical photopolymerization initiator.
10. It is a negative photosensitive resin composition according to any one of claims 1 to 9,
    The negative photosensitive resin composition, wherein the polymer has a weight average molecular weight of 1500 or more and 30000 or less.
11. It is a negative photosensitive resin composition according to any one of claims 1 to 10,
    The negative photosensitive resin composition, wherein the degree of dispersion of the polymer is 1.0 or more and 2.5 or less.
12. A resin film comprising a cured product of the negative photosensitive resin composition according to any one of claims 1 to 11.
13. An electronic device using the resin film according to claim 12.

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