JP2023159232A - Photosensitive resin composition and lens - Google Patents

Abstract

To provide a photosensitive resin composition capable of forming a positive resist film with an optimal balance between transparency and heat-resistant shape retention.SOLUTION: A photosensitive resin composition comprises a polymer having a monomer unit (I), a polyamide-imide having a branched structure, and a sulfonic acid compound containing a naphthylimide group, wherein R1 is a single bond or an optionally substituted, C1-6 divalent hydrocarbon group and R2 is a hydrogen atom or an optionally substituted, C1-6 monovalent hydrocarbon group.SELECTED DRAWING: None

Description

The present invention relates to a photosensitive resin composition and a lens.

Resin films having various functionalities can be provided on electronic components such as light receiving elements such as various sensors, light emitting elements, and touch panels that can include both of these elements. Micro LEDs (Light Emitting Diodes), micro OLEDs (Organic Light Emitting Diodes), and organic electroluminescent elements (hereinafter also referred to as "organic EL elements"), which are examples of light emitting elements, are made of various resins depending on the purpose. A membrane may be provided. Such resin films include, for example, a protective film to prevent element deterioration and damage, an electrical insulating film to maintain electrical insulation, and a passivation film to protect the inside from external moisture and metal ions. Examples include membranes. Note that the resin film can be expressed by various names depending on the function it exhibits. For example, a resin film that performs a protective function and an electrical insulation function may be referred to as a "protective insulating film" or the like.

Conventionally, thermosetting resin materials such as epoxy resins have been generally used as resin materials for forming these resin films. Note that in forming the protective film, the electrical insulating film, and the passivation film, it has also been common practice to use inorganic materials such as silicon dioxide, aluminum oxide, and silicon nitride instead of resin materials. In recent years, with the increasing demand for higher density wiring and higher brightness for light emitting elements, resin materials used to form resin films are required to have high transparency. .

In order to meet such demands, photosensitive resin compositions using various resin materials have been proposed. For example, Patent Document 1 discloses a photosensitive composition containing a polymer made of a specific vinyl compound, a polymerizable compound, a photopolymerization initiator, and a solvent. According to such a photosensitive composition, a microlens with excellent refractive index, transparency in the visible region, and heat resistance can be formed. Furthermore, in Patent Document 2, a resin obtained by partially hydrogenating a vinylphenol copolymer, a 1,2-naphthoquinonediazide sulfonic acid ester as a photosensitizer, and a heat-resistant and solvent-resistant resin used when forming a lens by heat treatment. A photosensitive material comprising a thermosetting agent and a solvent capable of imparting properties is disclosed. According to such a photosensitive material, it is possible to form a lens having a large refractive index and excellent transparency in the visible light region, heat resistance, light resistance, and solvent resistance.

JP2009-216727A Japanese Unexamined Patent Publication No. 7-168359

Here, the resin film provided on the various electronic components described above may have a pattern. Here, when the resin film "has a pattern", for example, the resin film has a shape corresponding to the lens shape of the lens provided in the light-receiving element, the light-emitting element, etc. as described above, that is, the "pattern". It may be formed by a film. In other words, in a resin film having a pattern, the shape of the resin film itself may be such that it can function as a lens. In general, a "resin film having a pattern (hereinafter also referred to as a "patterned resin film")" refers to a coating film made of a resin composition formed using a resin composition. It can be formed by performing a heating process (hereinafter referred to as a "post-bake process") after a patterning process or the like. Hereinafter, the coating film and the resin film may be collectively referred to as a "resist film." Note that the patterned resin film obtained through the post-baking process may be further exposed to heat treatment in the process of forming peripheral structures such as wiring. Here, in the post-baking process and other heating processes, if the shape obtained in the patterning process is excessively deformed, there is a possibility that the desired function cannot be imparted to the resin film. Therefore, resist films such as paint films and resin films are required to have excellent heat-resistant shape retention in addition to excellent transparency.

However, the coating film or resist film formed when manufacturing microlenses or lenses using the photosensitive composition described in Patent Document 1 and the photosensitive material described in Patent Document 2 has a lack of transparency and heat resistance. There was room for improvement in terms of achieving both a high level of shape retention.

Therefore, an object of the present invention is to provide a photosensitive resin composition capable of forming a positive resist film that can achieve both high levels of transparency and heat-resistant shape retention. Another object of the present invention is to provide a lens with excellent transparency and heat-resistant shape retention.

The present inventor conducted extensive studies in order to achieve the above object. The present inventor has discovered that when a photosensitive resin composition containing a polymer having a vinylphenol monomer unit, a polyamideimide having a branched structure, and a naphthylimide group-containing sulfonic acid compound is used, transparency can be improved. The present inventors have newly discovered that it is possible to form a positive resist film with excellent heat-resistant shape retention properties, and have completed the present invention.

That is, the present invention aims to advantageously solve the above problems, and the photosensitive resin composition of the present invention comprises a polymer having a monomer unit represented by the following general formula (I). , a polyamideimide having a branched structure, and a sulfonic acid compound containing a naphthylimide group. According to the photosensitive resin composition having such a specific composition, a positive resist film having excellent transparency and heat-resistant shape retention can be formed.
(In the general formula (I), R ¹ is a chemical single bond or a divalent hydrocarbon group having 1 to 6 carbon atoms which may have a substituent, and R ² is a hydrogen atom, or a monovalent hydrocarbon group having 1 to 6 carbon atoms which may have a substituent.)
In this specification, the "light" to which the "photosensitive resin composition" can be sensitive is not limited to so-called visible light, but includes a wide range of light that can be generally referred to as "radiation." Active energy rays in the wavelength range may be included.

Here, in the photosensitive resin composition of the present invention, it is preferable that the number average molecular weight of the polyamideimide having the branched structure is 2,000 or more and 30,000 or less. If the number average molecular weight of the polyamide-imide having a branched structure is 2000 or more, the heat-resistant shape retention of the positive resist film can be further improved, and the formation of a positive resist film using the photosensitive resin composition can be further improved. Ease of use can be increased. Further, if the number average molecular weight of the polyamideimide having a branched structure is 30,000 or less, the compatibility with the polymer having the monomer unit represented by the general formula (I) can be improved.

Furthermore, in the photosensitive resin composition of the present invention, it is preferable that the polymer is a copolymer further having a (meth)acrylate monomer unit. If the polymer is a copolymer further having a (meth)acrylate monomer unit, the sensitivity of the photosensitive resin composition can be improved and a positive resist film with excellent transparency can be formed. .
In addition, in this specification, "(meth)acrylate" means "acrylate and/or methacrylate."

Furthermore, in the photosensitive resin composition of the present invention, the content ratio of the polymer to the polyamide-imide having a branched structure (polymer: polyamide-imide having a branched structure) is 90:10 to 70 on a mass basis. :30 is preferable. If the content ratio of the polymer and polyamideimide having a branched structure (polymer: polyamideimide having a branched structure) is 90:10 to 70:30 on a mass basis, the resulting positive resist film will be transparent. It is possible to suppress a decrease in properties, prevent a decrease in residual film rate after development, improve heat-resistant shape retention, and prevent a decrease in sensitivity.

Furthermore, in the photosensitive resin composition of the present invention, the naphthylimide group-containing sulfonic acid compound is contained in an amount of 0.1 part by mass or more per 100 parts by mass of the polymer and the polyamideimide having a branched structure. The content is preferably 0 parts by mass or less. If the content of the naphthylimide group-containing sulfonic acid compound is within the above range, the chemical resistance, heat-resistant shape retention, sensitivity, and resolution of thick films can be further improved for the resulting positive resist film. can.

Furthermore, it is preferable that the photosensitive resin composition of the present invention further contains a photosensitizer and a crosslinking agent. If the photosensitive resin composition further contains a photosensitizer and a crosslinking agent, a positive resist film can be easily formed.

Further, according to the present invention, a lens formed from any of the photosensitive resin compositions described above is provided. Such lenses have excellent transparency and heat-resistant shape retention.

According to the photosensitive resin composition of the present invention, a positive resist film and lens having excellent transparency and heat-resistant shape retention can be formed.

FIG. 1 is a schematic cross-sectional view showing an example of a micro LED including a protective insulating film and a lens formed using a photosensitive resin composition according to an embodiment of the present invention. FIG. 1 is a diagram showing an example of a dot pattern formed using a photosensitive resin composition according to an embodiment of the present invention.

Embodiments of the present invention will be described in detail below.
Here, the photosensitive resin composition of the present invention can be used for, for example, micro LEDs, micro OLEDs, organic EL elements, and protective films for touch panels, electrical insulating films, and passivation films. Moreover, the photosensitive resin composition of the present invention can be used, for example, when forming a resist pattern in the manufacturing process of micro LED arrays and the like.

(Photosensitive resin composition)
The photosensitive resin composition of the present invention contains a predetermined polymer, a polyamideimide having a branched structure, and a naphthylimide group-containing sulfonic acid compound, and optionally a photosensitizer, a crosslinking agent, a solvent, It further contains known additives that can be incorporated into photosensitive resin compositions. In addition to the predetermined polymer, the photosensitive resin composition of the present invention contains polyamideimide having a branched structure and a naphthylimide group-containing sulfonic acid compound, so it has transparency and heat-resistant shape retention. A positive resist film (hereinafter also simply referred to as "resist film") having excellent properties can be formed.

If the resist film has high transparency and heat-resistant shape retention, it is suitable for forming resin films included in various light emitting elements, light receiving elements, etc. using the resist film. If the transparency of the resist film is high, the amount of attenuation of light in the resin film can be reduced when a light emitting element or a light receiving element is formed using such a resist film.
In particular, a resin film provided on a light emitting element may function as a lens. More specifically, in forming a resin film of a light emitting element, a coating film formed using a resin composition is subjected to a patterning process to form a pattern having an angular cross-sectional shape, such as a cylindrical shape. After obtaining a patterned coating film having a dot pattern consisting of a plurality of cylindrical patterns arranged at predetermined intervals, the patterned coating film containing each cylindrical pattern is heated to a fluid state, and the cross-sectional shape of each pattern is changed due to surface tension. A process that can be called a "melt flow process" is sometimes performed to give the melt a smooth shape. A pattern with a gentle cross-sectional shape functions as a so-called "lens" and can exhibit a light condensing function and/or a light diffusing function. Even in such a case, if the resist film has high transparency and heat-resistant shape retention, a resin film that can function as a lens can be formed satisfactorily. In particular, if the heat-resistant shape retention of the resist film is high, the gaps between each pattern in the patterned coating film will be reduced during the melt flow process, the post-bake process when forming a resin film from the coating film, and even wiring etc. Excessive changes can be suppressed by heat treatment that may be performed in the process of forming the peripheral structure or the like. Therefore, dome-shaped (hemispherical) patterns that are spaced apart from each other and are dispersed like "islands" can be favorably formed on the substrate. Therefore, according to the photosensitive resin composition of the present invention which is excellent in transparency and heat-resistant shape retention, it is possible to satisfactorily provide a highly transparent pattern or lens formed at desired intervals.

<Polymer>
Here, the polymer used in the photosensitive resin composition of the present invention has a predetermined monomer unit.

[Monomer unit]
Examples of the predetermined monomer unit include monomer units represented by the following general formula (I), preferably vinylphenol monomer units. Furthermore, the predetermined monomer units may optionally include (meth)acrylate monomer units, aromatic vinyl monomer units (excluding vinylphenol monomer units), and other monomer units. Can be mentioned.
(In the general formula (I), R ¹ is a chemical single bond or a divalent hydrocarbon group having 1 to 6 carbon atoms which may have a substituent, and R ² is a hydrogen atom, or a monovalent hydrocarbon group having 1 to 6 carbon atoms which may have a substituent.)

- Monomer unit represented by general formula (I) -
The monomer unit represented by the general formula (I) is a structural unit represented by the following general formula (I).
In the above general formula (I), R ¹ is a chemical single bond or a divalent hydrocarbon group having 1 to 6 carbon atoms which may have a substituent, and is preferably a chemical single bond or a divalent hydrocarbon group having 1 to 6 carbon atoms, which may have a substituent. A bond or an alkylene group having 1 to 4 carbon atoms (branched or straight chain type), and more preferably a single chemical bond or an alkylene group having 1 to 2 carbon atoms. In the above general formula (I), R ² is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms which may have a substituent, preferably a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms. An alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms.

Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, and bromine atom; alkoxy groups having 1 to 10 carbon atoms such as methoxy group, ethoxy group, and isopropoxy group; nitro group; cyano group; phenyl group; Examples thereof include a phenyl group which may have a substituent such as a 4-methylphenyl group and a 2-chlorophenyl group; a hydroxyl group; and the like.

Examples of the monomer unit represented by the general formula (I) include (i) vinylphenol monomer unit described below, (ii) α-methyl-4-hydroxystyrene, α-methyl-3-hydroxy Examples include monomer units derived from monomers such as styrene, α-methyl-2-hydroxystyrene, 4-hydroxyallylbenzene, 3-hydroxyallylbenzene, and 2-hydroxyallylbenzene. Among these, vinylphenol monomer units described below are preferred.

-Vinylphenol monomer unit-
The vinylphenol monomer unit is a structural unit represented by the following structural formula (I).
Here, the structural unit represented by the above-mentioned structural formula (I) is not only a structural unit derived from a vinylphenol monomer, but also a phenolic unit derived from a vinylphenol monomer, for example, as shown in Synthesis Example 1 described below. It also includes a structural unit obtained by deprotecting a structural unit derived from a compound with a protected hydroxyl group (for example, p-tert-butoxystyrene).
Specific examples of the vinylphenol monomer include 4-hydroxystyrene (p-vinylphenol), 3-hydroxystyrene (m-vinylphenol), and p-isopropenylphenol. Among these, 4-hydroxystyrene (p-vinylphenol) is preferred from the viewpoint of availability and cost.
These vinylphenol monomers and compounds whose phenolic hydroxyl groups are protected with arbitrary protecting groups may be used alone or in combination of two or more.

The content of the structural unit represented by structural formula (I) in the polymer is not particularly limited, but is preferably 30% by mass or more, and preferably 80% by mass or less.
When the content of the structural unit represented by structural formula (I) in the polymer is 30% by mass or more, the solubility in an alkaline developer can be increased. On the other hand, when the content of vinylphenol monomer units in the polymer is 80% by mass or less, the transparency of the resulting resist film can be further improved.

-(meth)acrylate monomer unit-
The (meth)acrylate monomer unit is a structural unit derived from a (meth)acrylate monomer. It is preferable that the polymer is a copolymer further having a (meth)acrylate monomer unit. If the polymer is a copolymer further having a (meth)acrylate monomer unit, the sensitivity of the photosensitive resin composition can be improved, and the transparency of the resist film can be further improved.

The (meth)acrylate monomer is not particularly limited, but includes, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, n-heptyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate, n-decyl methacrylate, etc. (meth)acrylic acid alkyl ester; 2-methoxyethyl acrylate, 3-methoxypropyl acrylate, 3-methoxybutyl acrylate, ethoxymethyl acrylate, 2-methoxyethyl methacrylate, 3-methoxypropyl methacrylate, methacryl (meth)acrylic acid alkoxyalkyl esters such as 3-methoxybutyl acid and ethoxymethyl methacrylate; and the like. Among these, (meth)acrylic acid alkyl esters are preferred, and methyl methacrylate is more preferred, from the viewpoint of increasing the sensitivity and transparency of the resulting resist film.
These (meth)acrylate monomers may be used alone or in combination of two or more.

The content of (meth)acrylate monomer units in the copolymer is not particularly limited, but is preferably 20% by mass or more, and preferably 70% by mass or less.
When the content of the (meth)acrylate monomer unit in the copolymer is 20% by mass or more, the transparency of the resulting resist film can be further improved. On the other hand, when the content of (meth)acrylate monomer units in the copolymer is 70% by mass or less, solubility in an alkaline developer can be increased.

- Aromatic vinyl monomer units (excluding vinyl phenol monomer units) -
The aromatic vinyl monomer unit is a structural unit derived from an aromatic vinyl monomer unit. Examples of aromatic vinyl monomer units include, but are not limited to, styrene, o, m, p-methylstyrene, p-tert-butylstyrene, ethylstyrene, 2,4-dimethylstyrene, α-methylstyrene, etc. can be mentioned. Among these, styrene is preferred from the viewpoint of availability and cost. These aromatic vinyl monomer units may be used alone or in combination of two or more.

The content of aromatic vinyl monomer units in the copolymer is not particularly limited, but is preferably 30% by mass or more, and preferably 80% by mass or less. When the content of the aromatic vinyl monomer unit in the copolymer is 30% by mass or more, the solubility in an alkaline developer can be increased. On the other hand, when the content of the aromatic vinyl monomer unit in the copolymer is 80% by mass or less, the transparency of the resulting resist film can be further improved.

-Other monomer units-
The other monomer units are structural units derived from other monomers copolymerizable with the above-mentioned monomers, and include, for example, N-phenylmaleimide, acrylonitrile, and the like. Other monomers are not particularly limited as long as they do not inhibit the effects of the present invention.

Specific examples of polymers that can be contained in the photosensitive resin composition of the present invention include vinylphenol/methyl methacrylate copolymer, vinylphenol/styrene copolymer, vinylphenol homopolymer, and the like. I can do it. Among these, vinylphenol/methyl methacrylate copolymer is preferred.
In addition, these polymers may be used individually by 1 type, and may use 2 or more types together.

[Properties of polymer]
-Weight average molecular weight-
When the polymer is a vinylphenol/methyl methacrylate copolymer, the weight average molecular weight (Mw) is preferably 12,000 or less, and preferably 8,000 or more. When the weight average molecular weight (Mw) of the vinylphenol/methyl methacrylate copolymer is 12,000 or less, solubility in a solvent can be improved. Further, it is preferable that the weight average molecular weight (Mw) of the vinylphenol/methyl methacrylate copolymer is 8000 or more from the viewpoints of coating film formation, curability after curing, and mechanical strength.
Note that the above values are in terms of polystyrene.

<Polyamideimide with branched structure>
Since the photosensitive resin composition of the present invention contains polyamideimide having a branched structure, it is possible to form a resist film with excellent transparency. Moreover, the polyamideimide having a branched structure used in the photosensitive resin composition of the present invention can improve the solubility and sensitivity of the photosensitive resin composition in a solvent. Furthermore, since the photosensitive resin composition contains polyamideimide having a branched structure, even when a resist film as thick as 10 μm is formed, for example, the exposure dose is not increased excessively and resolution is maintained. Patterning can be performed. That is, when the photosensitive resin composition contains polyamideimide having a branched structure, a resist film with high "thick film resolution" can be formed. A resist film (coating film) with high "resolution in thick film" has excellent lens forming ability when a patterned coating film is obtained and a lens shape is obtained by performing a melt flow process. Furthermore, when the photosensitive resin composition contains both a polymer having a monomer unit represented by the above general formula (I) and a polyamideimide having a branched structure, the resist of the resulting resist film can be improved. Resistance to chemicals such as stripping solution, that is, chemical resistance can be improved.

The polyamide-imide having a branched structure has, for example, a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and has the following structural formula (1). , a compound having one or more of the terminal structures represented by (2) and (3), a compound represented by the following general formula (3), a polyamide-imide resin having a branched structure (manufactured by DIC, Uni Examples include Dick EMG-793), polyamideimide resin having a branched structure (Unidic EMG-1015, manufactured by DIC Corporation), and the like.

...General formula (1)
However, in the general formula (1), R ¹¹ represents an organic group having a cycloaliphatic structure having 6 to 13 carbon atoms.

...General formula (2)
However, in the general formula (2), R ¹² represents an organic group having a cycloaliphatic structure having 6 to 13 carbon atoms, and R ¹³ represents a linear hydrocarbon structure having a number average molecular weight of 700 to 4,500.

...Structural formula (1)

...Structural formula (2)

...Structural formula (3)

...General formula (3)
However, in the general formula (3), n is 2 or more and 200 or less.

The compound represented by the general formula (3) can be obtained by reacting isophorone diisocyanate isocyanurate with trimethic anhydride (see reaction formula (1) below).

...Reaction formula (1)
However, in the reaction formula (1), n is 2 or more and 200 or less.

In the reaction shown in the above reaction formula (1), a polyfunctional polyol containing two or more hydroxyl groups is added as a chain transfer agent to introduce a moiety having a urethane structure into the partial structure of the above general formula (3). Good too. By introducing the moiety having the urethane structure into a partial structure of the general formula (3), the physical properties of the polyamideimide having the branched structure can be controlled. Examples of the site having the urethane structure include a site represented by the following general formula (4).

...General formula (4)
However, in the general formula (4), R ¹⁴ represents an organic group having a cycloaliphatic structure having 6 to 13 carbon atoms, and R ¹⁵ represents a linear hydrocarbon structure having a number average molecular weight of 700 to 4,500.
[Properties of polyamideimide with branched structure]
-Number average molecular weight-
Here, the number average molecular weight (Mn) of the polyamideimide having the branched structure described above is preferably 30,000 or less, and preferably 2,000 or more. If the number average molecular weight (Mn) of the polyamide-imide having a branched structure is 30,000 or less, it is possible to improve the compatibility with a polymer having a vinylphenol monomer unit and to improve the solubility in a solvent. be able to. In addition, if the number average molecular weight (Mn) of the polyamideimide having a branched structure is 2000 or more, the heat-resistant shape retention of the resulting resist film can be further improved, and the positive Ease of forming a mold resist film can be improved. Furthermore, if the number average molecular weight (Mn) of the polyamideimide having a branched structure is 2000 or more, the heat resistance of the resulting resist film and the mechanical strength after curing can be improved. Note that the value of the number average molecular weight (Mn) of polyamideimide can be determined as a polystyrene equivalent amount according to gel permeation chromatography (GPC) method.
Further, the weight average molecular weight (Mw) of the polyamideimide having the branched structure is preferably 100,000 or less, and preferably 3,000 or more. If the weight average molecular weight (Mw) of the polyamide-imide having a branched structure is 100,000 or less, it is possible to further improve the compatibility with a polymer having a vinylphenol monomer unit, and further improve the solubility in a solvent. can be improved. Moreover, if the weight average molecular weight (Mw) of the polyamideimide having a branched structure is 3000 or more, the heat resistance of the resulting resist film and the mechanical strength after curing can be further improved.

The proportion of the polymer in the total (100% by mass) of the polymer and the polyamideimide having a branched structure is preferably 70% by mass or more, more preferably 80% by mass or more. , is preferably 90% by mass or less, more preferably 85% by mass or less. If the proportion of the polymer in the total (100 mass%) of the polymer and the polyamideimide having a branched structure is 70 mass% or more and 90 mass% or less, the resulting resist film has transparency and heat-resistant shape retention. can be further increased, and at the same time, it is possible to prevent the residual film rate after development and sensitivity from decreasing.

<Naphthylimide group-containing sulfonic acid compound>
A naphthylimide group-containing sulfonic acid compound is a compound that decomposes to produce sulfonic acid when irradiated with radiation. Since the photosensitive resin composition of the present invention contains a naphthylimide group-containing sulfonic acid compound, it has excellent heat-resistant shape retention. Furthermore, the naphthylimide group-containing sulfonic acid compound can improve the sensitivity, chemical resistance, and resolution of a thick film of a resist film obtained using the photosensitive resin composition.

Here, the radiation is not particularly limited, and includes, for example, visible light; ultraviolet rays; Laser beams; particle beams such as electron beams; and the like. Note that these radiations can be used alone or in combination of two or more.

The naphthylimide group-containing sulfonic acid compound is not particularly limited, and examples thereof include 1,8-naphthalimidyl triflate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-105"), 1,8- Naphthalimidyl butane sulfonate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-1004"), 1,8-naphthalimidyl tosylate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-101"), 1,8-naphthalyl Midyl nonafluorobutane sulfonate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-109"), 1,8-naphthalimidyl 9-camphorsulfonate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-106"), 1,8-naphthalene Lumidylethanesulfonate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-1002") and 1,8-naphthalimidylpropane sulfonate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-1003") etc. can be used. can. Among them, from the viewpoint of solubility in solvents, chemical resistance, etc., 1,8-naphthalimidyl triflate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-105") is a naphthylimide group-containing sulfonic acid compound. is preferred.
The content of the naphthylimide group-containing sulfonic acid compound is preferably 0.1 parts by mass or more, and preferably 0.3 parts by mass or more, per 100 parts by mass of the polymer and the polyamideimide having a branched structure. More preferably, it is 2.0 parts by mass or less, and more preferably 1.0 parts by mass or less. When the content of the naphthylimide group-containing sulfonic acid compound is within the above range, the heat-resistant shape retention of the resulting resist film can be sufficiently improved. In particular, by setting the content of the naphthylimide group-containing sulfonic acid compound to the above lower limit or more, the heat-resistant shape retention and chemical resistance of the resulting resist film can be improved. In addition, in particular, by controlling the content of the naphthylimide group-containing sulfonic acid compound to the above upper limit or less, it is possible to improve the resolution of the resulting thick resist film and the storage stability of the photosensitive resin composition. can. Furthermore, by controlling the content of the naphthylimide group-containing sulfonic acid compound within the above range, the sensitivity of the resulting resist film can be increased. Note that the naphthylimide group-containing sulfonic acid compound can be used alone or in a mixture of two or more.

<Photosensitizer>
A photosensitizer is a compound that can cause a chemical reaction when exposed to radiation. As the photosensitizer, compounds capable of controlling the alkali solubility of the resist film formed from the photosensitive resin composition, other than the above-mentioned naphthylimide group-containing sulfonic acid compounds, can be used. In particular, as the photosensitizer, it is preferable to use a compound that decomposes to produce a carboxylic acid when irradiated with radiation. When the photosensitive resin composition further contains a photosensitizer, the ease of forming a resist film can be improved.
Here, as the photosensitizer used in the photosensitive resin composition of the present invention, for example, 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene Ester of bisphenol and 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid, 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1- Ester of methylethyl]phenyl]ethylidene bisphenol (compound represented by the following structural formula (4)) and 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid, 1,1, Ester of 1-tris(4-hydroxyphenyl)ethane (compound represented by the following structural formula (5)) and 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid, 2 -(4-hydroxyphenyl)-2-(2',3',4'-trihydroxyphenyl)propane and ester of 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid , a known compound described as "radiation-sensitive compound (B)" in JP-A No. 2014-29766, and the like. Among these, 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene bisphenol and 6-diazo-5,6-dihydro-5-oxo-naphthalene -Ester with 1-sulfonic acid, and ester with 1,1,1-tris(4-hydroxyphenyl)ethane and 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid is preferred.
These photosensitizers may be used alone or in combination of two or more.

...Structural formula (4)

...Structural formula (5)

Note that the content of the photosensitizer is preferably less than 30 parts by mass, for example, per 100 parts by mass of the total of the polymer and the polyamideimide having a branched structure. If the content of the photosensitizer is less than 30 parts by mass, the sensitivity of the resulting resist film and the resolution in thick films will be further improved, and bubbles will occur in the coating film during exposure of the resist film in the bleaching process etc. can be effectively suppressed. In particular, when using a compound that decomposes to produce carboxylic acid when irradiated with radiation, such as the various esters mentioned above, as a photosensitizer, it is necessary to dissolve the polymer containing the vinylphenol monomer unit in the solvent. The solubility of carboxylic acids in solvents tends to be higher than their properties. In the development step, the carboxylic acid dissolves preferentially in the solvent, and the solubility of the polymer may become insufficient. Therefore, by controlling the content of the photosensitizer to be less than the above upper limit, the sensitivity of the resist film and the resolution in thick films can be further improved.

<Crosslinking agent>
Here, examples of the crosslinking agent used in the photosensitive resin composition of the present invention include polybutanetetracarboxylic acid tetra(3,4-epoxycyclohexylmethyl)-modified ε-caprolactone (manufactured by Daicel Corporation, Epolead GT401) and the like. Functional epoxy compounds, methylol-based compounds such as melamine/formaldehyde/alkyl monoalcohol polycondensate (manufactured by Sanwa Chemical Co., Ltd., Nikalac Mw-100LM), triglycidyl compounds such as triglycidyl isocyanurate (manufactured by Nissan Chemical Co., Ltd., TEPIC-VL) Isocyanurate compounds, alicyclic epoxy resins such as 3,4-epoxycyclohexylmethyl (3,4-epoxy)cyclohexanecarboxylate (manufactured by Daicel, Celloxide 2021P), )" and the like. Among these, polyfunctional ε-caprolactone modified with tetra(3,4-epoxycyclohexylmethyl) butanetetracarboxylate (manufactured by Daicel, Epolead GT401) is used from the viewpoint of flexibility of the film after curing and chemical resistance. Preferably, epoxy compounds are used.
These crosslinking agents may be used alone or in combination of two or more.
In particular, by using a methylol compound in combination with a polyfunctional epoxy compound, the chemical resistance of the resulting resist film can be improved. In particular, by using triglycidyl isocyanurate and/or alicyclic epoxy resin in combination with a polyfunctional epoxy compound, it is possible to maintain the heat-resistant shape retention of the resulting resist film while improving resolution in thick films. Sensitivity can be further improved.
Note that the content of the crosslinking agent can be within a general range.

<Solvent>
Here, as the solvent used in the photosensitive resin composition of the present invention, ether solvents, amide solvents, and mixtures thereof are usually used. Examples of the ether solvent include diethylene glycol ethyl methyl ether (Hysolve EDM, manufactured by Toho Chemical Industry Co., Ltd.), propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyl lactone. Examples of the amide solvent include 1-methyl-2-pyrrolidone, N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA).
As described above, the solvent may be a mixture, but from the viewpoint of ease of recovery and reuse of the solvent, it is preferable to use a single solvent made of a single substance.

<Additives>
Here, examples of additives used in the photosensitive resin composition of the present invention include solubility promoters, anti-aging agents, silane coupling agents, surfactants, ultraviolet absorbers, dyes, and sensitizers. Can be mentioned. These additives may be used singly or in combinations of two or more in general blending amounts depending on desired attributes.

[Solubility promoter]
Examples of the solubility promoter include 5,5'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]bis[2-hydroxy-1,3-benzenedimethanol] (Honshu Chemical Co., Ltd.). TML-BPAF-MF (manufactured by Kogyo Co., Ltd.), 3,3',5,5'-tetramethoxymethyl-4,4'-bisphenol (manufactured by Honshu Kagaku Kogyo Co., Ltd., TMOM-BP), and other known dissolution promoters. agents, etc. Among these, 5,5'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]bis[2-hydroxy-1, 3-benzenedimethanol] (manufactured by Honshu Kagaku Kogyo Co., Ltd., TML-BPAF-MF) is preferably used.
These solubility promoters may be used alone or in combination of two or more.

[Anti-aging agent]
As the anti-aging agent, for example, pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (a compound represented by the following structural formula (6), manufactured by BASF) , Irganox 1010), 2,4-bis[(dodecylthio)methyl]-6-methylphenol (compound represented by the following structural formula (7), manufactured by BASF, Irganox 1726), etc. Examples include sulfur-based anti-aging agents and other known anti-aging agents. Among these, from the viewpoint of transparency, pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF, Irganox 1010) is preferred.
These anti-aging agents may be used alone or in combination of two or more.

... Structural formula (6)

... Structural formula (7)

[Silane coupling agent]
The silane coupling agent is not particularly limited, and any known one can be used (for example, see JP-A No. 2015-94910). Among these, 3-(phenylamino ) Propyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-573) and glycidoxypropyltrimethoxysilane (manufactured by XIAMETER, OFS-6040) are preferred. These silane coupling agents may be used alone or in combination of two or more.

[Surfactant]
Examples of the surfactant include organosiloxane polymer (manufactured by Shin-Etsu Chemical Co., Ltd., KP341) and other known surfactants. Among these, organosiloxane polymers are preferred from the viewpoint of coatability on substrates.
These surfactants may be used alone or in combination of two or more.

<Method for manufacturing photosensitive resin composition>
The photosensitive resin composition of the present invention can be prepared by mixing the above-mentioned components by a known method and optionally filtering the mixture. Here, for mixing, known mixers such as a stirrer, ball mill, sand mill, bead mill, pigment dispersion machine, crusher, ultrasonic dispersion machine, homogenizer, planetary mixer, Filmix, etc. can be used. Further, for filtering the mixture, a general filtration method using a filter medium such as a filter can be adopted.

<Method for forming coating film and (lenticular) resin film>
The resin film using the photosensitive resin composition of the present invention is not particularly limited, and for example, after forming a coating film using the photosensitive resin composition of the present invention on a substrate on which the resin film is to be formed. , can be formed by irradiating a coating film with radiation and further heating the coating film after irradiation with radiation. Note that the coating film provided on the substrate may be patterned. Furthermore, the coating film may be subjected to a bleaching process, if necessary.
Furthermore, the arrangement of the coating film on the substrate on which the resin film is formed is not particularly limited, and after forming the coating film on the substrate using a coating method, film lamination method, etc. This can be done by patterning the film.

[Formation of coating film]
Here, the coating film can be formed by the coating method by coating the photosensitive resin composition on the substrate and then drying it by heating (prebaking). The photosensitive resin composition may be applied by various methods such as spray coating, spin coating, roll coating, die coating, doctor blade coating, bar coating, screen printing, and inkjet coating. can be adopted. The heating and drying conditions vary depending on the type and blending ratio of the components contained in the photosensitive resin composition, but the heating temperature is usually 30 to 150°C, preferably 60 to 130°C, and the heating time is , usually for 0.5 to 90 minutes, preferably 1 to 60 minutes, more preferably 1 to 30 minutes.

In addition, the formation of a coating film by the film lamination method involves applying a photosensitive resin composition onto a base material for forming a B-stage film such as a resin film or a metal film, and then heating and drying it (pre-baking process) to form a B-stage film. After obtaining the B-stage film, the B-stage film is then laminated on the substrate. Note that the application of the photosensitive resin composition onto the substrate for forming a B-stage film and the heating and drying of the photosensitive resin composition are performed in the same manner as the application and heating and drying of the photosensitive resin composition in the coating method described above. be able to. Moreover, lamination can be performed using a pressure bonding machine such as a pressure laminator, a press, a vacuum laminator, a vacuum press, a roll laminator, or the like.

An arbitrary patterning process that can be performed on a coating film provided on a substrate includes, for example, irradiating the coating film before patterning with radiation as described above to form a latent image pattern, and then forming a latent image pattern. This can be carried out using a known patterning method such as a photolithography method in which a developer is brought into contact with a coating film having a pattern to make the pattern visible.

Furthermore, as a method of forming a latent image pattern by irradiating radiation in a pattern, a known method such as a method of using a reduction projection exposure apparatus and irradiating radiation through a desired mask pattern can be used. .
The radiation irradiation conditions are appropriately selected depending on the radiation used, but for example, the wavelength of the radiation can be within the range of 365 nm or more and 436 nm or less, and the irradiation amount is, for example, 900 mJ/cm ² or less. It can be done.

Further, the developer is not particularly limited, and a known alkaline developer such as a 2.38% by mass aqueous tetramethylammonium hydroxide solution can be used. The method of bringing the developer into contact with the coating film and the development conditions are not particularly limited and can be appropriately set so as to obtain a resist pattern of desired quality. Note that the development time can be determined as appropriate using the method for determining the development conditions described above.

Note that the patterned coating film obtained as described above can be rinsed with a rinsing liquid, if necessary, in order to remove development residues. After the rinsing process, the remaining rinsing liquid may be further removed using compressed air or compressed nitrogen.

After obtaining a patterned coating film using the method described above, the patterned coating film is subjected to a melt flow process to change the cross-sectional shape of each pattern included in the patterned coating film into a gentle shape. A patterned coating may also be obtained. By this change, for example, a pattern with an angular cross-sectional shape is changed into a pattern with a gentle shape without corners. Specifically, for example, when a dot pattern is formed on a patterned coating film, this patterned coating film is subjected to a melt flow process in which the patterned coating film is held at a predetermined temperature range for a predetermined period of time to transform the pattern into a cylindrical or approximately circular shape. By changing the shape from a columnar dot shape to a hemispherical shape, a lens pattern with a diameter of about 2 to 20 μm can be formed. Note that the heating method in the melt flow step is not particularly limited, and examples thereof include heating on a hot plate or in an oven. Further, the heating temperature in the melt flow step is any temperature higher than the melting point of the coating film, for example, 100 to 170°C, preferably 120 to 150°C, and the heating time is usually 2 to 15 minutes, preferably is 5 to 10 minutes.

Further, optionally, the coating film subjected to the patterning process may be subjected to a bleaching process prior to the melt flow process. In the bleaching process, the coating film is irradiated with the radiation described above to decompose the naphthylimide group-containing sulfonic acid compound and generate sulfonic acid, thereby increasing the chemical resistance and transparency of the coating film. be able to. The radiation irradiation conditions are appropriately selected depending on the radiation used, but for example, the wavelength of the radiation can be within the range of 365 nm or more and 436 nm or less, and the irradiation amount is, for example, 750 mJ/cm ² As described above, the irradiation amount can be larger than that in the patterning step.

[Formation of (lenticular) resin film]
A lens-shaped resin film (that is, a lens made of the photosensitive resin composition of the present invention) can be formed by heating (post-baking) and curing the coating film obtained as described above.

Heating of the coating film in the post-baking step is not particularly limited, and can be performed using, for example, a hot plate, an oven, or the like. Note that heating may be performed under an inert gas atmosphere if necessary. Examples of the inert gas include nitrogen, argon, helium, neon, xenon, and krypton. Among these, nitrogen and argon are preferred, with nitrogen being particularly preferred.

Here, the temperature at which the coating film is heated can be, for example, 100 to 300°C. The time for heating the coating film can be appropriately selected depending on the area and thickness of the coating film, the equipment used, etc., and can be, for example, 10 to 60 minutes.

(Micro LED)
FIG. 1 is a schematic cross-sectional view showing an example of a micro LED including a protective insulating film and a lens formed using a photosensitive resin composition according to an embodiment of the present invention.
In FIG. 1, the micro LED 10 includes an epitaxial wafer 20, a plurality of n-dot electrodes 30 formed on one main surface of the epitaxial wafer 20, and a p-pad electrode 40 formed on the other main surface of the epitaxial wafer 20. Prepare for this. Furthermore, the micro LED 10 includes a protective insulating film 50 on the main surface on the side where the p-pad electrode 40 is formed, and a lens 60 formed on the protective insulating film 50.

For example, a micro LED having the above structure can be manufactured using the photosensitive resin composition of the present invention as follows. First, a resin film corresponding to the protective insulating film 50 is obtained by performing coating, a pre-bake process, a post-bake process, etc. using the photosensitive resin composition of the present invention having a predetermined composition. Then, on the obtained protective insulating film 50, the photosensitive resin composition of the present invention having the same or different composition as the photosensitive resin composition used when forming the protective insulating film 50 is applied, A resin film corresponding to the lens 60 is obtained by performing a pre-bake process, a patterning process, a melt flow process, a post-bake process, and the like. Note that the formation locations of the protective insulating film 50 and the lens 60 can be arbitrarily determined as necessary. The patterning process that can be performed when forming the lens 60 using the photosensitive resin composition of the present invention can be performed according to the known photolithography method as described above, so that high pattern accuracy can be obtained. It is easy to form the lens 60 into a fine structure.

Note that when manufacturing micro-LEDs having the structure shown in FIG. 1, normally, instead of manufacturing only one micro-LED having such a structure, an array sheet in which a plurality of micro-LEDs are arranged on a wafer is manufactured. After the array sheet is obtained, one micro LED as shown in FIG. 1 is generally obtained by dicing the array sheet. Therefore, when forming a lens by obtaining a patterned coating film, dot patterns corresponding to each of the plurality of micro LEDs included in the array sheet are formed in the patterning process, and then the melt flow process is performed. The shape of each pattern is changed into a lens shape.

The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples. "Parts" in each example are based on mass unless otherwise specified.

Examples of the preparation of (co)polymers are shown below in Synthesis Examples 1 and 2.
(Synthesis example 1)
<Preparation of copolymer (A-1) having p-vinylphenol monomer units and methyl methacrylate monomer units>
50 parts of p-tert-butoxystyrene as a compound whose phenolic hydroxyl group is protected by a protecting group, 50 parts of methyl methacrylate as a (meth)acrylate monomer, and azobisisobutyronitrile as a polymerization initiator. 4 parts were dissolved in 150 parts of propylene glycol monomethyl ether as a solvent, and the reaction temperature was maintained at 70° C. under a nitrogen atmosphere to polymerize for 10 hours. Then, sulfuric acid was added to the reaction solution and the reaction temperature was maintained at 90°C for 10 hours to deprotect the p-tert-butoxystyrene monomer unit and convert it into a p-vinylphenol monomer unit. . Then, ethyl acetate is added to the obtained copolymer, water washing is repeated five times, the ethyl acetate phase is separated, and the solvent is removed to form p-vinylphenol monomer units and methyl methacrylate monomer units. A copolymer (A-1) having the unit was obtained. The ratio of each monomer unit in the obtained copolymer (A-1) was p-vinylphenol monomer unit: methyl methacrylate monomer unit = 50:50 (mass ratio). The weight average molecular weight (Mw) was 9,600 in terms of polystyrene.

(Synthesis example 2)
<Preparation of cyclic olefin polymer (A-2)>
40 mol% N-phenyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide (NBPI), and 4-hydroxycarbonyltetracyclo[6.2.1.13,6. 02,7] Dodec-9-ene (TCDC) 60 mol% monomer mixture 100 parts, 1,5-hexadiene 2.0 parts, (1,3-dimesitylimidazolin-2-ylidene) (tri- Cyclohexylphosphine) 0.02 part of benzylidene ruthenium dichloride (synthesized by the method described in Org. Lett., Vol. 1, p. 953, 1999) and 200 parts of diethylene glycol ethyl methyl ether were replaced with nitrogen. The mixture was charged into a reactor and reacted at 80° C. for 4 hours with stirring to obtain a polymerization reaction solution. The obtained polymerization reaction solution was placed in an autoclave and stirred for 5 hours at 150° C. and a hydrogen pressure of 4 MPa to perform a hydrogenation reaction, resulting in a cyclic olefin polymer (A-2) containing a carboxyl group as an acidic group. A polymer solution was obtained. The polymerization conversion rate of the obtained cyclic olefin polymer (A-2) was 99.7%, and the weight average molecular weight (Mw) was 7150 in terms of polystyrene.

(Example 1)
(i) 85 parts of copolymer (A-1) having p-vinylphenol monomer units and methyl methacrylate monomer units obtained in Synthesis Example 1 as a polymer, (ii) branched structure polyamide-imide resin (manufactured by DIC Corporation, Unidic EMG-793, solid content 43.7% (solvent is propylene glycol monomethyl ether acetate), acid value 65.6 mg (KOH)/g, viscosity (25°C, E type) Viscometer) 1.04 Pa s, number average molecular weight (polystyrene equivalent amount according to gel permeation chromatography (GPC) method) 2000 or more and 30000 or less) 15 parts, (iii) as a naphthylimide group-containing sulfonic acid compound, 1 , 0.5 part of 8-naphthalimidyl triflate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-105"), (iv) 4,4'-[1-[ as a photosensitizer (radiation-sensitive compound)) Ester of 4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene bisphenol and 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid (2.5 molar form) (manufactured by Bigen Shoji Co., Ltd., TPA-525) 10 parts, and 1,1,1-tris(4-hydroxyphenyl)ethane and 6-diazo-5,6-dihydro-5-oxo-naphthalene-1 - 10 parts of an ester with sulfonic acid (2 moles) (manufactured by Toyo Gosei Co., Ltd., HP-200), (v) butanetetracarboxylic acid tetra(3,4-epoxycyclohexylmethyl) modified ε-caprolactone as a crosslinking agent (manufactured by Daicel Corporation, Epolead GT401) 40 parts, and melamine formaldehyde alkyl monoalcohol polycondensate (manufactured by Sanwa Chemical Co., Ltd., Nikalak Mw-100LM) 10 parts, (vi) 5,5'- 10 parts of [2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]bis[2-hydroxy-1,3-benzenedimethanol] (manufactured by Honshu Kagaku Kogyo Co., Ltd., TML-BPAF-MF), ( vii) As an anti-aging agent (antioxidant), 2.5 parts of pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF, Irganox 1010), ( viii) As a silane coupling agent, 3 parts of 3-(phenylamino)propyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBM-573") and glycidoxypropyltrimethoxysilane (manufactured by XIAMETER, OFS) -6040) 3 parts, (ix) organosiloxane polymer (manufactured by Shin-Etsu Chemical Co., Ltd., KP341) 300 ppm (based on the total mass of the mixture before filtration) as a surfactant, and (x) diethylene glycol ethyl methyl ether (as a solvent) A photosensitive resin composition was prepared by mixing and dissolving 100 parts of Hysolve EDM (manufactured by Toho Chemical Industry Co., Ltd.) and filtering through a polytetrafluoroethylene filter with a pore size of 0.45 μm. The prepared photosensitive resin composition was subjected to the following evaluations (exposure sensitivity, thick film resolution, development residual film rate, light transmittance, chemical resistance, heat resistant shape retention, bubbles during exposure). Ta. The results are shown in Table 1.

<Exposure sensitivity>
A photosensitive resin composition was applied onto a silicon wafer substrate by a spin coating method, and dried (prebaked) by heating at 120° C. for 2 minutes using a hot plate to form a coating film with a thickness of 10 μm. Next, in order to pattern the coating film in the patterning step, a mask capable of forming a dot pattern with a diameter of 20 μm and a distance between dots of 10 μm as shown in FIG. Irradiate with h-i mixed radiation (wavelength: i-line = 365 nm, h-line = 405 nm, g-line = 436 nm) so that the exposure amount is different in the range of 500 mJ/cm ² to 1300 mJ/cm ² . carried out the process. Next, development was performed at 25°C for 90 seconds using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide, and by rinsing with ultrapure water for 20 seconds, multiple parts obtained at different exposure doses were developed. A laminate consisting of a coating film having an extending dot pattern and a silicon wafer substrate was obtained.
The dot pattern formed portion of the obtained laminate was observed using an optical microscope, and the diameter of the dot pattern included in the portion exposed at each exposure amount was measured. Then, an approximate curve is created from the relationship between each exposure amount and the diameter of the dot pattern formed at the corresponding exposure amount, the exposure amount when the diameter of the dot pattern is 20 μm is calculated, and the exposure amount is calculated as the exposure sensitivity ( (also simply referred to as "sensitivity"). The lower the exposure amount when the diameter of the dot pattern is 20 μm, the higher the exposure sensitivity because the pattern can be formed with lower energy or in a shorter time.

<Resolution with thick film>
In the patterning process, the process was carried out in the same manner as in the measurement of <exposure sensitivity> described above, except that the g-h-i mixed line was irradiated with an exposure amount corresponding to the exposure sensitivity obtained by measuring <exposure sensitivity>. A laminate consisting of a coating film having a dot pattern and a silicon wafer was obtained. The dot pattern forming area and the area between the dot patterns of the obtained laminate were observed using an optical microscope, and the resolution was evaluated according to the following evaluation criteria. Note that since the film thickness of 10 μm is a relatively thick film, the evaluation results indicate the resolution with a “thick film”.
〔Evaluation criteria〕
A: The pattern can be resolved with an exposure amount of less than 800 mJ/cm ² , and no skirting or residue is observed in the dot pattern forming area and the area between the dot patterns.
B: The pattern can be resolved with an exposure amount of 800 mJ/cm ² or more and less than 1000 mJ/cm ² , and no trailing or residue is observed in the dot pattern forming area and the area between the dot patterns.
C: The pattern can be resolved with an exposure amount of less than 1000 mJ/cm ² , but trailing and residue are observed in the dot pattern formation area and the area between the dot patterns.
D: The pattern cannot be resolved when the exposure amount is less than 1000 mJ/cm ² .

<Development residual film rate>
A coating film with a thickness of 10 μm was formed on a silicon wafer substrate in the same manner as in the measurement of <exposure sensitivity> described above. Next, a process simulating the "development process" in the case of a patterning process, in which immersion in a 2.38 mass % tetramethylammonium hydroxide aqueous solution at 25°C for 90 seconds, was performed, and then the process was performed with ultrapure water. By rinsing for 20 seconds, a laminate consisting of the coating film and the silicon wafer was obtained. The film thickness of the obtained coating film was measured using an optical interference type film thickness measuring device (Lambda Ace VM-1200, manufactured by SCREEN Semiconductor Solutions Co., Ltd.), and the residual film thickness was determined from the film thickness after development process/film thickness before development process. The film rate (%) was calculated. It is preferable that the residual film rate after development is high because the amount of varnish loss and unevenness during development can be reduced.

<Light transmittance (heat resistance transparency)>
A photosensitive resin composition was applied onto a glass substrate (Corning 1737, manufactured by Corning Incorporated) by spin coating, and heated and dried (prebaked) at 120°C for 2 minutes using a hot plate to form a coating film with a thickness of 10 μm. Formed. Next, the coating film was immersed in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide at 25°C for 90 seconds, simulating the "development process" used in the patterning process, and then soaked in ultrapure water. and rinsed for 20 seconds. Next, a laminate consisting of a resin film and a glass substrate was obtained by performing post-baking in an oxidizing atmosphere of heating at 200° C. for 60 minutes in an air atmosphere using an oven.
The obtained laminate was measured at a wavelength of 400 nm to 800 nm using a spectrophotometer V-560 (manufactured by JASCO Corporation). From the measurement results, the average light transmittance (%) at 400 to 800 nm was calculated, which was calculated as heat-resistant transparency. Note that the light transmittance (%) of the resin film was calculated using a converted value assuming that the thickness of the resin film was 10 μm using a blank glass substrate with no resin film attached.
The higher the light transmittance (heat-resistant transparency), the lower the amount of light attenuation by the resin film. Furthermore, the higher the light transmittance of a resin film, the higher the brightness of reflected light that occurs when a laminate of such a resin film and a glass substrate or the like is irradiated with light tends to become higher. A laminate with high reflected light brightness has a beautiful laminate appearance and can be suitably used in various applications.

<Chemical resistance>
A coating film with a thickness of 10 μm was formed on a silicon wafer substrate in the same manner as in the measurement of <exposure sensitivity> described above. Next, a process simulating the "development process" in the case of a patterning process, in which immersion in a 2.38 mass % tetramethylammonium hydroxide aqueous solution at 25°C for 90 seconds, was performed, and then the process was performed with ultrapure water. Rinsing was performed for 20 seconds. Next, post-baking was performed in an oxidizing atmosphere by heating at 130° C. or 150° C. for 60 minutes in an air atmosphere to obtain a laminate consisting of a resin film and a silicon wafer substrate.
The obtained laminate was immersed for 15 minutes in 200 mL of NMP (N-methyl-2-pyrrolidone), a resist stripping solution, which was maintained at 80° C. in a constant temperature bath. The thickness of the resin film before and after immersion was measured using an optical interference film thickness measuring device (Lambda Ace VM-1200, manufactured by SCREEN Semiconductor Solutions Co., Ltd.), and the formula: [Thickness of the resin film after immersion (T _BI )] / film thickness of the resin film before immersion ( _TAI ) x 100], calculate the ratio of the film thickness after immersion to the film thickness before immersion (T _BI / _TAI ) [%], and calculate this ratio. By subtracting from 100%, the film thickness change rate [%] of the resin film was calculated, and the chemical resistance was evaluated according to the following evaluation criteria. Note that even when post-baked at a relatively low temperature such as 150°C and 130°C, a photosensitive resin composition that has a low rate of change in film thickness with respect to a resist stripping solution has a lower rate of change than a material with low heat resistance. The substrate shown in FIG. 1 is also preferable because it can be used as a substrate.
〔Evaluation criteria〕
A: The rate of change in the thickness of the resin film is within ±10% both when post-baking at 130°C and when post-baking at 150°C B: The rate of change in the thickness of the resin film is only when post-baking at 150°C Within ±10% C: The film thickness change rate of the resin film is more than +10% or less than -10% in both cases of post-baking at 130°C and post-baking at 150°C.

<Heat-resistant shape retention>
A coating film with a thickness of 10 μm was formed on a silicon wafer substrate in the same manner as in the measurement of <exposure sensitivity> described above. This coating film was exposed to light in the patterning step using the same mask as in the measurement of <exposure sensitivity> at an exposure amount corresponding to the exposure sensitivity obtained in the measurement of <exposure sensitivity>. Next, a 2.38% by mass aqueous tetramethylammonium hydroxide solution was used for development at 25°C for 90 seconds, followed by rinsing with ultrapure water for 20 seconds to form a positive 20 μm dot patterned coating. Formed.
Then, the cross-sectional shape of the obtained patterned coating film was observed using a scanning electron microscope (SEM), and the width a between the dot patterns was measured based on the SEM image (magnification: 10,000 times). Next, a bleaching process was carried out in which the entire surface of the patterned resin film was irradiated with g-hi mixed radiation at a dose of 2000 mJ/cm ² . Next, the substrate on which this pattern was formed was heat-treated at 120° C. for 10 minutes using a hot plate to perform a melt flow process. In the melt flow process, the patterned coating film was melted to change the pattern from a substantially cylindrical shape to a hemispherical shape (lens shape). Furthermore, by performing a post-bake process by heating the substrate that has undergone the melt flow process at 200°C for 30 minutes using a hot plate, it has a pattern that is a hemispherical part (lens) with a thickness of 10 μm at the apex. A resin film was formed. Then, the cross-sectional shape of the pattern obtained through the post-baking step was observed using a SEM in the same manner as above, and the width b between the patterns was measured based on the SEM image. Using the obtained measurement results, determine the difference (a-b) between the width a between the dot patterns after forming the patterned coating film and the width b between the patterns after the post-baking process, and pattern it according to the following evaluation criteria. The lens shape (heat-resistant shape retention) of the resin film was evaluated. Note that the value of the difference (ab) was calculated for 10 locations, and the numerical average value of the values at 10 locations was used for evaluation.
〔Evaluation criteria〕
A: The pattern has a hemispherical shape, and the difference (ab) value is 2 μm or less.
B: The pattern has a hemispherical shape, and the value of the difference (ab) is more than 2 μm and 4 μm or less.
C: The value of the difference (ab) exceeds 4 μm, or the pattern is completely melted in the post-baking process and fused to the adjacent pattern.

<Bubble during exposure>
A coating film with a thickness of 10 μm was formed on a silicon wafer substrate in the same manner as in the measurement of <exposure sensitivity> described above. Next, a bleaching process is performed in which the entire surface of the coating film is irradiated with g-hi mixed radiation at a dose of 2000 mJ/cm ² , and a laminate having a bleached coating film on a silicon wafer substrate is produced. I got it. Then, the laminate was heated at 200° C. for 30 minutes using a hot plate to perform a post-baking process. The laminate that had undergone the post-baking process was observed using an optical microscope to confirm the presence or absence of bubbles within the laminate. Those in which no bubbles were observed were evaluated as "A," and those in which bubbles were observed were evaluated as "B."

(Example 2)
Same as Example 1 except that the blending amounts of copolymer (A-1) and polyamide-imide resin having a branched structure (manufactured by DIC Corporation, Unidic EMG-793) were changed as shown in Table 1. A photosensitive resin composition was prepared, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Example 3)
In Example 1, instead of using 10 parts of (v) melamine formaldehyde alkyl monoalcohol polycondensate (Nicalac Mw-100LM, manufactured by Sanwa Chemical Co., Ltd.) as a crosslinking agent, (v) triglycidyl isocyanurate (Nissan A photosensitive resin composition was prepared in the same manner as in Example 1, except that 10 parts of TEPIC-VL (manufactured by Kagaku Co., Ltd.) was used, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Example 4)
In Example 1, instead of using 10 parts of (v) melamine formaldehyde alkyl monoalcohol polycondensate (manufactured by Sanwa Chemical Co., Ltd., Nikalac Mw-100LM) as a crosslinking agent, (v) 3,4-epoxycyclohexyl was used. A photosensitive resin composition was prepared in the same manner as in Example 1, except that 10 parts of methyl (3,4-epoxy)cyclohexane carboxylate (manufactured by Daicel, Celoxide 2021P) was used, and the prepared photosensitive resin Each evaluation was performed using the composition. The results are shown in Table 1.

(Example 5)
In Example 1, the amount of (iii) 1,8-naphthalimidyl triflate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-105") as a naphthylimide group-containing sulfonic acid compound was 0.5 part. A photosensitive resin composition was prepared in the same manner as in Example 1, except that the amount was changed from 1.0 parts to 1.0 part, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Example 6)
In Example 1, the amount of (iii) 1,8-naphthalimidyl triflate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-105") as a naphthylimide group-containing sulfonic acid compound was 0.5 part. A photosensitive resin composition was prepared in the same manner as in Example 1, except that the amount was changed from 3.0 parts to 3.0 parts, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Comparative example 1)
In Example 1, except that (iii) 1,8-naphthalimidyl triflate (manufactured by Midori Kagaku Co., Ltd., product name "NAI-105") was not blended as a naphthylimide group-containing sulfonic acid compound. A photosensitive resin composition was prepared in the same manner as in Example 1, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Comparative example 2)
In Comparative Example 1, sensitization was carried out in the same manner as in Comparative Example 1, except that (v) 10 parts of melamine/formaldehyde/alkyl monoalcohol polycondensate (manufactured by Sanwa Chemical Co., Ltd., Nikalak Mw-100LM) was not blended. A photosensitive resin composition was prepared, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Comparative example 3)
In Comparative Example 2, (iv) 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene bisphenol and 6-diazo-5,6 -Ester form (2.5 molar form) with dihydro-5-oxo-naphthalene-1-sulfonic acid (manufactured by Bigen Shoji Co., Ltd., TPA-525), and 1,1,1-tris(4-hydroxyphenyl) The amount of the ester (2 moles) of ethane and 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid (manufactured by Toyo Gosei Co., Ltd., HP-200) was varied from 10 to 12 parts, respectively. .5 parts, and the amount of (v) epoxidized butanetetracarboxylic acid tetrakis(3-cyclohexenylmethyl) modified ε-caprolactone (manufactured by Daicel Corporation, Epoliad GT401) as a crosslinking agent was changed from 40 parts to 33 parts. A photosensitive resin composition was prepared in the same manner as in Comparative Example 2 except for the changes, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Comparative example 4)
In Comparative Example 3, (iv) 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene bisphenol and 6-diazo-5,6 -Ester form (2.5 molar form) with dihydro-5-oxo-naphthalene-1-sulfonic acid (manufactured by Bigen Shoji Co., Ltd., TPA-525), and 1,1,1-tris(4-hydroxyphenyl) 12.5 parts of each ester of ethane and 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid (2 moles) (manufactured by Toyo Gosei Co., Ltd., HP-200) was added. A photosensitive resin composition was prepared in the same manner as in Comparative Example 3, except that the amount was changed from 15 parts to 15 parts, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Comparative example 5)
In Example 1, as (i) the polymer, 100 parts of the cyclic olefin polymer (A-2) obtained in Synthesis Example 2 was substituted for the copolymer (A-1) obtained in Synthesis Example 1. (iv) 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene bisphenol and 6-diazo-5,6-dihydro The amount of the ester with -5-oxo-naphthalene-1-sulfonic acid (2.5 moles) (manufactured by Bigen Shoji Co., Ltd., TPA-525) was changed from 10 parts to 36.3 parts, and the same amount of photosensitive (iv) ester form (2 molar form) with 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid (manufactured by Toyo Gosei Co., Ltd., HP-200) is not blended, Furthermore, the amount of (v) epoxidized butanetetracarboxylic acid tetrakis(3-cyclohexenylmethyl)-modified ε-caprolactone (manufactured by Daicel, Epolid GT401) as a crosslinking agent was changed from 40 parts to 60 parts, and the crosslinking agent was also crosslinked. (v) melamine/formaldehyde/alkyl monoalcohol polycondensate (manufactured by Sanwa Chemical Co., Ltd., Nikalak Mw-100LM) was not blended as an agent, and (vi) 5,5'-[2,2 as a dissolution promoter was not added. , 2-trifluoro-1-(trifluoromethyl)ethylidene]bis[2-hydroxy-1,3-benzenedimethanol] (manufactured by Honshu Kagaku Kogyo Co., Ltd., TML-BPAF-MF) from 10 parts to 5 parts. A photosensitive resin composition was prepared in the same manner as in Example 1, except that the composition was changed to 50%, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Comparative example 6)
In Comparative Example 5, (iv) 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene bisphenol and 6-diazo-5 , 6-dihydro-5-oxo-naphthalene-1-sulfonic acid (2.5 moles) (manufactured by Bigen Shoji Co., Ltd., TPA-525) was changed from 36.3 parts to 20 parts. Except for the above, a photosensitive resin composition was prepared in the same manner as in Comparative Example 5, and each evaluation was performed using the prepared photosensitive resin composition, but most of the coating film was removed during the development process. Because of the elution, only some evaluations (development residual film rate, transmittance, and bubbles during exposure) could be performed. The results are shown in Table 1.

(Comparative Example 7)
In Example 1, (i) the blending amount of the copolymer (A-1) was changed to 100 parts, (ii) the polyamideimide resin having a branched structure was not blended, and (v) epoxy as a crosslinking agent was used. The blending amount of tetrakis(3-cyclohexenylmethyl)butanetetracarboxylate modified ε-caprolactone (manufactured by Daicel Corporation, Epolide GT401) was changed from 40 parts to 60 parts, and (v) melamine formaldehyde as a crosslinking agent was also added. (vi) 5,5'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene] without blending an alkyl monoalcohol polycondensate (manufactured by Sanwa Chemical Co., Ltd., Nikalak Mw-100LM) The same procedure as in Example 1 was carried out, except that the amount of bis[2-hydroxy-1,3-benzenedimethanol] (manufactured by Honshu Kagaku Kogyo Co., Ltd., TML-BPAF-MF) was changed from 10 parts to 5 parts. A photosensitive resin composition was prepared, and each evaluation was performed using the prepared photosensitive resin composition. The results are shown in Table 1.

(Comparative example 8)
In Comparative Example 7, (i) instead of using 100 parts of the copolymer (A-1) having p-vinylphenol monomer units and methyl methacrylate monomer units obtained in Synthesis Example 1, ( ii) A photosensitive resin composition was prepared in the same manner as in Comparative Example 7, except that 100 parts of a polyamide-imide resin having a branched structure (manufactured by DIC Corporation, Unidic EMG-793) was used, and the prepared photosensitive resin composition was We attempted to conduct various evaluations using a polyurethane resin composition, but since most of the coating film was eluted during the development process, only some evaluations (remaining film rate, transmittance, and bubbles during exposure) were possible. I couldn't do it. The results are shown in Table 1.

In Table 1,
"CO" stands for cyclic olefin,
" _TBI " is the thickness of the resin film after immersion in NMP,
" _TAI " is the thickness of the resin film before NMP immersion,
"PB" means pre-bake,
each meaning.

As shown in Table 1 above, Examples 1 to 1 containing the copolymer (A-1) obtained in Synthesis Example 1, a polyamideimide resin having a branched structure, and a naphthylimide group-containing sulfonic acid compound It can be seen that according to the photosensitive resin composition No. 6, a positive resist film having high transmittance, excellent transparency, and excellent heat-resistant shape retention can be formed. Furthermore, when the photosensitive resin compositions of Examples 1 to 5 were used, the resulting coating films had high sensitivity, high resolution in thick films, high development residual film rate, and poor chemical resistance. It can be seen that the results are excellent, and that no bubbles are generated during exposure. In particular, from Examples 1, 5, 6, and Comparative Example 1, the amount of the naphthylimide group-containing sulfonic acid compound is 0.1 parts by mass or more per 100 parts by mass of the polymer and the polyamideimide having a branched structure. It can be seen that by containing in a proportion of .0 parts by mass or less, chemical resistance and heat-resistant shape retention can be further improved.
On the other hand, Comparative Examples 1 to 4 not containing a naphthylimide group-containing sulfonic acid compound, Comparative Examples 5 to 6 not containing the copolymer (A-1) and a polyamideimide resin having a branched structure, and Comparative Examples 5 to 6 not containing a polyamide resin having a branched structure; It can be seen that Comparative Example 7, which does not contain an imide resin, and Comparative Example 8, which does not contain copolymer (A-1), cannot achieve both transparency and heat-resistant shape retention. In particular, it can be seen that in Comparative Examples 3 and 4, the resolution of thick films is also insufficient.
In addition, in Comparative Example 5 in which only the cyclic olefin polymer (A-2) was used instead of the prescribed polymer and polyamide-imide resin having a branched structure, the transmittance of the resist film obtained was It can be seen that the sensitivity was insufficient, the sensitivity was low, the resolution was poor in thick films, and furthermore, bubbles were generated during exposure. In Comparative Example 5, the amount of photosensitizer blended was larger than in the other examples, and as a result, bubbles were generated during exposure. This is when only an alicyclic olefin polymer containing an acidic group (carboxyl group), which has been widely used in positive resist compositions, such as cyclic olefin polymer (A-2), is used as a polymer. In order to obtain a patterned coating film, it is necessary to increase the content of the photosensitizer, but this is because bubbles occur during exposure due to the high content of the photosensitizer.
Furthermore, from Comparative Example 6, when a cyclic olefin polymer (A-2), which is an alicyclic olefin polymer containing acidic groups (carboxyl groups), which has been widely used in positive resist compositions, was used. Furthermore, it can be seen that when the content of the photosensitizer is relatively low, the development residual film rate decreases significantly and it is impossible to obtain a patterned coating film.
Furthermore, it can be seen that in Comparative Example 7, which does not contain a polyamideimide resin having a branched structure, the resulting resist film was insufficient in sensitivity, transmittance, chemical resistance, and resolution in thick films. .
In Comparative Example 8, which did not contain the copolymer (A-1) and only contained a polyamide-imide resin having a branched structure, the solubility in the developer was high, the residual film rate after development was greatly reduced, and patterning was achieved. It can be seen that a coating film cannot be obtained.

According to the photosensitive resin composition of the present invention, it is possible to form a positive resist film and a lens that can achieve both transparency and heat-resistant shape retention at a high level.
Note that the photosensitive resin composition of the present invention can be suitably used in manufacturing micro LEDs, micro OLEDs, organic EL elements, touch panels, and the like.

10 Micro LED
20 Epitaxial wafer 30 N-dot electrode 40 P-pad electrode 50 Protective insulating film 60 Lens

Claims (6)

A polymer having a monomer unit represented by the following general formula (I), a polyamideimide having a branched structure, and a sulfonic acid compound containing a naphthylimide group as a photoacid generator,
The content ratio of the polymer and the polyamide-imide having a branched structure (polymer: polyamide-imide having a branched structure) is 90:10 to 70:30 on a mass basis,
The naphthylimide group-containing sulfonic acid compound is contained in a proportion of 0.1 parts by mass or more and 2.0 parts by mass or less per 100 parts by mass of the polymer and the polyamideimide having a branched structure,
The content of the structural unit represented by structural formula (I) in the polymer is 30% by mass or more and 80% by mass or less,
Photosensitive resin composition.
(In the general formula (I), R ¹ is a chemical single bond or a divalent hydrocarbon group having 1 to 6 carbon atoms which may have a substituent, and R ² is a hydrogen atom, or a monovalent hydrocarbon group having 1 to 6 carbon atoms which may have a substituent.) The photosensitive resin composition according to claim 1, wherein the polyamideimide having a branched structure has a number average molecular weight of 2,000 or more and 30,000 or less. The photosensitive resin composition according to claim 1 or 2, wherein the polymer is a copolymer further having a (meth)acrylate monomer unit. The photosensitive resin composition according to any one of claims 1 to 3, further comprising a photosensitizer and a crosslinking agent. The photosensitive resin composition according to any one of claims 1 to 4, which is used to form a lens. A lens formed from the photosensitive resin composition according to any one of claims 1 to 5.

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