JPWO2019194286A1 - Photosensitive resin composition and pattern structure - Google Patents

Abstract

An object of the present invention is to provide a photosensitive resin composition and a pattern structure capable of forming a gap having a good shape and a high aspect ratio when the pattern structure is formed. The photosensitive resin composition of the present invention is a photosensitive resin composition containing an alkali-soluble binder polymer, a photopolymerizable compound having an ethylenically unsaturated bond, and a photopolymerization initiator, and is a binder polymer. The acid value is 100 mgKOH / g or more and 200 mgKOH / g or less, the photopolymerization initiator is an acylphosphine oxide compound or a titanosen compound, and the content of the photopolymerization initiator is the total solid content of the photosensitive resin composition. This is a photosensitive resin composition having an average I / O value of 1.0% by mass or less and a photopolymerizable compound in the range of 1.1 to 1.5.

Description

The present invention relates to a photosensitive resin composition and a pattern structure formed by using the photosensitive resin composition.

Liquid crystal elements are widely used as electro-optical elements that can be actively driven. In a liquid crystal element, the birefringence of a liquid crystal layer can be changed by applying an electric field to liquid crystal molecules enclosed between a pair of substrates to control the light transmission state, which is combined with a backlight and a color filter. This makes it possible to visually display information and images.
Further, as another electro-optical element, for example, Patent Document 1 proposes a dimming element. In the dimming element, by enclosing a polymer-dispersed liquid crystal between the substrates, it is possible to actively switch the light transmission state by switching between the scattering state and the transmission state by applying an electric field.

In recent years, along with technological advances in sensing methods and sensor blocking, technologies for performing information communication and sensing using light receiving elements other than visible light have been studied. Sensors that use far-infrared light that cannot be perceived by humans and electromagnetic waves such as terahetul waves and millimeter waves have been put into practical use, and as active modulation elements to be combined with them, active similar to the principles of liquid crystal elements and dimming elements described above. Applications of electromagnetic wave devices are being studied (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 7-110463 Japanese Unexamined Patent Publication No. 4-245803

Conventionally known liquid crystal elements and dimming elements have a thin modulation material layer (for example, a liquid crystal layer in a liquid crystal element) sandwiched between substrates (hereinafter, also abbreviated as "gap") for the purpose of use. The ratio of the modulation material layer region to the total area of the device (hereinafter, also abbreviated as “occupancy”) is 90% or more.
However, the design of the gap and occupancy of the modulation material layer changes depending on the application of the active modulation element. For example, considering an active pattern retarder for eliminating polarization in a high frequency band, since the target wavelength is as long as several μm, a gap of about 1 mm is required to give a significant phase difference with conventional materials. The occupancy rate may be about 50%.

Further, in conventionally known liquid crystal elements and dimming elements, it has been studied to provide a spacer with a columnar resin material or inorganic fine particles in order to maintain a gap.
However, it has been conventionally known when a gap having a thickness of several tens of μm or more is provided, especially when the aspect ratio of the modulation material layer (the ratio of the gap thickness to the width of the pattern formed in the modulation material layer) is high. It became clear that the material could not form a well-shaped gap.

Therefore, an object of the present invention is to provide a photosensitive resin composition and a pattern structure having a good shape and capable of forming a gap having a high aspect ratio when the pattern structure is formed.

As a result of pursuing the cause of the gap shape not being formed correctly, the present inventors have not sufficiently spread the irradiation light of the pattern exposure in the film thickness direction, and the film strength in the thickness direction is inclined. It was found that the cause was that the developer penetrated into the pattern part and affected the film quality because it took longer to develop than the thin film pattern.

Therefore, as a result of diligent studies on the above causes, the present inventors have blended a binder polymer having a predetermined acid value as an alkali-soluble binder polymer in a negative-type photosensitive resin composition, and used it as a photopolymerization initiator. By blending a specific amount of a compound having excellent photobleaching properties and a photopolymerizable compound satisfying a predetermined I / O value, a pattern structure having a good shape and a high aspect ratio can be obtained. The present invention has been completed by finding that a gap (space region) can be formed.
That is, the present inventors have found that the above problems can be solved by the following configuration.

[1] A photosensitive resin composition containing an alkali-soluble binder polymer, a photopolymerizable compound having an ethylenically unsaturated bond, and a photopolymerization initiator.
The acid value of the binder polymer is 100 mgKOH / g or more and 200 mgKOH / g or less.
The photopolymerization initiator is an acylphosphine oxide compound or a titanocene compound,
The content of the photopolymerization initiator is 1.0% by mass or less based on the total solid content of the photosensitive resin composition.
A photosensitive resin composition in which the average I / O value of the photopolymerizable compound is in the range of 1.1 to 1.5.

[2] The photosensitive resin composition according to [1], wherein the total light transmittance per 0.1 mm thickness of the solid content obtained by removing only the photopolymerization initiator from the photosensitive resin composition is 93% or more. ..

[3] The binder polymer contains at least one of a structural unit represented by the following formula (I), a structural unit represented by the following formula (II), and a structural unit represented by the following formula (III). The photosensitive resin composition according to [1] or [2], which is a polymer having.
Here, in the above formula (I), R ¹ represents a hydrogen atom or a methyl group.
Further, in the above formula (II), R ² represents a hydrogen atom or a methyl group, and R ³ represents an alkyl group or a cycloalkyl group having 1 to 30 carbon atoms.
Further, in the above formula (III), R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a hydroxy group, an aryl group, or an aryl. It represents an oxy group, an aralkyl group, a cycloalkyl group having 5 or more carbon atoms, or a halogen atom, AO represents an oxyalkylene group, m represents an integer of 0 to 5, and s represents an integer of 1 to 5. Represents. when m is 2 to 5, the plurality of R ^5, may be the same or different from each other.

[4] At least one of the photopolymerizable compounds is a compound having at least three ethylenically unsaturated bonds in the molecule and having a structure represented by the following formula (1) in the molecule. 1] The photosensitive resin composition according to any one of [3].

Here, in the above formula (1), * represents a bonding position with a structure other than the structure contained in the compound. A represents an alkylene group having 1 to 8 carbon atoms. However, the hydrogen atom constituting the hydrocarbon of the alkylene group may be substituted with a hydroxyl group or a methyl group. n represents an integer of 1 to 20.

[5] A pattern structure having a substrate and a cured product having a thickness of 50 μm or more and 5 mm or less formed on the substrate using the photosensitive resin composition according to any one of [1] to [4]. ..
[6] The cured product constitutes a plurality of linear pattern portions, and forms a plurality of linear pattern portions.
The pattern structure according to [5], wherein the width W of the space area formed between the adjacent pattern portions among the plurality of linear pattern portions is smaller than the height H of the pattern portions.
[7] The pattern structure according to [6], wherein the height H of the pattern portion with respect to the width W of the space area is 3 or more and 40 or less.

As shown below, according to the present invention, there is provided a photosensitive resin composition and a pattern structure capable of forming a gap having a good shape and a high aspect ratio when the pattern structure is formed. Can be done.

FIG. 1 is a schematic perspective view showing an example of the pattern structure of the present invention. FIG. 2 is an electron micrograph of a pattern portion in the pattern structure produced in Example 1. FIG. 3 is an electron micrograph of a pattern portion in the pattern structure produced in Comparative Example 1. FIG. 4 is an electron micrograph of a pattern portion in the pattern structure produced in Comparative Example 3. FIG. 5A is a schematic view for explaining the taper angle of the pattern portion. FIG. 5B is a schematic view for explaining the taper angle of the pattern portion.

Hereinafter, the present invention will be described in detail.
The description of the constituent elements described below may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.
In the present specification, the numerical range represented by using "~" means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.

Further, in the present specification, as each component, a substance corresponding to each component may be used alone or in combination of two or more. Here, when two or more kinds of substances are used in combination for each component, the content of the component refers to the total content of the substances used in combination unless otherwise specified.
Further, in the notation of a group (atomic group) in the present specification, the notation that does not describe substitution and non-substitution includes those having no substituent as well as those having a substituent. For example, the "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
Further, in the present specification, "(meth) acrylate" represents acrylate and methacrylate, "(meth) acrylic" represents acrylic and methacrylic, and "(meth) acryloyl" represents acryloyl and methacryloyl.

[Photosensitive resin composition]
The photosensitive resin composition of the present invention is a photosensitive resin composition containing an alkali-soluble binder polymer, a photopolymerizable compound having an ethylenically unsaturated bond, and a photopolymerization initiator.
In the present invention, the acid value of the binder polymer is 100 mgKOH / g or more and 200 mgKOH / g or less.
Further, in the present invention, the photopolymerization initiator is an acylphosphine oxide compound or a titanosen compound, and the content of the photopolymerization initiator is 1.0 mass by mass with respect to the total solid content of the photosensitive resin composition. % Or less.
Further, in the present invention, the average I / O value of the photopolymerizable compound is in the range of 1.1 to 1.5.
In such a photosensitive resin composition, a polymerization reaction occurs in the exposed portion due to light irradiation to change the solubility in a developing solution, and a pattern structure may be formed by the difference in solubility between the exposed portion and the unexposed portion. it can.
Hereinafter, each component contained in the photosensitive resin composition of the present invention will be described in detail.

[Binder polymer]
The binder polymer (hereinafter, also abbreviated as “binder”) contained in the photosensitive resin composition of the present invention is an alkali-soluble binder having an acid value of 100 mgKOH / g or more and 200 mgKOH / g or less.

Here, the acid value of the binder adopts the value measured by the following method.
(1) A resin solution (y (g)) having a solid content concentration (x (%)) is diluted with propylene glycol monomethyl ether acetate to prepare a sample solution having a solid content concentration of 1% by mass to 10% by mass.
(2) 0.1 mol / L potassium hydroxide / ethanol solution (potency a) for the above sample solution using a potential difference measuring device (manufactured by Hiranuma Sangyo Co., Ltd., device name "Hiranuma automatic titrator COM-550"). ), And measure the amount of potassium hydroxide / ethanol solution (b (mL)) required by the end of the titration.
(3) Further, titration is performed on water in the same manner as in (2), and the amount of potassium hydroxide / ethanol solution (c (mL)) required by the end point of titration is measured.
(4) The solid acid value of the resin emulsion is determined by calculating with the following formula.
Solid acid value (mgKOH / g) = {5.611 x (bc) x a} / {(x / 100) x y}

When the acid value of the binder is 100 mgKOH / g or more, the solubility due to contact with an alkaline solvent becomes excellent.
Further, when the acid value of the binder is 200 mgKOH / g or less, the linearity of the formed pattern edge, that is, so-called edge roughness, is obtained even in the development process under stronger conditions than before, which is necessary for forming a gap having a large aspect ratio. Is good, and a structure having a smooth surface of the pattern structure can be obtained.

As such an alkali-soluble binder, for example, the resins described in paragraphs [0025] of JP2011-95716A and paragraphs [0033] to [0052] of JP2010-237589 can be used. it can.

The alkali-soluble binder polymer contained in the photosensitive resin composition has a structural unit represented by the following formula (I), and is represented by the structural unit represented by the following formula (II) or the following formula (III). It can be a polymer having at least one of the structural units.

Here, in the above formula (I), R ¹ represents a hydrogen atom or a methyl group, and the structural unit represented by the above formula (I) is a structural unit based on the polymerizable monomer acrylic acid or methacrylic acid. Is.

Further, in the above formula (II), R ² represents a hydrogen atom or a methyl group, and R ³ represents an alkyl group or a cycloalkyl group having 1 to 30 carbon atoms. R ³ is preferably an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group, preferably an alkyl group having 1 to 10 carbon atoms, and an alkyl group having 3 to 8 carbon atoms. Is more preferable.

The structural unit represented by the above formula (II) is a structural unit based on the polymerizable monomer alkyl (meth) acrylate. Specific examples of the alkyl (meth) acrylate include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and the like.

Further, in the above formula (III), R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a hydroxyl group, or an aryl group (for example, phenyl). Group, aryloxy group (eg, phenoxy group, etc.), aralkyl group (eg, benzyl group, etc.), cycloalkyl group with 5 or more carbon atoms or halogen atom, AO indicates oxyalkylene group, m represents an integer of 0 to 5, and s represents an integer of 1 to 5. When m is 2 to 5, the plurality of R ^5s may be the same or different from each other.
Here, the oxyalkylene group is a group represented by [OCnH2n], and n represents 1 to 5. Specific examples thereof include an oxymethylene group, an oxyethylene group, an oxypropylene group and an oxybutylene group.
Further, the alkylene group contained in the aralkyl group is preferably an alkylene group having 1 to 10 carbon atoms.
Further, the cycloalkyl group having 5 or more carbon atoms preferably has 20 or less carbon atoms, and more preferably 10 or less carbon atoms.

The structural unit represented by the above formula (III) is a structural unit based on a (meth) acrylic acid ester having a phenyl group and an oxyalkylene group, which are polymerizable monomers. Specific examples of the (meth) acrylic acid ester having a phenyl group and an oxyalkylene group include 2-phenoxyethyl (meth) acrylate, 2-phenoxypropyl (meth) acrylate, nonylphenyl (meth) acrylate ethoxylated, and propoxy. Nonylphenyl (meth) acrylate, nonylphenyl (meth) acrylate acrylate, 2-phenoxyethyl (meth) acrylate alkoxylated, EO-modified cumylphenol (meth) acrylate, PO-modified cumylphenol (meth) acrylate, EO. Examples thereof include PO-modified cumylphenol (meth) acrylate.

More specifically, a random copolymer of benzyl (meth) acrylate / (meth) acrylic acid, a random copolymer of benzyl (meth) acrylate / acrylic acid, cyclohexyl (meth) acrylate (a) / methyl (meth). Glycidyl (meth) acrylate adduct of acrylate (b) / (meth) acrylic acid copolymer (c), allyl (meth) acrylate / (meth) acrylic acid copolymer, benzyl (meth) acrylate / (meth) Examples thereof include a copolymer of acrylic acid / hydroxyethyl (meth) acrylate. From the viewpoint of better pattern formation, it is preferable to contain a binder having a carboxyl group. By containing a binder having a carboxyl group, the edge roughness tends to be improved.

The content of the alkali-soluble binder polymer contained in the photosensitive resin composition of the present invention is preferably in the range of 30% by mass to 90% by mass, preferably 40% by mass, based on the total solid content of the photosensitive resin composition. It is more preferably in the range of% to 80% by mass, and further preferably in the range of 50% by mass to 70% by mass. Within this range, the stability of the film thickness when a thick coating film is formed is improved, and a coating film having excellent solubility in a developing solution can be formed.

[Photopolymerizable compound]
The photopolymerizable compound contained in the photosensitive resin composition of the present invention is a compound having an ethylenically unsaturated bond and having an average I / O value in the range of 1.1 to 1.5.
Here, the "average I / O value" is the ratio of the mass portion of the photopolymerizable compound to the total mass portion of the total photopolymerizable compound for each photopolymerizable compound, and the I / of the photopolymerizable compound. It is the result of multiplying by the O value and averaging. When a single compound is used as the photopolymerizable compound, the I / O value of the photopolymerizable compound can be used as the average I / O value.

Further, the above I / O value is a value that deals with the polarities of various organic compounds, which are also called (inorganic value) / (organic value), in an organic concept, and is a functional group contribution method in which parameters are set for each functional group. one of. For the above I / O values, see Organic Conceptual Diagram (Yoshio Koda, Sankyo Publishing (1984) KUMAMOTO PHARMACEUTICAL BULLETIN, No. 1, Paragraphs 1 to 16 (1954); Area of Chemistry, Vol. 11, Documents such as No. 10, 719 to 725 (1957); Fragrance Journal, No. 34, No. 97 to 111 (1979); Fragrance Journal, No. 50, No. 79 to 82 (1981); The closer the I / O value is to 0, the more non-polar (more hydrophobic and organic) the organic compound is, and the larger the I / O value is, the more polar (hydrophilic and inorganic) it is. ) Is an organic compound.
In the present invention, the above I / O value is determined by the method described in "New Edition: Organic Conceptual Diagram-Basics and Applications" by Yoshio Koda et al., November 2008, Sankyo Publishing. I) / organic (O) ”value.

Although the details are unknown, the present inventors have determined that the photopolymerizable compound has a specific range of I / O values, that is, a specific balance of hydrophobicity, so that the unexposed portion is soluble in a developer. It is considered that it is possible to suppress the penetration of the developing solution in the exposed portion and to form a pattern according to a desired shape even when a gap having a high aspect ratio is formed.

In the present invention, the average I / O value of the photopolymerizable compound is preferably 1.10 to 1.25 for the reason that the swelling of the formed gap can be suppressed.

The photopolymerizable compound may be a low molecular weight compound or an oligomer as long as it has an ethylenically unsaturated bond.
Specific examples of the photopolymerizable compound include tricyclodecanediol dimethanol diacrylate, in addition to the ethylenically unsaturated double bond-containing monomer described in paragraphs [0023] to [0024] of Patent No. 4098550. , Ethoxylated bisphenol A diacrylate, and bifunctional polymerizable compounds such as these ethylene oxy modified products and propylene oxy modified products.

Other specific examples of the above photopolymerizable compound include trimethylpropan triacrylate, dipentaerythritol hexaacrylate (hereinafter, also abbreviated as “DPHA”), dipentaerythritol (penta / hexa) acrylate, and tripentaerythritol octaacrylate. Examples thereof include polymerizable compounds having at least three ethylenically unsaturated bonds, and these ethyleneoxy-modified compounds and propyleneoxy-modified compounds can also be preferably used depending on the intended purpose.
Further, a urethane-based monomer such as a urethane (meth) acrylate compound can also be preferably used.

In the present invention, the photopolymerizable compound preferably has two or three ethylenically unsaturated bonds for the reason that the shape of the gap formed is better. It is more preferable to have.

In the present invention, at least one of the above photopolymerizable compounds has at least three ethylenically unsaturated bonds in the molecule and has a structure represented by the following formula (1) in the molecule. It is preferably a compound (hereinafter, also abbreviated as "specific monomer").

In the above formula (1), * represents a bonding position with a structure other than the above structure contained in the specific monomer. A represents an alkylene group having 1 to 8 carbon atoms. However, the hydrogen atom constituting the hydrocarbon of the alkylene group may be substituted with a hydroxyl group or a methyl group. n represents an integer of 1 to 20.
Here, A is ethylene _(-CH 2 -CH ₂ -) when it is are referred to as poly (ethyleneoxy), propylene _{(-CH 2 -CH (CH 3)} -) is when a poly (propyleneoxy ) Is sometimes called.

Although the details are unknown, the present inventors have excellent solubility in the unexposed portion due to the balance between the hydrophobicity derived from the alkylene group and the hydrophilicity derived from the ether group due to having such a structure. It is considered that the pattern forming property can be improved by excellent cross-linking property and strongly suppressing the swelling of the exposed portion.

The content of the photopolymerizable compound having an ethylenically unsaturated bond is preferably 10% by mass or more, more preferably 20% by mass or more, in the total solid content of the photosensitive resin composition. , 25% by mass or more, and particularly preferably 30% by mass or more. The upper limit is not particularly determined, but for example, it is preferably 99% by mass or less, and more preferably 95% by mass or less. Further, when the inorganic particles described later are blended, it is preferably 80% by mass or less, and more preferably 75% by mass or less.

[Photopolymerization initiator]
The photopolymerization initiator contained in the photosensitive resin composition of the present invention is an acylphosphine oxide compound or a titanocene compound.
The content of the photopolymerization initiator is 1.0% by mass or less with respect to the total solid content of the photosensitive resin composition.
The acylphosphine oxide compound and the titanosen compound have a so-called photobleaching property in which the extinction coefficient of the excitation light band is reduced by irradiation with excitation light for initiation of polymerization.

Generally, in a photopolymerization initiator, molecules are excited by irradiating light with an excitation wavelength, and a polymerization active species is produced by a cleavage reaction or the like. Since the amount of polymerized active species produced is roughly proportional to the amount of light energy that reaches the molecule, it is necessary to apply a certain amount of light energy in order to sufficiently proceed with the polymerization reaction. However, according to Lambert-Beer's law, the irradiated light is absorbed in the layer and decays exponentially toward the film thickness. Therefore, in the thick layer intended by the present invention, the layer is separated from the surface on the light incident side. The polymerization reaction becomes more difficult to proceed as it enters the inside of. As a result, it is considered that a pattern contrary to the intention such as the pattern becomes thin is formed, the strength of the pattern is insufficient, and problems such as pattern collapse and deterioration of edge roughness occur.

As a result of studies by the present inventors, when a photopolymerization initiator having a photobleaching property is added at a specified concentration, photobleaching occurs appropriately, and the photobleaching property allows a sufficient polymerization reaction to the inside of the layer. I think it will progress to. As a result, it is presumed that a pattern having an intended shape can be formed without thinning of the pattern and deterioration of pattern collapse and edge roughness.

As specific examples of the acylphosphine oxide compound, Lucirin TPO, Irgacure 819 (all manufactured by BASF) and the like are exemplified as commercially available products, and JP-A-63-40799, JP-A-5-29234, JP-A-JP Examples of the compounds described in Japanese Patent Application Laid-Open No. 10-95788, JP-A-10-29997, and the like can be mentioned.
Since the acylphosphine oxide compound has an absorption band of 430 nm or less in the unexposed state and becomes substantially colorless by exposure, it can be preferably used in applications where it is desirable that the pattern structure is colorless in the visible region.

As a specific example of the titanocene compound, Irgacure 784 (manufactured by BASF) is exemplified as a commercially available product, and European Patent Application Publication No. 122223, JP-A-63-41483, JP-A-63- Examples of the compounds described in JP-A-41484, JP-A-2-249, JP-A-2-291, JP-A-3-12403, JP-A-3-27393 and the like can be mentioned.
Since the titanocene compound generally has an absorption band up to around 550 nm in the unexposed state, visible light can be used as an exposure light source. For example, when it is necessary to provide a pattern structure on a substrate or the like containing an ultraviolet absorber for light resistance, pattern exposure can be performed without being affected by the ultraviolet absorber, which is preferable.

In the present invention, the content of the photopolymerization initiator is preferably 0.01 to 1.0% by mass, more preferably 0.01% by mass or more and less than 1.0% by mass, and 0. It is more preferably 1 to 0.7% by mass. Within this range, a tough pattern can be formed with a high polymerization rate, and coloring by unreacted components or reaction products of these photopolymerization initiators is unlikely to occur, and the polymerization reaction is completed deep into the photosensitive resin composition layer. Can be made to.

In the present invention, for the reason that pattern formation becomes easy, the total light transmittance per 0.1 mm thickness of the solid content obtained by removing only the photopolymerization initiator from the photosensitive resin composition of the present invention is 93%. The above is preferable. This is because the components other than the photopolymerization initiator do not have light absorption, so that the light incident from the light source reaches the inside of the film without being absorbed or scattered on the light source side. Therefore, it is the object of the present invention. This is because it greatly contributes to a certain good pattern formation.
Here, the total light transmittance is a 0.1 mm thick film obtained by applying a composition obtained by removing only the photopolymerization initiator from the photosensitive resin composition of the present invention, drying the film, and solid-differentiating the film (hereinafter, “sample”). The value measured by the method according to JIS K 7375: 2008 is adopted for (abbreviated as "membrane").
Specifically, a transparent support (for example, glass) is used as the background, and the value measured by measuring the total light transmittance of the sample film on the support and removing the background is adopted.

[Surfactant]
The photosensitive resin composition of the present invention may contain a surfactant.
As the surfactant, any of anionic, cationic, nonionic, or amphoteric surfactants can be used, but the preferred surfactant is a nonionic surfactant. As the surfactant, a nonionic surfactant is preferable, and a fluorine-based surfactant is more preferable.
Examples of the surfactant that can be used in the present invention include commercially available products, Megafuck F142D, F172, F173, F176, F177, F183, F479, F482, F554, and F780. , F781, F781-F, R30, R08, F-472SF, BL20, R-61, R-90 (manufactured by DIC Co., Ltd.), Florard FC-135, FC-170C, FC-430, FC-431, Novec FC-4430 (manufactured by Sumitomo 3M Ltd.), Asahi Guard AG7105, 7000, 950, 7600, Surfron S-112, S-113, S-131, S -141, S-145, S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by Asahi Glass Co., Ltd.), Examples thereof include Ftop EF351, 352, 801 and 802 (manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) and Surfactant 250 (manufactured by Neos Co., Ltd.). In addition to the above, KP (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow (manufactured by Kyoeisha Chemical Co., Ltd.), Ftop (manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.), Megafuck (manufactured by DIC Corporation) , Florard (manufactured by Sumitomo 3M Ltd.), Asahi Guard, Surflon (manufactured by Asahi Glass Co., Ltd.), PolyFox (manufactured by OMNOVA), and the like.

〔solvent〕
A solvent may be added to the photosensitive resin composition of the present invention, if necessary. By diluting with a solvent, the viscosity can be adjusted to be suitable for coating, and the constituent components can be uniformly mixed.
As the organic solvent used, known solvents can be used, such as ethylene glycol monoalkyl ethers, ethylene glycol dialkyl ethers, ethylene glycol monoalkyl ether acetates, propylene glycol monoalkyl ethers, and propylene glycol dialkyl ethers. , Propropylene glycol monoalkyl ether acetates, Diethylene glycol dialkyl ethers, Diethylene glycol monoalkyl ether acetates, Dipropylene glycol monoalkyl ethers, Butylene glycol diacetates, Dipropylene glycol dialkyl ethers, Dipropylene glycol monoalkyl ether acetates , Alcohols, esters, ketones, amides, lactones and the like can be exemplified.

The boiling point of the solvent is preferably 100 ° C. to 300 ° C., more preferably 120 ° C. to 250 ° C. from the viewpoint of coatability.
The organic solvent that can be used in the present invention may be used alone or in combination of two or more. It is also preferable to use solvents having different boiling points together.

The content of the organic solvent in the photosensitive resin composition of the present invention is preferably 3 to 50% by mass, more preferably 20 to 40% by mass as the solid content concentration from the viewpoint of adjusting the viscosity to be suitable for coating. Can be added as such.

[Other ingredients]
Other components such as a plasticizer, a polymerization inhibitor, an antioxidant, and an adhesion improver can be added to the photosensitive resin composition of the present invention, if necessary. Further, various ultraviolet absorbers, metal inactivating agents and the like described in "New Development of Polymer Additives (Nikkan Kogyo Shimbun Co., Ltd.)" may be added to the photosensitive resin composition of the present invention. ..
Further, it is preferable that the photosensitive resin composition of the present invention does not substantially contain pigments and dyes. In addition, "substantially not contained" means that the amount is less than 0.1% by mass with respect to the total solid content of the photosensitive resin composition.

The photosensitive resin composition of the present invention preferably has an I / O value of 0.5 to 1.5, preferably 0.7 to 1.0, for the reason that swelling of the formed gap can be suppressed. Is more preferable.
Here, the I / O value of the photosensitive resin composition refers to a value obtained by multiplying the I / O value by the molar ratio for each component contained in the photosensitive resin composition and summing them up.

[Pattern structure]
The pattern structure of the present invention is a pattern structure having a substrate and a cured product having a thickness of 50 μm or more and 5 mm or less formed on the substrate using the photosensitive resin composition of the present invention.
The thickness of the cured product is preferably 70 μm to 3 mm.

In the pattern structure of the present invention, it is preferable that the cured product constitutes the pattern portion.
Examples of the shape of the pattern portion include a linear shape, a striped shape, and a grid shape.

In the pattern structure of the present invention, the cured product constitutes a plurality of linear pattern portions, and the width W of the space region formed between the adjacent pattern portions among the plurality of linear pattern portions is large. , It is preferable that the height H of the pattern portion is smaller than the height H of the pattern portion (that is, H> W), and the height H of the pattern portion with respect to the width W of the space region, that is, the aspect ratio (H / W) is 3 or more and 40 or less. Is preferable.
Although it is difficult to form such a groove having a high aspect ratio using a conventionally well-known resist-like pattern-forming material, a suitable shape can be obtained by using the photosensitive resin composition of the present invention. It is possible to provide with.

FIG. 1 is a schematic perspective view showing an example of the pattern structure of the present invention.
The pattern structure 10 shown in FIG. 1 has a substrate 1, a metal film 2 provided on the substrate 1, and a pattern portion 3 provided in a stripe shape on the transparent electrode 2, and the pattern portions 3 are connected to each other. It is a structure in which a space region 4 is formed between them.
Further, in FIG. 1, the reference numeral H represents the height of the pattern portion, and the reference numeral W represents the width of the space area.

〔substrate〕
Examples of the substrate include an inorganic substrate, a resin substrate, and a resin composite material.
Examples of the inorganic substrate include glass, quartz, silicon, silicon nitride, and a composite substrate in which molybdenum, titanium, aluminum, copper, etc. are vapor-deposited on such a substrate.
As the resin substrate, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polystyrene, polycarbonate, polysulfone, polyether sulfone, polyarylate, allyl diglycol carbonate, polyamide, polyimide, polyamideimide, polyetherimide, Fluororesin such as polybenzazole, polyphenylene sulfide, polycycloolefin, norbornene resin, polychlorotrifluoroethylene, liquid crystal polymer, acrylic resin, epoxy resin, silicone resin, ionomer resin, cyanate resin, crosslinked fumaric acid diester, cyclic polyolefin, Examples thereof include substrates made of synthetic resins such as aromatic ethers, maleimide-olefins, celluloses, and episulfide resins.

[Metal film]
Since the photosensitive resin composition of the present invention has good adhesion to a metal film or metal oxide film formed by vapor deposition or sputtering, the pattern structure of the present invention is a metal formed by sputtering on the substrate. It is preferable to have a film.
The metal is preferably titanium, copper, aluminum, indium, tin, manganese, nickel, cobalt, molybdenum, tungsten, chromium, silver, neodium and oxides or alloys thereof, and molybdenum, titanium, aluminum, copper and These alloys are more preferred. The metal or metal oxide may be used alone or in combination of two or more.
Further, the metal film may be an oxide, a nitride, or a carbide of the above metal.

[Manufacturing method of pattern structure]
As a method for producing the pattern structure of the present invention, a known method can be used without particular limitation, but it is preferable to include the following steps (1) to (3) and (5).
(1) Coating step of applying the photosensitive resin composition of the present invention on a substrate (2) Solving solvent removing step of removing a solvent from the applied photosensitive resin composition (3) Photosensitive resin from which an organic solvent has been removed Curing step of curing the composition with light (5) Development step of removing an unexposed portion by development Further, it is preferable to further include the following step (4) between the steps (3) and (5). .. Further, it is preferable to include the following step (6) after the step (5).
(4) Heat treatment step of heat-treating the cured product cured by light (6) Post-cure step of further exposing or heating the formed pattern structure.

In the coating step (1), the photosensitive resin composition of the present invention can be applied onto a substrate to form a wet film containing a solvent. Before applying the photosensitive resin composition to the substrate, the substrate can be cleaned such as alkaline cleaning or plasma cleaning. Further, after cleaning the substrate, the surface of the substrate can be treated with hexamethyldisilazane or the like. By performing this treatment, the adhesion of the photosensitive resin composition to the substrate can be improved.

The method of applying the photosensitive resin composition of the present invention to a substrate is not particularly limited, and for example, an inkjet method, a slit coating method, a spray method, a roll coating method, a rotary coating method, a cast coating method, a slit and spin method, and the like. A method such as a printing method can be used.

In the solvent removing step (2), it is preferable to remove the solvent from the coated film by vacuuming and / or heating to form a dry coating film on the substrate. The heating conditions of the solvent removing step are preferably about 30 to 300 seconds at 70 to 130 ° C.
Further, in the solvent removing step, it is not necessary to completely remove the organic solvent in the photosensitive resin composition, but at least a part thereof may be removed.

The curing step (3) is a step of pattern-curing the coating film from which the organic solvent has been removed by generating radicals from the photopolymerization initiator by pattern exposure and performing polymerization. The light irradiation means that can be used in the step (3) is not particularly limited as long as it can be cured, but the exposure light source by the active light includes a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, and an LED light source. An excimer laser generator or the like can be used, and active light having a wavelength of 300 nm or more and 450 nm or less such as g-line (436 nm), i-line (365 nm), and h-line (405 nm) can be preferably used. Further, if necessary, the irradiation light can be adjusted through a spectral filter such as a long wavelength cut filter, a short wavelength cut filter, and a bandpass filter. Further, the parallelism of the irradiation light can be increased by passing it through a collimator or a louver. It is preferable that 80% or more of the total ray energy is in the range of ± 20 ° from the direction of the main ray, in the range of ± 15 °, and further in the range of ± 10 °.
As the exposure device, various types of exposure machines such as a mirror projection aligner, a stepper, a scanner, a proximity, a contact, a microlens array, and a laser exposure can be used.

When the pattern exposure method using a mask is adopted, it is preferable that the distance between the mask and the coating film is short because the pattern is formed more accurately. However, the pattern structure of the present invention is different from a normal resist pattern. The surface shape of the cured film portion may have to be smooth, and it is preferable to expose the mask and the coating film without contacting each other. The distance between the coating film and the mask can be preferably 20 μm or more and 200 μm or less, and more preferably 50 μm or more and 150 μm or less. With this interval, unexpected contact due to the flow of the atmosphere does not occur, the pattern can be precisely controlled, and a preferable taper angle can be formed. It is also possible to prevent contact due to air fluctuation by reducing the pressure between the coating film and the mask during exposure.

The heat treatment step (4) is performed as necessary to complete the polymerization reaction and increase the film strength of the exposed region. When the solvent is not completely removed in the step (1), it is preferable to completely remove the solvent in this step. Further, the durability of various products including the pattern structure of the present invention can be improved by completely removing volatile components other than the solvent by performing vacuum treatment, decompression treatment, or heat treatment at 150 ° C. or higher. it can.

In the developing step (5), a so-called developing process is performed in which the unexposed portion is removed by dissolving or dispersing it in a developing solution to form a gap. As a method of such development processing, for example, a dipping method, a rocking method, a shower method, a spray method, a paddle method or the like can be used. Further, the development processing conditions can be appropriately adjusted, and for example, the type or composition of the developer, the concentration of the developer, the development time, the development temperature, and the like can be appropriately determined.

A good pattern shape can be realized by using an alkaline developer when forming the pattern structure of the present invention.
Specific examples of the active component of such an alkaline developing solution include lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium hydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, and hydrogen phosphate. Disodium, ammonium dihydrogen phosphate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, lithium silicate, sodium silicate, potassium silicate, lithium carbonate, sodium carbonate, potassium carbonate, lithium borate, sodium borate, Inorganic alkaline compounds such as potassium borate and ammonia; tetramethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, ethanolamine and the like. Examples include organic alkaline compounds.

As the alkaline developer, the above-mentioned alkaline compounds can be used alone or in combination of two or more. Usually, it can be dissolved in water to prepare an alkaline developer.
The concentration of the above-mentioned alkaline compound is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass.
Within this density range, development proceeds satisfactorily even with a pattern having a high aspect ratio, and surface roughness due to the surface of the cured portion being affected can be prevented. After the development treatment with the above-mentioned alkaline developer, it is preferable to carry out a water washing treatment.

The obtained pattern structure of the present invention is sealed by filling the gap portion with an arbitrary component and providing an arbitrary other substrate so as to be in contact with the pattern structure on the surface opposite to the surface in contact with the base material. It can be stopped, etc.
For example, a medium whose transparency, refractive index anisotropy, light absorption spectrum, and permittivity change due to electromagnetic waves is enclosed in the gap of the pattern structure, and various characteristics are actively changed by applying an electric or magnetic field from the outside. It is possible to construct an element that can be formed.
It can also be used as a dynamic sensor by enclosing a fluid medium (including air) in the gap and detecting the flow by pressure.
In particular, the composition of the present invention and the pattern of the present invention are used in these applications in which a thickness of 50 μm or more, a high aspect ratio, and a precise gap shape are required, which is difficult with conventionally known photosensitive resin compositions. The structure is extremely useful.

Hereinafter, a detailed description will be given with reference to examples. In addition,% and part described in an Example are weight units unless otherwise specified. The polystyrene-equivalent weight average molecular weight (hereinafter referred to as Mw) was measured in polystyrene-equivalent by gel permeation chromatography (GPC) (trade name: HLC-802A) manufactured by Tosoh Corporation.

<Synthesis of alkali-soluble binder polymer>
As the alkali-soluble binder polymer, the following copolymers synthesized at the monomer ratios in Table 1 below were prepared. In Table 1 below, BzMA represents benzyl methacrylate, MAA represents methyl methacrylate, and AA represents acrylic acid.

[Example 1]
<Preparation of photosensitive resin composition>
The following composition was prepared as the photosensitive resin composition P1.
―――――――――――――――――――――――――――――――――
Photosensitive resin composition P1
―――――――――――――――――――――――――――――――――
-Alkali-soluble binder B1 (I / O value: 0.55) 60 parts by mass-Photopolymerizable compound A
(A-GLY-9E, manufactured by Shin-Nakamura Chemical Co., Ltd., I / O value: 1.24)
40 parts by mass, photopolymerization initiator (Irgacure TPO, manufactured by BASF, I / O value: 1.56)
0.5 parts by mass, surfactant (Megafuck F-554, manufactured by Dic, I / O value: 2.33)
0.1 parts by mass, solvent 0.9 parts by mass ――――――――――――――――――――――――――――――――――

<Making a pattern structure>
The above-mentioned photosensitive resin composition P1 was applied by spin coating on a 40 × 40 mm glass substrate and dried at 90 ° C. for 15 minutes to form a coating film (film thickness after drying: 100 μm).
Next, a mask exposure [mask pattern: L (transparent part) / S (light-shielding part) = 300 μm / 30 μm] was applied to this coating film using a proximity exposure machine (UIS-5011 manufactured by Ushio, Inc.). went. The exposure amount was 100 mJ / cm ^{2 on} average in the exposure area, and a gap of 100 μm was provided between the mask and the coating film.
The pattern-exposed coating film is developed with a small developing machine AD-1200 (manufactured by MIKASA Co., Ltd.) using a 0.05 mass% KOH aqueous solution in a shower for 5 minutes to remove unexposed areas. , A pattern structure in which a pattern portion (width: 300 μm, height: 100 μm) and a space region (width: 30 μm, height: 100 μm, aspect ratio: 3.3) was formed on the substrate was produced.
FIG. 2 shows an electron micrograph of a pattern portion in the pattern structure produced in Example 1.

[Examples 2 to 7 and Comparative Examples 1 to 6]
A pattern structure was produced in the same manner as in Example 1 except that the photosensitive resin composition shown in Table 2 below was used instead of the photosensitive resin composition P1.
FIG. 3 shows an electron micrograph of the pattern portion in the pattern structure produced in Comparative Example 1, and FIG. 4 shows an electron micrograph of the pattern portion in the pattern structure produced in Comparative Example 3.

[Total light transmittance]
A composition obtained by removing the photopolymerization initiator from the photosensitive resin composition was prepared, and a coating film was provided on a glass substrate washed with alkali so that the film thickness after removing the solvent with a spin coater was 100 μm. Based on JIS K 7375: 2008, the total light transmittance was measured with the glass substrate as the background. The results are shown in Table 2 below.

[I / O value]
The I / O value of the photosensitive resin composition was calculated by the method described above. The results are shown in Table 2 below.

[Morphological evaluation]
The remaining film of the formed pattern structure, the swelling of the pattern portion, and the taper angle of the pattern portion were measured. The evaluation criteria are as follows. The evaluation results are shown in Table 3 below.

<Residual membrane>
By cutting the produced pattern structure and observing the cross section with an electron microscope, the residual film R in the unexposed portion was determined according to the following criteria.
A: R <0.05 μm
B: 0.05 μm ≤ R <0.2 μm
C: 0.2 μm ≤ R <1 μm
D: 1 μm ≤ R

<Swelling>
The area of the flat surface portion of the produced pattern structure of 3 × 3 mm was observed with an electron microscope, and the swelling of the cured film was evaluated from the area S where the pattern portion was collapsed according to the following criteria.
A: S <1%
B: 1% <S <5%
C: 5% <S <20%
D: 20% ≤ S

<Taper angle>
The prepared pattern structure was cut, the cross section thereof was observed with an electron microscope, and the angle formed by the pattern portion was measured by image analysis. The taper angle θ shown in FIGS. 5A and 5B was measured and evaluated according to the following criteria. .. Note that θ = 0 ° is defined as the angle perpendicular to the substrate.
A: θ <± 3 °
B: ± 3 ° ≤ θ <± 10 °
C: ± 10 ° ≤ θ <± 20 °
D: ± 20 ° ≤ θ
E: Cannot be evaluated

From the results shown in Tables 2 and 3, when the content of the photopolymerization initiator is more than 1.0% by mass with respect to the total solid content of the photosensitive resin composition, the taper angle becomes large and the gap shape is inferior. It was found (Comparative Example 1).
Further, it was found that when the average I / O value of the photopolymerizable compound was out of the range of 1.1 to 1.5, the taper angle became large and the shape of the gap was inferior (Comparative Examples 2 to 3).
It was also found that when the acid value of the binder polymer was outside the range of 100 mgKOH / g or more and 200 mgKOH / g or less, the taper angle became large and the shape of the gap was inferior (Comparative Examples 4 to 5).
Further, it was found that when a photopolymerization initiator that does not correspond to any of the acylphosphine oxide compound and the titanocene compound was used, the taper angle became large and the shape of the gap was inferior (Comparative Examples 4 to 5).

On the other hand, the acid value of the binder polymer is 100 mgKOH / g or more and 200 mgKOH / g or less, the photopolymerization initiator is an acylphosphine oxide compound or a titanosen compound, and the content of the photopolymerization initiator is photosensitive. It is formed when the content is 1.0% by mass or less based on the total solid content of the sex resin composition, and the average I / O value of the photopolymerizable compound is in the range of 1.1 to 1.5. It was found that the shape of the gap was good despite the high aspect ratio (Examples 1 to 7).
In particular, from the comparison between Example 1 and Example 2, it was found that when the average I / O value of the photopolymerizable compound was 1.10 to 1.25, the swelling of the formed gap could be further suppressed.
Further, from the comparison of Examples 1, 4 and 5, when the content of the photopolymerizable compound is 0.2 to 0.7% by mass with respect to the total solid content of the photosensitive resin composition, the shape of the gap Was found to be better.
Further, from the comparison between Example 1 and Example 6, when the photopolymerizable compound is a compound having two or three ethylenically unsaturated bonds, the shape of the gap may be better. Do you get it.
Further, from the comparison between Example 1 and Example 7, it was found that when the I / O value of the photosensitive resin composition is 0.7 to 1.0, the swelling of the formed gap can be further suppressed.

1 Substrate 2 Metal film 3 Pattern part 4 Space area 10 Pattern structure

Claims (7)

A photosensitive resin composition containing an alkali-soluble binder polymer, a photopolymerizable compound having an ethylenically unsaturated bond, and a photopolymerization initiator.
The acid value of the binder polymer is 100 mgKOH / g or more and 200 mgKOH / g or less.
The photopolymerization initiator is an acylphosphine oxide compound or a titanocene compound.
The content of the photopolymerization initiator is 1.0% by mass or less based on the total solid content of the photosensitive resin composition.
A photosensitive resin composition in which the average I / O value of the photopolymerizable compound is in the range of 1.1 to 1.5. The photosensitive resin composition according to claim 1, wherein the total light transmittance per 0.1 mm thickness of the solid content obtained by removing only the photopolymerization initiator from the photosensitive resin composition is 93% or more. The binder polymer has a structural unit represented by the following formula (I), a structural unit represented by the following formula (II), and at least one of the structural units represented by the following formula (III). The photosensitive resin composition according to claim 1 or 2, which is a polymer.
Here, in the above formula (I), R ¹ represents a hydrogen atom or a methyl group.
Further, in the above formula (II), R ² represents a hydrogen atom or a methyl group, and R ³ represents an alkyl group or a cycloalkyl group having 1 to 30 carbon atoms.
Further, in the above formula (III), R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a hydroxy group, an aryl group, or an aryl. It represents an oxy group, an aralkyl group, a cycloalkyl group having 5 or more carbon atoms, or a halogen atom, AO represents an oxyalkylene group, m represents an integer of 0 to 5, and s represents an integer of 1 to 5. Represents. when m is 2 to 5, the plurality of R ^5, may be the same or different from each other. Claim 1 is a compound in which at least one of the photopolymerizable compounds has at least three ethylenically unsaturated bonds in the molecule and has a structure represented by the following formula (1) in the molecule. The photosensitive resin composition according to any one of 3 to 3.
Here, in the formula (1), * represents a bonding position with a structure other than the structure contained in the compound. A represents an alkylene group having 1 to 8 carbon atoms. However, the hydrogen atom constituting the hydrocarbon of the alkylene group may be substituted with a hydroxyl group or a methyl group. n represents an integer of 1 to 20. A pattern structure having a substrate and a cured product having a thickness of 50 μm or more and 5 mm or less formed on the substrate using the photosensitive resin composition according to any one of claims 1 to 4. The cured product constitutes a plurality of linear pattern portions, and forms a plurality of linear pattern portions.
The pattern structure according to claim 5, wherein the width W of the space region formed between the adjacent pattern portions among the plurality of linear pattern portions is smaller than the height H of the pattern portions. The pattern structure according to claim 6, wherein the height H of the pattern portion with respect to the width W of the space region is 3 or more and 40 or less.