Photosensitive resin composition, photosensitive resin film, photosensitive dry film, patterning method, display device, and micro LED display

Abstract

The present invention relates to a photosensitive resin composition containing (A) an acrylic resin having a (meth)acryloyl group in a side chain thereof, (B1) quantum dots, (B2) a thiol ligand coordinated to the surface of the quantum dots, the thiol ligand including one of poly(ethylene oxide), poly(propylene oxide), a poly(ethylene oxide) block copolymer, and a poly(propylene oxide) block copolymer, (C) a photoradical generator which is a carbazole-based oxime ester compound, (D) light-scattering particles having a refractive index of 1.90 or more and an average particle size of 100-400 nm, (E) a surfactant, and (F) a solvent. Accordingly, the present invention provides: a photosensitive resin composition with which a film having high lithography resolution, good optical properties, chemical resistance, and reliability can be easily formed; a photosensitive resin film; a photosensitive dry film; a patterning method which uses the photosensitive resin composition, the photosensitive resin film, and the photosensitive dry film; and a display device and a micro LED display which use the photosensitive resin composition.

Description

Photosensitive resin composition, photosensitive resin coating, photosensitive dry film, pattern forming method, display device, and microLED display

[0001] The present invention relates to a photosensitive resin composition, a photosensitive resin coating, a photosensitive dry film, a pattern forming method, a display device, and a microLED display.

[0002] Various methods have been proposed to form displays containing red, green, and blue subpixels. One such method involves converting light from an LED array, from shorter wavelengths (blue) to longer wavelengths (red and green), through a color conversion structure. Quantum dots are used to perform this color conversion.

[0003] In recent years, these LED arrays have become micro-sized, and micro-LED displays using them have attracted attention. One method for forming color conversion structures on LED arrays is a lithography process using photosensitive materials (Patent Document 1), but in recent years, further miniaturization has been required for application to small displays. Furthermore, there are high demands for optical properties, chemical resistance, and reliability.

[0004] Japanese Patent Publication No. 2024-70567

[0005] The present invention has been made in view of the above circumstances, and aims to provide a photosensitive resin composition that can easily form a film having high lithography resolution, good optical properties and chemical resistance, and reliability; a photosensitive resin film obtained using the photosensitive resin composition; a photosensitive dry film; a pattern forming method using the same; and a display device and a microLED display obtained using the photosensitive resin composition.

[0006] To solve the above problems, the present invention provides a photosensitive resin composition comprising: (A) an acrylic resin having a (meth)acryloyl group in its side chain; (B1) quantum dots; (B2) a thiol ligand coordinated to the surface of the quantum dots, comprising one of poly(ethylene oxide), poly(propylene oxide), poly(ethylene oxide) block copolymer, and poly(propylene oxide) block copolymer; (C) a photoradical generator which is a carbazole oxime ester compound; (D) light scattering particles having a refractive index of 1.90 or higher and an average particle diameter of 100 to 400 nm; (E) a surfactant; and (F) a solvent.

[0007] Such a photosensitive resin composition allows for the easy formation of a cured film with high lithographic resolution, good optical properties, and chemical resistance.

[0008] Furthermore, in the present invention, it is preferable that the surface of the light scattering particles of component (D) is modified with aluminum hydroxide.

[0009] Such a photosensitive resin composition can suppress the formation of aggregates and create highly sensitive patterns with good shapes.

[0010] Furthermore, in the present invention, it is preferable that component (D) is contained in the non-volatile components of the photosensitive resin composition in an amount of 2 to 40% by mass.

[0011] Such a photosensitive resin composition allows for the formation of fine patterns while maintaining good luminescence properties.

[0012] Furthermore, in the present invention, it is preferable that the (B1) component has a core-shell structure including a core and a shell covering the core, the core contains one or more compounds consisting of a combination of two or more of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Ag, Hg, N, As, and O, and the shell contains one or more compounds consisting of a combination of two or more of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Hg, N, As, O, Mn, and Sr.

[0013] Such a photosensitive resin composition is preferable because it exhibits good optical properties.

[0014] Furthermore, in the present invention, it is preferable that the (B1) component is contained in the non-volatile components of the photosensitive resin composition in an amount of 10 to 50% by mass.

[0015] Such a photosensitive resin composition allows for the formation of fine patterns while maintaining good luminescence properties.

[0016] Furthermore, in the present invention, it is preferable that the (B2) component is present in an amount of 10 to 45 parts by mass per 100 parts by mass of the (B1) component.

[0017] Such a photosensitive resin composition can suppress the formation of aggregates and create highly sensitive patterns with good shapes.

[0018] Furthermore, in the present invention, it is preferable that component (C) has a maximum absorption wavelength of 350 nm or more and is present in the non-volatile components of the photosensitive resin composition in an amount of 0.1 to 1.5% by mass.

[0019] With such a photosensitive resin composition, radical species are generated efficiently, and good pattern formation can be achieved without development peeling.

[0020] Furthermore, the photosensitive resin composition of the present invention may also contain a polyfunctional (meth)acrylate having a (F) double bond equivalent of 300 g / mol or less.

[0021] With such a photosensitive resin composition, the crosslinking density can be increased to form a pattern with a good shape after development.

[0022] Furthermore, the present invention provides a photosensitive resin film which is a dried body of the photosensitive resin composition described above.

[0023] Such a photosensitive resin coating would result in a coating with high lithography resolution, good luminescence properties, and chemical resistance.

[0024] Furthermore, the present invention provides a photosensitive dry film comprising a support film and a photosensitive resin coating described above on the support film.

[0025] The photosensitive dry film of the present invention can achieve high flatness when adhered to an uneven substrate.

[0026] Furthermore, the present invention provides a pattern forming method comprising: (i) applying the above-described photosensitive resin composition onto a substrate to form a photosensitive resin film on the substrate; (ii) exposing the photosensitive resin film to light; and (iii) developing the exposed photosensitive resin film with a developer solution to dissolve and remove the unexposed areas and form a pattern.

[0027] This pattern formation method allows for the creation of patterns with high lithographic resolution, resulting in a cured film with excellent luminescence properties and chemical resistance.

[0028] Furthermore, the present invention provides a pattern forming method comprising: (i') a step of attaching the photosensitive resin film of the photosensitive dry film described above to a substrate to form the photosensitive resin film on the substrate; (ii) a step of exposing the photosensitive resin film to light; and (iii) a step of developing the exposed photosensitive resin film with a developer solution to dissolve and remove the unexposed areas to form a pattern.

[0029] This pattern formation method using a photosensitive dry film allows for the formation of patterns with high lithographic resolution, and enables the creation of a cured film with good luminescence properties and chemical resistance.

[0030] Further, the present invention provides a display device comprising a cured film obtained by patterning the photosensitive resin composition described above.

[0031] The cured film obtained from the photosensitive resin composition of the present invention can form fine patterns, and has favorable light-emitting properties and chemical resistance, so it can be suitably used for display devices.

[0032] Further, the present invention provides a display device that comprises a cured film obtained by patterning the photosensitive resin composition described above on an upper portion of a blue LED, and extracts light color-converted by quantum dots from each subpixel.

[0033] The cured film obtained from the photosensitive resin composition of the present invention has favorable light-emitting properties, so it can be suitably used for display devices.

[0034] Furthermore, the present invention provides a 0.01 mm ２ or less cured film obtained by patterning the photosensitive resin composition described above on an upper portion of a blue LED, which is a micro LED display that extracts light color-converted by quantum dots from each subpixel.

[0035] The cured film obtained from the photosensitive resin composition of the present invention can form fine patterns, so it can be suitably used for micro LED displays.

[0036] The film and dry film formed of the photosensitive resin composition of the present invention can easily form fine patterns with excellent perpendicularity by the pattern forming method described later. In addition, the obtained cured film has favorable optical properties, chemical resistance and reliability, so it can be suitably used for display devices such as micro LED displays.

[0037] [Photosensitive resin composition] The photosensitive resin composition of the present invention comprises: (A) an acrylic resin having a (meth)acryloyl group in a side chain; (B1) a quantum dot; (B2) a thiol ligand coordinated to the surface of said quantum dot, wherein the thiol ligand comprises any one of poly(ethylene oxide), poly(propylene oxide) block copolymers, poly(ethylene oxide) block copolymers, or poly(propylene oxide) block copolymers; (C) a photoradical generator which is a carbazole-based oxime ester compound; (D) light-scattering particles having a refractive index of 1.90 or more and an average particle diameter of 100 to 400 nm; (E) a surfactant; and (F) a solvent. In addition to the respective components described above, component (G) described below and other additives may be included. Hereinafter, each component constituting the photosensitive resin composition of the present invention will be described.

[0038] [(A) Acrylic resin having a (meth)acryloyl group in a side chain] Component (A) contained in the present invention is not particularly limited as long as it is (A) an acrylic resin having a (meth)acryloyl group in a side chain. The above-mentioned acrylic resin means a polymer of an acrylic ester or a methacrylic ester.

[0039] For component (A) described above, the weight average molecular weight Mw of component (A) is preferably in the range of 10,000 to 50,000, and more preferably in the range of 15,000 to 45,000. When the weight average molecular weight of component (A) is within the above range, film reduction in exposed areas is less likely to occur during development, and the solubility of unexposed areas is favorable. The weight average molecular weight is a value determined as a polystyrene-equivalent weight average molecular weight (weight average degree of polymerization) by GPC (gel permeation chromatography) analysis using toluene as a developing solvent at a column temperature of 40°C.

[0040] For component (A) described above, the double bond equivalent is preferably 700 g / mol or less, and more preferably 600 g / mol or less. The double bond equivalent refers to the weight of the resin per one acrylic group. When the double bond equivalent of component (A) is within the above range, the crosslinking density is high, and a pattern with high sensitivity and favorable shape can be formed after development.

[0041] The above component (A) may be used alone or in combination of two or more types. Furthermore, component (A) is preferably present in an amount of 10 to 85% by mass in the nonvolatile components of the photosensitive resin composition. More preferably, it is 20 to 80% by mass.

[0042] [(B1) Quantum Dots] The (B1) quantum dots included in the present invention are semiconductor nanoparticles with an average particle diameter mainly between 1 nm and 100 nm, which, when energized from an external source and become airborne, autonomously release energy (emit light) through the corresponding energy band gap. The (B1) quantum dots are not particularly limited as long as they are of this type. The particle diameter of the (B1) quantum dots can be determined, for example, by dynamic light scattering using the ELSZ-2000ZS manufactured by Otsuka Electronics.

[0043] The above (B1) quantum dots have high responsiveness and can efficiently utilize light emitted from a light source. Furthermore, since their energy state depends on their size, the emission wavelength can be freely selected by changing the particle size. In addition, by combining light with a narrow spectral width and a steep peak of the emission wavelength, the displayable color gamut can be expanded in a display device equipped with a blue LED including a cured film formed from a photosensitive resin composition. For this reason, quantum dots that can be converted to red and green light are preferred.

[0044] The above (B1) quantum dot has a core-shell structure including a core and a shell covering the core, wherein the core preferably contains one or more compounds made up of any two or more combinations of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Ag, Hg, N, As, and O, and the shell preferably contains one or more compounds made up of any two or more combinations of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Hg, N, As, O, Mn, and Sr. Examples of such combinations include fine particles in which the core is InP or AgGaSe and the shell is ZnS, ZnSe, or ZnSeS.

[0045] The above (B1) quantum dots are preferably present in an amount of 10 to 50% by mass, more preferably 15 to 48% by mass, and even more preferably 20 to 45% by mass, in the nonvolatile components of the above photosensitive resin composition. If the content of quantum dot particles is within the above range, fine patterns can be formed while maintaining good luminescence characteristics.

[0046] [(B2) Thiol Ligand] The (B2) component included in the present invention is a thiol ligand coordinated to the surface of the quantum dot, and is a thiol ligand comprising any one of poly(ethylene oxide), poly(propylene oxide), poly(ethylene oxide) block copolymer, and poly(propylene oxide) block copolymer, and is not particularly limited as long as it is such a (B2) component.

[0047] Examples of the thiol ligands mentioned above include compounds represented by the following general formula (B2ex).

[0048] In the above general formula (B2ex), R １ R is a hydrogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated hydrocarbyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and n is an integer from 0 to 100. ２ n+m is a saturated hydrocarbylene group having 1 to 6 carbon atoms, and m is an integer from 0 to 100, where n+m>0. X is one of an ether bond, an ester bond, or an amide bond, and p is 0 or 1.

[0049] The above-mentioned (B2) thiol ligand is preferably present in an amount of 10 to 45 parts by mass, more preferably 15 to 40 parts by mass, and even more preferably 20 to 35 parts by mass, per 100 parts by mass of the (B1) quantum dot component. If the amount of thiol ligand added is within the above range, it will blend well with component (A), suppress the generation of aggregates, and form a highly sensitive pattern with a good shape.

[0050] [(C) Photoradical Generator which is a Carbazole Oxime Ester Compound] The (C) component included in the present invention is a photoradical generator which is a (C) carbazole oxime ester compound, and is not particularly limited as long as it is a carbazole oxime ester compound that improves sensitivity during lithography.

[0051] Examples of the above carbazole oxime compounds include N-acetoxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]ethane-1-imine, N-acetoxy-1-[9-ethyl-6-{2-methyl-4-(3,3-dimethyl-2,4-dioxacyclopentanylmethyloxy)benzoyl}-9H-carbazole-3-yl]ethane-1-imine, and N-acetoxy-1-[9-ethyl- Compounds such as 6-(2-methylbenzoyl)-9H-carbazole-3-yl]-3-cyclopentylpropan-1-imine and N-benzoyloxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-3-cyclopentylpropan-1-one-2-imine are examples, as are commercially available products such as ADEKA Arcules N-1919T (manufactured by ADEKA Corporation), NCI-831E (manufactured by ADEKA Corporation), Nikkacure IW-15 (Nippon Chemical Industries, Ltd.), Nikkacure YJ-04(T) (Nippon Chemical Industries, Ltd.), Nikkacure TG-05 (Nippon Chemical Industries, Ltd.), and Nikkacure TG-10 (Nippon Chemical Industries, Ltd.).

[0052] The above-mentioned component (C) preferably has a maximum absorption wavelength of 350 nm or more, and more preferably has a maximum absorption wavelength of 360 nm or more. Examples include NCI-831E (manufactured by ADEKA Corporation, maximum absorption wavelength 373 nm), Nikkacure IW-15 (manufactured by Nippon Chemical Industries, Ltd., maximum absorption wavelength 372 nm), and Nikkacure YJ-04(T) (manufactured by Nippon Chemical Industries, Ltd., maximum absorption wavelength 370 nm). If the maximum absorption wavelength of component (C) is within the above range, even if the light absorption by quantum dots during lithography exposure is large, radical species can be efficiently generated all the way to the bottom of the photosensitive resin composition, and a good pattern can be formed without development peeling. There is no particular upper limit to the maximum absorption wavelength of component (C), but it can be, for example, 430 nm or less.

[0053] The above-mentioned component (C) is preferably present in an amount of 0.1 to 1.5% by mass, and more preferably 0.1 to 1.0% by mass, in the non-volatile components of the above-mentioned photosensitive resin composition. If the content of component (C) is within the above range, fine patterns can be formed while maintaining good luminescence characteristics.

[0054] In other words, it is preferable that component (C) has a maximum absorption wavelength of 350 nm or more and is present in the non-volatile components of the photosensitive resin composition in an amount of 0.1 to 1.5% by mass.

[0055] [(D) Light-scattering particles] The light-scattering particles of component (D) included in the present invention are not particularly limited as long as they have a refractive index of 1.90 or higher and an average particle diameter of 100 to 400 nm. Preferably, they have a refractive index of 2.00 or higher and an average particle size of 150 to 350 nm. If the refractive index is less than 1.90, the refractive index difference with the substrate cannot be obtained, and the scattering effect of the irradiated light inside the film will be low. Also, if the average particle diameter is less than 100 nm, a sufficient scattering effect of the irradiated light inside the film cannot be obtained, and if the average particle diameter exceeds 400 nm, there is a risk of sedimentation in the composition. The method for measuring the particle diameter of the light-scattering particles is the laser diffraction particle size distribution measurement method. There is no particular upper limit to the refractive index of component (D), but for example it can be 3.0 or less, and more preferably 2.6 or less.

[0056] It is preferable that the surface of the light-scattering particles as component (D) included in the present invention is modified with aluminum hydroxide. A product with such modification has better compatibility with component (A), can suppress the generation of aggregates, and can form a pattern with high sensitivity and good shape.

[0057] Examples of the light-scattering particles include ZnO (refractive index: 2.10), ZrO ２ (refractive index: 2.05), BaTiO ３ (refractive index: 2.41), TiO ２ (refractive index: 2.35), TiO (refractive index: 2.35), Ti ３ O ５ (refractive index: 2.35), Ta ２ O ５ (refractive index: 2.10), Nb ２ O ３ (refractive index: 2.25), SnO (refractive index: 2.01), and combinations of these metal oxides.

[0058] Component (D) included in the present invention is preferably contained in an amount of 2 to 40% by mass, more preferably 3 to 30% by mass, based on the non-volatile components of the photosensitive resin composition. When the content of component (D) is within the above range, fine pattern formation can be performed while maintaining good light-emitting properties.

[0059] [(E) Surfactant] The surfactant as component (E) included in the present invention is not particularly limited as long as it can improve coating properties, and is preferably a silicone-based surfactant.

[0060] Examples of the above-mentioned silicone-based surfactants include surfactants having siloxane bonds in their molecules. Specifically, examples include Toray Silicone DC3PA, SH7PA, DC11PA, SH21PA, SH28PA, SH29PA, SH30PA, SH8400 (product name: manufactured by Toray Dow Corning Co., Ltd.), KP321, KP322, KP323, KP324, KP326, KP340, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF4446, TSF4452, and TSF4460 (manufactured by Momentive Performance Materials Japan LLC).

[0061] The surfactant (E) described above is preferably present in an amount of 0.001 to 0.7% by mass, and more preferably 0.005 to 0.5% by mass, in the nonvolatile components of the photosensitive resin composition. If the content of surfactant (E) is within the above range, a film with high flatness can be formed.

[0062] [(F) Solvent] The (F) solvent included in the present invention is not particularly limited as long as it can dissolve and disperse the components (A) to (E) described above and other various additives.

[0063] As the solvent (F) above, organic solvents are preferred, and examples include ketones such as cyclohexanone, cyclopentanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono-tert-butyl ether acetate, and γ-butyrolactone. These may be used individually or in combination of two or more.

[0064] As the solvent (F) above, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, cyclopentanone, and mixed solvents thereof are preferred, as they have particularly good dispersibility of (B1) quantum dots coordinated with (B2) thiol ligands and solubility of (A) acrylic resins having (meth)acryloyl groups.

[0065] From the viewpoint of compatibility and viscosity of the photosensitive resin composition, the content of component (F) is preferably 25 to 85% by mass, and more preferably 35 to 75% by mass, relative to the total amount of the photosensitive resin composition.

[0066] [(G) Polyfunctional (meth)acrylate] In addition to the components described above, the photosensitive resin composition of the present invention may further contain (G) polyfunctional (meth)acrylate. In this case, the double bond equivalent of the polyfunctional (meth)acrylate is preferably 300 g / mol or less, and if it is within the above range, the crosslinking density can be increased to form a pattern with a good shape after development. The lower limit of the double bond equivalent of the (G) polyfunctional (meth)acrylate is not particularly limited, but for example it can be 50 g / mol or more.

[0067] Examples of the above (G) polyfunctional (meth)acrylates include TMPTA, THEIC, PETA, PETTA, DTMP, and DPHA systems, such as dipentaerythritol hexaacrylate (DPHA), isocyanuric acid EO-modified di and triacrylates, Aronics M-940, and Aronics M-315 (manufactured by Toagosei Co., Ltd.).

[0068] [Other Additives] In addition to the components (A) to (G) described above, the photosensitive resin composition of the present invention may also contain other additives. Examples of other additives include silane coupling agents, which are used to improve development adhesion.

[0069] [Photosensitive resin coating] The photosensitive resin coating of the present invention is a dried body of the photosensitive resin composition described above.

[0070] [Pattern Forming Method Using Photosensitive Resin Composition] The pattern forming method using the photosensitive resin composition of the present invention includes the steps of (i) applying the photosensitive resin composition described above onto a substrate to form a photosensitive resin film on the substrate, (ii) exposing the photosensitive resin film to light, and (iii) developing the exposed photosensitive resin film with a developer solution to dissolve and remove the unexposed areas and form a pattern.

[0071] Step (i) is a step of applying the photosensitive resin composition described above onto a substrate to form a photosensitive resin film on the substrate. The photosensitive resin film is a dried body of the photosensitive resin composition. Examples of the substrate include silicon wafers, glass wafers, quartz wafers, plastic circuit boards, ceramic circuit boards, and the like.

[0072] The coating method can be any known method, such as the dip method, spin coating method, or roll coating method. The amount to be coated can be appropriately selected depending on the purpose, but it is preferable to coat the material so that the thickness of the resulting photosensitive resin film (dried photosensitive resin composition) is preferably 0.1 to 50 μm, more preferably 1 to 30 μm.

[0073] To ensure efficient photocuring, preheating (pre-baking) may be performed to evaporate solvents and other substances beforehand, if necessary. Pre-baking can be carried out, for example, at 60-120°C for 1 minute to 1 hour.

[0074] Next, (ii) the photosensitive resin film is exposed to light. The exposure is preferably carried out with light having a wavelength of 10 to 600 nm, and more preferably with light having a wavelength of 190 to 500 nm. Examples of such wavelengths include light of various wavelengths generated by a radiation generator, such as ultraviolet light (g-rays, h-rays, i-rays, etc.) and far-ultraviolet light (248 nm, 193 nm). Of these, light with a wavelength of 248 to 436 nm is particularly preferred. The exposure dose is 10 to 10,000 mJ / cm². ２ It is preferable.

[0075] Exposure may be performed via a photomask. The photomask may, for example, have a desired pattern cut out of it. The material of the photomask is not particularly limited, but it is preferably one that blocks light of the aforementioned wavelength. For example, one containing chromium as a light-shielding film is preferably used, but is not limited to this.

[0076] (iii) After exposure, the substrate is developed with a developer to form a pattern. Preferred developers include organic solvents such as alcohols such as IPA, ketones such as cyclohexanone, glycols such as propylene glycol monomethyl ether, and known alkaline developers such as aqueous solutions of tetramethylammonium hydroxide. Conventional development methods include the dipping method, in which the patterned substrate is immersed in the developer; the paddle method, in which the developer is dispensed with a paddle; and the spray method, in which the developer is applied with a spray. By developing in this way, the unexposed areas are dissolved and removed, and a pattern is formed. After that, washing, rinsing, drying, etc. are performed as necessary to obtain a cured film having the desired pattern.

[0077] [Photosensitive dry film] The photosensitive dry film of the present invention comprises a support film and a photosensitive resin coating obtained from a photosensitive resin composition on the support film.

[0078] The photosensitive dry film (support film and photosensitive resin coating) is solid, and since the photosensitive resin coating does not contain solvents, there is no risk of bubbles remaining between the photosensitive resin coating and the uneven substrate due to its volatilization. The thickness of the photosensitive resin coating is not particularly limited, but is preferably 1 to 100 μm, and more preferably 3 to 50 μm.

[0079] Furthermore, the viscosity and fluidity of the photosensitive resin film are closely related, and if the photosensitive resin film has an appropriate viscosity range, it can exhibit appropriate fluidity. In other words, with an appropriate viscosity, it can penetrate into narrow gaps to improve adhesion, and the softening of the resin can improve adhesion to the substrate. Therefore, from the viewpoint of the fluidity of the photosensitive resin film, the viscosity of the photosensitive resin film is preferably 10 to 5,000 Pa·s, more preferably 30 to 2,000 Pa·s, at 80 to 120°C. In this invention, viscosity is measured using a rotational viscometer.

[0080] When the photosensitive dry film of the present invention is adhered to an uneven substrate, the photosensitive resin coating conforms to the unevenness, achieving high flatness. In particular, the photosensitive resin composition of the present invention is characterized by its softening properties, which enables even higher flatness to be achieved. Furthermore, when the photosensitive resin coating is adhered to the substrate in a vacuum environment, the occurrence of gaps can be prevented more effectively.

[0081] The photosensitive dry film of the present invention can be manufactured by applying the photosensitive resin composition onto a substrate and drying it to form a photosensitive resin film. A film coater for manufacturing adhesive products can generally be used as the manufacturing apparatus for the photosensitive dry film. Examples of film coaters include comma coaters, comma reverse coaters, multi coaters, die coaters, lip coaters, lip reverse coaters, direct gravure coaters, offset gravure coaters, three-bottom reverse coaters, four-bottom reverse coaters, and the like.

[0082] A photosensitive dry film can be manufactured by unwinding a support film from the unwinding shaft of the film coater and passing it through the coater head of the film coater, applying the photosensitive resin composition to the support film to a predetermined thickness, then passing it through a hot air circulation oven at a predetermined temperature and time to dry it on the support film and form a photosensitive resin coating. Alternatively, if necessary, a photosensitive dry film with a protective film can be manufactured by passing the photosensitive dry film together with a protective film unwinding from another unwinding shaft of the film coater through a laminating roll at a predetermined pressure to bond the photosensitive resin coating on the support film with the protective film, and then winding it onto the winding shaft of the film coater. In this case, the temperature is preferably 50 to 120°C, the time is preferably 1 to 100 minutes, and the pressure is preferably 0.01 to 5 MPa.

[0083] The support film used in the photosensitive dry film of the present invention may be a single-layer film consisting of a single film, or a multilayer film formed by laminating multiple films. Examples of materials for the film include synthetic resin films such as polyethylene, polypropylene, polycarbonate, and polyethylene terephthalate. Of these, polyethylene terephthalate, which has appropriate flexibility, mechanical strength, and heat resistance, is preferred. These films may have undergone various treatments such as corona treatment or coating with a release agent. Commercially available products can be used, such as Therapiel WZ (RX), Therapiel BX8 (R) (both manufactured by Toray Film Processing Co., Ltd.), E7302, E7304 (both manufactured by Toyobo Co., Ltd.), Purex G31, Purex G71T1 (both manufactured by Teijin DuPont Films Ltd.), PET38×1-A3, PET38×1-V8, PET38×1-X08 (all manufactured by Nippa Co., Ltd.).

[0084] The protective film can be the same as the support film described above, but polyethylene terephthalate and polyethylene, which have appropriate flexibility, are preferred. Commercially available products can be used, and examples of polyethylene terephthalate include those already exemplified, while examples of polyethylene include GF-8 (manufactured by Tamapoly Co., Ltd.) and PE film type 0 (manufactured by Nipper Co., Ltd.).

[0085] The thickness of the support film and protective film is preferably 10 to 100 μm, more preferably 25 to 50 μm, from the viewpoint of stability in the production of the photosensitive dry film and prevention of curling on the core.

[0086] [Pattern Forming Method Using Photosensitive Dry Film] The pattern forming method using a photosensitive dry film of the present invention includes: (i') a step of attaching the photosensitive resin film of the photosensitive dry film described above to a substrate to form the photosensitive resin film on the substrate; (ii) a step of exposing the photosensitive resin film to light; and (iii) a step of developing the exposed photosensitive resin film with a developer solution to dissolve and remove the unexposed areas to form a pattern.

[0087] Step (i') is the step of attaching the photosensitive resin coating of the photosensitive dry film to a substrate to form a photosensitive resin coating on the substrate. In other words, a photosensitive resin coating is formed on the substrate by attaching the photosensitive resin coating of the photosensitive dry film to the substrate. If the photosensitive dry film has a protective film, the protective film is peeled off from the photosensitive dry film before attaching the photosensitive resin coating of the photosensitive dry film to the substrate. The attachment can be performed, for example, using a film attachment device.

[0088] A vacuum laminator is preferred as the film application device. For example, the protective film of the photosensitive dry film is peeled off, and the exposed photosensitive resin film is pressed onto the substrate on a table at a predetermined temperature using an application roll at a predetermined pressure in a vacuum chamber with a predetermined vacuum level. The temperature is preferably 60 to 120°C, the pressure is preferably 0 to 5.0 MPa, and the vacuum level is preferably 50 to 500 Pa.

[0089] To efficiently carry out the photocuring reaction of the photosensitive resin film and to improve the adhesion between the photosensitive resin film and the substrate, pre-baking may be performed as needed. Pre-baking can be performed, for example, at 60 to 120°C for about 1 minute to 1 hour.

[0090] The photosensitive resin film attached to the substrate can be formed by (ii) exposing the photosensitive resin film to light, (iii) developing it with a developer, dissolving and removing the unexposed areas, and forming a pattern, similar to the pattern formation method using the photosensitive resin composition. It is preferable to remove the support film of the photosensitive dry film before the development step, depending on the process.

[0091] The photosensitive resin composition and dry film pattern formation method of the present invention facilitate the formation of fine patterns. For example, by forming a film of the photosensitive resin composition of the present invention to cover a large number of blue micro-LEDs arranged on a substrate, and then performing fine pattern formation, a cured film containing red and green quantum dots in different parts is formed on the blue micro-LEDs, thereby generating red and green light emission, making it possible to manufacture a full-color display device.

[0092] [Display Device] The display device of the present invention comprises a cured film in which the photosensitive resin composition described above is patterned.

[0093] Furthermore, the display device of the present invention is equipped with a patterned cured film of the photosensitive resin composition described above on top of a blue LED, and extracts light color-converted by quantum dots from each subpixel.

[0094] [Micro LED Display] The micro LED display of the present invention is a 0.01 mm patterned photosensitive resin composition as described above. ２ The following cured coating is provided on top of the blue LED, and the light color-converted by quantum dots is extracted from each subpixel. There is no particular lower limit to the area of ​​the cured coating, but for example, 2.5 × 10⁻⁶ －５ mm ２ This can be done.

[0095] The present invention will be described more specifically below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0096] [1] Preparation and evaluation of photosensitive resin compositions [Examples R1-6, G1-6 and Comparative Examples R'1-13, G'1-13] Each component was blended according to the amounts listed in Tables 1-4, and then stirred and mixed at room temperature to obtain the photosensitive resin compositions of Examples R1-6, G1-6 and Comparative Examples R'1-13, G'1-13. After standing for 24 hours, those in which no sedimentation or bilayer separation was observed were marked with ○, and those in which it was observed were marked with ×. The results are shown in Tables 7-10. The numbers of the examples and comparative examples are organized by adding R to those containing red-emitting quantum dots in component (B1) and G to those containing green-emitting quantum dots.

[0097]

[0098]

[0099]

[0100]

[0101] In Tables 1 to 4, A-1 to A-2 and A'-1 use the resins listed in Table 5. The acid values ​​listed in Table 5 were calculated according to the method in accordance with JIS 0070-1992, and the double bond equivalent was calculated using the formula: double bond equivalent = molecular weight / number of functional groups (number of double bonds).

[0102]

[0103] In Tables 1-4, B1-1R is an InP / ZnSe core-shell quantum dot with a maximum fluorescence wavelength of 629 nm (red emission), B1-1G is an InP / ZnSe core-shell quantum dot with a maximum fluorescence wavelength of 521 nm (green emission), B1-2R is an AgGaSe / ZnS core-shell quantum dot with a maximum fluorescence wavelength of 631 nm (red emission), and B1-2G is an AgGaSe / ZnS core-shell quantum dot with a maximum fluorescence wavelength of 530 nm (green emission).

[0104] In Tables 1 to 4, B1'-1R is "R-3 in the example of Patent Document 1 (InP / ZnSe core-shell quantum dot with a maximum fluorescence wavelength of 629 nm coated with a copolymer of alkoxysilane or alkoxysilane hydrolysate condensate (red emission))", B1'-1G is "G-3 in the example of Patent Document 1 (InP / ZnSe core-shell quantum dot with a maximum fluorescence wavelength of 521 nm coated with a copolymer of alkoxysilane or alkoxysilane hydrolysate condensate (green emission))", B1'-2R is "R-4 in the example of Patent Document 1 (InP / ZnSe core-shell quantum dot with a maximum fluorescence wavelength of 629 nm coated with a copolymer of alkoxysilane or alkoxysilane hydrolysate (red emission))", and B1'-2G is "G-4 in the example of Patent Document 1 (InP / ZnSe core-shell quantum dot with a maximum fluorescence wavelength of 521 nm coated with a copolymer of alkoxysilane or alkoxysilane hydrolysate (green emission))".

[0105] In Tables 1 to 4, B2-1 and B2-2 are as shown in the following structural formulas, where B2'-1 is oleic acid and B2'-2 is dodecanethiol.

[0106] In Tables 1-4, C-1 is the product name "NCI-831E" (carbazole oxime ester, maximum absorption wavelength 373 nm) manufactured by ADEKA Corporation, C-2 is the product name "Nikkacure IW-15" (carbazole oxime ester, maximum absorption wavelength 372 nm) manufactured by Nippon Chemical Industries, Ltd., C'-1 is the product name "PBG-305" (phenyl sulfide oxime ester, maximum absorption wavelength 328 nm) manufactured by TRONLY, and C'-2 is the product name "Irgacure 819" (acylphosphine oxide, maximum absorption wavelength 380 nm) manufactured by BASF.

[0107] In Tables 1-4, D-1 to D-3 and D'-1 to D'-5 are those listed in Table 6. For the refractive index measurements listed in Table 6, the minimum deviation method was used, and the measuring device was a Shimadzu GM-1D model.

[0108]

[0109] In Tables 1-4, E-1 is the product name "KP341" (silicone-based surfactant) manufactured by Shin-Etsu Chemical Co., Ltd.

[0110] In Tables 1-4, F represents PGMEA (propylene glycol monomethyl ether acetate).

[0111] In Tables 1-4, G-1 is the product name "Arronix M-940" (polyfunctional acrylate) manufactured by Toagosei Co., Ltd., and G-2 is the product name "Arronix M-315" (polyfunctional acrylate) manufactured by Toagosei Co., Ltd.

[0112] [2] Preparation of Photosensitive Dry Film A die coater was used as the film coater and polyethylene terephthalate film (38 μm thick) as the support film. The photosensitive resin compositions described in Tables 1 to 4 were applied to the support film. Next, the films were dried by passing them through a hot air circulation oven (4 m long) set to 80°C for 5 minutes to form a photosensitive resin film with a thickness of 10 μm on the support film, thereby obtaining a photosensitive dry film. A polyethylene film (50 μm thick) was laminated onto the photosensitive resin film as a protective film using a laminating roll at a pressure of 1 MPa to prepare a photosensitive dry film with a protective film. When peeling off the protective film from the prepared dry film, any area where the photosensitive resin film adhered to the protective film and peeled off from the base film was marked with ×, and any area where there were no problems was marked with ○. The results, along with the viscosity measurement results, are shown in Tables 7 to 10.

[0113] [3] Pattern Formation and Evaluation The protective film was peeled off from the photosensitive dry film with protective film as described in [2], and the vacuum in the vacuum chamber was set to 80 Pa using a vacuum laminator TEAM-100RF (manufactured by Takatori Co., Ltd.) to press the photosensitive resin film on the support film against the silicon wafer. The temperature was set to 100°C. After returning to atmospheric pressure, the substrate was removed from the vacuum laminator and the support film was peeled off. Next, to improve adhesion to the substrate, pre-baking was performed on a hot plate at 100°C for 2 minutes. To form a square island pattern with a pitch width of 1:1 between adjacent patterns via a mask on the obtained photosensitive resin film, exposure was performed using a contact aligner type exposure apparatus (Mask Aligner MA8 from Suss Microtec) at an exposure condition of 405 nm. After irradiation, patterns were formed by paddle development for 90 seconds using propylene glycol monomethyl ether for R1, R3, R5, R'2, R'3, R'9, R'11, R'13, and G1, G3, G5, G'2, G'3, G'9, G'11, and G'13, and with a 2.38% aqueous solution of tetramethylammonium hydroxide for the others. Subsequently, island patterns with sides of 50 μm, 20 μm, 10 μm, 5 μm, and 3 μm were observed using a scanning electron microscope (SEM), and the smallest pattern size that was not connected to an adjacent island pattern (pitch width of 1:1) was defined as the limiting resolution. The perpendicularity of the patterns was also evaluated, with vertical patterns (80° ≤ taper angle ≤ 100°) being marked as ○, and tapered shapes (80° > taper angle, 100° < taper angle) or poor aperture being marked as ×. The results are shown in Tables 7-10. Furthermore, patterns showing aggregates larger than 1 μm were marked with ×, and those without aggregates were marked with ○. The results are shown in Tables 7 to 10.

[0114] [4] Change rate of optical properties after luminescence characteristics and chemical resistance tests An island pattern with sides of 5 cm was formed on a glass wafer as the substrate in the same manner as in [3] above. Spectroscopic radiation measurements were performed from the film side using a UPRtek MK350S PREMIUM while irradiating the glass surface with a 4 mW blue LED. At this time, the radiation amount corresponding to blue in the 440-480 nm range was designated as [Sample-B], the radiation amount corresponding to green in the 500-560 nm range for Examples G1-6 and Comparative Examples G'1-13 was designated as [Sample-G], and the radiation amount corresponding to red in the 600-660 nm range for Examples R1-6 and Comparative Examples R'1-13 was designated as [Sample-R]. In addition, the radiation amount corresponding to blue in the 440-480 nm range when measured on a glass wafer only was designated as [Reference-B] as a reference. The luminescence characteristics for Examples G1 to 6 and Comparative Examples G'1 to 13 were calculated using ([Sample-G] / ([Reference-B] - [Sample-B]) × 100), and for Examples R1 to 6 and Comparative Examples R'1 to 13, they were calculated using ([Sample-R] / ([Reference-B] - [Sample-B]) × 100). The results are shown in Tables 7 to 10. The maximum fluorescence wavelength and full width at half maximum in the 500 to 560 nm range for Examples G1 to 6 and Comparative Examples G'1 to 13, and the peak wavelength and full width at half maximum for Examples R1 to 6 and Comparative Examples R'1 to 13 are also shown in Tables 7 to 10. Furthermore, the samples were immersed for one hour in a solution consisting of 40 parts by weight of monoethanolamine, 30 parts by weight of N,N-dimethylacetamide, and 30 parts by weight of carbitol, and measurements were taken again to confirm the rate of change in luminescence characteristics and irradiation light transmittance [Sample-B] (rate of change in irradiation light intensity) before and after the chemical resistance test. The results are shown in Tables 7 to 10.

[0115] [5] Change rate of luminescence characteristics after high-temperature test Substrates prepared by the same method as in [4] above were treated at 150°C for 300 hours instead of acetone immersion, and measurements were taken again to confirm the change rate of luminescence characteristics before and after the high-temperature test. The results are shown in Tables 7 to 10.

[0116] [6] As an evaluation substrate for adhesion testing after high-temperature testing, a wafer with a Cu seed layer on its surface was used to form an island pattern with sides of 5 cm in the same manner as in [4] above. After processing at 150°C for 300 hours, a grid peel test (JIS K 5400) was performed to evaluate the adhesion to the substrate. The number of peels observed per 100 grid points is shown in Tables 7 to 10 as a result.

[0117]

[0118]

[0119]

[0120]

[0121] The results above demonstrate that the photosensitive resin composition of the present invention shows no abnormalities in the varnish even after standing, can form good photosensitive coatings and photosensitive dry films, has high rectangularity and resolution lithography performance, is free of aggregates in the formed pattern, the formed pattern has high luminescence properties, does not change optical properties after chemical resistance tests and reliability tests (high temperature tests), and has high adhesion, thus providing a material suitable for display devices (especially micro-LED displays).

[0122] On the other hand, in Comparative Examples R'1 and G'1, which differ from the present invention in component (A), Comparative Examples R'2,3 and G'2,3, which differ in component (C), Comparative Examples R'4 to 8 and G'4 to 8, which differ in component (D), Comparative Examples R'9,10 and G'9,10, which differ in component (B2), Comparative Examples R'11,12 and G'11,12, which do not contain component (B2), and Comparative Examples R'13 and G'13, which do not contain component (D), some showed good varnish after standing, but in all comparative examples, it was not possible to form a photosensitive coating or a photosensitive dry film, and a cured film with high rectangularity and resolution could not be formed. Aggregates were observed in the formed patterns, and the optical properties deteriorated after chemical resistance tests and high-temperature tests, so a cured coating suitable for use as a display device could not be obtained.

[0123] This specification includes the following embodiments: [1]: A photosensitive resin composition comprising: (A) an acrylic resin having (meth)acryloyl groups in its side chains; (B1) quantum dots; (B2) a thiol ligand coordinated to the surface of the quantum dots, comprising one of poly(ethylene oxide), poly(propylene oxide), poly(ethylene oxide) block copolymer, and poly(propylene oxide) block copolymer; (C) a photoradical generator which is a carbazole oxime ester compound; (D) light scattering particles having a refractive index of 1.90 or higher and an average particle diameter of 100 to 400 nm; (E) a surfactant; and (F) a solvent. [2]: The photosensitive resin composition according to [1], characterized in that the surface of the light scattering particles of component (D) is modified with aluminum hydroxide. [3]: The photosensitive resin composition according to [1] or [2] above, characterized in that the (D) component is contained in the nonvolatile components of the photosensitive resin composition in an amount of 2 to 40% by mass. [4]: ​​The photosensitive resin composition according to any one of [1] to [3] above, characterized in that the (B1) component has a core-shell structure including a core and a shell covering the core, the core contains one or more compounds consisting of a combination of two or more of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Ag, Hg, N, As, and O, and the shell contains one or more compounds consisting of a combination of two or more of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Hg, N, As, O, Mn, and Sr. [5]: The photosensitive resin composition according to any one of [1] to [4] above, characterized in that the (B1) component is contained in 10 to 50% by mass in the nonvolatile components of the photosensitive resin composition. [6]: The photosensitive resin composition according to any one of [1] to [5] above, characterized in that the (B2) component is contained in 10 to 45 parts by mass per 100 parts by mass of the (B1) component.[7]: The photosensitive resin composition according to any one of [1] to [6] above, characterized in that the (C) component has a maximum absorption wavelength of 350 nm or more and is contained in the nonvolatile components of the photosensitive resin composition in an amount of 0.1 to 1.5% by mass. [8]: The photosensitive resin composition according to any one of [1] to [7] above, further characterized in that it contains (G) a polyfunctional (meth)acrylate having a double bond equivalent of 300 g / mol or less. [9]: A photosensitive resin film characterized in that it is a dried body of the photosensitive resin composition according to any one of [1] to [8] above.

[10] : A photosensitive dry film characterized in that it comprises a support film and the photosensitive resin film according to [9] above on the support film.

[11] : A pattern forming method comprising: (i) applying a photosensitive resin composition according to any one of the above items [1] to [8] onto a substrate to form a photosensitive resin film on the substrate; (ii) exposing the photosensitive resin film to light; and (iii) developing the exposed photosensitive resin film with a developer solution to dissolve and remove the unexposed areas and form a pattern.

[12] A pattern forming method comprising: (i') attaching the photosensitive resin film of the photosensitive dry film according to the above item

[10] onto a substrate to form a photosensitive resin film on the substrate; (ii) exposing the photosensitive resin film to light; and (iii) developing the exposed photosensitive resin film with a developer solution to dissolve and remove the unexposed areas and form a pattern.

[13] : A display device characterized by comprising a cured film in which the photosensitive resin composition described in any one of the above items [1] to [8] is patterned.

[14] : A display device characterized by comprising a cured film in which the photosensitive resin composition described in any one of the above items [1] to [8] is patterned on the top of a blue LED, and extracting light color-converted by quantum dots from each subpixel.

[15] : A 0.01 mm patterned film in which the photosensitive resin composition described in any one of the above items [1] to [8] is patterned. ２A micro-LED display characterized by having the following cured coating on top of a blue LED, and extracting light color-converted by quantum dots from each subpixel.

[0124] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. A photosensitive resin composition comprising: (A) an acrylic resin having (meth)acryloyl groups in its side chains; (B1) quantum dots; (B2) a thiol ligand coordinated to the surface of the quantum dots, comprising one of poly(ethylene oxide), poly(propylene oxide), poly(ethylene oxide) block copolymer, and poly(propylene oxide) block copolymer; (C) a photoradical generator which is a carbazole oxime ester compound; (D) light scattering particles having a refractive index of 1.90 or higher and an average particle diameter of 100 to 400 nm; (E) a surfactant; and (F) a solvent.

2. The photosensitive resin composition according to claim 1, characterized in that the surface of the light scattering particles of component (D) is modified with aluminum hydroxide.

3. The photosensitive resin composition according to claim 1, characterized in that the (D) component is contained in the nonvolatile components of the photosensitive resin composition in an amount of 2 to 40% by mass.

4. The photosensitive resin composition according to claim 1, characterized in that the (B1) component has a core-shell structure including a core and a shell covering the core, the core contains one or more compounds consisting of a combination of two or more of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Ag, Hg, N, As, and O, and the shell contains one or more compounds consisting of a combination of two or more of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Hg, N, As, O, Mn, and Sr.

5. The photosensitive resin composition according to claim 1, characterized in that the (B1) component is contained in 10 to 50% by mass of the nonvolatile components of the photosensitive resin composition.

6. The photosensitive resin composition according to claim 1, characterized in that it contains 10 to 45 parts by mass of component (B2) with respect to 100 parts by mass of component (B1).

7. The photosensitive resin composition according to claim 1, characterized in that the component (C) has a maximum absorption wavelength of 350 nm or more and is contained in the nonvolatile components of the photosensitive resin composition in an amount of 0.1 to 1.5% by mass.

8. The photosensitive resin composition according to claim 1, further characterized in that it contains (G) a polyfunctional (meth)acrylate having a double bond equivalent of 300 g / mol or less.

9. A photosensitive resin film characterized by being a dried body of the photosensitive resin composition described in any one of claims 1 to 8.

10. A photosensitive dry film comprising a support film and a photosensitive resin coating according to claim 9 on the support film.

11. A pattern forming method comprising: (i) a step of applying a photosensitive resin composition according to any one of claims 1 to 8 onto a substrate to form a photosensitive resin film on the substrate; (ii) a step of exposing the photosensitive resin film to light; and (iii) a step of developing the exposed photosensitive resin film with a developer solution to dissolve and remove the unexposed areas to form a pattern.

12. A pattern forming method comprising: (i') a step of attaching the photosensitive resin film of the photosensitive dry film described in claim 10 to a substrate to form the photosensitive resin film on the substrate; (ii) a step of exposing the photosensitive resin film to light; and (iii) a step of developing the exposed photosensitive resin film with a developer solution to dissolve and remove the unexposed areas to form a pattern.

13. A display device characterized in that the photosensitive resin composition according to any one of claims 1 to 8 comprises a patterned cured film.

14. A display device characterized in that a patterned cured film of the photosensitive resin composition according to any one of claims 1 to 8 is provided on top of a blue LED, and light converted in color by quantum dots is extracted from each subpixel.

15. A 0.01 mm patterned photosensitive resin composition according to any one of claims 1 to 8. ２ A microLED display characterized by having the following cured coating on top of a blue LED, and extracting light color-converted by quantum dots from each subpixel.

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