Photosensitive resin composition, photosensitive resin film, photosensitive dry film, pattern forming method, display device, and micro-led display

Abstract

To provide a photosensitive resin composition enabling easy formation of a film exhibiting high lithography resolution and favorable light-emitting characteristics, a photosensitive resin film obtained from the photosensitive resin composition, a photosensitive dry film, a pattern forming method using the same, and a display device produced using the photosensitive resin composition.SOLUTION: A composition comprising (A) an acrylic resin having a (meth)acryloyl group in a side chain, (B1) quantum dots, (B2) a thiol ligand coordinated to surfaces of the component (B1), the thiol ligand having a polymer structure containing at least one repeating unit selected from ethylene oxide and propylene oxide, (C) an oxime-based photoradical generator, (D) a surfactant, and (E) a solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photosensitive resin composition, a photosensitive resin film, a photosensitive dry film, a pattern forming method, a display device, and a micro LED display. [Background technology]

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

[0003] In recent years, LED arrays have become micro-sized, and micro LED displays using these arrays have attracted attention. One method for forming a color conversion structure on an LED array is a lithography process using a photosensitive material (Patent Document 1), but in recent years, further miniaturization has been required for application to small displays. In addition, there are high demands for light-emitting characteristics in terms of display clarity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-089347 Summary of the Invention [Problem to be solved by the invention]

[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 and good light-emitting properties, a photosensitive resin film and a photosensitive dry film obtained using the photosensitive resin composition, a pattern formation method using these, and a display device obtained using the photosensitive resin composition. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides: (A) an acrylic resin having a (meth)acryloyl group in a side chain; (B1) quantum dots, (B2) a thiol ligand coordinated to the surface of the component (B1), the thiol ligand having a polymer structure containing at least one repeating unit selected from ethylene oxide and propylene oxide; (C) an oxime-based photoradical generator, (D) a surfactant, and (E) Solvent The present invention provides a photosensitive resin composition comprising:

[0007] Such a photosensitive resin composition can easily form a film having high lithography resolution and good light-emitting properties.

[0008] The component (A) is preferably an alkali-insoluble resin having a weight average molecular weight Mw of 10,000 to 50,000, a double bond equivalent of ≦300 g / mol, and an acid value of ≦10 mgKOH / g.

[0009] If the weight average molecular weight of the (A) acrylic resin having a (meth)acryloyl group in the side chain is within the above range, the film thickness of the exposed area is less likely to decrease during development, and the solubility of the unexposed area is good.

[0010] Furthermore, it is preferable that the component (B1) has a core-shell structure comprising a core and a shell covering the core, the core comprising one or more compounds formed by 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 comprising one or more compounds formed by a combination of two or more of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Hg, N, As, O, Mn, and Sr.

[0011] Such quantum dots can be suitably used.

[0012] The photosensitive resin composition preferably contains the component (B1) in an amount of 10 to 50% by mass of the nonvolatile components.

[0013] If the content of quantum dot particles is within the above range, fine patterns can be formed while maintaining good light-emitting properties.

[0014] It is also preferable that the component (B2) is contained in an amount of 5 to 45 parts by mass per 100 parts by mass of the component (B1).

[0015] When the amount of thiol ligand added is within the above range, it has good compatibility with the acrylic resin (A) having a (meth)acryloyl group in the side chain, making it possible to suppress the generation of aggregates and form patterns with high sensitivity and good shape.

[0016] The photosensitive resin composition preferably contains the component (C) in an amount of 0.1 to 1.5% by mass of the nonvolatile components.

[0017] If the content of the oxime-based photoradical generator is within the above range, fine patterns can be formed while maintaining good light-emitting properties.

[0018] The present invention also provides a photosensitive resin film which is a dried product of the above photosensitive resin composition.

[0019] The photosensitive resin film of the present invention can be used to produce a photosensitive dry film.

[0020] The present invention also provides a photosensitive dry film comprising a support film and the above-described photosensitive resin film formed on the support film.

[0021] The photosensitive dry film of the present invention can easily form a coating having high lithography resolution and good light-emitting properties.

[0022] In addition, in the present invention, A pattern formation method, comprising: (i) applying the 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) A step of developing the exposed photosensitive resin film with a developer to dissolve and remove the unexposed areas to form a pattern. The present invention provides a pattern formation method comprising the steps of:

[0023] The photosensitive resin composition of the present invention can be used to form a pattern of a desired shape.

[0024] In this case, it is preferable not to perform post-baking after the step (ii).

[0025] In this way, the (B1) quantum dots are not subjected to unnecessary heat history, and the cured film has high light-emitting properties.

[0026] In addition, in the present invention, A pattern formation method, comprising: (i') a step of attaching the photosensitive resin film of the photosensitive dry film to a substrate to form the photosensitive resin film on the substrate; (ii') exposing the photosensitive resin film to light; and (iii') A step of developing the exposed photosensitive resin film with a developer to dissolve and remove the unexposed areas to form a pattern. The present invention provides a pattern formation method comprising the steps of:

[0027] The photosensitive dry film of the present invention can be used to form a pattern of a desired shape.

[0028] In this case, it is preferable not to perform post-baking after the step (ii').

[0029] In this way, the (B1) quantum dots are not subjected to unnecessary heat history, and the cured film has high light-emitting properties.

[0030] The present invention also provides a display device having a pattern made of a cured film of the above photosensitive resin composition.

[0031] The photosensitive resin composition of the present invention can be particularly suitably used for such applications.

[0032] The present invention also provides a display device that has a pattern made of a cured film of the above-mentioned photosensitive resin composition above a blue LED, and extracts light color-converted by quantum dots from each subpixel.

[0033] The photosensitive resin composition of the present invention can be particularly suitably used for such applications.

[0034] In the present invention, a pattern made of a cured film of the above-mentioned photosensitive resin composition is provided above a blue LED, and the size of the pattern made of the cured film is 0.01 mm. 2 The present invention provides a micro LED display that extracts light color-converted by quantum dots from each sub-pixel.

[0035] The photosensitive resin composition of the present invention can be particularly suitably used for such applications. [Effects of the Invention]

[0036] The photosensitive resin composition of the present invention can be used to easily form fine, vertically aligned patterns using the patterning method of the present invention. The resulting cured film has high lithography resolution and excellent light-emitting properties, making it suitable for use in display devices such as micro LED displays. DETAILED DESCRIPTION OF THE INVENTION

[0037] As described above, there has been a demand for the development of a photosensitive resin composition that can easily form a film having high lithography resolution and good light-emitting properties, a photosensitive resin film and a photosensitive dry film obtained using the photosensitive resin composition, a pattern formation method using these, and a display device obtained using the photosensitive resin composition.

[0038] As a result of extensive research into achieving the above object, the present inventors have found that the above object can be achieved by a photosensitive resin composition containing specific components, and have thus completed the present invention.

[0039] That is, the present invention provides a photosensitive resin composition comprising: (A) an acrylic resin having a (meth)acryloyl group in a side chain; (B1) quantum dots; (B2) a thiol ligand coordinated to the surface of the component (B1), the thiol ligand having a polymer structure containing at least one repeating unit selected from ethylene oxide and propylene oxide; (C) an oxime-based photoradical generator; (D) a surfactant; and (E) a solvent.

[0040] The present invention will be described in detail below, but the present invention is not limited thereto.

[0041] [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) quantum dots, (B2) a thiol ligand coordinated to the surface of the component (B1), the thiol ligand having a polymer structure containing at least one repeating unit selected from ethylene oxide and propylene oxide, (C) an oxime-based photoradical generator, (D) a surfactant, and (E) a solvent.

[0042] [(A) Acrylic resin having a (meth)acryloyl group in the side chain] The acrylic resin (acrylic acid ester or methacrylic acid ester polymer) (A) having a (meth)acryloyl group on the side chain used in the present invention is not particularly limited.

[0043] In the present invention, the weight-average molecular weight Mw of the (A) acrylic resin having a (meth)acryloyl group on the side chain is preferably in the range of 10,000 to 50,000, more preferably 15,000 to 40,000. When the weight-average molecular weight Mw of the (A) acrylic resin having a (meth)acryloyl group on the side chain is within this range, film thickness reduction in the exposed area is unlikely to occur during development, and the solubility of the unexposed area in organic solvents is good. The weight-average molecular weight is a value determined as a weight-average molecular weight (weight-average degree of polymerization) converted into polystyrene by GPC (gel permeation chromatography) analysis using toluene as a developing solvent.

[0044] In the present invention, the acrylic resin (A) having a (meth)acryloyl group in its side chain preferably has a double bond equivalent in the range of ≦300 g / mol, more preferably ≦280 g / mol. The double bond equivalent is the weight of the resin per acrylic group. When the double bond equivalent of the acrylic resin (A) having a (meth)acryloyl group in its side chain falls within the above range, it is possible to form a pattern with a high crosslink density, high sensitivity, and good shape after development. Furthermore, the increased polarity of the side chain improves compatibility with the quantum dots (B1) coordinated with the ligands (B2), thereby suppressing the formation of aggregates.

[0045] In the present invention, the (A) acrylic resin having a (meth)acryloyl group in a side chain is preferably an alkali-insoluble resin having an acid value of ≦10 mgKOH / g. When the alkali-insoluble resin has an acid value of ≦10 mgKOH / g, the stability of the (B1) quantum dots coordinated with the (B2) ligand in the cured film is improved. Furthermore, since the resin contains almost no acid groups, post-baking to destroy these acid groups is not required, and therefore the (B1) quantum dots are not subjected to unnecessary thermal history, resulting in high light-emitting properties of the cured film.

[0046] In the present invention, the (A) acrylic resin having a (meth)acryloyl group on the side chain may be used alone or in combination of two or more. The (A) acrylic resin having a (meth)acryloyl group on the side chain preferably accounts for 10 to 85% by mass, more preferably 20 to 80% by mass, of the non-volatile components of the photosensitive resin composition.

[0047] (A) Examples of acrylic resins having a (meth)acryloyl group in the side chain include those manufactured by Negami Chemical Industries Co., Ltd. under the trade name "RA-3631P" and those manufactured by Taisei Fine Chemical Co., Ltd. under the trade name "8KQ-7060".

[0048] [(B1) Quantum dots] The (B1) quantum dots used in the present invention are semiconductor fine particles having a particle diameter of 1 nm to 100 nm, which, when exposed to external energy and raised to a floating state, autonomously (autonomously) emit energy (emit light) due to the corresponding energy band gap, and 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 an ELSZ-2000ZS manufactured by Otsuka Electronics.

[0049] (B1) Quantum dots have high responsiveness and can efficiently utilize light emitted from a light source. Furthermore, because their energy state depends on their size, it is possible to freely select the emission wavelength by changing the particle diameter. Furthermore, the emitted light has a narrow spectral width. By combining light with such a sharp peak, the displayable color gamut can be expanded in a display device equipped with a blue LED containing a cured film formed from a photosensitive resin composition. Therefore, quantum dots that can convert light into red and green light are preferred.

[0050] The quantum dots (B1) used in the present invention preferably have a core-shell structure comprising a core and a shell covering the core. The core preferably 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 preferably 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. Examples of such combinations include fine particles having a core of InP or AgGaSe and a shell of ZnS, ZnSe, or ZnSeS. Preferred core-shell combinations include core / shell = InP / ZnS, InP / ZnSe, InP / ZnSeS, and AgGaSe / ZnS.

[0051] The quantum dots (B1) used in the present invention preferably account for 10 to 50% by mass, more preferably 15 to 45% by mass, and even more preferably 20 to 40% by mass of the non-volatile components of the photosensitive resin composition. If the content of the quantum dot particles is within the above range, fine patterns can be formed while maintaining good light-emitting properties.

[0052] [(B2) Thiol Ligand] The thiol ligand (B2) coordinated on the surface of the quantum dots used in the present invention is not particularly limited as long as it is a thiol ligand coordinated on the surface of the component (B1) and has a polymer structure containing at least one repeating unit selected from ethylene oxide and propylene oxide.

[0053] Such a thiol ligand includes, for example, a compound represented by the following formula (B2ex).

[0054] [ka] (R 1is 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 0 to 100. 2 is a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain a divalent heteroatom, and m is 0 to 100, provided that n+m>0. X is an ether, ester, or amide, and p is 0 to 1. The units represented by m and the units represented by n may be arranged randomly or in blocks.

[0055] Specific examples of the compound represented by the above formula (B2ex) include the following compounds.

[0056] [ka]

[0057] The polymer structure of such a thiol ligand is not particularly limited as long as it contains at least one repeating unit selected from ethylene oxide and propylene oxide, and examples thereof include a homopolymer consisting of (ethylene oxide) units, a homopolymer consisting of (propylene oxide) units, a random copolymer consisting of (ethylene oxide) units and (propylene oxide) units, and a block copolymer consisting of (ethylene oxide) units and (propylene oxide) units.

[0058] The thiol ligand of the component (B2) can be synthesized, for example, by the method described in JP-A-2020-523434. For other matters regarding the thiol ligand of the component (B2), refer to JP-A-2020-523434 as necessary.

[0059] The thiol ligand (B2) used in the present invention is preferably contained in an amount of 5 to 45 parts by mass, more preferably 10 to 40 parts by mass, and even more preferably 15 to 35 parts by mass, per 100 parts by mass of the quantum dot component (B1). When the amount of thiol ligand added is within the above range, it has good compatibility with the acrylic resin (A) having a (meth)acryloyl group in the side chain, making it possible to suppress the generation of aggregates and form patterns with high sensitivity and good shape.

[0060] [(C) Oxime-based photoradical generators] The oxime-based photoradical generator used in the present invention is not particularly limited as long as it is an oxime compound that can improve sensitivity during lithography.

[0061] Examples of the oxime compound include N-benzoyloxy-1-(4-phenylsulfanylphenyl)butan-1-one-2-imine, N-benzoyloxy-1-(4-phenylsulfanylphenyl)octan-1-one-2-imine, N-benzoyloxy-1-(4-phenylsulfanylphenyl)-3-cyclopentylpropan-1-one-2-imine, N-acetoxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethan-1-imine, N-acetoxy-1-[9- Examples of suitable compounds include ethyl-6-{2-methyl-4-(3,3-dimethyl-2,4-dioxacyclopentanylmethyloxy)benzoyl}-9H-carbazol-3-yl]ethan-1-imine, N-acetoxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-3-cyclopentylpropan-1-imine, and N-benzoyloxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-3-cyclopentylpropan-1-one-2-imine. Commercially available products such as Irgacure OXE01 and OXE02 (manufactured by BASF) and Adeka Arcles NCI-930 and NCI-730 (manufactured by ADEKA Corporation) may also be used.

[0062] The content of the oxime-based photoradical generator (C) used in the present invention is preferably 0.1 to 1.5 mass %, more preferably 0.2 to 1.3 mass %, of the nonvolatile components of the photosensitive resin composition. If the content of the oxime-based photoradical generator is within the above range, fine patterns can be formed while maintaining good light-emitting properties.

[0063] [(D) Surfactant] The surfactant (D) used in the present invention is not particularly limited as long as it can improve the coatability, but silicone surfactants are preferred.

[0064] Examples of silicone surfactants include surfactants having a siloxane bond in the molecule, such as Toray Silicone DC3PA, SH7PA, DC11PA, SH21PA, SH28PA, SH29PA, SH30PA, and SH8400 (trade names: manufactured by Dow Corning Toray Co., Ltd.), KP321, KP322, KP323, KP324, KP326, KP340, and KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), and TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF4446, TSF4452, and TSF4460 (manufactured by Momentive Performance Materials Japan, LLC).

[0065] The content of the surfactant (D) used in the present invention is preferably 0.001 to 0.7% by mass, more preferably 0.005 to 0.5% by mass, of the non-volatile components of the photosensitive resin composition. If the surfactant content is within the above range, a film with high flatness can be formed.

[0066] [(E) Solvent] The solvent (E) used in the present invention is not particularly limited as long as it can dissolve and disperse the above-mentioned components (A) to (D) and, if included, other various additives.

[0067] The (E) solvent is preferably an organic solvent, for example, 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; and 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 alone or in combination of two or more.

[0068] As the (E) solvent, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, cyclopentanone, and mixed solvents thereof are preferred, because they have excellent dispersibility of the (B1) quantum dots coordinated with the (B2) thiol ligand and excellent solubility of the (A) acrylic resin having a (meth)acryloyl group in the side chain.

[0069] From the viewpoint of compatibility and viscosity of the photosensitive resin composition, the content of the component (E) is preferably 25 to 85 mass %, more preferably 35 to 75 mass %, based on the total amount of the photosensitive resin composition.

[0070] [Other additives] The photosensitive resin composition of the present invention may contain other additives in addition to the above-mentioned components, such as a photopolymerizable compound such as a polyfunctional (meth)acrylate, for the purpose of increasing the crosslinking density and forming a pattern with a good shape after development.

[0071] [Silane coupling agents] The photosensitive resin composition of the present invention is preferably, but not limited to, free of a silane coupling agent. Without the addition of a silane coupling agent, the viscosity of the photosensitive resin composition increases over time, further reducing the risk of deterioration in storage stability. The cause of the increase in viscosity over time is not fully understood, but it is thought to be due to crosslinking of hydroxyl groups in the side chains of the acrylic resin.

[0072] [Photosensitive resin film] The photosensitive resin film of the present invention is a dried product of the above-mentioned photosensitive resin composition.

[0073] [Pattern Forming Method Using Photosensitive Resin Composition] The pattern forming method using the photosensitive resin composition of the present invention is (i) applying the 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) A step of developing the exposed photosensitive resin film with a developer to dissolve and remove the unexposed areas to form a pattern. Includes:

[0074] It is also preferable not to perform post-baking after the step (ii).

[0075] Step (i) is a step of applying the photosensitive resin composition to a substrate to form a photosensitive resin film on the substrate. The photosensitive resin film is a dried version of the photosensitive resin composition. Examples of the substrate include silicon wafers, glass wafers, quartz wafers, plastic circuit boards, and ceramic circuit boards.

[0076] The coating method may be a known method, such as dipping, spin coating, roll coating, etc. The amount of coating can be appropriately selected depending on the purpose, but it is preferable to coat so that the thickness of the resulting photosensitive resin film (dried product of the photosensitive resin composition) is preferably 0.1 to 50 μm, more preferably 1 to 30 μm.

[0077] Here, in order to efficiently carry out the photocuring reaction, the solvent and the like may be evaporated in advance by preheating (prebaking) as necessary. Prebaking can be carried out, for example, at 60 to 120°C for about 1 minute to 1 hour.

[0078] Next, in step (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, more preferably with light having a wavelength of 190 to 500 nm. Examples of light having such wavelengths include light of various wavelengths generated by a radiation generator, such as ultraviolet light such as g-line, h-line, and i-line, and far ultraviolet light (248 nm, 193 nm). Of these, light having a wavelength of 248 to 436 nm is particularly preferred. The exposure dose is 10 to 10,000 mJ / cm. 2 is preferred.

[0079] The exposure may be performed through a photomask. The photomask may be, for example, a photomask having a desired pattern cut out therein. The material of the photomask is not particularly limited, but is preferably one that blocks light of the wavelengths described above. For example, a photomask having a chromium light-shielding film is preferably used, but is not limited thereto.

[0080] Next, in step (iii), after exposure, the film is developed with a developer to form a pattern. Preferred examples of the developer include organic solvents such as alcohols such as IPA, ketones such as cyclohexanone, and glycols such as propylene glycol monomethyl ether. Examples of development methods include conventional methods, such as a dip method in which a patterned substrate is immersed in a developer, a paddle method in which the developer is dispensed with a paddle, and a spray method in which the developer is applied with a spray. By developing in this manner, the unexposed areas are dissolved and removed, forming a pattern. Thereafter, washing, rinsing, drying, etc. are performed as necessary to obtain a cured film having the desired pattern.

[0081] [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 formed on the support film.

[0082] The photosensitive dry film (support film and photosensitive resin film) is solid, and the photosensitive resin film does not contain a solvent, so there is no risk of bubbles due to volatilization remaining inside the photosensitive resin film or between the photosensitive resin film and the uneven substrate. The thickness of the photosensitive resin film is not particularly limited, but is preferably 1 to 100 μm, more preferably 3 to 50 μm.

[0083] Furthermore, at high temperatures, the viscosity and fluidity of the photosensitive resin film are closely related, and the photosensitive resin film can exhibit appropriate fluidity within an appropriate viscosity range, allowing it to penetrate deep into narrow gaps and strengthen adhesion to the substrate by softening the resin. Therefore, from the viewpoint of the fluidity of the photosensitive resin film, the viscosity of the photosensitive resin film at high temperatures is preferably 10 to 5,000 Pa·s, and more preferably 30 to 2,000 Pa·s, at 80°C. In the present invention, the viscosity is measured using a rotational viscometer.

[0084] When the photosensitive dry film of the present invention is adhered to a substrate having an uneven surface, the photosensitive resin film conforms to the uneven surface to achieve high flatness. In particular, the photosensitive resin composition of the present invention has softening properties, which allows for even higher flatness. Furthermore, when the photosensitive resin film is adhered to the substrate in a vacuum environment, the occurrence of gaps can be more effectively prevented.

[0085] The photosensitive dry film of the present invention can be produced by applying the photosensitive resin composition to a support film and drying it to form a photosensitive resin film. A film coater typically used for producing adhesive products can be used as the photosensitive dry film production equipment. Examples of the film coater include a comma coater, a comma reverse coater, a multicoater, a die coater, a lip coater, a lip reverse coater, a direct gravure coater, an offset gravure coater, a three-roll bottom reverse coater, and a four-roll bottom reverse coater.

[0086] A photosensitive dry film can be produced by applying the photosensitive resin composition to a predetermined thickness onto a support film as it is unwound from the unwinding shaft of the film coater and passed through the coater head of the film coater. The film is then passed through a hot air circulating oven at a predetermined temperature and time, and dried on the support film to form a photosensitive resin film. If necessary, the photosensitive dry film can be passed through a laminating roll at a predetermined pressure together with a protective film unwound from another unwinding shaft of the film coater to bond the photosensitive resin film on the support film to the protective film. The photosensitive dry film with a protective film can then be produced by winding the film 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.

[0087] 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 consisting of multiple laminated films. Examples of materials for the film include synthetic resin films such as polyethylene, polypropylene, polycarbonate, and polyethylene terephthalate. Among these, polyethylene terephthalate is preferred, as it has moderate flexibility, mechanical strength, and heat resistance. These films may also be subjected to various treatments such as corona treatment or release agent coating. Commercially available products are available, such as Cerapeel WZ (RX) and Cerapeel BX8 (R) (manufactured by Toray Advanced Film Co., Ltd.), E7302 and E7304 (manufactured by Toyobo Co., Ltd.), Purex G31 and Purex G71T1 (manufactured by Teijin DuPont Films Co., Ltd.), PET38x1-A3, PET38x1-V8, and PET38x1-X08 (manufactured by Nippa Corporation).

[0088] The protective film may 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 for these, and examples of polyethylene terephthalate include those already exemplified, and examples of polyethylene include GF-8 (manufactured by Tamapoly Corporation) and PE Film 0 Type (manufactured by Nippa Corporation).

[0089] The thickness of each of the support film and the protective film is preferably 10 to 100 μm, more preferably 25 to 50 μm, from the viewpoints of stability in the production of the photosensitive dry film and prevention of curling around the core.

[0090] [Pattern formation method using photosensitive dry film] The pattern forming method using the photosensitive dry film of the present invention comprises the steps of: (i') a step of attaching the photosensitive resin film of the photosensitive dry film onto a substrate to form the photosensitive resin film on the substrate; (ii') exposing the photosensitive resin film to light; and (iii') A step of developing the exposed photosensitive resin film with a developer to dissolve and remove the unexposed areas to form a pattern. Includes:

[0091] It is also preferable not to perform post-baking after the step (ii').

[0092] First, in step (i'), a photosensitive resin film is attached to a substrate using a photosensitive dry film, thereby forming a photosensitive resin film on the substrate. That is, the photosensitive resin film of the photosensitive dry film is attached to the substrate, thereby forming a photosensitive resin film on the substrate. Furthermore, if the photosensitive dry film has a protective film, the protective film is peeled off from the photosensitive dry film, and then the photosensitive resin film of the photosensitive dry film is attached to the substrate. The attachment can be performed, for example, using a film attachment device.

[0093] The film laminating device is preferably a vacuum laminator. For example, the protective film of the photosensitive dry film is peeled off, and the exposed photosensitive resin film is adhered to the substrate on a table at a predetermined temperature using a laminating roll at a predetermined pressure in a vacuum chamber at 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.

[0094] In order 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 carried out as necessary. Pre-baking can be carried out, for example, at 60 to 120°C for about 1 minute to 1 hour.

[0095] As in the case of the pattern formation method using the photosensitive resin composition, the photosensitive resin film attached to the substrate can be patterned by undergoing the steps of (ii') exposing the photosensitive resin film to light and (iii') developing the exposed photosensitive resin film with a developer to dissolve and remove the unexposed areas to form a pattern. Note that the support film of the photosensitive dry film is peeled off before the development step depending on the process.

[0096] The pattern formation method using the photosensitive resin composition and dry film of the present invention allows for easy formation of fine patterns. For example, the photosensitive resin composition of the present invention can be deposited to cover numerous blue micro LEDs arranged on a substrate, followed by fine pattern formation to form a cured film containing red and green quantum dots on each portion of the blue micro LED. This allows for red and green light emission, making it possible to fabricate a full-color display device. This method can also be applied to mini LEDs.

[0097] [Display device] The present invention also provides a display device having a pattern formed from a cured film of the photosensitive resin composition of the present invention. The pattern formed from the cured film of the photosensitive resin composition of the present invention can be obtained by the above-described pattern forming method.

[0098] Furthermore, the display device of the present invention can be a display device that has a pattern made of a cured film of the photosensitive resin composition of the present invention above a blue LED, and extracts light color-converted by quantum dots from each subpixel.

[0099] [Micro LED display] In the present invention, a pattern made of a cured film of the photosensitive resin composition of the present invention is provided above a blue LED, and the size of the pattern made of the cured film is 0.01 mm. 2 The present invention provides a micro LED display that extracts light color-converted by quantum dots from each sub-pixel. [Example]

[0100] EXAMPLES The present invention will be specifically explained below using examples and comparative examples, but the present invention is not limited to these.

[0101] [1] Preparation of photosensitive resin composition and its evaluation [Examples R1 to 7, G1 to 7 and Comparative Examples R1 to 14, G1 to 14] The components were blended according to the blending amounts shown in Tables 1 to 6, then stirred and mixed at room temperature, and microfiltered through a 1.0 μm glass filter to obtain photosensitive resin compositions (PGMEA solutions) of Examples R1 to 7 and G1 to 7 and Comparative Examples R1 to 14 and G1 to 14. In the tables, the total solid content (components other than (E) solvent) is shown to be 100.

[0102] [Table 1]

[0103] [Table 2]

[0104] [Table 3]

[0105] [Table 4]

[0106] [Table 5]

[0107] [Table 6]

[0108] In Tables 1 to 6, A-1 is a product manufactured by Negami Chemical Industries Co., Ltd. under the trade name "RA-3631P" (an acrylic resin with a molecular weight of 18,000, an acid value of 5 mg KOH / g, and a double bond equivalent of 250 g / mol), A-2 is a product manufactured by Taisei Fine Chemical Co., Ltd. under the trade name "8KQ-7060" (an acrylic resin with a molecular weight of 33,000, an acid value of 10 mg KOH / g, and a double bond equivalent of 260 g / mol), and A'-1 is a product manufactured by Taisei Fine Chemical Co., Ltd. under the trade name "PH-9001" (a urethane resin with a molecular weight of 20,000, an acid value of 41 mg KOH / g, and a double bond equivalent of 890 g / mol). Mw is data measured by GPC.

[0109] In Tables 1 to 6, B1R-1 is a core-shell quantum dot (red emission) with a core / shell = InP / ZnSe and a maximum fluorescence wavelength of 629 nm, B1G-1 is a core-shell quantum dot (green emission) with a core / shell = InP / ZnSe and a maximum fluorescence wavelength of 521 nm, B1R-2 is a core-shell quantum dot (red emission) with a core / shell = AgGaSe / ZnS and a maximum fluorescence wavelength of 631 nm, and B1G-2 is a core-shell quantum dot (green emission) with a core / shell = AgGaSe / ZnS and a maximum fluorescence wavelength of 530 nm. The particle diameters of the above quantum dots are 5 to 10 nm for red and 3 to 5 nm for green.

[0110] In Tables 1 to 6, B2-1 and B2-2 are as follows, and were synthesized by the method described in JP-A-2020-523434. B2'-1 is oleic acid, and B2'-2 is dodecanethiol.

[0111] [ka]

[0112] In Tables 1 to 6, C-1 is the product manufactured by BASF under the trade name "Irgacure OXE01" (oxime ester type), C-2 is the product manufactured by ADEKA Corporation under the trade name "ADEKA ARCLES NCI-730" (oxime ester type), C'-1 is the product manufactured by BASF under the trade name "Irgacure 184" (hydroxyalkylphenone type), C'-2 is the product manufactured by BASF under the trade name "Irgacure 819" (acylphosphine oxide type), and C'-3 is the product manufactured by BASF under the trade name "Irgacure 369" (aminoalkylphenone type).

[0113] [ka]

[0114] In Tables 1 to 6, D-1 is the product name "KP341" (polyether type silicone surfactant) manufactured by Shin-Etsu Chemical Co., Ltd.

[0115] In Tables 1 to 6, A'-2 was synthesized as follows. 265.0 g (1.00 mol) of the following compound (S-5) was added to a 3 L flask equipped with a stirrer, thermometer, nitrogen purge device, and reflux condenser, followed by the addition of 2,000 g of toluene and heating to 70°C. 1.0 g of a toluene solution of chloroplatinic acid (platinum concentration 0.5% by mass) was then added, followed by the addition of 164.9 g (0.85 mol) of the following compound (S-1) and the following compound (S-2) (y 1 To the reaction mixture, 453.0 g (0.15 mol) of hydroxypropyl methylcellulose (HMP-40, manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise over 1 hour (total hydrosilyl groups / total alkenyl groups = 1 / 1 (molar ratio)). After the addition was completed, the mixture was heated to 100°C and aged for 6 hours. Toluene was then removed from the reaction mixture by distillation under reduced pressure to obtain Resin A'-2 with a Mw of 65,000.

[0116] [ka]

[0117] In Tables 1 to 6, the photoacid generator F-1 used was "CPI-210S" manufactured by San-Apro Co., Ltd.

[0118] [ka]

[0119] In Tables 1 to 6, the epoxy crosslinking agent G-1 is as follows:

[0120] [ka]

[0121] [2] Preparation of photosensitive dry film Using a die coater as the film coater and a polyethylene terephthalate film (38 μm thick) as the support film, each of the photosensitive resin compositions listed in Tables 1 to 6 was applied onto the support film. The film was then dried by passing it through a hot air circulating oven (4 m long) set at 80°C for 5 minutes, forming a photosensitive resin film on the support film to a thickness of 5 μm, thereby obtaining a photosensitive dry film. A polyethylene film (50 μm thick) was laminated onto the photosensitive resin film as a protective film at a pressure of 1 MPa using a laminating roll, producing a photosensitive dry film with a protective film. When peeling off the protective film from the produced dry film, if the photosensitive resin film was found to have adhered to the protective film and peeled off from the base film in even one place, it was marked with an "X", and if there was no problem, it was marked with an "O". The results are shown in Tables 7 to 12.

[0122] [3] Pattern formation and its evaluation The protective film was peeled off from the photosensitive dry film with the protective film attached, and the photosensitive resin film on the support film was adhered to a silicon wafer using a vacuum laminator TEAM-100RF (manufactured by Takatori Corporation) with the vacuum level set to 80 Pa in the vacuum chamber. The temperature condition was 100°C. After returning to normal pressure, the substrate was removed from the vacuum laminator and the support film was peeled off. Next, to improve adhesion to the substrate, the substrate was pre-baked on a hot plate at 100°C for 2 minutes. The obtained photosensitive resin film was exposed to light using an i-line stepper NSR-2205i11D (manufactured by Nikon Corporation) through a mask to form a square island pattern with a 1:1 pitch between adjacent patterns. After irradiation, spray development was performed with PGMEA for 20 seconds to form a pattern. The formed island patterns, each measuring 50 μm, 20 μm, 10 μm, 5 μm, and 3 μm on a side, were then observed using a scanning electron microscope (SEM). The smallest pattern size that was not connected to adjacent island patterns (with a 1:1 pitch) was taken as the limiting resolution. The perpendicularity of the patterns was also evaluated, with perpendicular patterns being rated as "Good" and patterns with tapered shapes or poor openings being rated as "Poor." The results are shown in Tables 7 to 12. Patterns in which aggregates of 0.5 μm or larger were observed were rated as "Poor," and patterns in which no aggregates were observed were rated as "Good." The results are shown in Tables 7 to 12.

[0123] [4] Remaining rate of quantum dots in the pattern after development and solvent resistance test A 4 cm-side island pattern was formed on a glass wafer using the same method as described above. The absorbance of light at a wavelength of 460 nm was measured for both the exposed and developed films using a spectrophotometer U-3900H (Hitachi High-Tech Science Corporation). Because absorbance is proportional to the amount of remaining quantum dots, the percentage of quantum dots remaining after development can be calculated by dividing the absorbance after development by the ratio of the absorbance after exposure. The patterned sample was then immersed in PGMEA for one hour, after which the absorbance was measured again. The percentage of remaining quantum dots was calculated by dividing the absorbance after the solvent resistance test by the absorbance after exposure. The results are shown in Tables 7 to 12.

[0124] [5] Luminescence properties and light resistance test of cured film A photosensitive dry film with a protective film was prepared in the same manner as above, with a photosensitive resin film thickness of 30 μm. After peeling off the protective film, the film was irradiated with light from a high-pressure mercury lamp (wavelength 360 nm) using a SUSS MicroTec mask aligner MA8 without a mask, and the substrate film was then peeled off to produce a cured film. Then, using a quantum efficiency measurement system (QE-2100 manufactured by Otsuka Electronics) and an excitation wavelength of 460 nm, emission characteristics such as quantum yield, maximum fluorescence wavelength, and half-width were measured. Furthermore, the film was then measured using an Atlas Suntest XLS+ manufactured by Toyo Seiki Seisakusho Co., Ltd. at an illuminance of 65 W / m. 2 A sunlight light resistance test was then conducted for 500 hours at an environmental temperature of 100° C., and the quantum yield was measured again to determine the rate of change before and after the light resistance test. The results are shown in Tables 7 to 12.

[0125] [Table 7]

[0126] [Table 8]

[0127] [Table 9]

[0128] [Table 10]

[0129] [Table 11]

[0130] [Table 12]

[0131] As shown in Tables 7 to 12, Examples R1 to R7 and G1 to G7, which are photosensitive resin compositions of the present invention, were successfully peeled from the protective film, capable of forming vertical patterns with high resolution, free of aggregates, with little loss of quantum dots after development and solvent resistance tests, and exhibiting good and sustained luminescence properties. On the other hand, Comparative Examples R1 to 14 and G1 to G14, which are photosensitive resin compositions lacking one or more of (A) an acrylic resin having a (meth)acryloyl group in its side chain, (B2) a thiol ligand, and (C) an oxime-based photoradical generator, were poor in pattern formation, quantum dot residual rate, and luminescence properties. Comparative Examples R1 to R8 and G1 to G8 also exhibited poor peeling from the protective film.

[0132] The above results demonstrate that the photosensitive resin composition of the present invention can form good photosensitive coatings and photosensitive dry films, has lithography performance with high rectangularity and resolution, has no aggregates in the formed patterns (or if any, they are extremely small), has a high rate of quantum dot retention in the patterns after development and solvent resistance tests, and has cured films with high luminescence properties and good reliability (low rate of change in luminescence intensity in sunlight resistance tests), making it possible to provide materials suitable for display devices (particularly micro LED displays).

[0133] This specification includes the following inventions.

[0134] [1]: A photosensitive resin composition comprising: (A) an acrylic resin having a (meth)acryloyl group in a side chain; (B1) quantum dots; (B2) a thiol ligand coordinated to the surface of the component (B1), the thiol ligand having a polymer structure containing at least one repeating unit selected from ethylene oxide and propylene oxide; (C) an oxime-based photoradical generator; (D) a surfactant; and (E) a solvent.

[0135] [2]: The photosensitive resin composition according to [1] above, wherein the component (A) is an alkali-insoluble resin having a weight-average molecular weight Mw of 10,000 to 50,000, a double bond equivalent of ≦300 g / mol, and an acid value of ≦10 mg KOH / g.

[0136] [3]: The photosensitive resin composition according to [1] or [2] above, wherein the component (B1) has a core-shell structure including a core and a shell covering the core, the core including one or more compounds formed by 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 including one or more compounds formed by a combination of two or more of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Hg, N, As, O, Mn, and Sr.

[0137] [4]: The photosensitive resin composition according to any one of [1] to [3] above, wherein the component (B1) is contained in an amount of 10 to 50 mass % in the non-volatile components of the photosensitive resin composition.

[0138] [5]: The photosensitive resin composition according to any one of the above [1] to [4], wherein the component (B2) is contained in an amount of 5 to 45 parts by mass per 100 parts by mass of the component (B1).

[0139] [6]: The photosensitive resin composition according to any one of [1] to [5] above, wherein the component (C) is contained in an amount of 0.1 to 1.5 mass % in the non-volatile components of the photosensitive resin composition.

[0140] [7]: A photosensitive resin film, which is a dried product of the photosensitive resin composition according to any one of [1] to [6] above.

[0141] [8]: A photosensitive dry film comprising a support film and the photosensitive resin film according to [7] above formed on the support film.

[0142] [9]: A pattern formation method, comprising: (i) a step of applying the photosensitive resin composition according to any one of the above [1] to [6] 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 to dissolve and remove unexposed areas to form a pattern.

[0143]

[10] : The pattern forming method according to the above [9], wherein post-baking is not performed after the step (ii).

[0144]

[11] : A pattern formation method comprising the steps of: (i') attaching the photosensitive resin film of the photosensitive dry film described in [8] above onto a substrate to form the 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 to dissolve and remove unexposed areas to form a pattern.

[0145]

[12] : The pattern forming method according to the above

[11] , wherein post-baking is not performed after the step (ii').

[0146]

[13] : A display device characterized by comprising a pattern made of a cured film of the photosensitive resin composition according to any one of [1] to [6] above.

[0147]

[14] : A display device characterized in that a pattern made of a cured film of the photosensitive resin composition according to any one of [1] to [6] above is provided above a blue LED, and light color-converted by quantum dots is extracted from each subpixel.

[0148]

[15] : A pattern made of a cured film of the photosensitive resin composition according to any one of [1] to [6] above a blue LED is provided, and the size of the pattern made of the cured film is 0.01 mm 2A micro LED display characterized by extracting light color-converted by quantum dots from each subpixel.

[0149] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. (A) an acrylic resin having a (meth)acryloyl group in a side chain; (B1) quantum dots, (B2) a thiol ligand coordinated to the surface of the component (B1), the thiol ligand having a polymer structure containing at least one repeating unit selected from ethylene oxide and propylene oxide; (C) an oxime-based photoradical generator, (D) a surfactant, and (E) Solvent A photosensitive resin composition comprising:

2. 2. The photosensitive resin composition according to claim 1, wherein the component (A) is an alkali-insoluble resin having a weight-average molecular weight Mw of 10,000 to 50,000, a double bond equivalent of ≦300 g / mol, and an acid value of ≦10 mg KOH / g.

3. 2. The photosensitive resin composition according to claim 1, wherein the component (B1) has a core-shell structure including a core and a shell covering the core, the core including at least one compound formed by 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 including at least one compound formed by a combination of two or more of In, P, Zn, Ga, Cd, Se, S, Te, Pb, Hg, N, As, O, Mn, and Sr.

4. 2. The photosensitive resin composition according to claim 1, wherein the component (B1) is contained in an amount of 10 to 50% by mass of the nonvolatile components of the photosensitive resin composition.

5. 2. The photosensitive resin composition according to claim 1, wherein the component (B2) is contained in an amount of 5 to 45 parts by mass per 100 parts by mass of the component (B1).

6. 2. The photosensitive resin composition according to claim 1, wherein the component (C) is contained in an amount of 0.1 to 1.5% by mass in the nonvolatile components of the photosensitive resin composition.

7. A photosensitive resin film, which is a dried product of the photosensitive resin composition according to any one of claims 1 to 6.

8. A photosensitive dry film comprising a support film and the photosensitive resin film according to claim 7 formed on the support film.

9. A pattern formation method, comprising: (i) applying the photosensitive resin composition according to any one of claims 1 to 6 onto a substrate to form a photosensitive resin film on the substrate; (ii) exposing the photosensitive resin film to light; and (iii) A step of developing the exposed photosensitive resin film with a developer to dissolve and remove the unexposed areas to form a pattern. A pattern forming method comprising the steps of:

10. 10. The pattern formation method according to claim 9, wherein post-baking is not performed after the step (ii).

11. A pattern formation method, comprising: (i') a step of attaching the photosensitive resin film of the photosensitive dry film according to claim 8 onto a substrate to form the photosensitive resin film on the substrate; (ii') exposing the photosensitive resin film to light; and (iii') A step of developing the exposed photosensitive resin film with a developer to dissolve and remove the unexposed areas to form a pattern. A pattern forming method comprising the steps of:

12. 12. The pattern formation method according to claim 11, wherein post-baking is not performed after the step (ii').

13. A display device comprising a pattern formed from a cured film of the photosensitive resin composition according to any one of claims 1 to 6.

14. A display device comprising a pattern made of a cured film of the photosensitive resin composition according to any one of claims 1 to 6 above a blue LED, and wherein light color-converted by quantum dots is extracted from each subpixel.

15. A pattern made of a cured film of the photosensitive resin composition according to any one of claims 1 to 6 is provided above a blue LED, and the size of the pattern made of the cured film is 0.01 mm ２ A micro LED display characterized in that light color-converted by quantum dots is extracted from each subpixel.

Images