Negative-type radiation-sensitive resin composition, insulating film for organic EL element, method for forming the same, and organic EL device

Abstract

To provide a negative type radiation-sensitive resin composition which enables production of a cured film that has sufficient lithography performance, and has sufficient chemical liquid resistance and oxygen ashing resistance even by heating at comparatively low temperature, an insulating film for an organic EL element and a method for forming the same, and an organic EL device.SOLUTION: A negative type radiation-sensitive resin composition contains (A) a polysiloxane having at least one thiol group, (B) a polyfunctional methacrylate and (C) a photopolymerization initiator, and has a viscosity measured using an E type viscometer under conditions of 25°C and 50 rpm of 0.5 mPa s or more and 20 mPa s or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a negative-type radiation-sensitive resin composition, an insulating film for an organic EL element, a method for forming the same, and an organic EL device.

Background Art

[0002] As one of the light-emitting elements that have been developed in recent years, an organic electroluminescence (EL) element having a laminated structure including an anode layer, an organic light-emitting layer, and a cathode layer is known. As a display device having an organic EL element, an organic EL device with a touch panel provided on the front surface of the device is known (see Patent Document 1).

[0003] An organic EL device with a touch panel is manufactured, for example, by bonding a touch panel to a substrate on which an organic EL element is formed via an adhesive layer. A touch panel is usually manufactured by providing touch panel members such as sensor electrodes on a support substrate for the touch panel.

[0004] On the other hand, Patent Document 2 discloses a curable resin composition containing a silsesquioxane having a thiol group and a compound having a plurality of allyl groups, and it is described that the composition can be used for forming a coating layer or an adhesive layer of a liquid crystal panel, an EL panel, etc. Further, Patent Document 3 discloses a photosensitive composition containing a polysiloxane having a thiol group and a polyfunctional acrylate compound, and it is described that the durability of a pattern film can be enhanced by forming a pattern film on a substrate using the composition.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, when a touch panel is bonded to a substrate on which an organic EL element is formed via an adhesive layer, the thickness of the entire organic EL device with a touch panel increases. In the case of a device with a large thickness, breakage or functional degradation is likely to occur when it is bent. Also, in various display devices, thinning itself is desired. Therefore, it is considered that by directly providing a touch panel on a substrate on which an organic EL element is formed by means such as lithography and etching, the thickness of the entire display device such as an organic EL device with a touch panel can be reduced.

[0007] However, in a conventional method using a material containing a polyfunctional (meth)acrylate or the like as a curable component, heating at a temperature exceeding 100°C, preferably exceeding 120°C, is required for curing the insulating film for forming the touch panel. When forming an insulating film on a substrate on which an organic EL element is formed, there is a disadvantage that the organic light-emitting layer deteriorates due to heating at a temperature exceeding 100°C, particularly exceeding 120°C.

[0008] On the other hand, when the insulating film is formed by heating at 120°C or lower, particularly 100°C or lower, using a conventional material, the obtained insulating film cannot withstand an etching chemical solution or oxygen ashing for wiring formation, and it tends to be difficult to fabricate a touch panel structure. Not limited to the insulating film for an organic EL device with a touch panel, in various applications such as insulating films for other display devices, the development of a radiation-sensitive resin composition capable of obtaining an insulating film having sufficient etching chemical solution resistance and oxygen ashing resistance even by relatively low-temperature heating is desired.

[0009] The present invention has been made based on the above circumstances, and aims to provide a negative-type radiation-sensitive resin composition capable of obtaining a cured film having sufficient lithography performance and sufficient chemical resistance and oxygen ashing resistance even by heating at a relatively low temperature (for example, 120 ° C or lower), an insulating film for an organic EL element obtained by using the above negative-type radiation-sensitive resin composition, an organic EL device, and a method for forming an insulating film for an organic EL element using the above negative-type radiation-sensitive resin composition.

Means for Solving the Problems

[0010] The invention made to solve the above problems is a negative-type radiation-sensitive resin composition described in the following [1] or [2]. 〔1〕A negative-type radiation-sensitive resin composition containing (A) a polysiloxane having at least one thiol group, (B) a polyfunctional methacrylate, and (C) a photopolymerization initiator. 〔2〕A negative-type radiation-sensitive resin composition containing (A) a polysiloxane having at least one thiol group, (B) a polyfunctional methacrylate, and (C) a photopolymerization initiator, and having a viscosity measured at 25 ° C and 50 rpm using an E-type viscometer of 0.5 mPa·s or more and 20 mPa·s or less.

[0011] Another invention made to solve the above problems is an insulating film for an organic EL element formed by the above negative-type radiation-sensitive resin composition described in [1] or [2].

[0012] Another invention made to solve the above problems is a method for forming an insulating film for an organic EL element, comprising a step of forming a coating film by applying the above negative-type radiation-sensitive resin composition described in [1] or [2] directly or indirectly on a substrate, a step of irradiating at least a part of the coating film with radiation after the step of forming the coating film, a step of developing the coating film after the step of irradiating the radiation, and a step of heating the coating film at a temperature of 60 ° C or higher and 120 ° C or lower after the step of developing the coating film.

[0013] Yet another invention made to solve the above problems is an organic EL device including the above-described insulating film for an organic EL element.

Advantages of the Invention

[0014] According to the present invention, there are provided a negative-type radiation-sensitive resin composition capable of obtaining a cured film having sufficient lithography performance and sufficient chemical resistance and oxygen ashing resistance even by heating at a relatively low temperature, an insulating film for an organic EL element obtained by using the negative-type radiation-sensitive resin composition, an organic EL device, and a method for forming an insulating film for an organic EL element using the negative-type radiation-sensitive resin composition. Note that the curable resin composition described in Patent Document 2 contains a compound having a plurality of allyl groups. Since the allyl group has low reactivity, only the ene-thiol reaction proceeds. On the other hand, since the negative-type radiation-sensitive resin composition of the present invention contains a polyfunctional methacrylate, the ene-thiol reaction with the methacrylate group and a normal radical polymerization reaction proceed simultaneously. Therefore, according to the present invention, a cured film having excellent low-temperature curability and excellent solvent resistance can be obtained. In addition, the photosensitive composition described in Patent Document 3 contains a polyfunctional acrylate. Although the acrylate group has excellent reactivity, the ene-thiol reaction proceeds during storage of the composition, so the viscosity of the composition increases and the storage stability is poor. On the other hand, since the negative-type radiation-sensitive resin composition of the present invention contains a polyfunctional methacrylate, a composition having excellent storage stability can be provided.

Brief Description of the Drawings

[0015]

Figure 1

Embodiments for Carrying Out the Invention

[0016] <Negative-Type Radiation-Sensitive Resin Composition> A negative-type radiation-sensitive resin composition according to an embodiment of the present invention contains (A) a polysiloxane having at least one thiol group (hereinafter also referred to as “component (A)”), (B) a polyfunctional methacrylate (hereinafter also referred to as “component (B)”), and (C) a photopolymerization initiator (hereinafter also referred to as “component (C)”), and is preferably a negative-type radiation-sensitive resin composition having a viscosity of 0.5 mPa·s or more and 20 mPa·s or less as measured using an E-type viscometer under the conditions of 25° C. and 50 rpm.

[0017] According to the negative-type radiation-sensitive resin composition, by containing component (A), component (B), and component (C), and preferably having the viscosity within the above range, it has sufficient lithography performance, and a cured film having sufficient chemical resistance and oxygen ashing resistance can be obtained even by heating at a relatively low temperature. The reason for this is not clear, but it is presumed as follows. That is, in the negative-type radiation-sensitive resin composition, the thiol group of the polysiloxane functions as an alkali-soluble group and a crosslinking group, so it is presumed that the dissolution contrast of the obtained cured film becomes high, and thereby excellent lithography performance is exhibited. In addition, a cured film having a structure in which a siloxane structure and a methacryl structure coexist is obtained by forming a crosslinked structure between the polysiloxane having a siloxane structure and the polyfunctional methacrylate having a methacryl structure through an ene-thiol reaction. Therefore, it is presumed that the obtained cured film is excellent in stress relaxation, and thereby chemical resistance and oxygen ashing resistance are exhibited. Hereinafter, each component of the negative-type radiation-sensitive resin composition will be described.

[0018] (A) A polysiloxane having at least one thiol group The negative-type radiation-sensitive resin composition contains (A) a polysiloxane having at least one thiol group. In addition to component (A), the negative-type radiation-sensitive resin composition contains a compound ((B) polyfunctional methacrylate) having two or more functional groups capable of reacting with a thiol group in one molecule, and by reacting component (A) and component (B) with each other, an insulating film excellent in curability is formed. Further, component (A) is a polysiloxane having a siloxane bond.

[0019] When the negative-type radiation-sensitive resin composition contains a polysiloxane having a siloxane bond, generation of outgas during production of an insulating film can be suppressed, and an insulating film for an organic EL element excellent in coatability and transparency of the insulating film can be obtained.

[0020] In addition, a compound having a thiol group can be photocured by an ene-thiol reaction with a compound having a carbon-carbon double bond. The ene-thiol reaction has advantages such as proceeding by ultraviolet irradiation regardless of the presence or absence of a polymerization initiator, not being inhibited by oxygen, and having a small curing shrinkage as compared with a radical polymerization system generally used in a photocuring system.

[0021] The component (A) is a compound obtained by hydrolyzing and condensing thiol group-containing alkoxysilanes (a1) represented by the following formula (2) (hereinafter also referred to as "component (a1)").

[0022] R 1 Si(OR 2 )3(2)

[0023] In the above formula (2), R 1 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms and at least one thiol group, or an aromatic hydrocarbon group having 6 to 8 carbon atoms and at least one thiol group, and R 2 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 8 carbon atoms.

[0024] The aliphatic hydrocarbon group having 1 to 8 carbon atoms may be linear or branched. For example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a hexyl group, a heptyl group, and an octyl group can be mentioned. In the case of the aromatic hydrocarbon group having 6 to 8 carbon atoms, the "aromatic hydrocarbon group" is a concept that includes not only a group consisting only of a ring structure but also a group in which a divalent aliphatic hydrocarbon group is further substituted on the ring structure, and it suffices that at least an alicyclic hydrocarbon or an aromatic hydrocarbon is included in its structure. For example, a phenyl group, a benzyl group, a phenethyl group, a tolyl group, and a xylyl group can be mentioned. Among them, R 1 is preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms and having at least one thiol group from the viewpoint of low-temperature curability, and R 2 is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms from the viewpoint of hydrolyzability.

[0025] Specific examples of the component (a1) represented by the above formula (2) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropyltributoxysilane, 1,4-dimercapto-2-(trimethoxysilyl)butane, 1,4-dimercapto-2-(triethoxysilyl)butane, 1,4-dimercapto-2-(tripropoxysilyl)butane, 1,4-dimercapto-2-(tributoxysilyl)butane, 2-mercaptomethyl-3-mercaptopropyltrimethoxysilane, 2-mercaptomethyl-3-mercaptopropyltriethoxysilane, 2-mercaptomethyl-3-mercaptopropyltripropoxysilane, 2-mercaptomethyl-3-mercaptopropyltributoxysilane, 1,2-dimercaptoethyltrimethoxysilane, 1,2-dimercaptoethyltriethoxysilane, 1,2-dimercaptoethyltripropoxysilane, 1,2-dimercaptoethyltributoxysilane, etc. Any of the above-exemplified compounds can be used alone or in an appropriate combination. Among the above-exemplified compounds, 3-mercaptopropyltrimethoxysilane is particularly preferable because of its high reactivity in the hydrolysis reaction and easy availability.

[0026] In addition to component (a1), alkyltrialkoxysilanes (a2) such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane (hereinafter also referred to as "component (a2)") can be used. Component (a2) can be used either alone or in combination of two or more. By using these, the content of the thiol group can be adjusted, so that the refractive index of the finally obtained insulating film can be adjusted.

[0027] When component (a1) and component (a2) are used in combination, it is preferable that [the number of moles of component (a2)] / [the total number of moles of component (a1) and component (a2)] (molar ratio) is 0.7 or less, and more preferably 0.5 or less. When the above molar ratio exceeds 0.7, the number of thiol groups contained in the obtained component (A) decreases, so that the curability of the insulating film decreases and the improvement effect on physical properties such as the hardness of the insulating film may also be insufficient. On the other hand, the above molar ratio may be 0, but it may also be set appropriately above 0.

[0028] (Component (A) can be obtained by hydrolyzing component (a1) alone or in combination with component (a2) and then condensing them. By the hydrolysis reaction, the alkoxy groups contained in component (a1) and component (a2) become silanol groups, and alcohol is by-produced. The amount of water required for the hydrolysis reaction may be such that, for example, [moles of water used in the hydrolysis reaction] / [total moles of each alkoxy group contained in component (a1) and component (a2)] (molar ratio) is 0.4 or more and 10 or less. When the molar ratio is 0.4 or more and less than 0.5, some alkoxy groups will remain in the obtained component (A), but the adhesion to the inorganic material will be improved. When the molar ratio is 0.5 or more and 10 or less, substantially no alkoxy groups remain in the obtained component (A), so a cured product of the thick film is easy to produce. On the other hand, when the molar ratio is less than 0.4, too many alkoxy groups that remain unhydrolyzed in component (A) will be generated, so a large amount of volatile components will be generated during curing, and it is difficult to produce a cured product of the thick film, which is not preferable. When the molar ratio exceeds 10, the amount of water to be removed during the subsequent condensation reaction (dehydration reaction) will increase, which is economically disadvantageous.)

[0029] As the catalyst used in the hydrolysis reaction, an acidic catalyst that can function as a conventionally known hydrolysis catalyst can be arbitrarily used. However, since it is necessary to substantially remove the acidic catalyst after the hydrolysis reaction, it is preferably one that is easy to remove. As such a substance, formic acid, which has high catalytic activity and a low boiling point and can be removed by reduced pressure, is preferred. As the above catalyst, it can be easily removed by methods such as filtration, and examples include solid acid catalysts that are insoluble in component (a1), component (a2), their hydrolysis products, the solvent used during hydrolysis, and water. Examples of solid acid catalysts include cation exchange resins, activated clay, carbon-based solid acids, etc. Among them, cation exchange resins are preferred because they have high catalytic activity and are easily available. As the cation exchange resin, a strong acid type cation exchange resin or a weak acid type cation exchange resin can be used. Examples of strong acid type ion exchange resins include Diaion SK series, UBK series, PK series, HPK25·PCP series (all are trade names of Mitsubishi Chemical Corporation), Amberlite IR120B, IR124, 200CT, 252, Amberjet 1020, 1024, 1060, 1220, Amberlyst 15DRY, 15JWET, 16WET, 31WET, 35WET (all are trade names of Organo Corporation), etc. Examples of weak acid type ion exchange resins include Diaion WK series, WK40 (all are trade names of Mitsubishi Chemical Corporation), Amberlite FPC3500, IRC76 (all are trade names of Organo Corporation), etc. The type of ion exchange resin to be used can be arbitrarily selected depending on the reaction rate and suppression of side reactions, etc., but strong acid type ion exchange resins are particularly preferred due to their reactivity.

[0030] The addition amount of the acidic catalyst is preferably 0.1 part by mass or more and 25 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, based on 100 parts by mass in total of component (a1) and component (a2). When the above addition amount exceeds 25 parts by mass, it tends to be difficult to remove in the subsequent process or become economically disadvantageous. On the other hand, when the above addition amount is less than 0.1 part by mass, the reaction does not substantially proceed or the reaction time tends to become long, etc.

[0031] The reaction temperature and reaction time can be arbitrarily set according to the reactivity of component (a1) and component (a2). The reaction temperature is usually about 0°C or higher and 100°C or lower, preferably about 20°C or higher and 60°C or lower. The reaction time is about 1 minute or longer and 2 hours or shorter. The above hydrolysis reaction can be carried out in the presence or absence of a solvent, but it is preferable not to use a solvent. When using a solvent, the type of solvent is not particularly limited, and one or more arbitrary solvents can be selected and used, but it is preferable to use the same solvent as that used in the subsequent condensation reaction.

[0032] After completion of the hydrolysis reaction, condensation is carried out using an acidic catalyst or a basic catalyst. For the condensation reaction, a conventionally known dehydration condensation catalyst can be arbitrarily used. In the case of using an acid catalyst, formic acid has high catalytic activity and can be shared as the catalyst for the hydrolysis reaction, so it is preferable. The reaction temperature and reaction time can be arbitrarily set according to the reactivity of component (a1) and component (a2), respectively. The reaction temperature is usually about 40°C or higher and 150°C or lower, preferably about 60°C or higher and 100°C or lower. The reaction time is about 30 minutes or longer and 12 hours or shorter.

[0033] When using a basic catalyst, after completion of the hydrolysis reaction, it is necessary to remove the acidic catalyst from the system, and this is removed by a method such as reduced pressure or filtration. Incidentally, simultaneously with the removal of the acidic catalyst, the alcohol by-produced and the excess water can be removed by a method such as reduced pressure. Further, by diluting with the solvent used in the subsequent condensation reaction after removal, it is also possible to make it easier to add the hydrolysis reaction product in the subsequent condensation reaction.

[0034] In the condensation reaction, water is by-produced between the above-mentioned silanol groups, and alcohol is by-produced between the silanol group and the alkoxy group to form a siloxane bond. As the condensation reaction, a basic catalyst that can function as a conventionally known dehydration condensation catalyst can be arbitrarily used. Among them, those with high basicity are preferable. Specific examples include alkali salts such as sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)₂), organic amines such as 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]nona-5-ene, and ammonium hydroxides such as tetramethylammonium hydroxide and tetrabutylammonium hydroxide. Any of the above-exemplified compounds can be used alone or in an appropriate combination. Among the above-exemplified compounds, tetramethylammonium hydroxide is particularly preferable because of its high catalytic activity and easy availability. Further, when these basic catalysts are used as an aqueous solution, since the hydrolysis reaction also proceeds in the condensation reaction step, it is necessary to appropriately adjust, such as reducing in advance the amount of water used during hydrolysis by the amount of water contained in the basic catalyst.

[0035] The addition amount of the basic catalyst is preferably 0.01 part by mass or more and 5 parts by mass or less, and more preferably 0.1 part by mass or more and 2 parts by mass or less with respect to 100 parts by mass in total of the components (a1) and (a2). When the addition amount exceeds 5 parts by mass, the cured product produced using the obtained component (A) tends to be easily colored, the catalyst cannot be completely removed when removing the catalyst, or the step of removing the catalyst becomes long. On the other hand, when the addition amount is less than 0.01 part by mass, the reaction does not substantially proceed or the reaction time tends to be long.

[0036] The reaction temperature can be arbitrarily set according to the reactivity of component (a1) and component (a2), respectively. The reaction temperature is usually about 40°C or higher and 150°C or lower, preferably about 60°C or higher and 100°C or lower. The condensation reaction is carried out in the presence of a polar solvent. When the reaction is carried out in a non-polar solvent, it is not preferable because the silanol group may not be completely consumed or the system may gel due to abnormal high molecular weight increase. As the polar solvent, a polar solvent showing compatibility with water is preferable, and glycol ethers are particularly preferable. Among glycol ethers, dialkyl glycol ether-based solvents are particularly preferable because abnormal high molecular weight increase as described above hardly occurs. Examples of the dialkyl glycol ether-based solvent showing compatibility with water include ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, and the like.

[0037] The above condensation reaction is carried out by a method in which a solution containing a hydrolyzate obtained by a hydrolysis reaction is sequentially added to a polar solvent set at a reaction temperature and added with a dehydration condensation catalyst. The addition method can be appropriately selected from various known methods. The time required for the addition can be arbitrarily set according to the reactivity of component (a1) and component (a2), respectively, but is usually about 30 minutes or longer and 12 hours or shorter.

[0038] The above condensation reaction is preferably carried out by diluting with a solvent so that the concentration of component (a1) (both when component (a2) is used in combination) in the reaction solution is preferably about 2% by mass or higher and 80% by mass or lower, and more preferably by diluting with a solvent so that the above concentration is about 15% by mass or higher and 60% by mass or lower. Using a solvent having a boiling point higher than the boiling points of water and alcohol generated by the condensation reaction is preferable because these can be distilled off from the reaction system. When the above concentration is less than 2% by mass, the content of component (A) contained in the obtained negative-type radiation-sensitive resin composition tends to be small. When the above concentration exceeds 80% by mass, gelation tends to occur during the reaction or the molecular weight of the generated component (A) tends to become too large.

[0039] After completion of the condensation reaction, removing the catalyst used is preferable because the stability of the component (A) or the negative-type radiation-sensitive resin composition containing the component (A) is improved. The method for removing the catalyst can be appropriately selected from various known methods according to the catalyst used. For example, when using tetramethylammonium hydroxide, it can be removed by a method such as adsorption and removal with a cation exchange resin after completion of the condensation reaction.

[0040] The component (A) may be used alone or in combination of two or more.

[0041] (B) Polyfunctional methacrylate The carbon-carbon double bond possessed by the component (B) reacts with the thiol group of the component (A) (ene-thiol reaction), and this reaction mechanism varies depending on the type of the carbon-carbon double bond and the presence or absence of a radical polymerization initiator.

[0042] In the present embodiment, from the viewpoints of improving the storage stability of the negative-type radiation-sensitive resin composition and controlling the curability of the obtained insulating film, a compound having two or more methacrylate groups in one molecule is preferably used.

[0043] Specific examples of such polyfunctional methacrylates include polyfunctional methacrylic acid esters such as bifunctional methacrylic acid esters and trifunctional or higher methacrylic acid esters.

[0044] Examples of the bifunctional methacrylic acid ester include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, and the like.

[0045] Examples of the methacrylic acid ester having three or more functional groups include trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol pentamethacrylate, ditrimethylolpropane tetramethacrylate, a mixture of dipentaerythritol pentamethacrylate and dipentaerythritol hexamethacrylate, dipentaerythritol hexamethacrylate, ethylene oxide-modified dipentaerythritol hexamethacrylate, tri(2-methacryloyloxyethyl) phosphate, succinic acid-modified dipentaerythritol pentamethacrylate, and the like. In addition, there are also examples of polyfunctional urethane methacrylate compounds obtained by reacting a compound having a linear alkylene group and an alicyclic structure and having two or more isocyanate groups with a compound having one or more hydroxy groups in the molecule and having three, four, or five methacryloyloxy groups. Among these, from the viewpoints of improving storage stability and the curability of the resulting insulating film, as the methacrylic acid ester having four or more functional groups, pentaerythritol tetramethacrylate, trimethylolpropane trimethacrylate, or ditrimethylolpropane tetramethacrylate is preferable, and pentaerythritol tetramethacrylate or ditrimethylolpropane tetramethacrylate is more preferable.

[0046] Regarding the content ratio of component (B), the mass ratio of component (B) to component (A) is preferably 1 / 2 or more and 2 / 1 or less. In particular, when component (B) is a methacrylate having four or more functional groups, the mass ratio of component (B) to component (A) is preferably 1 / 2 or more and 2 / 1 or less. In these cases, specifically, as the lower limit of the content ratio of component (B), 20 parts by mass is preferable, and 50 parts by mass is more preferable with respect to 100 parts by mass of component (A). On the other hand, as the upper limit of the content ratio of component (B), 200 parts by mass is preferable, and 150 parts by mass is more preferable with respect to 100 parts by mass of component (A). By the content ratio of component (B) to component (A) being within the above range, various properties of the resulting insulating film can be more effectively enhanced.

[0047] (Component (B) may be used alone or in combination of two or more components.)

[0048] (C) Photoinitiator (Component (C) is a compound that can generate radicals upon exposure to radiation and initiate polymerization, i.e., a photo radical polymerization initiator.) Specific examples of (C) photoinitiators include, for example, O - acyloxime compounds, α - aminoketone compounds, α - hydroxyketone compounds, acylphosphine oxide compounds, etc.)

[0049] Examples of the O-acyl oxime compounds include 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethan-1-one oxime-O-acetate, 1-[9-ethyl-6-benzoyl-9H-carbazol-3-yl]-octan-1-one oxime-O-acetate, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethan-1-one oxime-O-benzoate, 1-[9-n-butyl-6-(2-ethylbenzoyl)-9H-carbazol-3-yl]-ethan-1-one oxime-O-benzoate, ethanone, 1-[9-ethyl-6-(2-methyl-4-tetrahydrofuranylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime), ethanone, 1-[9-ethyl-6-(2-methyl-4-tetrahydropyranylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime), ethanone, 1-[9-ethyl-6-(2-methyl-5-tetrahydrofuranylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime), ethanone, 1-[9-ethyl-6-{2-methyl-4-(2,2-dimethyl-1,3-dioxolanyl)methoxybenzoyl}-9H-carbazol-3-yl]-, 1-(O-acetyl oxime), ethanone, 1-[9-ethyl-6-(2-methyl-4-tetrahydrofuranylmethoxybenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime), 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyl oxime)], and the like.

[0050] Examples of the α-aminoketone compound include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone, 1-[4-(2-hydroxyethylsulfanyl)phenyl]-2-methyl-2-(4-morpholino)propan-1-one, and the like.

[0051] Examples of the α-hydroxyketone compound include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-(4-i-propylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, and the like.

[0052] Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and the like.

[0053] (C) From the viewpoint of further promoting the curing reaction by radiation, O-acyl oxime compounds, α-aminoketone compounds, and acylphosphine oxide compounds are preferred as the photopolymerization initiator, O-acyl oxime compounds and α-aminoketone compounds are more preferred, and O-acyl oxime compounds are even more preferred.

[0054] Oxime-based photoinitiators such as O-acyl oxime compounds generate radicals such as phenyl radicals and methyl radicals when irradiated with light, and polymerization proceeds preferably by these radicals. Among such oxime-based photoinitiators, oxime-based photoinitiators that generate methyl radicals are preferable in that the initiation efficiency of the polymerization reaction is high. Further, from the viewpoint of making the polymerization reaction proceed more efficiently, it is preferable to use a photoinitiator that can efficiently utilize ultraviolet light having a wavelength of 350 nm or more. Examples of such an oxime ester-based polymerization initiator that generates methyl radicals include compounds having a structure represented by the following formula (1).

[0055]

Chemical formula

[0056] In the above formula (1), * indicates the bonding site with other parts in the above compound.

[0057] Applying an oxime ester-based photoinitiator that generates methyl radicals is preferable because it has excellent curability, developability resistance, an effect of suppressing the occurrence of pattern chipping, and excellent cured film physical properties even under low-temperature curing conditions.

[0058] Examples of oxime ester photopolymerization initiators that generate alkyl radicals including methyl radicals include ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (trade name: Irgacure OXE-02, manufactured by BASF), methanone, [8-[[(acetyloxy)imino][2-(2,2,3,3-tetrafluoropropoxy)phenyl]methyl]-11-(2-ethylhexyl)-11H-benzo[a]carbazol-5-yl]-, (2,4,6-trimethylphenyl) (trade name: Irgacure OXE-03, manufactured by BASF), ethanone, 1-[9-ethyl-6-(1,3-dioxolane, 4-(2-methoxyphenoxy)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (trade name: ADEKA OPT-N-1919, manufactured by ADEKA), methanone, (9-ethyl-6-nitro-9H-carbazol-3-yl) [4-(2-methoxy-1-methylethoxy-2-methylphenyl]-, o-acetyloxime (trade name ADEKA Arcles NCI-831, manufactured by ADEKA), 1-propanone, 3-cyclopentyl-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (trade name TR-PBG-304, manufactured by Changzhou Strong Electronic New Materials Co., Ltd.), 1-propanone, 3-cyclopentyl-1-[2-(2-pyrimidinylthio)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (trade name TR-PBG -314, Changzhou Powerful Electronic New Materials Co., Ltd.), ethanone, 2-cyclohexyl-1-[2-(2-pyrimidinyloxy)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (trade name TR-PBG-326, Changzhou Powerful Electronic New Materials Co., Ltd.), ethanone, 2-cyclohexyl-1-[2-(2-pyrimidinylthio)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (trade name TR-PBG-331, Changzhou Powerful Electronic New Materials Co., Ltd.), 1-octanone, 1-[4-[3-[1-[(acetyloxy)imino]ethyl]-6-[4-[(4,6-dimethyl-2-pyrimidinyl)thio]-2-methylbenzoyl]-9H-carbazol-9-yl]phenyl]-,Examples include 1-(o-acetyloxime) (trade name: EXTA-9, manufactured by Union Chemical).

[0059] In addition, a photopolymerization initiator having a tertiary amine structure may be combined with the oxime ester-based photopolymerization initiator and used. This is because the photopolymerization initiator having a tertiary amine structure has a tertiary amine structure which is an oxygen quencher in the molecule, so that the radicals generated from the initiator are less likely to be deactivated by oxygen, and the sensitivity can be improved. Commercially available products of the photopolymerization initiator having the above-mentioned tertiary amine structure include, for example, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (for example, Irgacure 907, manufactured by BASF), 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone (for example, Irgacure 369, manufactured by BASF), 4,4'-bis(diethylamino)benzophenone (for example, Highcure ABP, manufactured by Kawaguchi Pharmaceutical), and the like.

[0060] As described above, the component (C) can be used alone or in admixture of two or more. The content ratio of the component (C) is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 5 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the component (A). When the above content ratio is 1 part by mass or more and 40 parts by mass or less, the negative-type radiation-sensitive resin composition can form a cured film having high solvent resistance, high hardness and high adhesion even at a low exposure amount. As a result, an insulating film having more excellent properties in these respects is provided.

[0061] (F) Organic solvent The negative-type radiation-sensitive resin composition may further contain an (F) organic solvent. The (F) organic solvent is not particularly limited, and examples thereof include alcohol solvents, ether solvents, ester solvents, ketone solvents, amide solvents, and the like. The (F) organic solvent may be used alone or in combination of two or more.

[0062] Examples of the alcohol solvents include alkyl alcohols such as methanol, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, t-butyl alcohol, 1-hexanol, 1-octanol, 1-nonanol, 1-dodecanol, 1-methoxy-2-propanol, and diacetone alcohol; and aromatic alcohols such as benzyl alcohol.

[0063] Examples of the ether solvents include ethylene glycol monoalkyl ethers such as diethylene glycol methyl ethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether; diethylene glycol monoalkyl ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether and diethylene glycol ethyl methyl ether; and dipropylene glycol monoalkyl ethers such as dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, and dipropylene glycol monobutyl ether.

[0064] Examples of the ester solvents include carboxylic acid esters such as ethyl acetate, i-propyl acetate, n-butyl acetate, amyl acetate, ethyl lactate, methyl 3-methoxypropionate, and ethyl 3-ethoxypropionate; polyhydric alcohol carboxylate solvents such as propylene glycol diacetate; and polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate.

[0065] Examples of the ketone solvents include acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl amyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, cycloheptanone, and the like.

[0066] Among these, ether solvents and ester solvents are preferred, ester solvents are more preferred, and polyhydric alcohol partial ether carboxylate solvents are even more preferred. Also, among the ether solvents and ester solvents, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, and methyl 3-methoxypropionate are preferred.

[0067] The content of the (F) organic solvent in the negative radiation-sensitive resin composition is not particularly limited, but it is preferably adjusted so that the solid content (components other than the (F) organic solvent) concentration is within the following range. As the lower limit of the solid content concentration in the negative radiation-sensitive resin composition, 5% by mass is preferred, 10% by mass is more preferred, and 20% by mass is even more preferred. On the other hand, as the upper limit of this solid content concentration, 60% by mass is preferred, 50% by mass is more preferred, and 40% by mass is even more preferred.

[0068] (D) Ultraviolet absorber The negative radiation-sensitive resin composition can further contain a (D) ultraviolet absorber (hereinafter also referred to as the "(D) component"). The (D) component is added for the purpose of controlling the photocuring distribution by absorbing a specific wavelength of the light source used for exposure with the (D) component. When the negative radiation-sensitive resin composition contains the (D) component, effects such as improving the taper angle shape after development and reducing the residue remaining in the unexposed portion after development tend to be obtained. As the (D) component, from the viewpoint of inhibiting the light absorption by the (C) component, for example, a compound having an absorption maximum between 250 nm and 400 nm in wavelength can be used.

[0069] Examples of component (D) include benzotriazole compounds, triazine compounds, benzophenone compounds, benzoate compounds, cinnamic acid derivatives, naphthalene derivatives, anthracene and its derivatives, dinaphthalene compounds, phenanthroline compounds, dyes, and the like.

[0070] Component (D) can be used alone or in combination of two or more.

[0071] Among these, from the viewpoint of increasing the taper angle, benzotriazole compounds and / or hydroxyphenyltriazine compounds are preferred, and benzotriazole compounds are particularly preferred. Specifically, examples of benzotriazole compounds include 2-(5-t-butyl-2-hydroxyphenyl)benzotriazole, 2,2-methylenebis{6-(benzotriazol-2-yl-4-tert-octylphenol)}, and the like. Examples of benzophenone-based organic compounds include 2,2-dihydroxy-4,4-dimethoxybenzophenone, and the like. Examples of triazine-based organic compounds include 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine, and the like. Commercially available products include "TINUVIN PS", "TINUVIN P", "TINUVIN 324", "TINUVIN 326", "TINUVIN 360" manufactured by BASF, "Sisorb 107" manufactured by Cipro Kasei Co., Ltd., "ADEKA STAB LA-F70" manufactured by ADEKA Corporation, and the like.

[0072] The content ratio of component (D) is preferably 0.1 part by mass or more and 30 parts by mass or less, more preferably 1 part by mass or more and 30 parts by mass or less, further preferably 10 parts by mass or more and 30 parts by mass or less, and even more preferably 20 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of component (A). By satisfying the above content ratio within the above range, the shape and resolution of the obtained pattern are improved.

[0073] (E) Base generator The negative-type radiation-sensitive resin composition may further contain (E) a base generator (hereinafter also referred to as “component (E)”).

[0074] (E) The base generator is not particularly limited as long as it is a compound that generates a base (such as an amine) upon irradiation with radiation. Examples of the (E) base generator include transition metal complexes such as cobalt, ortho-nitrobenzyl carbamates, α,α-dimethyl-3,5-dimethoxybenzyl carbamates, acyloxyimines, and the like.

[0075] Examples of the above-mentioned transition metal complexes include bromopentamminecobalt perchlorate, bromopentamethylaminecobalt perchlorate, bromopentapropylaminecobalt perchlorate, hexaamminecobalt perchlorate, hexamethylaminecobalt perchlorate, hexapropylaminecobalt perchlorate, and the like.

[0076] Examples of the ortho-nitrobenzyl carbamates include [[(2-nitrobenzyl)oxy]carbonyl]methylamine, [[(2-nitrobenzyl)oxy]carbonyl]propylamine, [[(2-nitrobenzyl)oxy]carbonyl]hexylamine, [[(2-nitrobenzyl)oxy]carbonyl]cyclohexylamine, and the like.

[0077] Examples of the α,α-dimethyl-3,5-dimethoxybenzyl carbamates include [[(α,α-dimethyl-3,5-dimethoxybenzyl)oxy]carbonyl]methylamine, [[(α,α-dimethyl-3,5-dimethoxybenzyl)oxy]carbonyl]propylamine, and the like.

[0078] Examples of the acyloxyimines include propionylacetophenone oxime, propionylbenzophenone oxime, propionylacetone oxime, butyrylacetophenone oxime, butyrylbenzophenone oxime, butyrylacetone oxime, adipoylacetophenone oxime, adipoylbenzophenone oxime, and the like.

[0079] Other examples of base generators other than those described above include 2-nitrobenzyl cyclohexylcarbamate, O-carbamoylhydroxyamide, and O-carbamoylhydroxyamide 1,2-diisopropyl-3-{bis(dimethylamino)methylene}guanidinium = 2-(3-benzoylphenyl)propionate.

[0080] (E) The base generator may be used alone or in combination of two or more.

[0081] (E) As the lower limit of the content ratio of the base generator, 0.1 part by mass is preferable and 1 part by mass is more preferable with respect to 100 parts by mass of the component (A). As the upper limit of the content ratio of the base generator, 20 parts by mass is preferable and 10 parts by mass is more preferable with respect to 100 parts by mass of the component (A). By satisfying the above content ratio within the above range, the obtained pattern shape and heat resistance become good at a high level.

[0082] (Other components) The negative-type radiation-sensitive resin composition may further contain other components other than the above-described components (A), (B), (C), (D), (E), and (F) organic solvent. Examples of such other components include curing agents, curing accelerators, adhesion aids, antioxidants, surfactants, and the like. However, the content of other components other than the components (A), (B), (C), (D), (E), and (F) organic solvent in the negative-type radiation-sensitive resin composition may be preferably 10% by mass or less, and more preferably 1% by mass or less.

[0083] (Viscosity of negative-type radiation-sensitive resin composition) Using an E-type viscometer, the viscosity of the negative-type radiation-sensitive resin composition measured under the conditions of 25°C and 50 rpm is preferably 0.5 mPa·s or more and 20 mPa·s or less, more preferably 0.5 mPa·s or more and 7 mPa·s or less, and even more preferably 2.5 mPa·s or more and 5 mPa·s or less. By satisfying the above viscosity within the above range, it is excellent in all of the resolution, residual film ratio, chemical resistance, oxygen ashing resistance, and storage stability described below. The viscosity of the negative-type radiation-sensitive resin composition can be set within the above range by adjusting the amount of the (F) organic solvent to be added.

[0084] <Formation temperature of the cured film> As described above, the negative-type radiation-sensitive resin composition can obtain a cured film having sufficient etching chemical resistance and oxygen ashing resistance even by heating at a relatively low temperature. The negative-type radiation-sensitive resin composition is preferably a composition that can be cured by heating in a temperature range of, for example, 60°C or more and 120°C or less, and more preferably a composition that can be cured by heating in a temperature range of 60°C or more and 100°C or less.

[0085] <Method for preparing a negative-type radiation-sensitive resin composition> The negative-type radiation-sensitive resin composition can be prepared by mixing each component at a predetermined ratio and dissolving it in the (F) organic solvent. The prepared composition is preferably filtered, for example, with a filter having a pore size of about 0.2 μm.

[0086] <Insulating film for organic EL element> The insulating film for an organic EL element according to one embodiment of the present invention is a cured film formed from the negative-type radiation-sensitive resin composition. The insulating film for an organic EL element may be a patterned film. Since the insulating film for an organic EL element is formed from a negative-type radiation-sensitive resin composition that can obtain a cured film having sufficient etching chemical resistance and oxygen ashing resistance even by heating at a relatively low temperature, the yield is high and the durability and the like are also excellent.

[0087] The insulating film for the organic EL element is suitable as an interlayer insulating film, and may also be used for a planarizing film, a spacer, a protective film, etc. The insulating film for the organic EL element can also be used in a display device (organic EL device) including the organic EL element, a display device such as an electronic paper, etc. Further, as will be described later, the insulating film for the organic EL element is suitable as an interlayer insulating film between a touch panel and another layer in a display device including a touch panel, such as an organic EL device including a touch panel.

[0088] Even when the insulating film for the organic EL element is relatively thick, generation of cracks is less likely to occur. Therefore, the insulating film for the display device can be thickened. As the lower limit of the average thickness of the insulating film for the organic EL element, for example, it may be 0.1 μm, but 0.5 μm is preferable, 1 μm is more preferable, and 2 μm may be even more preferable. On the other hand, as the upper limit of this average thickness, for example, it is 10 μm, and it may be 6 μm or 4 μm.

[0089] The above-described insulating film for the organic EL element can be provided in various display devices. Examples of such display devices include an organic EL device, an electronic paper, etc., and among these, an organic EL device is preferable.

[0090] <organic EL device> The organic EL device according to an embodiment of the present invention includes the above-described insulating film for the organic EL element. The organic EL device preferably includes a touch panel laminated on a substrate having an organic EL element. The organic EL element usually has a laminated structure including an anode layer, an organic light-emitting layer, and a cathode layer. It is preferable that the insulating film for the organic EL element is used for at least a part of the insulating film in the touch panel. In particular, it is preferable that the insulating film for the organic EL element is used for the insulating film of the touch panel laminated on the substrate having the organic EL element without an adhesive layer or an adhesive layer in between. By doing so, since the touch panel can be directly laminated on the substrate on which the organic EL element is formed, thinning of the organic EL device including the touch panel becomes possible.

[0091] Since the negative-type radiation-sensitive resin composition can obtain a cured film having sufficient etching chemical resistance and oxygen ashing resistance even by heating at a relatively low temperature, it is possible to suppress the deterioration of the organic EL element in the manufacturing process of the organic EL device, and improve the yield. Further, since the deterioration of the organic EL element in the above manufacturing process can be suppressed by forming an insulating film by heating at a relatively low temperature using the negative-type radiation-sensitive resin composition, the negative-type radiation-sensitive resin composition can be particularly preferably used for forming an insulating film in various organic EL devices including an organic EL element other than the organic EL device provided with a touch panel.

[0092] FIG. 1 shows one form of an organic EL device provided with a touch panel. The organic EL device 10 with a touch panel in FIG. 1 includes an organic EL display substrate 20 and a touch panel 30. The organic EL display substrate 20 has a structure in which a support substrate 21, an anode layer 22, an organic light-emitting layer 23, a cathode layer 24, an adhesive layer 25, and a sealing substrate 26 are laminated in this order. At least the anode layer 22, the organic light-emitting layer 23, and the cathode layer 24 constitute an organic EL element. As the organic light-emitting layer 23, for example, a structure in which a hole injection layer, a hole transport layer, an organic EL light-emitting layer, an electron transport layer, and an electron injection layer are laminated in this order from the anode layer 22 side can be adopted.

[0093] The touch panel 30 is a capacitance type in which a first sensor electrode 31, an insulating film 33, and a second sensor electrode 32 are laminated in this order. The touch panel 30 has a first sensor electrode 31, a second sensor electrode 32 disposed opposite to the first sensor electrode 31, an insulating film 33, and a transparent substrate 34 disposed on the outermost surface. In the present embodiment, the first sensor electrode 31 is formed directly on the sealing substrate 26 of the organic EL display substrate 20. The insulating film 33 is a transparent insulating film that insulates the first sensor electrode 31 and the second sensor electrode 32, and is formed from the negative-type radiation-sensitive resin composition. The touch panel is not limited to such a capacitance type.

[0094] <Method for forming an insulating film for an organic EL element> A method for forming an insulating film for an organic EL element according to an embodiment of the present invention includes a step of forming a coating film by applying the above-described negative radiation-sensitive resin composition directly or indirectly on a substrate (hereinafter, also referred to as "coating film forming step"), a step of irradiating (exposing) radiation to at least a part of the coating film after the step of forming the coating film (hereinafter, also referred to as "radiation irradiation step"), a step of developing the coating film after the step of irradiating the radiation (hereinafter, also referred to as "development step"), and a step of heating the coating film at a temperature of 60°C or higher and 120°C or lower after the step of developing (hereinafter, also referred to as "heating step"). As an optional step, the forming method may include a step of heating the coating film (hereinafter, also referred to as "PEB step") between the radiation irradiation step and the development step.

[0095] According to the forming method, since the above-described negative radiation-sensitive resin composition is used, patterning can be performed into a good shape, and an insulating film having sufficient etching chemical resistance and oxygen ashing resistance can be obtained even by heating at a relatively low temperature. Further, even when the substrate on which the coating film is formed includes an organic EL element, deterioration of the organic EL element can be suppressed by performing the heating step at a relatively low temperature. Hereinafter, each step will be described.

[0096] (Coating Film Forming Step) In this step, after applying the negative radiation-sensitive resin composition directly on the substrate or through another layer, preferably, the coating surface is heated (pre-baked) to remove an organic solvent or the like, thereby forming a coating film. Examples of the material of the substrate include glass, quartz, silicon, resin, and the like. Specific examples of the resin include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, polyimide, an addition polymer of cyclic olefin, a ring-opening polymer of cyclic olefin, and a hydrogenated product thereof.

[0097] The above substrate may include an organic EL element or the like. Further, the above substrate may have electrodes, wirings, etc. provided on the coating surface. As such a substrate, in FIG. 1 described above, the organic EL display substrate 20 on which the first sensor electrode 31 is formed can be exemplified.

[0098] The coating method of the negative-type radiation-sensitive resin composition is not particularly limited, and for example, appropriate methods such as a spray method, a roll coating method, a spin coating method (spin coat method), a slit die coating method, a bar coating method, etc. can be adopted. Among these coating methods, the spin coating method and the slit die coating method are particularly preferred. The pre-baking conditions vary depending on the type of each component, the blending ratio, etc., but for example, the heating time may be 1 minute or more and 10 minutes or less at a temperature of 60°C or higher and 120°C or lower, more preferably 100°C or lower.

[0099] (Radiation irradiation step) In this step, at least a part of the coating film formed in the coating film forming step is irradiated with radiation. Usually, when irradiating a part of the coating film with radiation, it is irradiated through a photomask having a predetermined pattern. As the above radiation, for example, visible light, ultraviolet light, far ultraviolet light, electron beam, X-ray, etc. can be used. Among these radiations, radiation having a wavelength in the range of 190 nm or more and 450 nm or less is preferred, and radiation including ultraviolet light of 365 nm is more preferred.

[0100] As the lower limit of the exposure amount in this step, as the value measured by an illuminometer ("OAI model356" of OAI Optical Associates Inc.) for the intensity at a radiation wavelength of 365 nm, 10 mJ / cm 2 is preferred, and 50 mJ / cm 2 is more preferred. Also, as the upper limit of the above exposure amount, as the value measured by the above illuminometer, 2,000 mJ / cm 2 is preferred, and 1,000 mJ / cm 2 is more preferred.

[0101] (PEB step) When providing a PEB process, the PEB conditions vary depending on the type and blending ratio of each component. For example, the heating temperature may be 60°C or higher and 120°C or lower, more preferably 100°C or lower, and the heating time may be 1 minute or longer and 10 minutes or shorter.

[0102] (Development process) In this process, a predetermined pattern is formed by developing the radiation-exposed coating film with a developer. An alkaline developer is preferably used as the developer. Examples of the alkaline developer include an alkaline aqueous solution in which at least one alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, tetramethylammonium hydroxide, and tetraethylammonium hydroxide is dissolved. In addition, an appropriate amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant may be added to the alkaline developer.

[0103] As the development method, for example, an appropriate method such as a puddle method, a dipping method, a rocking immersion method, or a spray method can be adopted. The development time varies depending on the composition of the radiation-sensitive composition, but is, for example, 10 seconds or longer and 180 seconds or shorter. Following such development treatment, for example, running water washing is performed for a treatment time of 30 seconds or longer and 90 seconds or shorter, and then, for example, air drying with compressed air or compressed nitrogen can form a desired pattern.

[0104] (Heating process) In this process, the developed and patterned coating film is heated (post-baked) using a heating device such as a hot plate or an oven to obtain an insulating film for a display device having a desired pattern. Note that between the development process and the heating process, the coating film may be irradiated with radiation such as ultraviolet rays. The exposure amount at this time is, for example, 100 mJ / cm 2 or more and 2,000 mJ / cm 2The following can be adopted. The lower limit of the heating temperature is 60°C, and 80°C is preferable. By setting the heating temperature to be equal to or higher than the above lower limit, a sufficiently cured insulating film can be obtained. On the other hand, the upper limit of the heating temperature is 120°C, and 100°C is preferable. By setting the heating temperature to be equal to or higher than the above lower limit, for example, while suppressing the deterioration of the organic EL element provided on the substrate, a sufficiently cured insulating film can be obtained. Also, by setting the heating temperature to be equal to or lower than the above upper limit, excessive stress generation such as rapid film shrinkage can be suppressed, and thus the generation of cracks can be suppressed. Thus, in the heating step, heating is performed in the temperature range of 60°C or higher and 120°C or lower. The heating time varies depending on the type of heating equipment. For example, when heating on a hot plate, it may be 5 minutes or more and 30 minutes or less, and when heating in an oven, it may be 10 minutes or more and 90 minutes or less. Note that the heating may be performed in air or in an inert gas atmosphere such as nitrogen or argon. Also, it is possible to use a step-bake method in which the heating step is performed two or more times.

[0105] (Other steps) When manufacturing the organic EL device, after forming the insulating film for the organic EL element on the organic EL display substrate, other steps such as forming further electrodes, wirings, etc. (for example, the second sensor electrode 32 in the touch panel 30 of FIG. 1) are performed. Examples of such steps include an electrode formation step, a wiring formation step, an etching step, an ashing step, etc. For the formation of electrodes and wirings, known methods such as printing and vapor deposition can be adopted. Etching can be performed using a known etching chemical solution such as an amine-based solution. Ashing can be performed by a known ashing method such as oxygen ashing. Note that when manufacturing a touch panel or the like, the formation of the insulating film and the formation of electrodes, wirings, etc. may each be performed a plurality of times.

Examples

[0106] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

[0107] (Measurement of weight average molecular weight (Mw)) In the following synthesis examples of polymers, the weight-average molecular weight (Mw) of the obtained polymers was measured by gel permeation chromatography (GPC) under the following conditions. Apparatus: "GPC-101" manufactured by Showa Denko KK Column: A combination of "GPC-KF-801", "GPC-KF-802", "GPC-KF-803" and "GPC-KF-804" manufactured by Showa Denko KK Mobile phase: Tetrahydrofuran Column temperature: 40 °C Flow rate: 1.0 mL / min Sample concentration: 1.0 mass% Sample injection volume: 100 μL Detector: Differential refractometer Standard substance: Monodisperse polystyrene

[0108] <Viscosity measurement> The viscosity was measured at 25 °C using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) in accordance with JIS K2283:2000.

[0109] The following shows a synthesis example of a thiol group-containing polysiloxane as the component (A). Unless otherwise specified below, "%" means "mass%".

[0110] [Synthesis Example 1] (Production of a thiol group-containing polysiloxane solution (A-1)) Into a reactor equipped with a stirrer, a cooling pipe, a water separator, a thermometer, and a nitrogen inlet, 190 g of 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.; trade name "KBM-803") as component (a1), 52.3 g of ion-exchanged water ([number of moles of water used in the hydrolysis reaction] / [number of moles of alkoxy groups contained in component (a1)] (molar ratio) = 1.0), and 9.5 g of 95% formic acid were charged, and a hydrolysis reaction was carried out at room temperature for 30 minutes. During the reaction, the temperature increased by a maximum of 22 °C due to exotherm. After the reaction, 287.36 g of propylene glycol monomethyl ether acetate was charged and heated. When the temperature was raised to 82 °C, methanol generated by hydrolysis began to be distilled off. Subsequently, the temperature was raised to 105 °C over 30 minutes, and water generated by the condensation reaction was distilled off. After reacting at 105 °C for another 1 hour and 30 minutes, the pressure was reduced to 70 °C - 150 mmHg to distill off a part of the remaining methanol, water, formic acid, and propylene glycol monomethyl ether acetate, thereby obtaining 385.2 g of a condensate solution (A-1). In the thiol group-containing polysiloxane ((A-1) component) contained in the condensate solution (A-1), [total number of moles of unreacted hydroxyl groups and unreacted alkoxy groups] / [number of moles of alkoxy groups contained in component (a1)] (molar ratio) was 0.15, and the concentration was 32.0%. Also, the thiol equivalent of the condensate solution (A-1) was 398 g / eq, and Mw was 2147.

[0111] [Synthesis Example 2] (Production of thiol group-containing polysiloxane solution (A-2)) A reactor equipped with a stirrer, a cooling pipe, a water separator, a thermometer, a dropping funnel, and a nitrogen inlet was charged with 300 g of 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.; trade name "KBM-803") as component (a1), 162.8 g of ion-exchanged water ([the number of moles of water used in the hydrolysis reaction] / [the number of moles of alkoxy groups contained in component (a1)] (molar ratio) = 2.0), and 6.0 g of a cation-exchange resin (manufactured by Mitsubishi Chemical Corporation; trade name "Diaion PK228LH", H-type strongly acidic cation-exchange resin), and a hydrolysis reaction was carried out at room temperature for 30 minutes. During the reaction, the temperature increased by a maximum of 28 °C due to heat generation. After the reaction, the cation-exchange resin was filtered off, and then, by reducing the pressure at 70 °C and 20 kPa for 3 hours, 228 g of a hydrolyzate was obtained. This was diluted with 82 g of ethylene glycol dimethyl ether to obtain 310 g of a hydrolyzate solution.

[0112] Subsequently, 325.9 g of ethylene glycol dimethyl ether and 1.25 g of a 25% aqueous solution of tetramethylammonium hydroxide were charged into another reaction vessel and heated to 80 °C. Tetramethylammonium hydroxide did not dissolve in ethylene glycol dimethyl ether and appeared slightly turbid. 300 g of the hydrolyzate solution obtained above was added dropwise thereto over 2 hours and 30 minutes. During the dropping, tetramethylammonium hydroxide dissolved and the reaction solution became clear. After the dropping, the reaction was continued at 80 °C for 15 minutes and then cooled to 25 °C. At 25 °C, tetramethylammonium hydroxide did not dissolve and the reaction solution appeared slightly turbid. 6.4 g of the same cation-exchange resin as above was charged thereto and stirred at room temperature for 4 hours. During the stirring, tetramethylammonium hydroxide was adsorbed onto the cation-exchange resin and the reaction solution became clear. After filtering off the cation-exchange resin, by reducing the pressure at 70 °C and 20 kPa for 2 hours and further at 70 °C and 0.7 kPa for 1 hour, 196 g of a thiol group-containing polysiloxane solution (A-2) was obtained. When the thiol group-containing polysiloxane ((A-2) component) contained in the solution (A-2) was analyzed by infrared spectroscopy, at 3500 cm -1There was no absorption of silanol groups observed in the vicinity. Also, in the analysis by nuclear magnetic resonance method, no silanol groups were found. In the (A-2) component, the molar ratio of [total number of moles of unreacted hydroxyl groups and unreacted alkoxy groups] / [number of moles of alkoxy groups contained in component (a1)] was 0. Also, the concentration of the (A-2) component in solution (A-2) was 94.7%, the thiol equivalent was 133 g / eq, and Mw was 2700.

[0113] [Preparation of Negative-Type Radiation-Sensitive Resin Composition] The raw materials used for preparing each negative-type radiation-sensitive resin composition are shown below.

[0114] (Component (A)) A-1: Thiol group-containing polysiloxane obtained in Synthesis Example 1 A-2: Thiol group-containing polysiloxane obtained in Synthesis Example 2 A-3: Thiol group-containing polysiloxane (Composylan SQ109 manufactured by Arakawa Chemical Industries, Ltd.)

[0115] (Comparative Component (a)) a-1: Pentaerythritol tetrakis(3-mercaptopropionate) (PEMP)

[0116] (Component (B)) B-1: Pentaerythritol tetramethacrylate B-2: Ditrimethylolpropane tetramethacrylate B-3: Trimethylolpropane trimethacrylate (Comparative Component (b)) b-1: Dipentaerythritol hexaacrylate (DPHA)

[0117] (Component (C)) C-1: 1,2-Octanedione, 1-{4-(phenylthio)phenyl}-, 2-(O-benzoyloxime) (IRGACURE OXE-01 manufactured by BASF) C-2: NCI-930 (manufactured by ADEKA) C-3: 2-Methyl-1-{4-(methylthio)phenyl}-2-morpholinopropan-1-one (IRGACURE 907 manufactured by BASF)

[0118] (Component (D)) D-1: Tinuvin PS (manufactured by BASF) D-2: Tinuvin 324 (manufactured by BASF)

[0119] (Component (E)) E-1: 1,2-Diisopropyl-3-{bis(dimethylamino)methylene}guanidinium = 2-(3-benzoylphenyl)propionate

[0120] (Organic solvent (F)) F-1: Propylene glycol monomethyl ether acetate (PGMEA)

[0121] The following shows preparation examples of the negative-type radiation-sensitive resin composition. In the following, unless otherwise specified, “%” means “mass %”.

[0122] (Example 1) 100 parts by mass of (A-1) as component (A) in the solution (A-1) obtained in Synthesis Example 1, 200 parts by mass of (B-1) as component (B), 15 parts by mass of (C-1) as component (C), and 20 parts by mass of (D-2) as component (D) were dissolved in 500 parts by mass of (F-1) as the (F) organic solvent to prepare the negative-type radiation-sensitive resin composition of Example 1. For the obtained negative-type radiation-sensitive resin composition, the viscosity measured using an E-type viscometer under the conditions of 25 °C and 50 rpm was 3.5 mPa·s. The results are shown in Table 1.

[0123] (Examples 2 to 11, Comparative Examples 1 to 2) Negative-type radiation-sensitive resin compositions of Examples 2 to 11 and Comparative Examples 1 to 2 were prepared in the same manner as in Example 1 except that the components of the types and contents shown in Table 1 were used, and the viscosity of the obtained negative-type radiation-sensitive resin compositions was measured in the same manner as in Example 1. The results are shown in Table 1.

[0124] [Evaluation] The negative-type radiation-sensitive resin composition obtained above was evaluated for resolution, residual film ratio, chemical resistance, oxygen ashing resistance, and storage stability according to the following methods. The results are shown in Table 1.

[0125] [Resolution] After applying the negative-type radiation-sensitive resin composition on a silicon substrate by spin coating, a coating film with a thickness of 2.5 μm was formed by pre-baking on a hot plate at 85°C for 2 minutes. For the obtained coating film, a high-pressure mercury lamp (exposure amount at 365 nm is 100 mJ / cm 2 ) was used, and after exposure through a mask in which square cut patterns with a side length of 10 μm were arranged at intervals of 10 μm, development was carried out by the liquid immersion method in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 25°C for 60 seconds. Then, after rinsing with ultrapure water for 60 seconds under running water, a pattern was formed on the silicon substrate by drying. The cross-sectional shape of the square cut pattern with a side length of 10 μm thus obtained was observed at a magnification of 1500 times using a scanning electron microscope (S-4200 manufactured by Hitachi, Ltd.). Those in which the pattern openings were formed without residue were evaluated as good and represented by "A", and those with residue in the pattern openings were evaluated as bad and represented by "B".

[0126] [Residual Film Ratio] After applying the negative-type radiation-sensitive resin composition on a silicon substrate by spin coating, a coating film with a thickness of 2.5 μm was formed by pre-baking on a hot plate at 85°C for 2 minutes. For the obtained coating film, a high-pressure mercury lamp (exposure amount at 365 nm is 100 mJ / cm 2After performing overall exposure using [specific item], development was carried out by the puddle method in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 25 °C for 60 seconds. Then, after rinsing with ultrapure water for 60 seconds under running water, a film was formed on the silicon substrate by drying. The average film thickness before and after development was measured, and the remaining film ratio (remaining film ratio before and after development) was calculated based on the following formula (1). This remaining film ratio was evaluated according to the following criteria. That is, when the remaining film ratio is 85% or more, it was evaluated as extremely good and represented by "A"; when the remaining film ratio is 80% or more and less than 85%, it was evaluated as very good and represented by "B"; when the remaining film ratio is 75% or more and less than 80%, it was evaluated as good and represented by "C"; when the remaining film ratio is less than 75%, it was evaluated as poor and represented by "D".

[0127] Remaining film ratio (%) = {(Average film thickness after development) / (Average film thickness before development)} × 100 ··· (Formula 1)

[0128] <Chemical resistance> After applying a negative-type radiation-sensitive resin composition on a silicon substrate by spin coating, a coating film with a film thickness of 2.5 μm was formed by pre-baking on a hot plate at 85 °C for 2 minutes. For the obtained coating film, a high-pressure mercury lamp (exposure amount at 365 nm is 100 mJ / cm 2 ) was used for overall exposure, and then development was carried out by the puddle method in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 25 °C for 60 seconds. Then, after rinsing with ultrapure water for 60 seconds under running water, a film was formed on the silicon substrate by drying. Next, a high-pressure mercury lamp (exposure amount at 365 nm is 200 mJ / cm 2After performing full exposure using [ [ ], post-baking was carried out in an oven at 85°C for 1 hour. The obtained substrate was immersed in an aqueous solution of 2-aminoethanol at 70% by mass at 60°C for 5 minutes. The average film thickness before and after immersion was measured, and the ratio of the average film thickness after immersion to the average film thickness before immersion (film thickness ratio before and after immersion) was calculated. This ratio was evaluated according to the following criteria. That is, when the film thickness ratio before and after immersion is 97% or more and less than 103%, it is evaluated as extremely good and represented by "A". When the film thickness ratio before and after immersion is 95% or more and less than 97%, it is evaluated as very good and represented by "B". When the film thickness ratio before and after immersion is 103% or more and less than 105%, it is evaluated as good and represented by "C". When the film thickness ratio before and after immersion is less than 95% or 105% or more, it is evaluated as defective due to peeling of the cured film or the like and represented by "D".

[0129] <Oxygen ashing resistance> A negative-type radiation-sensitive resin composition was spin-coated on a silicon substrate, and then pre-baked on a hot plate at 85°C for 2 minutes to form a coating film with a film thickness of 2.5 μm. For the obtained coating film, a high-pressure mercury lamp (exposure amount at 365 nm is 100 mJ / cm 2 ) was used to perform full exposure. After that, development was carried out by the liquid puddle method at 25°C for 60 seconds with an aqueous solution of 2.38% by mass of tetramethylammonium hydroxide. Then, after rinsing with ultrapure water for 60 seconds under running water, a film was formed on the silicon substrate by drying. Next, a high-pressure mercury lamp (exposure amount at 365 nm is 100 mJ / cm 2After performing overall exposure using [the relevant tool or method], post-baking was carried out in an oven at 85°C for 1 hour. The film (cured film) thus formed on the substrate was ashed under predetermined conditions (300 W, 30 sec, O₂ 30 sccm). The average film thickness before and after ashing was measured, and the residual film ratio (residual film ratio before and after ashing) was calculated based on the following formula (2). The oxygen ashing resistance was evaluated using the calculated residual film ratio according to the following criteria. That is, when the residual film ratio is 95% or more, it is evaluated as extremely good and represented by "A"; when the residual film ratio is 93% or more and less than 95%, it is evaluated as very good and represented by "B"; when the residual film ratio is 90% or more and less than 93%, it is evaluated as good and represented by "C"; when the residual film ratio is less than 90%, it is evaluated as poor and represented by "D".

[0130] Residual film ratio (%) = {(Average film thickness after ashing) / (Average film thickness before ashing)} × 100 ··· (Formula 2)

[0131] <Storage stability> 10 mL of the negative-type radiation-sensitive resin composition was placed in a screw tube and stored at 40°C in the dark for 3 days. Then, the viscosities before and after storage were measured in the same manner as the above-described viscosity measurement, and the viscosity increase rate before and after storage was confirmed based on the following formula (3). When the viscosity increase rate is less than 110%, it is evaluated as good and represented by "A"; when the viscosity increase rate is 110% or more, it is evaluated as poor and represented by "B".

[0132] Viscosity increase rate (%) = {(Viscosity after storage) / (Viscosity before storage)} × 100% ··· (Formula 3)

[0133]

Table 1

[0134] According to the negative-type radiation-sensitive resin compositions of Examples 1 to 11, it was shown that an insulating film having lithography performance, sufficient hardness even by heating at a relatively low temperature, and not easily cracked such as cracking can be formed. Further, when an insulating film was formed by the negative-type radiation-sensitive resin compositions of Examples 1 to 11, it was confirmed that less outgas was generated, and defects caused by outgas could be reduced.

Industrial Applicability

[0135] The negative-type radiation-sensitive resin composition can be suitably used as a material for forming an insulating film used in an organic EL device.

Explanation of Symbols

[0136] 10 Organic EL device 20 Organic EL display substrate 21 Support substrate 22 Anode layer 23 Organic light-emitting layer 24 Cathode layer 25 Adhesive layer 26 Encapsulation substrate 30 Touch panel 31 First sensor electrode 32 Second sensor electrode 33 Insulating film 34 Transparent substrate

Claims

1. (A) A polysiloxane having at least one thiol group, (B) A polyfunctional methacrylate (excluding polyfunctional acrylates), and (C) A photopolymerization initiator are contained, using an E-type viscometer equipped with a cone rotor (1°34’×R24), the viscosity measured under the conditions of 25°C and 50 rpm is 2.5 mPa·s or more and 5.0 mPa·s or less, A negative-type radiation-sensitive resin composition for forming an insulating film for an organic EL element.

2. The above (B) polyfunctional methacrylate is a tetrafunctional or higher methacrylate, The mass ratio of the above (B) polyfunctional methacrylate to the above (A) polysiloxane having at least one thiol group is 1 / 2 or more and 2 / 1 or less. The negative-type radiation-sensitive resin composition according to Claim 1.

3. The negative-type radiation-sensitive resin composition according to Claim 1 or Claim 2, wherein the above (C) photopolymerization initiator is a compound containing a structure represented by the following formula (1). 【Chemical 1】 [In the above formula (1), * indicates the bonding site with other parts in the above compound. ]

4. (D) Further contains an ultraviolet absorber, The content ratio of the above (D) ultraviolet absorber is 0.1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the above (A) polysiloxane having at least one thiol group. The negative-type radiation-sensitive resin composition according to any one of Claims 1 to 3.

5. (E) Further contains a base generator, The content ratio of the above (E) base generator is 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the above (A) polysiloxane having at least one thiol group. The negative-type radiation-sensitive resin composition according to any one of Claims 1 to 4.

6. A step of forming a coating film by applying the negative-type radiation-sensitive resin composition according to any one of Claims 1 to 5 directly or indirectly on a substrate, After the step of forming the above coating film, a step of irradiating at least a part of the above coating film with radiation, After the step of irradiating the above radiation, a step of developing the above coating film, and After the step of developing, a step of heating the above coating film at a temperature of 60°C or more and 120°C or less A method for forming an insulating film for an organic EL element comprising the steps of.

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