JP2020187246A - A method for manufacturing an electronic device using a radiation-sensitive resin composition, an electronic device provided with a radiation-sensitive resin composition, an insulating film and an insulating film. - Google Patents

Abstract

To provide an electronic apparatus that has excellent connection and improved reliability by forming a through hole in an insulation film including a radiation-sensitive resin composition, by a simple process.SOLUTION: A method for producing an electronic apparatus includes forming a coating film on a substrate using a radiation-sensitive resin composition, exposing the coating film via a multi-gradation mask, developing the exposed coating film, drying the developed coating film at 20°C-120°C, and forming an insulation layer including a through hole.SELECTED DRAWING: Figure 3

Description

One embodiment of the present invention relates to a method for manufacturing an electronic device using a radiation-sensitive resin composition, a radiation-sensitive resin composition, an insulating film, and an electronic device including an insulating film.

In recent years, flexible displays such as electronic paper have attracted attention, and as a substrate for a flexible display, a flexible substrate made of plastic using polyethylene terephthalate or the like has been studied. Since this flexible substrate expands or contracts when heated, lowering the temperature of the manufacturing process is being studied. Among them, lowering the firing temperature in the curing process of the interlayer insulating film, which is the highest temperature in the manufacturing process, is required. Has been done.

Examples of the insulating film material capable of lowering the temperature include a photocurable resin material. In the photocurable resin material, exposure and development are performed to open a contact hole (through hole) connecting the wiring of the upper layer and the lower layer of the insulating film. For example, when a negative photocurable resin material is exposed, its solubility in a developing solution is reduced, and an exposed portion remains after development. That is, in order to open the through hole, exposure is performed using a mask that blocks the pattern of the through hole. The exposed portion remaining after development can be cured at a low temperature to form an insulating film. For example, as a negative type photocurable resin composition, a radiation-sensitive resin composition containing an ethylene-based unsaturated group is disclosed (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-126068

However, such a photocurable resin material requires a large amount of exposure for curing. As a result, when the photo mask is used for exposure, the light leaking from the outer edge of the light-shielding region and the reflected light from the lower layer wiring may slightly expose the photocurable resin material in the light-shielding region, or the exposed region may be exposed. The photocurable resin material may be exposed unevenly. As a result, the flatness around the through hole may be deteriorated after development, or a residue / residual film may be generated inside the through hole, which may cause connection unnecessary. In order to improve the above problem, for example, it is conceivable to increase the addition of the light absorbing material or reduce the exposure amount. However, increasing the addition of the light absorbing material or suppressing the exposure amount results in insufficient exposure and photocuring in areas other than the light-shielding region, and the insulating film is damaged by etching and resist peeling in other processes. It becomes a problem that it receives or peels off.

In one embodiment of the present invention, in view of the above circumstances, a flat upper surface and a through hole without residue or residual film are formed in an insulating film using a photocurable resin material by a simple process, and good connection is achieved. An object of the present invention is to provide an electronic device with improved reliability.

In the method for manufacturing an electronic device according to an embodiment of the present invention, a coating film is formed on a substrate using a radiation-sensitive resin composition, the coating film is exposed through a multi-gradation mask, and the exposed coating film is applied. It includes developing a film and drying the developed coating film in the range of 20 ° C. to 120 ° C. to form an insulating layer having through holes.

One embodiment of the present invention provides an electronic device in which a flat upper surface and through holes are formed in an insulating film using a photocurable resin material by a simple process to improve good connection and reliability. Can be done.

It is a figure explaining the manufacturing method of the electronic apparatus which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the electronic apparatus which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the electronic apparatus which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the electronic apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of the electronic apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of the display device which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the display device which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the display device which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the display device which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the display device which concerns on one Embodiment of this invention. It is a figure explaining the manufacturing method of the display device which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to drawings and the like. However, the present invention includes many different aspects and is not construed as being limited to the embodiments exemplified below. In order to clarify the description, the drawings attached to the present specification may schematically represent the width, thickness, shape, etc. of each part as compared with the actual embodiment, but this is only an example. , The content of the present invention is not necessarily limited. Further, in the present invention, when a specific element described in a certain drawing and a specific element described in another drawing have the same or corresponding relationship, the same code (or a number described as the code) is used. , A, b, etc. are added after the above, and the repeated description may be omitted as appropriate. Furthermore, the letters "1st" and "2nd" for each element are convenient signs used to distinguish each element, and have no further meaning unless otherwise specified. ..

In the present specification, when a member or region is "above (or below)" another member or region, it is directly above (or directly below) the other member or region, unless otherwise specified. Not only when it is, but also when it is above (or below) another member or area, that is, when another component is included above (or below) another member or area. Also includes.

In the present specification, the expression "a structure is exposed from another structure" means an aspect in which a part of one structure is not covered by another structure, and is by another structure. The uncovered portion also includes an embodiment covered by yet another structure.

[Manufacturing method of electronic device 10]
A method of manufacturing the electronic device 10 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 4 with reference to a cross-sectional view. FIG. 1 is a cross-sectional view showing a step of forming a base layer in the method for manufacturing an electronic device according to an embodiment of the present invention. As shown in FIG. 1, a base layer 105 is formed on substantially the entire surface of the substrate 123.

FIG. 2 is a cross-sectional view showing a step of forming a first conductive layer in the method for manufacturing an electronic device according to an embodiment of the present invention. First, a conductive layer is formed on substantially the entire surface of the substrate 123, a resist mask is formed by a photolithography step, and a pattern of the first conductive layer 110 is formed by etching.

FIG. 3 is a cross-sectional view showing a step of forming an insulating layer in the method for manufacturing an electronic device according to an embodiment of the present invention. As shown in FIG. 3, first, an insulating layer is formed on substantially the entire surface of the substrate 123 so as to cover the first conductive layer 110. Here, the insulating layer is formed by applying a photocurable resin material. The through hole 135 of the insulating layer 130 is formed by a photolithography process. In the present embodiment, one through hole 135 is formed by multi-gradation exposure.

In the present embodiment, the multi-gradation mask 200 is used for exposing the insulating layer. The multi-gradation mask 200 refers to a mask in which the light transmittance required for controlling an appropriate exposure amount is adjusted. The multi-gradation mask 200 includes, as a multi-gradation mask pattern, a gray tone mask in which a slit equal to or lower than the resolution of the exposure machine is provided and the slit portion blocks a part of light to realize an intermediate exposure, and a semi-transmissive film. Halftone masks that realize intermediate exposure by using them are known, but in the present embodiment, both multi-tone masks 200 can be used. By exposing through the light transmission region 201, the semitransmission region 202, and the non-transmission region 203 of the multi-gradation mask 200, three types of portions, an exposed portion, an intermediate exposed portion, and an unexposed portion, are formed on the insulating layer. To. In the present embodiment, the light transmittance N of the semitransparent region 202 of the multi-gradation mask 200 is preferably 10% or more and 80% or less, and more preferably 20% or more and 60% or less. In the present specification, the term “transmittance” refers to the value of “the amount of light emitted through the semi-transmissive region when the total amount of light emitted from the light source is 100%”, and the transmittance of the film is particularly limited. Unless otherwise specified, it refers to the value at room temperature (25 ° C.) and irradiation at a ghii line of 5 to 1000 mJ / cm ² .

As the irradiation light used for exposure, radiation having a wavelength in the range of 190 nm to 450 nm is preferable, and radiation containing ultraviolet rays having a wavelength of 300 nm is more preferable. The exposure amount is preferably ^{500J / m 2 ~6,000J / m 2} , 1,000J / m 2 ~3,000J / m 2 is more preferable. This exposure amount is a value obtained by measuring the intensity of radiation at a wavelength of 300 nm with an illuminometer (“OAI model 356” manufactured by OAI Optical Associates).

The non-transmissive region 203 of the multi-gradation mask 200 corresponds to the through hole 135 of the insulating layer 130. The semitransparent region 202 of the multi-gradation mask 200 corresponds to an inclined portion on the inner side surface connecting the upper end portion of the opening and the lower end portion of the opening of the through hole 135 of the insulating layer 130. The translucent region 202 is arranged so as to surround the non-transparent region 203. That is, the diameter D1 of the non-transmissive region 203 of the multi-gradation mask 200 corresponds to the diameter at the lower end of the opening of the through hole 135, and the outer diameter D2 of the semi-transmissive region 202 of the multi-gradation mask 200 corresponds to the upper end of the opening of the through hole 135. Corresponds to the diameter of the part. The minimum width d of the inclined portion on the inner surface of the through hole 135 can be appropriately selected depending on the depth of the through hole 135. In other words, the minimum width d of the semitransparent region 202 can be appropriately selected depending on the film thickness L of the insulating layer 130. The minimum width d of the semitransparent region 202 is preferably in the range of 0.01 × L or more and 0.10 × L or less. The minimum width d of the semi-transmissive region 202 can be appropriately selected depending on the light transmittance N of the semi-transmissive region 202. The minimum width d of the semitransparent region 202 is preferably in the range of 10 × N / 100 or more and 80 × N / 100 or less.

In this way, by multi-gradation exposure of one through hole 135 (pattern) with at least two exposure amounts using the multi-gradation mask 200, a tapered shape having an inclined portion on the inner side surface can be formed. .. Further, even if the exposure amount in the light transmitting region 201 is increased, by arranging the semi-transmissive region 202 between the light transmitting region 201 and the non-transmitting region 203, the light leaking from the light transmitting region 201 and the first conductive layer It is possible to prevent the photocurable resin material in the non-transmissive region 203 from being exposed by the reflected light from the 110 (lower layer wiring). As a result, after the photocurable resin material is developed, the flatness around the through hole 135 deteriorates, or a residue / residual film is generated inside the through hole 135, so that the first conductive layer 110 and the second conductive layer 120 It is possible to suppress the need for connection.

Then, by developing the insulating layer, as shown in FIG. 4, a pattern of the insulating layer 130 having a through hole 135 having an inclined portion on the inner side surface is formed. Since the insulating layer is a negative type radiation-sensitive resin composition, the exposed portion remains as a pattern of the insulating layer 130, the intermediate exposed portion remains relatively thin as an inclined portion, and the unexposed portion remains in the developer. It melts and becomes a through hole 135.

The developing solution is preferably an alkaline aqueous solution. Examples of the alkali include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate and ammonia; and quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. Be done. As the developing solution, an organic solvent such as a ketone-based organic solvent or an alcohol-based organic solvent can also be used. An appropriate amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant can be added to the alkaline aqueous solution for use. The concentration of alkali in the alkaline aqueous solution is preferably 0.1% by mass or more and 5% by mass or less from the viewpoint of obtaining suitable developability.

Examples of the developing method include a liquid filling method, a dipping method, a rocking dipping method, a shower method and the like. The developing time varies depending on the composition of the photocurable resin material, but is usually about 10 seconds to 180 seconds. A desired pattern can be formed by, for example, washing with running water for 30 seconds to 90 seconds following such a developing process, and then air-drying with compressed air or compressed nitrogen, for example.

The developed insulating layer can form the insulating layer 130 by drying and curing in a temperature range of 20 ° C. or higher and 150 ° C. or lower for 10 minutes or more and 100 minutes or less.

After that, by forming the second conductive layer 120, the electronic device 10 as shown in FIG. 5 is formed. The second conductive layer 120 is formed so as to cover the through hole 135. That is, the second conductive layer 120 is formed on the bottom surface of the through hole 135 (on the first conductive layer 110 where the through hole 135 is exposed) and the inner surface of the through hole 135. Further, the second conductive layer 120 is preferably formed on the upper surface of the insulating layer 130 (the side of the insulating layer 130 opposite to the first conductive layer 110). Therefore, it is preferable that the width D3 of the second conductive layer 120 is formed larger than the diameter D2 at the upper end of the opening of the through hole 135 in the top view. Here, the width indicates the minimum width, and the caliber indicates the minimum caliber. By forming the second conductive layer 120 in this way, the second conductive layer 120 can be reliably arranged on the bottom surface and the inner side surface of the through hole 135, and the connection between the second conductive layer 120 and the first conductive layer 110 can be ensured. The reliability can be improved.

It is preferable that the width D4 of the first conductive layer 110 and the width D3 of the second conductive layer 120 are formed substantially the same. By forming the first conductive layer 110 and the second conductive layer 120 in this way, it is possible to improve the density of the wiring, and the display unit can be effectively utilized.

According to the method for forming the insulating layer 130 according to the present embodiment, a flat upper surface and a tapered through hole can be formed in the insulating film using the photocurable resin material by a simple process. This makes it possible to provide an electronic device with good connection and improved reliability.

[Structure of electronic device 10]
An outline of the electronic device 10 according to the first embodiment of the present invention will be described with reference to FIG. The electronic device 10 of the first embodiment is a self-luminous display using a liquid crystal display device (Liquid Crystal Display Device: LCD) and a self-luminous element (Organic Light-Emitting Device: OLED) such as an organic EL element or a quantum dot on the display unit. It is used for each pixel of each display device, a selection transistor, and a drive transistor in a device or a reflection type display device such as electronic paper. However, the electronic device 10 according to the present invention is not limited to that used for a display device, and may be used, for example, for an integrated circuit (Integrated Circuit: IC) such as a microprocessor (Micro-Processing Unit: MPU). ..

FIG. 5 is a cross-sectional view showing an outline of an electronic device according to an embodiment of the present invention. As shown in FIG. 5, the electronic device 10 has a first conductive layer 110, a second conductive layer 120, and an insulating layer 130. The electronic device 10 is arranged above the base layer 105 arranged on the substrate 123.

The first conductive layer 110 is arranged above the substrate 123 via a base layer 105 having an arbitrary configuration. The second conductive layer 120 is arranged above the first conductive layer 110. The insulating layer 130 is arranged between the first conductive layer 110 and the second conductive layer 120. The insulating layer 130 has a through hole 135 that exposes the first conductive layer 110. The second conductive layer 120 is electrically connected to the first conductive layer 110 through the through hole 135 of the insulating layer 130. The second conductive layer 120 is arranged so as to be in contact with the inner side surface of the through hole 135, and is connected to the first conductive layer 110 where the through hole 135 is exposed at the bottom of the through hole 135.

In the present embodiment, the through hole 135 has a tapered structure. Therefore, the through hole 135 has an inclined portion on the inner side surface, and the diameter D1 at the lower end of the opening of the through hole 135 is smaller than the diameter D2 at the upper end of the opening of the through hole 135. The angle θ formed by the inner surface of the through hole 135 and the lower surface of the insulating layer 130 is an acute angle. The angle θ formed by the inner surface of the through hole 135 and the lower surface of the insulating layer 130 is preferably in the range of 40 ° or more and 85 ° or less. When the angle θ formed by the inner surface of the through hole 135 and the lower surface of the insulating layer 130 is less than 40 °, it becomes difficult to form a fine wiring pattern in the electronic device 10. When the angle θ formed by the inner surface of the through hole 135 and the lower surface of the insulating layer 130 is larger than 85 °, it becomes difficult to form the second conductive layer 120 on the inner surface of the through hole 135, and the second conductive layer 120 is formed on the insulating layer. It causes poor continuity of the electrode due to peeling or cracking of the formed transparent electrode.

In the present embodiment, the second conductive layer 120 is arranged on the bottom surface of the through hole 135 (on the first conductive layer 110 where the through hole 135 is exposed) and the inner surface of the through hole 135. Further, the second conductive layer 120 is preferably arranged on the upper surface of the insulating layer 130 (the side of the insulating layer 130 opposite to the first conductive layer 110). Therefore, it is preferable that the width D3 of the second conductive layer 120 is larger than the diameter D2 at the upper end of the opening of the through hole 135 in the top view. When the second conductive layer 120 is configured in this way, the connection reliability between the second conductive layer 120 and the first conductive layer 110 can be improved.

In the present embodiment, it is preferable that the width D4 of the first conductive layer 110 and the width D3 of the second conductive layer 120 are substantially the same. By configuring the first conductive layer 110 and the second conductive layer 120 in this way, it is possible to improve the density of the wiring, and the display unit can be effectively utilized.

[Material of each member constituting the electronic device 10]
As the substrate 123, for example, a polyethylene terephthalate substrate is used. As the substrate 123, in addition to the polyethylene terephthalate substrate, for example, polyester resin such as polyethylene naphthalate (PEN), polyacrylic nitrile resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyether sulfone (PES). Examples thereof include resins, polyamide resins, cycloolefin resins, polystyrene resins, polyamideimide resins, and polyvinyl chloride resins. In particular, it is preferable to use a material having a low coefficient of thermal expansion, and for example, a polyamide-imide resin, a polyimide resin, PET and the like can be preferably used. Further, a substrate in which a fiber body is impregnated with a resin (also referred to as a prepreg) or a substrate in which an inorganic filler is mixed with an organic resin to reduce the coefficient of thermal expansion can be used.

On the other hand, when the substrate 123 does not need to have flexibility, a translucent insulating substrate such as a glass substrate, a quartz substrate, and a sapphire substrate may be used as the substrate 123. When the electronic device 10 is an integrated circuit that is not a display device, a substrate that does not have translucency, such as a silicon substrate, a silicon carbide substrate, a semiconductor substrate such as a compound semiconductor substrate, or a conductive substrate such as a stainless steel substrate, is used. It may be used.

As the base layer 105, a material that improves the adhesion between the substrate 123 and the first conductive layer 110 is used. For example, as the base layer 105, silicon oxide (SiO _x ), silicon nitride (SiO _x N _y ), silicon nitride (SiN _{x Oy} ), silicon nitride (SiN _x ), aluminum oxide (AlO _x ), and aluminum nitride Aluminum (AlO _x N _y ), aluminum nitride oxide (AlN _x O _y ), aluminum nitride (AlN _x ) and the like are used (x and y are arbitrary positive values). A structure in which these films are laminated may be used. Here, the base layer 105 may be omitted if sufficient adhesion between the substrate 123 and the first conductive layer 110 is ensured. As the base layer 105, a TEOS layer or an organic insulating material may be used in addition to the above-mentioned inorganic insulating material.

As the first conductive layer 110 and the second conductive layer 120, a general metal material or a conductive semiconductor material is used. For example, as the first conductive layer 110 and the second conductive layer 120, aluminum (Al), titanium (Ti), chromium (Cr), cobalt (Co), nickel (Ni), zinc (Zn), molybdenum (Mo), Indium (In), tin (Sn), hafnium (Hf), titanium (Ta), tungsten (W), platinum (Pt), bismuth (Bi) and the like are used. As the first conductive layer 110 and the second conductive layer 120, alloys of the above materials may be used, or nitrides of the above materials may be used. As the first conductive layer 110 and the second conductive layer 120, ITO (indium tin oxide), IGO (indium tin oxide), IZO (indium zinc oxide), GZO (zinc oxide to which gallium is added as a dopant), etc. The conductive oxide semiconductor of the above may be used. The first conductive layer 110 and the second conductive layer 120 may be a single layer or may be a laminate of the above materials.

A radiation-sensitive resin composition is used as the insulating layer 130. As the radiation-sensitive resin composition, for example, a negative type radiation-sensitive resin composition is preferable. The radiation-sensitive resin composition may contain a polymer, a polymerizable compound, a radiation-sensitive polymerization initiator, an additive, and a solvent.

The radiation-sensitive resin composition preferably contains an alkali-soluble resin. As the alkali-soluble resin, a resin having an acidic functional group such as a carboxy group or a phenolic hydroxyl group is preferable, and a carboxy group-containing polymer is more preferable. Examples of the alkali-soluble resin include an acid-modified epoxy (meth) acrylate resin, a novolak resin, a polyamic acid which is a polyimide precursor and its partial imidized product, a polyhydroxyamide which is a polybenzoxazole precursor, and a phenol-xylylene glycol condensation. A single or copolymer of a monomer having a phenolic hydroxyl group such as a resin, a cresol-xylylene glycol condensed resin, a phenol-dicyclopentadiene condensed resin, hydroxystyrene and isopropenylphenol, or an ethylene having one or more carboxy groups. Examples thereof include a copolymer of a sex-unsaturated monomer and another copolymerizable ethylenically unsaturated monomer.

The alkali-soluble resin can have an ethylenically unsaturated group. As the alkali-soluble resin, an acid-modified epoxy (meth) acrylate resin, which is a resin having a carboxy group and an ethylenically unsaturated group, is preferable from the viewpoint that both alkali solubility and cured film physical properties can be compatible at a high level. Acid-modified cresol novolac type epoxy (meth) acrylate resin, phenol novolac type epoxy (meth) acrylate resin, bisphenol A type epoxy (meth) acrylate resin, bisphenol F type epoxy (meth) acrylate resin, biphenyl type epoxy (meth) ) Acrylic resin, trisphenol methane type epoxy (meth) acrylate resin can be mentioned.

Examples of the acid-modified cresol novolac type epoxy (meth) acrylate resin include polymers represented by the following formula (1). The acid-modified cresol novolac type epoxy (meth) acrylate resin is, for example, anhydrous for alkali solubility in an epoxy (meth) acrylate resin obtained by reacting a cresol novolac type epoxy resin with (meth) acrylic acid. It is obtained by reacting an acid anhydride such as phthalic acid, 1,2,3,6-tetrahydrophthalic anhydride.

The acid-modified cresol novolac type epoxy (meth) acrylate resin has a rigid main chain skeleton of the cresol novolac type epoxy resin, an ethylenically unsaturated group, and a carboxy group, so that it can be cured and baked at a low temperature. Regardless, it is possible to form a cured film having excellent solvent resistance and heat resistance.

The polymer having an ethylenically unsaturated group and a carboxyl group may contain a structural site represented by the following formula (1).
(In formula (1), R ¹ represents a hydrogen atom and a methyl group, R ² represents a divalent hydrocarbon group. * Indicates a bond position.)

A polymer having an ethylenically unsaturated group and a carboxyl group may be represented by the following formula (2).
Here, in equation (1), n and m independently represent integers of 1 to 30.

By containing the bisphenol epoxy resin and the group containing an ethylenically unsaturated group, the polymer represented by the above chemical formula 1 can be sufficiently curable even at low temperature curing. Here, curing at a low temperature means that curing is possible at a temperature in the range of, for example, 20 ° C. or higher and 120 ° C. or lower.

The acid value of the alkali-soluble resin is, for example, 10 to 200 mgKOH / g, preferably 30 to 270 mgKOH / g, and more preferably 50 to 250 mgKOH / g. The acid value represents the number of mg of KOH required to neutralize 1 g of the solid content of the alkali-soluble resin.

The alkali-soluble resin has a weight average molecular weight (Mw) of usually 1,000 to 100,000, preferably 3,000 to 50,000. Mw refers to the polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (eluting solvent: tetrahydrofuran).

The content of the alkali-soluble resin in the radiation-sensitive resin composition is usually 30% by mass or more, preferably 40% by mass or more, based on 100% by mass of the solid content of the composition, and is the upper limit of the content of the alkali-soluble resin. The value is usually 90% by mass based on 100% by mass of the solid content of the composition, and in one embodiment, 70% by mass or 60% by mass. In such an aspect, in addition to further improvement of brightness, alkali developability, storage stability of the composition, pattern shape, and chromaticity characteristics can be improved. The solid content is all components except the solvent.

<Polymerizable compound>
The polymerizable compound is a polymerizable compound other than the above-mentioned alkali-soluble resin having an ethylenically unsaturated group, and the polymerizable compound is preferably a compound having two or more polymerizable groups. Examples of the polymerizable group include an ethylenically unsaturated group, an oxylanyl group (epoxide group), an oxetanyl group, and an N-alkoxymethylamino group. As the polymerizable compound, a compound having two or more (meth) acryloyl groups or a compound having two or more N-alkoxymethylamino groups is preferable.

Examples of the compound having two or more (meth) acryloyl groups include a reaction product of an aliphatic polyhydroxy compound and (meth) acrylic acid [polyfunctional (meth) acrylate], and a caprolactone-modified polyfunctional (meth). Acrylate, alkylene oxide-modified polyfunctional (meth) acrylate, reaction product of (meth) acrylate having a hydroxyl group and polyfunctional isocyanate [polyfunctional urethane (meth) acrylate], (meth) acrylate having a hydroxyl group and acid anhydride Examples of the reaction product with and [polyfunctional (meth) acrylate having a carboxy group]. Specific examples of the aliphatic polyhydroxy compound, the (meth) acrylate having a hydroxyl group, the polyfunctional isocyanate and the acid anhydride include the compounds described in paragraph [0065] of JP-A-2015-232964, which are modified with caprolactone. Examples of the polyfunctional (meth) acrylate and the alkylene oxide-modified polyfunctional (meth) acrylate include the compounds described in paragraph [0066] of the same publication.

Specific examples include, for example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and succinic acid-modified pentaerythritol tri (meth) acrylate. ) Acrylate can be mentioned.

Examples of the compound having two or more N-alkoxymethylamino groups include compounds having a melamine structure, a benzoguanamine structure, and a urea structure, and specific examples thereof include paragraphs of JP2015-232964A. 0067] can be mentioned.

When the radiation-sensitive resin composition contains a polymerizable compound, the content of the polymerizable compound is usually 30 to 200 parts by mass, preferably 30 to 100 parts by mass, based on 100 parts by mass of the alkali-soluble resin. It is preferably 45 to 100 parts by mass. With such an embodiment, curability and developability can be further enhanced, and brightness can be further improved.

<Radiation-sensitive polymerization initiator>
The radiation-sensitive polymerization initiator cures an alkali-soluble resin having an ethylenically unsaturated group and a polymerizable compound by exposure to radiation such as visible light, ultraviolet rays, electron beams, and X-rays, preferably visible light and / or ultraviolet rays. A compound that produces an active species that can initiate a reaction. Examples of the radiation-sensitive polymerization initiator include thioxanthone-based compounds, acetophenone-based compounds, biimidazole-based compounds, triazine-based compounds, O-acyloxime-based compounds, onium salt-based compounds, benzoin-based compounds, benzophenone-based compounds, and α-. Examples thereof include diketone compounds, polynuclear quinone compounds, diazo compounds, and imide sulfonate compounds. Specific examples of these include the compounds described in paragraphs [0073] to [0078] of Japanese Patent Application Laid-Open No. 2015-232964.

When the radiation-sensitive resin composition contains a polymerizable compound, the content of the radiation-sensitive polymerization initiator is usually 0.01 to 120 parts by mass, preferably 1 to 1 part by mass with respect to 100 parts by mass of the polymerizable compound. It is 100 parts by mass. In one embodiment, the content of the radiation-sensitive polymerization initiator is 11 parts by mass or more or 13 parts by mass or more with respect to 100 parts by mass of the polymerizable compound. With such an aspect, the curability and the coating property can be further enhanced, and the brightness can be further improved.

In one embodiment, the content of the radiation-sensitive polymerization initiator in the radiation-sensitive resin composition is usually 1 to 20 parts by mass, preferably 1 to 20 parts by mass, based on 100 parts by mass of the alkali-soluble resin having an ethylenically unsaturated group. It is 5 to 15 parts by mass.

<Additive>
The radiation-sensitive resin composition can also contain various additives, if necessary. Additives include, for example, sensitizers, dispersants, fillers, polymer compounds, surfactants, adhesion promoters, antioxidants, UV absorbers, anti-aggregation agents, residue improvers, and developability improvers. Can be mentioned.
In particular, as the adhesion accelerator, the coupling agent described in International Publication No. 2017/094831 can be used. As the ultraviolet absorber, the ultraviolet absorber described in JP-A-2004-190006 or the like can be used. As the antioxidant, the antioxidant described in International Publication No. 2011/0462330 can be used.

<Preparation of radiation-sensitive resin composition>
The radiation-sensitive resin composition can be prepared by an appropriate method. For example, it can be prepared by mixing each component such as an alkali-soluble resin, a polymerizable compound, and a radiation-sensitive polymerization initiator with a solvent and an additive added arbitrarily.

Examples of the solvent include (poly) alkylene glycol monoalkyl ethers, lactic acid alkyl esters, (cyclo) alkyl alcohols, keto alcohols, (poly) alkylene glycol monoalkyl ether acetates, other ethers, and ketones. , Diacetates, alkoxycarboxylic acid esters, other esters, aromatic hydrocarbons, amides or lactams, and specific examples thereof include paragraphs [2002] of JP-A-2015-232964. Examples thereof include the solvents described in [0085].

The content of the solvent is not particularly limited, but the solid content concentration in the radiation-sensitive resin composition is preferably 5 to 50% by mass, more preferably 10 to 40% by mass.

The photopolymerization initiator may include a radiation-sensitive polymerization initiator. The photopolymerization initiator may contain at least one selected from an oxime compound, a triazine compound, a benzoin compound, an acetophenone compound, a xanthone compound and an imidazole compound. As the radiation-sensitive polymerization initiator, for example, a photoacid generator, a photobase generator, or the like can be used.

[Structure of display device 100]
FIG. 6 is a cross-sectional view showing the structure of a pixel portion in the display device 100 including the electronic device 10 shown in FIG. FIG. 6 is a schematic cross-sectional view in which one pixel included in the display device 100 is enlarged.

As shown in FIG. 6, the display device 100 includes a substrate 123, a TFT array 30, and an alignment film 80. The display device 100 may further include a liquid crystal layer, an alignment film, a color filter layer, a translucent conductive layer, a polarizing plate, and the like.

The TFT array 30 includes a base layer 31, a thin film transistor 190, a capacitive element 196, an interlayer film 37, and a pixel electrode 70. The electronic device 10 according to the present embodiment may be applied to, for example, a connection structure between the thin film transistor 190 and the pixel electrode 70 via the interlayer film 37.

The base layer 31 prevents the diffusion of impurities from the substrate 123, and the base layer 31 can be provided as needed. As the base layer 31, an insulating material such as silicon oxide or silicon nitride can be used. Further, a structure in which silicon oxide and silicon nitride are laminated can be provided as the base layer 31.

The thin film transistor 190 includes a semiconductor layer 32, a gate insulating layer 33, a gate electrode 34, an interlayer film 35, a source electrode 36, and a drain electrode 38. Each of the source electrode 36 and the drain electrode 38 is electrically connected to the semiconductor layer 32 via the first openings 39a and 39b. As the material of the semiconductor layer 32, for example, an oxide semiconductor such as silicon or IGZO can be used. As the material of the gate electrode 34, the source electrode 36, and the drain electrode 38, a conductive metal material such as copper, aluminum, titanium, or molybdenum can be used. Further, as the material of the gate insulating layer 33 and the interlayer film 35, an insulating material such as silicon oxide or silicon nitride can be used. The capacitive element 196 can use the capacitive potential line 193 and the drain electrode 38 as electrodes and the interlayer film 35 as a dielectric, but is not limited thereto.

The TFT array 30 has a pixel electrode 70 that is electrically connected to the thin film transistor 190. The pixel electrode 70 is provided on the interlayer film 37 formed on the upper layer of the thin film transistor 190. The pixel electrode 70 is electrically connected to the thin film transistor 190 via a second opening (contact hole) 194 formed in the interlayer film 37. A plurality of pixels included in the display device 100 have the same configuration.

The pixel electrode 70 is electrically connected to the drain electrode 38 of the thin film transistor 190 via the second opening 194. In this case, the drain electrode 38 may correspond to the first conductive layer 110 of the electronic device 10, the pixel electrode 70 may correspond to the second conductive layer 120 of the electronic device 10, and the interlayer film 37 may correspond to the insulating layer 130 of the electronic device 10. That is, the interlayer film 37 may be formed in the same manner as the insulating layer 130 of the electronic device 10.

In the display device 100 according to the present embodiment, the interlayer film 37 provided between the pixel electrode 70 and the thin film transistor 190 is formed by using a radiation-sensitive resin composition, and the second opening 194 is formed by multi-gradation exposure. As a result, the process temperature can be lowered, and the display device 100 with good connection between the pixel electrode 70 and the thin film transistor 190 and improved reliability can be provided.

[Manufacturing method of display device 100]
A method of manufacturing the display device 100 according to the embodiment of the present invention will be described with reference to FIGS. 7 to 11 with reference to a cross-sectional view. FIG. 7 is a cross-sectional view showing a process in which a base layer 31, a thin film transistor 190, and a capacitance element 196 are formed on a substrate 123 in a method for manufacturing a display device according to an embodiment of the present invention.

As shown in FIG. 7, a base layer 31 is formed on substantially the entire surface of the substrate 123. A semiconductor layer 32 is formed in a region corresponding to each pixel. The semiconductor layer 32 is formed by using a semiconductor material such as amorphous silicon or low-temperature polysilicon. After that, the gate insulating layer 33 is formed on substantially the entire surface of the substrate 123. The gate insulating layer 33 is formed by using an insulating material such as silicon oxide or silicon nitride. The gate electrode 34 and the capacitive potential line 193 are formed using, for example, a conductive metal material such as copper, aluminum, titanium, or molybdenum. The interlayer film 35 can form the gate insulating layer 33 using the same material. The source electrode 36 and the drain electrode 38 are each formed on the interlayer film 35. The source electrode 36 and the drain electrode 38 can be formed by using the same materials as the gate electrode 34 and the capacitance potential line 193.

FIG. 8 is a cross-sectional view showing a step of forming an interlayer film 37 in the method for manufacturing a display device according to an embodiment of the present invention. As shown in FIG. 8, first, an interlayer film 37 is formed so as to cover the source electrode 36 and the drain electrode 38 on substantially the entire surface of the substrate 123. Here, the interlayer film 37 is formed by applying a radiation-sensitive resin composition. The second opening 194 of the interlayer film 37 is formed by a photolithography step. In the present embodiment, one second opening 194 is formed by multi-gradation exposure.

9 and 10 are cross-sectional views showing a step of forming a contact hole in the method of manufacturing a display device according to an embodiment of the present invention. As shown in FIG. 9, first, the insulating layer is exposed using the multi-gradation mask 200. By exposing through the light transmission region 201, the semitransmission region 202, and the non-transmission region 203 of the multi-gradation mask 200, three types of portions, an exposed portion, an intermediate exposed portion, and an unexposed portion, are formed on the insulating layer. To. The light transmission region 201 of the multi-gradation mask 200 corresponds to the lower end of the opening of the second opening 194 of the interlayer film 37. The semitransparent region 202 of the multi-gradation mask 200 corresponds to an inclined portion on the inner side surface connecting the upper end portion of the opening and the lower end portion of the opening of the second opening 194 of the interlayer film 37. That is, the semi-transmissive region 202 is arranged so as to surround the light transmissive region 201.

FIG. 10 is a cross-sectional view showing a step of developing an insulating layer in the method for manufacturing a display device according to an embodiment of the present invention. As shown in FIG. 10, by developing the insulating layer, a pattern of the interlayer film 37 having the second opening 194 having the inclined portion on the inner side surface is formed. Since the insulating layer is a negative type radiation-sensitive resin composition, the exposed portion remains as a pattern of the interlayer film 37, the intermediate exposed portion remains relatively thin as an inclined portion, and the unexposed portion remains in the developer. It melts to form the second opening 194. The developed insulating layer can form an interlayer film 37 by drying and curing in a temperature range of 20 ° C. or higher and 150 ° C. or lower for 10 minutes or more and 100 minutes or less.

In this way, it is possible to form a tapered shape having an inclined portion on the inner side surface by multi-gradation exposure of one second opening 194 (pattern) with at least two exposure amounts using the multi-gradation mask 200. .. Further, even if the exposure amount in the light transmitting region 201 is increased, by arranging the semi-transmissive region 202 between the light transmitting region 201 and the non-transmitting region 203, the light leaking from the light transmitting region 201 and the drain electrode 38 It is possible to prevent the radiation-sensitive resin composition in the non-transmissive region 203 from being exposed by the reflected light from (lower layer wiring). As a result, after the radiation-sensitive resin composition is developed, the flatness around the second opening 194 deteriorates, or a residue / residual film is generated inside the second opening 194, so that the drain electrode 38 and the pixel electrode 70 It is possible to suppress the need for connection. Further, the pixel electrode 70 can be formed flat, and for example, poor light distribution of the liquid crystal arranged on the upper surface can be suppressed.

FIG. 11 is a cross-sectional view showing a step of forming a pixel electrode 70 in the method of manufacturing a display device according to an embodiment of the present invention. As shown in FIG. 11, by forming the pixel electrode 70 on the interlayer film 37 including the second opening 194, the pixel electrode 70 electrically connected to the thin film transistor 190 can be formed. The display device 100 shown in FIG. 6 can be manufactured by forming the alignment film 80 so as to cover the interlayer film 37 and the pixel electrode 70.

In the method of manufacturing the display device 100 according to the present embodiment, the interlayer film 37 provided between the pixel electrode 70 and the thin film transistor 190 is formed by using a radiation-sensitive resin composition, and the second opening 194 is exposed to multiple gradations. By forming by, the process temperature can be lowered. By using such a manufacturing method, it is possible to provide a display device 100 having good connection between the pixel electrode 70 and the thin film transistor 190 and improved reliability.

Claims (15)

A coating film is formed on the substrate using the radiation-sensitive resin composition.
The coating film is exposed through a multi-tone mask and
The exposed coating film is developed and
Drying the developed coating film in the range of 20 ° C. to 120 ° C. to form an insulating layer having through holes.
A method of manufacturing an electronic device, including. The method for manufacturing an electronic device according to claim 1, wherein forming an insulating layer having the through hole forms an inclined portion in the through hole. The method for manufacturing an electronic device according to claim 2, wherein the multi-gradation mask has a non-transmissive region in which the through hole is arranged and a semi-transmissive region in which the inclined portion is arranged. The method for manufacturing an electronic device according to claim 3, wherein the semitransparent region is arranged so as to surround the non-transparent region. The electronic device according to claim 3 or 4, wherein the minimum width d of the semi-transmissive region is 10 × N / 100 or more and 80 × N / 100 or less when the light transmittance of the semi-transmissive region is N. Production method. The method for manufacturing an electronic device according to any one of claims 3 to 5, wherein the light transmittance in the semi-transmissive region is 10% or more and 80% or less. The method for manufacturing an electronic device according to any one of claims 3 to 6, wherein a second conductive layer is formed so as to cover the through hole after the through hole is formed. The method for manufacturing an electronic device according to claim 7, wherein the second conductive layer is formed larger than the through hole. Before forming the coating film, a first conductive layer is formed on the substrate, and the first conductive layer is formed.
The method for manufacturing an electronic device according to claim 7 or 8, wherein the second conductive layer is connected to the first conductive layer through the through hole. The production of the electronic device according to any one of claims 1 to 9, wherein the radiation-sensitive resin composition comprises a polymer having an ethylenically unsaturated group and a carboxyl group, and a radiation-sensitive polymerization initiator. Method. The method for producing an electronic device according to claim 10, wherein the polymer having an ethylenically unsaturated group and a carboxyl group contains a structural portion represented by the following formula (1).
(In formula (1), R ¹ represents a hydrogen atom and a methyl group, R ² represents a divalent hydrocarbon group. * Indicates a bond position.) The method for producing an electronic device according to claim 10 or 11, wherein the polymer having an ethylenically unsaturated group and a carboxyl group is shown in (2) below.
[In equation (2), n and m each independently represent an integer of 1 to 30. ] A negative type radiation-sensitive resin composition used in the method for manufacturing an electronic device according to any one of claims 1 to 12. An insulating film formed from the radiation-sensitive resin composition according to claim 13. A display device including the insulating film according to claim 14.