JP2008059945A - Method of manufacturing electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method capable of precisely carrying out gap and alignment adjustment of an electronic device sealing two sheets of substrates with a photocuring sealing material with the use of photocuring resin composition with sufficient working life, and also capable of sealing a large-area electronic device. <P>SOLUTION: The manufacturing method includes a process of carrying out point application on an application face in equal intervals of a sealing material containing (A) a monofunctional oxetane compound containing a hydroxyl group, (B) a polyfunctional oxetane compound or a polyfunctional epoxy compound, and (C) sulfonium salt light cation polymerization initiator of which a counter anion is antimonate or phosphate, a process (b) of irradiating ultraviolet rays, a process of bonding two sheets of substrates, and a process (d) of curing a composition between the substrates by ultraviolet irradiation and/or heating. A gap and/or alignment adjustment between the substrates is carried out at room temperature after the process (b) and before the process (d). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an electronic device. Specifically, the present invention relates to a method of manufacturing an electronic device having a structure in which two substrates are sealed with a photocurable sealing material with a narrow gap, and in particular, a support substrate and an opaque sealing substrate for forming an organic EL element are made of resin. The present invention relates to a method for producing a sealed top emission organic EL element.

  In the production of organic EL elements and other opaque substrates, photo-curing resin compositions are used because thermosetting sealing resins take a long time to cure and the mass production efficiency is poor. Has been. For example, in Patent Document 1, as a method of sealing a support substrate provided with an organic EL layer with a sealing substrate, an outer peripheral sealing layer made of a UV curable resin is formed on the substrate, and the sealing substrate and When alignment with the support substrate is completed, UV curable adhesive is applied to the outer periphery using a dispenser as a method of sealing by curing the UV curable resin by irradiating UV light, or as a method of manufacturing a color organic EL element. After coating, the organic EL element and the color conversion filter substrate are brought into close contact with each other, the light emitting portion of the organic EL element and the color conversion filter layer are aligned, and then the ultraviolet curable adhesive is irradiated with ultraviolet rays. A manufacturing method is disclosed in which the outer peripheral sealing layer is formed by curing the adhesive layer.

  According to this manufacturing method, an outer peripheral sealing layer is possible, but since the opaque portion of the substrate does not transmit light sufficiently, photocuring at the inner portion of the substrate where ultraviolet rays are difficult to reach is difficult. Moreover, the sealing layer only seals the outer periphery, and in that case, an inert gel or the like that fills the internal space is filled inside the outer peripheral sealing layer. However, when the area of the element is increased, the element is not effectively sealed by the method using the outer peripheral sealing layer.

  On the other hand, Patent Document 2 discloses a method for producing an organic EL device using a specific photocurable resin composition as a method that can be applied to an opaque portion. A manufacturing method is disclosed in which a photocurable resin composition is applied, irradiated with ultraviolet rays, and immediately after light irradiation, a glass substrate and a thin film structure are bonded together and heated to seal. However, in this production method, the method for applying the resin composition onto the substrate is not clearly described. In general, when coating is performed on the entire surface of a substrate, the coating time increases as the coating area increases, which is not preferable. In addition, the photocurable resin composition uses a curing control agent to delay the curing, but if the amount of the curing control agent used is increased in order to increase the pot life due to the necessity of alignment adjustment, etc. It adversely affects the physical properties of the cured product and is not preferable.

By the way, in the structure of the top emission type organic EL element, the organic laminate is usually sandwiched between two moisture-proof substrates such as glass, and the moisture-proof substrates are sealed with a sealing material. As described above, the conventional organic EL element is a type in which a sealing adhesive is applied and bonded to the periphery of the substrate. However, when the element is enlarged, not only the periphery of the substrate but also the entire surface of the substrate is sealed. Is effective for moisture resistance. In addition, according to the structure of the top emission type organic EL element, the sealing material needs to be transparent, and when the ultraviolet ray is irradiated in a large amount, the element may be damaged. A simple manufacturing method is desirable.
JP 2004-335207 A JP 2005-336314 A

  In view of the above-mentioned present situation, an object of the present invention is to sufficiently use an electronic device having a structure in which two substrates are sealed with a photo-curable sealing material with a narrow gap without using a curing control agent. It is possible to precisely control the gap and adjust the alignment by using a photo-curable resin composition that can secure the time, and also exhibits a sufficient sealing effect even for electronic devices with a large element area. It is to provide a possible manufacturing method.

  The present invention is a method for manufacturing an electronic device having a structure in which two substrates are sealed with a photocurable sealing material, and (A) a monofunctional group containing a hydroxyl group in at least one of the two substrates. 20-80 parts by weight of an oxetane compound, (B) 80-20 parts by weight of a polyfunctional oxetane compound or polyfunctional epoxy compound, and (C) a sulfonium salt-type photocationic polymerization initiator whose counter anion is antimonate or phosphate (A) and (B) a step (a) of applying a photocurable sealing material composition containing 0.1 to 10 parts by weight with respect to a total of 100 parts by weight over the entire coated surface at equal intervals (a), After the step (b) of irradiating the composition with ultraviolet rays, the step (c) of bonding the two substrates with the composition sandwiched between the step (b), and the two bonded substrates Between boards A step (d) of curing the composition by UV irradiation and / or heating, and after step (b) and before step (d) at room temperature and / or Or it is the manufacturing method of the electronic device characterized by adjusting alignment.

The present invention exhibits the following effects by the above-described configuration.
(1) The production method of the present invention can precisely perform gap control and alignment adjustment by using a photocurable resin composition that can ensure a sufficient pot life without using a curing control agent. In addition, the sealing effect can be sufficiently exhibited even for an electronic device having a large element area or an enlarged electronic device.
(2) In the production method of the present invention, in particular, an opaque substrate such as an organic EL element for top emission can be entirely sealed with a photocurable resin composition with a small amount of light irradiation.

  The photocurable resin composition used in the present invention comprises (A) 20 to 80 parts by weight of a monofunctional oxetane compound containing a hydroxyl group, and (B) 80 to 20 parts by weight of a polyfunctional oxetane compound or a polyfunctional epoxy compound. And (C) 0.1 to 10 parts by weight of (A) and (B) a total of 100 parts by weight of a sulfonium salt-type photocationic polymerization initiator whose counter anion is antimonate or phosphate.

  The monofunctional oxetane compound (A) containing a hydroxyl group is not particularly limited as long as it is a compound having one oxetanyl group in the molecule and containing a hydroxyl group. For example, 3-ethyl-3-hydroxy There is methyl oxetane, but it is not limited to this.

  The content is 20 to 80 parts by weight in a total of 100 parts by weight of (A) and (B). If the content is less than 20 parts by weight, sufficient curing retardation cannot be obtained, and if it exceeds 80 parts by weight, the curability is deteriorated. The lower limit is preferably 25 parts by weight, and the upper limit is preferably 70 parts by weight.

  As the polyfunctional oxetane compound or polyfunctional epoxy compound (B), a bifunctional or higher functional oxetane compound or epoxy compound can be used. Examples of the bifunctional or higher oxetane compound, that is, a compound having two or more oxetanyl groups in the molecule include di [1-ethyl (3-oxetanyl)] methyl ether, 1,4-bis [(1-ethyl- 3-oxetanyl) methoxy] benzene, 1,3-bis [(1-ethyl-3-oxetanyl) methoxy] benzene, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxy] biphenyl, and the like. . The polyfunctional oxetane compound is preferably a bifunctional compound, and when a trifunctional or higher functional compound is used, the blending amount thereof is preferably 30% by weight or less, more preferably 20% by weight or less in the bifunctional or higher functional oxetane compound. . When a tri- or higher functional oxetane compound is used in an amount exceeding 30% by weight, the viscosity becomes high, sufficient curing retardation cannot be obtained, and the obtained cured product tends to be hard and brittle.

  Examples of the bifunctional or higher functional epoxy compound, that is, a compound having two or more epoxy groups in the molecule include, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, hydrogenated bisphenol A type epoxy resin. Etc. The polyfunctional epoxy compound is preferably a bifunctional one, and the blending amount of the trifunctional or higher functional epoxy compound is preferably 30% by weight or less, more preferably 20% by weight or less in the bifunctional or higher functional epoxy compound. When a trifunctional or higher functional epoxy compound is used in excess of 30% by weight, the viscosity becomes high, sufficient curing retardance cannot be obtained, and the obtained cured product tends to be hard and brittle.

  Content of a polyfunctional oxetane compound or a polyfunctional epoxy compound (B) is 80-20 weight part in a total of 100 weight part of (A) and (B). When the content exceeds 80 parts by weight, the curing retardation is reduced, and when it is less than 20 parts by weight, sufficient curability cannot be obtained. The upper limit is preferably 70 parts by weight, and the lower limit is preferably 25 parts by weight.

  Examples of the sulfonium salt-type photocationic polymerization initiator (C) in which the counter anion is antimonate or phosphate include bis [4- (diphenylsulfonio) -phenyl] sulfide bis-hexafluorophosphate, bis [4- (Diphenylsulfonio) -phenyl] sulfide bis-hexafluoroantimonate, bis [4- (di (2-hydroxyethyl) phenyl) sulfonio-phenyl] sulfide bis-hexafluorophosphate, bis [4- (di (2 -Hydroxyethyl) phenyl) sulfonio-phenyl] sulfide bis-hexafluoroantimonate and the like. These can be used alone or in combination. Of these, fluorophosphates are more preferred.

  The content is 0.1 to 10 parts by weight with respect to 100 parts by weight in total of (A) and (B). Preferably it is 1-5 weight part.

  In the photocurable resin composition used in the present invention, a photosensitizer should not be used.

  Other additives can be used in the photocurable resin composition used in the present invention as long as the object of the present invention is not impaired. Examples of such additives include silane coupling agents, leveling agents, antifoaming agents, and pressure-sensitive adhesives. In particular, the addition of a silane coupling agent has the effect of improving the familiarity of the liquid resin, the inorganic filler, and the spacer. Examples of the silane coupling include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4- Epoxycyclohexyl) ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, mercaptosilane, sulfide silane, ureidosilane, aminosilane and the like.

  The blending amount of the other additives is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, in 100 parts by weight of the photocurable resin composition.

  There is no limitation in particular in the manufacturing method of the photocurable resin composition used in this invention, What is necessary is just to mix so that a raw material may mix uniformly. For example, the (A) component, the (B) component, and the photopolymerization initiator (C), and an inorganic filler, a coupling agent, a spacer, and other necessary components are mixed and mixed according to a conventional method under heating and reduced pressure. Stir and mix, defoam and dehydrate. As conditions, stirring and mixing are performed for 30 minutes to 2 hours under reduced pressure of 60 to 80 ° C. and 1 to 10 torr.

Next, each step of the present invention will be described.
Step (a) of applying the photocurable encapsulant composition on at least one of the two substrates at regular intervals over the entire coated surface (a)
Although the substrate varies depending on the electronic device, for example, a support substrate provided with an organic EL layer, a glass substrate for sealing, and the like when an organic EL element is taken as an example. The conceptual diagram of sealing of an organic EL element is shown in FIG.1 and FIG.2. The support substrate may be provided with a passivation film (FIG. 2). Organic EL elements include those provided with a passivation layer (inorganic layer), a color conversion filter layer, and a black matrix layer in addition to a structure in which a color conversion filter layer is bonded. In this case, the color conversion filter layer is a general term for a color filter layer, a fluorescence conversion layer, and a laminate of the color filter layer and the fluorescence conversion layer. The black matrix layer may be any layer that absorbs visible light well and does not adversely affect the light emitting portion and the color conversion filter layer. As the support substrate, an insulating substrate made of glass, plastic, or the like, or a substrate in which an insulating thin film is formed on a semiconductive or conductive substrate can be used. Alternatively, a flexible film formed from polyolefin, acrylic resin, polyester resin, polyimide resin, or the like may be used for the support substrate. The application target substrate may be both substrates to be attached, or may be either one, and application to one substrate is preferable from the viewpoint of simplifying the process.

  The photocurable encapsulant composition is applied over the entire application surface of the substrate. That is, it is not applied to only the outer peripheral portion, but applied over the entire area to be applied. The application target region may be the entire surface of the substrate or a part thereof. In the case of an organic EL element, the entire surface of the substrate is usually the application target region. In the present invention, the application is performed by spot application as illustrated in FIG. As shown in FIG. 4, the application is performed by, for example, spot application on a glass substrate using a dispenser. That is, instead of line coating or surface coating, the encapsulant resin is applied to the entire surface of the coating surface at regular intervals in a spot shape. Point application has the advantage that the application amount is easy to control and the application speed is fast, and the line application tends to reduce the application amount at the start and end points, and tends to increase the application amount when bending the line, Surface coating is slow in coating speed. In addition, equidistant point application has an advantage that the encapsulant composition can be spread over the entire application surface during bonding. The application may be performed by any technique capable of applying an equal amount of dots at equal intervals at high speed, and is preferably a jet dispenser, an inkjet dispenser, or the like. The application amount and the point application interval are preferably adjusted so that the encapsulant spreads over the entire application surface during bonding, taking into account the viscosity of the encapsulant composition, as the viscosity of the encapsulant composition Is preferably 300 mPa · s (25 ° C.) or less, and more preferably 100 mPa · s (25 ° C.) or less, from the viewpoints of controlling the coating speed and coating amount, developing on the coating surface and preventing air entrainment. The coating amount is preferably controlled so that the coating thickness is 60 μm or less when the encapsulant is spread over the entire coated surface from the viewpoint of preventing air bubbles from being caught. Moreover, it is also preferable to apply under reduced pressure in order not to generate bubbles in the encapsulant composition.

  Moreover, in this invention, the adhesive agent for dams can be apply | coated to the outer periphery part on a board | substrate before the said process (a). As shown in FIG. 2 and FIG. 3, the dam adhesive means that the adhesive is applied in a bank shape around the application target region. Then, the sealing material composition is spot-coated on the entire inner surface of the dam. By doing so, the sealing material composition does not protrude when bonded, and the gap between the substrates can be easily controlled by adjusting the thickness of the coating layer when a passivation film is formed. The adhesive for dams may be a thermosetting type, a UV curing type, a UV + thermosetting type, or a two-component mixed room temperature curing type. In the case of a thermosetting type adhesive or a two-component mixed room temperature curing type adhesive, it is preferable to perform a curing treatment in advance after application. In the case of a photocurable resin composition, it may be cured in advance or may be cured together with the curing treatment of the sealing material composition. Application | coating should just be the method in which line application is possible. The viscosity of the adhesive for dams is preferably 30,000 mPa · s (25 ° C.) or more, and the upper limit is preferably 1,000,000 mPa · s.

(B) irradiating the applied composition with ultraviolet rays
Ultraviolet irradiation can be performed so that a relatively small amount of irradiation is applied, for example, an irradiation energy of about 100 to 4000 mJ / cm ² , preferably 300 to 3000 mJ / cm ² . As the irradiation device, for example, an ultraviolet lamp (xenon lamp, xenon-mercury lamp, metal halide lamp, etc.), an arc type irradiation device, or the like can be used. By this irradiation, the encapsulant composition is not immediately cured, and in the case of the photo-curable resin composition, the pot life can be 3 minutes or longer, for example, about 60 minutes or longer.

After the step (b), the step (c) of bonding the two substrates with the composition interposed therebetween.
The substrate irradiated with ultraviolet rays is bonded to another substrate with a sealing material composition interposed therebetween, and sealed. Bonding may be performed under normal pressure or reduced pressure, and may be performed in a nitrogen atmosphere. It is preferable to carry out under reduced pressure in order not to generate bubbles in the encapsulant composition. Moreover, in order to expand | deploy a sealing material composition as needed, a board | substrate can be pressurized and bonded together.

Step (d) of curing the composition between two bonded substrates by ultraviolet irradiation and / or heating.
Since the photocurable resin composition usually takes a long time to cure at room temperature, it is preferably cured in a short time so that the bonded substrates are not displaced. , UV irradiation and / or heating. That is, only ultraviolet irradiation, only heating, or a combination of ultraviolet irradiation and heating can be used, and among these, the combined use of ultraviolet irradiation and heating is preferable. The heating is preferably 90 ° C. or less, and more preferably about 80 ° C. The heating time is preferably 10 to 120 minutes, more preferably 30 to 60 minutes. The irradiation with ultraviolet rays is preferably about 500 to 6000 mJ / cm ² , and more preferably 3000 to 6000 mJ / cm ² . When ultraviolet irradiation and heating are used in combination, the ultraviolet irradiation is preferably about 500 to 3000 mJ / cm ² and the heating time is 10 to 30 minutes.

  In the present invention, after the step (b) and before the step (d), preferably after the step (c), the gap and / or alignment between the substrates is adjusted at room temperature. In the case of an organic EL element, particularly a color organic EL element, it is necessary to precisely adjust the alignment between the light emitting portion of the organic EL element and the color conversion filter layer. The gap between the substrates is preferably 30 μm or less, more preferably 20 μm or less. For example, the gap may be adjusted by applying a pressure to the substrate so that an appropriate interval is obtained. In a precision element such as an organic EL element, such adjustment can be performed precisely, and it is necessary to complete sealing without impairing the gap or alignment. In the present invention, since the pot life of the encapsulant composition is sufficiently long and low viscosity can be realized, it is possible to precisely control the gap with such a narrow gap.

  The manufacturing method of the present invention can be widely applied to electronic devices having a structure in which two substrates are sealed with a photocurable sealing material. In particular, it can be suitably applied to an organic EL element, especially a top emission organic EL element. Sealing can be used not only for direct application to an organic EL laminated light emitter, but also for bonding an inorganic film formed on an organic EL laminated light emitter to a glass substrate. Furthermore, it is applicable not only to organic EL elements but also to liquid crystal display devices, electronic paper, organic transistors, organic solar cells, organic EL lighting, and the like.

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Hereinafter, a part shows a weight part.

The meanings of the abbreviations are as follows.
EPC-835LV: A mixture of bisphenol A epoxy resin and bisphenol F epoxy resin. A bifunctional epoxy compound manufactured by Dainippon Ink & Chemicals, Inc.
OXT-101: 3-ethyl-3-hydroxymethyloxetane. Hydroxyl-containing monofunctional oxetane compound manufactured by Toagosei Co., Ltd.
OXT-212: 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane. Monofunctional oxetane compound manufactured by Toa Gosei Co., Ltd.
OXT-221: Di [1-ethyl (3-oxetanyl)] methyl ether. A bifunctional oxetane compound manufactured by Toa Gosei Co., Ltd.
TONE0310: TONE Polyol0310. A trifunctional caprolactone polyol manufactured by Dow Chemical Japan Co., Ltd.
DEX-146: P-tertiary butyl phenyl glycidyl ether. Monofunctional epoxy compound manufactured by Nagase ChemteX Corporation.
UVI6992: a mixture of triallylsulfonium hexafluorophosphate. Photo cationic polymerization initiator manufactured by Dow Chemical Japan Co., Ltd.
UVI6976: a mixture of triallylsulfonium hexafluoroantimonate. Photo cationic polymerization initiator manufactured by Dow Chemical Japan Co., Ltd.
A2074: Photoinitiator 2074 (trade name), a photocationic polymerization initiator manufactured by Rhodia Japan.

Examples 1-6, Comparative Examples 1-6
The sealing material composition was adjusted with the formulation shown in Table 1. The following items were evaluated for each composition. The results are shown in Table 1.

<Evaluation method>
Delay curing time: The encapsulant composition is spot-coated on two alkali glass plates with an ink jet dispenser so as to have a thickness of about 20 μm, and ultraviolet rays are applied to both glasses at an irradiation energy of 50 mW / cm ² for 10 seconds. Irradiated and bonded together. The point of time when the bonded glass did not shift when it was left at an angle of 45 degrees was defined as the delay hardening time (minutes).
Curability: 6 J / cm ² + 80 ° C./10 min.
Viscosity: An E-type (L type) rotary viscometer was used to measure the viscosity of the liquid composition adjusted to 25 ° C. at a rotation speed of 5 rpm.

The conceptual diagram of 1 aspect of the structure of the organic EL element manufactured with the manufacturing method of this invention. The conceptual diagram of the other aspect of the organic EL element manufactured with the manufacturing method of this invention. It is the aspect which uses the adhesive agent for dams, and is a conceptual diagram in case the passivation film is formed in the organic EL element. The conceptual diagram of 1 aspect of point application | coating and application | coating of the adhesive agent for dams. The conceptual diagram of the process (a) and process (b) of this invention.

Explanation of symbols

10. Glass substrate 11. Support substrate 12. 12. Sealant composition Organic EL phosphor layer 14. Dam adhesive 15. Passivation film 20. Point-sealed encapsulant composition 30. Dispenser 40. UV irradiation

Claims (6)

  A method of manufacturing an electronic device having a structure in which two substrates are sealed with a photocurable sealing material, wherein (A) a monofunctional oxetane compound containing a hydroxyl group is added to at least one of the two substrates. -80 parts by weight, (B) 80-20 parts by weight of a polyfunctional oxetane compound or polyfunctional epoxy compound, and (C) a sulfonium salt-type photocationic polymerization initiator whose counter anion is antimonate or phosphate (A) And (B) a step (a) of applying a photocurable sealing material composition containing 0.1 to 10 parts by weight with respect to a total of 100 parts by weight over the entire coating surface at equal intervals, and the applied composition After the step (b) of irradiating the substrate with ultraviolet rays, the step (c) of bonding the two substrates with the composition interposed therebetween, and the step between the two substrates bonded together. composition Step (d) of curing the substrate by ultraviolet irradiation and / or heating, and after step (b) and before step (d), at room temperature, gaps and / or alignments between the substrates are formed. A method of manufacturing an electronic device, characterized by adjusting.   The manufacturing method of Claim 1 which performs the bonding process (c) of a board | substrate under pressure reduction.   The manufacturing method according to claim 1, wherein the gap and / or alignment between the substrates is adjusted so that the gap between the substrates is kept at 30 μm or less.   Before the step (a), a step of applying a dam adhesive to the outer peripheral portion on the substrate is included, and the photocurable sealing material composition is spot-coated on the entire surface surrounded by the dam adhesive. The manufacturing method in any one of Claims 1-3.   The production method according to claim 1, wherein in step (d), the composition is heated and cured after irradiation with ultraviolet rays. The electronic device is an organic EL element for top emission, and the photocurable sealing material composition is applied to both the supporting substrate and the opaque sealing substrate forming the organic EL element, or only to the opaque sealing substrate. The manufacturing method in any one of Claims 1-5 applied.

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