Dry film, light-emitting electronic component, and method for manufacturing a light-emitting electronic component

Abstract

This reduces peeling and cracking of wiring patterns and forms a dry film curing layer with high chemical resistance. [Solution] The present invention relates to a dry film 1 which is pressed onto an element-equipped substrate 2 in which the light-emitting surfaces of a plurality of light-emitting elements 21, 22, 23 are fixed to a substrate 20 from the electrode 25 side opposite to the light-emitting surface, and comprises a curable resin layer 9, the curable resin layer 9 comprising a curable resin composition, a filler having radical polymerizable functional groups on its surface, and a polymerization initiator, and a cured film of the dry film 1, and a method for manufacturing the light-emitting electronic component.

Description

[Technical Field]

[0001] The present invention relates to a dry film, a light-emitting electronic component, and a method for manufacturing a light-emitting electronic component. [Background technology]

[0002] Light-emitting diodes (LEDs), such as mini-LEDs and micro-LEDs, have been trending towards miniaturization in recent years. When LEDs are used in displays, reducing the size of the light-emitting unit is expected to lead to higher resolution, higher image quality, and other improvements. On the other hand, the size of displays is trending towards larger sizes compared to conventional displays. However, arranging many micro-LEDs individually on a circuit board to accommodate large displays requires advanced technology and high manufacturing costs.

[0003] To solve these problems, a technique has been devised to fix multiple micro-LEDs onto a small substrate, that is, a packaging technique for tiny light-emitting elements such as MIP (MicroLED in Package) elements. For example, since an MIP element contains multiple micro-LEDs on a single substrate, it is simpler to arrange an MIP element on a circuit board than to arrange individual micro-LEDs on a substrate.

[0004] Thus, light-emitting electronic components, such as the light-emitting element package exemplified above, are expected to improve the ease of mounting and reduce costs when using light-emitting elements in large displays. When manufacturing such light-emitting electronic components, a method of forming a flat layer of black matrix between light-emitting elements to block light is known (see Patent Document 1). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Chinese Patent Application Publication No. 113257964A [Overview of the project] [Problems that the invention aims to solve]

[0006] In the conventional light-emitting electronic components described above, it is necessary to encapsulate the light-emitting element with a dry film and then pattern electrodes and wiring on the cured dry film.

[0007] However, in processes such as forming photoresists for electrode and wiring patterns, removing the photoresists, and plating, the dry film cured film requires high chemical resistance. When fillers are added to the cured film to reduce peeling of wiring patterns or cracking of wiring patterns, there is a problem that the interface between the resin, which constitutes the cured film, and the fillers dispersed in the resin becomes susceptible to chemical damage.

[0008] Therefore, the present invention aims to reduce peeling and cracking of wiring patterns and to form a dry film cured film with high chemical resistance. [Means for solving the problem]

[0009] (1) A dry film according to one embodiment for achieving the above objective is a dry film that is pressed onto an element-equipped substrate, in which the light-emitting surface side of a plurality of light-emitting elements is fixed to the substrate, from the electrode side opposite to the light-emitting surface, The dry film comprises a curable resin layer, The dry film is characterized in that the curable resin layer comprises a curable resin composition, a filler having radical polymerizable functional groups on its surface, and a polymerization initiator. (2) In a dry film according to another embodiment, preferably the filler may be an inorganic filler. (3) In a dry film according to another embodiment, preferably the inorganic filler may be silica. (4) In a dry film according to another embodiment, preferably the average particle size of the inorganic filler is 100 μm or less. (5) In a dry film according to another embodiment, preferably the amount of inorganic filler added may be 40 to 95 parts by mass per 100 parts by mass of the total resin solids of the curable resin layer. (6) In a dry film according to another embodiment, preferably the curable resin composition may contain a polyfunctional epoxy resin. (7) In a dry film according to another embodiment, preferably the amount of the polyfunctional epoxy resin blended may be 10 to 60 parts by mass per 100 parts by mass of the total resin solids content of the curable resin layer. (8) In a dry film according to another embodiment, preferably the curable resin layer may contain an elastomer. (9) In a dry film according to another embodiment, preferably the amount of elastomer blended is 0.1 to 20 parts by mass per 100 parts by mass of the total resin solids of the curable resin layer. (10) In a dry film according to another embodiment, preferably the polymerization initiator may be a cationic polymerization initiator that generates radicals during cationic polymerization. (11) In a dry film according to another embodiment, preferably the amount of polymerization initiator blended may be 0.001 to 5 parts by mass per 100 parts by mass of the total resin solids of the curable resin layer. (12) In a dry film according to another embodiment, preferably the curable resin layer may be formed by laminating a first curable resin layer located on the side closer to the light-emitting surface and a second curable resin layer located on the side closer to the electrode. (13) In a dry film according to another embodiment, preferably the coefficient of linear expansion of the second curable resin layer after curing is 90 ppm / K or less. (14) In a dry film according to another embodiment, preferably, both the first curable resin layer and the second curable resin layer contain an inorganic filler, and the inorganic filler content of the second curable resin layer may be greater than the inorganic filler content of the first curable resin layer. (15) In the dry film according to another embodiment, preferably, the storage modulus of the second curable resin layer may be greater than that of the first curable resin layer. (16) In the dry film according to another embodiment, preferably, at 100 ° C, the storage modulus of the second curable resin layer is greater than that of the first curable resin layer, and at 150 ° C, the storage modulus of the second curable resin layer may be greater than that of the first curable resin layer. (17) In the dry film according to another embodiment, preferably, the storage modulus of the first curable resin layer is 1.0×10 5 Pa or less at 100 °C. (18) In the dry film according to another embodiment, preferably, the storage modulus of the second curable resin layer is 1.0×10 7 Pa or less at 100 °C. (19) In the dry film according to another embodiment, preferably, the storage modulus of the second curable resin layer is 1.0×10 5 Pa or more at 150 °C. (20) In the dry film according to another embodiment, preferably, at least one of the first curable resin layer and the second curable resin layer may contain a modified elastomer having a functional group capable of reacting with an epoxy group. (21) In the dry film according to another embodiment, preferably, the first curable resin layer may contain a modified elastomer having a functional group capable of reacting with an epoxy group. (22) In the dry film according to another embodiment, preferably, the second curable resin layer may contain a modified elastomer having a functional group capable of reacting with an epoxy group. (23) In the dry film according to another embodiment, preferably, the modified elastomer having a functional group capable of reacting with an epoxy group may be an acid-modified elastomer. In the dry film according to another embodiment, preferably, the modified elastomer having a functional group reactive with the epoxy group may be acrylonitrile-butadiene rubber. In the dry film according to another embodiment, preferably, at least the second curable resin layer may contain carbon black. In the dry film according to another embodiment, preferably, the carbon black may be gas black. In the dry film according to another embodiment, preferably, the first curable resin layer may not contain an inorganic filler. The dry film cured product after curing the dry film according to one embodiment for achieving the above object may be obtained by curing the curable resin layer of the dry film. (29) The light-emitting electronic component according to one embodiment for achieving the above object is a substrate with elements in which the light-emitting surfaces of a plurality of light-emitting elements are fixed to a substrate, a dry film cured product which is a film after curing any of the above dry films and is pressure-bonded to the surface of the substrate with elements on which the plurality of light-emitting elements are arranged, and includes. (30) The method for manufacturing a light-emitting electronic component according to one embodiment for achieving the above object is a step of pressure-bonding any of the above dry films to the surface of the substrate with elements on which the plurality of light-emitting elements are arranged, on the side where the plurality of light-emitting elements of the substrate with elements in which the light-emitting surfaces of the plurality of light-emitting elements are fixed to the substrate are arranged, a step of filling the curable resin layer between the plurality of light-emitting elements, a step of curing the curable resin layer, and includes. (31) In the method for manufacturing a light-emitting electronic component according to another embodiment, preferably, the thickness of the second curable resin layer before the pressure bonding may be 10 to 150% with respect to the height of the light-emitting element. (32) In a method for manufacturing a light-emitting electronic component according to another embodiment, preferably the thickness of the first curable resin layer before pressing may be 10 to 200% of the height of the light-emitting element. (33) In a method for manufacturing a light-emitting electronic component according to another embodiment, preferably the total thickness of the first curable resin layer and the second curable resin layer before bonding is 80 to 300% of the height of the light-emitting element. [Effects of the Invention]

[0010] According to the present invention, it is possible to reduce peeling and cracking of wiring patterns and to form a dry film cured film with high chemical resistance. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 shows a cross-sectional view of a dry film according to one embodiment, when it is cut in the thickness direction. [Figure 2] Figure 2 shows a cross-sectional view identical to Figure 1 of a substrate with an element used in the manufacture of a light-emitting electronic component according to one embodiment. [Figure 3] Figure 3 shows a cross-sectional view identical to Figure 1, when the dry film of Figure 1 is positioned so that its first curable resin layer is in contact with the top surface of the light-emitting element of the substrate with the element shown in Figure 2. [Figure 4] Figure 4 shows a cross-sectional view identical to Figure 1, showing the state in which the dry film has been pressed onto the substrate with the elements attached, progressing from the stage in Figure 3 to the point where the first curable resin layer and the second curable resin layer in Figure 1 are embedded between the light-emitting elements. [Figure 5] Figure 5 shows a cross-sectional view identical to Figure 1, showing the state after further progress from the stage in Figure 4, where the protective sheet on the second curable resin layer has been peeled off and the curing treatment has been performed. [Figure 6] Figure 6 shows a cross-sectional view of the light-emitting electronic component, identical to that of Figure 1, after further etching from the stage shown in Figure 5, exposing at least a portion of the electrodes of the light-emitting element. [Modes for carrying out the invention]

[0012] Next, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below are not intended to limit the invention as defined in the claims, and not all elements and combinations thereof described in the embodiments are necessarily essential to the solution of the present invention. In this specification, "main component" means a component that accounts for 50% or more by mass of the total solid content of the entire composition. In this specification, "total resin solids" means the total solid mass of the resin and elastomer, and if a curing agent is included in addition to the elastomer, it also includes the solid mass of the curing agent. A numerical range represented by "~" means a numerical range where the numbers before and after "~" are the lower and upper limits. "Amount of compounding" may be read as "content."

[0013] Figure 1 shows a cross-sectional view of a dry film according to one embodiment, cut in the thickness direction. Figure 2 shows a cross-sectional view identical to Figure 1 of a substrate with an element used in the manufacture of a light-emitting electronic component according to one embodiment. Figure 3 shows a cross-sectional view identical to Figure 1 when the dry film of Figure 1 is placed so that its first curable resin layer is in contact with the top surface of the light-emitting element of the substrate with an element shown in Figure 2. Figure 4 shows a cross-sectional view identical to Figure 1, showing the dry film pressed onto the substrate with an element, progressing from the stage in Figure 3, to the point where the first curable resin layer and the second curable resin layer of Figure 1 are embedded between the light-emitting elements. Figure 5 shows a cross-sectional view identical to Figure 1, showing the state after further progress from the stage in Figure 4, where the protective sheet on the second curable resin layer has been peeled off and curing treatment has been performed. Figure 6 shows a cross-sectional view identical to Figure 1 of a light-emitting electronic component, showing the state after further progress from the stage in Figure 5, where etching treatment has been performed and at least a part of the electrodes of the light-emitting element is exposed.

[0014] 1. Dry film The dry film 1 according to this embodiment is a film that is pressed onto an element-equipped substrate 2, in which the light-emitting surfaces 24 side of a plurality of light-emitting elements 21, 22, 23 are fixed to a substrate 20, from the electrode 25 side opposite to the light-emitting surface 24. The dry film 1 comprises a curable resin layer 9 containing a curable resin composition. The curable resin layer 9 contains a curable resin composition, a filler having radical polymerizable functional groups on its surface, and a polymerization initiator. Preferably, the dry film 1 is a laminate comprising a first curable resin layer 10 and a second curable resin layer 11 as the curable resin layer 9. The first curable resin layer 10 is a layer that is positioned on the side closer to the light-emitting surface 24 when filled into the element-equipped substrate 2. The second curable resin layer 11 is a layer that is positioned on the side closer to the electrode 25 when filled into the element-equipped substrate 2. However, the curable resin layer 9 may consist of only one of either the first curable resin layer 10 or the second curable resin layer 11. Dry film 1 is the state before the curing process of the dry film cured product 3 provided in the light-emitting electronic component 5 described later. That is, the curable resin layer 9 of dry film 1 is in an uncured state until the curing process described later is performed. In the pressing process described later, dry film 1 is positioned so that the first curable resin layer 10 side is in contact with the electrodes 25 of the multiple light-emitting elements 21, 22, and 23. The coefficient of linear expansion (also called the coefficient of linear thermal expansion, CTE or CLTE; the same applies hereinafter) of the cured film of the second curable resin layer 11 is smaller than the coefficient of linear expansion of the cured film of the first curable resin layer 10. Preferably, the storage modulus of dry film 1 is different between the second curable resin layer 11 and the first curable resin layer 10. More preferably, the storage modulus of the second curable resin layer 11 is greater than the storage modulus of the first curable resin layer 10.

[0015] The dry film 1 may further have protective sheets on the outer surface of either or both of the first curable resin layer 10 and the second curable resin layer 11 for ease of handling. Figure 1 shows an example of the dry film 1 having protective sheets 12 and 13 on the outer surfaces of both the first curable resin layer 10 and the second curable resin layer 11. More specifically, the dry film 1 has a structure in which protective sheet 13, the second curable resin layer 11, the first curable resin layer 10, and protective sheet 12 are laminated in that order. Each layer constituting the dry film 1 will be described below.

[0016] (1) First curable resin layer The first curable resin layer 10 is a layer that, in the crimping and filling processes described later, sufficiently fills the spaces between the multiple light-emitting elements 21, 22, and 23 arranged on the element-equipped substrate 2, preventing appearance defects due to expansion of unfilled voids during the curing process and damage to the light-emitting elements 21, 22, and 23 due to external factors in subsequent processes.

[0017] [Storage modulus] The storage modulus of the first curable resin layer 10 is different from the storage modulus of the second curable resin layer 11, which will be described later. The storage modulus of the first curable resin layer 10 may be smaller or larger than the storage modulus of the second curable resin layer 11, but it is preferably smaller than the storage modulus of the second curable resin layer 11, and more preferably smaller than the storage modulus of the second curable resin layer 11 at 100°C and 150°C.

[0018] When the storage modulus of the first curable resin layer 10 is greater than that of the second curable resin layer 11, the following advantages are obtained. In the crimping and filling process described later, the presence or absence of the light-emitting elements 21, 22, and 23 can cause deformation of the second curable resin layer 11 due to the difference in height. In contrast, the first curable resin layer 10 provides support, making it less likely for irregularities to occur due to the deformation of the layer 11, and thus improving the smoothness after curing.

[0019] If the storage modulus of the first curable resin layer 10 is smaller than that of the second curable resin layer 11, in the subsequent pressing and filling process, the first curable resin layer 10 will be pressed in by the second curable resin layer 11, allowing for sufficient filling between the multiple light-emitting elements 21, 22, and 23.

[0020] The storage modulus of the first curable resin layer 10 is preferably 1.0 × 10 at 100°C. 5 It is less than or equal to Pa, and more preferably 1.0 × 10⁻⁶ 2 Pa~1.0×10 5 Pa is more preferably 1.0 × 10 3 Pa~5.0×104 It is Pa.

[0021] Since the storage elastic modulus of the first curable resin layer 10 at 100 °C is below the preferable upper limit value, sufficient fluidity can be obtained when pressure-bonding to the substrate 2 with elements, and it can fully fill the spaces between the plurality of light-emitting elements 21, 22, 23 following the unevenness of the substrate 2 with elements by the plurality of light-emitting elements 21, 22, 23. Since the storage elastic modulus of the first curable resin layer 10 at 100 °C is above the preferable lower limit value, uneven pressure during thermocompression bonding can be prevented, and a uniform appearance can be maintained. Also, outflow of the resin outside the range can be prevented, and the film thickness after pressure-bonding can be ensured.

[0022] The storage elastic modulus of the first curable resin layer 10 is preferably 5.0×10 5 Pa or less at 150 °C, more preferably 5.0×10 2 Pa to 5.0×10 5 Pa, and even more preferably 1.0×10 3 Pa to 1.0×10 5 Pa.

[0023] Since the storage elastic modulus of the first curable resin layer 10 at 150 °C is below the preferable upper limit value, cracks due to curing shrinkage are less likely to occur during thermosetting. Since the storage elastic modulus of the first curable resin layer 10 at 150 °C is above the preferable lower limit value, the flow during thermosetting can be suppressed, and appearance defects after curing such as repelling phenomenon are suppressed.

[0024] [Coefficient of linear expansion] The first curable resin layer 10 is a layer in which, after curing, the coefficient of linear expansion is in the range of 600 ppm / K or less, more preferably 300 ppm / K or less (for example, 1 ppm / K to 300 ppm / K), and even more preferably 180 ppm / K or less (for example, 3 ppm / K to 180 ppm / K). The coefficient of linear expansion of the first curable resin layer 10 after curing is greater than the coefficient of linear expansion of the second curable resin layer 11 after curing. The coefficient of linear expansion of the second curable resin layer 11 after curing is preferably 90 ppm / K or less, and more preferably 75 ppm / K or less, as will be described later. Note that the unit of the coefficient of linear expansion is 10 ppm / K or less. -6 It may also be expressed as / K. The coefficient of linear expansion in this application is measured in accordance with JIS K 7197, a standard for measuring the coefficient of linear expansion of resins.

[0025] [Curable resin composition] The first curable resin layer 10 is preferably composed of a thermosetting resin composition as the curable resin composition. Examples of thermosetting resin compositions include epoxy resin compositions, amide resin compositions, phenol resin compositions, polyimide resin compositions, maleimide resin compositions, cyanate resin compositions, and oxazine resin compositions.

[0026] Among the above resin compositions, epoxy resin compositions are preferred because they can achieve thermosetting properties at low temperatures and have excellent heat resistance and reliability. In this specification, an epoxy resin composition is a composition containing epoxy resin as the main component, or a composition containing epoxy resin and elastomer as the main components.

[0027] (Epoxy resin) In this specification and in the claims, an epoxy resin is a compound having epoxy groups in its molecule. In the present invention, epoxy resins having two or more epoxy groups in a single molecule are preferred. This is because a crosslinked structure can be formed through polymerization reactions between epoxy resins or reactions between the epoxy resin and a modified elastomer having functional groups that can react with epoxy groups, resulting in a cured product with high heat resistance. Furthermore, when an epoxy resin with two or more epoxy groups is used, the degree of crosslinking with the modified elastomer having functional groups that can react with epoxy groups is sufficient, resulting in a cured product with sufficient heat resistance.

[0028] In this embodiment, at least one of the first curable resin layer 10 and the second curable resin layer 11 described later preferably contains an epoxy resin.

[0029] Examples of epoxy resins include difunctional epoxy resins having two epoxy groups in the molecule, polyfunctional epoxy resins having three or more epoxy groups in the molecule, and high molecular weight epoxy resins having a weight-average molecular weight of 10,000 or more. Hydrogenated epoxy resins of these types may also be used. In this specification and the claims, epoxy resins with a weight-average molecular weight of 10,000 or more are classified as high molecular weight epoxy resins, regardless of the number of epoxy groups in the molecule, and are not classified as difunctional or polyfunctional epoxy resins. The weight-average molecular weight of the epoxy resin is the polystyrene-based molecular weight measured by gel permeation chromatography.

[0030] Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, or phenoxy resins which are high molecular weight versions thereof, and hydrogenated versions thereof; novolac type epoxy resins such as phenol novolac epoxy resin, o-cresol novolac epoxy resin, bisphenol A novolac epoxy resin, xylene structure-containing novolac epoxy resin, naphthol novolac type epoxy resin; glycidyl ester epoxy resins such as diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, p-hydroxybenzoate glycidyl ester, diglycidyl tetrahydrophthalate, diglycidyl succinate, diglycidyl adipic acid, diglycidyl sebacate, and triglycidyl trimellitic acid; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether Examples of epoxy resins include, but are not limited to, glycidyl ether-based epoxy resins such as glycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, sorbitol polyglycidyl ether, and polyglycerol polyglycidyl ether; glycidylamine-based epoxy resins such as triglycidyl isocyanurate and tetraglycidyldiaminodiphenylmethane; linear aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil; and special skeleton epoxy resins such as brominated bisphenol A type epoxy resin, phosphorus-containing epoxy resin, fluorine-containing epoxy resin, dicyclopentadiene skeleton-containing epoxy resin, naphthalene skeleton-containing epoxy resin, anthracene type epoxy resin, tert-butylcatechol type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, biphenyl type epoxy resin, and bisphenol S type epoxy resin.

[0031] As high molecular weight epoxy resins, phenoxy resins, epoxy-modified polybutadiene, copolymers of glycidyl methacrylate and methyl methacrylate, and modified polymers obtained by epoxy modification of other resins can be used. These epoxy resins may be used individually or in combination of two or more.

[0032] Among the epoxy resins mentioned above, the epoxy resin used in the first curable resin layer 10 is preferably a polyfunctional epoxy resin, from the viewpoint of increasing the crosslinking density after curing. Among polyfunctional epoxy resins, novolac-type epoxy resins in particular are epoxy resins that can introduce a moderately flexible skeleton and allow for adjustment of flexibility and softening point. As a result, the cured product is less prone to brittle fracture, the stability of the performance of the cured epoxy resin composition for long-term use is improved, and the crosslinking density can be increased. In addition, the heat resistance of the cured product is also improved.

[0033] Specific examples of novolac-type epoxy resins include, for example, "YX7700" from Mitsubishi Chemical Corporation, "NC7000L," "XD1000," and "EOCN-1020" from Nippon Kayaku Co., Ltd., "ESN485" from Nippon Steel Chemical & Material Co., Ltd., and "HP-7200H," "N-690," and "N-695" from DIC Corporation.

[0034] The amount of polyfunctional epoxy resin blended in the first curable resin layer 10 is preferably 10 to 99 parts by mass, more preferably 40 to 95 parts by mass, and even more preferably 60 to 90 parts by mass, based on 100 parts by mass of the total resin solids content of the first curable resin layer 10. If the amount of polyfunctional epoxy resin blended is above the lower limit, the crosslinking density can be increased to impart chemical resistance and heat resistance. If the amount of polyfunctional epoxy resin blended is below the upper limit, the storage modulus during thermocompression bonding can be adjusted, and the fluidity of the first curable resin layer 10 can be ensured.

[0035] From the viewpoint of ensuring sufficient fluidity during thermocompression bonding, it is preferable that the first curable resin layer 10 contains an epoxy resin with a softening point or melting point of 100°C or lower. From the viewpoint of handling properties and heat resistance of the cured product, it is more preferable that it contains an epoxy resin with a softening point or melting point of 50 to 95°C. By including an epoxy resin having a softening point or melting point within the above range, it becomes possible to control the storage modulus.

[0036] The total amount of epoxy resin in the first curable resin layer 10 is preferably 10 to 100 parts by mass, more preferably 20 to 99 parts by mass, and even more preferably 35 to 95 parts by mass, based on 100 parts by mass of the total resin solids in the first curable resin layer 10. When the total amount of epoxy resin is within the above range, it is possible to control the storage modulus and ensure appropriate fluidity during heat bonding. Furthermore, when the total amount of epoxy resin is above the lower limit, the heat resistance after curing can be improved.

[0037] (Elastomer) The first curable resin layer 10 preferably contains an elastomer in addition to a resin such as epoxy resin. Including an elastomer facilitates control of the storage modulus, i.e., control of fluidity. The elastomer may be a material included in the concept of a curable resin composition, or a material not included in the concept of a curable resin composition.

[0038] As the elastomer, a thermosetting elastomer, generally called "rubber," is preferred because it provides excellent heat resistance. Examples of thermosetting elastomers include acrylonitrile butadiene rubber (NBR), which is a random copolymer of butadiene and acrylonitrile, acrylic rubber, styrene butadiene rubber, vinyl acetate resin, and silicone resin. Among these, NBR is preferred because it has good compatibility with epoxy resin, allows control of the fluidity of the first curable resin layer 10 around 100°C, and has good adhesion to the second curable resin layer 11 and the element-equipped substrate 2. When the elastomer has unsaturated bonds, such as NBR, it can be crosslinked with a polymerization initiator, improving heat resistance and making it easier to control mechanical properties.

[0039] The weight-average molecular weight of the elastomer is preferably 100,000 to 1,000,000, more preferably 120,000 to 500,000, and even more preferably 150,000 to 300,000. If the weight-average molecular weight of the elastomer is within the above range, the storage modulus of the first curable resin layer 10 can be controlled, and fluidity during thermal bonding can be ensured. If the weight-average molecular weight of the elastomer is below the above upper limit, the compatibility with the epoxy resin is improved, and the flow during thermal curing can be controlled more effectively.

[0040] In particular, when the first curable resin layer 10 is composed of an epoxy resin composition, it is preferable to include a modified elastomer having a functional group that can react with epoxy groups, and more preferably to include NBR. If the modified elastomer has a functional group that can react with epoxy groups, it also acts as a curing agent for the epoxy resin. Furthermore, because it can react and bond with the epoxy resin, its heat resistance and reliability against thermal shock are improved. In addition, the difference in polarity between the functional group that can react with the epoxy resin and the resin skeleton has a good effect on dispersibility, and good dispersibility can be obtained when fillers or pigments are included in the first curable resin layer 10.

[0041] Functional groups that can react with epoxy groups include acidic groups such as carboxyl groups, sulfo groups, nitro groups, and phosphoric acid groups, as well as their acid anhydride groups, hydroxyl groups, and amino groups. Among these, acidic groups or acid anhydride groups are preferred because they allow curing at low temperatures and ensure a long pot life, and carboxyl groups or carboxylic acid anhydride groups are particularly preferred.

[0042] In other words, when the first curable resin layer 10 is composed of an epoxy resin composition, it preferably contains an acid-modified elastomer having acid groups or acid anhydride groups, more preferably an acid-modified elastomer having carboxyl groups, and even more preferably a modified NBR having carboxyl groups.

[0043] As modified NBR having a carboxyl group, carboxylated acrylonitrile rubber into which acrylic acid, methacrylic acid, maleic anhydride, etc. have been introduced is preferred. Examples of commercially available carboxylated acrylonitrile rubber include "NX775" and "1072CGJ" manufactured by Nippon Zeon Co., Ltd. Two or more modified elastomers having functional groups that can react with epoxy groups may be used in combination.

[0044] In this embodiment, at least one of the first curable resin layer 10 and the second curable resin layer 11 described later preferably includes a modified elastomer having a functional group that can react with epoxy groups.

[0045] The amount of elastomer in the first curable resin layer 10 is preferably 0.5 to 90 parts by mass, more preferably 1 to 80 parts by mass, and even more preferably 5 to 65 parts by mass, based on 100 parts by mass of the total resin solids content of the first curable resin layer 10. The amount of elastomer in the first curable resin layer 10 is preferably greater than the amount of elastomer in the second curable resin layer 11, which will be described later. When the amount of elastomer is within the above range, it is possible to control the storage modulus and ensure appropriate fluidity during heat bonding. Furthermore, when the amount of elastomer is above the lower limit, dispersibility is improved when fillers or carbon black are included. In addition, film-forming properties are improved, and the film thickness distribution can be narrowed when coating and forming an epoxy resin composition.

[0046] (Hardening agent) When the first curable resin layer 10 is composed of an epoxy resin composition, it may contain other curing agents for epoxy resins other than modified elastomers having functional groups that can react with epoxy groups. Examples of other curing agents include known curing agents such as phenolic curing agents, acid anhydride curing agents, and amine curing agents. Two or more of these other curing agents may be used in combination.

[0047] (curing catalyst) When the first curable resin layer 10 is composed of an epoxy resin composition, it may contain a curing catalyst that promotes the curing reaction of the epoxy resin. Preferred curing catalysts include imidazole-based, tertiary amine-based, phosphorus compound-based, and organic peroxide-based catalysts. Among these, imidazole-based or organic peroxide-based catalysts are preferred because they have good compatibility with epoxy resins and are less likely to cause yellowing. Suitable organic peroxides include, for example, benzoyl peroxide, di(2-t-butylperoxyisopropyl)benzene, 2,4-dichlorobenzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dicumyl peroxide, 2,5-dimethyl-bis(2,5-t-butylperoxy)hexane, di-t-butyl peroxide, t-butyl perbenzoate, and 1,6-hexanediol-bis-t-butyl peroxycarbonate. Among imidazole-based curing catalysts, those having a cyanoethyl group are particularly preferred because they dissolve easily in epoxy resins.

[0048] (Polymerization initiator) The first curable resin layer 10 contains a polymerization initiator. The polymerization initiator has the function of creating a chemical bond between the radical polymerizable functional group and the resin component of the first curable resin layer. The polymerization initiator is preferably a radical polymerization initiator, but may also be a cationic polymerization initiator that generates radicals. If it also acts as a curing catalyst for the epoxy resin composition, such as a cationic polymerization initiator, it is used as a polymerization initiator. Examples of radical polymerization initiators include water-soluble peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide; organic peroxides such as benzoyl peroxide, t-butyl hydroperoxide, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, and peroxyester; and azo compounds such as azobisisobutyronitrile. Examples of cationic polymerization initiators include sulfonium salts and iodonium salts. The amount of polymerization initiator added is preferably 0.001 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the total resin solids of the first curable resin layer 10. When the amount added is within the above range, curing can proceed sufficiently and the pot life of the dry film 1 can be ensured. Two or more polymerization initiators may be used in combination. Examples of polymerization initiators include "Perbutyl® P" manufactured by NOF Corporation and "San-Aid SI-110" manufactured by Sanshin Chemical Industry Co., Ltd.

[0049] (Filler) The first curable resin layer 10 preferably contains a filler (excluding the pigment described later) as long as it does not hinder sufficient filling of the spaces between the multiple light-emitting elements 21, 22, and 23 of the substrate 2 with the elements. In this embodiment, at least one of the first curable resin layer 10 and the second curable resin layer 11 described later contains a filler having radically polymerizable functional groups on its surface. The filler is preferably an inorganic filler. However, an organic material-based filler may also be used as the filler. There are no particular restrictions on the filler, but preferably inorganic fillers such as silica, talc, mica, alumina, and boron nitride are used. Examples of silica include fumed silica and colloidal silica. The filler is preferably surface-treated. Surface treatment of the filler improves its dispersibility and makes it easier to control its mechanical properties. Furthermore, by introducing functional groups that can react with epoxy resin or functional groups that can be radically polymerized through surface treatment, the interaction at the interface between the filler and the thermosetting resin composition can be enhanced, improving heat resistance and making it easier to control mechanical properties. Examples of surface treatment of the filler include coupling agent treatment. Preferred functional groups introduced through surface treatment include vinyl groups, acrylic groups, methacrylic groups, amino groups, epoxy groups, and mercapto groups. Radical polymerizable functional groups present on the surface of a filler refer to functional groups in which the active species induces the polymerization of radicals (called radical polymerization). This is broadly interpreted to include, for example, 1,2-disubstituted double bond groups such as (meth)acryloyl groups, vinyl groups, and maleimide, as well as diene skeletons. Radical polymerizable functional groups chemically bond the filler having them on its surface to the thermosetting resin composition of the first curable resin layer 10 through the curing reaction, thereby improving the chemical resistance of the interface. Furthermore, fillers having radical polymerizable functional groups on their surface have a more appropriate polarity than fillers in which other functional groups are introduced by surface treatment, thus improving dispersibility in resins and solvents, and enabling effective improvement of chemical resistance and control of mechanical properties. From the viewpoint of easily improving chemical resistance and controlling mechanical properties with a small amount of compounding, inorganic fillers having radical polymerizable functional groups on their surface are preferred as fillers having radical polymerizable functional groups on their surface, and silica having radical polymerizable functional groups on its surface is more preferred from the viewpoint of easy coupling agent treatment and uniform surface treatment.

[0050] When attaching radically polymerizable functional groups to the surface of an inorganic filler, one example is to immerse the inorganic filler in a liquid containing a radically polymerizable compound. Examples of compounds having radically polymerizable functional groups (radically polymerizable compounds) include monofunctional radically polymerizable compounds such as acrylamide compounds, (meth)acrylate compounds, maleimide compounds, styrene compounds, acrylonitrile compounds, vinyl ester compounds, N-vinyl compounds, conjugated diene compounds, vinyl ketone compounds, and halogenated vinyl / vinylidene halogenated compounds; and one or more polyfunctional radically polymerizable compounds such as (meth)acrylate compounds, vinyl ether group-containing (meth)acrylate compounds, (meth)acryloyl group-containing isocyanurate compounds, (meth)acrylamide compounds, urethane (meth)acrylate compounds, maleimide compounds, vinyl ether compounds, and aromatic vinyl compounds. The radically polymerizable compound preferably contains a coupling agent, such as a silane coupling agent. More preferably, surface treatments for inorganic fillers include coupling agent treatment.

[0051] The particle size of the inorganic filler is preferably 100 μm or less, more preferably 10 to 500 nm, even more preferably 10 to 300 nm, and most preferably 10 to 100 nm. In this application, particle size refers to the average particle size and can be determined by a dynamic light scattering measuring device. An example of a dynamic light scattering measuring device is the NanotracWave II UT151 manufactured by Microtrac-Bell. The amount of inorganic filler blended in the first curable resin layer 10 is preferably 70 to 300 parts by mass, more preferably 90 to 250 parts by mass, per 100 parts by mass of the total resin solids of the first curable resin layer 10. Examples of fillers having radical polymerizable functional groups on their surface include "YA050C-SM1", "K180SM-C1", "YA050C-SV6", and "3SM-C18" manufactured by Admatex Co., Ltd.

[0052] (Pigment) The first curable resin layer 10 is preferably colored and preferably contains a pigment for coloring. Preferably, carbon black, titanium oxide, iron oxide, etc., can be used as the pigment. More preferably, the first curable resin layer 10 is colored black and preferably contains a black pigment for coloring. More preferably, carbon black can be used as the black pigment. By including carbon black in the first curable resin layer 10, light shielding between the multiple light-emitting elements 21, 22, 23 of the element-equipped substrate 2 can be achieved. As the carbon black, one or more known carbon blacks such as gas black, channel black, furnace black, thermal black, and lamp black can be used. Resin-coated carbon black may also be used. Furthermore, carbon nanofibers and carbon nanotubes may be used.

[0053] Among the above options, gas black is preferred because it has a large amount of surface functional groups, high dispersibility, and exhibits sufficient light-shielding function with only a small amount added. Furthermore, when the second curing resin layer 11 contains a modified elastomer having functional groups that can react with epoxy resin, the interaction between the surface functional groups of gas black and the functional groups of the modified elastomer having functional groups that can react with epoxy resin further enhances dispersibility, ensuring good light-shielding properties and coating stability.

[0054] The particle size of the black pigment, such as carbon black, is preferably 100 μm or less, more preferably 10 to 500 nm, even more preferably 10 to 300 nm, and most preferably 10 to 100 nm. The amount of the black pigment, such as carbon black, blended is preferably 0.1 to 15 parts by mass, and more preferably 1.0 to 12 parts by mass, per 100 parts by mass of the total resin solids of the first curable resin layer 10. If the blending amount is above the lower limit, sufficient light shielding properties can be obtained. If the blending amount is below the upper limit, the thixotropy of the first curable resin layer 10 is suppressed, the fluidity during thermocompression bonding is improved, and the spaces between the multiple light-emitting elements 21, 22, and 23 of the element-equipped substrate 2 can be sufficiently filled.

[0055] (Other ingredients) The first curable resin layer 10 may further contain, if necessary, resins other than epoxy resin and elastomer, thickeners, defoamers and / or leveling agents, coupling agents and other adhesion modifiers, flame retardants, and refractive index modifiers.

[0056] (2) Second curable resin layer The second curable resin layer 11 is a layer that sufficiently presses the first curable resin layer 10 between the multiple light-emitting elements 21, 22, and 23 arranged on the substrate 2 with the elements during the pressing and filling processes described later. In addition, it prevents appearance defects such as air bubbles and repulsion during the curing process, making it less likely to cause problems when etching is performed in a subsequent process. After curing, a wiring pattern made of metal is further formed on the second curable resin layer 11.

[0057] [Storage modulus] The storage modulus of the second curable resin layer 11 is different from that of the first curable resin layer 10. The storage modulus of the second curable resin layer 11 may be greater than or less than that of the first curable resin layer 10, but is preferably greater than that of the first curable resin layer 10, and more preferably greater than that of the first curable resin layer 10 at 100°C and 150°C.

[0058] Furthermore, if the storage modulus of the second curable resin layer 11 is greater than the storage modulus of the first curable resin layer 10 at 100°C and 150°C, then typically, the storage modulus of the second curable resin layer 11 is greater than the storage modulus of the first curable resin layer 10 across the entire temperature range from 100°C to 150°C.

[0059] If the storage modulus of the second curable resin layer 11 is smaller than that of the first curable resin layer 10, then in the subsequent pressing and filling process, the first curable resin layer 10 provides support as described above, making it less likely for irregularities to occur due to deformation of the second curable resin layer 11, and thus improving the smoothness after curing.

[0060] If the storage modulus of the second curable resin layer 11 is greater than that of the first curable resin layer 10, the second curable resin layer 11 can sufficiently press the first curable resin layer 10 between the multiple light-emitting elements 21, 22, and 23 during the pressing and filling process described later.

[0061] The storage modulus of the second curable resin layer 11 at 100°C is preferably 1.0 × 10⁻⁶ 7 It is less than or equal to Pa, and more preferably 1.0 × 10⁻⁶ 4 Pa~1.0×10 7 Pa is, and more preferably 5.0 × 10 4 Pa~5.0×10 6 It is Pa.

[0062] By having a storage modulus of elasticity at 100°C within a preferred range, the first curable resin layer 10 can be sufficiently pressed into the substrate 2 with the elements, and the fluidity of the second curable resin layer 11 itself can be maintained. Specifically, if the storage modulus of elasticity at 100°C of the second curable resin layer 11 is below a preferred upper limit, the fluidity of the second curable resin layer 11 will be sufficient. In addition, the occurrence of cracks in the second curable resin layer 11 during thermocompression bonding will be suppressed, and crack-like defects will be less likely to occur. On the other hand, if the storage modulus of elasticity at 100°C of the second curable resin layer 11 is above a preferred lower limit, the second curable resin layer 11 can achieve sufficient hardness to press the first curable resin layer 10 toward the light-emitting elements 21, 22, and 23 during thermocompression bonding. In addition, when the protective sheet 13 is peeled off after thermocompression bonding, it is possible to prevent appearance defects such as the surface of the second curable resin layer 11 becoming uneven in accordance with the light-emitting elements 21, 22, and 23. In addition, surface defects such as repellency are less likely to occur during heat curing.

[0063] The storage modulus of the second curable resin layer 11 at 150°C is preferably 1.0 × 10⁻⁶. 7 It is less than or equal to Pa, and more preferably 1.0 × 10⁻⁶ 4 Pa~1.0×10 7 It is less than or equal to Pa, and more preferably 1.0 × 10⁻⁶ 5 Pa~1.0×10 7Pa is particularly preferred, and 1.0 × 10 5 It is Pa or higher.

[0064] By having a storage modulus of elasticity of the second curable resin layer 11 at 150°C that is below a preferred upper limit, cracks due to curing shrinkage during thermal curing are less likely to occur. By having a storage modulus of elasticity of the second curable resin layer 11 at 150°C that is above a preferred lower limit, flow during thermal curing can be suppressed, and post-curing appearance defects such as repelling phenomena are suppressed. Furthermore, problems are less likely to occur when etching is performed in a subsequent process.

[0065] The storage modulus of the second curable resin layer 11 at 100°C is preferably 10 to 1000 times, and more preferably 30 to 500 times, the storage modulus of the first curable resin layer 10. The storage modulus of the second curable resin layer 11 at 150°C is preferably 3 to 10000 times, and more preferably 10 to 1000 times, the storage modulus of the first curable resin layer 10.

[0066] [Coefficient of linear expansion] The second curable resin layer 11 is a layer in which, after curing, the coefficient of linear expansion is preferably in the range of 90 ppm / K or less (for example, 0.1 ppm / K to 90 ppm / K), more preferably 75 ppm / K or less (for example, 1.5 ppm / K to 75 ppm / K), and even more preferably 50 ppm / K or less (for example, 2 ppm / K to 50 ppm / K). The coefficient of linear expansion of the second curable resin layer 11 after curing is preferably smaller than the coefficient of linear expansion of the first curable resin layer 10 after curing. By making the coefficient of linear expansion of the second curable resin layer 11 after curing as small as possible, the difference in thermal expansion coefficient between the metal wiring pattern and the cured layer of the second curable resin layer 11 can be reduced after curing the dry film 1. As a result, it becomes easier to reduce the occurrence of problems such as peeling of the wiring pattern or cracking of the wiring pattern in processes after wiring patterning and reliability tests.

[0067] In other words, the coefficient of linear expansion of the first curable resin layer 10 after curing is preferably greater than the coefficient of linear expansion of the second curable resin layer 11 after curing. Increasing the coefficient of linear expansion of the first curable resin layer 10 after curing reduces the melt viscosity of the dry film 1 during thermocompression bonding, thereby making it easier to fill the spaces between the light-emitting elements 21, 22, and 23.

[0068] By making the coefficient of linear expansion of the second curable resin layer 11 after curing smaller than that of the first curable resin layer 10 after curing, problems such as delamination of the wiring pattern or cracking of the wiring pattern can be reduced. Furthermore, the melt viscosity of the dry film 1 during thermocompression bonding, more specifically the melt viscosity of the first curable resin layer 10, can be reduced, making it easier to fill the spaces between the light-emitting elements 21, 22, and 23 with the dry film 1. The coefficients of linear expansion of these laminated layers 10 and 11 can be controlled by the amount of inorganic filler contained in each layer 10 and 11 (also known as the blending amount or content), the introduction of rigid and crystalline structures into the thermosetting resin composition, and the adjustment of the crosslinking density. Specifically, by making the inorganic filler content in the second curable resin layer 11 equal to or greater than the inorganic filler content in the first curable resin layer 10, the above control of the coefficient of linear expansion can be easily achieved. In addition to the inorganic filler content, the type of curable resin used in the second curable resin layer 11 and the first curable resin layer 10 may also be changed to reduce the coefficient of thermal expansion of the cured layer of the second curable resin layer 11 after curing.

[0069] [Thermosetting resin composition] The second curable resin layer 11 is preferably composed of a thermosetting resin composition. Examples of thermosetting resin compositions include those similar to those used for the first curable resin layer 10. Among these, an epoxy resin composition is preferred because it enables thermosetting at low temperatures and exhibits excellent heat resistance and reliability.

[0070] (Epoxy resin) Examples of epoxy resins used in the second curable resin layer 11 include those of the same type as those used in the first curable resin layer 10. From the viewpoint of imparting an appropriate viscosity to the second curable resin layer 11 during bonding, it is preferable that the second curable resin layer 11 contains a high molecular weight epoxy resin.

[0071] The weight-average molecular weight of the high molecular weight epoxy resin contained in the second curable resin layer 11 is preferably 10,000 to 100,000. This allows the second curable resin layer 11 to have an appropriate viscosity during compression, enabling the first curable resin layer 10 to be sufficiently pressed in during thermal compression bonding. Furthermore, it suppresses flow during thermal curing, reduces post-curing appearance defects such as repulsion, and minimizes interference when etching is performed in a subsequent process.

[0072] It is more preferable to include an epoxy resin with a weight-average molecular weight of 10,000 to 35,000, from the viewpoint of good compatibility with other resin components and the ability to dissolve without mixing in high-boiling-point solvents that may remain in the dry film 1 after drying.

[0073] By including a high molecular weight epoxy resin with a weight-average molecular weight of 10,000 to 100,000 as the epoxy resin used in the second curable resin layer 11, it has an appropriate viscosity when heated, allowing the storage modulus of the second curable resin layer 11 in the 100°C to 150°C range to be adjusted to a desirable range.

[0074] The high molecular weight epoxy resin used in the second curing resin layer 11 is preferably a phenoxy resin because of its good compatibility with other epoxy resins.

[0075] Phenoxy resin has a relatively large molecular weight among epoxy resins and possesses a suitable viscosity when heated, allowing the storage modulus of the second curable resin layer 11 in the 100°C to 150°C range to be adjusted to a desirable range. Furthermore, unlike other thermoplastic resins such as polyester, phenoxy resin can be cured as an epoxy resin, allowing for increased crosslinking density and ensuring the reliability of the cured product's heat resistance and long-term performance.

[0076] From the viewpoint of ensuring a storage modulus that allows the first curable resin layer 10 to be pressed in during thermocompression bonding, it is preferable that the glass transition temperature of the phenoxy resin used in the second curable resin layer 11 be 100°C or higher.

[0077] Specific examples of phenoxy resins include, for example, "YX7200," "1256," "YX8100," and "YX7180" from Mitsubishi Chemical Corporation, "YP-50," "YP-50S," and "YP-70" from Nippon Steel Chemical & Material Corporation, and "N-690," "H-157," and "EXA-192" from DIC Corporation.

[0078] The amount of high molecular weight epoxy resin blended in the second curable resin layer 11 is preferably 10 to 80 parts by mass, more preferably 15 to 65 parts by mass, and even more preferably 20 to 50 parts by mass, based on 100 parts by mass of the total resin solids content of the second curable resin layer 11.

[0079] When the high molecular weight epoxy resin is within the above blending range, the storage modulus can be controlled, ensuring a storage modulus suitable for pressing the first curable resin layer 10 during thermal bonding. Furthermore, flow during thermal curing can be suppressed, preventing post-curing appearance defects such as repulsion, and minimizing problems when etching is performed in subsequent processes. In addition, toughness is improved, making it less likely for crack-like defects to occur during thermal bonding. Moreover, when the high molecular weight epoxy resin is below the above upper limit, the crosslinking density of the cured product of the second curable resin layer 11 can be increased, improving heat resistance and chemical resistance.

[0080] Furthermore, it is preferable that the epoxy resin used in the second curable resin layer 11 includes a polyfunctional epoxy resin.

[0081] By increasing the crosslinking density, the polyfunctional epoxy resin further improves the stability of the cured epoxy resin composition's performance over long-term use, and also improves its heat resistance and coefficient of thermal expansion. Furthermore, because it has a lower viscosity in the 100°C to 150°C range than phenoxy resin, combining it with phenoxy resin allows for adjustment of the storage modulus of the second curable resin layer 11.

[0082] Specific examples of polyfunctional epoxy resins include, for example, "YX7700," "157S70," and "1032S60" from Mitsubishi Chemical Corporation, "NC7000L," "XD1000," and "EOCN-1020" from Nippon Kayaku Co., Ltd., "ESN485" from Nippon Steel Chemical & Material Co., Ltd., and "N-690," "N-695," and "HP-7200H" from DIC Corporation.

[0083] The amount of polyfunctional epoxy resin in the second curable resin layer 11 is preferably 90 parts by mass or less, and more preferably 10 to 70 parts by mass, based on 100 parts by mass of the total resin solids content of the second curable resin layer 11. If the amount of polyfunctional epoxy resin is within the above range, the storage modulus of the second curable resin layer 11 during thermocompression bonding can be controlled, and heat resistance and chemical resistance can be imparted to the cured product. Furthermore, by increasing the crosslinking density, the coefficient of linear expansion of the second curable resin layer 11 after curing can be increased.

[0084] From the viewpoint of ensuring sufficient fluidity during thermocompression bonding, it is preferable that the second curable resin layer 11 contains an epoxy resin with a softening point or melting point of 120°C or lower. From the viewpoint of handling properties and heat resistance of the cured product, it is more preferable that it contains an epoxy resin with a softening point or melting point of 50 to 105°C. By including an epoxy resin having a softening point or melting point within the above range, it becomes possible to control the storage modulus.

[0085] The total amount of epoxy resin in the second curable resin layer 11 is preferably 10 to 100 parts by mass, more preferably 30 to 99 parts by mass, and even more preferably 50 to 98 parts by mass, based on 100 parts by mass of the total resin solids content of the second curable resin layer 11. When the total amount of epoxy resin is within the above range, the storage modulus can be controlled, and a storage modulus suitable for pressing the first curable resin layer 10 during thermal bonding can be ensured. Furthermore, flow during thermal curing can be suppressed, post-curing appearance defects such as repulsion can be suppressed, and problems are less likely to occur when etching is performed in a subsequent process. In addition, when the total amount of epoxy resin is above the above lower limit, the heat resistance after curing can be improved.

[0086] (Elastomer) The second curable resin layer 11 preferably contains an elastomer in addition to a resin such as epoxy resin. Including an elastomer makes it easier to control the storage modulus. Furthermore, it can impart flexibility to the second curable resin layer 11.

[0087] Examples of elastomers include those of the same type as the first curable resin layer 10. Among the various elastomers, NBR is preferred because it has good compatibility with epoxy resin, can increase the storage modulus of the second curable resin layer 11 at around 150°C, and has good adhesion to the first curable resin layer 10. The preferred weight-average molecular weight of the elastomer is also the same as that of the first curable resin layer 10.

[0088] In particular, when the second curable resin layer 11 is composed of an epoxy resin composition, it preferably contains a modified elastomer having a functional group that can react with epoxy groups, and more preferably contains NBR. If the modified elastomer has a functional group that can react with epoxy groups, it also acts as a curing agent for the epoxy resin. Furthermore, because it can react and bond with the epoxy resin, its heat resistance and reliability against thermal shock are improved. In addition, the difference in polarity between the functional group that can react with the epoxy resin and the resin skeleton has a good effect on dispersibility, and good dispersibility can be obtained when the second curable resin layer 11 contains fillers or carbon black.

[0089] Functional groups that can react with epoxy groups include those of the same type as those used in the first curable resin layer 10. Among these, acid groups or acid anhydride groups are preferred, and carboxyl groups or carboxylic acid anhydride groups are particularly preferred, as they allow curing at low temperatures and ensure a long pot life.

[0090] When the second curable resin layer 11 is composed of an epoxy resin composition, it is particularly preferable that it contains modified NBR having a carboxyl group. Examples of modified NBR having a carboxyl group include those of the same type as those used in the first curable resin layer 10. Two or more modified elastomers having functional groups that can react with epoxy groups may be used in combination.

[0091] In other words, when the second curable resin layer 11 is composed of an epoxy resin composition, it preferably contains an acid-modified elastomer having acid groups or acid anhydride groups, more preferably an acid-modified elastomer having carboxyl groups, and even more preferably modified NBR having carboxyl groups. By including modified NBR having carboxyl groups in the second curable resin layer 11, adhesion to wiring patterns made of metal can be improved.

[0092] The amount of elastomer in the second curable resin layer 11 is preferably less than the amount of elastomer in the first curable resin layer 10, preferably 0 to 70 parts by mass, and more preferably 0.1 to 30 parts by mass, per 100 parts by mass of the total resin solids content of the second curable resin layer 11. When the amount of elastomer is within the above range, the storage modulus can be controlled. Furthermore, when the amount of elastomer is below the above upper limit, the storage modulus that can press the first curable resin layer 10 during thermal bonding can be ensured. In addition, flow during thermal curing can be suppressed, post-curing appearance defects such as repulsion can be suppressed, and furthermore, problems are less likely to occur when etching is performed in a subsequent process. In addition, the coefficient of linear expansion of the second curable resin layer 11 after curing can be increased. Furthermore, when the amount of elastomer is above the above lower limit, dispersibility is improved when fillers or carbon black are included. Furthermore, film-forming properties are improved, and the film thickness distribution when coating and forming an epoxy resin composition can be narrowed. In addition, flexibility can be imparted to the second curable resin layer 11.

[0093] (Hardening agent) If the second curable resin layer 11 is composed of an epoxy resin composition, it may contain other curing agents for epoxy resins other than modified elastomers having functional groups that can react with epoxy groups. Examples of other curing agents include those similar to those used in the first curable resin layer 10. Two or more other curing agents may be used in combination.

[0094] (curing catalyst) If the second curable resin layer 11 is composed of an epoxy resin composition, it may contain a curing catalyst that promotes the curing reaction of the epoxy resin. Examples of curing catalysts include those similar to those used in the first curable resin layer 10, and preferred embodiments are also similar.

[0095] The amount of curing catalyst added is preferably 0.001 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the total resin solids content of the second curable resin layer 11. When the amount of curing catalyst is within the above range, curing can proceed sufficiently, and the pot life of the dry film 1 can be ensured. Two or more types of curing catalysts may be used in combination.

[0096] (Polymerization initiator) The second curable resin layer 11 contains a polymerization initiator. The polymerization initiator has the function of creating a chemical bond between the radical polymerizable functional group and the resin component of the second curable resin layer. The polymerization initiator is preferably a radical polymerization initiator, but may also be a cationic polymerization initiator that generates radicals. If it also acts as a curing catalyst for the epoxy resin composition, such as a cationic polymerization initiator, it is used as a polymerization initiator. The preferred type and preferred amount of polymerization initiator are the same as in the case of the first curable resin layer 10.

[0097] (Filler) The second curable resin layer 11 preferably contains a filler (excluding the pigment described later) as long as it does not hinder sufficient filling of the spaces between the multiple light-emitting elements 21, 22, and 23 of the element-equipped substrate 2. In this embodiment, the second curable resin layer 11 contains a filler having radically polymerizable functional groups on its surface. The filler is preferably an inorganic filler. However, an organic material-based filler may also be used as the filler. There are no particular restrictions on the filler, but preferred examples include inorganic fillers such as silica, talc, mica, alumina, and boron nitride. Examples of silica include fumed silica and colloidal silica.

[0098] The filler is preferably surface-treated. Surface treatment of the filler improves its dispersibility and makes it easier to control its mechanical properties. Furthermore, by introducing functional groups that can react with epoxy resin or functional groups that can undergo radical polymerization through surface treatment, the interaction at the interface between the filler and the thermosetting resin composition can be enhanced, improving heat resistance and making it easier to control mechanical properties. Examples of surface treatments for the filler include coupling agent treatment. Preferred functional groups introduced through surface treatment include vinyl groups, acrylic groups, methacrylic groups, amino groups, epoxy groups, and mercapto groups. Radical polymerizable functional groups present on the surface of the filler refer to functional groups in which the active species causes radical polymerization (called radical polymerization), and are broadly interpreted to include, for example, 1,2-disubstituted double bond groups such as (meth)acryloyl groups, vinyl groups, and maleimide, as well as diene skeletons. Radical polymerizable functional groups can chemically bond the filler having them on its surface to the thermosetting resin composition of the second curable resin layer 11 through the curing reaction, thereby improving the chemical resistance of the interface. Furthermore, fillers having radically polymerizable functional groups on their surface have a more appropriate polarity than fillers in which other functional groups are introduced by surface treatment, thus improving dispersibility in resins and solvents and enabling effective improvement of chemical resistance and control of mechanical properties. From the viewpoint of easily improving chemical resistance and controlling mechanical properties with a small amount of compounding, inorganic fillers having radically polymerizable functional groups on their surface are preferred as fillers having radically polymerizable functional groups on their surface, and from the viewpoint of easy coupling agent treatment and uniform surface treatment, silica having radically polymerizable functional groups on its surface is more preferred.

[0099] The method for attaching radically polymerizable functional groups to the surface of the inorganic filler and the preferred particle size of the inorganic filler are the same as in the case of the first curable resin layer 10. The filler content in the second curable resin layer 11 is preferably equal to or greater than the filler content in the first curable resin layer 10. The amount of filler blended in the second curable resin layer 11 is preferably 80 to 400 parts by mass, more preferably 100 to 350 parts by mass, per 100 parts by mass of the total resin solids content of the second curable resin layer 11.

[0100] (Pigment) The second curable resin layer 11 is preferably colored and, for coloring purposes, preferably contains a pigment. The pigment is the same as in the case of the first curable resin layer 10.

[0101] (Other ingredients) The second curable resin layer 11 may further contain, if necessary, resins other than epoxy resin and elastomer, thickeners, defoamers and / or leveling agents, coupling agents and other adhesion modifiers, flame retardants, and refractive index modifiers.

[0102] (3) Protective sheet The protective sheets 12 and 13 serve to protect at least the first curable resin layer 10 and the second curable resin layer 11 of the dry film 1. The protective sheets 12 and 13 can also be used as sheets to which the coating liquid of the curable resin composition is applied when forming the dry film 1.

[0103] As protective sheets 12 and 13, for example, sheets made of polyester such as polyethylene terephthalate or polyethylene naphthalate, thermoplastic resins such as polyimide, polyamide-imide, polyethylene, polytetrafluoroethylene, polypropylene, or polystyrene, or surface-treated paper can be used.

[0104] Among these options, polyester sheets are preferable from the viewpoint of heat resistance, mechanical strength, and ease of handling. The thickness of the protective sheets 12 and 13 is not particularly limited and can be appropriately selected in the range of approximately 10 to 150 μm depending on the application. The surfaces of the protective sheets 12 and 13 on which the first curable resin layer 10 and the second curable resin layer 11 are provided may be treated with a release agent.

[0105] (4) Form of a single curable resin layer Earlier, a dry film 1 comprising a curable resin layer 9 containing a first curable resin layer 10 and a second curable resin layer 11 was described. However, the dry film 1 may also consist of only the first curable resin layer 10 or only the second curable resin layer 11 as the curable resin layer 9. The radical polymerizable functional groups are preferably attached to the particle surface of some or all of the inorganic filler (for example, some or all of the silica). The previously exemplified materials can be suitably used as polymerization initiators. The polymerization initiator has the function of creating a chemical bond between the radical polymerizable functional groups and the curable resin composition of the curable resin layer 9. The polymerization initiator may also be a cationic polymerization initiator that generates radicals during cationic polymerization. The amount of polymerization initiator blended is preferably 0.001 to 5 parts by mass per 100 parts by mass of the total resin solids content of the curable resin layer 9.

[0106] 2. Method for manufacturing dry film To obtain the dry film 1, first, a protective sheet 12 is coated with a coating solution of the curable resin composition for the first curable resin layer 10 and dried, and a protective sheet 13 is coated with a coating solution of the curable resin composition for the second curable resin layer 11 and dried. The coating solutions for the first curable resin layer 10 and / or the second curable resin layer 11 contain a filler with radically polymerizable functional groups attached to its surface. To manufacture such a filler, the untreated filler and a material containing radically polymerizable functional groups are mixed in a solvent or dispersion medium and stirred, and then dried to coat the surface of the untreated filler with the material. As a result, a filler with radically polymerizable functional groups attached to its surface can be obtained. Materials containing radically polymerizable functional groups include monofunctional radical polymerizable compounds such as acrylamide compounds, (meth)acrylate compounds, maleimide compounds, styrene compounds, acrylonitrile compounds, vinyl ester compounds, N-vinyl compounds, conjugated diene compounds, vinyl ketone compounds, and halogenated vinyl / vinylidene halogenated compounds; and polyfunctional radical polymerizable compounds such as (meth)acrylate compounds, vinyl ether group-containing (meth)acrylate compounds, (meth)acryloyl group-containing isocyanurate compounds, (meth)acrylamide compounds, urethane (meth)acrylate compounds, maleimide compounds, vinyl ether compounds, and aromatic vinyl compounds.

[0107] Subsequently, these are stacked so that the second curable resin layer 11 and the first curable resin layer 10 are in contact, and laminated to obtain a dry film 1 in which the protective sheet 12, the first curable resin layer 10, the second curable resin layer 11, and the protective sheet 13 are sequentially laminated. When manufacturing a dry film 1 having only one curable resin layer 9, the protective sheet 13 can be coated with a coating solution of the curable resin composition for the first curable resin layer 10 or the second curable resin layer 11 and then dried.

[0108] The coating liquid of the curable resin composition for the first curable resin layer 10 and the second curable resin layer 11 preferably contains an amount of organic solvent that results in a viscosity that allows for application without hindrance. There are no particular limitations on the organic solvent, but examples include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum-based solvents. Specifically, these include ketones such as methyl ethyl ketone, cyclohexanone, methyl butyl ketone, and methyl isobutyl ketone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; and ethyl acetate, butyl acetate, isobutyl acetate, and ethyl acetate. Examples of carbon black include esters such as propylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, and propylene glycol butyl ether acetate; alcohols such as ethanol, propanol, 2-methoxypropanol, n-butanol, isobutyl alcohol, isopentyl alcohol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha; and N,N-dimethylformamide (DMF), tetrachloroethylene, and turpentine oil. When incorporating carbon black into a coating solution, carbon black powder may be added to the coating solution, or a pre-dispersed carbon black solution (carbon black dispersion) may be added.

[0109] Methods for applying the above-mentioned curable resin composition include, for example, using various coaters such as die coaters, gravure coaters, roll coaters, curtain flow coaters, spin coaters, bar coaters, reverse coaters, kiss coaters, fountain coaters, rod coaters, air doctor coaters, knife coaters, blade coaters, cast coaters, and screen coaters. The drying temperature is preferably 60 to 160°C, more preferably 80 to 130°C, and even more preferably 90 to 120°C.

[0110] The lamination temperature is preferably 20 to 120°C, more preferably 30 to 100°C, and even more preferably 40 to 80°C. By setting the temperature above the preferred lower limit, sufficient adhesion between the first curable resin layer 10 and the second curable resin layer 11 can be ensured, allowing for handling even before curing. Furthermore, by setting the temperature below the preferred upper limit, the trapping of air bubbles between the first curable resin layer 10 and the second curable resin layer 11, and the formation of wrinkles on each layer 10 and 11 can be prevented. Lamination can be carried out using, for example, a roll laminator, a press, a vacuum press, etc.

[0111] 3. Circuit board with components As shown in Figure 2, the element-equipped substrate 2 has multiple light-emitting elements 21, 22, and 23 arranged on a substrate 20. In Figure 2, etc., a schematic representation shows a portion where three light-emitting elements (light-emitting element 21, light-emitting element 22, and light-emitting element 23) are arranged. The number of light-emitting elements 21, 22, and 23 provided on the element-equipped substrate 2 is not particularly limited as long as there are multiple elements, but three are preferred. The light-emitting electronic component 5 manufactured by the manufacturing method according to this embodiment includes three light-emitting elements 21, 22, and 23. Although three light-emitting elements 21, 22, and 23 are shown in Figure 2, etc., there may be two or four or more. The term light-emitting electronic component can be broadly interpreted to include light-emitting element packages that package minute light-emitting elements such as MIP elements.

[0112] The light-emitting elements 21, 22, and 23 are fixed to the substrate 20 on the side with the light-emitting surface 24. The method of fixing the light-emitting elements 21, 22, and 23 is not particularly limited, and for example, the light-emitting elements 21, 22, and 23 may be formed on the substrate 20 from a crystalline layer such as gallium nitride (GaN). When forming the light-emitting elements 21, 22, and 23 on the substrate 20, it is preferable to epitaxially grow a crystalline layer such as GaN on the substrate 20, process it to a desired size and shape, and form electrodes 25, etc., on the top. Alternatively, a layer to which the light-emitting surface 24 can be bonded may be provided on the substrate 20 and bonded. In this case, any known material may be used for the layer, for example, polyimide, benzocyclobutene, silicone resin, etc. Among these, the use of silicone resin is preferred.

[0113] Each light-emitting element 21, 22, and 23 is equipped with an electrode 25 on the side opposite to the light-emitting surface 24 fixed on the substrate 20. In Figure 2 and other figures, two electrodes 25 are shown for each light-emitting element.

[0114] The light-emitting elements 21, 22, and 23 are typically light-emitting diodes (LEDs). This embodiment is particularly suitable when the light-emitting elements 21, 22, and 23 are extremely small. For example, LEDs with a height of 1000 nm to 200 μm and a side length of 0.001 to 0.5 mm can be used. The light-emitting color of the light-emitting elements 21, 22, and 23 is not particularly limited, but is preferably red, green, and blue. It is also possible to use blue LEDs for all of the light-emitting elements 21, 22, and 23.

[0115] The material of the substrate 20 is not particularly limited as long as it does not obstruct the reach of light to the viewer. When the light-emitting elements 21, 22, and 23 are formed on the substrate 20, known substrates for forming light-emitting elements can be suitably used, and sapphire glass substrates are preferred.

[0116] 4. Light-emitting electronic component and method for manufacturing the same The following describes an example using a dry film 1 comprising a first curable resin layer 10 and a second curable resin layer 11. The light-emitting electronic component 5 comprises an element-equipped substrate 2 in which the light-emitting surfaces 24 side of a plurality of light-emitting elements 21, 22, 23 are fixed to a substrate 20, and a cured dry film ("cured dry film," "cured dry film body," or simply "cured product") 3 which is a film after curing the first curable resin layer 10 and the second curable resin layer 11 of any of the dry films 1 described above, and is pressed onto the side of the element-equipped substrate 2 on which the plurality of light-emitting elements 21, 22, 23 are arranged.

[0117] As shown in Figure 6, the cured dry film 3 has a structure in which a first resin layer 30 and a second resin layer 31 are laminated in that order from the side of the element-equipped substrate 2 closest to the substrate 20. The first resin layer 30 is the resin layer after curing of the first curable resin layer 10. The second resin layer 31 is the resin layer after curing of the second curable resin layer 11.

[0118] The first resin layer 30 is laminated on the substrate 20 and fills the spaces between the multiple light-emitting elements 21, 22, and 23.

[0119] The second resin layer 31 is laminated on the side of the first resin layer 30 opposite to the substrate 20. The second resin layer 31 covers at least a portion of the plurality of light-emitting elements 21, 22, 23, and preferably exposes at least a portion of the electrodes 25 in the light-emitting elements 21, 22, 23.

[0120] The manufacturing method for the light-emitting electronic component 5 according to this embodiment includes the steps of: pressing the dry film 1 against the side of the element-equipped substrate 2 on which the plurality of light-emitting elements 21, 22, 23 are arranged, so that the first curable resin layer 10 of one of the dry films 1 described above is in contact with the electrodes 25 of the plurality of light-emitting elements 21, 22, 23 (hereinafter referred to as the pressing step); filling the spaces between the plurality of light-emitting elements 21, 22, 23 with the first curable resin layer 10 and the second curable resin 11 (hereinafter referred to as the filling step); and curing the first curable resin layer 10 and the second curable resin layer 11 (hereinafter referred to as the curing step). The manufacturing method for the light-emitting electronic component according to one embodiment (also simply referred to as the "manufacturing method") will be described below with reference to Figures 3 to 6.

[0121] (i) Crimping process In the manufacturing method of this embodiment, first, the protective sheet 12 is peeled off to expose the first curable resin layer 10, and as shown in Figure 3, the dry film 1 is pressed against the surface of the element-equipped substrate 2 on which the light-emitting elements 21, 22, and 23 are arranged, and the pressing of the dry film 1 is started.

[0122] At this time, that is, before crimping, the thickness of the first curable resin layer 10 is preferably 15 to 95% of the height of the light-emitting elements 21, 22, and 23. The lower limit is more preferably 20% or more, and even more preferably 30% or more. The upper limit is more preferably 90% or less, and even more preferably 80% or less.

[0123] In this specification and in the claims, “height of the light-emitting element” means the height from the light-emitting surface 24 fixed to the substrate 20 of the light-emitting elements 21, 22, and 23 to the tip surface of the electrode 25.

[0124] If the thickness of the first curable resin layer 10 is 15% or more of the height of the light-emitting elements 21, 22, and 23, the resin can be sufficiently filled between the light-emitting elements 21, 22, and 23. If the thickness of the first curable resin layer 10 is 20% or more of the height of the light-emitting elements 21, 22, and 23, the fluidity of the second curable resin layer 11 will be sufficient, and crack-like defects will not occur on the surface. If the thickness of the first curable resin layer 10 is 30% or more of the height of the light-emitting elements 21, 22, and 23, the fluidity of the first curable resin layer 10 can be utilized to appropriately fill the dry film 1 between the light-emitting elements 21, 22, and 23.

[0125] If the thickness of the first curable resin layer 10 is 95% or less of the height of the light-emitting elements 21, 22, and 23, leakage of the first curable resin layer 10 to the outside during thermocompression bonding can be prevented, and the film thickness can be ensured. If the thickness of the first curable resin layer 10 is 90% or less of the height of the light-emitting elements 21, 22, and 23, the flow of the first curable resin layer 10 after pressing is prevented, suppressing variations in film thickness and preventing variations in black color. If the thickness of the first curable resin layer 10 is 80% or less of the height of the light-emitting elements 21, 22, and 23, the fluidity of the first curable resin layer 10 can be utilized to appropriately fill the space between the light-emitting elements 21, 22, and 23 with the dry film 1.

[0126] The thickness of the second curable resin layer 11 before compression is preferably 10 to 90% of the height of the light-emitting element. The lower limit is more preferably 15% or more, and even more preferably 25% or more. The upper limit is more preferably 75% or less, and even more preferably 60% or less.

[0127] If the thickness of the second curable resin layer 11 is 10% or more of the height of the light-emitting element, it can be prevented from flowing together with the first curable resin layer 10 during thermal curing, thereby preventing surface defects. If the thickness of the second curable resin layer 11 is 15% or more of the height of the light-emitting element, there is a sufficient range for the flow of the second curable resin layer 11, preventing the occurrence of crack-like defects on the surface. If the thickness of the second curable resin layer 11 is 25% or more of the height of the light-emitting element, the first curable resin layer 10 can be sufficiently pressed in.

[0128] If the thickness of the second curing resin layer 11 is less than or equal to the above upper limit relative to the height of the light-emitting element, the subsequent etching process can be shortened.

[0129] The combined thickness of the first curable resin layer 10 and the second curable resin layer 11 before bonding is preferably 70-300% of the height of the light-emitting elements 21, 22, and 23, more preferably 80-200%, and even more preferably 90-160%. If the combined thickness of the first curable resin layer 10 and the second curable resin layer 11 is greater than or equal to the lower limit of the height of the light-emitting elements 21, 22, and 23, the dry film 1 can be sufficiently embedded between the light-emitting elements 21, 22, and 23. If the combined thickness of the first curable resin layer 10 and the second curable resin layer 11 is less than or equal to the upper limit of the height of the light-emitting elements 21, 22, and 23, the time for the subsequent etching process can be shortened or omitted.

[0130] The ratio of the thickness of the first curable resin layer 10 before pressing to the total thickness of the second curable resin layer 11 and the first curable resin layer 10 before pressing is preferably 30-90%, more preferably 35-80%, and even more preferably 40-70%.

[0131] If the ratio of the thickness of the first curable resin layer 10 before pressing to the total thickness of the second curable resin layer 11 and the first curable resin layer 10 is equal to or greater than the lower limit, the second curable resin layer 11 can sufficiently press the first curable resin layer 10, and the resin can be sufficiently filled between the light-emitting elements 21, 22, and 23. If the ratio is equal to or less than the upper limit, the second curable resin layer 11 will not flow during thermal pressing, suppressing flow during thermal curing, which suppresses defects in the appearance after curing such as repulsion, and furthermore, it is less likely to cause problems when etching is performed in a subsequent process.

[0132] (ii) Filling process Next, the pressing process is continued, embedding the dry film 1 until it reaches the substrate 20 of the element-equipped substrate 2. At this time, the first curable resin layer 10 and the second curable resin layer 11 are filled between the multiple light-emitting elements 21, 22, and 23. At the pressing temperature, the storage modulus of the second curable resin layer 11 is greater than that of the first curable resin layer 10. Therefore, the first curable resin layer 10, under pressure from the second curable resin layer 11, easily follows the irregularities caused by the light-emitting elements 21, 22, and 23 and is filled between the light-emitting elements 21, 22, and 23. At the pressing temperature, the storage modulus of the second curable resin layer 11 is not too large, so the second curable resin layer 11 is also filled between the light-emitting elements 21, 22, and 23.

[0133] The temperature during heat bonding is 80 to 120°C, preferably 90 to 110°C. Setting the temperature during heat bonding to 80°C or higher makes it easier to ensure the fluidity of the dry film 1. Setting the temperature during heat bonding to 120°C or lower makes it less likely to damage the light-emitting elements 21, 22, and 23. Setting the temperature during heat bonding to 90 to 110°C allows for more precise control of fluidity, suppressing the occurrence of unevenness and crack-like defects.

[0134] The pressure used in heat bonding is preferably 0.05 to 2.0 MPa, and more preferably 0.1 to 1.0 MPa. By setting the pressure used in heat bonding to be above the preferred lower limit, the dry film 1 can be filled between the light-emitting elements 21, 22, and 23. By setting the pressure to be below the preferred upper limit, damage to the light-emitting elements 21, 22, and 23 is minimized.

[0135] The heat-compression bonding is preferably performed using a vacuum press capable of molding under vacuum. This makes it easier to avoid defects caused by air being mixed into the resulting light-emitting electronic component 5.

[0136] (iii) Curing process After filling, as shown in Figure 5, the film is heat-cured to form the first curable resin layer 10 and the second curable resin layer 11 of the dry film 1 into the first resin layer 30 (cured layer of the first curable resin layer 10) and the second resin layer 31 (cured layer of the second curable resin layer 11). It is preferable to peel off the protective sheet 13 after curing.

[0137] The curing temperature is preferably 100 to 160°C, and more preferably 110 to 150°C. By setting the curing temperature to 100°C or higher, the first curable resin layer 10 and the second curable resin layer 11 of the dry film 1 can be reliably cured. By setting the curing temperature to 110°C or higher, the curing time of the first curable resin layer 10 and the second curable resin layer 11 can be shortened. Furthermore, by setting the curing temperature below the above upper limit temperature, damage to the light-emitting elements 21, 22, and 23 is less likely to occur.

[0138] The curing time depends on the curing temperature, but is preferably 30 to 360 minutes, and more preferably 45 to 180 minutes.

[0139] At the curing temperature, the second curable resin layer 11 has a relatively high storage modulus and suppressed fluidity, which reduces defects in appearance after curing and also minimizes problems when etching is performed in a subsequent process.

[0140] Subsequently, an etching process is preferably performed to remove the second resin layer 31 on the light-emitting elements 21, 22, and 23 to a height where at least a portion of the electrodes 25 of the light-emitting elements 21, 22, and 23 are exposed, as shown in Figure 6. By removing the second resin layer 31 to a height where at least a portion of the electrodes 25 are exposed, the light-emitting electronic components 5 can be mounted on a circuit board or the like via the electrodes 25 in a later process. Furthermore, if the thickness of the second resin layer 31 is thin and at least a portion of the electrodes 25 are already exposed after the curing process, the etching process can be omitted.

[0141] There are no limitations on the material of the circuit board, but known printed circuit boards can be suitably used. Examples of known printed circuit boards include epoxy glass substrates, fluororesin substrates, ceramic substrates, and glass substrates.

[0142] Etching can be either physical etching, such as plasma treatment, or chemical etching. For example, dry etching can be performed using an anisotropic plasma device with a mixed gas of CF4 / O2 / N2, at an output of 1500-3000W for 180-600 seconds. In this case, the gas supply rate of CF4 should be, for example, 50-100 sccm, the gas supply rate of O2 should be, for example, 500-1000 sccm, and the gas supply rate of N2 should be, for example, 50-100 sccm.

[0143] As described above, through the processes shown in Figures 3 to 6, a light-emitting electronic component 5 is obtained by pressing a dry film cured product 3 onto the surface of the element-equipped substrate 2, on which multiple light-emitting elements 21, 22, 23 are arranged, on which the light-emitting elements 21, 22, 23 are located. In the obtained light-emitting electronic component 5, the first curable resin layer 10 and the second curable resin layer 11 are cured to become the first resin layer 30 and the second resin layer 31. The first resin layer 30 is filled between the multiple light-emitting elements 21, 22, 23. In addition, at least a portion of the second resin layer 31 is filled between the multiple light-emitting elements 21, 22, 23.

[0144] The coefficient of linear expansion of the second resin layer 31 is smaller than that of the first resin layer 30. This reduces the occurrence of problems such as delamination of the wiring pattern or cracking of the wiring pattern. In addition, the first curable resin layer 10 does not have an excessively high melt viscosity when the dry film 1 is heat-compressed, making it easier to fill the space between the light-emitting elements 21, 22, and 23 with the dry film 1. Furthermore, at least the second resin layer 31 of the first resin layer 30 and the second resin layer 31 can achieve a strong bond between the resin layer and the filler through radical polymerizable functional groups within it. As a result, the electrode side of the cured dry film 3 becomes a layer with particularly high chemical resistance. [Examples]

[0145] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to these examples.

[0146] <Raw materials> The details of the raw materials used in each example and comparative example are as follows. [Epoxy resin] EOCN 1020-55: Cresol novolac type epoxy resin, manufactured by Nippon Kayaku Kogyo Co., Ltd., epoxy equivalent 194 g / eq. jER(registered trademark)1256: Manufactured by Mitsubishi Chemical Corporation, phenoxy type, bis-A type, epoxy equivalent 7158 g / eq., weight-average molecular weight 44811. HP-7200H: Manufactured by DIC Corporation, cyclopentadiene novolac type polyfunctional epoxy resin (solid), softening point 82°C, epoxy equivalent 227 g / eq.

[0147] [Elastomer] NX775: Manufactured by Zeon Corporation, carboxy-modified nitrile rubber, weight-average molecular weight 208,000.

[0148] [Curing catalyst] • 2PZ-CN: Manufactured by Shikoku Chemicals Holdings Co., Ltd., 1-cyanoethyl-2-phenylimidazole. [Polymerization initiator] • Perbutyl (registered trademark) P: Manufactured by NOF Corporation, di(2-t-butylperoxyisopropyl)benzene. • San-Aid SI-110: A thermal cation initiator manufactured by Sanshin Chemical Industry Co., Ltd.

[0149] [Carbon Black] • Special Black 4: Gas black manufactured by ORION ENGINEERED CARBONS. [Filler] • YA050C-SM1: Manufactured by Admatex Co., Ltd., nanosilica, surface treated with methacrylic, average particle size 50nm. • K180SM-C1: Manufactured by Admatex Co., Ltd., submicron silica, surface treated with methacrylic, average particle size 0.18 μm. • YA050C-SV6: Manufactured by Admatex Co., Ltd., nanosilica, surface-treated vinyl, average particle size 50nm. • 3SM-C18: Manufactured by Admatex Co., Ltd., submicron silica, surface treated with methacrylic, average particle size 0.3 μm. • SC1500-SXJ: Manufactured by Admatex Co., Ltd., submicron silica, surface treated with phenylaminophosphate, average particle size 0.3 μm.

[0150] [solvent] • MEK: Methyl ethyl ketone, manufactured by Junsei Chemicals. PGM: Propylene glycol monomethyl ether, manufactured by Junsei Chemicals.

[0151] <Preparation and evaluation of single-layer films> The raw materials in the formulations shown in Table 1 (on a solids basis) were mixed with a solvent of MEK / PGM = 80 / 20 to prepare a coating solution with a solids concentration of 25% by mass. That is, the total amount of the raw materials in the formulations shown in Table 1 (on a solids basis) was set to 25% by mass of the total amount of the resulting coating solution.

[0152] Each coating solution, prepared according to the above procedure, was applied to the release surface of release PET 1-TR3 (manufactured by Nippa Co., Ltd., 50 μm) using a bar coater to achieve a dry film thickness of 40 μm. It was then dried at 120°C for 5 minutes. The single-layer film, with the coatings applied to the release PET, was heated at 150°C for 1 hour to heat-cur the curable resin layer. The release PET was then peeled off to obtain the cured films of the first and second curable resin layers used in each example and comparative example.

[0153] The coefficient of linear expansion (ppm / K) of the obtained cured film was measured in tensile mode using a thermomechanical analyzer (Hitachi High-Tech Science Co., Ltd., model SII / / SS7100) in accordance with JIS K 7197, under conditions of a load of 50 mN and a heating rate of 5°C / min, in the range from 10°C to 200°C. The coefficient of linear expansion (ppm / K) was determined from the slope in the range from 25°C to 150°C. The results are shown in Table 1.

[0154] Table 1 shows the various raw materials used for the first curable resin layer and the second curable resin layer in each example and comparative example, as well as the coefficients of linear expansion of their cured films. In Table 1, each value in the raw material composition represents parts by mass, where 1 part by mass = 1 g.

[0155] [Table 1]

[0156] <Examples> (Example 1) On the release surface of release PET 1-TR3 (manufactured by Nippa Co., Ltd., 50 μm), a coating solution (raw material 1-1, see Table 1) prepared by the manufacturing method described in <Preparation and Evaluation of Single-Layer Films> above was applied using a bar coater to obtain a dry film thickness of 30 μm. Next, the applied film was dried at 120°C for 5 minutes to obtain a single-layer film in which the second curable resin layer was supported on the release PET. Next, on the release surface of release PET 1-TRE (manufactured by Nippa Co., Ltd., 50 μm), a coating solution (raw material 2-1, see Table 1) prepared by the manufacturing method described in <Preparation and Evaluation of Single-Layer Films> above was applied using a bar coater to obtain a single-layer film in which the first curable resin layer was supported on the release PET.

[0157] Each single-layer film obtained under the above conditions was stacked so that the second curable resin layer and the first curable resin layer were in contact. Lamination was performed using a roll laminator at 60°C to produce a dry film in which release PET, second curable resin layer, first curable resin layer, and release PET were sequentially laminated.

[0158] (Example 2) A dry film was prepared under the same conditions as in Example 1, except that the coating liquid for forming the second curing resin layer was changed from raw material 1-1 to raw material 1-2 (see Table 1).

[0159] (Example 3) A dry film was prepared under the same conditions as in Example 1, except that the coating liquid for forming the second curing resin layer was changed from raw material 1-1 to raw material 1-3 (see Table 1).

[0160] (Example 4) A dry film was prepared under the same conditions as in Example 1, except that the coating liquid for forming the second curing resin layer was changed from raw material 1-1 to raw material 1-4 (see Table 1).

[0161] (Example 5) A dry film was prepared under the same conditions as in Example 1, except that the coating liquid for forming the second curing resin layer was changed from raw material 1-1 to raw material 1-5 (see Table 1).

[0162] (Example 6) A dry film was prepared under the same conditions as in Example 1, except that the coating liquid for forming the second curing resin layer was changed from raw material 1-1 to raw material 1-6 (see Table 1).

[0163] (Example 7) A dry film was prepared under the same conditions as in Example 1, except that the coating liquid for the second curable resin layer was changed from raw material 1-1 to raw material 1-2 (see Table 1), and the coating liquid for the first curable resin layer was changed from raw material 2-1 to raw material 2-2 (see Table 1).

[0164] (Example 8) A dry film was prepared under the same conditions as in Example 7, except that the dry film thickness of the second curable resin layer was increased to 50 μm and the dry film thickness of the first curable resin layer was decreased to 20 μm.

[0165] (Example 9) The coating solution used to form the second curable resin layer was changed from raw material 1-1 used in Example 1 to raw material 1-2 (see Table 1), the dry film thickness was increased to 70 μm, and a dry film was prepared by attaching only release PET 1-TRE (manufactured by Nippa Co., Ltd., 50 μm) that did not form the first curable resin layer. All other conditions were the same as in Example 1.

[0166] (Example 10) The coating solution used to form the first curable resin layer was increased to 70 μm, compared to the dry film thickness of raw material 2-1 used in Example 1. The second curable resin layer was not provided. A release PET 1-TRE (manufactured by Nippa Co., Ltd., 50 μm) was applied to the first curable resin layer to produce a dry film. All other conditions were the same as in Example 1.

[0167] <Comparative Example> (Comparative Example 1) A dry film was prepared by changing the raw material 2-1 used in Example 10 to raw material 2-2 in the coating solution for the first curable resin layer. All other conditions were the same as in Example 10.

[0168] <Evaluation component-equipped substrate> A sapphire glass substrate, used as a transparent substrate, was used to create an evaluation substrate with multiple LED light-emitting elements measuring 0.1 x 0.2 mm and 65 μm in height. The LED light-emitting elements were fixed with their top surfaces facing the transparent substrate. As a result, the electrodes of the LED light-emitting elements were on the opposite side from the transparent substrate.

[0169] <Evaluation of each example and comparative example> The release PET (PET 1-TRE) from the dry film according to each of the above examples and comparative examples was peeled off, and the exposed curable resin layer was positioned in contact with the LED light-emitting element.

[0170] Subsequently, a dry film was pressed and filled between the light-emitting elements using a vacuum press under the conditions of 100 hPa vacuum, 100°C, 0.36 MPa, and 3 minutes. Then, the curable resin layer was heat-cured by heating in a 150°C oven for 1 hour, and the remaining release PET 1-TR3 was peeled off.

[0171] The following conformability was evaluated for each example and comparative example after filling and after heat curing.

[0172] [Followability] For light-emitting electronic components, the cross-section was polished using a cross-section polishing machine (Automet 250, manufactured by Bühler) so that the LED light-emitting element was visible in the cross-section. The presence or absence of voids was then observed at 1000x magnification using a microscope (product name: VHX-8000, manufactured by Keyence Corporation). Based on the observation results, the filling ability of the hardened layer was evaluated in the following three stages: A, B, and C in order of decreasing conformability. A and B were considered acceptable. C was considered unacceptable. The evaluation results are shown in Table 2. A: Cross-sectional observation shows that it is filled without any gaps. B: Cross-sectional observation reveals no voids, but surface irregularities are observed where the LED light-emitting element is located, causing it to bulge. C: A void is observed in the cross-section.

[0173] [Chemical resistance] In addition to the conformability evaluation described above, chemical resistance was evaluated according to the following procedure. Samples for chemical resistance testing were prepared by peeling off a square dry film release PET (PET 1-TRE) in a plan view with sides of 30 mm, and then heat-pressing and curing the exposed curable resin layer so that it was in contact with a glass plate. Heat-pressing was performed using a vacuum press at a vacuum of 100 hPa, 100°C, 0.36 MPa for 3 minutes. After that, the curable resin layer was heat-cured by heating in a 150°C oven for 1 hour, and the remaining release PET 1-TR3 was peeled off. Next, each sample was immersed in N-methyl-2-pyrrolidone (NMP) and heated in an 80°C oven for 22 hours. After heating, each sample was removed from the NMP which had returned to room temperature, wiped off the NMP, and then weighed to calculate the weight change rate of the dry film before and after immersion. Chemical resistance was evaluated according to the following criteria. The evaluation results are shown in Table 2. A: Weight change is 20% or less. B: Weight change is between 20% and 50%. C: Weight change exceeds 50% or delamination is observed.

[0174] Table 2 shows the various raw materials used for the first curable resin layer and the second curable resin layer in each example and comparative example, the thickness of each layer, and the results of the dry film evaluation.

[0175] [Table 2]

[0176] As shown in Table 2, while the comparative examples showed good conformability, they exhibited poor chemical resistance. In contrast, Example 9 showed poor conformability but excellent chemical resistance. Examples 1-8 and Example 10 showed that both conformability and chemical resistance met acceptable levels (A or B). [Industrial applicability]

[0177] This invention can be used in the manufacture of light-emitting electronic components that have multiple light-emitting elements. [Explanation of Symbols]

[0178] 1...Dry film, 2...Substrate with element, 3...Cured dry film, 5...Light-emitting electronic component, 10...First curable resin layer (curable resin layer), 11...Second curable resin layer (curable resin layer), 12,13...Protective sheet, 20...Substrate, 21,22,23...Light-emitting element, 24...Light-emitting surface, 25...Electrode, 30...First resin layer, 31...Second resin layer.

Claims

1. A dry film is pressed onto a substrate with multiple light-emitting elements, where the light-emitting surfaces of the elements are fixed to the substrate, from the electrode side opposite to the light-emitting surface. The dry film comprises a curable resin layer, The dry film is characterized in that the curable resin layer comprises a curable resin composition, a filler having radical polymerizable functional groups on its surface, and a polymerization initiator.

2. The dry film according to claim 1, characterized in that the filler is an inorganic filler.

3. The dry film according to claim 2, characterized in that the inorganic filler contains silica.

4. The dry film according to claim 2, characterized in that the average particle size of the inorganic filler is 100 μm or less.

5. The dry film according to claim 2, characterized in that the amount of inorganic filler blended is 40 to 95 parts by mass per 100 parts by mass of the total resin solids of the curable resin layer.

6. The dry film according to claim 1, characterized in that the curable resin composition contains a polyfunctional epoxy resin.

7. The dry film according to claim 6, characterized in that the amount of the polyfunctional epoxy resin blended is 10 to 60 parts by mass per 100 parts by mass of the total resin solids content of the curable resin layer.

8. The dry film according to claim 1, characterized in that the curable resin layer contains an elastomer.

9. The dry film according to claim 8, characterized in that the amount of elastomer blended is 0.1 to 20 parts by mass per 100 parts by mass of the total resin solids content of the curable resin layer.

10. The dry film according to claim 1, characterized in that the polymerization initiator is a cationic polymerization initiator that generates radicals during cationic polymerization.

11. The dry film according to claim 1, characterized in that the amount of polymerization initiator blended is 0.001 to 5 parts by mass per 100 parts by mass of the total resin solids content of the curable resin layer.

12. The dry film according to claim 1, characterized in that the curable resin layer comprises a first curable resin layer arranged on the side closer to the light-emitting surface and a second curable resin layer arranged on the side closer to the electrode, laminated together.

13. The dry film according to claim 12, characterized in that the coefficient of linear expansion after curing of the second curable resin layer is 90 ppm / K or less.

14. Both the first curable resin layer and the second curable resin layer contain an inorganic filler. The dry film according to claim 12, characterized in that the inorganic filler content of the second curable resin layer is greater than the inorganic filler content of the first curable resin layer.

15. The dry film according to claim 12, characterized in that the storage modulus of the second curable resin layer is greater than the storage modulus of the first curable resin layer.

16. The dry film according to claim 15, characterized in that at 100°C, the storage modulus of the second curable resin layer is greater than the storage modulus of the first curable resin layer, and at 150°C, the storage modulus of the second curable resin layer is greater than the storage modulus of the first curable resin layer.

17. The storage modulus of the first curable resin layer is 1.0 × 10 at 100°C. ５ The dry film according to claim 15, characterized in that it is Pa or less.

18. The storage modulus of the second curable resin layer is 1.0 × 10 at 100°C. ７ The dry film according to claim 15, characterized in that it is Pa or less.

19. A substrate with multiple light-emitting elements, with the light-emitting side of each element fixed to the substrate, A film after curing of a dry film according to any one of claims 1 to 18, comprising a dry film cured product pressed onto the side of the element-equipped substrate on which the plurality of light-emitting elements are arranged, A light-emitting electronic component characterized by comprising the following features.

20. A step of pressing a dry film according to any one of claims 1 to 18 onto the side of an element-equipped substrate on which the multiple light-emitting elements are arranged, the light-emitting side of the multiple light-emitting elements is fixed to the substrate, A step of filling the curable resin layer between the plurality of light-emitting elements, A step of curing the aforementioned curable resin layer, A method for manufacturing light-emitting electronic components, characterized by including the following:

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