Electronic component coating sheet, electronic component coating sheet for pressureless processing, electronic component mounting substrate, and method for manufacturing the same.

Abstract

The present invention provides an electronic component coating sheet, an electronic component mounting substrate, and a method for manufacturing the same, which can be used to coat electronic components under atmospheric pressure, have high coating properties, and can be sealed with high dimensional accuracy. [Solution] The solution is provided by an electronic component covering sheet for forming the sealing layer of an electronic component mounting substrate, which comprises a substrate, electronic components mounted on the substrate, and a sealing layer covering at least a portion of the electronic components and the substrate, wherein the electronic component covering sheet has a thermal fluid layer in which the measured time-storage modulus (G') curve and the measured time-loss modulus (G") curve form two intersection points, and the minimum melt viscosity η0 is 0.1 Pa·s or more and 500 Pa·s or less.

Description

[Background technology]

[0001] Electronic components such as IC chips mounted on circuit boards have traditionally been protected from bending, impact, and thermal shock caused by temperature changes by encapsulating them using liquid encapsulants. However, in recent years, the miniaturization of mounting boards and the increased integration of chips due to the enhanced functionality of modules have led to a demand for high dimensional accuracy in resin encapsulation. Conventional liquid encapsulants have suffered from a decrease in encapsulation accuracy (dimensional stability) due to the spreading of molten resin. In addition, the flow of the resin tends to result in uneven encapsulation thickness, leading to problems such as uneven filling between components and the occurrence of voids.

[0002] As a means of solving these problems, for example, Patent Document 1 discloses a thermosetting resin sheet whose minimum melt viscosity at 50°C to 150°C is specified to be within a predetermined range, for use in a semiconductor device manufacturing method that includes a step of covering a semiconductor chip with a thermosetting resin sheet while applying pressure under heating, and filling the gap between the substrate and the semiconductor chip with the thermosetting resin sheet. However, in particular when the substrate has electronic components such as semiconductor chips on both sides, the pressure of the pressing process can distort the substrate or damage the electronic components on the opposite side of the sealing surface, so there have been problems with the practicality of electronic component covering sheets that require pressure molding. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2015-216229 [Overview of the project] [Problems that the invention aims to solve]

[0004] Heat-meltable electronic component coating sheets do not contain solvents and can be molded by heating. This characteristic eliminates the need for heat pressing in the encapsulation process, making them easy to apply to double-sided circuit boards. Therefore, as electronic components and circuit boards become more high-performance and smaller, the demand for heat-meltable electronic component coating sheets is increasing.

[0005] This disclosure is made in view of the above background, and aims to provide an electronic component coating sheet, an electronic component mounting substrate, and a method for manufacturing the same, which can be used to coat electronic components under atmospheric pressure, have high coating properties, and can be sealed with high dimensional accuracy. [Means for solving the problem]

[0006] After diligent research by the present inventors, we have found that the problems of this disclosure can be solved in the following embodiments, and have completed this disclosure. [1] An electronic component covering sheet for forming the sealing layer of an electronic component mounting substrate, comprising a substrate, an electronic component mounted on the substrate, and a sealing layer covering at least a portion of the electronic component and the substrate, The aforementioned electronic component covering sheet has a thermal fluid layer, The aforementioned thermal fluid bed, in dynamic viscoelasticity measurements in accordance with JIS K 7244-10:2005, Measurements were taken under the following temperature profile conditions. The measurement time-storage modulus (G') curve and the measurement time-loss modulus (G") curve are, An electronic component coating sheet that forms two intersection points and has a minimum melt viscosity η0 of 0.1 Pa·s or more and 500 Pa·s or less. Temperature profile: Heat from 30°C to 140°C at a rate of 50°C / min, then maintain at 140°C for 3 hours. [2]: In the dynamic viscoelasticity measurement of the thermal fluid bed, let T0 be the time at which the minimum melt viscosity η0 is reached, T1 be the time at which the curve of G' and the curve of G'' intersect before T0, and T2 be the time at which the curve of G' and the curve of G'' intersect after T0, 10 < [T2-T1] < 175 [minutes] The electronic component covering sheet described in [1]. [3]: The electronic component covering sheet according to [2], wherein T2 is 180 minutes or less. [4]: The electronic component coating sheet according to any one of [1] to [3], wherein the electronic component coating sheet contains a curing accelerator (C), the melting point of the curing accelerator is 40°C or higher and 260°C or lower, and contains one or more selected from the group consisting of aromatic amine compounds, imidazole compounds, isocyanate compounds, aziridine compounds, and dicyandiamidoamine compounds. [5]: The electronic component coating sheet according to any one of [1] to [4], wherein the curve of tanδ obtained by the dynamic viscoelasticity measurement of the thermal fluid layer has two maximum peaks. [6]: An electronic component coating sheet according to any one of [1] to [5], wherein the maximum value of tanδ obtained by the dynamic viscoelasticity measurement of the thermal fluid layer is 1 or greater. [7]: The electronic component coating sheet according to any one of [1] to [6], wherein the minimum melt viscosity η0 of the thermal fluid bed at 140°C is 1.0 Pa·s or more and 50 Pa·s or less. [8]: The electronic component covering sheet according to any one of [1] to [7], wherein the process of forming the sealing layer of the electronic component mounting substrate using the electronic component covering sheet is carried out under atmospheric pressure in a non-pressure processing manner. [9]: A substrate comprising a substrate, an electronic component mounted on the substrate, and a sealing layer covering at least a portion of the electronic component and the substrate, wherein the sealing layer is formed from a cured product of an electronic component covering sheet according to any one of [1] to [8].

[10] : A method for manufacturing an electronic component mounted substrate comprising a substrate, an electronic component mounted on the substrate, and a sealing layer covering at least a part of the electronic component and the substrate, comprising the steps of placing an electronic component covering sheet according to any one of [1] to [8] on the substrate on which the electronic component is mounted, A method for manufacturing an electronic component mounting substrate, comprising the steps of: forming a sealing layer that covers at least a portion of the electronic component and the substrate using the electronic component covering sheet; and curing the sealing layer. [Effects of the Invention]

[0007] The present disclosure has been made in view of the above background, and provides a heat-meltable sealing sheet that can be applied to a double-sided mounting substrate and can be resin-sealed with high dimensional accuracy.

Brief Description of the Drawings

[0008] [Figure 1] A schematic cross-sectional view showing an example of an electronic component mounting substrate according to the present embodiment. [Figure 2] A schematic cross-sectional view showing another example of an electronic component mounting substrate according to the present embodiment. [[ID=十六]] [Figure 3] A schematic cross-sectional view showing an example of an electronic component coating sheet according to the present embodiment. [Figure 4] A schematic cross-sectional view showing another example of an electronic component coating sheet according to the present embodiment. [Figure 5] A schematic cross-sectional view showing yet another example of an electronic component coating sheet according to the present embodiment. [Figure 6] A graph showing an example of a time-elastic modulus displacement curve obtained by dynamic viscoelasticity measurement. [Figure 7] A graph showing an example of a time-complex viscosity displacement curve obtained by dynamic viscoelasticity measurement.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, an example of an embodiment to which the present disclosure is applied will be described. In this specification, the numerical range indicated by "~" includes the numerical values described before and after it as the minimum value and the maximum value, unless otherwise specified. The drawings are appropriately simplified for clarity of explanation, and the scales of each component may be different. Various components described in this specification can be used alone or in combination of two or more, unless otherwise noted. When two or more are used in combination, the total content is used. In addition, the numerical values specified in this specification are values obtained by the methods of the examples described later.

[0010] <Electronic Component Coating Sheet> The electronic component covering sheet according to this disclosure (the covering sheet) is suitably used as a sheet for forming the sealing layer of an electronic component mounting substrate, which comprises a substrate, an electronic component mounted on the substrate, and a sealing layer covering at least a portion of the electronic component and the substrate.

[0011] Figures 1 to 3 show three examples of schematic cross-sectional views of electronic component coating sheets according to this disclosure. The electronic component coating sheet 10 shown in Figure 1 consists of a single layer, a first layer 11. The electronic component coating sheet 10a shown in Figure 2 has a laminated structure of a first layer 21 and a second layer 22. The electronic component coating sheet 10b shown in Figure 3 has a laminated structure in which a first layer 31, a second layer 32, and a third layer 33 are laminated in that order. The number of layers may be four or more. The electronic component coating sheet may have a release sheet on one or both sides for surface protection.

[0012] This covering sheet is an insulating sheet that physically protects electronic components and can also provide them with specific functions. If the electronic component covering sheet is multilayered, each layer may have the same function or different functions.

[0013] Each layer of this coating sheet can be given various functions such as heat dissipation, light shielding, moisture resistance, decorative properties, hard coating properties, flame retardancy, and gas barrier properties. These properties can be provided, for example, by selecting an inorganic filler (F) as described later. The layer of this coating sheet placed on the electronic component side preferably has excellent adhesion to the electronic component.

[0014] [Thermal fluid bed] This coating sheet has a thermal fluid layer. When the electronic component coating sheet is multi-layered, it is preferable that the thermal fluid layer be located on the electronic component side.

[0015] In dynamic viscoelasticity measurements of the aforementioned thermal fluid bed in accordance with JIS K 7244-10:2005, the measurement time-storage modulus (G') curve and the measurement time-loss modulus (G") curve, measured under the following temperature profile conditions, form two intersection points, and the minimum melt viscosity η0 is 0.1 Pa·s or more and 500 Pa·s or less. Temperature profile: Heat from 30°C to 140°C at a rate of 50°C / min, then maintain at 140°C for 3 hours.

[0016] In the dynamic viscoelasticity measurement of the thermal fluidized layer, the measurement time-storage modulus (G') curve and the measurement time-loss modulus (G") curve form two intersection points, allowing the layer to maintain its sheet shape before processing while flowing only during processing to coat electronic components. Furthermore, by setting the minimum melt viscosity η0 at 140°C within the range of 0.1 Pa·s to 500 Pa·s, excessive flow of the thermal fluidized layer can be suppressed. As a result, only the electronic components to be coated can be processed, and a sealing layer can be formed without exposing electronic components or creating gaps between components.

[0017] The lower limit of the minimum melt viscosity η0 at 140°C of the thermal fluid bed is preferably 0.5 Pa·s, more preferably 1.0 Pa·s, and even more preferably 5.0 Pa·s. The upper limit of the minimum melt viscosity η0 at 140°C is preferably 400 Pa·s, more preferably 300 Pa·s, and even more preferably 50 Pa·s.

[0018] In this coating sheet, the minimum melt viscosity η0 of the thermal fluid layer at 140°C can be controlled by, for example, the type of thermosetting resin (R), glass transition temperature (Tg), weight-average molecular weight (Mw), acid value, type of curable compound (X), softening point or melting point, etc., as described later. For example, a lower Tg of the thermosetting resin (R) tends to result in a lower minimum melt viscosity η0, while a higher Tg of the thermosetting resin (R) tends to result in a higher minimum melt viscosity η0. Furthermore, using a liquid epoxy compound at room temperature as the curable compound (X) tends to result in a lower minimum melt viscosity η0, while using a solid epoxy compound at room temperature tends to result in a higher minimum melt viscosity η0. Furthermore, the minimum melt viscosity η0 can be adjusted by the type of filler (F), particle size, particle shape, and amount added. To lower the minimum melt viscosity η0, for example, increasing the amount of thermosetting resin (R) with a Tg below room temperature, or decreasing the amount of filler (F), are effective methods. To increase the minimum melt viscosity η0, the opposite adjustments can be made.

[0019] In the dynamic viscoelasticity measurement, when T0 is the time at which the minimum melt viscosity η0 is reached in the thermal fluid bed, T1 is the time at which the curves of G' and G'' intersect before T0, and T2 is the time at which the curves of G' and G'' intersect after T0, The interval is 10 < [T2-T1] < 175 [minutes]. In dynamic viscoelasticity measurements, the sample is fluid while G' > G''. Therefore, [T2-T1] can be evaluated as an indicator of the flow time of this coating sheet.

[0020] The lower limit of [T2-T1] is preferably 15 minutes, more preferably 20 minutes, and even more preferably 25 minutes. The upper limit of [T2-T1] is preferably 150 minutes, more preferably 140 minutes, and even more preferably 130 minutes. By setting [T2-T1] within the above range, the fluidity of the coating sheet can be controlled, and a sealing layer can be formed without exposing the processed electronic components.

[0021] The aforementioned T2 may be 180 minutes or less, preferably 170 minutes or less, more preferably 160 minutes or less, and even more preferably 150 minutes or less. When T2 is 180 minutes or less, the processing is completed in a shorter time, thus improving productivity.

[0022] In this coated sheet, the control required to satisfy [T2-T1] can be adjusted, for example, by the type of thermosetting resin (R), weight-average molecular weight Mw, glass transition temperature (Tg), acid value, and type of curable compound (X). Furthermore, it can be adjusted by the type and amount of curing accelerator (C) and the amount of filler (F). Methods for shortening [T2-T1] include, for example, accelerating the curing reaction to shorten T2. ​​Effective methods include using a polyfunctional curable compound (X), increasing the amount of curable compound (X), using a curing accelerator (C) with a lower melting point, and increasing the amount of curing accelerator (C). One way to extend [T2-T1] is to extend T2, for example; therefore, the adjustment should be reversed from the above. Furthermore, since the T1 can also be adjusted by increasing the fluidity component contained in the thermal fluid layer of the coating sheet, it is effective to use an epoxy compound that is liquid at room temperature as the curable compound (X), and to use a thermosetting resin (R) with a lower Tg.

[0023] The tanδ curve obtained from the dynamic viscoelasticity measurement of the thermal fluid layer has two maximum peaks. Although the detailed mechanism is not clear, it is thought to be due to the glass transition temperatures of multiple resin components in the thermal fluidized bed. It is believed that as the multiple resin components in the thermal fluidized bed flow and become more miscible, the uniformity of the coating sheet increases, resulting in good coating performance on electronic components.

[0024] Furthermore, it is preferable that the maximum value of tanδ obtained by the dynamic viscoelasticity measurement of the thermal fluid layer is 1.0 or greater. When the maximum value of tanδ is 1.0 or greater, the fluidity of the thermal fluid layer is sufficient, and a sealing layer can be formed without the electronic components being exposed or gaps being created between the components.

[0025] The thermal fluid layer of this coating sheet contains a curing accelerator (C), the curing accelerator (C) having a melting point of 40°C or higher and 260°C or lower, and containing one or more selected from the group consisting of aromatic amine compounds, imidazole compounds, isocyanate compounds, aziridine compounds, and dicyandiamidoamine compounds.

[0026] [Protective layer] From the viewpoint of freely adjusting the coverage, dimensional stability, and short-time processability of the sealing layer formed from this coating sheet over electronic components, it is preferable that the coating sheet be multi-layered, and that a protective layer be provided on the surface opposite to the surface facing the electronic component.

[0027] If the covering sheet has a protective layer on the surface opposite to the surface facing the electronic component, the minimum melt viscosity η0′ of the protective layer at 140°C is 5.0 × 10 4 Pa·s or more 5.0×10 5 It is sufficient if it is less than or equal to Pa·s, 7.0 × 10 4 Pa·s or more 4.0×10 5 Preferably Pa·s or less, 1.0 × 10 5 Pa·s or more 3.0×10 5 Pa·s or less is more preferable, and 1.5 × 10 5 Pa·s or more 2.5×10 5 A range of Pa·s or less is even more preferable. By setting the range to the above, it becomes easier to control the coverage of the sealing layer on electronic components, dimensional stability, and short-time processability.

[0028] In this coating sheet, the control of the minimum melt viscosity η0′ of the protective layer at 140°C can be carried out in the same manner as the control method for the minimum melt viscosity η0 of the thermal fluid layer at 140°C.

[0029] The thickness of this coating sheet can be designed as appropriate depending on the application. For applications where thinness is required, the thickness of this coating sheet covering the top and sides of electronic components is preferably 5 μm to 500 μm, more preferably 10 μm to 300 μm, and even more preferably 15 μm to 250 μm.

[0030] This coated sheet is composed of an insulating layer as described above. The surface resistance value of the insulating layer is preferably 1.0×10 7 Ω / sq or more, more preferably 1.0×10 8 Ω / sq or more, and even more preferably 1.0×10 9 Ω / sq or more.

[0031] The heat-flowable layer of this coated sheet contains a binder component that serves as the base of the sealing layer. As the binder component, a thermosetting resin (R) is exemplified. In addition to the self-crosslinking thermosetting resin (R), a thermosetting resin (R) that can react with a curable compound (X) is suitable. It is also possible to combine these. In particular, a combination of a thermosetting resin (R) and a curable compound (X) is suitable as the binder component. When using the curable compound (X), a thermosetting resin (R) having a reactive functional group and capable of reacting with the curable compound (X) is suitable.

[0032] [Thermosetting resin (R)] The weight average molecular weight (Mw) of the thermosetting resin (R) is not limited, but is preferably 10,000 or more and 1,000,000 or less. The lower limit of the Mw is more preferably 20,000, even more preferably 25,000, and even more preferably 30,000. The upper limit of the Mw is more preferably 500,000, even more preferably 250,000, and even more preferably 200,000 or less, 150,000 or less. By setting the Mw of the thermosetting resin (R) to 1,000,000 or less, the entanglement of molecular chains is likely to be unraveled during the thermo-processing of this coated sheet, and the coating property to electronic components is improved. By setting the Mw of the thermosetting resin (R) to 10,000 or more, the coating film strength of this coated sheet can be increased.

[0033] The thermosetting resin (R) can be used alone or in combination of two or more types. The content of the thermosetting resin (R) is not limited, but it is preferably 15% by mass or more and 95% by mass or less based on the total amount (100% by mass) of the coating sheet. The lower limit of the content is more preferably 25% by mass, 35% by mass, 45% by mass, and 50% by mass, and even more preferably 60% by mass and 70% by mass. The upper limit of the content is preferably 90% by mass and 85% by mass, and even more preferably 80% by mass. By setting the content of the thermosetting resin (R) in the coating sheet to 15% by mass or more, the film-forming properties of the coating sheet can be improved, and by setting it to 95% by mass or less, the coating properties on electronic components can be improved.

[0034] The glass transition temperature (Tg) of the thermosetting resin (R) is not limited, but is preferably between -30°C and 80°C, more preferably between -20°C and 70°C, and even more preferably between -15°C and 50°C. Setting the Tg to between -30°C and 80°C improves the fluidity of the coating sheet, resulting in better coating properties for electronic components.

[0035] Preferred examples of thermosetting resins (R) include polyurethane resins, polyurethane urea resins, phenoxy resins, (meth)acrylic resins, polyester resins, polyamide resins, epoxy resins, polystyrene resins, polycarbonate resins, polyamide-imide resins, polyesteramide resins, polyether ester resins, alkyd resins, polyimide resins, benzoxazine resins, amino resins, polylactic acid resins, oxazoline resins, silicone resins, and fluororesins. From the viewpoint of improving the fluidity of the coating sheet and the coating properties of the sealing layer over electronic components, among these, the thermosetting resins (R) that are most preferably polyurethane resins including polyurethane resins and polyurethane urea resins, or (meth)acrylic resins including (meth)acrylic acid esters, (meth)acrylic acid esters, (meth)acrylonitrile, and (meth)acrylamide.

[0036] a. Polyurethane resins Polyurethane resins are resins containing two or more urethane bonds in one molecule. Polyurethane resins can be obtained by reacting a polyisocyanate with a polyol. The polyisocyanate only needs to have two or more isocyanate groups in one molecule, and from the viewpoint of uniform dispersion of the coating sheet, diisocyanate or triisocyanate is preferred, with diisocyanate being more preferred. As the diisocyanate, it can be appropriately selected from known aliphatic diisocyanates such as hexamethylene diisocyanate or known aromatic diisocyanates such as benzene-1,3-diisocyanate. Alternatively, an isocyanate-terminated prepolymer obtained by reacting a polyol with an excess of polyisocyanate may be used as an intermediate for the urethane resin. The polyol can be any polyol having two or more hydroxyl groups in one molecule, and diols or triols are preferred, with diols being more preferred. As the diol, it can be appropriately selected from known aliphatic diols such as ethylene glycol or known aromatic diols such as benzenediol. In addition, prepolymers such as polyether polyols, polyester polyols, and polycarbonate polyols may be used.

[0037] The polyurethane resin may also be a polyurethane urea resin having urea bonds. Polyurethane urea resin can be synthesized, for example, by reacting a polyamine with a urethane resin having isocyanate groups at its terminals. Polyamines can be any polyamine having two or more amino groups in one molecule. From the viewpoint of dispersibility, diamines or triamines are preferred, and diamines are more preferred. As for diamines, they can be appropriately selected from known aliphatic diamines such as ethylenediamine and known aromatic diamines such as phenylenediamine.

[0038] Polyurethane resins preferably have reactive functional groups such as hydroxyl groups, carboxyl groups, and epoxy groups, and more preferably have carboxyl groups. Furthermore, polyurethane resins having urethane bonds and ester bonds, and polyurethane urea resins having urethane bonds, urea bonds, and ester bonds are more preferable from the viewpoint of improving the coverage of the sealing layer and reducing warping. Polyurethane resins can be produced, for example, by the method described in the examples. Polyurethane resins having ester bonds can be obtained, for example, by synthesizing a polyester polyol by condensation reaction of a polyol and a polycarboxylic acid, and then reacting the obtained polyester polyol with a polyisocyanate. Polyurethane urea resins having ester bonds can be obtained, for example, by reacting the aforementioned polyester polyol with a polyisocyanate and then reacting it with a polyamine.

[0039] [Curable compound (X)] The curable compound (X) is a resin or compound having reactive functional groups and a weight-average molecular weight (Mw) of less than 10,000, and may be a low-molecular-weight compound. The curable compound (X) can be used alone or in combination of two or more types. Preferably, the curable compound (X) has functional groups that can react with the thermosetting resin (R). Through curing treatment, the functional groups of the curable compound (X) thermally crosslink with reactive functional groups such as carboxyl groups and hydroxyl groups of the thermosetting resin (R), thereby obtaining a crosslinked structure.

[0040] The curable compound (X) preferably has multiple of the aforementioned functional groups. Examples of curable compound (X) include epoxy compounds, isocyanate compounds, polycarbodiimide compounds, aziridine compounds, imidazole compounds, acid anhydride group-containing compounds, dicyandiamide compounds, amine compounds such as aromatic diamine compounds, phenolic compounds such as phenol novolac resins, and organometallic compounds. Among these, epoxy compounds, phenolic compounds, organometallic compounds, and aziridine compounds are preferred, and epoxy compounds are more preferred from the viewpoint of easily controlling the fluidity of the coated sheet and improving adhesion after curing.

[0041] The epoxy compound is not particularly limited, but epoxy compounds having an N atom, such as glycidylamine, and epoxy compounds having a hydroxyl group are preferred. The number of functional groups in the epoxy group is preferably two or more. The epoxy equivalent of the epoxy compound is not limited, but from the viewpoint of heat resistance, it is preferably 100 g / eq to 1000 g / eq, and more preferably 150 g / eq to 500 g / eq.

[0042] Examples of glycidylamines include N-glycidyl compounds obtained by the reaction of an aromatic amine (such as aniline and toluidine) having 6 to 20 carbon atoms and 2 to 4 active hydrogen atoms with epichlorohydrin. Specifically, tetraglycidylamine phenylmethane, triglycidyl-p-aminophenol, and tetraglycidyl-m-xylenediamine are also suitable. Examples of commercially available products include SumiEpoxy ELM-100, ELM-120 (both trade names, manufactured by Sumitomo Chemical Co., Ltd.), MY721 (trade name, manufactured by Ciba Specialty Chemicals), TETRAD-X and TETRAD-C (trade names from Mitsubishi Gas Chemical Co., Ltd.), and GAN (trade name from Nippon Kayaku Co., Ltd.).

[0043] Examples of difunctional epoxy compounds include bisphenol diglycidyl ethers such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol E diglycidyl ether, bisphenol Z diglycidyl ether, bisphenol S diglycidyl ether, bisphenol AD ​​diglycidyl ether, bisphenol acetophenone diglycidyl ether, bisphenol trimethylcyclohexane diglycidyl ether, bisphenol fluoroorange diglycidyl ether, tetramethylbisphenol A diglycidyl ether, tetramethylbisphenol F diglycidyl ether, tetra-t-butylbisphenol A diglycidyl ether, and tetramethylbisphenol S diglycidyl ether; biphenol diglycidyl ethers such as biphenol diglycidyl ether, tetramethylbiphenol diglycidyl ether, dimethylbiphenol diglycidyl ether, and tetra-t-butylbiphenol diglycidyl ether; hydroquinone diglycidyl ether, dihydroquinone diglycidyl ether, and dihydroquinone diglycidyl ether. Benzene diglycidyl ethers such as dianthracene diglycidyl ether, methyl hydroquinone diglycidyl ether, dibutyl hydroquinone diglycidyl ether, resorcinol diglycidyl ether, and methyl resorcinol diglycidyl ether; aromatic diglycidyl ethers such as dihydroanthrahydroquinone diglycidyl ether, dihydroxydiphenyl ether diglycidyl ether, thiodiphenol diglycidyl ether, and dihydroxynaphthalene diglycidyl ether; Epoxy compounds obtained by adding hydrogen to the aromatic ring of diglycidyl ethers selected from bisphenol-based diglycidyl ethers, biphenol-based diglycidyl ethers, benzenediol-based diglycidyl ethers, and aromatic diglycidyl ethers; epoxy resins produced from various carboxylic acids such as adipic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, biphenyldicarboxylic acid, and dimer acid, and epihalohydrins;Examples include (poly)alkylene glycol diglycidyl ethers consisting solely of chain structures, such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, 1,5-pentanediol diglycidyl ether, polypentamethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, 1,7-heptanediol diglycidyl ether, polyheptamethylene glycol diglycidyl ether, 1,8-octanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, and 2,2-dimethyl-1,3-propanediol diglycidyl ether; and alkylene glycol diglycidyl ethers having cyclic structures, such as 1,4-cyclohexanedimethanol diglycidyl ether. Examples of commercially available products include DIC's EPICLON 830, 840, 850, 860, 1050, 2050, 3050, 4050, 7050, HM-091, 101; Nagase ChemteX's Denacol EX-211, 212, 252, 711, 721; and Mitsubishi Chemical's jER1001.

[0044] As the epoxy compound, from the viewpoint of controlling the fluidity of the coating sheet and improving its coating properties to electronic components, epoxy compounds that are liquid at 25°C or epoxy compounds with a softening point of 100°C or lower are preferred. Specific examples include liquid bisphenol-type epoxy resins such as "jER1001" (epoxy equivalent 470 g / eq, solid, softening point 64°C) manufactured by Mitsubishi Chemical Corporation, "R140P" (epoxy equivalent 188 g / eq, liquid) manufactured by Mitsui Chemicals, "DER383, liquid" manufactured by Dow Chemical Corporation, and "Epicote #807, liquid" (epoxy equivalent 170 g / eq) manufactured by Japan Epoxy Resin Co., Ltd.

[0045] The content of the curable compound (X) is preferably 5 parts by mass or more and 250 parts by mass or less, and more preferably 10 parts by mass or more and 100 parts by mass or less, per 100 parts by mass of thermosetting resin (R). By setting it within the above range, the fluidity of the coating sheet can be easily controlled, resulting in good coating properties for electronic components and dimensional stability of the sealing layer.

[0046] [Curing accelerator (C)] The thermal fluid layer of the coating sheet preferably contains a curing accelerator (C) in addition to the curable compound (X). The curing accelerator (C) can be one that reacts with the epoxy resin to cure. Examples of curing accelerators (C) include amines, phenolic curing agents, active ester curing agents such as acid anhydrides, polymercaptan compounds, isocyanate compounds, and organic acids. Among these, from the viewpoint of easily controlling fluidity, it is preferable to include one or more selected from the group consisting of aromatic amine compounds, imidazole compounds, isocyanate compounds, aziridine compounds, and dicyandiamideamine compounds.

[0047] Aromatic amine compounds are not limited to, but include, for example, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 2,2'-diaminodiphenylsulfone, diethyltoluenediamine, dimethylthiotoluenediamine, diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetramethyldiphenylmethane, 4, Examples include 4'-diamino-3,3',5,5'-tetraisopropyldiphenylmethane, 4,4'-methylenebis(N-methylaniline), bis(aminophenyl)fluorene, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 1,3'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)biphenyl, 4,4'-(1,3-phenylenedisopropylidene)bisaniline, 4,4'-(1,4-phenylenedisopropylidene)bisaniline, naphthalenediamine, benzidine, dimethylbenzidine, etc.

[0048] Aziridine compounds are not limited to, but include, for example, trifunctional aziridines such as trimethylolpropane tris(3-(2-methyl-1-aziridyl)propionic acid) ester, trimethylolpropane tris(3-(1-aziridyl)propionic acid) ester, pentaerythritol tris(3-(2-methyl-1-aziridyl)propionic acid) ester, pentaerythritol tris(3-(1-aziridyl)propionic acid) ester, dipentaerythritol tris(3-(1-aziridyl)propionic acid) ester and sorbitol tris(3-(1-aziridyl)propionic acid) ester; pentaerythritol tetrakis(3-(1- Examples of tetrafunctional aziridines include aziridyl (3-(1-aziridyl)propionic acid) ester, sorbitol tetrakis(3-(1-aziridyl)propionic acid) ester, and ditrimethylolpropane tetrakis(3-(1-aziridyl)propionic acid) ester; pentahylated aziridines include sorbitol pentakis(3-(1-aziridyl)propionic acid) ester and dipentaerythritol pentakis(3-(1-aziridyl)propionic acid) ester; and hexahylated aziridines include dipentaerythritol hexakis(3-(1-aziridyl)propionic acid) ester and sorbitol hexakis(3-(1-aziridyl)propionic acid) ester. A commercially available example is Chemitight PZ-33 (trade name, manufactured by Nippon Shokubai Co., Ltd.).

[0049] The imidazole compounds are not limited to these, but include, for example, Ajinomoto Fine Techno Co., Ltd. products: Amicure PN-23, Amicure PN-23J, Amicure PN-31, Amicure PN-31J, Amicure PN-40, Amicure PN-40J, Amicure PN-50, Amicure PN-H; ADEKA Corporation products: Adeka Hardener EH3293S, Adeka Hardener EH3366S, Adeka Hardener EH4346S; Air Products Japan Co., Ltd. product: Sanmide LH210; Shikoku Chemicals Co., Ltd. Examples of products manufactured by various companies include: Cureazole SIZ, Cureazole 2MZ-H, Cureazole C11Z-A, Cureazole C17Z, Cureazole C11Z, Cureazole 1.2DMZ, Cureazole 2E4MZ, Cureazole 2PZ, Cureazole 2PZ-PW, Cureazole 2MZ-A, Cureazole 2MA-OK, Cureazole 2PHZ, Cureazole 2P4MHZ, Cureazole 2MZ-CN, Cureazole C11Z-CN, Cureazole 2E4MZ-CN, Cureazole 2PZ-CN, etc.

[0050] Imidazole compounds are effective in accelerating the curing reaction before the curing process to some extent, and imidazoles with low activity temperatures and low solvent solubility are preferred in order to maintain a long pot life of the product. Specific examples include the trade names: "Cureazole C17Z" (activity temperature: 85°C), "Cureazole C11Z" (activity temperature: 90°C), "Cureazole 2E4MZ" (activity temperature: 107°C), "Cureazole 2PZ-PW" (activity temperature: 107°C), and "Cureazole 2PHZ-PW" (activity temperature: 157°C). By using these imidazole compounds (Cd), the curing reaction before the curing process can be easily controlled, and the adhesion and fluidity of the coated sheet to electronic components can be easily controlled.

[0051] The isocyanate compounds are not limited to, but include, for example, monofunctional isocyanate compounds such as n-butyl isocyanate, isopropyl isocyanate, phenyl isocyanate, and benzyl isocyanate; Examples include polyfunctional isocyanate compounds such as hexamethylene diisocyanate, toluene diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethane-4,4′-diisocyanate, isophorone diisocyanate, xylylene diisocyanate, paraphenylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and bicycloheptane triisocyanate.

[0052] The dicyandiamidoamine compounds are not limited to those mentioned above, but examples include products manufactured by Mitsubishi Chemical Corporation, such as DICY7, DICY15, and DICY50.

[0053] The content of the curing accelerator (C) is preferably 0.01 parts by mass or more and 5 parts by mass or less, and more preferably 0.1 parts by mass or more and 2 parts by mass, per 100 parts by mass of thermosetting resin (R).

[0054] Furthermore, the ratio (X) / (C) of the curable compound (X) to the curing accelerator (C) is preferably 5 to 500, and more preferably 10 to 200. By setting it within the above range, excessive curing of the thermal fluid layer can be easily suppressed, the coverage of the sealing layer on electronic components can be further improved, and a stronger cross-linked structure can be formed in the sealing layer, thereby improving the strength of the sealing layer. On the other hand, combining the curing accelerator (C) with the curable compound (X) is effective in accelerating the curing reaction before the curing process to some extent, and is expected to extend the pot life of the product. Furthermore, since the residue of unreacted curable compound (C) can be suppressed in the curing reaction after coating electronic components, the heat and moisture resistance of the cured sheet can be effectively exhibited.

[0055] The curing accelerator (C) is preferably a compound with a melting point. The melting point of the curing accelerator (C) is preferably 40°C to 250°C, more preferably 50°C to 150°C, and even more preferably 80°C to 140°C. By setting it within the above range, the fluidity and curability of the coating sheet can be easily controlled, making it easier to control the coating properties of the sealing layer on electronic components and the processing time.

[0056] [Inorganic filler (F)] The thermal fluid layer of this coating sheet may contain an inorganic filler (F) as an optional component. From the viewpoint of improving embedding properties, the content of the inorganic filler (F) (total content if two or more types are included) is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on the total amount of solids in this coating sheet. From the viewpoint of bringing out the properties of the inorganic filler (F), the lower limit of its content is preferably 5% by mass, more preferably 10% by mass, and the lower limit may be 15%, 20%, or 25% by mass.

[0057] The shape of the inorganic filler (F) can be selected as appropriate. Examples include flake-shaped, needle-shaped, spherical, dendritic, and fibrous fillers. Fillers of different shapes may be used in combination. A preferred example is a combination of flake-shaped and spherical fillers.

[0058] Average particle size D of inorganic filler (F) 50 The average particle size D of the inorganic filler (F) is preferably 0.02 μm or more and 10 μm or less, more preferably 0.03 μm or more and 5 μm or less. Even more preferably 0.1 μm or more and 2 μm or less, and particularly preferably 0.2 μm or more and 1 μm or less. 50 This can be measured using a light scattering particle size analyzer such as the "Microtrac MT3000II" (product name; manufactured by Nikkiso Co., Ltd.).

[0059] Examples of inorganic fillers (F) include silica, alumina, titanium oxide, zinc oxide, antimony trioxide, magnesium oxide, tin oxide, zirconium oxide, magnesium hydroxide, barium sulfate, calcium carbonate, talc, kaolinite, mica, sericite, montmorrolinite, bentonite, magnesium carbonate base, boron nitride, aluminum nitride, titanium nitride, magnesium silicon nitride, silicon carbide, titania, glass, ceramics, and carbon. Among these, silica, alumina, titanium oxide, zinc oxide, calcium carbonate, titanium nitride, and carbon are preferred. Two or more inorganic fillers may be combined. A preferred combination is silica with one or more selected from carbon and titanium oxide.

[0060] The inorganic filler (F) may be surface-modified with a surface modifier from the viewpoint of improving dispersibility in the coated sheet. Examples of surface modifiers include organic acids, silane coupling agents, surfactants, titanium coupling agents, and metal impurities, and it is preferable that an organic acid is included. Inorganic filler (F) is preferably used after dispersion treatment. Dispersers used for mechanical crushing for dispersion treatment include ball mills, roll mills, sand mills, bead mills, and nanomizers. Among these, bead mills are preferred. Examples of commercially available bead mills include Super Mill, Sand Grinder, Agitator Mill, Glen Mill, Dyno Mill, Pearl Mill, and Cobol Mill (all are trade names).

[0061] [Other ingredients]

[0062] Furthermore, the coating sheet may contain a tackifying resin to improve adhesion to the substrate. The tackifying resin is a component that supplementarily improves adhesive strength, has a weight-average molecular weight of less than 5,000, and is distinct from the thermoplastic resin and thermosetting resin (R) mentioned above. Examples of tackifying resins include rosin-based resins, terpene-based resins, alicyclic petroleum resins, and aromatic petroleum resins.

[0063] This coating sheet may contain a plasticizer. The plasticizer can improve wrinkles and tears during the molding process of the coating sheet. Examples of plasticizers include fatty acid esters, phthalate esters, aromatic polycarboxylic acid esters, and polyesters.

[0064] This coating sheet may further contain colorants, flame retardants, lubricants, anti-blocking agents, silane coupling agents, antistatic agents, etc. Examples of flame retardants include halogen-containing flame retardants, phosphorus-containing flame retardants, nitrogen-containing flame retardants, and inorganic flame retardants. Examples of lubricants include fatty acid esters, hydrocarbon resins, paraffins, higher fatty acids, fatty acid amides, aliphatic alcohols, metal soaps, and modified silicones. Examples of anti-blocking agents include calcium carbonate, silica, polymethylsilsesquiosan, and aluminum silicate salts. By adding an antistatic agent, the generation of static electricity with other components such as pick-and-place plate members can be suppressed.

[0065] <Method for manufacturing electronic component covering sheets> The method for manufacturing the coating sheet is not particularly limited, but one example is a method of coating a release sheet with a composition obtained by dispersing or dissolving materials such as a thermosetting resin (R) and a curable compound (X), which are binder components that form the sealing layer, in a solvent. Examples of coating methods include gravure coating, kiss coating, die coating, lip coating, comma coating, blade coating, roll coating, knife coating, spray coating, bar coating, spin coating, dip coating, and various printing methods. In the case of multi-layer coatings, known methods such as lamination and lamination via an easy-to-use adhesive can be applied.

[0066] <Applications of electronic component covering sheets> This coating sheet is particularly suitable for coating electronic component mounting substrates, but it may also be used to coat other items to be coated. Electronic component mounting substrates using this coating sheet are preferably incorporated into electronic devices such as liquid crystal displays, touch panels, notebook PCs, mobile phones, smartphones, and tablet terminals.

[0067] <Electronic component mounting substrate and method for manufacturing the same> The electronic component mounting substrate according to this disclosure (hereinafter also referred to as "this mounting substrate") comprises a substrate, electronic components mounted on the substrate, and a sealing layer covering at least a portion of the electronic components and the substrate. The sealing layer is formed using the electronic component covering sheet according to this disclosure (hereinafter also referred to as "this covering sheet"). Hereinafter, Figures 4 and 5 show two examples of schematic cross-sectional views of the electronic component mounting substrate according to this embodiment.

[0068] The electronic component mounting substrate 101 shown in Figure 4 comprises a substrate 41, an electronic component 42 mounted on the substrate 41, and a sealing layer 43. The sealing layer 43 covers the entire exposed surface of one main surface of the electronic component mounting substrate. On the other hand, the electronic component mounting substrate 102 shown in Figure 5 has a sealing layer 43a provided on a part of one main surface of the electronic component mounting substrate. The sealing layer 43a covers a part of the exposed surface of the substrate 41 and one main surface of the electronic component 2. Thus, in this mounting substrate, the sealing layer formed using the electronic component covering sheet according to this disclosure may be provided so as to cover a part of the electronic component and the substrate, or it may be provided so as to cover the entire surface of the electronic component and the substrate.

[0069] The substrate 41 can be any substrate that can mount electronic components 42 and withstand the molding process for each application, and can be arbitrarily selected. Electrode and wiring patterns, vias (not shown), etc., can be optionally provided on the substrate 1. The substrate may be either a rigid substrate or a flexible substrate. Examples include workboards, mounting module substrates, printed circuit boards, and build-up substrates formed by build-up methods, etc., with conductive patterns made of copper foil or the like formed on the surface and / or inside.

[0070] The electronic component 42 is mounted on the main surface of the substrate 41. When multiple electronic components are mounted, their shapes and heights may be the same or different. Specific examples of the electronic component 2 include IC chips, multilayer ceramic chip capacitors (MLCCs), inductors, and thermistors.

[0071] The sealing layers 43 and 43a cover the top and side surfaces of the electronic component 2, and further, the entire or partial surface of one main surface of the substrate 41. In other words, they are applied to follow the stepped portions (uneven portions) formed by the mounting of the electronic component 42, and the sealing layers 43 and 43a are provided on the entire or partial surface of one main surface of the substrate 1. The sealing layers 43 and 43a are formed using the electronic component coating sheet (the coating sheet) according to this disclosure, and are cured products obtained by curing the coating sheet. In this specification, the coating sheet is uncured or semi-cured (so-called B-stage). In contrast, the sealing layers 43 and 43a of the electronic component mounted substrate after manufacturing are cured products of the coating sheet, and the coating sheet has been sufficiently cured.

[0072] The electronic component mounting substrate of the present disclosure comprises the steps of: placing the covering sheet on a substrate on which the electronic component is mounted; forming sealing layers 43, 43a that cover at least a portion of the electronic component and the substrate using the covering sheet; and curing the sealing layers 43, 43a.

[0073] The method for forming the sealing layers 43 and 43a from this coating sheet is not limited, but examples include press molding, the three-dimensional surface coating method TOM (Three-dimensional Overlay Method) molding, vacuum forming, pressure forming, vacuum pressure forming, injection molding, and non-pressure processing. Among these, the non-pressure processing method is particularly suitable for manufacturing this coating sheet.

[0074] The non-pressure processing method for this coating sheet is not particularly limited, but examples include oven heating, hot plate heating, heat gun heating, and spot heating.

[0075] In the step of forming the sealing layers 43 and 43a from the coating sheet, the sealing layers 43 and 43a may be formed by press molding of the coating sheet. The pressure during molding is not particularly limited, but is preferably 0.1 MPa or more and 5 MPa or less. The lower limit is more preferably 0.2 MPa, and particularly preferably 0.3 MPa. The upper limit is more preferably 3 MPa, and even more preferably 2 MPa.

[0076] The processing temperature of the coating sheet is not particularly limited, but any temperature at which the thermal fluid layer of the coating sheet can be thermally melted and cured is acceptable. The temperature is selected according to the composition of the thermal fluid layer of the coating sheet, and is preferably between 100°C and 230°C. The lower limit is more preferably 110°C, and particularly preferably 120°C. The upper limit is more preferably 180°C, even more preferably 160°C, and most preferably 140°C. Within this range, the fluidity of the coating sheet is good, and the coating properties of the sealing layers 43 and 43a on electronic components are good. In addition, the curing of the coating sheet proceeds sufficiently, a strong cross-linked structure can be formed by the sealing layers 43 and 43a, and the strength of the sealing layers 43 and 43a can be improved.

[0077] The time required for the steps of forming the sealing layers 43 and 43a from the coating sheet and curing the sealing layers 43 and 43a is not particularly limited, but is preferably 1 minute or more and 300 minutes or less, more preferably 5 minutes or more and 240 minutes or less, and particularly preferably 10 minutes or more and 180 minutes or less. Within the above range, the electronic component mounting substrate of this disclosure can be manufactured without impairing productivity.

[0078] The sealing layers 43 and 43a consist of an insulating single or multi-layer structure. The sealing layers can be given functions according to needs. For example, they may be given thermal conductivity, waterproofing, shielding, colorability, flame retardancy, hard coating properties, decorative properties, etc. In addition to protecting the exposed surface of the main surface of the substrate 41 with the sealing layer 43, the sides of the substrate 41 may also be protected with the sealing layer 43 as shown in Figure 4. In the examples in Figures 4 and 5, an example in which an electronic component 42 is mounted on one main surface of the substrate 41 is described, but electronic components may be mounted on both main surfaces of the substrate and both main surfaces of the substrate may be covered with the sealing layer.

[0079] Because this mounting substrate uses the electronic component coating sheet described later in this disclosure, the coating sheet exhibits excellent conformability to the electronic components. Furthermore, high dimensional accuracy of the sealing layer can be achieved. Moreover, because the electronic component coating sheet described in this disclosure is particularly suitable for non-pressure processing methods, it can be processed even in the processing of double-sided mounting substrates without distorting the substrate or damaging the chips. [Examples]

[0080] This disclosure will be further described in detail by examples. This disclosure is not limited by these examples. In the examples, "parts" means "parts by mass" and "%" means "percent mass".

[0081] A. Raw materials for electronic component coating sheets, etc. <Thermosetting resin (R)> [Thermosetting resin r1] a. Synthesis of polyester diols In a glass flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and vacuum equipment, 173 parts terephthalic acid, 20 parts adipic acid, 138 parts 3-methyl-1,5-pentanediol, and 16 parts ethylene glycol were charged and stirred while passing nitrogen gas through. The mixture was gradually heated under atmospheric pressure and reacted at 200°C to 230°C for approximately 8 hours to obtain a liquid with an acid value of 41 mg KOH / g. Next, 0.01 parts tetra-n-butoxytitanium was charged, and after purging with nitrogen, the mixture was stirred at 180°C for 30 minutes under a sealed condition. Then, the mixture was reacted at 230°C and 5 mmHg for 2 hours to obtain a polyester diol with an acid value of 1.3 mg KOH / g, a hydroxyl value of 113.5 mg KOH / g, and a molecular weight of 991.

[0082] b. Synthesis of urethane prepolymers Next, 477 parts of the polyester diol, 15.5 parts of dimethylolpropionic acid, 142 parts of tolylene diisocyanate, and 160 parts of toluene were charged into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, and the mixture was reacted at 50°C under a nitrogen atmosphere for 8 hours. To this, 780 parts of toluene were added to obtain a urethane prepolymer solution having isocyanate groups at the ends.

[0083] c. Synthesis of urethane polymers Next, the obtained urethane prepolymer solution was heated to 70°C, and while maintaining this temperature, a solution of 13.0 parts 1,3-diaminopropane, 390 parts 2-propanol, and 625 parts toluene was added dropwise over 1 hour. After the dropwise addition was complete, the reaction was continued at 70°C for a further 6 hours to obtain a polyurethane resin (thermosetting resin r1) with an Mw of 135,000, an acid value of 11.4 mgKOH / g, a Tg of 20°C, and a solids content of 25%.

[0084] [Thermosetting resin r2] In the synthesis of thermosetting resin r1, the amount of dimethylolpropionic acid used in "b. Synthesis of urethane prepolymer" was changed from 15.5 parts to 38.8 parts. Also, the amount of tolylene diisocyanate used was changed from 142 parts to 128 parts. Furthermore, in order to adjust the solid content, the amount of toluene used in "c. Synthesis of urethane prepolymer" was changed from 625 parts to 1300 parts. Except for these changes, the resin was synthesized in the same manner as thermosetting resin a1, and a polyurethane resin (thermosetting resin r2) with Mw of 110,000, Tg of 40°C, and solid content of 21% was obtained.

[0085] <Thermosetting compound (X)> • Thermosetting resin x1:2 functional epoxy compound "Rikaresin HBE-100 (product name)", liquid, melting point -15℃, epoxy equivalent 210g / eq, manufactured by Shin Nippon Rika Co., Ltd. ·Thermosetting resin x2:2 functional epoxy compound "EPICLON N-4050 (product name)", solid, softening point 93℃, epoxy equivalent 900g / eq, manufactured by DIC • Thermosetting resin x3: bifunctional crystalline epoxy compound "YSLV-70XY (product name)", solid form, melting point 77°C, epoxy equivalent 187g / eq, manufactured by Nippon Steel Chemical Co., Ltd. • Thermosetting resin x4: Polyfunctional phenol novolac type epoxy compound "EPICLON N-770 (trade name)", solid, softening point 65°C, epoxy equivalent 180g / eq, manufactured by DIC Corporation.

[0086] <Curing accelerator (C)> • Curing accelerator c1: Imidazole compound "Curezol 2E4MZ (trade name)", solid, melting point 40℃, manufactured by Shikoku Chemicals Co., Ltd. • Curing accelerator c2: Aromatic amine compound "Iharakyuamine(R) MT (trade name)", solid, melting point 98℃, manufactured by Kumiai Chemical Industry Co., Ltd. • Curing accelerator c3: Imidazole compound "Cureazole 2PZ-PW (trade name)", solid, melting point 137℃, manufactured by Shikoku Chemicals Co., Ltd. • Curing accelerator c4: Imidazole compound "Cureazole 2PHZ-PW (trade name)", solid, melting point 230℃, manufactured by Shikoku Chemicals Co., Ltd.

[0087] <Filler (F)> • Filler f1: Carbon Black "Mitsubishi Carbon Black #20 (product name)", D 50 =50nm, manufactured by Mitsubishi Chemical Corporation • Filler f2: Silica "FB-5SDC (product name)", D 50 =4.1μm, manufactured by DENKA Corporation

[0088] B.Measurement method <Weight average molecular weight (Mw)> The Mw of thermosetting resins, etc., is a polystyrene equivalent value obtained by GPC (gel permeation chromatography) measurement. The measurement conditions are as follows: Equipment: Shodex GPC System-21 (manufactured by Showa Denko Corporation) Column: A linked column consisting of one Shodex KF-802 (manufactured by Showa Denko), one Shodex KF-803L (manufactured by Showa Denko), and one Shodex KF-805L (manufactured by Showa Denko) connected in series. Solvent: tetrahydrofuran Flow rate: 1.0mL / min Temperature: 40℃ Sample concentration: 0.2% Sample injection volume: 100 μL

[0089] <Glass transition temperature (Tg)> The glass transition temperature (Tg) of thermosetting resins (R) was measured in accordance with JIS K7198 using a dynamic viscoelasticity analyzer DVA-200 (manufactured by IT Measurement Control Co., Ltd.). For the measurement, a 50 μm thick PET film coated with a silicone release agent was used as the release substrate. The resin was coated onto this release substrate to a thickness of 20 μm using a doctor blade, dried at 100°C for 2 minutes, and the resulting sheet was cut to 0.5 cm × 3 cm. The release substrate was peeled off and used as the sample. Measurements were performed in tensile mode under conditions of strain 0.08%, frequency 10 Hz, heating rate 10°C / min, and temperature range -50 to 300°C. The temperature at which the main dispersion peak of the loss tangent (tanδ) appeared was defined as Tg.

[0090] <Acid value> The acid value (mgKOH / g) was determined by converting the measured value to solid content using a GT-200 automatic titrator manufactured by Mitsubishi Chemical Analytical Corporation, in accordance with the potentiometric titration method specified in JIS K0070.

[0091] C. Fabrication of electronic component covering sheets

[0092] [Example 1] 100 parts of thermosetting resin r1 (solids), 40 parts of curable compound x1 (solids), 1 part of curable compound x1 (solids), 1 part of curing accelerator c3 (Curesol 2PZ-PW), and 1 part of filler f1 were weighed out and placed in a container. Methyl ethyl ketone was then added to the container to a non-volatile content concentration of 30% by mass, and composition A was prepared by stirring with a disperser for 10 minutes. Composition A was coated onto a release film (Y1) using a doctor blade to a thickness of 60 μm after drying. Next, it was dried at 100°C for 4 minutes to obtain a thermofluidized bed (S0) with a release film. (The same procedure was followed in the following examples, etc.).

[0093] The coated surfaces of the obtained release film-coated thermal fluidized layers (S0) were bonded together to produce a release film-coated thermal fluidized layer (S1) with a thickness of 120 μm. Furthermore, after bonding the coated surfaces of the 120 μm-thick thermal fluidized layers together, the release film was peeled off to produce a thermal fluidized layer (S2) with a thickness of 1.08 mm for viscoelasticity evaluation.

[0094] Next, 100 parts of thermosetting resin r1 (solids), 15 parts of curable compound x2 (solids), 3 parts of curing accelerator c3, 1 part of filler f1, and 15 parts of filler f2 were weighed out and placed in a container. Then, toluene was added to the container so that the non-volatile content concentration was 30% by mass, and the mixture was stirred with a disperser for 10 minutes to prepare composition B. Composition B was coated onto a release film (Y2) using a doctor blade so that the thickness after drying was 20 μm. Next, it was dried at 100°C for 4 minutes to obtain a protective layer (S3) with a release film.

[0095] The coated surfaces of the resulting release film-coated protective layers (S3) were bonded together 10 times to create a protective layer (S4) with a thickness of 1.08 mm for viscoelasticity evaluation.

[0096] Next, the coated surfaces of the release film-attached thermal fluid layer (S1) and the release film-attached protective layer (S3) were bonded together, and thermal lamination was performed under the conditions of 90°C, 0.3 MPa, and 1 m / min to obtain a two-layer electronic component coating sheet (S5) with a release film (release film / thermal fluid layer / protective layer / release film).

[0097] [Examples 2-10, Comparative Examples 1-2] Using the same method as in Example 1, only the type and amount of composition were changed as shown in Table 1 to produce release film-coated electronic component coating sheets with laminated structures corresponding to Examples 2-10 and Comparative Examples 1 and 2.

[0098] Table 1 shows the ingredients and their proportions for each example and comparative example. [Table 1]

[0099] D. Rating The following evaluations were performed on the release film-attached electronic component coating sheets and electronic component mounting substrates of each example and comparative example.

[0100] D-1. Evaluation of dynamic viscoelasticity TA Corporation's rheometer "DHR-2" The elastic modulus and complex viscosity of the thermal fluid layer (S2) and protective layer (S4) for viscoelastic evaluation were measured using a viscoelasticity measuring device (TA Instruments, Discovery Hybrid Rheometer series). <Measurement conditions> Plate: Stainless steel plate Top plate diameter: 25mmφ Lower plate diameter: 40mmφ Distortion: 0.1% Frequency: 1.0Hz Load: 5.0N Temperature: 140℃ Time: Heating time 2.2 minutes + holding at 140℃ for 3 hours Heating conditions: 50°C / min

[0101] [Evaluation of elastic modulus] The measurement time was plotted on the x-axis, and the storage modulus (G') and loss modulus (G") were plotted on the y-axis. As shown in Figure 6 as an example, from the obtained data for the storage modulus G' and loss modulus G'', the time when G' was less than G'' was defined as T1, and the time when G' was greater than G'' after T1 was defined as T2, and [T2-T1] (minutes) was calculated. (Figure 6)

[0102] [Evaluation of complex viscosity] The data was plotted with measurement time as the parameter on the horizontal axis (x-axis) and complex viscosity (η) as the parameter on the vertical axis (y-axis). As shown in Figure 7 as an example, the minimum value of the obtained complex viscosity (η) was defined as the minimum melt viscosity (η0), and the time to reach the minimum melt viscosity (η0) was defined as T0 (minutes). (Figure 7) D-2. Evaluation of Gel Fraction

[0103] A 100-mesh wire mesh was cut to a width of 30 mm and a length of 100 mm, and its weight (W1) was measured. Next, the electronic component coating sheets with release films for each example and comparative example were cured at 180°C for 1 hour, then cut to a width of 50 mm and a length of 100 mm, the release films were peeled off, the sheets were folded to a size of 20 mm in width and 20 mm in length, and wrapped in the aforementioned wire mesh to form test specimens. After measuring the weight (W2) of the test specimens, they were immersed in toluene and allowed to penetrate at 25°C for 1 hour. The test specimens were removed from the methyl ethyl ketone and dried at 150°C for 10 minutes, after which their weight (W3) was measured. The weight fraction of the components that remained on the wire mesh without dissolving was calculated as the gel fraction using the following formula [1]. (W3-W1) / (W2-W1)×100 [%] Formula [1]

[0104] As a test substrate, a substrate made of glass cloth epoxy FR-4 (length 80 mm, width 80 mm, height 0.25 mm) was prepared, on which 0603 multilayer ceramic capacitors (MLCCs) (length 0.6 mm, width 0.3 mm, height 0.37 mm) were arranged in an array of 6 x 5 with a mounting spacing of 0.2 mm. Hereinafter, this substrate will be referred to as test substrate (B). D-3. Evaluation of coverage The electronic component coating sheets with release films for each example and comparative example were cut to 5.0 mm vertically and 4.0 mm horizontally, and the release films were peeled off. Next, with the thermal fluid layer side of the electronic component coating sheet facing downwards, it was placed on the MLCC on the test substrate (B) using tweezers. Samples, each with an electronic component coating sheet for an example or comparative example placed on a test substrate (B), were placed in a constant temperature bath (manufactured by ESPEC Corporation) set to 140°C under atmospheric pressure. The electronic component coating sheets were heated for 180 minutes to coat the MLCC area of ​​the test substrate (B). Through these processes, an electronic component mounting substrate coated with a cured electronic component coating sheet was obtained. The obtained electronic component mounting substrate was then evaluated as follows.

[0105] [Coating properties for electronic components] The coating properties of 30 MLCCs on the electronic component-mounted substrates of each example and comparative example were observed using an electron microscope (magnification 400x), and the number of MLCCs with exposed edges or top surfaces was counted and evaluated according to the following criteria. +++: 0 exposed MLCCs (excellent) ++: Number of exposed MLCCs is 1-4 (excellent). +: Number of exposed MLCCs is 5-9 (practical). NG: More than 10 exposed MLCCs (not practical).

[0106] [Coverage between electronic components] The electronic component-mounted substrates of each example and comparative example were polished to form cross-sections in which the spaces between MLCCs could be observed. Next, the presence or absence of voids (air bubbles) between the test substrate and the sealing layer in 10 locations in the central region of the 30 MLCCs arranged in an array was observed and evaluated according to the following criteria. An electron microscope (magnification 400x) was used to confirm the presence of voids. +++: 0 exposed MLCCs (excellent) ++: Number of exposed MLCCs is 1-4 (excellent). +: Number of exposed MLCCs is 5-9 (practical). NG: More than 10 exposed MLCCs (not practical).

[0107] [Dimensional stability] The vertical and horizontal dimensions of the electronic component coating sheet on the electronic component mounting substrate of each example and comparative example were measured, and the maximum dimensional difference was evaluated by comparing it with the electronic component coating sheet before coating (5.0 mm vertical, 4.0 mm horizontal) according to the following criteria. The evaluation method for the dimensional difference was calculated as a negative value if the dimensions after coating were smaller than the dimensions before coating, and a positive value if they were larger. +++: Absolute value of dimensional change is less than 1 mm (excellent) ++: The absolute value of the dimensional change is 1 mm or more and less than 2 mm (excellent). +: Absolute value of dimensional change is 2mm or more and less than 3mm (practical). NG: Dimensional change of 3mm or more in absolute value (not practical).

[0108] [Solvent resistance test] The electronic component mounting substrates coated with the cured electronic component coating sheets of each example and comparative example were immersed in a toluene / IPA = 8 / 2 mixed solvent for 10 minutes. After the solvent dried, the substrates were observed with an electron microscope (magnification 400x), and the number of MLCCs with exposed edges or top surfaces was counted and evaluated according to the following criteria. +++: The number of newly exposed MLCCs is 0 (excellent). ++: The number of newly exposed MLCCs is 1-4 (excellent). +: The number of newly exposed MLCCs is 5-9 (practical). NG: More than 10 newly exposed MLCCs (not practical).

[0109] Comparative Example 2 was deemed unsuitable for evaluation because it was not possible to cover the electronic component mounting substrate with the cured electronic component coating sheet.

[0110] The physical properties and evaluation results of each example and comparative example are shown in Table 2 below.

[0111] [Table 2] [Explanation of Symbols]

[0112] 10 Electronic component covering sheets 11, 21, 31 First layer 22, 32 Second layer 33 Third layer 41 circuit boards 42 Electronic Components 43 Sealing layer 101, 102 Electronic component mounted circuit board

Claims

1. An electronic component covering sheet for forming the sealing layer of an electronic component mounting substrate, comprising a substrate, an electronic component mounted on the substrate, and a sealing layer covering at least a portion of the electronic component and the substrate, The aforementioned electronic component covering sheet has a thermal fluid layer, The aforementioned thermal fluid bed, in dynamic viscoelasticity measurements in accordance with JIS K 7244-10:2005, Measurements were taken under the following temperature profile conditions. The measurement time-storage modulus (G') curve and the measurement time-loss modulus (G'') curve are, It forms two intersection points and has the lowest melt viscosity η ０ An electronic component coating sheet having a pressure of 0.1 Pa·s or more and 500 Pa·s or less. Temperature profile: Heat from 30°C to 140°C at a rate of 50°C / min, then maintain at 140°C for 3 hours.

2. In the dynamic viscoelasticity measurement of the thermal fluid bed, the minimum melt viscosity η ０ Time to reach T ０ Toshi, T ０ The time when the curves of G' and G'' intersect earlier is T. １ , T ０ The time when the curves G' and G'' intersect later is T. ２ In that case, 10 < [T] ２ -T １ <175 points The electronic component coating sheet according to claim 1.

3. Said T ２ The electronic component covering sheet according to claim 2, wherein the time is 180 minutes or less.

4. The electronic component coating sheet according to claim 1, wherein the electronic component coating sheet contains a curing accelerator, the melting point of the curing accelerator is 40°C or higher and 260°C or lower, and contains one or more selected from the group consisting of aromatic amine compounds, imidazole compounds, isocyanate compounds, aziridine compounds, and dicyandiamidoamine compounds.

5. The electronic component coating sheet according to claim 1, wherein the tanδ curve obtained by the dynamic viscoelasticity measurement of the thermal fluid layer has two maximum peaks.

6. The electronic component coating sheet according to claim 1, wherein the maximum value of tanδ obtained by the dynamic viscoelasticity measurement of the thermal fluid layer is 1 or more.

7. The minimum melt viscosity η of the thermal fluid bed at 140°C ０ The electronic component coating sheet according to claim 1, wherein the pressure is 1.0 Pa·s or more and 50 Pa·s or less.

8. The electronic component coating sheet according to claim 1, wherein the process of forming the sealing layer of an electronic component mounting substrate using the electronic component coating sheet is performed under atmospheric pressure in a non-pressure processing manner.

9. An electronic component mounting substrate comprising a substrate, an electronic component mounted on the substrate, and a sealing layer covering at least a portion of the electronic component and the substrate, wherein the sealing layer is formed from a cured product of an electronic component covering sheet according to any one of claims 1 to 8.

10. A method for manufacturing an electronic component mounting substrate, comprising a substrate, an electronic component mounted on the substrate, and a sealing layer covering at least a portion of the electronic component and the substrate, A step of placing an electronic component covering sheet according to any one of claims 1 to 8 on the substrate on which the electronic component is mounted, A step of forming the sealing layer that covers the electronic component and at least a portion of the substrate using the electronic component covering sheet, A method for manufacturing an electronic component mounting substrate, comprising a step of curing the aforementioned sealing layer.

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