Electronic component mounting substrate and electronic equipment

Abstract

Provided is an electronic component mounting substrate that is excellent in adhesion and scratch resistance, is provided, after machining, with a fall prevention layer increasing the smoothness of component corner portions, firmly covers a substrate and an electronic component on the substrate so as to prevent a person's fingernail or another component and the mounted electronic component from catching on each other during a process task such as electronic component mounting, and prevents the electronic component from falling from the substrate due to external damage. The electronic component mounting substrate according to the present disclosure comprises a substrate, an electronic component, and a fall prevention layer. The fall prevention layer that satisfies: (1) a static friction coefficient change rate X of -50% to 200% as obtained using equation 1; and (2) an exponent Y of 0.8 to 20.0 as obtained using equation 2. Equation 1: X = (μk300-μk100) / μk100×100 Equation 2: Y = R2 / (R1+A1)

Description

Electronic component mounting boards and electronic devices

[0001] The present disclosure relates to an electronic component mounting board and an electronic device.

[0002] Terminal electronic devices, including smartphones and wearable devices, are used in a wide variety of environments, requiring high reliability to prevent malfunctions even under harsh conditions. Furthermore, as electronic devices become smaller and thinner, the size of the electronic component mounting boards used is also decreasing, resulting in a reduction in the contact area between the board and the electronic components. This reduces the adhesion between the electronic components and the board, increasing the likelihood of the electronic components falling off the board. This increases the need to prevent breakage or slippage of electronic components due to physical damage, heat, and humidity. Therefore, a method for protecting electronic components, such as IC chips and multilayer ceramic capacitors (MLCCs), from external damage by embedding them in a resin layer is known (see Patent Document 1). However, to reduce the profile of electronic component mounting boards and cut costs, there is a demand for thinner protective layers with reduced post-processing thickness.

[0003] Japanese Patent Application Laid-Open No. 2021-004314

[0004] As mentioned above, inventions relating to coated and protected electronic component mounting substrates have been disclosed. However, when the protective layer is made thinner, many of the problems described below may arise, and there is a demand for an electronic component mounting substrate that can solve all of these problems at once.

[0005] The process of assembling electronic devices involves several steps, including mounting various electronic components onto a substrate using solder or adhesive. After the electronic component-mounted substrate is assembled, it undergoes processes such as assembly into an electronic device and reliability testing. During these processes, electronic components can fall off the substrate or become misaligned due to being caught on a human fingernail or other components. In recent years, electronic components, such as multilayer ceramic capacitors (hereinafter referred to as MLCCs), have rapidly become smaller and thinner. This has resulted in a reduction in the contact area with the substrate, reducing the adhesion between the component and the substrate. This has made it increasingly important to prevent the components from falling off.

[0006] There is also a need for protective materials that are resistant to abrasion and scratches, even when electronic components come into contact with or rub against hard materials such as metals. There is also a need for highly reliable electronic component mounting substrates in which the protective materials do not peel off even when used for long periods in high-temperature, high-humidity environments.

[0007] An object of the present disclosure is to provide a highly reliable electronic component mounting substrate that has excellent abrasion resistance and scratch resistance, is resistant to peeling of electronic components due to external damage, and can be used for a long period of time under high temperature and high humidity conditions, even when the electronic component mounting substrate is miniaturized and has a low profile.

[0008] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by using articles (electronic component mounting substrate, peel-preventing layer, and peel-preventing sheet) having the following characteristics, and have thus completed the present disclosure. That is, the present disclosure relates to an electronic component mounting substrate, peel-preventing layer, and peel-preventing sheet characterized as follows. [1]: An electronic component mounting substrate comprising a substrate, electronic components mounted on at least one surface of the substrate, and a peel-preventing layer covering the substrate and the electronic components, characterized in that the peel-preventing layer satisfies both of the following (1) and (2). (1) The rate of change X of the static friction coefficient calculated by the following [Equation 1] is -50% or more and 200% or less. X=(μk ３００ -μk １００ ) / μ k １００ ×100 [Formula 1] (μk １００ The static friction coefficient of the anti-exfoliation layer after 100 reciprocating abrasion tests, μk ３００ (2) The index Y calculated by the following [Equation 2] is 0.8 or more and 20.0 or less. Y=R ２ / (R １ +A １ ) [Formula 2] (R １ the radius of curvature of the curved surface of the corner of the electronic component in the cross section of the electronic component mounting substrate, R ２ the radius of curvature of the corner of the peel-preventing layer in the cross section of the electronic component mounting substrate, A １; the thickness of the corner of the peel-preventing layer in the cross section of the electronic component mounting substrate) [2]: The peel-preventing layer contains a binder (A) and a filler (B), and the BET specific surface area [m ２ / g] and the content [mass %] of the filler (B) in 100 mass % of the peeling-preventing layer is 0.01 to 15 [mass % m ２ [3]: The thickness A of the peel-preventing layer is 1 / g. ２ [4]: An electronic device equipped with the electronic component mounting substrate according to any one of [1] to [3].

[0009] The present disclosure makes it possible to provide an electronic component mounting board that is miniaturized and has a low profile, but that prevents electronic components from falling off due to external damage over a long period of time, and an electronic device that mounts such an electronic component mounting board.

[0010] 1 is a schematic cross-sectional view of an electronic component mounting board according to an embodiment of the present invention; １ , R ２ , A １ Fig. 1 is a schematic cross-sectional view of an electronic component mounting substrate according to an embodiment of the present invention, clearly showing the above-mentioned. Fig. 2 is a diagram showing a part of a flow of a manufacturing process of an electronic component mounting substrate according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view showing an example of an electronic component mounting substrate according to an embodiment of the present invention. Fig. 4 is a diagram showing an evaluation method of an electronic component mounting substrate according to an example.

[0011] The present disclosure will be described below through embodiments of the present invention, but the following embodiments do not limit the scope of the invention as claimed. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0012] 1, an electronic component mounting substrate 10 according to the present disclosure includes a substrate 1, an electronic component 2 mounted on the substrate 1, and a peel-preventing layer 3 that covers and protects the substrate 1 and the electronic component 2. The substrate 1 or the electronic component 2 has a region containing a resin component (not shown), and the peel-preventing layer 3 covers the surface thereof.

[0013] The substrate 1 can be selected arbitrarily as long as it can mount the electronic component 2 and can withstand the molding process for each application. The substrate 1 can be provided with any electrode / wiring pattern, vias (not shown), etc. The substrate 1 may be rigid or flexible. Examples of the substrate 1 include a work board on the surface and / or inside of which a conductive pattern made of copper foil or the like is formed, a mounting module board, a printed wiring board, and a build-up board formed by a build-up method or the like.

[0014] Examples of the electronic component 2 include connectors, film capacitors, components formed by molding wafers or wires such as IC chips, inductors, thermistors, MLCCs, coils, diodes, electrolytic capacitors, and quartz crystal oscillators. Among these, MLCCs and IC chips are preferably applied as the electronic component 2 to the present disclosure, since they are becoming increasingly smaller.

[0015] When a plurality of electronic components 2 are mounted, the shapes and heights of the respective electronic components 2 may be the same or different.

[0016] The size and height of the electronic component 2 are not particularly limited, but a height of 3 mm or less is preferable in light of the recent trend toward miniaturization and low profile. The IC chip may be rectangular, cylindrical, coin-shaped, thin-film, or other shapes. The MLCC is preferably in the mainstream package sizes of 0402 (length 0.4 mm, width 0.2 mm) or 0603 (length 0.6 mm, width 0.3 mm), but larger sizes such as 1005 and 1608 may also be mounted. The inductor shapes include sono-laid, dome-shaped coils, flat coils, and the like. Thermistors include surface-mount rectangular, cylindrical, and lead-type types.

[0017] The electronic component 2 may be electrically connected to the substrate via solder bumps 4, or the substrate may be directly connected to connection terminals extending from the electronic component. When the electronic component 2 is connected to the substrate 1 via solder bumps 4, a hollow space 5 is created between the electronic component 2 and the substrate 1, as shown in FIG.

[0018] The anti-peeling layer 3 may cover and protect the electronic component 2 and the substrate 1 while maintaining the hollow portion 5, or may cover and protect the hollow portion 5 so as to fill it. The anti-peeling layer 3 can be produced by the method described below.

[0019] The anti-peeling layer 3 covers the substrate 1 and the electronic components 2. In FIG. 1 , the anti-peeling layer 3 covers the top and side surfaces of the electronic components 2, and also the entire surface or a portion of the edge surface of the substrate 1. In other words, a coating layer (anti-peeling layer 3) is provided that conforms to the steps (uneven portions) formed by the mounting of the electronic components 2. The anti-peeling layer 3 is formed using an anti-peeling sheet (reference numeral 6 in FIG. 3 ), which is a precursor of the anti-peeling layer 3. The method for forming the anti-peeling layer 3 from the anti-peeling sheet 6 is not limited, but any one of press molding, a three-dimensional surface coating method called TOM (Three Dimension Overlay Method) molding, vacuum molding, pressure molding, vacuum pressure molding, and injection molding is preferred. Among these, press molding is particularly preferred as a method for forming the anti-peeling layer 3 from the anti-peeling sheet 6.

[0020] 1 has been described as an example in which electronic components 2 are mounted on one surface of substrate 1, but electronic components 2 may be mounted on both surfaces of substrate 1, and both surfaces of substrate 1 may be covered with anti-peeling layer 3. In this way, in the electronic component-mounted substrate according to the present disclosure, electronic components 2 are mounted on at least one surface of substrate 1, and anti-peeling layer 3 is provided to cover substrate 1 and these electronic components 2.

[0021] Next, the peeling-preventing layer in the present disclosure will be described in more detail. As described above, the peeling-preventing layer 3 is intended to prevent the electronic components 2 arranged on the substrate 1 from peeling off from the mounting substrate 1.

[0022] The anti-exfoliation layer 3 satisfies both of the following (1) and (2): (1) The rate of change X of the static friction coefficient calculated by the following [Equation 1] is -50% or more and 200% or less. (2) The index Y calculated by the following [Equation 2] is 0.8 or more and 20.0 or less. These numerical values ​​X and Y are values ​​calculated by the following [Equation 1] and [Equation 2], and X and Y are measured according to the methods and conditions described in the examples below.

[0023] <<Rate of change X of static friction coefficient>> The rate of change X of the static friction coefficient obtained by the reciprocating abrasion test of the anti-exfoliation layer (hereinafter referred to as the rate of change X of the static friction coefficient) can be expressed by the following [Equation 1]: X=(μk ３００ -μk １００ ) / μ k １００ ×100 [Formula 1]

[0024] Here, μ １００ is the static friction coefficient of the anti-exfoliation layer after 100 reciprocating abrasion tests, and μk ３００ is the static friction coefficient of the anti-exfoliation layer after 300 reciprocating abrasion tests. １００ , μ ３００ The method for measuring is described in detail in the Examples.

[0025] The rate of change X of the static friction coefficient is measured using an abrasion tester. The number of times when the static friction coefficient stabilizes during measurement is compared with the number of times that serves as the standard for determining whether or not there is wear resistance. １００ and the static friction coefficient μk at 300 times, which is an index of wear resistance. ３００ The rate of change X of the static friction coefficient is an index for determining whether a constant static friction coefficient is maintained when the reciprocating abrasion test is continued, i.e., whether the coefficient of change X of the static friction coefficient is abrasion resistance. A positive rate of change X of the static friction coefficient indicates the progression of abrasion, with larger values ​​indicating lower abrasion resistance. A negative rate indicates less abrasion and increased slippage on the surface of the anti-exfoliation layer, which is thought to be due to the influence of fillers exposed when the film surface is scraped, wear powder on the surface of the anti-exfoliation layer, and frictional heat.

[0026] In order to obtain stable measurements, the abrasion test is performed on the smooth surface of the anti-peeling layer formed on the resin-containing region of the electronic component or substrate. The resin region refers to the portion of the surface of the mold resin, glass epoxy resin, or the like that is covered with resin.

[0027] In the present disclosure, the rate of change X of the static friction coefficient is -50% or more and 200% or less, thereby improving the abrasion resistance of the peel-preventing layer on the electronic component mounting substrate. X is preferably -25% or more and 150% or less, and more preferably -5% or more and 100% or less. By setting the rate of change X on the peel-preventing layer within the above range, the peel-preventing layer becomes less susceptible to scratches, and the abrasion resistance and scratch resistance are improved.

[0028] [Control Method] Any method can be applied to control the rate of change X of the static friction coefficient of the anti-exfoliation layer, including conventionally known methods. For example, there are methods such as improving resistance to friction by hardening the surface of the anti-exfoliation layer by adjusting the compounding components added to the anti-exfoliation layer, adding wax components or the like to the anti-exfoliation layer to improve the slipperiness of the oil-retaining surface, reducing surface irregularities by reducing the amount of added particulate components or changing the shape (reducing the surface friction coefficient), increasing the heat resistance of the anti-exfoliation layer, and reducing surface irregularities by changing the type of protective film used when forming an anti-exfoliation sheet that serves as a precursor to the anti-exfoliation layer on an electronic component-mounted substrate. Methods for controlling the abrasion resistance of the anti-exfoliation layer surface are not limited to the exemplified methods, but methods such as increasing the amount of curing agent in the anti-exfoliation layer to harden the surface or adjusting the amount and shape of particulate matter in the anti-exfoliation layer to reduce surface irregularities are preferred from the standpoint of productivity, as they eliminate the need for pre- and post-treatment.

[0029] <<Index Y>> The peel-preventing layer in the present disclosure has an index Y of 0.8 or more and 20.0 or less, as calculated by the following [Equation 2]. By setting the index Y in the above numerical range, an appropriate shape can be obtained that smoothly covers the surface of the electronic component mounting substrate and prevents the electronic components from peeling off. From the viewpoint of ensuring uniformity in the thickness of the peel-preventing layer (ability to conform to the components) and the thickness of the corners of the electronic components, Y is preferably 0.9 or more and 12.0 or less, and more preferably 1.0 or more and 5.0 or less. Y=R ２ / (R１ +A １ ) [Formula 2] Note that R in [Formula 2] ２ , R １ , A １ is obtained from the measurement value of the cross section of the electronic component mounting substrate 11 shown in FIG. 2 taken perpendicular to the substrate surface, and the radius of curvature of the curved surface of the corner of the electronic component 2 in the cross section of the electronic component mounting substrate 11 is R １ The radius of curvature of the corner of the peel-off preventing layer 3 in the cross section of the electronic component mounting substrate 11 mounted thereon is R ２ , the thickness of the corner of the peeling prevention layer 3 in the cross section of the electronic component mounting substrate 11 is A １ (Hereinafter, the corner thickness A of the peel-preventing layer １ The cross section of the electronic component mounting substrate 11 is cut out by dicing or polishing, and the cross section is measured by a digital microscope VHX-7000 (manufactured by Keyence Corporation) to obtain the R ２ , R １ , A １ It is possible to obtain the radius of curvature R １ and R ２ indicates the point at each corner where catching is most likely to occur, and refers to the radius of curvature that is the smallest value when measured at each corner.

[0030] The index Y is a value that represents the change in smoothness between the corners of the electronic component 2 and the corners of the anti-peeling layer 3 on the electronic component. By setting the index Y within the above range, it is possible to prevent the electronic component 2 from peeling off due to the electronic component 2 getting caught on a nail or another component, which can occur during inspection of the electronic component mounting board 11 or when the electronic component mounting board 11 is mounted on an electronic device in a later process.

[0031] The index Y can be controlled by adjusting the conformability and fluidity of the anti-peeling sheet 6 to the electronic components 2 during processing. Specifically, examples include a method of adjusting by selecting the binder (A) and filler (B) constituting the anti-peeling sheet 6 described below, a method of adjusting the conformability of the anti-peeling sheet 6 to the substrate 1 and electronic components 2 by adjusting the processing conditions (processing temperature, processing time, pressure conditions, vacuum degree, etc.) during processing of the anti-peeling sheet 6, and a method of controlling the fluidity of the anti-peeling sheet 6 by changing the layer configuration during processing of the anti-peeling sheet 6. When multiple anti-peeling sheets 6 are used, different methods can be applied to each of them, or a common method can be applied.

[0032] <<Binder (A)>> The anti-exfoliation layer 3 contains a binder (A). The binder (A) serves as a base for the anti-exfoliation layer and has the function of supporting the filler (B) described below and other optional components. The binder (A) can be either a thermoplastic resin, or a thermosetting resin and a curable compound.

[0033] [Thermoplastic resin] Examples of thermoplastic resins include polyolefin resins, vinyl resins, styrene-acrylic resins, diene resins, terpene resins, petroleum resins, cellulose resins, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, and fluororesins. Although not particularly limited, from the viewpoint of heat resistance, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, and fluororesins are more preferred. The thermoplastic resins can be used alone or in combination of two or more.

[0034] [Thermosetting Resin] The thermosetting resin is a resin having multiple functional groups capable of reacting with a curable compound. Examples of functional groups include hydroxyl groups, phenolic hydroxyl groups, acid anhydride groups, methoxymethyl groups, carboxyl groups, amino groups, epoxy groups, oxetanyl groups, oxazoline groups, oxazine groups, aziridine groups, thiol groups, isocyanate groups, blocked isocyanate groups, blocked carboxyl groups, and silanol groups. Examples of thermosetting resins include known resins such as acrylic resins, maleic acid resins, polybutadiene-based resins, polyester resins, polyurethane resins, polyurethane urea resins, epoxy resins, oxetane resins, phenoxy resins, polyimide resins, polyamide resins, polyamideimide resins, phenolic resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, and fluororesins. The thermosetting resins can be used alone or in combination of two or more.

[0035] Among these, from the viewpoint of heat resistance, preferred thermosetting resins are polyurethane resin, polyurethane urea resin, polyester resin, epoxy resin, phenoxy resin, polyimide resin, polyamide resin, and polyamideimide resin.

[0036] [Curable Compound] The curable compound has a plurality of functional groups capable of reacting with the functional groups of the thermosetting resin. Examples of the curable compound include known compounds such as epoxy compounds, acid anhydride group-containing compounds, isocyanate compounds, aziridine compounds, amine compounds, phenolic compounds, and organometallic compounds. The curable compounds can be used alone or in combination of two or more.

[0037] The curable compound is preferably bifunctional or more, and more preferably contains a trifunctional or more curable compound. From the viewpoint of adjusting the crosslink density and achieving both the processability during molding of the electronic component-mounted substrate described below and the stability over time of the composition that is the precursor of the peel-preventing sheet, it is desirable to use a bifunctional curable compound in combination with a trifunctional or more curable compound. By adjusting the content of the curable compound as described below, a strong crosslinked structure is formed in the peel-preventing layer, thereby increasing the adhesion between the peel-preventing layer and the substrate and improving reliability. In this way, the adhesion between the peel-preventing layer and the substrate can also be adjusted by the content of the curable compound in the composition.

[0038] The bifunctional curable compound is preferably contained in an amount of 1 to 50 parts by mass, more preferably 15 to 30 parts by mass, per 100 parts by mass of the thermosetting resin. By increasing the amount of the bifunctional curable compound to 1 part by mass or more, a stronger crosslinked structure is formed in the anti-exfoliation layer, further improving resistance to thermal damage. Furthermore, by increasing the amount of the bifunctional curable compound to 15 parts by mass or more, the hardness and strength of the surface of the anti-exfoliation layer can be adjusted, further improving abrasion resistance. On the other hand, by increasing the amount of the curable compound to 50 parts by mass or less, excessive curing of the anti-exfoliation layer can be easily suppressed, and cracking due to shrinkage after curing of the anti-exfoliation sheet can be easily suppressed.

[0039] The trifunctional or higher curable compound is preferably contained in an amount of 0.2 to 20 parts by mass, more preferably 0.3 to 5 parts by mass, and even more preferably 0.8 to 3 parts by mass, per 100 parts by mass of the thermosetting resin. When the amount of the trifunctional or higher curable compound is 0.2 parts by mass or more, the adhesion between the anti-peeling layer and the substrate is further improved, thereby further improving reliability. Furthermore, when the amount of the trifunctional or higher curable compound is 20 parts by mass or less, the anti-peeling sheet 6 can be easily deformed to conform to the shape of the electronic components 2 during heating and pressure application in the manufacturing process of the electronic component mounting substrate described below, thereby easily forming a defect-free anti-peeling layer.

[0040] [Lubricant] The anti-exfoliation layer 3 may contain a lubricant such as wax. By adding such a lubricant, the slipperiness of the anti-exfoliation layer surface is increased, and abrasion resistance can be easily improved. Further improvement in reliability can be expected by making the anti-exfoliation layer surface less susceptible to cracking. Examples of waxes include animal and plant waxes such as beeswax, lanolin wax, spermaceti, candelilla wax, carnauba wax, rice wax, Japan wax, jojoba oil, and palm oil; mineral and petroleum waxes such as montan wax, ozogellite, ceresin, paraffin wax, microcrystalline wax, and petrolatum; and synthetic waxes such as Fischer-Tropsch wax, polyethylene wax, oxidized polyethylene wax, oxidized polypropylene wax, montan wax derivatives, paraffin wax derivatives, microcrystalline wax derivatives, and Teflon (registered trademark) wax.

[0041] <<Filler (B)>> The anti-exfoliation layer 3 contains a filler (B). By appropriately changing the type, average particle size, and amount of filler (B), the index Y and the rate of change X of the static friction coefficient can be controlled. Furthermore, by adjusting the cohesive force in the anti-exfoliation layer 3, mechanical properties such as the maximum point stress T can be kept within a favorable range. When insulation is required, an insulating filler is used; when conductivity is required, a conductive filler is used; and when electromagnetic wave absorption is required, an electromagnetic wave absorbing filler is used. The shape of the filler can be selected appropriately. Examples include flake-shaped, acicular, spherical, dendritic, and fibrous fillers. Fillers of different shapes may be used in combination. Suitable examples include a combination of spherical fillers with average particle sizes that differ by 10 times or more, or a combination of a flake-shaped filler and a dendritic filler.

[0042] Examples of the insulating filler include non-metallic inorganic fillers such as silica, alumina, boron nitride, aluminum nitride, magnesium silicon nitride, silicon carbide, titania, glass, ceramic, etc. The insulating filler may be used alone or in combination of two or more.

[0043] Examples of conductive fillers include metal fillers, conductive ceramic fillers, and mixtures thereof. Examples of metal fillers include metal powders such as gold, silver, copper, and nickel, alloy powders such as solder, and core-shell fillers such as silver-coated copper powder, gold-coated copper powder, silver-coated nickel powder, and gold-coated nickel powder. From the viewpoint of obtaining excellent conductive properties, conductive fillers containing silver are preferred. From the viewpoint of cost, silver-coated copper powder is particularly preferred.

[0044] Examples of the electromagnetic wave absorbing filler include iron alloys such as iron, Fe—Ni alloys, Fe—Co alloys, Fe—Cr alloys, Fe—Si alloys, Fe—Al alloys, Fe—Cr—Si alloys, Fe—Cr—Al alloys, and Fe—Si—Al alloys, ferrite-based substances such as Mg—Zn ferrite, Mn—Zn ferrite, Mn—Mg ferrite, Cu—Zn ferrite, Mg—Mn—Sr ferrite, and Ni—Zn ferrite, and carbon fillers. Examples of the carbon filler include acetylene black, ketjen black, furnace black, carbon black, carbon fiber, fillers made of carbon nanotubes, graphene fillers, graphite fillers, and carbon nanowalls.

[0045] The average particle size of the filler (B) is preferably 0.005 to 50 μm, and more preferably 0.02 to 20 μm from the viewpoints of maintaining the smoothness of the anti-exfoliation layer surface, reducing the influence of abrasion powder during abrasion, and improving abrasion resistance.

[0046] The content of the filler (B) in 100% by mass of the anti-exfoliation layer is preferably 0.1 to 80% by mass, and from the viewpoint of improving the surface characteristics and improving scratch resistance while suppressing the fall-off of the filler (B) from the surface of the anti-exfoliation layer, it is more preferably 1.0 to 35% by mass. When the content of the filler (B) is 80% by mass or less, the abrasion resistance is further improved.

[0047] BET specific surface area [m ２The product of [g / g] and the content [mass%] of the filler (B) in 100 mass% of the anti-peeling layer (hereinafter referred to as the product of specific surface area and content) is preferably 0.01 to 15, more preferably 0.1 to 10. When two or more types of filler (B) are used, this product of specific surface area and content is the sum of the products of the specific surface area and content required for the various fillers (B) contained in the anti-peeling layer. When the product of specific surface area and content is within the above range, the filler (B) acts as a reinforcing material in the anti-peeling sheet, thereby easily preventing breakage of the anti-peeling sheet 6 during heating and pressurization in the manufacturing process of the electronic component mounting board described below, and easily forming a defect-free anti-peeling layer. Furthermore, when the product of specific surface area and content is 15 or less, the adhesion of the anti-peeling layer to the substrate and electronic components is further ensured, thereby easily optimizing scratch resistance and anti-peeling properties.

[0048] BET specific surface area [m ２ / g] is preferably 0.1 to 150.

[0049] The anti-peeling sheet 6 may contain a flexibility adjuster. The flexibility adjuster can easily prevent wrinkling and tearing during molding of the anti-peeling sheet 6. Examples of the flexibility adjuster include a plasticizer and an inactive thermoplastic resin that is chemically unreactive itself.

[0050] Examples of the plasticizer include fatty acid esters, phthalate esters, aromatic polycarboxylic acid esters, and polyesters. Examples of fatty acid esters include trioctyl trimellitate (TOTM), manufactured by Mitsubishi Gas Chemical Trading Co., Ltd., butyl stearate, Unistar M-9676, Unistar M-2222SL, Unistar H-476, Unistar H-476D, Panasate 800B, Panasate 875, and Panasate 810 (all trade names, manufactured by NOF Corp.), DBA, DIBA, DBS, DOA, DINA, DIDA, DOS, BXA, DOZ, and DESU (all trade names, manufactured by Daihachi Chemical Industry Co., Ltd.). Examples of phthalate esters include DMP, DEP, DBP, #10, BBP, DOP, DINP, and DIDP (all trade names, manufactured by Daihachi Chemical Industry Co., Ltd.), PL-200 and DOIP (all trade names, manufactured by C.G. Ester Co., Ltd.), and Sanso Cizer DUP (trade name, manufactured by New Japan Chemical Co., Ltd.). Examples of aromatic polycarboxylic acid esters include TOTM (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.), Monocizer W-705 (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.), UL-80 and UL-100 (all trade names, manufactured by ADEKA Corporation). Examples of polyesters include Polycizer TD-1720, Polycizer S-2002, and Polycizer S-2010 (all trade names, manufactured by DIC Corporation), and BAA-15 (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.). Of these, DMP, DEP, DBP, DOP, DINP, DIDP, and TOTM (all trade names) are more preferred. The plasticizers may be used alone or in combination of two or more.

[0051] Examples of the inactive thermoplastic resin include polyolefin resins, vinyl resins, styrene-acrylic resins, diene resins, terpene resins, petroleum resins, cellulose resins, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, and fluororesins. Although not particularly limited, from the viewpoint of heat resistance, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, and fluororesins are more preferred as the inactive thermoplastic resin.

[0052] Furthermore, the anti-peeling sheet 6 may contain a tackifying resin to improve adhesion to the substrate 1 and the electronic component 2. A tackifying resin is a component that supplementarily improves adhesive strength, has a weight-average molecular weight of less than 5,000, and is distinguished from the thermoplastic resin and binder described above. Examples of tackifying resins include rosin-based resins, terpene-based resins, alicyclic petroleum resins, and aromatic petroleum resins.

[0053] The anti-peeling sheet 6 may further contain colorants, UV colorants, flame retardants, lubricants, anti-blocking agents, etc. Examples of colorants include organic pigments, carbon black, ultramarine, red iron oxide, zinc oxide, titanium oxide, graphite, and dyes. Examples of UV colorants include fluorescent pigments, fluorescent dyes, and phosphorus. 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, polymethylsilsesquioxane, and aluminum silicate. Furthermore, one or more of these additives may be used in combination.

[0054] <<Thickness A of anti-peeling layer>> ２ Thickness A of anti-peeling layer 3 ２ The thickness A is preferably 5 to 300 μm from the viewpoint of achieving both the anti-peeling property (wear resistance and scratch resistance) of the electronic component 2 and thinning, and more preferably 15 to 200 μm. ２ is the measured value of the thickest portion formed in the upper surface region of the electronic component 2 in the cross-sectional image of the electronic component 2.

[0055] <<Maximum Point Stress T of Peel-Preventing Layer>> The maximum point stress T of the peel-preventing layer 3 is a value obtained in a tensile test in accordance with JIS K 7162. Specifically, it is the maximum stress T when a peel-preventing layer with an effective tensile size of 20 × 23 mm is pulled at 50 mm / min in an atmosphere of 100°C (air, 50% RH). The maximum point stress T is preferably 1 MPa or more and 100 MPa or less, and more preferably 15 MPa or more and 40 MPa or less. When the maximum point stress T is 1 MPa or more, abrasion resistance and scratch resistance can be further improved. On the other hand, when the maximum point stress T is 100 MPa or less, the conformability of the peel-preventing sheet 6 to the electronic component 2 is further improved when the peel-preventing layer is formed on the electronic component. Furthermore, it is possible to easily suppress defects in appearance and processing, such as the occurrence of gaps between the anti-peeling layer 3 and the substrate 1 or between the anti-peeling layer 3 and the electronic component 2, or the occurrence of breakage or cracks in the anti-peeling layer 3, which can lead to peeling of the electronic component 2 or breakage of the anti-peeling layer 3 at the corners.

[0056] The maximum point stress T of the anti-peeling layer 3 can be adjusted, for example, by selecting a thermoplastic resin or a thermosetting resin, the crosslink density in the anti-peeling layer, and the filler. Regarding the crosslink density, a method of adjusting the number of functional groups and the equivalent weight of the curable compound in the composition for forming the anti-peeling layer is preferred. Regarding the selection of the filler, the selection can be made based on factors such as the material, shape, size, surface condition, specific surface area, and amount added of the filler, but it is preferred to select the filler taking into consideration the specific surface area and amount added.

[0057] <<Tg of Anti-Peeling Layer>> The Tg of the anti-peeling layer 3 is a value measured using a dynamic viscoelasticity measuring device. If multiple Tgs of the anti-peeling layer are confirmed, the highest value of tan δ is used. The Tg of the anti-peeling layer 3 is preferably 5°C or higher and 180°C or lower, more preferably 20°C or higher and 80°C or lower. By adjusting the fluidity of the anti-peeling layer by setting the Tg at 5°C or higher and 180°C or lower, the anti-peeling layer can be easily processed into an optimal shape, and the index Y can be easily adjusted to an optimal range. Furthermore, by setting the Tg at 20°C or higher and 80°C or lower, resistance to frictional heat due to wear and thermal damage during inspection in subsequent processes can be easily achieved, further improving reliability. When the binder (A) contains a thermosetting resin, the maximum point stress T and Tg refer to those after heat curing.

[0058] <<Peeling-Preventing Sheet>> As shown in Fig. 3 , the peeling-preventing sheet 6 is a precursor of the peeling-preventing layer 3. When the peeling-preventing sheet 6 contains a thermosetting resin, the peeling-preventing sheet 6 is heated at a temperature for a predetermined time or longer to cause a curing reaction, thereby forming the peeling-preventing layer 3. The peeling-preventing sheet 6 may be provided with a release sheet on one or both sides for surface protection. Furthermore, the cushioning material 7 used in the coating and protection step with the peeling-preventing sheet 6 described below may be laminated in advance.

[0059] <<Method for Producing Exfoliation-Preventing Sheet>> The method for producing the exfoliation-preventing sheet 6 is not particularly limited, and examples thereof include a method of applying a composition obtained by dissolving a material such as the binder (A) that forms the exfoliation-preventing layer 3 in a solvent or the like to a release sheet. Examples of the application method 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.

[0060] The anti-peeling sheet 6 of the present disclosure may be formed by laminating two or more anti-peeling sheets to achieve a desired thickness. As described above, the laminated structure may consist of only anti-peeling sheets, or may include a layer having a specific function as an intermediate layer.

[0061] <<Uses of Anti-Peeling Sheet>> The anti-peeling sheet 6 of the present disclosure can be suitably used to protect various substrates 1, i.e., various substrates such as rigid substrates and FPC substrates, and electronic components 2 mounted thereon. Furthermore, the anti-peeling sheet 6 of the present disclosure exhibits practically sufficient adhesion strength regardless of whether the substrate 1 is made of metal, resin, fiber, ceramic, glass, or conductive silicone. Examples of metals that can be used include aluminum, copper, brass, stainless steel, iron, and chromium. Examples of resins that can be used include epoxy resin, polyethylene terephthalate, polyimide, polyamide, polyethylene, polypropylene, polyolefin graft polymer, polystyrene, and polyvinyl chloride. Thus, the anti-peeling sheet 6 can also be suitably used to bond different materials with different polarities.

[0062] <<Method for Manufacturing Electronic Component Mounting Substrate>> A method for manufacturing an electronic component mounting substrate will be described. The method for manufacturing an electronic component mounting substrate according to the present disclosure includes the steps of mounting one or more electronic components 2 on a substrate 1 (step i), preparing a peel-preventing sheet 6 (step ii), placing the peel-preventing sheet 6 so that it contacts the tallest electronic component among the electronic components 2 (step iii, also referred to as a temporary attachment step), deforming the peel-preventing sheet 6 by applying heat and pressure to conform to the shapes of the individual electronic components 2 and cover at least a portion of the electronic components 2 and the substrate 1 (step iv), and curing the deformed peel-preventing sheet 6 in its deformed state to form a peel-preventing layer 3 (step v). These steps allow the electronic component mounting substrate to be covered and protected by the peel-preventing layer 3 formed from the peel-preventing sheet 6 according to the present disclosure. Note that steps iv and v can be performed in a single process.

[0063] An example of a method for covering and protecting an electronic component mounting substrate by applying heat and pressure using a peel-preventing sheet 6 will be described below with reference to FIG. 3 for steps iii to v.

[0064] (Step iii: Anti-peeling sheet placement step) A mounting substrate 100 is prepared, in which electronic components 2 are mounted on a substrate 1 directly or via solder bumps 4. The electronic components 2 may be semiconductor chips, capacitors, transistors, inductors, thermistors, etc., and may be mounted on the substrate 1 via solder bumps 4, or there may be a gap between the electronic components 2 and the substrate 1. The electronic components 2 may also have different heights. Next, an anti-peeling sheet 6 cut to a predetermined size is placed on the mounting surface of the electronic components 2. The anti-peeling sheet 6 comes into contact with the taller electronic components 2 and is temporarily attached. Note that the anti-peeling sheet 6 may bend and come into contact with other electronic components 2 (not shown in Figure 3).

[0065] A cushioning material 7 may be laminated on the anti-peeling sheet 6. Figure 3 shows an example using a cushioning material 7. The cushioning material 7 may be laminated after the anti-peeling sheet 6 is placed, or a laminate of the anti-peeling sheet 6 and the cushioning material 7 may be placed first. The cushioning material 7 is a material that softens or melts when heated and pressurized, and functions to facilitate the conformability of the anti-peeling sheet 6 to the electronic components 2 and to the gaps between the electronic components 2. The cushioning material 7 is not particularly limited as long as it is a thermoplastic material, but it preferably has a melting temperature and glass transition point (Tg) lower than the temperature at which pressure is applied. Suitable examples of the cushioning material 7 include polyolefin films, vinyl chloride films, and PVA films. Depending on the depth of the groove, the thickness of the cushioning material 7 is typically approximately 100 μm to 1 mm. When multiple cushioning materials 7 are laminated, it is preferable that their total thickness be within this range.

[0066] The electronic component mounting board according to the present disclosure is merely an example, and the structures of the electronic components and the board are not particularly limited, and there may or may not be a gap between the electronic components 2 and the board 1. The position of the mounted electronic components 2 is not limited.

[0067] (Step iv: Step of covering at least a portion of the electronic components and the substrate) Next, heating and pressing are performed using a heating and pressing machine 20, whereby the anti-peeling sheet 6 is deformed to conform to the shapes of the individual electronic components 2, i.e., to conform to the top and side surfaces of the electronic components 2, and to conform to at least a portion of the electronic components and the substrate 1. The cushion material 7 softens or melts due to heat, promoting conformation of the anti-peeling sheet 6 to the irregularities between the electronic components on the mounting substrate 100. It is also preferable to use a method in which a release sheet (not shown) is interposed between the heating and pressing machine 20 and the cushion material 7 during heating and pressing. The release sheet is a sheet obtained by subjecting a base material such as paper or plastic to a known release treatment. Alternatively, a plastic sheet with low polarity such as Teflon (registered trademark) can be used.

[0068] The heating temperature should be such that the anti-peeling sheet 6 softens appropriately, conforms to the shape of the individual electronic components 2, deforms, and penetrates into the gaps between the individual electronic components. It is preferably 100 to 260°C, and more preferably 120 to 240°C. A heating temperature of 100°C or higher easily prevents a decrease in the ability of the anti-peeling sheet 6 to penetrate into the gaps between the individual mounted electronic components. On the other hand, a heating temperature of 260°C or lower easily prevents a decrease in the ability of the anti-peeling sheet 6 to penetrate into the gaps between the mounted electronic components due to the rapid thermosetting reaction of the thermosetting resin in the anti-peeling sheet 6. The pressure when applying heat and pressure is preferably 0.01 to 15 MPa, more preferably 0.1 to 6.0 MPa. Applying heat and pressure within the above pressure range improves embeddability without damaging the electronic components. The heating time is typically 0.5 to 30 minutes, preferably 1 to 20 minutes. A heating time of 0.5 minutes or more can easily prevent a decrease in the penetration of the anti-peeling sheet 6 between the mounted electronic components. On the other hand, a heating time of 30 minutes or less can easily prevent the thermosetting resin from thermally decomposing or oxidizing, which can easily prevent an increase in the possibility of a decrease in the reliability of the adhesive portion due to reaction products, etc. The heating and pressing step is preferably carried out in a vacuum. As a heating and pressing method, in addition to using a heating and pressing machine, a method in which metal plates of appropriate weight are stacked to achieve a predetermined pressure and the stack is then placed in an oven is also preferred. On the other hand, vacuum forming or vacuum-pressure forming is also preferred as a heating and pressing method other than using a heating and pressing machine.

[0069] (Step v: Step of curing the deformed peel-preventing sheet) When the peel-preventing sheet 6 contains a thermosetting resin, after heating and pressurizing, the peel-preventing sheet 6 is further heated in its deformed state at a temperature of 150°C to 230°C for 10 to 60 minutes to thermally cure the thermosetting resin in the peel-preventing sheet 6 and form the peel-preventing layer 3. The peel-preventing layer 3 firmly bonds to the electronic component 2 and the substrate 1, and functions as the peel-preventing layer 3 for preventing and protecting the electronic component 2 from damage due to external impact or abrasion. Note that in the stage of (Step iv), for example, the heat-preventing temperature can be set to 150°C or higher for a time of 30 minutes or longer, thereby completing the thermal curing and forming the peel-preventing layer 3.

[0070] In the electronic component mounting substrate according to the present disclosure, the peel-preventing layer is preferably the outermost layer. Furthermore, other functional layers may be laminated on the inner layer side. Examples of other functional layers include layers having electrical conductivity, hard coating properties, water vapor barrier properties, oxygen barrier properties, thermal conductivity, low dielectric constant, high dielectric constant, and heat resistance. In particular, functional layers having electrical conductivity may be used to protect the electronic components they cover from electromagnetic noise.

[0071] 4 shows an example of the configuration of an electronic component mounting substrate 12 having a conductive functional layer 8 on the peel-preventing layer 3. The conductive functional layer 8 is formed on the upper side (upper layer) of the peel-preventing layer 3 as viewed in the drawing, and is connected to ground 9. The connection point with ground 9 may be on the surface of the substrate 1 or on a side surface of the substrate 1. The conductive functional layer 8 can be formed by forming a metal layer (not shown) on the surface of the peel-preventing layer 3 by sputtering or plating, or by laminating a conductive metal foil, nonwoven fabric, or the like on the peel-preventing layer 3.

[0072] <Electronic Device> The electronic component mounting substrate according to the present disclosure is preferably provided in electronic devices such as liquid crystal displays, touch panels, notebook PCs, mobile phones, smartphones, and tablet terminals.

[0073] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the following examples. Note that the "parts" below are values ​​based on "parts by mass" unless otherwise specified.

[0074] <<Raw Materials>> The raw materials used in the examples are as follows. <Thermosetting Resins> Thermosetting resin (r1): polyurethane resin (molecular weight (Mw) = 130,000, acid value 10 mg KOH / g, Tg = 20°C), manufactured by Toyochem Co., Ltd. Thermosetting resin (r2): polyurethane resin (molecular weight (Mw) = 125,000, acid value 10 mg KOH / g, Tg = -6°C), manufactured by Toyochem Co., Ltd. Thermosetting resin (r3): acrylic resin (molecular weight (Mw) = 55,000, acid value 7 mg KOH / g, Tg = -20°C), manufactured by Toyochem Co., Ltd.

[0075] <Curable Compounds> Curable compound (c1): tetrafunctional epoxy resin "TETRAD-X" (epoxy equivalent = 100 / eq), manufactured by Mitsubishi Chemical Corporation. Curable compound (c2): bifunctional epoxy resin "jER828" (epoxy equivalent = 189 g / eq), manufactured by Mitsubishi Chemical Corporation. Curable compound (c3): bifunctional epoxy resin "AER9000" (epoxy equivalent = 380 g / eq), manufactured by Asahi Kasei E-materials Corporation.

[0076] <Lubricant> Lubricant (L1): Carnauba wax "CERACOL 79" (non-volatile content 20% by mass), manufactured by BYK

[0077] <Filler (B)> Filler f1: carbon black “MA100” (trade name, average primary particle diameter: 24 nm, BET specific surface area: 120 m ２ / g) Mitsubishi Chemical Corporation Filler f2: Silica "Ultrasil U360" (trade name, average primary particle diameter: 28 nm, BET specific surface area: 50 m ２ / g) Filler f3: Silica "Admafine SO-C5" (trade name, average primary particle diameter: 2.0 μm, BET specific surface area: 2.1 m) manufactured by NANOCYL Corporation ２ / g), Admatechs Co., Ltd. Filler f4: plate-shaped boron nitride "HP-1" (trade name, average primary particle diameter: 9.0 μm, BET specific surface area: 3.1 m) ２ / g), JFE Mineral Co., Ltd. Filler f5: Silica "EXELIKA SE-30K" (trade name, average primary particle diameter: 25.1 μm, BET specific surface area: 0.7 m) ２ / g) manufactured by Tokuyama Corporation. Filler f6: flake silver powder "FA-S-18" (trade name, average primary particle diameter: 3.1 μm, BET specific surface area: 2.0 m) ２ / g), Filler f7: Dendritic silver-coated copper powder "ACAX-225M" (trade name, average primary particle diameter: 7.4 μm, BET specific surface area: 0.86 m), manufactured by DOWA Corporation. ２ / g), manufactured by Mitsui Mining & Smelting Co., Ltd.

[0078] <<Measurement Method>> <Change Rate X of Static Friction Coefficient During Reciprocating Abrasion Test> For the anti-exfoliation layers of each Example and Comparative Example, a smooth area of ​​6 mm x 6 mm or more on a chip (electronic component) or electronic component mounting substrate made of molded resin (sealing resin) in the resin-containing region below the anti-exfoliation layer was used as the test sample to measure the static friction coefficient μk using a continuous load surface property measuring instrument HEIDON Tribogear Type: 22H (manufactured by Shinto Scientific Co., Ltd.), with the fully dried test sample attached to the test table and a load of 100 g applied to the friction probe, at the 100th and 300th reciprocating cycles. １００ , μ ３００ The static friction coefficient μk was recorded. A ball indenter was used as the measuring tool when moving back and forth on the surface of the test sample, and a SUS ball (φ (diameter) 3.0 mm) was used as the friction probe. １００ , μ ３００ was applied to the following [Equation 1] to calculate the change in static friction coefficient X during the reciprocating wear test. [Equation 1] X = (μk ３００ -μk １００ ) / μ k １００ ×100

[0079] <Index Y> As shown in FIG. 2, the peel-preventing layer 3 and the electronic component mounting substrate 12 of each example and comparative example, which were produced by the method described below, were cross-sectioned by a polishing method, and the radius of curvature R of the curved surface of the corners of the electronic component and the peel-preventing layer covering it was measured using a digital microscope VHX-7000 (product name, manufactured by Keyence Corporation). １ , R ２ Similarly, the thickness of the thinnest part of the corner of the peeling-preventing layer (corner thickness of the peeling-preventing layer) A １ The MLCC used in the evaluation of these electronic components and anti-exfoliation layers was one with a short side of 0.3 mm and a long side of 0.6 mm (hereinafter also referred to as 0603MLCC, 0603MLCC30). １ , R ２ , Corner thickness A of the anti-peeling layer １ was applied to the following [Equation 2] to calculate the index Y. [Equation 2] Y = R ２ / (R １ +A １ )

[0080] <Thickness A of peeling prevention layer ２The thickness of the peeling prevention layer on the electronic component mounting substrate was measured at the thickest point on the upper surface of the electronic component, which was observed by a digital microscope VHX-7000 (product name, manufactured by Keyence Corporation) after cutting the cross section by a polishing method. Five samples of cross sections of different electronic component mounting substrates were similarly measured, and the average value was taken as the thickness A. ２ It was decided.

[0081] <Average particle size of filler (B)> The average particle size of filler (B) was determined from the average value of 20 primary particles observed in an image magnified approximately 50,000 to 1,000,000 times by a transmission electron microscope (TEM). When the particle shape of filler (B) has an average aspect ratio (major axis length / minor axis length) of 1.5 or more, the average particle size was determined by averaging the major axis lengths.

[0082] <Maximum Point Stress T of Anti-Peeling Layer> The anti-peeling sheet with release film of each Example and Comparative Example was heated at 180°C for 2 hours and cut into a size of 20 mm wide x 60 mm long. The release film was then peeled off to obtain a measurement sample (anti-peeling layer) made of the anti-peeling sheet. Each measurement sample (anti-peeling layer) was placed in an atmosphere (air, 50% RH (relative humidity)) ranging from room temperature (e.g., 25°C) to 100°C. One minute later, a tensile test was performed at the same temperature, under conditions of a tensile speed of 50 mm / min and a relative humidity of 50% using a small tabletop testing machine EZ-TEST (trade name, manufactured by Shimadzu Corporation) with an effective tensile size of 20 x 23 mm. The maximum stress T (maximum point stress T) at a tensile speed of 50 mm / min was then determined.

[0083] <Glass Transition Temperature Tg> The Tg of the measurement sample (anti-exfoliation layer) of each Example and Comparative Example was measured using a dynamic viscoelasticity measuring device DVA-200 (trade name, manufactured by IT Measurement & Control Co., Ltd.) in accordance with JIS K7198. The measurement sample was prepared by cutting the anti-exfoliation layer of each Example to a size of 0.5 cm x 3 cm and removing the release film. The Tg was determined as the temperature at which the main dispersion peak of the loss tangent (tan δ) appeared, measured under tensile deformation conditions of 0.08%, a frequency of 10 Hz, and a heating rate of 10°C / min. However, if the anti-exfoliation layer was brittle and broke during the measurement, the Tg could not be calculated from the measurement results, and this was indicated as "measurable" in the Example Tables.

[0084] Preparation of Anti-Peeling Sheet Example 1 100 parts of thermosetting resin r1 (solid content), 2.0 parts of curing agent c1, 10 parts of curing agent c2, 2.9 parts of filler f1, and 159 parts of filler f4 were charged into a container, and a mixed solvent of toluene: isopropyl alcohol (mass ratio 2:1) was added to a non-volatile content of 45% by mass, and the mixture was stirred with a disperser for 10 minutes to obtain a composition. This composition was applied to a release sheet using a doctor blade to a dry thickness of 80 μm. The anti-peeling sheet of Example 1 was then obtained by drying at 100 ° C. for 2 minutes.

[0085] [Examples 2 to 21, Comparative Examples 1 to 4] Exfoliation-preventing sheets (laminate sheets) according to Examples 2 to 21 and Comparative Examples 1 to 4 were obtained in the same manner as above, except that the types and blending amounts of the materials in Tables 1 to 3 were changed. The evaluation results of each exfoliation-preventing sheet, which will be described later, are also shown.

[0086] [Preparation of Electronic Component Mounting Substrate 1] (Preparation of Mounting Substrate) A substrate (mounting substrate) was prepared by mounting 5 × 1 mold-sealed electronic components (1 cm × 1 cm) and 8 × 2 arrays of 0603MLCCs (length 0.6 mm, width 0.3 mm) on a glass epoxy substrate. The substrate thickness was 0.6 mm, and the mold sealing thickness, i.e., the height (component height) H from the top surface of the substrate to the top surface of the mold sealing material, was 0.7 mm. The mounting interval of the 0603MLCCs was 200 μm.

[0087] The peel-preventing sheets of each Example and Comparative Example were thermocompression-bonded to the mounting substrate at 2 MPa and 180°C for 5 minutes, and the cushioning material was peeled off by hand. After that, heating was carried out at 180°C for 2 hours, and an electronic component mounting substrate of each Example and Comparative Example was obtained based on Tables 1 to 3.

[0088] <Evaluation> [Abrasion Resistance] For the anti-peeling layers of each Example and Comparative Example, the anti-peeling layer on the mold-sealed electronic components of the mounting substrate was used as the test area. Using a continuous load surface property measuring instrument, HEIDON Tribogear Type: 22H (trade name, manufactured by Shinto Scientific Co., Ltd.), a fully dried test sample was attached to a test stand, a 100 g load was applied to the friction probe, and the surface condition of the test sample was observed after the number of reciprocating movements specified below. Then, it was confirmed whether the substrate was exposed or the anti-peeling layer was torn (reciprocating abrasion test). When these evaluations were difficult to make visually, the surface condition was observed at 20x magnification using a digital microscope VHX-7000 (trade name, manufactured by Keyence Corporation). A ball indenter was used as the measurement tool when reciprocating the test sample surface, and a SUS ball (φ3.0 mm) was used as the friction probe. Furthermore, from these results, the abrasion resistance was evaluated according to the following criteria. (Evaluation criteria) +++: After 500 reciprocating motions, the electronic components beneath the anti-peeling layer were not exposed. (Very good) ++: After 400 reciprocating motions, the electronic components beneath the anti-peeling layer were not exposed, but after 500 reciprocating motions, the electronic components beneath the anti-peeling layer were exposed. (Good) +: After 300 reciprocating motions, the electronic components beneath the anti-peeling layer were not exposed, but after 400 reciprocating motions, the electronic components beneath the anti-peeling layer were exposed. (Practical level) NG: After fewer than 300 reciprocating motions (i.e., after 300 reciprocating motions), the electronic components beneath the anti-peeling layer were exposed. (Poor)

[0089] [Peeling Resistance] As shown in Figure 5, the edge of a thick Ni-SUS plate 13 (a commercially available SUS304 plate with a thickness of 0.2 mm and a nickel layer of 2 μm formed on the surface) was placed at a 45° angle against the peeling-preventive layer 3 on the corner of each 0603MLCC 30 of the electronic components 2 on the electronic component mounting substrate fabricated by the above-mentioned method, and each 0603MLCC 30 was flicked from the side of the corner toward the top. This was repeated 30 times for each location, and after applying this to the peeling-preventive layer 3 on all 16 0603MLCC 30 mounted on the electronic component mounting substrate 12, the number of electronic components 30 that peeled off from the electronic component mounting substrate was counted and evaluated as peeling resistance (peeling test). Here, when a similar test was performed on 0603MLCC without a peeling-preventive layer, the components peeled off after about 10 tests. Peeling refers to a state in which, compared to before the test, breakage has occurred between the electronic component mounting board and the electronic component, or between the electronic component mounting board and the peeling prevention layer, causing peeling or separation, resulting in a loss of contact between the electronic component mounting board and the electronic component in some places. (Evaluation criteria) +++: The number of peeled MLCCs is 0. (Very good) ++: The number of peeled MLCCs is 1. (Good) +: The number of peeled MLCCs is 2 or 3. (Practical level) NG: The number of peeled MLCCs is 4 or more. (Poor)

[0090] [Scratch Resistance] A 30 mm x 80 mm Ni-SUS plate (a commercially available SUS304 plate with a thickness of 0.2 mm and a nickel layer of 2 μm formed on the surface) was prepared. The anti-exfoliation sheets (25 mm x 70 mm) of each Example and Comparative Example were thermocompression-bonded to the plate at 2 MPa and 180°C for 5 minutes, and the cushioning material was peeled off by hand. The plate was then heated at 180°C for 2 hours to obtain a measurement sample (anti-exfoliation layer). A scratch test was performed on the measurement sample in accordance with JIS K7317 using a continuous load surface property tester, HEIDON Tribogear Type: 22H (trade name, manufactured by Shinto Scientific Co., Ltd.), to continuously measure the vertical load at which the anti-exfoliation sheet coated on the substrate peeled off at 50 mm / min. A diamond needle (0.25 mmR) was used to scratch the surface of the test sample, and scratch resistance was evaluated according to the following criteria depending on the load when the substrate was exposed from the measurement sample. Note that the scratch in scratch resistance refers to a state in which the anti-exfoliation layer is cracked or stretched when the tip of the scratching tool scratches the anti-exfoliation layer, causing the layer to peel off and expose the substrate, and does not refer to needle marks that are likely to cause observation results to vary depending on the observer. (Evaluation Criteria) +++: Vertical load when substrate is exposed ≥ 350 g (very good) ++: Vertical load when substrate is exposed ≥ 250 g (good) +: Vertical load when substrate is exposed ≥ 200 g (usable) NG: Vertical load when substrate is exposed ≥ 200 g (poor)

[0091] [Reliability] A molded resin substrate (60 mm x 50 mm) was prepared, and a peel-preventing sheet (55 mm x 45 mm) from each Example and Comparative Example was thermocompression-bonded to the substrate at 2 MPa and 180°C for 5 minutes. The cushioning material was then manually peeled off. The substrate was then heated at 180°C for 2 hours to obtain a measurement sample (peeling-preventing layer). Using a cross-cut guide in accordance with JIS K5600, 25 1-mm-spaced grids were created on the peel-preventing layer surface of the electronic component. Then, adhesive tape was applied to the measurement sample, and the edge of the tape was quickly peeled off at a 45° angle to perform a cross-cut test. Nichiban adhesive tape with a width of 18 mm was used. The state of the peel-preventing layer remaining on the molded resin substrate (cross-cut survival rate) was evaluated according to the following criteria. (Evaluation Criteria) +++: Indicates a cross-cut survival rate of 100 / 100. (Very good) ++: A cross-cut residual rate of 95 to 99 / 100 was exhibited. (Good) +: A cross-cut residual rate of 80 to 94 / 100 was exhibited. (Practical) NG: A cross-cut residual rate of less than 80 / 100 was exhibited. (Poor) An encapsulating sheet was produced in the same manner as in Example 1, except that the content, thickness Ta, and protective film were changed to those shown in Tables 1 to 3, and evaluated in the same manner. Note that any cross-linking agent, oligomer, monomer, polymerization initiator, and other components were also added at the same time.

[0092]

[0093]

[0094]

[0095] It was confirmed that an anti-exfoliation layer in which the rate of change X of the static friction coefficient is less than −50% or exceeds 200% has problems with abrasion resistance and anti-exfoliation properties, as shown in Comparative Example 1 or 2. It was confirmed that an anti-exfoliation layer in which the index Y is less than 0.8 or exceeds 20.0 has problems with anti-exfoliation properties, as shown in Comparative Example 3 or 4. In contrast, it was confirmed that the anti-exfoliation layer of this example, which satisfies both (1) and (2) of claim 1 described above, is excellent in abrasion resistance, anti-exfoliation properties, scratch resistance, and reliability.

[0096] This application claims priority based on Japanese Patent Application No. 2023-202349, filed November 30, 2023, the disclosure of which is incorporated herein in its entirety by reference.

[0097] 1: Substrate 2: Electronic component 3: Anti-peeling layer 4: Solder bump 5: Hollow portion 6: Anti-peeling sheet 7: Cushioning material 8: Functional layer 9: Ground 10: Electronic component mounting substrate 11: Electronic component mounting substrate 12: Electronic component mounting substrate with functional layer 13: Ni-SUS plate 20: Heating and pressing machine 30: 0603MLCC 100: Mounting substrate

Claims

1. An electronic component mounting substrate comprising: a substrate; electronic components mounted on at least one surface of the substrate; and a peeling-preventive layer covering the substrate and the electronic components, the peeling-preventive layer satisfying both of the following (1) and (2): (1) The rate of change X of the static friction coefficient calculated by the following [Formula 1] is -50% or more and 200% or less. X = (μk ３００ -μk １００ ) / μ k １００ ×100 [Formula 1] (μk １００ The static friction coefficient of the anti-exfoliation layer after 100 reciprocating abrasion tests, μk ３００ (2) The index Y calculated by the following [Equation 2] is 0.8 or more and 20.0 or less. Y=R ２ / (R １ +A １ ) [Formula 2] (R １ the radius of curvature of the curved surface of the corner of the electronic component in the cross section of the electronic component mounting substrate, R ２ the radius of curvature of the corner of the peel-off prevention layer in the cross section of the electronic component mounting substrate, A １ (thickness of the corner of the peel-off prevention layer in the cross section of the electronic component mounting substrate) 2. The anti-exfoliation layer contains a binder (A) and a filler (B), and the BET specific surface area [m ２ / g] and the content [mass %] of the filler (B) in 100 mass % of the peeling prevention layer is 0.01 to 15 [mass % m ２ 2. The electronic part mounting board according to claim 1, wherein the surface area of ​​the electronic part mounting board is 100 nm.

3. Thickness A of the peeling prevention layer ２ The electronic part mounting board according to claim 1 or 2, wherein the thickness is 5 to 300 μm.

4. An electronic device equipped with an electronic component mounting board according to any one of claims 1 to 3.

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