Electronic component mounting boards and electronic devices

Abstract

To provide an electronic component mounting substrate which is excellent in adhesion and scratch resistance, and which is, after machining, provided with a fall prevention layer increasing the smoothness of component corner portions so as to firmly cover the substrate and an electronic component on the substrate thereby preventing 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 preventing the electronic component from falling from the substrate because of external damage.SOLUTION: The electronic component mounting substrate comprises a substrate, an electronic component, and a fall prevention layer. The fall prevention layer satisfies the following conditions: (1) a static friction coefficient change rate X obtained by the formula 1, X=(μk300-μk100) / μk100×100), is from -50% to 200% inclusive; and (2) an exponent Y obtained by the formula 2, Y=R2 / (R1+A1), is from 0.8 to 20.0 inclusive.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention Peeling prevention sheet and Anti-peeling layer Regarding. [Background technology]

[0002] Because terminal electronic devices such as smartphones and wearable devices are used in a wide variety of environments, high reliability is required to prevent malfunctions even under harsh conditions. Furthermore, as electronic devices have become smaller and lower profile, the size of the circuit boards on which the electronic components are mounted has also decreased, and the contact area between the circuit board and the electronic components has decreased. As a result, the adhesion between the electronic components and the circuit board has decreased, which can cause electronic components to detach from the circuit board. Therefore, there is a growing need to prevent damage and slippage of electronic components due to physical damage, heat, and humidity. Therefore, a method is known to protect electronic components such as IC chips and MLCCs (multilayer ceramic capacitors) from external damage by embedding them in a resin layer (Patent Document 1). However, from the perspective of reducing the height of electronic component mounting substrates and cutting costs, there is a need to form a protective layer that is thinner and has a reduced thickness after processing. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-004314 [Overview of the project] [Problems that the invention aims to solve]

[0004] As mentioned above, inventions relating to coated and protected electronic component mounting substrates have been disclosed. However, thinning the protective layer leads to many problems, as described below, and there is a need 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 circuit board using solder or adhesive. After the circuit board is assembled into an electronic device and undergoes reliability testing, the components may detach or become misaligned from the board due to human fingernails or other components catching on them during these processes. In recent years, the miniaturization and reduction of electronic components, such as multilayer ceramic capacitors (MLCCs), have progressed rapidly, and as a result, the contact area with the circuit board has decreased, reducing the adhesion between the components and the board, thus increasing the importance of preventing the detachment of the aforementioned electronic components.

[0006] Furthermore, protective materials with sufficient abrasion and scratch resistance are required to withstand contact and friction between hard materials such as metal and electronic components. In addition, there is 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 and high-humidity environments.

[0007] The objective of the present invention is to provide a highly reliable electronic component mounting substrate that is miniaturized and low-profile, exhibits excellent abrasion resistance and scratch resistance, prevents electronic components from falling off due to external damage, and can be used for a long period of time under high temperature and high humidity conditions. [Means for solving the problem]

[0008] As a result of diligent research, the inventors have found that the above-mentioned problems can be solved by using articles (electronic component mounting substrate, peeling prevention layer, and peeling prevention sheet) having the following characteristics, and have completed the present invention. That is, the present invention relates to an electronic component mounting substrate, a peeling prevention layer, and a peeling prevention sheet characterized as shown below. [1]: A substrate, an electronic component mounted on at least one side of the substrate, and the substrate and An electronic component mounting substrate comprising a peeling prevention layer covering the aforementioned electronic component, wherein the peeling prevention layer satisfies all of (1) and (2). (1) The rate of change X of the static friction coefficient, calculated using the following [Equation 1], is between -50% and 200%. X = (μk300 - μk100) / μk100 × 100 [Equation 1] (μk100: Coefficient of static friction at the 100th reciprocating wear test of the peeling prevention layer, μk300: Coefficient of static friction at the 300th reciprocating wear test of the peeling prevention layer) (2) The exponent Y obtained by the following [Equation 2] is 0.8 or more and 20.0 or less. Y = R2 / (R1 + A1) [Equation 2] (R1: Radius of curvature of the curved surface of the corner of the electronic component in the cross-section of the electronic component mounting substrate, R2: Radius of curvature of the corner of the peeling prevention layer in the cross-section of the electronic component mounting substrate, A1: Thickness of the corner of the peeling prevention layer in the cross-section of the electronic component mounting substrate) [2]: The peeling prevention layer includes a binder (A) and a filler (B). The product of the BET specific surface area [m2 / g] of the filler (B) and the content [% by mass] of the filler (B) in 100% by mass of the peeling prevention layer is 0.01 to 15 [% by mass·m2 / g]. The electronic component mounting substrate according to [2]. [3]: The thickness A2 of the peeling prevention layer is 5 to 300 μm. The electronic component mounting substrate according to [1]. [4]: An electronic device on which the electronic component mounting substrate according to any one of [1] to [3] is mounted.

Advantages of the Invention

[0009] According to the present disclosure, it is possible to provide an electronic component mounting substrate in which peeling of electronic components due to external damage is suppressed over a long period even in a miniaturized and low-profile electronic component mounting substrate, and an electronic device on which this is mounted.

Brief Description of the Drawings

[0010] [Figure 1] It is a schematic cross-sectional view of an electronic component mounting substrate according to the present embodiment. [Figure 2] It is a schematic cross-sectional view of an electronic component mounting substrate according to the present embodiment, showing R1, R2, and A1 on the curved surface of the corner of the electronic component that constitute the exponent Y. [Figure 3] It is a diagram showing a part of the flow of the manufacturing process of the electronic component mounting substrate according to the present embodiment. [Figure 4] This is a schematic cross-sectional view showing an example of an electronic component mounting substrate according to this embodiment. [Figure 5] This is a diagram showing an evaluation method of an electronic component mounting substrate according to an example.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution means of the invention. 《Electronic Component Mounting Substrate》

[0012] As shown in FIG. 1, the electronic component mounting substrate of the present invention includes a substrate 1, an electronic component 2 mounted on the substrate 1, and a peeling prevention layer 3 that covers and protects the substrate 1 and the electronic component. The substrate 1 or the electronic component 2 has a region containing a resin component (not shown), and the peeling prevention layer 3 covers its surface.

[0013] The substrate 1 may be any substrate that can mount the electronic component 2 and can withstand the molding process for each application, and can be arbitrarily selected. Electrodes, wiring patterns, vias (not shown), etc. can be arbitrarily provided on the substrate 1. The substrate may have rigidity or flexibility. For example, a work board, a mounting module substrate, a printed wiring board, or a build-up board formed by a build-up method or the like in which a conductive pattern made of copper foil or the like is formed on the surface and / or inside. Examples include build-up substrates.

[0014] Examples of the electronic component 2 include components molded from wafers and wires such as connectors, film capacitors, and IC chips, inductors, thermistors, MLCCs, coils, diodes, electrolytic capacitors, crystal oscillators, etc. Among these, MLCCs and IC chips are preferred as objects to be applied to the present invention because of their progress in miniaturization.

[0015] When multiple electronic components 2 are mounted, their shapes and heights may be the same or different.

[0016] The size and height of electronic component 2 are not particularly limited, but given the recent trend towards miniaturization and low profile, a height of 3 mm or less is preferred. The shape of the IC chip can be rectangular, cylindrical, coin-shaped, thin-film, etc. MLCCs are preferably in the mainstream package sizes of 0402 (length 0.4 mm, width 0.2 mm) and 0603 (length 0.6 mm, width 0.3 mm), but larger ones such as 1005 and 1608 may also be used. Inductor shapes include sonorade, dome-type coil, and flat-plate coil. Thermistors include surface-mount rectangular, cylindrical, and leaded types.

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

[0018] The peeling prevention layer 3 may cover and protect the electronic component 2 and the substrate 1 while maintaining the hollow portion 5, or it may cover and protect the electronic component 2 and the substrate 1 while filling the hollow portion 5. The peeling prevention layer can be manufactured by the method described later.

[0019] The peeling prevention layer 3 covers the substrate and the electronic component. In Figure 1, it covers the top surface and side surface of the electronic component 2, and further extends to the entire surface or part of the edge surface of the substrate 1. In other words, the covering layer 3 is provided so as to follow the stepped portion (uneven portion) formed by the mounting of the electronic component 2. The peeling prevention layer 3 is formed using a peeling prevention sheet, which is a precursor of the peeling prevention layer 3. The method for forming the peeling prevention layer 3 from this peeling prevention sheet is not limited, but one of the following methods is preferred: press molding, the three-dimensional surface coating method TOM (Three-dimensional Overlay Method) molding, vacuum molding, pressure molding, vacuum pressure molding, or injection molding. Among these, the press molding method is particularly preferred for this peeling prevention sheet.

[0020] In the example shown in Figure 1, an example is described in which the electronic component 2 is mounted on one surface of the substrate 1. However, the electronic component 2 may be mounted on both sides of the substrate, and both sides of the substrate may be covered with a peel-preventing layer.

[0021] 《Peeling prevention layer》 Next, the delamination prevention layer of the present invention will be described in more detail. As described above, the delamination prevention layer is intended to prevent the group of electronic components arranged on the substrate from delaminating from the substrate.

[0022] The peeling prevention layer must satisfy all of the following conditions (1) and (2). (1) The rate of change X of the static friction coefficient, calculated using the following formula 1, is between -50% and 200%. (2) The exponent Y calculated by the following formula 2 is between 0.8 and 20.0. Note that these numerical values ​​X and Y are calculated using the following formulas [Equation 1] and [Equation 2], and X The measurement of Y follows the methods and conditions described in the respective examples.

[0023] 《Rate of change of static friction coefficient X》 The rate of change X of the static friction coefficient obtained by the reciprocating wear test of the peeling prevention 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 -μk100 ) / μk 100 × 100 [Equation 1]

[0024] Here, μk 100 is the coefficient of static friction at the 100th reciprocating wear test of the anti-peeling layer, and μk 300 is the coefficient of static friction at the 300th reciprocating wear test of the anti-peeling layer. The above coefficient of static friction μk 100 , μk 300 The measurement method will be described in detail in the examples.

[0025] The change rate X of the coefficient of static friction is tested using a wear testing machine and compared with the number of times when the coefficient of static friction during measurement is stable and the number of times serving as a criterion for determining the presence or absence of wear resistance. Therefore, the coefficient of static friction μk 100 at the 100th time and the coefficient of static friction μk 300 at the 300th time, which is an index for the presence or absence of wear resistance, are used for calculation. The change rate X of the coefficient of static friction indicates a state of maintaining a constant coefficient of static friction when the reciprocating wear test is continued, that is, it is an index for confirming wear resistance. Also, when the change rate X of the coefficient of static friction is positive, it represents the progress of wear, and the larger the value, the lower the wear resistance. When it is negative, it indicates that the progress of wear is small and the sliding on the surface of the anti-peeling layer has increased. This is considered to be affected by the filler exposed when the film surface is worn, the wear powder on the surface of the anti-peeling layer, and frictional heat.

[0026] In addition, the test using the above wear testing machine is performed on the smooth surface of the anti-peeling layer formed on the resin-containing region of the electronic component or the base material from the viewpoint of obtaining stable measurement values. The resin region refers to a part whose surface such as a mold resin or a glass epoxy resin is covered with resin.

[0027] In the present invention, the change rate X of the coefficient of static friction is -50% or more and 200% or less, whereby the wear resistance of the anti-peeling layer on the electronic component mounting substrate can be improved. X is preferably -25% or more and 150% or less, and more preferably -5% or more and 100% or less. By setting the change rate X within the above range on the anti-peeling layer, the anti-peeling layer is less likely to be damaged, and the wear 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 peeling prevention layer, including conventionally known methods. For example, methods include improving resistance to friction by hardening the surface of the peeling prevention layer by adjusting the compounding components, improving the slipperiness of the lubrication surface by adding wax components to the peeling prevention layer, reducing surface irregularities by reducing the amount or changing the shape of the added particulate components (reducing the surface friction coefficient), increasing the heat resistance of the peeling prevention layer, and reducing surface irregularities by changing the type of protective film used when forming the peeling prevention sheet, which is a precursor to the peeling prevention layer, on the electronic component mounting substrate. While the methods for controlling the wear resistance of the peeling prevention layer surface are not limited to those exemplified, methods that harden the surface by increasing the amount of hardener in the peeling prevention layer, or methods that reduce surface irregularities by adjusting the amount and shape of particulate matter in the peeling prevention layer, are preferable from a productivity standpoint, as they eliminate the need for pre / post-treatment.

[0029] 《Index Y》 The delamination prevention layer in this invention is determined by the following [Equation 2], where the index Y is between 0.8 and 20.0. By setting the value within this range, an appropriate shape is obtained that smoothly covers the surface of the electronic component mounting substrate and prevents the electronic components from delaminating. From the viewpoint of uniformity of the peeling prevention layer thickness (adhesion to components) and ensuring thickness at the corners of electronic components, a value of 0.9 to 12.0 is preferred, and 1.0 to 5.0 is more preferred. Y=R2 / (R1+A1) [Formula 2] In [Equation 2], R2, R1, and A1 are determined from the measured values ​​of the cross-section when the electronic component mounting substrate shown in Figure 2 is cross-sectioned perpendicular to the substrate surface. R1 is the radius of curvature of the curved surface at the corner of the electronic component in the cross-section of the electronic component mounting substrate, R2 is the radius of curvature of the corner of the peeling prevention layer mounted on the electronic component mounting substrate in the cross-section, and A1 is the corner thickness of the peeling prevention layer in the cross-section of the electronic component mounting substrate (hereinafter, peeling prevention layer corner thickness A1). The cross-section of an electronic component-mounted substrate can be prepared using dicing or polishing methods, and the R2, R1, and A1 dimensions can be determined from this cross-section by measuring its length using, for example, a digital microscope VHX-7000 (manufactured by Keyence Corporation). Note that the radii of curvature R1 and R2 indicate the points at each corner where snagging is most likely to occur, and therefore refer to the radii of curvature that yield the minimum value when measured at each corner.

[0030] The index Y is a value that represents the change in smoothness between the corner of an electronic component and the corner of the anti-peeling layer on the electronic component. By setting the index Y within the above range, it is possible to prevent the electronic component from peeling off due to snagging between the electronic component and fingernails or other components, which can occur during inspection of the electronic component mounting substrate or when mounting the electronic component mounting substrate into an electronic device in a later process.

[0031] The index Y can be controlled by adjusting the conformability and fluidity of the delamination prevention sheet to the electronic components during processing. Specifically, this can be done by selecting the binder (A) and filler (B) that make up the delamination prevention sheet as described later, by adjusting the conformability of the delamination prevention sheet to the substrate and electronic components by adjusting the processing conditions (processing temperature, processing time, pressure conditions, vacuum level, etc.) during the processing of the delamination prevention sheet, and by controlling the fluidity of the delamination prevention sheet by changing the lamination configuration during processing. Different methods can be applied, or common methods can be applied.

[0032] 《Binder (A)》 Anti-peeling layer and peeling prevention sheet This includes a binder (A). Binder (A) is a peeling prevention layer. and peeling prevention sheet It serves as a base and has the function of supporting filler (B) and other optional components, as described later. 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. While not particularly limited, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, and fluororesins are more preferred from the viewpoint of heat resistance. Thermoplastic resins can be used alone or in combination of two or more types.

[0034] [Thermosetting resin] Thermosetting resins are resins that have multiple functional groups that can react with curable compounds. 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 acrylic resins, maleic acid resins, polybutadiene resins, polyester resins, polyurethane resins, polyurethane urea resins, epoxy resins, oxetane resins, phenoxy resins, polyimide resins, and poly Known resins include amide resins, polyamide-imide resins, phenolic resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, and fluororesins. Thermosetting resins can be used alone or in combination of two or more types.

[0035] Among these, polyurethane resin, polyurethane urea resin, polyester resin, epoxy resin, phenoxy resin, polyimide resin, polyamide resin, and polyamide-imide resin are preferred in terms of heat resistance.

[0036] [Curable compound] Curable compounds have multiple functional groups that can react with the functional groups of thermosetting resins. Examples of known curable compounds include epoxy compounds, acid anhydride group-containing compounds, isocyanate compounds, aziridine compounds, amine compounds, phenol compounds, and organometallic compounds. The curable compounds can be used alone or in combination of two or more types.

[0037] The curable compound is preferably bifunctional or more, and more preferably contains a curable compound with three or more functions. From the viewpoint of adjusting the crosslinking density and achieving both the suitability for processing during the molding of electronic component mounting substrates as described later, and the temporal stability of the composition which is a precursor of the peeling prevention sheet, it is desirable to use a combination of a bifunctional curable compound and a curable compound with three or more functions. The composition can also be adjusted by controlling the content of the curable compound. By adjusting the content of the curable compound as described below, a strong cross-linked structure is formed in the peeling prevention layer, improving the adhesion between the peeling prevention layer and the substrate and enhancing reliability.

[0038] The bifunctional curable compound is preferably present in 1 to 50 parts by mass of each type, and more preferably in 15 to 30 parts by mass, per 100 parts by mass of thermosetting resin. By increasing the amount of the bifunctional curable compound to 1 part by mass or more, a strong cross-linked structure is formed in the peeling prevention layer, improving resistance to thermal damage. Furthermore, by increasing it to 15 parts by mass or more, the hardness and strength of the surface of the peeling prevention layer can be adjusted, improving wear resistance. On the other hand, by keeping the amount of the curable compound at 50 parts by mass or less, excessive hardening of the peeling prevention layer is suppressed, and cracking due to shrinkage after the peeling prevention sheet hardens is suppressed.

[0039] The curable compound with three or more functions preferably contains 0.2 to 20 parts by mass of each type, 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 thermosetting resin. A concentration of 0.8 parts by mass or more improves the adhesion between the delamination prevention layer and the substrate, thereby enhancing reliability. Furthermore, a concentration of 5 parts by mass or less of the curable compound with three or more functions allows the delamination prevention sheet 6 to deform to conform to the shape of the electronic components during heating and pressurizing in the manufacturing process of the electronic component-mounted substrate described later, thereby forming a defect-free delamination prevention layer.

[0040] [Lubricant] Anti-peeling layer and peeling prevention sheet The material may contain lubricants such as wax. Adding these increases the slipperiness of the surface of the anti-spray layer, improving wear resistance. Improved reliability can also be expected by making the surface of the anti-spray layer less prone to cracking. Examples of waxes include: animal and plant-based waxes such as beeswax, lanolin wax, whale wax, candelilla wax, carnauba wax, rice wax, wood wax, jojoba oil, and palm oil; mineral and petroleum-based waxes such as montane wax, ozogerite, ceresin, paraffin wax, microcrystalline wax, and petrolatum; and synthetic waxes such as Fischer-Tropsch wax, polyethylene wax, oxidized polyethylene wax, oxidized polypropylene wax, montane wax derivatives, paraffin wax derivatives, microcrystalline wax derivatives, and Teflon® wax. etc. These are some examples.

[0041] Filler (B) Anti-peeling layer and peeling prevention sheet This material contains filler (B). By appropriately changing the type, average particle size, and amount of filler (B), the rate of change X of the exponent Y and static friction coefficient can be controlled. Furthermore, by adjusting the cohesive force in the peeling prevention layer, mechanical properties such as the maximum point stress T can be kept within a favorable range. Insulating fillers are used when insulation is required, conductive fillers when conductivity is required, and electromagnetic wave absorbing fillers when electromagnetic wave absorption is required. The shape of the filler 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. Preferred examples include combinations of spherical fillers with an average particle diameter that differs by 10 times or more, and combinations of flake-shaped and dendritic fillers.

[0042] Examples of insulating fillers include non-metallic inorganic fillers such as silica, alumina, boron nitride, aluminum nitride, magnesium silicon nitride, silicon carbide, titania, glass, and ceramics. Insulating fillers can be used individually or in combination of two or more types.

[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 type 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 electromagnetic wave absorbing fillers include iron alloys such as iron, Fe-Ni alloy, Fe-Co alloy, Fe-Cr alloy, Fe-Si alloy, Fe-Al alloy, Fe-Cr-Si alloy, Fe-Cr-Al alloy, and Fe-Si-Al alloy; ferrite materials 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 carbon fillers include acetylene black, Ketjen black, furnace black, carbon black, carbon fiber, carbon nano-nanotube fillers, graphene fillers, graphite fillers, and carbon nanowalls.

[0045] The average particle size of filler (B) is preferably 0.005 to 50 μm. From the viewpoint of maintaining the smoothness of the surface of the peeling prevention layer, reducing the effect of wear particles when worn, and improving wear resistance, 0.02 to 20 μm is more preferable.

[0046] Anti-peeling layer or peeling prevention sheet The content of filler (B) in 100% by mass is preferably 0.1 to 80% by mass, and more preferably 1.0 to 35% by mass from the viewpoint of improving surface properties and scratch resistance while suppressing the shedding of filler (B) from the surface of the peeling prevention layer. When the content of filler (B) is 35% by mass or less, the abrasion resistance improves.

[0047] centre BET specific surface area of ​​Filler (B) [m²] 2 / g] and 、 Anti-peeling layer or peeling prevention sheet The product of the specific surface area and the content [mass%] in 100% by mass (hereinafter referred to as the product of specific surface area and content) is preferably 0.01 to 15, and 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 peeling prevention layer. or peeling prevention sheet This is the sum of the products of the specific surface area and content of each filler (B) contained in the mixture. When the product of the specific surface area and the content is within the above range, the filler (B) acts as a reinforcing material in the peeling prevention sheet, thereby preventing the peeling prevention sheet 6 from breaking during heating and pressurizing in the manufacturing process of the electronic component mounted substrate described later, and forming a defect-free peeling prevention layer. Furthermore, if the product of the specific surface area and the content is 15 or less, the adhesion of the peeling prevention layer to the substrate and electronic components can be ensured, thereby optimizing scratch resistance and peeling prevention.

[0048] BET specific surface area of ​​filler (B) [m² 2 The value of [ / g] is preferably between 0.1 and 150.

[0049] This peeling prevention sheet may contain a flexibility modifier. The flexibility modifier can improve wrinkles and tears during the molding process of the peeling prevention sheet. Examples of flexibility modifiers include plasticizers and inert thermoplastic resins that are not chemically reactive themselves.

[0050] Examples of the aforementioned plasticizers include fatty acid esters, phthalate esters, aromatic polycarboxylic acid esters, and polyesters. Examples of fatty acid esters include trimellityl trioctyl (TOTM), manufactured by Mitsubishi Gas Chemical Trading Co., Ltd., butyl stearate, Unistar M-9676, Unistar M-2222SL, Unistar H-476, Unistar H-476D, Panacete 800B, Panacete 875, Panacete 810 (all manufactured by NOF Corporation), DBA, DIBA, DBS, DOA, DINA, DIDA, DOS, BXA, DOZ, DESU (all manufactured by Daihachi Chemical Co., Ltd.). Examples of phthalate esters include DMP, DEP, DBP, #10, BBP, DOP, DINP, DIDP (all manufactured by Daihachi Chemical Co., Ltd.), PL-200, DOIP (all manufactured by CG Ester Co., Ltd.), and Sansoizer DUP (manufactured by Shin Nippon Rika Co., Ltd.). Examples of aromatic polycarboxylic acid esters include TOTM (manufactured by Daihachi Chemical), Monosizer W-705 (manufactured by Daihachi Chemical), UL-80, and UL-100 (manufactured by ADEKA). Examples of polyesters include Polysizer TD-1720, Polysizer S-2002, Polysizer S-2010 (all manufactured by DIC), and BAA-15 (manufactured by Daihachi Chemical). Among these, DMP, DEP, DBP, DOP, DINP, DIDP, and TOTM are more preferred. The plasticizer may be used alone or in combination of two or more types.

[0051] Examples of the inert 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. While not particularly limited, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, and fluororesins are more preferred from the viewpoint of heat resistance.

[0052] Furthermore, this peeling prevention sheet and peeling prevention layer The material may contain a tackifying resin to improve adhesion to the substrate and electronic components. The tackifying resin is a component that auxiliaryly improves adhesive strength, has a weight-average molecular weight of less than 5,000, and is distinct from the thermoplastic resin and binder mentioned above. Examples of tackifying resins include rosin-based resins, terpene-based resins, alicyclic petroleum resins, and aromatic petroleum resins.

[0053] This peel-preventing sheet 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 dioxide, graphite, and dyes. Examples of UV colorants include fluorescent pigments, fluorescent dyes, and phosphors. 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, paraffin, 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. One or more of these may also be used in combination.

[0054] 《Thickness of the peeling prevention layer: A2》 The thickness A2 of the delamination prevention layer is preferably 5 to 300 μm, from the viewpoint of achieving both delamination prevention (wear resistance, scratch resistance) and thinning of the electronic component, and more preferably 15 to 200 μm. As shown in Figure 2, the above thickness A2 is the measurement value of the thickest part formed on the upper surface region of the electronic component in the cross-sectional image of the electronic component.

[0055] 《Maximum point stress T of the spalling prevention layer》 The maximum point stress T of the delamination prevention layer is a value obtained from a tensile test in accordance with JIS K 7162. Specifically, it is the maximum stress T when a delamination prevention 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 between 1 MPa and 100 MPa, and more preferably between 15 MPa and 40 MPa. When the maximum point stress T is 1 MPa or higher, wear resistance and scratch resistance can be improved. On the other hand, when the maximum point stress T is 100 MPa or lower, the conformability of the delamination prevention sheet to the electronic component is improved when forming a delamination prevention layer on the electronic component. Furthermore, it is possible to suppress defects in appearance and processing, such as the occurrence of gaps between the delamination prevention layer and the substrate, or between the delamination prevention layer and the electronic component, and the increased likelihood of cracking or fracture in the delamination prevention layer, which can lead to delamination of the electronic component or rupture of the delamination prevention layer at corners.

[0056] The maximum point stress T of the delamination prevention layer can be adjusted by selecting a thermoplastic or thermosetting resin, the crosslinking density in the delamination prevention layer, and the selection of fillers. Regarding the crosslinking density, it is preferable to adjust the number and equivalent amounts of functional groups of the curable compound in the composition for forming the delamination prevention layer. Regarding the selection of fillers, the material, shape, size, surface condition, specific surface area, and amount added of the filler can be considered, but it is preferable to select a filler that takes into account the specific surface area and amount added.

[0057] 《Tg of the peeling prevention layer》 The Tg of the delamination prevention layer is a value measured using a dynamic viscoelasticity measuring device. If multiple Tg values ​​for the delamination prevention layer are available, the value with the highest tanδ is used. A Tg of 5°C to 180°C is preferred, and a Tg of 20°C to 80°C is more preferred. By setting the Tg to 5°C to 180°C and adjusting the fluidity of the delamination prevention layer, the delamination prevention layer can be processed into an optimal shape, and the index Y can be set to an optimal range. Furthermore, by setting the Tg to 20°C to 80°C, resistance to frictional heat due to wear and thermal damage during inspection in subsequent processes can be achieved, thereby improving reliability. If the binder (A) contains a thermosetting resin, the maximum point stresses T and Tg refer to those after heat curing.

[0058] 《Anti-peeling sheet》 The peeling prevention sheet is a precursor to the peeling prevention layer. If the peeling prevention sheet contains a thermosetting resin, it becomes a peeling prevention layer by heating it at a predetermined time and temperature to induce a curing reaction. The peeling prevention sheet may have a release sheet on one or both sides for surface protection. In addition, a cushioning material used in the coating protection process with the peeling prevention sheet, described later, may be pre-laminated.

[0059] Method for manufacturing peeling prevention sheets The method for manufacturing the peel-preventing sheet is not particularly limited, but examples include applying a composition obtained by dissolving the binder (A) or other material that forms the peel-preventing layer in a solvent to a release sheet. Examples of application methods include gravure coating, kiss coating, die coating, lip coating, comma coating, blade coating, roll coating, knife coating, spray coating, bar coating, spicoating, and dip coating. Examples include the 3D printing method or various printing methods.

[0060] The peeling prevention sheet of the present invention may be laminated with two or more peeling prevention sheets to achieve a desired thickness. The laminated structure may consist only of peeling prevention sheets, or it may include a layer having a specific function as an intermediate layer.

[0061] Uses of peeling prevention sheets The peeling prevention sheet of the present invention can be suitably used to protect various substrates, such as rigid substrates and FPC substrates, and the electronic components mounted thereon. Furthermore, the anti-peeling sheet of the present invention exhibits practically sufficient adhesion regardless of whether the substrate is metal, resin, fiber, ceramic, glass, or conductive silicone. Suitable metals include aluminum, copper, brass, stainless steel, iron, and chromium. Suitable resins include epoxy resin, polyethylene terephthalate, polyimide, polyamide, polyethylene, polypropylene, polyolefin-based graft polymers, polystyrene, and polyvinyl chloride. Therefore, this anti-peeling sheet can be suitably used for adhesion between dissimilar materials with different polarities.

[0062] Manufacturing method for electronic component-mounted circuit boards This document describes a method for manufacturing circuit boards with electronic components mounted on them. The present invention provides a method for manufacturing an electronic component-mounted substrate, comprising the steps of: mounting one or more electronic components onto the substrate (step i); preparing a peeling prevention sheet (step ii); placing the peeling prevention sheet so that it is in contact with the tallest electronic component among the electronic components (step iii, also called a temporary attachment step); deforming the peeling prevention sheet by heating and pressing to conform to the shape of each electronic component, thereby covering at least a portion of the electronic component and the substrate (step iv); and hardening the deformed peeling prevention sheet in its deformed state to form a peeling prevention layer (step v). This method allows the electronic component-mounted substrate to be covered and protected by a peeling prevention layer formed from the peeling prevention sheet of the present invention. Steps iv and v can also be performed as a series of steps.

[0063] Below, using Figure 3, we will explain an example of a method for protecting an electronic component mounting substrate by heating and pressurizing with a peeling prevention sheet, covering steps iii to v.

[0064] (Step iii; Placement of peeling prevention sheet) A mounting board 100 is prepared on which electronic components 2 are mounted either directly or by solder bumps 4 on a substrate 1. The electronic components 2 can be semiconductor chips, capacitors, transistors, inductors, thermistors, etc., and may be mounted on the substrate 1 via solder bumps 4, and there may be a gap between the electronic components 2 and the substrate 1. Also, the heights of the electronic components 2 may differ. Next, a peel-prevention sheet 6, cut to a predetermined size, is placed on the mounting surface of the electronic component 2. The peel-prevention sheet 6 is temporarily attached in contact with the taller parts of the electronic component 2. Note that the peel-prevention sheet 6 may bend and come into contact with other electronic components 2 (not shown in Figure 3).

[0065] Furthermore, a cushioning material 7 may be laminated onto the peeling prevention sheet 6, and Figure 3 shows an example in which the cushioning material 7 is used. The cushioning material 7 may be laminated after the peeling prevention sheet 6 is placed, or a laminate of the peeling prevention sheet 6 and cushioning material 7 may be placed in advance. The cushioning material 7 is a material that softens or melts when heated or pressurized, and has the function of promoting the peeling prevention sheet 6's ability to conform to the electronic components 2 and to the gaps between electronic components. The cushioning material 7 is not particularly limited as long as it is a thermoplastic material, for example, but it is preferable that it has a melting temperature and glass transition temperature (Tg) lower than the temperature under pressure. Suitable examples include polyolefin films, vinyl chloride films, and PVA films. The groove depth is usually about 100 μm to 1 mm, depending on the groove depth. Multiple layers of cushioning material 7 are laminated. In this case, it is preferable that the total thickness be within this range.

[0066] Furthermore, the electronic component mounting substrate shown in this application is merely an example, and the structure of the electronic component and the substrate is not particularly limited. There may or may not be a gap between the electronic component 2 and the substrate 1. The placement position of the mounted electronic component is not limited.

[0067] (Step iv; Step of coating at least a portion of the electronic components and substrate) Next, by heating and pressurizing with the heating and pressurizing machine 20, the peeling prevention sheet 6 deforms to conform to the shape of the individual electronic components, that is, to conform to the top and side surfaces of the electronic components 2, and to follow at least a part of the group of electronic components and the substrate 1. The cushioning material 7 softens or melts due to the heat, promoting the peeling prevention sheet 6 to conform to the unevenness between the electronic components on the mounting substrate 100. In addition, a method of placing a release sheet between the heating and pressing machine 20 and the cushioning material 7 during heating and pressing is also preferred. The release sheet is a sheet made of a substrate such as paper or plastic that has undergone a known release treatment. Alternatively, a low-polarity plastic sheet such as Teflon (registered trademark) can be used.

[0068] The heating temperature should be such that the peeling prevention sheet 6 softens appropriately, deforms to conform to the shape of individual electronic components, and can penetrate into the gaps between individual electronic components. Preferably, the temperature is 100 to 260°C, and more preferably 120 to 240°C. If the temperature is too low, the ability of the peeling prevention sheet 6 to penetrate into the gaps between the mounted electronic components will decrease. On the other hand, if the temperature is too high, the thermosetting reaction of the thermosetting resin in the peeling prevention sheet 6 will proceed too quickly, reducing the ability of the peeling prevention sheet to penetrate into the gaps between the mounted electronic components. The preferred pressure for heating and pressurizing is 0.01 to 15 MPa, and more preferably 0.1 to 6.0 MPa. Heating and pressurizing at the above pressures improves embedding ability without damaging the electronic components. The heating time is usually 0.5 to 30 minutes, with a range of 1 to 20 minutes being preferable. If the heating time is too short, the ability of the anti-peeling sheet 6 to penetrate between the mounted electronic components will decrease. On the other hand, if the time is too long, thermal decomposition and oxidation of the thermosetting resin are more likely to occur, increasing the possibility of a decrease in the reliability of the adhesive site due to reaction products, etc. The above heating and pressurizing process is preferably carried out under vacuum conditions. In addition to using a heating and pressurizing machine, another preferred method of heating and pressurizing is to stack metal plates of appropriate weight to achieve a predetermined pressure and then place this stacked material into an oven. On the other hand, as a heating and pressurizing method other than a heating and pressurizing machine, vacuum forming or vacuum pressure forming are also preferred.

[0069] (Process v; curing process for deformed peeling prevention sheet) If the peeling prevention sheet 6 contains a thermosetting resin, after heating and pressurizing, the peeling prevention sheet 6 is further heated at a temperature of 150°C to 230°C for 10 to 60 minutes while in a deformed state, thereby thermosetting the thermosetting resin in the peeling prevention sheet 6 and forming the peeling prevention layer 3. The peeling prevention layer adheres firmly to the electronic components and substrate, functioning as a peeling prevention layer to prevent and protect the electronic components from damage caused by external impacts and scratches. Alternatively, the heat curing can be completed and the peeling prevention layer 3 formed by setting the heating and pressurizing temperature to 150°C or higher and the time to 30 minutes or more in step (iv).

[0070] In the electronic component mounting substrate of the present invention, it is preferable that the peeling prevention layer is the outermost layer. Alternatively, other functional layers may be laminated on the inner layer side. These other functional layers may, for example, have properties such as conductivity, hard coating, water vapor barrier properties, oxygen barrier properties, thermal conductivity, low dielectric constant, high dielectric constant, or heat resistance. Among these, a conductive functional layer may be used to protect the coated electronic components from electromagnetic noise.

[0071] For example, Figure 4 shows an example configuration of an electronic component mounting substrate 13 having a conductive functional layer 8 on a peeling prevention layer. The conductive functional layer 8 is formed on top of the peeling prevention layer 3 and connected to a ground 9. The connection point with the ground 9 may be located on the surface of the substrate 1 or on the side surface of the substrate 1. The conductive functional layer 8 can be formed by methods such as forming a metal layer on the surface of the peeling prevention layer 3 by sputtering or plating, or by laminating a conductive metal foil or nonwoven fabric on the peeling prevention layer 3.

[0072] 《Electronic equipment》 The electronic component mounting substrate of the present invention is preferably incorporated into electronic devices such as liquid crystal displays, touch panels, notebook PCs, mobile phones, smartphones, and tablet terminals. [Examples]

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

[0074] 《Raw materials》 The raw materials used in the examples are listed below. <Thermosetting resin> Thermosetting resin (r1): Polyurethane resin (molecular weight (Mw) = 130,000, acid value 10 mg KOH / g, Tg = 20℃), manufactured by Toyo Chem Co., Ltd. Thermosetting resin (r2): Polyurethane resin (molecular weight (Mw) = 125,000, acid value 10 mg KOH / g, Tg = -6℃), manufactured by Toyo Chem Co., Ltd. Thermosetting resin (r3): Acrylic resin (molecular weight (Mw) = 55000, acid value 7 mg KOH / g, Tg = -20℃), manufactured by Toyo Chem Co., Ltd.

[0075] <Curable compound> Curable compound (c1): Tetrad-X tetrafunctional epoxy resin (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 "CERACOL79" (20% non-volatile content), manufactured by BYK.

[0077] <Filler (B)> Filler f1: Carbon black "MA100" (average primary particle size: 24nm, BET specific surface area: 120m²) 2 / g) Manufactured by Mitsubishi Chemical Corporation Filler f2: Silica "UltraSil U360" (Average primary particle size: 28nm, BET specific surface area: 50m²) 2 (Manufactured by NANOCYL Co., Ltd.) Filler f3: Silica "AdmaFine SO-C5" (Average primary particle size: 2.0 μm, BET specific surface area: 2.1 m²) 2 / g), manufactured by Admatex Corporation Filler f4: Plate-shaped boron nitride "HP-1" (average primary particle size: 9.0 μm, BET specific surface area: 3.1 m²) 2 ( / g), manufactured by JFE Mineral Co., Ltd. Filler f5: Silica "Excelica SE-30K" (Average primary particle size: 25.1 μm, BET specific surface area: 0.7 m²) 2 / g) Manufactured by Tokuyama Corporation Filler f6: Flake-shaped silver powder "FA-S-18" (average primary particle size: 3.1 μm, BET specific surface area: 2.0 m²) 2 / g), manufactured by DOWA Corporation Filler f7: Dendritic silver-coated copper powder "ACAX-225M" (average primary particle size: 7.4 μm, BET specific surface area: 0.86 m²) 2 ( / g), manufactured by Mitsui Mining & Smelting Co., Ltd.

[0078] ≪Measurement method≫ <Change in static friction coefficient X during reciprocating wear test> For each example and comparative example, the delamination prevention layer was measured using a test sample consisting of a smooth area of ​​6mm x 6mm or larger on a chip (electronic component) or an electronic component mounting substrate made of molded resin (encapsulating resin) within the resin-containing region beneath the delamination prevention layer. A continuous load surface measuring instrument, HEIDON Tribogear TYPE:22H (manufactured by Shinto Kagaku Co., Ltd.), was used. A thoroughly dried test sample was mounted on the test stand, a 100g load was applied to the friction element, and the static friction coefficient μk was measured at 100 and 300 cycles. 100 , μk 300 The following was recorded. A ball indenter was used as the measuring jig when moving back and forth across the surface of the test sample, and a SUS ball (φ3.0 mm) was used as the friction element. The obtained static friction coefficient μk 100 , μk 300 The change in the static friction coefficient X during the reciprocating wear test was calculated by applying the following [Equation 1]. [Formula 1] X=(μk 300 -μk 100 ) / μk 100 ×100

[0079] <Index Y> As shown in Figure 2, the peeling prevention layer 3 and electronic component mounting substrate 12 of each example and comparative example, prepared by the method described later, were cross-sectioned by polishing, and the radii of curvature R1 and R2 of the curved surfaces at the corners of the electronic components and the covering peeling prevention layer were determined using a digital microscope VHX-7000 (manufactured by Keyence Corporation). Similarly, the thickness A1 of the thinnest part of the corner of the peeling prevention layer (corner thickness of the peeling prevention layer) was determined. For the evaluation of these electronic components and peeling prevention layers, MLCCs with a short side of 0.3 mm and a long side of 0.6 mm (hereinafter also referred to as 0603MLCC, 0603MLCC30) were used. The obtained radii of curvature R1, R2 and corner thickness A1 of the peeling prevention layer were applied to the following [Equation 2] to calculate the index Y. [Formula 2] Y=R2 / (R1+A1)

[0080] <Thickness of the peeling prevention layer A2> The thickness of the delamination prevention layer on the electronic component-mounted substrate was determined by cross-sectioning using a polishing method and observing the thickest point on the top surface of the electronic component using a digital microscope VHX-7000 (Keyence Corporation). Five cross-sectional samples from different electronic component-mounted substrates were measured similarly, and the average value was defined as thickness A2.

[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 images magnified to approximately 50,000 to 1,000,000 times using a transmission electron microscope (TEM). If the particle shape of filler (B) had an average aspect ratio (major axis length / minor axis length) of 1.5 or greater, the average particle size was determined by averaging the major axis lengths.

[0082] <Maximum point stress T of the spalling prevention layer> The peel-resistant sheets with release films for each example and comparative example were heated at 180°C for 2 hours and then cut to a size of 20 mm wide x 60 mm long. Next, the release films were peeled off to obtain measurement samples (peel-resistant layers) made of the peel-resistant sheets. Each measurement sample (peel-resistant layer) was placed in an atmosphere of 100°C (air, 50% RH) from room temperature, and 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 benchtop testing machine EZ-TEST (manufactured by Shimadzu Corporation) with an effective tensile size of 20 x 23 mm, and the maximum stress T (maximum point stress T) at a tensile speed of 50 mm / min was determined.

[0083] <Glass transition temperature Tg> The Tg of the measurement samples (peeling prevention layer) for each example and comparative example was measured using a dynamic viscoelasticity analyzer DVA-200 (manufactured by IT Measurement Control Co., Ltd.) in accordance with JIS K7198. For each example, the peeling prevention layer was cut into 0.5 cm x 3 cm pieces, and the release film was removed. The deformation mode was tensile, and Tg was defined as the temperature at which the main dispersion peak of the loss tangent (tanδ) appeared, measured at a strain of 0.08%, a frequency of 10 Hz, and a heating rate of 10 °C / min. However, in cases where the peeling prevention layer was brittle and fractured during measurement, it was not possible to calculate Tg, and therefore, "unmeasurable" was indicated in the example table.

[0084] 《Preparation of peeling prevention sheet》 [Example 1] According to the types and proportions of ingredients in Table 1, 100 parts of thermosetting resin r1 (solid content), and cured sexual compound c1 is 2.0 parts, and hardened sexual compound c2 10.0 Department and, 0.50 parts of lubricant L1, 2.9 parts of filler f1 and 159 parts of filler f4 were placed in a container, and a mixed solvent of toluene:isopropyl alcohol (mass ratio 2:1) was added to obtain a composition by stirring with a disperser for 10 minutes to achieve a non-volatile content concentration of 45% by mass. This composition was coated onto a release sheet using a doctor blade to achieve a dry thickness of 80 μm. Then, the peel-resistant sheet 6 of Example 1 was obtained by drying at 100°C for 2 minutes.

[0085] [Example 2~ 7、9~13、15、16、18~20 [Comparative Examples 1-4] Laminated sheets for Examples 2-21 and Comparative Examples 1-4 were obtained by the same procedure, except that the types and proportions of materials in Tables 1-2 were changed. The evaluation results for each laminated sheet, described later, are also included. Note that the examples labeled as Example 8, Example 14, Example 17, and Example 21 in Tables 1 and 2 are all for reference only.

[0086] [Creation of Electronic Component Mounting Board 1] (Fabrication of mounting boards) A substrate (mounted substrate) was prepared on a glass epoxy substrate, with 5 x 1 molded electronic components (1 cm x 1 cm) and 8 x 2 arrays of 0603MLCCs (0.6 mm long, 0.3 mm wide) mounted on it. The substrate thickness was 0.6 mm, and the molded encapsulation thickness, i.e., the height H from the top surface of the substrate to the top surface of the molded encapsulation material (component height), was 0.7 mm. The mounting spacing of the 0603MLCCs was 200 μm.

[0087] The laminated sheets of each example and comparative example were heat-pressed onto the above-mentioned mounting substrate at 2 MPa and 180°C for 5 minutes, and the cushioning material was peeled off by hand. After that, the substrates were heated at 180°C for 2 hours to obtain the electronic component mounting substrates of each example and comparative example according to Table 1.

[0088] ≪Rating≫ [Abrasion resistance] For each example and comparative example, the delamination prevention layer was measured on the molded electronic component of the above-mentioned mounted substrate, using the delamination prevention layer on the molded electronic component as the test area. Using a continuous load surface measuring instrument HEIDON Tribogear TYPE:22H (manufactured by Shinto Kagaku Co., Ltd.), a thoroughly dried test sample was mounted on the test stand, a 100g load was applied to the friction element, and after the number of reciprocating cycles specified in the evaluation criteria below, the surface condition of the test sample was observed to check for exposure of the substrate and tearing of the delamination prevention layer (reciprocating abrasion test). If these evaluations were difficult to perform visually, the surface condition was observed at 20x magnification using a digital microscope VHX-7000 (manufactured by Keyence Corporation). A ball indenter was used as the measuring jig when reciprocating across the surface of the test sample, and a SUS ball (φ3.0mm) was used as the friction element. Based on these results, the abrasion resistance was evaluated according to the following criteria. +++: After 500 cycles, the electronic components beneath the peeling prevention layer are not exposed. (Excellent) ++: After 400 cycles, the electronic components beneath the peeling prevention layer are not exposed, but by 500 cycles, they are exposed. (Good) +: After 300 cycles, the electronic components beneath the peeling prevention layer are not exposed, and peeling prevention is maintained by 400 cycles. Electronic components beneath the protective layer were exposed. (Practical level) NG: The electronic components beneath the peel-prevention layer were exposed when the number of back-and-forth cycles was less than 300. (Defective)

[0089] [Peeling prevention] As shown in Figure 5, the edge of a Ni-SUS plate 14 (a commercially available SUS304 plate with a thickness of 0.2 mm and a nickel layer of 2 μm thickness formed on its surface) was applied at a 45° angle to the peeling prevention layer 3 on the corners of the 0603MLCC 30 electronic components 2 on the electronic component mounting substrate created by the method described above, and the plate was flicked from the side of each corner of the 0603MLCC 30 towards the top surface. This was repeated 30 times for each section, and after performing this on the peeling prevention 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 prevention performance (peeling test). In this test, 0603MLCCs that were not covered with a peeling prevention layer peeled off after about 10 tests when the same test was performed. Furthermore, delamination refers to a condition where, compared to before the test, delamination or detachment occurs due to damage between the electronic component-mounted substrate and the electronic component, or between the electronic component-mounted substrate and the delamination prevention layer, resulting in areas where contact between the electronic component-mounted substrate and the electronic component is lost. +++: The number of detached MLCCs is 0. (Excellent condition) ++: The number of detached MLCCs is 1. (Good) +: The number of detached MLCCs is 2 or 3. (Practical level) NG: The number of detached MLCCs is four or more. (Defective)

[0090] [Scratch resistance] A 30mm x 80mm Ni-SUS plate (a commercially available 0.2mm thick SUS304 plate with a 2μm thick nickel layer formed on its surface) was prepared. The anti-peeling sheets (25mm x 70mm) for each example and comparative example were heat-pressed onto this plate at 2MPa and 180°C for 5 minutes, and the cushioning material was peeled off by hand. Afterward, the plate was heated at 180°C for 2 hours to obtain the measurement sample (anti-peeling layer). A scratch test was performed on the measurement sample using a HEIDON Tribogear TYPE:22H (manufactured by Shinto Kagaku Co., Ltd.), a continuous load surface quality measuring instrument, in accordance with JIS K7317. The vertical load at which the anti-peeling sheet coated on the substrate peeled off was continuously measured at 50mm / min. A diamond needle (0.25mmR) was used to scratch the surface of the test sample, and scratch resistance was evaluated according to the following criteria based on the load at which the substrate was exposed from the measurement sample. In terms of scratch resistance, "scratch" refers to a condition where the anti-exfoliation layer peels off due to tearing or stretching when the tip of a scratching jig scratches the layer, exposing the base material. It does not refer to needle marks, which can easily vary in results depending on the observer. +++: Vertical load when the substrate is exposed ≥ 350g (Excellent) ++:350g> Vertical load when the substrate is exposed ≥250g. (Good) +:250g > Vertical load ≥ 200g when the base material is exposed. (Practical) NG: 200g > Vertical load when the base material is exposed. (Defective)

[0091] [Reliability] A molded resin substrate (60 mm x 50 mm) was prepared, and the anti-peeling sheets (55 mm x 45 mm) for each example and comparative example were heat-pressed onto them at 2 MPa and 180°C for 5 minutes, and the cushioning material was peeled off by hand. After that, the substrate was heated at 180°C for 2 hours to obtain the measurement sample (anti-peeling layer). Using a cross-cut guide in accordance with JIS K5600, 25 grid lines with 1 mm spacing were created on the anti-peeling layer surface of the electronic component, and then adhesive tape was pressed onto it. The end of the tape was then 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 condition of the peel-preventing layer remaining on the molded resin substrate (cross-cut) The survival rate was evaluated according to the following criteria. +++: Indicates a cross-cut survival rate of 100 / 100. (Excellent) ++: Indicates a cross-cut survival rate of 95-99 / 100. (Good) +: Indicates a cross-cut survival rate of 80-94 / 100. (Practical) NG: The remaining percentage is less than 80 / 100. (Defective) Except for the changes in the content, thickness Ta, and protective film shown in Tables 2-5, this example is the same as Example 1. Sealing sheets were prepared using the specified method and evaluated similarly. Note that all crosslinking agents, oligomers, monomers, polymerization initiators, and other components were added simultaneously.

[0092] [Table 1]

[0093] [Table 2]

[0094] As shown in Comparative Example 1 or 2, peeling prevention layers with a static friction coefficient change rate X of less than -50% or greater than 200% were found to have problems with wear resistance and peeling prevention. Peeling prevention layers with an index Y of less than 0.8 or greater than 20.0 were found to have problems with peeling prevention, as shown in Comparative Example 3 or 4. In contrast to the above, The peeling prevention layer of this embodiment, which satisfies all of claims 1(1) and (2), has been confirmed to be excellent in terms of abrasion resistance, peeling prevention, scratch resistance, and reliability. [Explanation of symbols]

[0095] (Explanation of the diagram) 1: Circuit board 2: Electronic components 3: Anti-peeling layer 4: Handa Bump 5:Hollow part 6: Anti-peeling sheet 7: Cushioning material 8: Functional Layer 9: Grand 10: Electronic component mounted circuit board 11: Electronic component mounted circuit board 12: Electronic component mounting substrate with functional layer 13:Ni-SUS board 20:Heating and pressure machine 30:0603MLCC 100: Implemented circuit board

Claims

1. A peeling prevention sheet, which is a precursor to the peeling prevention layer in an electronic component mounting substrate comprising a substrate, an electronic component mounted on at least one surface of the substrate, and a peeling prevention layer covering the substrate and the electronic component, comprises a binder (A) and a filler (B), wherein the binder (A) comprises a thermosetting resin and a bifunctional curable compound, with 5 to 50 parts by mass of the bifunctional curable compound per 100 parts by mass of the thermosetting resin, the content of the filler (B) in 100% by mass of the peeling prevention sheet is 1 to 55% by mass, the product of the BET specific surface area [m² / g] of the filler (B) and the content [mass%] of the filler (B) in 100% by mass of the peeling prevention sheet is 0.01 to 15 [mass%・m² / g], and the peeling prevention layer conforms to JIS K A peeling prevention sheet in which the maximum point stress T obtained in a tensile test compliant with 7162 is between 13 MPa and 100 MPa.

2. The peeling prevention sheet according to claim 1, wherein the glass transition temperature Tg of the peeling prevention layer obtained by dynamic viscoelasticity measurement in accordance with JIS K7198 is 5°C or more and 180°C or less.

3. A peeling prevention layer for an electronic component mounting substrate, comprising a substrate, an electronic component mounted on at least one surface of the substrate, and a peeling prevention layer covering the substrate and the electronic component, wherein the peeling prevention layer comprises a binder (A) and a filler (B), the content of the filler (B) in 100% by mass of the peeling prevention layer is 1 to 55% by mass, the product of the BET specific surface area [m² / g] of the filler (B) and the content of the filler (B) in 100% by mass of the peeling prevention layer [mass%] is 0.01 to 15 [mass%・m² / g], and the maximum point stress T obtained in a tensile test of the peeling prevention layer in accordance with JIS K 7162 is 13 MPa or more and 100 MPa or less.

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