Electronic component mounting substrate and electronic equipment

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 relates to an electronic component mounting substrate and an electronic device.

Background Art

[0002] Terminal-based electronic devices such as smartphones and wearable devices are used in a variety of environments, so high reliability is required to prevent malfunction even under harsh conditions. Furthermore, with the progress of miniaturization and thinning of electronic devices, the size of the electronic component mounting substrate used has also been reduced, and the contact area between the substrate and the electronic components has also been reduced. Along with this, the adhesion between the electronic components and the substrate has decreased, causing the electronic components to peel off from the substrate. Against this background, there is an increasing need to prevent damage and slipping of electronic components from physical damage, heat, and humidity. Therefore, a method of protecting electronic components from external damage by embedding electronic components such as IC chips and MLCCs (multi-layer ceramic capacitors) with a resin layer is known (Patent Document 1). However, from the viewpoints of reducing the thickness of the electronic component mounting substrate and cost reduction, formation of a protective layer that is thinner and has a reduced thickness after processing is required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, an invention related to a coated and protected electronic component mounting substrate has been disclosed. However, when the protective layer is made thinner, many problems described below occur, and an electronic component mounting substrate that can solve these problems at once is desired.

[0005] In the process of assembling an electronic device, there are several work steps of mounting various electronic components on a substrate using solder or an adhesive, with intervening steps. After mounting the electronic components on the substrate, steps such as assembling the electronic device and performing reliability tests are carried out. During such operations, peeling or displacement of the substrate may occur due to the snagging of human fingernails or other components on the mounted electronic components. In recent years, the miniaturization and low-profile of electronic components such as multilayer ceramic capacitors (hereinafter referred to as MLCCs) have advanced rapidly. Along with this, the contact area with the substrate has become smaller, resulting in a decrease in the adhesion between the component and the substrate, and the importance of preventing peeling of the above-mentioned electronic components has become even higher.

[0006] Also, even when there is contact or rubbing between a hard member such as metal and an electronic component, a protective member having abrasion resistance and scratch resistance that can withstand it is required. Furthermore, a highly reliable electronic component mounting substrate is required in which the protective member does not peel off even when used for a long time in a high-temperature and high-humidity environment.

[0007] An object of the present invention is to provide a highly reliable electronic component mounting substrate that is excellent in abrasion resistance and scratch resistance, in which electronic components are not easily peeled off due to external damage, and can be used for a long time under high temperature and high humidity, even in a miniaturized and low-profile electronic component mounting substrate.

Means for Solving the Problems

[0008] As a result of intensive studies, the present inventors have found that by using an article (electronic component mounting substrate, peeling prevention layer, and peeling prevention sheet) having the following characteristics, the above problems can be solved, and the present invention has been completed. That is, the present invention relates to an electronic component mounting substrate, a peeling prevention layer, and a peeling prevention sheet, which are characterized as follows. [1]: A substrate, electronic components mounted on at least one surface of the substrate, and a peeling prevention layer covering the substrate and the electronic components, wherein the peeling prevention layer satisfies all of (1) and (2), and is an electronic component mounting substrate. (1) The change rate X of the static friction coefficient, obtained by the following [Formula 1], is -50% or more and 200% or less. 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.

Effect 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

Figure 2

Figure 3

Figure 4

Figure 5

Mode 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, a build-up board formed by a build-up method, etc. in which a conductive pattern made of copper foil or the like is formed on the surface and / or inside. A build-up substrate formed by the above can be mentioned.

[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 which the present invention is applied because their miniaturization is progressing.

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

[0016] The size and height of the electronic component 2 are not particularly limited. However, due to the recent trend of miniaturization and low profile, the height is preferably 3 mm or less. The shape of the IC chip may be rectangular, cylindrical, coin type, thin film type, etc., in addition to rectangular. For MLCC, the mainstream package sizes of 0402 (length 0.4 mm, width 0.2 mm) and 0603 (length 0.6 mm, width 0.3 mm) are preferred, but other larger ones such as 1005 and 1608 may also be mounted. The shape of the inductor includes solenoid, dome type coil, flat type coil, etc. The thermistor includes rectangular, cylindrical, lead type, etc. for surface mounting.

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

[0018] The peeling prevention layer 3 may cover and protect the electronic component 2 and the substrate 1 so as to maintain the hollow portion 5, or may cover and protect so as to fill 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 FIG. 1, it covers from the upper surface to the side surface of the electronic component 2, and further extends over the entire surface or a part of the end surface of the substrate 1. That is, the coating layer 3 is provided so as to follow the stepped portion (concavo-convex portion) formed by mounting 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 the present peeling prevention sheet is not limited, but any one of a press forming method, a TOM (Three dimension Overlay Method) forming method which is a three-dimensional surface coating method, a vacuum forming method, a pneumatic forming method, a vacuum pneumatic forming method, and an injection molding method is suitable. Among these, the present peeling prevention sheet is particularly suitable for the press forming method.

[0020] In the example of FIG. 1, an example of mounting the electronic component 2 on one surface of the substrate 1 has been described, but the electronic component 2 may be mounted on both surfaces of the substrate, and both surfaces of the substrate may be covered with the peeling prevention layer.

[0021] 《Peeling Prevention Layer》 Next, the peeling prevention layer of the present invention will be described in more detail. The peeling prevention layer is for preventing the electronic component group arranged on the substrate from peeling off from the mounting substrate as described above.

[0022] The peeling prevention layer satisfies all of the following (1) and (2). (1) The change rate X of the static friction coefficient, which is obtained by the following formula 1, is -50% or more and 200% or less. (2) The exponent Y, which is obtained by the following formula 2, is 0.8 or more and 20.0 or less. Note that these numerical values X and Y are values calculated by the following [Formula 1] and [Formula 2], and X , The measurement of Y follows the methods and conditions described in the examples respectively.

[0023] 《Change Rate X of Static Friction Coefficient》 The change rate X of the static friction coefficient obtained by the reciprocating wear test of the peeling prevention layer (hereinafter, the change rate X of the static friction coefficient) can be expressed by the following [Formula 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 judging the presence or absence of wear resistance. Therefore, the coefficient of static friction μk at the 100th time 100 and the coefficient of static friction μk at the 300th time, which is an index for the presence or absence of wear resistance 300 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 scratched, 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 substrate from the viewpoint of obtaining stable measurement values. The resin region refers to a portion 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] [Method of Control] As the method for controlling the change rate X of the coefficient of static friction of the anti-peeling layer, any method can be applied, including conventionally known methods. For example, a method of improving the resistance to friction by hardening the surface of the anti-peeling layer by adjusting the compounding components, a method of improving the slipperiness of the oil replenishing surface by adding a wax component or the like to the anti-peeling layer, a method of reducing the surface unevenness by reducing the amount or changing the shape of the particulate components to be added (reduction of the surface coefficient of friction), a method of increasing the heat resistance of the anti-peeling layer, and a method of reducing the surface unevenness depending on the type of the protective film used when forming the anti-peeling sheet, which is a precursor of the anti-peeling layer, on the electronic component mounting substrate. The method for controlling the abrasion resistance of the surface of the anti-peeling layer is not limited to the exemplified methods, but from the viewpoint of productivity, a method of increasing the amount of the curing agent in the anti-peeling layer to harden the surface or a method of adjusting the amount and shape of the particulate matter in the anti-peeling layer to reduce the surface unevenness is preferable because there is no need to perform special pre- or post-treatment.

[0029] 《Index Y》 In the anti-peeling layer of the present invention, the index Y obtained by the following [Formula 2] is 0.8 or more and 20.0 or less. By setting the above numerical range, an appropriate shape for smoothly covering the surface of the electronic component mounting substrate and preventing the peeling of the electronic components can be obtained. From the viewpoints of the uniformity of the anti-peeling layer thickness (followability to the components) and ensuring the thickness at the corners of the electronic components, 0.9 or more and 12.0 are preferable, and 1.0 or more and 5.0 or less are more preferable. Y = R 2 / (R 1 + A 1 ) [Formula 2] In addition, R 2 , R 1 , A 1 in [Formula 2] are obtained from the measured values of the cross section when the electronic component mounting substrate shown in FIG. 2 is cut perpendicular to the substrate surface, and 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 is R 1 , and the radius of curvature of the corner of the anti-peeling layer in the cross section of the electronic component mounting substrate mounted thereon is R 2, the corner thickness A of the peeling prevention layer in the cross-section of the electronic component mounting substrate 1 (hereinafter referred to as the corner thickness A of the peeling prevention layer 1 ) shall be used. The cross-section of the electronic component mounting substrate is cross-sectioned using dicing or polishing methods, and the cross-section is measured for length measurement using, for example, a digital microscope VHX-7000 (manufactured by Keyence Corporation) to obtain R 2 , R 1 , A 1 can be obtained. Note that the radius of curvature R 1 and R 2 indicate the most likely snagging locations at each corner, and refer to the radius of curvature that becomes the minimum value during measurement at each corner.

[0030] The index Y is a value representing the change in smoothness between the corner of the electronic component and the corner of the peeling prevention layer on the electronic component. By setting the index Y within the above range, peeling of the electronic component due to snagging between the electronic component and claws or other components that occurs during inspection of the electronic component mounting substrate or when mounting the electronic component mounting substrate to an electronic device in subsequent processes can be prevented.

[0031] The index Y can be controlled by adjusting the followability and fluidity of the peeling prevention sheet with respect to the electronic component during processing. Specifically, methods of adjustment by selecting the binder (A) and filler (B) that constitute the peeling prevention sheet described later, methods of adjusting the followability of the peeling prevention sheet to the substrate and electronic component by adjusting the processing conditions (processing temperature, processing time, pressure conditions, degree of vacuum, etc.) during peeling prevention sheet processing, and methods of controlling the fluidity of the peeling prevention sheet by changing the laminated structure during peeling prevention sheet processing can be mentioned. Different methods can be applied respectively, or common methods can be applied.

[0032] 《Binder (A)》 The peeling prevention layer contains a binder (A). The binder (A) serves as the base of the peeling prevention layer and has the function of supporting the filler (B) and other optional components described later. The binder (A) can use either a thermoplastic resin or a thermosetting resin and a curable compound.

[0033] [Thermoplastic resin] Examples of the 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, fluororesins, etc. 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 preferable. The thermoplastic resin can be used alone or in combination of two or more.

[0034] [Thermosetting resin] The thermosetting resin is a resin having a plurality of functional groups capable of reacting with a curing compound. Examples of the functional group include a hydroxyl group, a phenolic hydroxyl group, an acid anhydride group, a methoxymethyl group, a carboxyl group, an amino group, an epoxy group, an oxetanyl group, an oxazoline group, an oxazine group, an aziridine group, a thiol group, an isocyanate group, a blocked isocyanate group, a blocked carboxyl group, a silanol group, etc. Examples of the thermosetting resin include acrylic resins, maleic resins, polybutadiene resins, polyester resins, polyurethane resins, polyurethane-urea resins, epoxy resins, oxetane resins, phenoxy resins, polyimide resins, poly Known resins such as amide resins, polyamide-imide resins, phenolic resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, and fluororesins are included. The thermosetting resin can be used alone or in combination of two or more.

[0035] Among these, from the viewpoint of heat resistance, polyurethane resins, polyurethane-urea resins, polyester resins, epoxy resins, phenoxy resins, polyimide resins, polyamide resins, and polyamide-imide resins are preferable.

[0036] [Curing 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, phenol compounds, and organometallic compounds. The curable compounds can be used alone or in combination of two or more.

[0037] The curable compound preferably has two or more functional groups, and more preferably contains a curable compound having three or more functional groups. From the viewpoint of adjusting the crosslinking density and achieving both proper processing during the molding of the electronic component mounting substrate described later and the temporal stability of the composition which is the precursor of the peeling prevention sheet, it is desirable to use a difunctional curable compound and a curable compound having three or more functional groups in combination. It can also be adjusted by the content of the curable compound in the composition. By adjusting the content of the curable compound as described later, a strong crosslinked structure is formed in the peeling prevention layer, the adhesion between the peeling prevention layer and the base material is increased, and the reliability is improved.

[0038] The difunctional curable compound preferably contains 1 to 50 parts by mass, more preferably 15 to 30 parts by mass, per 100 parts by mass of the thermosetting resin. By setting the amount of the difunctional curable compound to 1 part by mass or more, a strong crosslinked structure is formed in the peeling prevention layer, improving the resistance to thermal damage. Further, by setting it to 15 parts by mass or more, the surface hardness and strength of the peeling prevention layer can be adjusted, and the abrasion resistance can be improved. On the other hand, by setting the amount of the curable compound to 50 parts by mass or less, excessive curing of the peeling prevention layer is suppressed, and cracking due to shrinkage after curing of the peeling prevention sheet is suppressed.

[0039] The curable compound having three or more functional groups is preferably contained in an amount of 0.2 to 20 parts by mass, more preferably 0.3 to 5 parts by mass, and still more preferably 0.8 to 3 parts by mass with respect to 100 parts by mass of the thermosetting resin. By being 0.8 parts by mass or more, the adhesion between the peeling prevention layer and the base material can be increased, and the reliability can be improved. Further, when the curable compound having three or more functional groups is 5 parts by mass or less, in the manufacturing process of the electronic component mounting substrate described later, the peeling prevention sheet 6 deforms following the shape of the electronic component during heating and pressurization, and a peeling prevention layer without defects can be formed.

[0040] [Lubricant] This peeling prevention layer may contain a lubricant such as wax. By adding these, the slipperiness of the surface of the peeling prevention layer can be increased, and the abrasion resistance can be improved. An improvement in reliability can also be expected to make the surface of the peeling prevention layer less likely to crack. For example, as wax, animal and plant waxes such as beeswax, lanolin wax, spermaceti wax, candelilla wax, carnauba wax, rice wax, wood wax, jojoba oil, palm oil; mineral and petroleum waxes such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, petrolatum; synthetic waxes such as Fischer-Tropsch wax, polyethylene wax, oxidized polyethylene wax, oxidized polypropylene wax, montan wax derivatives, paraffin wax derivatives, microcrystalline wax derivatives, Teflon (registered trademark) wax , and the like can be mentioned.

[0041] 《Filler (B)》 The peeling prevention layer contains a filler (B). By appropriately changing the type, average particle diameter, and addition amount of the filler (B), the change rate X of the index Y and the coefficient of static friction can be controlled. Further, the cohesive force in the peeling prevention layer can be adjusted, and mechanical properties such as the maximum point stress T can be made within a good 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 appropriately selected. For example, flake-shaped, needle-shaped, spherical, dendrite-shaped, and fibrous fillers can be mentioned. Fillers with different shapes may be used in combination. Preferred examples include a combination of spherical fillers with an average particle size difference of 10 times or more, and a combination of flake-shaped fillers and dendrite-shaped fillers.

[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, and ceramics. The insulating filler is used alone or in combination of two or more.

[0043] Examples of the conductive filler can include metal fillers, conductive ceramic fillers, and mixtures thereof. Examples of the metal filler can include metal powders such as gold, silver, copper, and nickel, alloy powders such as solder, 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, a conductive filler containing silver is preferable. From the viewpoint of cost, silver-coated copper powder is particularly preferable.

[0044] Examples of the electromagnetic wave absorbing filler can 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-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 can include fillers composed of acetylene black, ketjen black, furnace black, carbon black, carbon fiber, carbon nanotube, graphene filler, graphite filler, and carbon nanowall.

[0045] The average particle diameter of the filler (B) is preferably 0.005 to 50 μm. From the viewpoint of maintaining the smoothness of the surface of the anti-peeling layer, reducing the influence of wear powder during wear, and improving the wear resistance, 0.02 to 20 μm is more preferable.

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

[0047] The product of the BET specific surface area [m 2 / g] of the filler (B) in the anti-peeling layer and the content [% by mass] in 100% by mass of the anti-peeling layer (hereinafter referred to as the product of the specific surface area and the content) is preferably 0.01 to 15, and more preferably 0.1 to 10. When two or more types of fillers (B) are used, the product of the specific surface area and the content is the sum of the products of the specific surface area and the content obtained for each type of filler (B) contained in the anti-peeling layer. 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 anti-peeling sheet. Therefore, in the manufacturing process of the electronic component mounting substrate described later, breakage of the anti-peeling sheet 6 during heating and pressurization can be prevented, and an anti-peeling layer without defects can be formed. Further, when the product of the specific surface area and the content is 15 or less, the scratch resistance and the anti-peeling property can be optimized by ensuring the adhesion of the anti-peeling layer to the base material and the electronic component.

[0048] The BET specific surface area [m 2 / g] of the filler (B) is preferably 0.1 to 150.

[0049] This anti-peeling sheet may contain a flexibility modifier. The flexibility modifier can improve wrinkles and tears during the forming process of the anti-peeling sheet. Examples of the flexibility modifier include plasticizers and inert thermoplastic resins that are scientifically non-reactive themselves.

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

[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. 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 preferable.

[0052] Furthermore, the anti-peeling sheet may contain an adhesion-imparting resin to improve the adhesion to the substrate and electronic components. The adhesion-imparting resin is a component that auxiliary improves the adhesive force, has a weight-average molecular weight of less than 5,000, and is distinguished from the above-mentioned thermoplastic resin and binder. Examples of the adhesion-imparting resin include rosin-based resins, terpene-based resins, alicyclic petroleum resins, and aromatic petroleum resins.

[0053] The anti-peeling sheet may further contain a colorant, a UV colorant, a flame retardant, a lubricant, an anti-blocking agent, etc. Examples of the colorant include organic pigments, carbon black, ultramarine, bengal rose, zinc white, titanium oxide, graphite, and dyes. Examples of the UV colorant include fluorescent pigments, fluorescent dyes, phosphors, etc. Examples of the flame retardant include halogen-containing flame retardants, phosphorus-containing flame retardants, nitrogen-containing flame retardants, inorganic flame retardants, etc. Examples of the lubricant include fatty acid esters, hydrocarbon resins, paraffin, higher fatty acids, fatty acid amides, aliphatic alcohols, metal soaps, modified silicones, etc. Examples of the anti-blocking agent include calcium carbonate, silica, polymethylsilsesquioxane, aluminum silicate salts, etc. Also, one or more of these may be used in combination.

[0054] 《Thickness A of the anti-peeling layer 2 》 Thickness A of the anti-peeling layer 2 is preferably 5 to 300 μm, more preferably 15 to 200 μm, from the viewpoint of achieving both anti-peeling properties (abrasion resistance, scratch resistance) and thinning of the electronic components. Note that, as shown in FIG. 2, the above thickness A 2 is the measured value at the thickest point formed in the upper surface region of the electronic component in the cross-sectional image of the electronic component.

[0055] 《Maximum point stress T of the anti-peeling layer》 The maximum point stress T of the peeling prevention layer is a value obtained from a tensile test in accordance with JIS K 7162. Specifically, it is the stress T at the maximum when the peeling prevention layer with an effective tensile size of 20×23 mm is pulled at 50 mm / min in an atmosphere of 100°C (in 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, the abrasion resistance and scratch resistance can be improved. On the other hand, when the maximum point stress T is 100 MPa or less, when forming the peeling prevention layer on the electronic component, the followability of the peeling prevention sheet to the electronic component is improved. Furthermore, since the generation of voids between the peeling prevention layer and the substrate or between the peeling prevention layer and the electronic component, and cracks and cracks in the peeling prevention layer are likely to occur, peeling of the electronic component and breakage of the peeling prevention layer at the corners can be suppressed, and defects in appearance and processing can be suppressed.

[0056] The maximum point stress T of the peeling prevention layer can be adjusted by the selection of a thermoplastic resin or a thermosetting resin, the crosslink density in the peeling prevention layer, and the selection of the filler. Regarding the crosslink density, a method of adjusting the functional group number and equivalent of the curable compound in the composition for forming the peeling prevention layer is suitable. Regarding the selection of the filler, it can be selected from factors such as the material, shape, size, surface state, specific surface area, and addition amount of the filler, but a selection considering the specific surface area and addition amount of the filler is suitable.

[0057] 《Tg of the peeling prevention layer》 The Tg of the peeling prevention layer is a value measured using a dynamic viscoelasticity measuring device. When multiple Tgs of the peeling prevention layer can be confirmed, the value showing the highest tanδ shall be used. It is preferably 5°C or more and 180°C or less, and more preferably 20°C or more and 80°C or less. By adjusting the fluidity of the peeling prevention layer by setting the Tg to 5°C or more and 180°C or less, the peeling prevention layer can be processed into an optimal shape, and the index Y can be set within an optimal range. Also, by setting the Tg to 20°C or more and 80°C or less, resistance to frictional heat due to abrasion and thermal damage in inspections in subsequent processes can be achieved simultaneously, and reliability can be improved. When the binder (A) contains a thermosetting resin, the maximum point stress T and Tg refer to those after heat curing.

[0058] 《Anti-peeling sheet》 The anti-peeling sheet is a precursor of the anti-peeling layer. When the anti-peeling sheet contains a thermosetting resin, the anti-peeling sheet is heated at a temperature for a predetermined time or more to cause a curing reaction, thereby becoming the anti-peeling layer. The anti-peeling sheet may be provided with a release sheet on one side or both sides for surface protection. Further, a cushioning material used in the coating protection step by the anti-peeling sheet described later may be laminated in advance.

[0059] 《Manufacturing method of anti-peeling sheet》 The manufacturing method of the anti-peeling sheet is not particularly limited. For example, a method of applying a composition in which a material such as the above binder (A) for forming the anti-peeling layer is dissolved in a solvent or the like to a release sheet can be mentioned. As the coating method, for example, a gravure coating method, a kiss coating method, a die coating method, a lip coating method, a comma coating method, a blade coating method, a roll coating method, a knife coating method, a spray coating method, a bar coating method, a spin coating method, a dip coating method, or various printing methods can be mentioned. -ting method, or various printing methods and the like can be mentioned.

[0060] The anti-peeling sheet of the present invention may be laminated with two or more anti-peeling sheets to achieve a desired thickness. Regarding the composition laminated as described above, it may be composed only of the anti-peeling sheet, or may include a layer having a specific function as an intermediate layer.

[0061] 《Uses of anti-peeling sheet》 The anti-peeling sheet of the present invention can be suitably used for protecting various substrates, that is, various substrates such as rigid substrates and FPC substrates, and electronic components mounted thereon. In addition, the anti-peeling sheet of the present invention exhibits practically sufficient adhesion regardless of whether the substrate is made of metal, resin, fiber, ceramic, glass, or conductive silicone. As the metal, it can be used for aluminum, copper, brass, stainless steel, iron, chromium, etc. As the resin, it can be used for epoxy resin, polyethylene terephthalate, polyimide, polyamide, polyethylene, polypropylene, polyolefin-based graft polymer, polystyrene, polyvinyl chloride, etc. Therefore, this anti-peeling sheet can also be suitably used for adhesion between dissimilar materials with different polarities.

[0062] 《Method for Manufacturing an Electronic Component Mounting Substrate》 The method for manufacturing an electronic component mounting substrate will be described. The method for manufacturing an electronic component mounting substrate of the present invention includes a step of mounting one or more electronic components on a substrate (step i), a step of preparing an anti-peeling sheet (step ii), and a step of placing the anti-peeling sheet so that it contacts the tallest electronic component among the electronic components (step iii, also referred to as a temporary tensioning step). By heating and pressurizing, the anti-peeling sheet is deformed along the shape of each electronic component, and at least a part of the electronic component and the substrate is coated (step iv). The deformed anti-peeling sheet is cured in the deformed state to form an anti-peeling layer (step v). Thus, the electronic component mounting substrate can be coated and protected by the anti-peeling layer formed from the anti-peeling sheet of the present invention. Step iv and step v can also be a series of steps.

[0063] Hereinafter, an example of a method for coating and protecting an electronic component mounting substrate by heating and pressurizing using an anti-peeling sheet will be described with reference to FIG. 3 for steps iii to v.

[0064] (Step iii; Anti-peeling Sheet Placement Step) Prepare a mounting substrate 100 in which electronic components 2 are mounted on a substrate 1 directly or via solder bumps 4. The electronic components 2 are 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 respective electronic components 2 may be different. Next, place a peeling prevention sheet 6 cut to a predetermined size on the mounting surface of the electronic component 2. The peeling prevention sheet 6 comes into contact with and is temporarily adhered to the electronic component 2 having a height. Note that the peeling prevention sheet 6 may bend and come into contact with other electronic components 2 (not shown in FIG. 3).

[0065] In addition, a cushion material 7 may be laminated on the peeling prevention sheet 6, and FIG. 3 shows an example using the cushion material 7. The cushion material 7 may be laminated after placing the peeling prevention sheet 6, or a laminate in which the peeling prevention sheet 6 and the cushion material 7 are overlapped in advance may be placed. The above cushion material 7 is a material that softens or melts during heating and pressurization, and has a function of promoting the followability of the peeling prevention sheet 6 to the electronic component 2 and to the gaps between the electronic components. The cushion material 7 is not particularly limited as long as it is a material having, for example, thermoplasticity, but preferably has a melting temperature and a glass transition point (Tg) lower than the temperature during pressurization. Preferred examples include polyolefin-based films, vinyl chloride films, and PVA films. Although it depends on the depth of the groove, it is usually about 100 μm to 1 mm. When laminating a plurality of cushion materials 7 it is preferable that the total thickness is within this range.

[0066] In addition, the electronic component mounting substrate shown in the present application is an example, and the structure of the electronic component and the substrate is not particularly limited, and there may or may not be a gap between the electronic component 2 and the substrate 1. The arrangement position of the electronic components to be mounted is not limited.

[0067] (Step iv; Step of covering at least a part of the electronic component and the substrate) Next, by performing heating and pressing with the heating and pressing machine 20, the peeling prevention sheet 6 is deformed so as to conform to the shape of each electronic component, that is, deformed along the upper surface and the side surface of the electronic component 2, and follows at least a part of the electronic component group and the substrate 1. The cushioning material 7 is softened or melted by heat to facilitate following the unevenness between the electronic components on the mounting substrate 100 of the peeling prevention sheet 6. A method of interposing a release sheet between the heating and pressing machine 20 and the cushioning material 7 during heating and pressing is also preferable. The release sheet is a sheet obtained by performing a known release treatment on a base material such as paper or plastic. Also, a plastic sheet with low polarity such as Teflon (registered trademark) can be used.

[0068] The heating temperature may be a temperature at which the peeling prevention sheet 6 is moderately softened, deformed along the shape of each electronic component, and can enter the gap between the individual electronic components, preferably 100 to 260°C, more preferably 120 to 240°C. If the temperature is too low, the ability of the peeling prevention sheet 6 to enter the gap between the mounted individual electronic components decreases. On the other hand, if the temperature is too high, the thermosetting reaction of the thermosetting resin of the peeling prevention sheet 6 proceeds rapidly, and the ability of the peeling prevention sheet to enter between the mounted electronic components decreases. The pressure during heating and pressing is preferably 0.01 to 15 MPa, more preferably 0.1 to 6.0 MPa. By heating and pressing at the above pressure, the embedding property is further improved without damaging the electronic components. The heating time is usually 0.5 to 30 minutes, preferably in the range of 1 to 20 minutes. If the heating time is too short, the ability of the peeling prevention sheet 6 to enter between the mounted electronic components decreases. On the other hand, if the time is too long, thermal decomposition and oxidation of the thermosetting resin are likely to occur, increasing the possibility of a decrease in the reliability of the bonding site due to reaction products and the like. The above heating and pressing process is preferably performed in a vacuum state. As a method of heating and pressing, in addition to using a heating and pressing machine, a method of laminating metal plates of appropriate weight to obtain a predetermined pressure and putting this laminate into an oven is also preferable. On the other hand, as a heating and pressing method other than the heating and pressing machine, vacuum forming or vacuum pressure forming is also preferable.

[0069] (Step v; Curing process of the deformed anti-peeling sheet) When the anti-peeling sheet 6 contains a thermosetting resin, after heating and pressing, in the deformed state of the anti-peeling sheet 6, it is further heated at a temperature of 150°C to 230°C for 10 minutes to 60 minutes, so that the thermosetting resin in the anti-peeling sheet 6 is thermoset to form the anti-peeling layer 3. The anti-peeling layer adheres firmly to the electronic component and the substrate, and functions as an anti-peeling layer for preventing damage to the electronic component from external impact and scratches. In addition, by setting the temperature of heating and pressing to 150°C or higher and the time to 30 minutes or longer at the stage of (Step iv), the thermosetting can be completed to form the anti-peeling layer 3.

[0070] It is preferable that the anti-peeling layer is the outermost layer in the electronic component mounting substrate of the present invention. Also, other functional layers may be laminated on the inner layer side. The other functional layer is, for example, a layer having functions such as conductivity, hard coat property, water vapor barrier property, oxygen barrier property, heat conductivity, low dielectric constant, high dielectric constant property, or heat resistance. Among them, the functional layer having conductivity may be used for the purpose of protecting the electronic component to be coated and protected from electromagnetic wave noise.

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

[0072] 《Electronic device》 The electronic component mounting substrate of the present invention is preferably provided in electronic devices such as liquid crystal displays, touch panels, as well as notebook PCs, mobile phones, smartphones, tablet terminals, etc.

Example

[0073] Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited only to the following Examples. In 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 shown below. <Thermosetting Resin> Thermosetting resin (r1): Polyurethane resin (molecular weight (Mw) = 130,000, acid value 10 mgKOH / g, Tg = 20°C), manufactured by Toyochem Co., Ltd. Thermosetting resin (r2): Polyurethane resin (molecular weight (Mw) = 125,000, acid value 10 mgKOH / g, Tg = -6°C), manufactured by Toyochem Co., Ltd. Thermosetting resin (r3): Acrylic resin (molecular weight (Mw) = 55,000, acid value 7 mgKOH / g, Tg = -20°C), manufactured by Toyochem Co., Ltd.

[0075] <Curing Compound> Curing compound (c1): Tetrafunctional epoxy resin "TETRAD-X" (epoxy equivalent = 100 / eq), manufactured by Mitsubishi Chemical Corporation Curing compound (c2): Bifunctional epoxy resin "jER828" (epoxy equivalent = 189 g / eq), manufactured by Mitsubishi Chemical Corporation Curing 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" (non-volatile content 20%), manufactured by BYK

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

[0078] <<Measurement method>> <Rate of change X of the coefficient of static friction during the reciprocating wear test> For the anti-peeling layers of each example and comparative example, the smooth portion of 6 mm × 6 mm or more on the chip (electronic component) made of mold resin (sealing resin) or the electronic component mounting substrate under the anti-peeling layer was used as a test sample for measurement. Using a continuous loading type surface property measuring machine HEIDON Tribogear TYPE: 22H (manufactured by Shinto Kagaku Co., Ltd.), a sufficiently dried test sample was attached on the test bench, a load of 100 g was applied to the friction element, and the coefficients of static friction μk 100 , μk 300 were recorded at the 100th and 300th reciprocation times. The measuring jig for reciprocating the surface of the test sample used a ball indenter, and a SUS ball (φ3.0 mm) was used for the friction element. The obtained coefficients of static friction μk 100 , μk 300 were applied to the following [Equation 1] to calculate the change amount X of the coefficient of static friction during the reciprocating wear test. [Equation 1] X = (μk 300 - μk 100 ) / μk 100 × 100

[0079] <Exponent Y> As shown in FIG. 2, the peeling prevention layers 3 and the electronic component mounting substrates 12 of each of the examples and comparative examples created by the method described later were cross-sectioned by a polishing method, and the curvature radius R of the curved surface of the corner of the electronic component and the peeling prevention layer covering it was measured with a digital microscope VHX-7000 (manufactured by Keyence Corporation). 1 , R 2 were obtained. Similarly, the thickness (corner thickness of the peeling prevention layer) A 1 of the thinnest part among the corners of the peeling prevention layer was obtained. In the evaluation of these electronic components and the peeling prevention layer, MLCCs with a size of 0.3 mm on the short side and 0.6 mm on the long side (hereinafter also referred to as 0603 MLCC, 0603 MLCC30) were used. The obtained curvature radii R 1 , R 2 , the corner thickness A 1 of the peeling prevention layer were applied to the following [Equation 2] to calculate the exponent Y. [Equation 2] Y = R 2 / (R 1 + A 1 )

[0080] <Thickness A of the peeling prevention layer 2 > The thickness of the peeling prevention layer on the electronic component mounting substrate was defined as the film thickness at the thickest point in the upper surface region of the electronic component observed with a digital microscope VHX-7000 (manufactured by Keyence Corporation) by cross-sectioning using a polishing method. Five samples of cross-sections of different electronic component mounting substrates were measured in the same manner, and the average value was taken as the thickness A 2 .

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

[0082] <Maximum principal stress T of the peeling prevention layer> The release film-attached anti-peeling sheets of each example and comparative example were heated at 180°C for 2 hours, and then cut into pieces with a width of 20 mm and a length of 60 mm. Subsequently, a measurement sample (anti-peeling layer) composed of the anti-peeling sheet was obtained by peeling off the release film. Each measurement sample (anti-peeling layer) was put into an atmosphere of 100°C from room temperature (in the air, 50% RH). One minute later, under the conditions of a tensile speed of 50 mm / min and a relative humidity of 50% at that temperature, a tensile test was carried out using a small bench-top testing machine EZ-TEST (manufactured by Shimadzu Corporation) with an effective tensile size of 20×23 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 measurement samples (anti-peeling layers) of each example and comparative example were measured for Tg using a dynamic viscoelasticity measuring device DVA-200 (manufactured by IT Measurement and Control Co., Ltd.) in accordance with JIS K7198. As the measurement sample, the anti-peeling layer of each example was cut into 0.5 cm×3 cm and the release film was peeled off. The deformation mode was tension, and the temperature at which the main dispersion peak of the loss tangent (tanδ) measured at a strain of 0.08%, a frequency of 10 Hz, and a heating rate of 10°C / min appeared was defined as Tg. However, for the measurement results in cases where the anti-peeling layer was brittle and broke during the measurement, Tg could not be calculated, so it was indicated as "not measurable" in the example table.

[0084] 《Fabrication of anti-peeling sheet》 [Example 1] 100 parts of a thermosetting resin r1 (solid content), 2.0 parts of a curing agent c1, 30 parts of a curing agent c2, 2.9 parts of a filler f1, and 159 parts of a filler f4 were charged into a container, and a mixed solvent of toluene:isopropyl alcohol (mass ratio 2:1) was added so that the non-volatile content concentration became 45% by mass, and the mixture was stirred with a disper for 10 minutes to obtain a composition. This composition was coated on a release sheet using a doctor blade so that the dry thickness became 80 μm. Then, it was dried at 100°C for 2 minutes to obtain the anti-peeling sheet 6 of Example 1.

[0085] [Examples 2 to 21, Comparative Examples 1 to 4] Except for changing the types and blending amounts of the materials in Tables 1 to 2, laminated sheets according to Examples 2 to 21 and Comparative Examples 1 to 4 were obtained by the same procedures. The evaluation results described later for each laminated sheet are also described together.

[0086] [Fabrication of Electronic Component Mounting Substrate 1] (Fabrication of Mounting Substrate) On a substrate made of glass epoxy, a substrate (mounting substrate) was prepared on which 5 × 1 molded and encapsulated electronic components (1 cm × 1 cm) and 8 × 2 arrays of 0603 MLCCs (length 0.6 mm, width 0.3 mm) were mounted. The thickness of the substrate was 0.6 mm, and the mold encapsulation thickness, that is, the height from the upper surface of the substrate to the top surface of the mold encapsulant (component height) H was 0.7 mm. The mounting pitch of the 0603 MLCCs was 200 μm.

[0087] The laminated sheets of each example and comparative example were thermocompression bonded to the above mounting substrate at 2 MPa and 180 °C for 5 minutes, and the cushioning material was peeled off by hand. Then, heating was performed at 180 °C for 2 hours to obtain electronic component mounting substrates of each example and comparative example based on Table 1.

[0088] ≪Evaluation≫ [Wear Resistance] Regarding the anti-peeling layers of each example and comparative example, the anti-peeling layer on the molded and encapsulated electronic components of the above mounting substrate was measured as the test area. Using a continuous load type surface property measuring machine HEIDON Tribogear TYPE: 22H (manufactured by Shinto Kagaku Co., Ltd.), a sufficiently dried test sample was attached on the test bench, a load of 100 g was applied to the friction element, and after the number of reciprocations according to the following evaluation criteria, the surface state of the test sample was observed to confirm whether the exposure of the base material and the breakage of the anti-peeling layer had occurred (reciprocating wear test). When these evaluations were difficult to visually observe, the surface state was observed at 20 times magnification using a digital microscope VHX-7000 (manufactured by Keyence Corporation). In addition, a ball indenter was used as the measuring jig for reciprocating the surface of the test sample, and a SUS ball (φ3.0 mm) was used for the friction element. Also, the wear resistance was evaluated based on the following criteria from these results. +++: After 500 reciprocations, the electronic components under the peeling prevention layer are not exposed. (Extremely good) ++: After 400 reciprocations, the electronic components under the peeling prevention layer are not exposed, and the electronic components under the peeling prevention layer are exposed by 500 reciprocations. (Good) +: After 300 reciprocations, the electronic components under the peeling prevention layer are not exposed, and until 400 reciprocations of peeling prevention the electronic components under the layer are exposed. (Practical level) NG: When the number of reciprocations is less than 300, the electronic components under the peeling prevention layer are exposed. (Defective)

[0089] [Peeling prevention property] As shown in FIG. 5, for the peeling prevention layer 3 at the corner of the 0603 MLCC30 among the electronic components 2 on the electronic component mounting substrate created by the above method, the end of the thickness Ni-SUS plate 14 (formed by forming a nickel layer with a thickness of 2 μm on the surface of a commercially available SUS304 plate with a thickness of 0.2 mm) is applied at 45°, and it is pushed from the side surface side to the top surface side of each corner of the 0603 MLCC30. This is repeated 30 times for each part, and after performing it on the peeling prevention layer 3 on all 16 0603 MLCC30s mounted on the electronic component mounting substrate 12, the number of electronic components 30 peeled off from the electronic component mounting substrate is counted and evaluated as the peeling prevention property (peeling test). Here, for the 0603 MLCC not covered with the peeling prevention layer, when the same test was performed, the components peeled off after about 10 tests. Note that peeling means that, compared with before the test, peeling or separation occurs due to breakage between the electronic component mounting substrate and the electronic component or between the electronic component mounting substrate and the peeling prevention layer, and there is a state where the contact between the electronic component mounting substrate and the electronic component is lost. +++: The number of peeled MLCCs is 0. (Extremely 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. (Defective)

[0090] [Damage resistance] A Ni-SUS plate measuring 30 mm × 80 mm (formed by depositing a 2-μm-thick nickel layer on the surface of a commercially available SUS304 plate with a thickness of 0.2 mm) was prepared. The anti-peeling sheets (25 mm × 70 mm) of each example and comparative example were thermocompression bonded to this plate under the conditions of 2 MPa and 180°C for 5 minutes, and the cushioning material was peeled off by hand. Then, heating was performed at 180°C for 2 hours to obtain a measurement sample (anti-peeling layer). For the measurement sample, in accordance with JIS K7317, a scratching test was conducted using a continuous load type surface property measuring machine HEIDON Tribogear TYPE: 22H (manufactured by Shinto Kagaku Co., Ltd.) to continuously measure the vertical load at which the anti-peeling sheet coated on the substrate peels off at a rate of 50 mm / min. As the scratching needle on the surface of the test sample, a diamond-made one (0.25 mmR) was used, and it was evaluated as scratch resistance according to the following criteria based on the load when the substrate was exposed from the measurement sample. Note that the scratch in scratch resistance refers to the state where the anti-peeling layer is cracked or stretched when the tip of the scratching jig scratches the anti-peeling layer, resulting in peeling and the exposure of the substrate, and it does not refer to the needle mark that is likely to change the observation result by the observer. +++: The vertical load when the substrate is exposed ≧ 350 g (extremely good) ++: 350 g > the vertical load when the substrate is exposed ≧ 250 g. (Good) +: 250 g > the vertical load when the substrate is exposed ≧ 200 g. (Practicable) NG: 200 g > the vertical load when the substrate is exposed. (Poor)

[0091] [Reliability] A mold resin substrate (60 mm × 50 mm) was prepared. The anti-peeling sheets (55 mm × 45 mm) of each example and comparative example were thermocompression bonded to it under the conditions of 2 MPa and 180°C for 5 minutes, and the cushioning material was peeled off by hand. Then, heating was performed at 180°C for 2 hours to obtain a measurement sample (anti-peeling layer). Using a cross-cut guide in accordance with JIS K5600 for this measurement sample, 25 squares with an interval of 1 mm were created on the anti-peeling layer surface on the electronic component. Then, an adhesive tape was pressure-bonded, and the end of the tape was peeled off at a 45° angle in one go to conduct a cross-cut test. As the adhesive tape, a Nichiban-made adhesive tape with a width of 18 mm was used. Among the substrate holes of the peeling prevention layer, the state of the peeling prevention layer remaining on the molded resin substrate (cross-cut remaining rate) was evaluated according to the following criteria. +++: Indicates a cross-cut remaining rate of 100 / 100. (Extremely good) ++: Indicates a cross-cut remaining rate of 95 - 99 / 100. (Good) +: Indicates a cross-cut remaining rate of 80 - 94 / 100. (Practicable) NG: Less than a remaining rate of 80 / 100. (Defective) A sealing sheet was created by the same method as in Example 1, except that the content, thickness Ta, and protective film shown in Tables 2 - 5 were changed, and evaluated in the same way. In addition, all cross-linking agents, oligomers, monomers, polymerization initiators, and other components were added simultaneously.

[0092]

Table 1

[0093]

Table 2

[0094] It was confirmed that the peeling prevention layer with a change rate X of the static friction coefficient less than -50% or exceeding 200% has problems in abrasion resistance and peeling prevention as shown in Comparative Example 1 or 2. It was confirmed that the peeling prevention layer with an index Y less than 0.8 or exceeding 20.0 has problems in peeling prevention as shown in Comparative Example 3 or 4. In contrast, the peeling prevention layer of this example that satisfies all of (1) and (2) of Claim 1 was confirmed to be excellent in abrasion resistance, peeling prevention, scratch resistance, and reliability.

Explanation of Signs

[0095] (Explanation of Figures) 1: Substrate 2: Electronic component 3: Peeling prevention layer 4: Solder bump 5: Hollow part 6: Anti-peeling sheet 7: Cushioning material 8: Functional layer 9: Ground 10: Printed circuit board for mounting electronic components 11: Printed circuit board for mounting electronic components 12: Printed circuit board for mounting electronic components with a functional layer 13: Ni-SUS plate 20: Heating and pressing machine 30: 0603 MLCC 100: Mounting substrate

Claims

1. A substrate; an electronic component mounted on at least one surface of the substrate; An electronic component mounting substrate including the substrate and a peel-off prevention layer that covers the electronic component, The anti-exfoliation layer satisfies both (1) and (2), A peel-preventing sheet which is a precursor of the peel-preventing layer. (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 ) / μk １００ × 100 [Equation 1 (μ １００ : Static friction coefficient of anti-exfoliation layer after 100 reciprocating abrasion tests, μk ３００ (Static friction coefficient after 300 reciprocating abrasion tests of the anti-peeling layer) (2) The index Y calculated by the following formula 2 is 0.8 or more and 20.0 or less. Y=R ２ / (R １ +A １ ) [Formula 2] (R １ ; Radius of curvature of the curved surface of the corner of the electronic component in the cross section of the electronic component mounting board, 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 (thickness of the corner of the peeling prevention layer in the cross section of the electronic component mounting board)

2. The anti-exfoliation layer contains a binder (A) and a filler (B), 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 2. The peel-preventing sheet according to claim 1, wherein the peel-preventing sheet has a viscosity of 1 / g.

3. An anti-peeling sheet as described in claim 1, wherein the maximum point stress T obtained in a tensile test of the anti-peeling layer in accordance with JIS K 7162 is 1 MPa or more and 100 MPa or less.

4. An anti-peeling sheet as described in claim 1, wherein the glass transition temperature Tg of the anti-peeling layer obtained by dynamic viscoelasticity measurement in accordance with JIS K7198 is 5°C or higher and 180°C or lower.

5. A substrate, an electronic component mounted on at least one surface of the substrate; An electronic component mounting substrate including the substrate and a peel-off prevention layer that covers the electronic component, The anti-exfoliation layer satisfies both of (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 ) / μk 100 ×100 [Formula 1] (μk 100 : static friction coefficient of the anti-exfoliation layer after 100 reciprocating abrasion tests, μk 300 : static friction coefficient of the anti-exfoliation layer after 300 reciprocating abrasion tests) (2) The index Y calculated by the following formula 2 is 0.8 or more and 20.0 or less. Y = R2 / (R1+A1) [Formula 2] (R 1 : 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 : radius of curvature of the corner of the peel-preventing layer in the cross section of the electronic component mounting substrate, A 1 : thickness of the corner of the peel-preventing layer in the cross section of the electronic component mounting substrate)

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