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 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, as the miniaturization and thinning of electronic devices progress, the size of the electronic component mounting substrate used is also reduced, and the contact area between the substrate and the electronic components is also decreased. 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 slippage 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 (multilayer 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 cutting costs, there is a demand for forming a thinner protective layer with a reduced thickness after processing.

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 all at once is desired.

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

[0006] Also, even when there is contact or rubbing between a hard member such as metal and an electronic component, a protective member with 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 wear 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]: An electronic component mounting substrate comprising 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). (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 at the corner of the electronic component on the cross-section of the electronic component mounting substrate, R2: Radius of curvature of the corner of the peeling prevention layer on the cross-section of the electronic component mounting substrate, A1: Thickness of the corner of the peeling prevention layer on 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

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. Examples include a work board having a conductive pattern formed on its surface and / or inside, such as a copper foil, a mounting module substrate, a printed wiring board, and a build-up substrate formed by a build-up method.

[0014] Examples of the electronic component 2 include components obtained by molding 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 of their progress in miniaturization.

[0015] When a plurality of electronic components 2 are mounted, their 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 bump 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 bump 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 across 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 press forming method is particularly suitable for the present peeling prevention sheet.

[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 obtained by the following formula 1 is -50% or more and 200% or less. (2) The exponent Y 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 the measurement of X and 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 -μk 100) / 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 at the time of 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 is an index for confirming wear resistance, that is, a state in which a constant coefficient of static friction is maintained when the reciprocating wear test is continued. 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 slipperiness 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 a stable measured value. 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 in 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 a 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 adding a wax component or the like to the anti-peeling layer to improve the slipperiness of the oil replenishing surface, a method of reducing the unevenness of the surface by reducing the amount or changing the shape of the particulate components to be added (reduction of the coefficient of friction of the surface), 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 an anti-peeling sheet serving as a precursor of the anti-peeling layer on the electronic component mounting substrate. Examples of the method for controlling the abrasion resistance of the surface of the anti-peeling layer include, but are not limited to, the exemplified methods. However, 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 from the viewpoint of productivity because there is no need to perform special pre / 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] Note that R in [Formula 2] 2 , R 1 , A 1 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, 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 be either a thermoplastic resin or a thermosetting resin and a curing 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 known resins such as acrylic resins, maleic acid resins, polybutadiene resins, polyester resins, polyurethane resins, polyurethane-urea resins, epoxy resins, oxetane resins, phenoxy resins, polyimide resins, polyamide resins, polyamide-imide resins, phenolic resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, fluororesins, etc. 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 compound 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 crosslink 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 is preferably contained in an amount of 1 to 50 parts by mass, more preferably 15 to 30 parts by mass, per 100 parts by mass of the thermosetting resin. When the amount of the difunctional curable compound is 1 part by mass or more, a strong crosslinked structure is formed in the peeling prevention layer, improving the resistance to thermal damage. Further, when it is 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, when the amount of the curable compound is 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. When the amount is 0.8 parts by mass or more, the adhesion between the peeling prevention layer and the base material is improved, and the reliability can be enhanced. 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 is 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, waxes include 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.

[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 favorable range. When insulation is required, an insulating filler is used; when conductivity is required, a conductive filler is used; and when electromagnetic wave absorption is required, an electromagnetic wave absorbing filler is used. The shape of the filler can be 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 a flake-shaped filler and a dendrite-shaped filler.

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

[0043] Examples of the conductive filler include metal fillers, conductive ceramic fillers, and mixtures thereof. Examples of the metal filler 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, a conductive filler containing silver is preferred. From the viewpoint of cost, silver-coated copper powder is particularly preferred.

[0044] Examples of the electromagnetic wave absorbing filler include iron alloys such as iron, Fe-Ni 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 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 when worn, 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 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, the product of the specific surface area and the content) are 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. In addition, 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 molding 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 all 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, UL-100 (manufactured by ADEKA Corporation). Examples of the polyester include Polysizer TD-1720, Polysizer S-2002, 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 is 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 supplementarily 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 color developer, a flame retardant, a lubricant, an anti-blocking agent, etc. Examples of the colorant include organic pigments, carbon black, ultramarine, safflower, zinc white, titanium oxide, graphite, and dyes. Examples of the UV color developer 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 and 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 principal 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 principal 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 principal stress T is 1 MPa or more, the abrasion resistance and scratch resistance can be improved. On the other hand, when the maximum principal 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 the peeling of the electronic component and the breakage of the peeling prevention layer at the corners due to the occurrence of cracks and cracks in the peeling prevention layer are likely to occur, it is possible to suppress defects in appearance and processing.

[0056] The maximum principal stress T of the peeling prevention layer can be adjusted by the selection of the thermoplastic resin or 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 weight 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. In addition, by setting the Tg to 20°C or more and 80°C or less, it is possible to achieve both resistance to frictional heat due to abrasion and thermal damage in the inspection in the subsequent process, and improve the reliability. 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 above a predetermined level for a predetermined period of time to cause a curing reaction, thereby forming the anti-peeling layer. The anti-peeling sheet may be provided with a release sheet on one 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] 《Method for manufacturing anti-peeling sheet》 The method for manufacturing the anti-peeling sheet is not particularly limited. For example, there is 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. Examples of the coating method include 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.

[0060] The anti-peeling sheet of the present invention may be laminated with two or more anti-peeling sheets in order 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] 《Use 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 may 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 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. FIG. 3 shows an example in which the cushion material 7 is used. 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 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, for example, a material having thermoplasticity, but preferably has a melting temperature and a glass transition point (Tg) lower than the temperature during pressurization. Suitable 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 a plurality of cushion materials 7 are laminated, 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 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 softens or melts due to heat and promotes following the unevenness between the electronic components of 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, a vacuum forming method or a vacuum pressure forming method 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, with the anti-peeling sheet 6 in a deformed state, it is further heated at a temperature of 150°C to 230°C for 10 minutes to 60 minutes, thereby thermosetting the thermosetting resin in the anti-peeling sheet 6 and forming the anti-peeling layer 3. The anti-peeling layer firmly adheres to the electronic component and the substrate, and functions as an anti-peeling layer for preventing and protecting the damage of the electronic component from external impacts and scratches. Incidentally, by setting the temperature of heating and pressing to 150°C or higher and the time to 30 minutes or more at the stage of (Step iv), the thermosetting can be completed to form the anti-peeling layer 3 as well.

[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 layers are, for example, layers 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 Equipment》 The electronic component mounting substrate of the present invention is preferably provided in electronic equipment such as liquid crystal displays, touch panels, as well as notebook PCs, mobile phones, smartphones, tablet terminals, etc.

Examples

[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 size: 24 nm, BET specific surface area: 120 m 2 / g), manufactured by Mitsubishi Chemical Corporation Filler f2: Silica "Ultrasil U360" (average primary particle size: 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 static friction coefficient during reciprocating wear test> Regarding the anti-peeling layers of each example and comparative example, below the anti-peeling layer, among the resin-containing regions, a smooth portion of 6 mm × 6 mm or more on a chip (electronic component) made of mold resin (sealing resin) or an electronic component mounting substrate 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 onto the test bench, a load of 100 g was applied to the friction element, and the static friction coefficients μk 100 , μk 300 at the 100th and 300th reciprocation times were recorded. Note that a ball indenter was used as the measuring jig when reciprocating on the test sample surface, and a SUS ball (φ3.0 mm) was used for the friction element. The obtained static friction coefficients μk 100 , μk 300 were applied to the following [Equation 1] to calculate the change amount X of the static friction coefficient 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 layer 3 and the electronic component mounting substrate 12 of each example and comparative example 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 of the thinnest part among the corners of the peeling prevention layer was obtained. 1 In the evaluation of these electronic components and the peeling prevention layer, those with a size of 0.3 mm on the short side and 0.6 mm on the long side among MLCCs (hereinafter also referred to as 0603 MLCC, 0603 MLCC30) were used. The obtained curvature radii R 1 , R 2 , the corner thickness A of the peeling prevention layer 1 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 by a polishing method. Five samples of cross-sectioning of different electronic component mounting substrates were measured in the same way, 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 a size of 20 mm in width × 60 mm in length. Next, by peeling the release film, a measurement sample (anti-peeling layer) made of the anti-peeling sheet was obtained. 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, using a small desktop testing machine EZ-TEST (manufactured by Shimadzu Corporation), a tensile test was carried out 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 one with the release film peeled off was used. 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, since the anti-peeling layer was brittle and broke during the measurement, the Tg could not be calculated for the measurement results in such cases, so "measurement impossible" was indicated in the example table.

[0084] 《Fabrication of anti-peeling sheet》 [Example 1] 100 parts of thermosetting resin r1 (solid content), 2.0 parts of curing agent c1, 30 parts of curing agent c2, 2.9 parts of filler f1, and 159 parts of filler f4 were charged into a container, and a mixed solvent of toluene:isopropyl alcohol (mass ratio 2:1) was added 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, by drying at 100 °C for 2 minutes, the anti-peeling sheet 6 of Example 1 was obtained.

[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 (component height) H from the upper surface of the substrate to the top surface of the mold encapsulation material 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. Thereafter, heating was performed at 180 °C for 2 hours, and electronic component mounting substrates of each example and comparative example were obtained 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 component among the above mounting substrates 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 exposure of the base material and breakage of the anti-peeling layer had occurred (reciprocating wear test). When these evaluations were difficult to perform visually, 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. Further, 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 the electronic components under the peeling prevention layer are exposed by 400 reciprocations. (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, with respect to 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 parts peeled off after about 10 tests. Note that peeling means a state where 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 compared to before the test, and there is a part 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 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 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 terms of 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 is not 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 this 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 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 eyes of the peeling prevention layer, the state (cross-cut remaining rate) of the peeling prevention layer remaining on the molded resin substrate 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 of 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 of 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 described above was confirmed to be excellent also 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 with electronic components 11: Printed circuit board with electronic components 12: Printed circuit board with electronic components having a functional layer 13: Ni-SUS plate 20: Heating and pressing machine 30: 0603 MLCC 100: Mounting board

Claims

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), an electronic component mounting substrate. (1) The change rate X of the coefficient of static friction, determined by the following [Formula 1], is -50% or more and 200% or less. X = (μk ３００ - μk １００ ) / μk １００ × 100 [Equation 1] (μk １００ ; Coefficient of static friction μk at the 100th reciprocating wear test of the anti-peeling layer ３００ ; Coefficient of static friction at the 300th reciprocating wear test of the anti-peeling layer) (2) The exponent Y determined by the following [Formula 2] is 0.8 or more and 20.0 or less. Y = R ２ / (R １ + A １ ) [Equation 2] (R １ ; The radius of curvature, R, of the curved surface of the corner of the electronic component in the cross-section of the electronic component mounting substrate ２ ; The radius of curvature, A, of the corner of the peeling prevention layer in the cross-section of the electronic component mounting substrate １ ; The corner thickness 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 [m ２ / 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 · m ２ / g]. The electronic component mounting substrate according to claim 1.

3. The thickness A of the peeling prevention layer ２ The electronic component mounting substrate according to claim 1, wherein the thickness A is 5 to 300 μm.

4. An electronic device on which the electronic component mounting substrate according to any one of Claims 1 to 3 is mounted.

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