Electronic component mounting substrate, electronic component protection sheet, and electronic device

Abstract

The present application provides an electronic component mounting substrate having excellent insulating properties, excellent cold and hot cycle resistance, and excellent cutting suitability, an electronic component protection sheet, and an electronic device. In an electronic component mounting substrate (10), an electronic component (2) is mounted on a substrate (1), and the electronic component (2) is covered with an electronic component protection layer (3). In the surface of the electronic component protection layer (3), a dynamic index (FI) calculated using equation (1) is set to 0.3 to 80.(L * 15° , L * 45° , L * 110° are L * a * b * of a surface color system specified by JIS Z8781-4 at an offset angle of 15°, 45°, and 110° from the normal direction of light incident at an angle of 45° with respect to the surface of the electronic component. * .[Equation 1]

Description

[0001] This application claims priority to Japanese Patent Application No. 2021-124665, Japanese Patent Application No. 2021-124666, and Japanese Patent Application No. 2021-124667, filed on July 29, 2021, the disclosures of which are incorporated herein in their entireties. TECHNICAL FIELD

[0002] The present disclosure relates to an electronic component mounting substrate, an electronic component protection sheet, and an electronic device. BACKGROUND

[0003] In order to protect electronic components such as integrated circuit (IC) chips mounted on a substrate from the effects of bending or impact on the substrate, or to protect them from the effects of thermal shock caused by temperature changes, a portion or the entire surface of the substrate is coated with a resin for the electronic components. In recent years, as the performance of electronic components and substrate circuits to be protected has improved significantly or has been miniaturized, the level of protection required of the material used for the coating has been increasing.

[0004] As a method for coating electronic components, a solvent-free electronic component protection sheet having thermal meltability formed into a sheet has been proposed as a substitute for a conformal coating that has been performed since before.

[0005] For example, Patent Document 1 discloses a moisture-proof sheet for electronic device components, characterized by including a moisture-proof layer containing a forming material in which an aromatic vinyl-conjugated diene block copolymer is the main component.

[0006] Patent Document 2 discloses a sheet for protecting a substrate, which contains a graft copolymer of an olefin-based monomer, an ethylenically unsaturated carboxylic acid, and an aromatic ethylenically unsaturated monomer.

[0007] Patent Documents 3 and 4 disclose a sheet-shaped resin composition containing an epoxy resin, an inorganic filler, and a flame retardant.

[0008] Patent Document 5 discloses a method for manufacturing a mounting structure that covers a mounting component and a substrate using a laminated sheet including a first thermal conductive layer and a second thermal conductive layer, and Figure 3 (b) discloses a method for manufacturing a mounting structure that fills a gap between a mounting component and a mounting component without gaps using a hardened product of the laminated sheet.

[0009] Patent Document 6 discloses a flexible printed wiring board including an electrically insulating layer having an average surface roughness within a specific range, and a conductor layer.

[0010] Patent Document 7 discloses a structure in which a thermoplastic elastomer is coated on the surface of a flexible circuit body having an insulating film, a wiring layer formed on the insulating film, and an insulating layer formed on the wiring layer.

[0011] Patent Document 8 discloses an electronic component mounting substrate having an electromagnetic wave shielding layer containing a conductive filler and a binder resin, and covering an electronic component with an electromagnetic wave shielding member having a kurtosis in a specific range.

[0012] Prior Art Documents

[0013] Patent Documents

[0014] Patent Document 1: Japanese Patent Laid-Open No. 2003-145687

[0015] Patent Document 2: Japanese Patent Laid-Open No. 2010-06954

[0016] Patent Document 3: Japanese Patent Laid-Open No. 2011-246596

[0017] Patent Document 4: Japanese Patent Laid-Open No. 2012-054363

[0018] Patent Document 5: Japanese Patent Laid-Open No. 2019-021757

[0019] Patent Document 6: Japanese Patent Laid-Open No. 2008-160151

[0020] Patent Document 7: International Publication No. 2012 / 147412

[0021] Patent Document 8: International Publication No. 2020 / 129985 SUMMARY

[0022] PROBLEMS TO BE SOLVED BY THE INVENTION

[0023] As described above, inventions related to electronic component mounting substrates coated and protected by various methods have been disclosed so far, but in recent years, electronic component mounting substrates that are required to have a high level of performance and are more excellent in quality are desired.

[0024] An electronic component protection layer laminated on an electronic component mounting substrate is required to have high insulation in order to achieve the effect of insulatingly coating an underlying electronic component or substrate.

[0025] In addition, in order to improve the productivity of the electronic component mounting substrate, sometimes electronic components are mounted on a large substrate, for example, in an array shape, and a cutting process is performed in which the substrate is cut in sections for each specific component. In this case, cutting adaptability is required in the electronic component protection layer. An electronic component protection layer that does not have cutting adaptability can cause the cut surface of the electronic component protection layer to collapse or generate burrs due to stress caused by cutting. Furthermore, the burrs referred to in this specification mean curling of the electronic component protection layer based on the cut surface of the electronic component protection layer.

[0026] Furthermore, after the electronic component mounting substrate is assembled into an electronic machine, it is used in various temperature environments, and thus the electronic component protection layer is exposed to drastic temperature changes, and the electronic component protection layer itself can sometimes be damaged. Therefore, there is a strong demand for an electronic component protection layer that has excellent cold and heat cycle resistance.

[0027] The electronic component mounting substrate is not allowed to have dust or dirt attached thereto because it is assembled into an electronic machine. For example, an article having dust that cannot be removed, which is embedded in the unevenness of the electronic component protection layer, is judged to be unusable in the inspection process, and sometimes it is discarded. Therefore, there is a demand for an electronic component protection layer that has excellent stain resistance. Furthermore, in the case where quality inspection of the electronic component protection layer (whether or not the corners are cracked or the end portions are excessively flowed, etc.) is performed, if the electronic component protection layer itself is not colored, it cannot be visually recognized and defects, etc. can be missed, thereby causing a problem in inspection accuracy. On the other hand, if it is simply colored black, etc., it is difficult to recognize defects on a chip that is sealed by a black sealing resin in the electronic component, and it also causes a problem in inspection accuracy.

[0028] The present disclosure was made in view of the problems described above, and a first object thereof is to provide an electronic component mounting substrate that has excellent insulating properties, excellent cold and heat cycle resistance, and excellent cutting adaptability, and an electronic component protection sheet. In addition, a second object thereof is to provide a high-quality electronic component protection sheet that has high stain resistance and excellent recognition, and an electronic component mounting substrate including the electronic component protection sheet.

[0029] Technical means for solving the problem

[0030] The present inventors made diligent studies, and as a result, found that the problems described above can be solved by using an article (electronic component mounting substrate and electronic component protection sheet) having the following characteristics, thereby completing the present disclosure.

[0031] [1] An electronic component mounting substrate on which an electronic component is mounted, and the electronic component is covered with an electronic component protection layer, in which a dynamic index (Flop Index, FI) calculated from a surface of the electronic component protection layer using Formula (1) is 0.3 to 80.

[0032] [Formula 1]

[0033]

[0034] (L * 15° , L * 45° , L * 110° are L * a * b * of L * )

[0035] [2] An electronic component mounting substrate on which an electronic component is mounted, and the electronic component is covered with an electronic component protective layer, in the electronic component mounting substrate, in a surface of the electronic component protective layer,

[0036] a root mean square slope Sdq according to International Organization for Standardization (ISO) 25178-2:2012 is 0.0001 to 5.0.

[0037] [3] The electronic component mounting substrate according to [2], characterized in that,

[0038] in a surface of the electronic component protective layer,

[0039] a root mean square height Sq according to ISO 25178-2:2012 is 0.01 pm to 10 pm, and satisfies the following formulas (2) and (3).

[0040] y ≦ 195x - 0.553 (2)

[0041] y ≧ 0.258x (3)

[0042] (x: a root mean square slope Sdq of a surface of the electronic component protective layer according to ISO 25178-2:2012, y: a root mean square height Sq of a surface of the electronic component protective layer according to ISO 25178-2:2012)

[0043] [4] The electronic component mounting substrate according to any one of [1] to [3], characterized in that the optical density (OD value) of the electronic component protection layer in a visible light region of 360 nm to 760 nm defined by ISO 5-2 is 1 to 6.

[0044] [5] The electronic component mounting substrate according to any one of [1] to [4], characterized in that the L * a * b * value of the electronic component protection layer in a color system is 1 to 50, and the a * value is -10 to 10, and the b * value is -10 to 10. *

[0045] [6] The electronic component mounting substrate according to any one of [1] to [5], characterized in that the surface resistance value of the electronic component protection layer is 1.0 x 10 7 Ω / γ or more.

[0046] [7] The electronic component mounting substrate according to any one of [1] to [6], characterized in that the electronic component protection layer contains a binder resin and a particulate modifier,

[0047] the dibutyl phthalate (DBP) oil absorption amount of the particulate modifier defined by JIS K 6217-4 is 15 ml / 100 g to 400 ml / 100 g.

[0048] [8] The electronic component mounting substrate according to [7], characterized in that the particulate modifier contains at least one kind of carbon black.

[0049] [9] An electronic machine mounting the electronic component mounting substrate according to any one of [1] to [8].

[0050]

[10] An electronic component protection sheet for covering an electronic component mounted on a substrate, the electronic component protection sheet comprising,

[0051] a dynamic index (FI) calculated using formula (1) of a surface of a hardened film of the electronic component protection sheet heated at 180°C for 60 minutes is 0.3 to 80.

[0052] [Formula 1]

[0053]

[0054] (L * ​15° , L * 45° , L * 110° L * a * b * L * )

[0055]

[11] An electronic component protection sheet for covering an electronic component mounted on a substrate, wherein

[0056] The root mean square slope Sdq of the surface of the hardened film of the electronic component protection sheet obtained in accordance with ISO 25178-2:2012 is 0.0001 to 5.0 when the electronic component protection sheet is heated at 180°C for 60 minutes.

[0057]

[12] The electronic component protection sheet according to

[11] for covering and protecting one electronic component or a group of electronic components including a plurality of electronic components mounted on a substrate, characterized in that

[0058] The surface of the hardened film of the electronic component protection sheet obtained in accordance with ISO 25178-2:2012 is 0.01 μm to 10 μm, and satisfies the following mathematical expression (2) and mathematical expression (3).

[0059] Sq is 0.01 μm to 10 μm, and satisfies the following mathematical expression (2) and mathematical expression (3).

[0060] y ≦ 195x - 0.553 (2)

[0061] y ≧ 0.258x (3)

[0062] (x: root mean square slope Sdq of the surface of the electronic component protection layer obtained in accordance with ISO 25178-2:2012, y: root mean square height Sq of the surface of the electronic component protection layer obtained in accordance with ISO 25178-2:2012)

[0063] Effects of the Invention

[0064] By the invention of the first aspect of the present disclosure, the excellent effects of providing an electronic component mounting substrate having excellent insulating properties, excellent cold-heat cycle resistance, and excellent cutting adaptability, and an electronic component protection sheet are achieved.

[0065] By the second aspect of the present disclosure, an electronic component protection sheet having high quality with high stain resistance and excellent recognition, and an electronic component mounting substrate including the same can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0066] Figure 1 is a schematic cross-sectional view of an electronic component mounting substrate of the present embodiment.

[0067] Figure 2A is a diagram illustrating a dynamic index (FI) measurement system.

[0068] Figure 2B is a diagram illustrating an FI measurement system.

[0069] Figure 2C is a diagram illustrating an FI measurement system.

[0070] Figure 3 is a diagram showing an example of an aggregate of the particulate modifier of the present embodiment.

[0071] Figure 4 is a schematic view showing a manufacturing process of the electronic component mounting substrate of the present embodiment.

[0072] Figure 5 is a schematic cross-sectional view of an electronic component mounting substrate having a conductive layer of the present embodiment.

[0073] Figure 6 is a schematic cross-sectional view of a test substrate of the present embodiment.

[0074] Figure 7A is a schematic plan view for illustrating a substrate for a water vapor transpiration test.

[0075] Figure 7B is a schematic plan view for illustrating a substrate for a water vapor transpiration test.

[0076] Figure 7C is a VIIC-VIIC cut portion cross-sectional view of Figure 7B

[0077] Explanation of Symbols

[0078] 1: Substrate

[0079] 2, 2a, 2b: Electronic component

[0080] 3: Electronic component protection layer

[0081] 4: Solder bump

[0082] 5: Hollow portion

[0083] ​6: Protective film for electronic components

[0084] 7: Cushioning material

[0085] 8: Conductive layer

[0086] 9: Grounding

[0087] 10: Electronic components mounting substrate

[0088] 11: Electronic component mounting substrate with conductive layer

[0089] 12: Incident light

[0090] 13: Measuring the surface of the object

[0091] 20: Heating and Pressurizing Machine

[0092] 21: Primary particle

[0093] 22: Aggregate

[0094] 23: Space

[0095] 31: Polyimide film

[0096] 32: Comb-type signal wiring for cathode electrodes

[0097] 32': Cathode electrode connection point

[0098] 33: Comb-type signal wiring for anode electrodes

[0099] 33': Anode electrode connection point

[0100] 100: Mounting substrate / electronic component mounting substrate Detailed Implementation

[0101] [First Implementation Method]

[0102] Electronic component mounting substrate

[0103] like Figure 1 As shown, the electronic component mounting substrate 10 of the first embodiment includes: a substrate 1; one or more electronic components 2 mounted on the substrate; and an electronic component protective layer 3 that covers and protects part or all of the electronic components 2 and the substrate 1. The electronic component protective layer 3 covers the substrate 1 from the upper surface of the electronic component 2, and covers not only the upper surface of the electronic component 2, but also the side surfaces of the stepped portions formed by mounting the electronic component 2 and at least a portion of the substrate. Furthermore, the electronic component protective layer 3 is not limited to a structure that covers the electronic component 2 in a manner that follows its shape, and also includes a form in which the electronic component 2 and the substrate 1 are covered on the electronic component 2.

[0104] The electronic component 2 can be electrically connected to the substrate via the solder bumps 4, and a connection terminal extending from the electronic component can also be directly connected to the substrate. In the case where the electronic component 2 is connected to the substrate via the solder bumps 4, as shown in FIG. 3, a hollow portion 5 is created between the electronic component 2 and the substrate 1. The electronic component protective layer 3 can coat and protect the electronic component 2 and the substrate 1 in such a way as to maintain the hollow portion 5, or can coat and protect the electronic component 2 and the substrate 1 in such a way as to fill the hollow portion 5. The electronic component protective layer can be manufactured by, for example, the method described later. Figure 1

[0105] Electronic Component Protective Layer

[0106] Next, the electronic component protective layer of the first embodiment will be described. As described above, the electronic component protective layer is used to coat and protect an electronic component mounted on a substrate.

[0107] Root Mean Square Height Sq

[0108] The root mean square height Sq (hereinafter, also referred to as Sq) is a surface property parameter defined by the following equation (4) in ISO 25178-2:2012. A represents the area of the defined surface.

[0109] [Equation 4]

[0110]

[0111] The root mean square height Sq can be calculated by processing coordinate data of the surface shape obtained using any one of an optical microscope, a laser microscope, and an electron microscope, by an analysis software. The root mean square height Sq represents the root mean square of the concave-convex height on the defined surface, and represents the standard deviation of the surface roughness.

[0112] The surface of the electronic component protective layer in the first embodiment is preferably a root mean square height Sq of 0.15 μm to 1.0 μm, as calculated in accordance with ISO 25178-2:2012. By having the surface of the electronic component protective layer in this range, when an electrified object comes into contact with the surface of the electronic component protective layer, a moderate gap can be maintained at the interface, and thus the insulation property can be improved, and the insulation breakdown voltage can be increased. In addition, by having the surface of the electronic component protective layer in this range, a moderate stress concentration can be created at the cutting point with a tool in the cutting process, and thus the generation of burrs can be more effectively suppressed.

[0113] Root Mean Square Slope Sdq

[0114] The root mean square slope Sdq (hereinafter, also referred to as Sdq) is a surface property parameter defined by the following equation (5) in ISO 25178-2:2012. A represents the area of the defined surface, ​This represents a small displacement along the x-axis. This represents a small displacement along the y-axis. It represents a small displacement in the z-axis direction.

[0115] [Formula 5]

[0116]

[0117] The root mean square slope Sdq can be calculated by processing the coordinate data of the surface shape obtained using any of the optical, laser, or electron microscopes through analysis software. The root mean square slope Sdq represents the root mean square of the slope at all points defining the surface, and is a parameter representing the steepness of the surface's unevenness.

[0118] In the first embodiment, the surface of the electronic component protective layer preferably has a root mean square slope Sdq of 0.0001 to 5, as determined according to ISO 25178-2:2012. By having the surface of the electronic component protective layer within this range, the anti-fouling properties of the electronic component protective layer can be improved. By setting the root mean square slope Sdq to 0.0001 or higher, a suitable uneven slope can be imparted to the electronic component protective layer, and the adhesion of dust or dirt can be suppressed. On the other hand, by setting the root mean square slope Sdq to 5 or lower, the adhesion of fine dust or dirt to the uneven surface of the electronic component protective layer can be suppressed. More preferably, the root mean square slope Sdq of the electronic component protective layer is 0.0005 to 4.5, more preferably 0.001 to 4, and particularly preferably 0.005 to 3.5.

[0119] Dynamic Index (FI)

[0120] The dynamic index (FI) (hereinafter also referred to as FI) is a parameter calculated by formula (1).

[0121] [Formula 1]

[0122]

[0123] The FI measurement system is shown in Figure 2A FI uses brightness L. * To calculate the brightness L * It is obtained by irradiating light (incident light 12) at an incident angle of 45° relative to the perpendicular direction of the surface 13 of the object being measured, detecting the light reflected at a certain angle (normal reflected light) using a detector, and then quantifying the result. L * L as specified by JIS Z8781-4 * a * b * Lightness (L) in the color system * L *15° , L * 45° , L * 110° L45, L45, and L110 are L values observed at an offset angle of 15°, 45°, and 110°, respectively, from the regular reflection light of the light incident at an angle of 45° with respect to the perpendicular direction of the surface of the measurement target. * .

[0124] FI becomes an index of the steepness of the concave-convex shape of the surface of the measurement target and the orderliness of the surface concave-convex shape. As shown in FIG. 6, in a case where the concave-convex shape of the surface of the measurement target is steep and has no orderliness, the incident light 12 is reflected (scattered) at all angles, and thus the angle dependence of the amount of light detected becomes small. As a result, the value of FI calculated using equation (1) becomes a small value. On the other hand, as shown in FIG. 7, in a case where the concave-convex shape of the surface of the measurement target is gentle and has high orderliness, the incident light 12 is strongly reflected at certain angles, and thus the angle dependence of the amount of light detected becomes large. In particular, among the light observed at the offset angles of 15°, 45°, and 110°, the amount of light at 15° becomes large, and thus FI becomes a large value. Figure 2B Figure 2C

[0125] (Effect of FI)

[0126] FI of the surface of the electronic component protective layer in the first embodiment is 0.3 to 80. By having FI in the range, the cutting adaptability and the voltage resistance (insulation breakdown voltage) of the electronic component protective layer are good. By having FI of 0.3 or more, a certain orderliness can be imparted to the concave-convex shape of the surface of the electronic component protective layer. By imparting a certain orderliness to the surface concave-convex shape when a voltage is applied to the electronic component protective layer, the starting point of insulation breakdown can be suppressed, and thus the voltage resistance (insulation breakdown voltage) is improved. On the other hand, by having FI of the surface of the electronic component protective layer of 80 or less, a certain disorderliness can be imparted to the surface concave-convex shape. In a surface where the concave-convex shape has high orderliness, external stress applied due to cutting or the like tends to concentrate on a certain portion, but in a case where the concave-convex shape has a certain disorderliness, the external stress can be appropriately dispersed, and thus the cutting adaptability is improved. In addition, the cold-heat cycle resistance can be improved. FI of the surface of the electronic component protective layer is more preferably 1 to 75, further preferably 3 to 50, and particularly preferably 5 to 26.

[0127] ​​Furthermore, the inventors conducted extensive research and discovered that by setting the FI (fiber optic index) of the electronic component protective layer surface to 5-26, the resistance to thermal cycling was further improved. After being assembled into electronic devices, electronic component mounting substrates are used in various temperature environments, and therefore the electronic component protective layer is sometimes exposed to rapid temperature changes. When the FI of the electronic component protective layer surface is within a specific range, and the surface unevenness has a certain degree of randomness, the stress caused by the expansion / contraction of the electronic component protective layer relative to rapid temperature changes can be appropriately dispersed, thus preventing damage to the electronic component protective layer during temperature changes.

[0128] [Control methods for Sq, Sdq, and FI]

[0129] Methods for controlling the root mean square height Sq, root mean square slope Sdq, and dynamic index (FI) of the surface of the electronic component protective layer can utilize existing known methods for adjusting the surface shape of an object, or they can employ different methods or common methods. Specifically, examples include: grinding the surface using abrasive paper; shot blasting by blowing abrasive material onto the surface of the electronic component protective layer using compressed air; and forming an electronic component protective sheet 6 (see reference) as a precursor to the electronic component protective layer on a carrier material having a specified root mean square height Sq, root mean square slope Sdq, or FI. Figure 4 Methods include: transferring the unevenness of the carrier material surface; pressing a film having a specified root mean square height Sq, root mean square slope Sdq, or FI to an electronic component protective sheet 6 and transferring the unevenness of the film surface; and containing particulate matter in the electronic component protective layer to control surface unevenness. The methods for controlling Sq, Sdq, and FI on the surface of the electronic component protective layer are not limited to the illustrated methods, but any method that contains particulate matter in the electronic component protective layer to control surface unevenness does not require special pre-treatment / post-treatment, and is therefore preferred from a production point of view.

[0130] Optical density (OD value)

[0131] Optical density (hereinafter also referred to as OD value) is the attenuation rate of incident light passing through an object, and is a parameter calculated using equation (6). PI represents the amount of incident light at a specific wavelength, and PT represents the amount of transmitted light at a specific wavelength.

[0132] [Formula 6]

[0133] OD(λ) = log 10 (PI(λ) / PT(λ)) (6)

[0134] The higher the optical density (OD value), the greater the attenuation rate of the incident light; therefore, it can be said that the object has good light-blocking properties. For example... Figure 1 As shown, in the structure where an electronic component protective layer 3 is stacked on top of an electronic component 2, the higher the optical density (OD value) of the electronic component protective layer 3, the higher its light-blocking ability. Light will not shine on or be reflected onto the underlying electronic component 2, making it difficult for the observer to perceive the color of the electronic component. Therefore, when the colors of the electronic component and the electronic component protective layer differ, the portion with the electronic component protective layer and the portion without it can be determined by appearance. From this perspective, the optical density (OD value) of the electronic component protective layer in the 360nm to 760nm (visible light region) range as specified in ISO 5-2 is preferably in the range of 0.5 to 6, more preferably 1 to 6, and even more preferably in the range of 2 to 6.

[0135] In the protection layer of electronic components, there is a need for techniques to improve the quality inspection accuracy of items such as cracks at the edges of electronic components and excessive flow (exudation) at the ends of the protective layer. While there are methods to color the protective layer of electronic components black, simply coloring it black makes it difficult to identify, for example, on a chip sealed with black sealing resin. Therefore, techniques are sought to improve inspection accuracy. According to the electronic component protective layer of the first embodiment, by setting the OD value to the aforementioned range, the electronic component protective layer itself can be appropriately colored, improving visibility and thus effectively improving inspection accuracy.

[0136] Examples of methods for increasing the OD value of a protective layer for electronic components include using an adhesive resin exhibiting high light absorption properties and methods containing fillers that scatter incident light. The scattering effect of incident light can also be obtained with granular modifiers described later; by controlling the type and / or amount of the granular modifier, the OD value of the protective layer for electronic components can be set to a desired range.

[0137] L * a * b * value"

[0138] In the first embodiment, the electronic component protective layer is preferably L as specified in JIS Z8781-4. * a * b * L in the color system * The value is 1 to 50, and a * The value is between -10 and 10, and b * The value ranges from -10 to 10. By using L... * a * b * When the value is set to the specified range, the color difference from the substrate becomes more pronounced, improving recognizability. Furthermore, L...* a * b * Values are coordinate axes of a color space. L * is a lightness dimension, a * and b * represent complementary color dimensions. L * The lower the value, the a * b * value closer to 0, the higher the jet blackness of the object surface, and the more distinct the color difference from the normally colored substrate. Here, L * is L * 45° . L * The value is more preferably 1 to 40, and further preferably 1 to 30. In addition, the a * value and the b * value are more preferably -5 to 5, and further preferably -3 to 3.

[0139] The electronic component protective layer of the first embodiment is optimized in terms of Sdq, OD value, and L * a * b * values, and even when the electronic component protective layer is formed on an electronic component and a substrate of any color, the electronic component protective layer is visually recognized, and the inspection accuracy can be significantly improved.

[0140] "Insulating property of the electronic component protective layer"

[0141] In terms of the necessity of covering and protecting a power conducting material such as an electronic component or a circuit mounted on an electronic component mounting substrate, the electronic component protective layer is preferably excellent in insulating property. Specifically, the surface resistance value of the electronic component protective layer is preferably 1.0 x 10 7 Ω / Υ or more, more preferably 1.0 x 10 8 Ω / r or more, and further preferably 1.0 x 10 9 Ω / r or more.

[0142] "Adhesive resin"

[0143] The electronic component protective layer contains an adhesive resin. The adhesive resin becomes the matrix of the electronic component protective layer. The particulate modifier described later or any other component is contained. The adhesive resin can use any one or a combination of a thermoplastic resin or a thermosetting resin and a hardening agent.

[0144] [Thermoplastic resin]

[0145] As the thermoplastic resin, there can be mentioned: polyolefin-based resins, vinyl-based resins, styrene-acrylic acid-based resins, diene-based resins, terpene resins, petroleum resins, cellulose-based resins, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, fluorine resins, and the like. Although there is no particular limitation, from the viewpoint of heat resistance, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, and fluorine resins are more preferable. The thermoplastic resin can be used alone or in combination of two or more kinds.

[0146] [Thermosetting resin]

[0147] The thermosetting resin is a resin having a plurality of functional groups capable of reacting with a hardening agent. The functional group can be mentioned, for example: a hydroxyl group, a phenolic hydroxyl group, an 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 mercaptan group, an isocyanate group, a blocked isocyanate group, a blocked carboxyl group, a silanol group, and the like. The thermosetting resin can be mentioned, for example: known resins such as acrylic resins, maleic acid resins, polybutadiene-based resins, polyester resins, polyurethane resins, polyurethane urea resins, epoxy resins, oxetane resins, phenoxy resins, polyimide resins, polyamide resins, polyamide-imide resins, phenol-based resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, fluorine resins, and the like. The thermosetting resin can be used alone or in combination of two or more kinds.

[0148] Of these, from the aspect of heat resistance, polyurethane resins, polyurethane urea resins, polyester resins, epoxy resins, phenoxy resins, polyimide resins, polyamide resins, polyamide-imide resins are preferable.

[0149] [Hardening agent]

[0150] The hardening agent has a plurality of functional groups capable of reacting with the functional groups of the thermosetting resin. The hardening agent can be mentioned, for example: known compounds such as epoxy compounds, anhydride group-containing compounds, isocyanate compounds, aziridine compounds, amine compounds, phenol compounds, organometallic compounds, and the like. The hardening agent can be used alone or in combination of two or more kinds.

[0151] The hardening agent is preferably contained at 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the thermosetting resin. By the amount of the hardening agent being 1 part by mass or more, a firm crosslinked structure is formed in the electronic part protective layer, and the voltage resistance (insulation breakdown voltage) is improved. On the other hand, by the amount of the hardening agent being 50 parts by mass or less, excessive hardening of the electronic part protective layer can be suppressed, and in the manufacturing process of the electronic part mounting substrate described later, the electronic part protective sheet 6 (refer to FIG. 1) is less likely to be damaged at the time of heating and pressurization. Figure 4) deforms following the shape of the electronic component, thereby forming a defect-free electronic component protective layer. The hardener is more preferably contained at 3 to 45 parts by mass, and further preferably 5 to 40 parts by mass, relative to 100 parts by mass of the thermosetting resin.

[0152]

[0153] The electronic component protective layer preferably contains a particulate modifier. The particulate modifier is used mainly for the purpose of setting the root mean square height Sq, root mean square slope Sdq, and dynamic index (FI) of the electronic component protective layer to a desired range. In addition, by appropriately changing the kind and amount of the particulate modifier, the mechanical properties such as the elastic modulus, Young's modulus, and indentation hardness of the electronic component protective layer can be set to a good range.

[0154] The particulate modifier preferably has a DBP oil absorption amount of 15 to 400 ml / 100 g as defined by JIS K 6217-4. By having a DBP oil absorption amount of 15 to 400 ml / 100 g, the cutting adaptability can be improved. It is presumed that the improvement in cutting adaptability is caused by the following presumed action, but the action mechanism of the effect in the first embodiment is not limited by the presumed action.

[0155] The DBP oil absorption amount refers to the amount of DBP (dibutyl phthalate) that can be absorbed by the substance as the object, and can be used as an index for grasping the development degree of the aggregate of the particulate modifier described later.

[0156] The particulate modifier of the first embodiment forms a secondary particle-like aggregate (hereinafter, aggregate 22) by agglomeration, adhesion, or fusion of the fine particles (hereinafter, primary particles 21) as the base. Figure 3 Schematic diagram showing the aggregate of the particulate modifier.

[0157] (Presumed Action)

[0158] Hereinafter, the presumption of the action of the particulate modifier contributing to the improvement in cutting adaptability of the electronic component protective layer is shown. The primary particles 21 of the particulate modifier have a property of aggregating with each other by various inter-particle interactions such as electrostatic interaction, and the aggregate 22 is formed by agglomeration, adhesion, or fusion of the plurality of primary particles 21. When the primary particles are agglomerated, the primary particles 21 are not necessarily packed tightly, and a space 23 is generated in the aggregate 22.

[0159] ​When the particulate modifier is impregnated in a liquid such as oil or a polymer solution, low molecules or high molecules in the liquid enter the space 23 in the aggregate. If the high molecules enter the space 23, the molecular chains of the high molecules do not all enter the space 23, but only a part of the molecular chains enter the space 23. This phenomenon occurs at a plurality of ends in the high molecules, forming a state in which a plurality of particulate modifiers are connected by the high molecular chains. By forming this phenomenon in a large amount in the electronic part protective layer, a cross-linking-like structure is formed, the strength of the electronic part protective layer is increased, and the generation of a burr or a ragged edge at the time of cutting is suppressed.

[0160] The inference is affected by the size of the space in the aggregate. That is, the more the aggregate is developed and becomes large, the more difficult it is for the primary particles to be aggregated by close packing, and thus a wider space is formed, or more spaces are formed. As a result, the particulate modifier forms a cross-linking-like structure with a higher density, and the electronic part protective layer acquires a higher strength.

[0161] As an index for measuring the size of the space, the DBP oil absorption amount can be used. The DBP oil absorption amount is in a positive correlation with the amount of DBP (dibutyl phthalate) that can be absorbed by the substance as the object, that is, the total volume of the space in the aggregate. The higher the DBP oil absorption amount, the wider and more the space in the aggregate, and a cross-linking-like structure with a high density is formed in the electronic part protective layer.

[0162] The above is the inference in the improvement of the strength of the electronic part protective layer using the particulate modifier. The mechanism of the effect of the effect in the first embodiment is not limited by the inference.

[0163] The DBP oil absorption amount of the particulate modifier used in the first embodiment, which is specified by JIS K 6217-4, is 15 ml / 100 g to 400 ml / 100 g. By the DBP oil absorption amount of the particulate modifier being 15 ml / 100 g or more, the degree of development of the aggregate is sufficiently increased, and a sufficient cross-linking-like effect is produced. As a result, at the time of cutting processing of the electronic part mounting substrate on which the electronic part protective layer is laminated, the burr of the electronic part protective layer is suppressed. In addition, by the DBP oil absorption amount of the particulate modifier being 400 ml / 100 g or less, the intake of a large amount of high molecules into the particulate modifier is prevented, the generation of a region in which the high molecules are insufficient is suppressed, and at the time of cutting processing of the electronic part mounting substrate on which the electronic part protective layer is laminated, the occurrence of appearance defects such as cracking of the electronic part protective layer starting from the defects is suppressed. The DBP oil absorption amount of the particulate modifier is more preferably 30 ml / 100 g to 350 ml / 100 g, and further preferably 50 ml / 100 g to 250 ml / 100 g.

[0164] The content of the particulate modifier in the electronic component protective layer 100 is preferably 1 to 30 mass%. When the content of the particulate modifier is 1 mass% or more, sufficient crosslinking-like effects can be produced in the electronic component protective layer, and the cutting suitability is further improved. When the content of the particulate modifier is 30 mass% or less, a large amount of the high molecule is prevented from being taken into the particulate modifier, and a region in which the high molecule is insufficient is suppressed from being produced in the electronic component protective layer, and the cutting suitability is further improved. The content of the particulate modifier in the electronic component protective layer is further preferably 5 to 20 mass%.

[0165] As examples of the particulate modifier, there are no limitations as long as the particulate modifier has an effect of improving the cutting suitability of the electronic component protective layer, and examples include carbon-based particles such as carbon black, carbon nanotube, graphite, carbon fiber, and carbon nanosheet; and inorganic particles such as lithium phosphate (Li3PO4) described in Japanese Patent Laid-Open No. 2018 / 185938 and silica described in International Publication No. 2016 / 021467. Known substances can be used as long as the substances have an aggregation effect and a DBP oil absorption amount can be measured. Among them, carbon black is preferably used. Carbon black is a substance that is classified by a specific classification such as Ketjen black or acetylene black, and thus a substance that is not classified by the specific classification can also be included. These particulate modifiers do not excessively self-aggregate by entanglement like carbon nanotube that has a fibrous shape, and produce a strong interaction with the high molecule, and thus can be uniformly dispersed in the electronic component protective layer, and can suppress breakage at the time of cutting, and thus are preferable.

[0166] From the viewpoint of imparting insulating properties to the electronic component protective layer, the particulate modifier preferably has a volume resistivity of 1.0 x 10 -3 Ω·cm or more. The particulate modifier more preferably has a volume resistivity of 1.0 x 10 7 Ω·cm or more, and further preferably 1.0 x 10 13 Ω·cm or more. The volume resistivity of the substance contained in the particulate modifier can be measured according to JIS C2141. The upper limit of the volume resistivity is not limited, but is generally 1.0 x 10 17 Ω·cm or less.

[0167] The particulate modifier can be used alone or two or more kinds can be used in combination. By using two or more kinds of particulate modifiers in combination, the respective characteristics can be complemented. For example, when carbon black (DBP oil absorption amount: 100 ml / 100 g, volume resistivity: 1.6 x 10 -5 Ω·cm) is used as the first particulate modifier and silica (DBP oil absorption amount: 220 ml / 100 g, volume resistivity: 1.6 x 10 16In the case where the electronic component protective layer is formed by using a material containing carbon black (Ω·cm) as the second particulate modifier, the cutting adaptability and the recognition can be improved by the carbon black, and the cutting adaptability and the insulation breakdown voltage can be improved by the silicon dioxide.

[0168] Thickness of electronic component protective layer

[0169] From the viewpoint of improving the insulation breakdown voltage and thinning, the thickness of the electronic component protective layer is preferably 10 μm to 1000 μm. The thickness of the electronic component protective layer is more preferably 15 μm to 500 μm, and further preferably 20 μm to 250 μm.

[0170] Electronic component protective sheet

[0171] The electronic component protective sheet 6 is a precursor of the electronic component protective layer, and is a resin sheet having insulation. In the case where the electronic component protective sheet contains a thermally hardenable resin, the electronic component protective sheet is hardened by heating it for a prescribed time and at a prescribed temperature to cause a hardening reaction, and becomes the electronic component protective layer. With respect to the electronic component protective sheet, in order to protect the surface, a release sheet can be included on one side or both sides. In addition, a cushioning material used in the coating protection process using the electronic component protective sheet, which will be described later, can be laminated in advance.

[0172] Method for manufacturing electronic component protective sheet

[0173] The method for manufacturing the electronic component protective sheet is not particularly limited, and for example, a method in which a composition in which a material such as the adhesive resin that forms the electronic component protective layer is dissolved in a solvent or the like is applied to a release sheet can be exemplified. As the application method, for example, a gravure coater method, a kiss coater method, a die coater method, a lip coater method, a doctor blade method, a roll coater method, a knife coater method, a spray coater method, a bar coater method, a spin coater method, a dip coater method, or various printing methods can be exemplified.

[0174] In order to achieve a desired thickness, the electronic component protective sheet of the first embodiment can also laminate two or more electronic component protective sheets. With respect to a structure that is laminated as described above, the structure can be composed only of the electronic component protective sheet, or can include a layer having a specific function as an intermediate layer.

[0175] Use of electronic component protective sheet

[0176] The electronic component protection sheet of the first embodiment exhibits sufficient adhesion in practical use, regardless of whether the substrate is one of metal, resin, fiber, ceramic, glass, and electrically conductive silicon. As the metal, aluminum, copper, brass, stainless steel, iron, chromium, and the like can be used. As the resin, epoxy resin, polyethylene terephthalate, polyimide, polyamide, polyethylene, polypropylene, polyolefin-based graft polymer, polystyrene, polyvinyl chloride, and the like can be used. Thus, the electronic component protection sheet can also be preferably used for adhesion between dissimilar materials of different polarity.

[0177] The electronic component protection sheet of the first embodiment can be preferably used for protection of various substrates, namely, rigid substrates, flexible printed circuit (FPC) substrates, and the like.

[0178] The electronic component mounting substrate using the electronic component protection sheet of the first embodiment can be provided in electronic machines such as notebook personal computers (PCs), mobile phones, smartphones, tablet computer terminals, and the like, in addition to being provided in liquid crystal displays, touch panels, and the like.

[0179] Method for manufacturing electronic component mounting substrate

[0180] A method for manufacturing an electronic component mounting substrate using the electronic component protection sheet of the first embodiment (hereinafter, sometimes abbreviated as a coating protection method, a coating method, a protection method) will be described.

[0181] The electronic component mounting substrate of the first embodiment can be manufactured via the following steps: a step of mounting one or more electronic components on a substrate (step i); a step of preparing an electronic component protection sheet (step ii); a step of placing the electronic component protection sheet so as to be in contact with the highest electronic component among the electronic components (step iii, also referred to as a temporary adhesion step); a step of deforming the electronic component protection sheet along the shape of each electronic component and coating at least a portion of the electronic components and the substrate by heating and pressing (step iv); and a step of hardening the deformed electronic component protection sheet in the deformed state to form an electronic component protection layer (step v). Via these steps, an electronic component mounting substrate that is coated and protected by an electronic component protection layer formed from the electronic component protection sheet of the first embodiment can be obtained. Step iv and step v can also be provided as a series of steps.

[0182] Hereinafter, with respect to steps iii to v, the following will be used. Figure 4 An example of a coating protection method for an electronic component mounting substrate based on heating and pressing using an electronic component protection sheet will be described.

[0183] (Step iii: electronic component protection sheet placement step)

[0184] An electronic component mounting substrate (also referred to as a mounting substrate) 100 on which electronic components 2a and 2b are mounted using solder bumps 4 on a substrate 1 is prepared. The electronic components 2 are semiconductor chips, capacitors, transistors, inductors, thermal resistors, or the like, and are mounted on the substrate 1 via the solder bumps 4. A gap exists between the electronic components 2a, 2b and the substrate 1 due to the solder bumps 4. The electronic component 2a is designed to be higher than the electronic component 2b.

[0185] Subsequently, an electronic component protection sheet 6 cut to a predetermined size is placed on the mounting surface of the electronic components 2a, 2b. Since the height of the electronic component 2a is greater than that of the electronic component 2b, the electronic component protection sheet 6 comes into contact with the electronic component 2a and is temporarily attached. Further, there is a case where the electronic component protection sheet 6 is bent to come into contact with the electronic component 2b (not shown in the figure). Figure 4

[0186] Further, a cushioning material 7 can be stacked on the electronic component protection sheet 6. Figure 4 An example in which a cushioning material is used is shown. The cushioning material 7 can be stacked after the electronic component protection sheet 6 is placed, or a stack in which the electronic component protection sheet 6 and the cushioning material 7 are overlapped in advance can be placed. The cushioning material 7 is a material that softens or melts when heated and pressurized, and has a function of promoting the followability of the electronic component protection sheet 6 to the electronic components 2a, 2b and the gap between the electronic components.

[0187] The cushioning material 7 is not particularly limited as long as it is a raw material having thermoplasticity, but it is preferable to have a melting temperature and a glass transition point (Tg) that are lower than the temperature at the time of pressurization. As preferable examples, a polyolefin film, a vinyl chloride film, and a polyvinyl alcohol (PVA) film can be exemplified. The thickness of the cushioning material is usually about 100 μm to 1 mm, although it depends on the depth of the groove formed between the electronic components 2a and 2b. In the case where a plurality of cushioning materials 7 are stacked, it is preferable that the total thickness be within the range.

[0188] Further, the electronic component mounting substrate shown in the first embodiment is an example, and the structure of the electronic components and the substrate is not particularly limited, and a gap can exist or can not exist between the electronic components 2a, 2b and the substrate 1. The arrangement position of the mounted electronic components is not limited.

[0189] ​Subsequently, the electronic component protection sheet 6 is deformed by heating and pressurization using the heating and pressurization machine 20, and deforms in a manner following the shapes of the respective electronic components, that is, in a manner following the upper surfaces and side surfaces of the electronic component 2a and the electronic component 2b, and follows at least a portion of the electronic components and the substrate 1. The cushioning material 7 is softened or melted by heat, thereby facilitating the following of the electronic component protection sheet 6 to the concavities and convexities between the electronic components on the mounting substrate 100.

[0190] Also preferred is a method in which a peeling sheet is interposed between the heating and pressurization machine 20 and the cushioning material 7 at the time of heating and pressurization. The peeling sheet is a sheet in which a known peeling treatment is performed on a base material such as paper or plastic. Also, a plastic sheet having low polarity such as Teflon (registered trademark) can be used.

[0191] The heating temperature is a temperature at which the electronic component protection sheet 6 is moderately softened and deformed in a manner following the shapes of the respective electronic components and enters the gaps between the respective electronic components, and is preferably 100°C to 260°C, and more preferably 120°C to 240°C. If the temperature is too low, the entering property of the electronic component protection sheet 6 into the gaps between the mounted respective electronic components decreases. On the other hand, if the temperature is too high, the thermal hardening reaction of the heat-hardening resin of the electronic component protection sheet 6 rapidly proceeds, and the entering property of the electronic component protection sheet into the gaps between the mounted electronic components decreases.

[0192] The pressure at the time of heating and pressurization is preferably 0.01 MPa to 10 MPa, and more preferably 0.1 MPa to 6.0 MPa. By heating and pressurizing at the pressure, the electronic components are not damaged, and the embedding property is further improved.

[0193] The heating time is usually in the range of 0.5 minutes to 30 minutes, and preferably 1 minute to 20 minutes. If the heating time is too short, the entering property of the electronic component protection sheet into the gaps between the mounted electronic components decreases. On the other hand, if the time is too long, the heat-hardening resin is likely to be thermally decomposed or oxidized, and the reliability of the bonding site due to the reaction product or the like decreases. The heating and pressurization process is preferably performed in a vacuum state.

[0194] As a method of heating and pressurization, in addition to the use of a heating and pressurization machine, a method in which a metal plate having a moderate weight is stacked to achieve a prescribed pressure, and the stack is put into an oven is also preferred.

[0195] On the other hand, as a heating and pressurization method other than a heating and pressurization machine, a vacuum forming method or a vacuum pressure forming method is also preferred.

[0196] (Process v: hardening process of the deformed electronic component protection sheet)

[0197] After the heating and pressurization in a state where the electronic component protection sheet 6 is deformed, further heating at a temperature of 150°C to 230°C for 10 minutes to 60 minutes is performed, thereby thermally hardening the thermally hardenable resin in the electronic component protection sheet 6 to form an electronic component protection layer as a hardened film. The electronic component protection layer is firmly adhered to the electronic component and the substrate, and functions as a protection layer for protecting the electronic component from damage due to external impact or scratches. Further, by setting the temperature of the heating and pressurization to 150°C or higher and the time to 30 minutes or more at the stage of (step iv), thermal hardening can be completed to form a coating protection layer. In order to prevent short-circuiting between electronic components, the coating protection layer must be an insulator, and a surface resistance value of 1 x 10 7 Ω / Υ or more is required. Further, in the case where a thermoplastic resin is used instead of a thermally hardenable resin, step v can be omitted.

[0198] In the electronic component mounting substrate of the first embodiment, the electronic component protection layer can be the outermost layer, or other functional layers can be further laminated. The other functional layers are, for example, layers having functions of conductivity, hard coat property, water vapor barrier property, oxygen barrier property, thermal conductivity, low dielectric constant, high dielectric constant property, or heat resistance. Among them, the conductive layer is sometimes used for the purpose of protecting the coated electronic component from the influence of electromagnetic wave noise.

[0199] Figure 5 An example of the structure of the electronic component mounting substrate 11 having a conductive layer is shown in FIG. 6. The conductive layer 8 is formed on the upper layer of the electronic component protection layer 3 and connected to the ground 9. The connection point to the ground 9 can be present on the surface of the substrate 1, or on the side surface of the substrate 1. The conductive layer can be formed by, for example, forming a metal layer on the surface of the electronic component protection layer by sputtering or plating, or laminating a conductive sheet containing conductive particles on the electronic component protection layer.

[0200] Electronic device

[0201] The electronic component mounting substrate of the first embodiment is preferably used not only in liquid crystal displays, touch panels, and the like, but also in electronic devices such as notebook personal computers, mobile phones, smartphones, tablet computer terminals, and the like.

[0202] [Second Embodiment]

[0203] Next, an example of an electronic component mounting substrate different from the first embodiment will be described. Further, in the following description, the same reference signs are assigned to the same elements as those of the first embodiment, and the description thereof will be appropriately omitted. In the electronic component mounting substrate of the second embodiment, the description of the first embodiment is applied except for the following additional description.

[0204] Electronic component protection layer

[0205] The electronic component protective layer of the second embodiment is used to coat and protect electronic components mounted on a substrate, like the first embodiment.

[0206] "Root mean square height Sq"

[0207] Sq is a surface property parameter defined by the equation (4) in ISO 25178-2:2012. The description of the equation and the like refer to the description of the first embodiment.

[0208] Also, during the period from the manufacture of the electronic component mounting substrate to the assembly into an electronic machine, the electronic component protective layer sometimes suffers from scratches due to, for example, the contact of the electronic component mounting substrates with each other. The electronic component mounting substrate is often discarded by visual judgment that the electronic component protective layer has scratches because it is assembled in a precision machine. For example, there are cases where such electronic component mounting substrates with scratches are judged to be unusable by visual determination. However, a part of the discarded products is a slight scratch, and even an article that is not a problem in practical use is included.

[0209] The surface of the electronic component protective layer in the second embodiment is preferably a root mean square height Sq of 0.01 μm to 10 μm calculated in accordance with ISO 25178-2:2012. By making the surface of the electronic component protective layer be in the range, a moderate concave-convex can be imparted to the electronic component protective layer. As a result, even if a foreign matter comes into contact with the surface of the electronic component protective layer and damages the surface thereof, a slight scratch that is not a problem in practical use is not easily visually recognized in appearance because the surface as a whole is concave-convex. The root mean square height Sq of the electronic component protective layer is more preferably 0.05 μm to 7 μm, and further preferably 0.1 μm to 5 μm.

[0210] "Root mean square slope Sdq"

[0211] The description of the root mean square slope Sdq of the second embodiment refers to the description of Sdq of the first embodiment except for the following aspects.

[0212] The root mean square slope Sdq of the surface of the electronic component protective layer in the second embodiment is set to 0.0001 to 5 according to ISO 25178-2:2012. By the surface of the electronic component protective layer being in the range, the stain resistance of the electronic component protective layer can be improved. By setting the root mean square slope Sdq to 0.0001 or more, a moderate concave-convex slope can be imparted to the electronic component protective layer, and the adhesion of dust or dirt can be suppressed. On the other hand, by setting the root mean square slope Sdq to 5 or less, fine dust or dirt can be suppressed from adhering to the concave-convex wall surface of the electronic component protective layer. The root mean square slope Sdq of the electronic component protective layer is more preferably 0.0005 to 4.5, further preferably 0.001 to 4, and particularly preferably 0.005 to 3.5.

[0213] Further, the present inventors have made diligent studies, and as a result, have found that by setting the root mean square slope Sdq of the surface of the electronic component protective layer to 0.005 to 3.5, the moisture transpiration property is improved. The electronic component mounting substrate is used in various temperature environments after being assembled into an electronic machine, and thus the electronic component protective layer is sometimes exposed to a high humidity environment. In the case where the root mean square slope Sdq of the surface of the electronic component protective layer is 0.005 or more, the fine water droplets generated by the adhesion of moisture in the atmosphere to the surface of the electronic component protective layer do not become large by being blocked by the concave-convex surface, but rather rapidly evaporate into the atmosphere. On the other hand, in the case where the root mean square slope Sdq of the surface of the electronic component protective layer is 3.5 or less, the fine water droplets are not blocked by the steep concave-convex surface of the electronic component protective layer, but rather rapidly evaporate into the atmosphere.

[0214] By shortening the time for which the water droplets adhering to the surface of the electronic component protective layer remain on the surface, the penetration of moisture into the electronic component protective layer can be suppressed, and the moisture from reaching the electronic component positioned in the lower layer of the electronic component protective layer to cause a short circuit or the like.

[0215] The surface of the electronic component protective layer of the second embodiment is preferably a root mean square height Sq of 0.01 μm to 10 μm according to ISO 25178-2:2012, and satisfies the following mathematical expression (2) and mathematical expression (3).

[0216] y ≦ 195x - 0.553 (2)

[0217] y ≧ 0.258x (3)

[0218] (x: root mean square slope Sdq of the surface of the electronic component protective layer according to ISO 25178-2:2012, y: root mean square height Sq of the surface of the electronic component protective layer according to ISO 25178-2:2012)

[0219] When a foreign object contacts the surface of the electronic component protective layer and damages the surface, slight damage that is not easily visually recognized to the extent that is practically acceptable can be reduced, and thus the production efficiency can be improved.

[0220] Dynamic index (FI)

[0221] The FI is a parameter calculated using the equation (1) described in the first embodiment, and the measurement method is JIS Z 8781-4 described in the first embodiment, except for the following description, and the description of the FI of the first embodiment is also applied.

[0222] (Effect of FI)

[0223] The FI of the surface of the electronic component protective layer of the second embodiment is preferably 0.3 to 80. By setting the FI to the range, the cutting adaptability and the voltage resistance (insulation breakdown voltage) of the electronic component protective layer are good. By the FI being 0.3 or more, a certain order can be given to the concave-convex shape of the surface of the electronic component protective layer. By giving a certain order to the concave-convex shape of the surface when a voltage is applied to the electronic component protective layer, the starting point of the insulation breakdown can be suppressed, and thus the voltage resistance (insulation breakdown voltage) is improved. On the other hand, by the FI of the surface of the electronic component protective layer being 80 or less, a certain disorder can be given to the concave-convex shape of the surface. In a surface in which the concave-convex shape has a high order, external stress applied by cutting or the like tends to concentrate on a specific portion, but in the case where the concave-convex shape has a certain disorder, the external stress can be appropriately dispersed, and thus the cutting adaptability is improved. The FI of the surface of the electronic component protective layer is more preferably 1 to 75, further preferably 3 to 50, and particularly preferably 5 to 26.

[0224] The "control method of Sq, Sdq, and FI", "OD value", "L * a * b * value" of the second embodiment are applied to the description of the [control method of Sq, Sdq, and FI], [optical density (OD value)], and [L * a * b * value] of the first embodiment.

[0225] The "insulation property" of the second embodiment is applied to the description of the "insulation property of the electronic component protective layer" of the first embodiment.

[0226] The "binder resin", "thermoplastic resin", "thermosetting resin", and "hardening agent" of the second embodiment are applied to the description of the [binder resin], [thermoplastic resin], [thermosetting resin], and [hardening agent] of the first embodiment.

[0227] Particulate modifier

[0228] The electronic component protective layer preferably contains a particulate modifier. The particulate modifier is used mainly for the purpose of setting the root mean square height Sq, the root mean square slope Sdq, and the dynamic index (FI) of the electronic component protective layer to a desired range. In addition, by appropriately changing the kind and the amount of addition of the particulate modifier, the mechanical properties such as the elastic modulus, the Young's modulus, and the indentation hardness of the electronic component protective layer can be set to a good range.

[0229] The particulate modifier preferably has a DBP oil absorption amount of 15 ml / 100 g to 400 ml / 100 g as defined by JIS K 6217-4. By the DBP oil absorption amount of the particulate modifier being 15 ml / 100 g to 400 ml / 100 g, the cutting adaptability can be improved. It is presumed that the improvement in the cutting adaptability is caused by the effects described in the first embodiment.

[0230] The particulate modifier of the second embodiment adopts the description of the first embodiment using Figure 3 The preferred range of the DBP oil absorption amount of the surface modifier as defined by JIS K 6217-4, the content rate of the particulate modifier in 100 mass% of the electronic component protective layer, the specific examples of the particulate modifier, the preferred kinds, and the volume resistivity of the particulate modifier of the second embodiment adopt the description of the first embodiment.

[0231] The "thickness of the electronic component protective layer", the "electronic component protective sheet", the "manufacturing method of the electronic component protective sheet", and the "use of the electronic component protective sheet" of the second embodiment adopt the description of the "thickness of the electronic component protective layer", the "electronic component protective sheet", the "manufacturing method of the electronic component protective sheet", and the "use of the electronic component protective sheet" of the first embodiment.

[0232] The "manufacturing method of the electronic component mounting substrate" and the "electronic machine" of the second embodiment adopt the description of the "manufacturing method of the electronic component mounting substrate" and the "electronic machine" of the first embodiment.

[0233] [Examples]

[0234] Hereinafter, the present disclosure will be described in detail by citing examples and comparative examples, but the present disclosure is not limited only to the following examples. Further, the following "parts" and "%" are values based on "mass parts" and "mass %".

[0235] In Tables 1 to 7, for example, the index expression part of "2.2 x 10 9 " is written as "2.2 x 10^9".

[0236] <Raw Materials>

[0237] The raw materials used in the examples are shown below.

[0238] <Thermosetting resin>

[0239] [Synthesis of thermosetting resin 1]

[0240] A glass-made flask including a stirrer, a thermometer, a reflux cooler, a nitrogen introduction tube, and a pressure reducing device was charged with terephthalic acid 166 parts, adipic acid 146 parts, 3-methyl-l,5-pentanediol 212 parts, and ethylene glycol 25 parts, and stirring was performed while circulating nitrogen gas, and the temperature was slowly increased under normal pressure, and reaction was performed at 200°C to 230°C for about 8 hours, and a liquid material having an acid value of 43 was obtained. Next, tetra-n-butoxytitanium 0.01 part was charged, and after nitrogen replacement was performed, stirring was performed at 180°C for 30 minutes under a closed condition. Next, reaction was performed at 230°C under 5 mmHg for 2 hours, and a polyester diol having an acid value of 1.1, a hydroxyl value of 114.2, a molecular weight of 982, and a color phase of 10 (American Public Health Association (APHA) method, hereinafter the same) was obtained.

[0241] Next, a reaction vessel including a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube was charged with the polyester diol 734 parts, dimethylolpropionic acid 23.9 parts, toluene diisocyanate 219 parts, and toluene 242 parts, and reaction was performed at 50°C for 8 hours under a nitrogen environment. Toluene 1200 parts was added thereto, and a solution of a urethane prepolymer having an isocyanate group at the terminal was obtained.

[0242] Next, the obtained solution of the prepolymer was warmed to 70°C, and a solution in which 1,3-diaminopropane 20.0 parts, benzylamine 3.1 parts, 2-propanol 600 parts, and toluene 961 parts were mixed was added dropwise over 1 hour while maintaining the temperature. Further reaction was performed at 70°C for 6 hours after the addition was completed, and thus a polyurethane-based resin having a molecular weight (Mw) of 130000, an acid value of 10 mgKOH / g, a Tg of 20°C, and a solid content of 25% was obtained.

[0243] Hardener 1: Bisphenol A type epoxy compound "jER828" (epoxy equivalent = 189 g / eq) manufactured by Mitsubishi Chemical Corporation

[0244] <Particle modifier>

[0245] • Particle modifier 1: Carbon black "MA100" (average primary particle diameter: 24 nm, DBP oil absorption: 100 ml / 100 g, volume resistivity: 1.6 x 10 -5 Ω·cm) manufactured by Mitsubishi Chemical Corporation

[0246] • Particulate modifier 2: Silica "Ultrasil U360" (DBP oil absorption: 220 ml / 100 g, volume resistivity: 1.6 x 10 16 Ω·cm) manufactured by NANOCYL

[0247] <Average primary particle diameter of particulate modifier>

[0248] The average primary particle diameter of the particulate modifier is calculated from the average of 20 primary particles that can be observed from an image amplified to about 50,000 to 1,000,000 times by a transmission electron microscope (TEM). Further, in the case where the particle shape of the particulate modifier has an average aspect ratio (length of long axis / length of short axis) of 1.5 or more, the average primary particle diameter is calculated by averaging the length of long axis.

[0249] <DBP oil absorption of particulate modifier>

[0250] The DBP oil absorption of the particulate modifier is measured in accordance with JIS K 6217-4. An absorptometer (absorptometer S-500, manufactured by Sanko Total Research Co., Ltd.) is used in the measurement.

[0251] <Manufacture of electronic component protection sheet>

[0252] [Manufacture of electronic component protection sheet]

[0253] A composition was obtained by charging 100 parts of thermohardening resin 1 (solid content), 15 parts of hardener 1, 2 parts of particulate modifier 1, and 4 parts of particulate modifier 2 into a container, adding a mixed solvent of toluene:isopropyl alcohol (mass ratio 2:1) so that the nonvolatile content concentration becomes 45 mass%, and stirring for 10 minutes using a disperser. The composition was applied to a buffer material using a doctor blade so that the dry thickness becomes 40 μm. Then, drying was performed at 100°C for 2 minutes, thereby obtaining a laminate sheet of the buffer material and the electronic component protection sheet of Example 101.

[0254] Laminate sheets of Examples 102 to 108, Examples 201 to 212, Examples 301 to 332, and Comparative Examples 101, 102, Comparative Examples 201 to 203, and Comparative Examples 301 to 304 were obtained by the same work as the electronic component protection sheet, except that the formulation amounts of Table 1 were changed. The formulation amounts of each example are shown in Tables 1 to 7.

[0255] [Manufacture of electronic component mounting substrate]

[0256] (Manufacture of mounting substrate)

[0257] A substrate on which a mold-sealed electronic component (1000 μm x 1000 μm) was mounted in a 5 x 5 array was prepared. The thickness of the substrate was 0.3 mm, and the mold-sealing thickness, i.e., the height (component height) from the top surface of the substrate to the top surface of the mold-sealing material, was 0.7 mm. Then, a half cut was made along the groove that was the gap between the components, and a mounting substrate was obtained (see FIG. 1). Figure 6 The half-cut groove depth was set to 0.8 mm (cut groove depth of the substrate was 0.1 mm), and the half-cut groove width was set to 200 μm.

[0258] The laminated sheets of each of the examples and the comparative examples were thermocompression-bonded to the mounting substrate (substrate on which electronic components were mounted in a 5 x 5 array) at 8 MPa and 170°C for 5 minutes, and the cushioning material was peeled off by hand. Then, curing was performed at 180°C for 2 hours, and the electronic component mounting substrate was treated so that Sq, Sdq, and FI became predetermined values based on Table 1, and the electronic component mounting substrate of each of the examples and the comparative examples was obtained.

[0259] Measurement of Root Mean Square Height Sq and Root Mean Square Slope Sdq

[0260] The root mean square height Sq and the root mean square slope Sdq of the electronic component protective layer were measured by the following method. First, the surface of the electronic component protective layer in the electronic component mounting substrate was measured using a laser microscope (manufactured by Keyence, model number: VK-X100). Then, the measured data was input to analysis software (analysis application "VK-H1XA" including ISO 25178 surface texture measurement module "VK-H1XR", both manufactured by Keyence), and ISO 25178 surface texture measurement was performed to calculate Sq and Sdq. (Conditions: S-filter: 1 μm, L-filter: 0.2 mm).

[0261] Measurement of Dynamic Index (FI)

[0262] First, the surface of the electronic component protective layer in the electronic component mounting substrate was measured using a multi-angle colorimeter (manufactured by BYK, model number: BYK-mac i23 mm measurement aperture). Then, L * 15° , L * 45° , L * 110° was measured. Then, FI was calculated based on Equation (1). The measurement was performed under the conditions that the light source was D50 and the field of view was 2° field of view. In Tables 5 to 7, L * is L *45° The value of OD.

[0263] Measurement of Optical Density (OD value)

[0264] The OD value of the surface of the electronic component protection layer in the electronic component mounting substrate was measured using "361T Tabletop Transmittance Concentration Meter" manufactured by X-Rite Co.

[0265] Measurement of a * b *

[0266] The a * b * value of the surface of the electronic component protection layer in the electronic component mounting substrate was measured using "Color Difference Meter CR-400" manufactured by KONICA MINOLTA Co.

[0267] Measurement of Surface Resistance Value

[0268] The surface resistance value of the electronic component protection layer in the electronic component mounting substrate was measured using "Hiresta-UX MCP-HT800 High Resistance Resistivity Meter" manufactured by Nittoseiko Analytech Co.

[0269] Evaluation

[0270] [Insulation Breakdown Voltage]

[0271] The cushion material of the laminated sheet in which the cushion material and the electronic component protection sheet were laminated was changed to a release sheet, and an electronic component protection sheet with a release sheet was produced.

[0272] One release sheet was peeled from the electronic component protection sheet with a release sheet, and was overlapped with an aluminum plate, and was heat-pressed at 180°C, 2 MPa for 10 minutes, and was cured at 180°C for 2 hours, thereby producing a test sheet. Then, it was left at 25°C, 50% RH for one night. Then, the withstand voltage (insulation breakdown voltage) was measured using a TM650 withstand voltage tester (manufactured by Tsuruhachi Electric Co.) under the same environment.

[0273] +++ : Insulation breakdown voltage is 2.0 kV or more.

[0274] ++ : Insulation breakdown voltage is 1.5 kV or more and less than 2.0 kV.

[0275] + : Insulation breakdown voltage is 1.0 kV or more and less than 1.5 kV. (Practical level)

[0276] NG : Insulation breakdown voltage is less than 1.0 kV. ​

[0277] [Cutting suitability]

[0278] The occurrence of burrs when singulating (full cutting) the electronic component mounting substrate of each example and comparative example was evaluated using a laser microscope and by the following criteria.

[0279] +++ : No collapse and burr were confirmed.

[0280] ++ : Collapse and / or burr occurred in less than 2 of 25 singulated electronic component mounting substrates.

[0281] + : Collapse and / or burr occurred in more than 2 but less than 5 of 25 singulated electronic component mounting substrates. (Practical level)

[0282] NG : Collapse and / or burr occurred in more than 5 of 25 singulated electronic component mounting substrates.

[0283] [Evaluation]

[0284] [Antifouling property]

[0285] The electronic component mounting substrate of each example and comparative example was subjected to a dust test machine (DT-1-CF, Suga Test Instruments Co., Ltd.) and exposed to dust for 60 minutes. As the test powder, 11 types of test powder (Kanto loam) prescribed by JIS Z 8901 were used.

[0286] After the dust-exposed test sample was taken out, the accumulated dust was removed using an air duster, and each of the 5 x 5 array-shaped sections was observed one by one, and the presence or absence of residual dust was confirmed, and the evaluation was performed in the following manner.

[0287] +++ : No dust was found in any section.

[0288] ++ : Dust was found in more than 1 but less than 3 of 25 sections.

[0289] + : Dust was found in more than 3 but less than 5 of 25 sections. (Practical level)

[0290] NG : Dust was found in more than 5 of 25 sections.

[0291] [Moisture transpiration property]

[0292] The moisture transpiration property was evaluated by simulating the number of times of leak contact of the circuit substrate of the electronic component mounting substrate. Referring to Figures 7A-7C The moisture transpiration test method is described. First, by performing etching treatment on a laminate of a copper foil having a thickness of 12 μm and a polyimide film having a thickness of 25 μm,Figure 7A A cathode electrode comb-shaped signal wiring 32 including a cathode electrode connection point 32' and an anode electrode comb-shaped signal wiring 33 including an anode electrode connection point 33' each having a line / space = 0.05 mm / 0.05 mm were formed on the polyimide film 31, as shown in a plan view.

[0293] Subsequently, as shown in a plan view, Figure 7B The laminated sheets of each of the examples and the comparative example, which covered the cathode electrode comb-shaped signal wiring 32 and the anode electrode comb-shaped signal wiring 33 and were cut to a size such that the cathode electrode connection point 32' and the anode electrode connection point 33' were exposed to the vicinity thereof, were thermocompression-bonded at 8 MPa and 170°C for 5 minutes, and the buffer material was peeled off by hand. Then, curing was performed at 180°C for 2 hours, and the test wiring board to which surface polishing or the like was required was treated to make Sq, Sdq, and FI prescribed values based on Table 1, and a test wiring board of each of the examples and the comparative example, on which the electronic component protection layer 3 was laminated, was obtained. With respect to the obtained test sample, a voltage of 50 V was applied for 500 hours under an environment of 85°C-85% RH (relative humidity) on the basis that the anode electrode was connected to the anode electrode connection point 33' and the cathode electrode was connected to the cathode electrode connection point 32'. Then, the change in resistance value before 500 hours was continuously measured, and the number of times of leakage contact was confirmed. Further, the "leakage contact" described below means that there is insulation breakdown due to short circuit, and the resistance instantaneously decreases and current flows. The evaluation criteria are shown below.

[0294] +++: No leakage contact.

[0295] ++: One time of leakage contact.

[0296] +: Two times of leakage contact. (Practical level)

[0297] NG: Three or more times of leakage contact.

[0298] [Identification]

[0299] (Production of test single sheets)

[0300] A substrate on which an electronic component (1000 μm x 1000 μm) subjected to mold sealing was mounted in a 5 x 5 array on a substrate including an epoxy glass was prepared. The thickness of the substrate was 0.3 mm, and the mold sealing thickness, that is, the height (height of the component) H from the top surface of the substrate to the top surface of the mold sealing material was 0.7 mm. Then, half-cutting was performed along a groove that was a gap between the components, and a test substrate was obtained (see FIG. 1). Figure 6). The half-cut groove depth was set to 0.8 mm (the cut groove depth of the substrate was 0.1 mm), and the half-cut groove width was set to 200 μm. The electronic component protection sheets of each example and comparative example were thermocompression-bonded to the test substrate under conditions of 8 MPa and 170°C for 5 minutes, and the buffer was peeled off by hand. Then, curing was performed at 180°C for 2 hours, and the electronic component mounting substrate to which surface polishing or the like was required was treated so as to make Sq, Sdq, and FI prescribed values based on Table 1, thereby obtaining the electronic component mounting substrate of each example and comparative example. Then, the obtained electronic component mounting substrate was full-cut along the half-cut groove, and 25 test pieces were obtained for each example and comparative example. Further, the same operation was performed without laminating the electronic component protection sheet, thereby obtaining a test piece without the electronic component protection layer.

[0301] (Identification Evaluation)

[0302] Ten groups were prepared by combining one test piece with the electronic component protection layer and one test piece without the electronic component protection layer as one group for each. Then, the number of groups in which the test piece with the electronic component protection layer and the test piece without the electronic component protection layer could be distinguished was counted. The observation was performed visually and the evaluation was performed by the following criteria.

[0303] +++ : All of the 10 groups could be distinguished.

[0304] ++ : The number of groups that could be distinguished was 8 or more but less than 9.

[0305] + : The number of groups that could be distinguished was 6 or more but less than 8. (Practical level)

[0306] NG : The number of groups that could be distinguished was less than 6.

[0307] [Resistance to Cold-heat Cycles]

[0308] The test pieces were produced by the same method as the [Identification] evaluation, and the resistance to cold-heat cycles was evaluated.

[0309] The test pieces with the electronic component protection layer were subjected to 1000 times of alternating exposure under exposure conditions of high-temperature exposure: 125°C for 15 minutes, and low-temperature exposure: -50°C for 15 minutes, using a cold-heat shock device ("TSE-11-A", manufactured by ESPEC Corporation). Then, the test pieces were taken out, the appearance of the electronic component protection layer was observed, and the number of broken test pieces was counted, and the evaluation was performed by the following criteria. The number of test pieces was 10 for each example.

[0310] +++ : The number of broken test pieces was 0.

[0311] ++: The number of test pieces damaged is more than 1 and less than 2.

[0312] +: The number of test pieces damaged is more than 3 and less than 5. (Practical level)

[0313] NG: The number of test pieces damaged is more than 6.

[0314] Evaluation

[0315] [Scratch visibility]

[0316] On a polyimide film (Toray Dupont's "Kapton 500H") having a thickness of 125 μm, each of the layered sheets of the examples and comparative examples cut into 5 cm x 15 cm was placed, and after heat-pressing at 180°C, 2 MPa for 10 minutes, the buffer material was peeled off, and curing was performed at 180°C for 2 hours, thereby obtaining a test substrate. Subsequently, for the electronic component protection layer, on an abrader (manufactured by Test Machine Industry Co., Ltd.), under conditions of a load of 10 gf, a stroke of 120 mm, and a reciprocating speed of 10 times / min, the friction member was reciprocated 10 times, and then the surface of the electronic component protection layer was visually observed, and evaluation was performed based on the following criteria.

[0317] +++ : The number of scratches that could be confirmed was less than 10.

[0318] ++: The number of scratches that could be confirmed was more than 10 and less than 20.

[0319] +: The number of scratches that could be confirmed was more than 20 and less than 40. (Practical level)

[0320] NG: The number of scratches that could be confirmed was more than 40.

[0321]

[0322] [Table 2

[0323]

[0324] [Table 3]

[0325]

[0326] [Table 4]

[0327]

[0328]

[0329]

[0330]

[0331] Industrial applicability

[0332] The electronic component mounting substrate of the present disclosure can be used by being mounted in an electronic machine. The electronic component protection sheet of the present disclosure can preferably be used as a sheet for protecting an electronic component in an electronic mounting substrate. The protection sheet can not only be preferably used as an electronic component, but also preferably used as a component protection sheet for coating various components.

Claims

1. An electronic component mounting substrate, wherein an electronic component is mounted on the substrate and the electronic component is covered by an electronic component protective layer, wherein the dynamic index (FI) of the surface of the electronic component protective layer, calculated using formula (1), is 0.3 to 80. L * 15° L * 45° L * 110° The L values, as specified in Japanese Industrial Standard Z8781-4, represent the offset angles of the orthographically reflected light from light incident at an angle of 45° relative to the perpendicular direction of the electronic component surface, with angles of 15°, 45°, and 110° respectively. * a * b * L in color scheme * .

2. The electronic component mounting substrate according to claim 1, characterized in that... The optical density (OD value) of the protective layer for the electronic components is 1 to 6 in the 360nm to 760nm range, as specified by the International Organization for Standardization (ISO) 5-2.

3. The electronic component mounting substrate according to claim 1 or 2, characterized in that... The protective layer for the electronic components is L as specified in Japanese Industrial Standard Z8781-4. * a * b * L in the color system * The value is 1 to 50, and a * The value is between -10 and 10, and b * The value ranges from -10 to 10.

4. The electronic component mounting substrate according to claim 1 or 2, characterized in that... The surface resistivity of the protective layer for the electronic component is 1.0 × 10⁻⁶. 7 Ω / γ or higher.

5. The electronic component mounting substrate according to claim 1 or 2, characterized in that... The protective layer for the electronic components contains an adhesive resin and a granular modifier. The granular modifier has an oil absorption capacity of 15 ml / 100g to 400 ml / 100g as specified in Japanese Industrial Standard K 6217-4 for dibutyl phthalate.

6. The electronic component mounting substrate according to claim 5, characterized in that... The granular modifier contains at least one type of carbon black.

7. An electronic machine, equipped with an electronic component mounting substrate according to any one of claims 1 to 6.

8. An electronic component protective sheet for covering electronic components mounted on a substrate, wherein the electronic component protective sheet, The surface of the hardened film formed by heating the electronic component protective sheet at 180°C for 60 minutes, The dynamic index (FI) calculated using equation (1) is 0.3–80. L * 15° L * 45° L * 110° The L values, as specified in Japanese Industrial Standard Z8781-4, represent the offset angles of the orthographically reflected light from light incident at an angle of 45° relative to the perpendicular direction of the electronic component surface, with angles of 15°, 45°, and 110° respectively. * a * b * L in color scheme * .

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