JP2012151296A - Component mounted with electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a problem that is caused by solidification shrinkage of a sealing resin, caused by using a thermoplastic resin, while using the thermoplastic resin to enhance productivity of a resin-sealed electronic component.SOLUTION: A foamed thermoplastic resin is used as a resin seal material, and a shape of an outer periphery of a cross section, perpendicular to a substrate, of a sealing resin part is designed to assume an arc shape. Preferably, the arc shape is an approximately perfect circle-like arc shape. Preferably, a surface of the sealing resin part is formed as an approximately perfect spherical surface. In addition, preferably, the foamed thermoplastic resin is mainly composed of a low-melting-point and high-fluidity polybutylene terephthalate resin.

Description

  The present invention relates to an electronic component mounting component.

  As a sealing technique for protecting electronic components such as ICs, capacitors, and diodes from mechanical and electrical external environments, resin sealing that is inexpensive and has excellent mass productivity is known.

  As a resin sealing method, first, a semiconductor element mounted on a substrate is set in a mold, and then a resin for sealing is melted and injected into the mold. Finally, a method of demolding after curing the resin is known.

  As a resin for sealing an electronic component such as an IC, a thermosetting resin such as a phenol resin, an epoxy resin, or a silicone resin is used (for example, see Patent Document 1). These thermosetting resins are excellent in adhesion to ceramics and metals, and are excellent in heat resistance and chemical resistance. Therefore, the thermosetting resin is suitable as a material for sealing an electronic component such as an IC.

  However, since the time for curing the thermosetting resin is very long, if the thermosetting resin is used as a material for sealing an electronic component such as an IC, the productivity of the resin-encapsulated electronic component is lowered. .

  In order to increase the productivity of resin-sealed electronic components, it is conceivable to use a thermoplastic resin instead of a thermosetting resin. However, when the sealing resin is molded with a thermoplastic resin, the shrinkage stress tends to concentrate on the electronic component due to solidification shrinkage of the sealing resin. If the shrinkage stress is concentrated on the electronic component, the electronic component may be damaged.

Japanese Patent Laid-Open No. 05-3218

  The present invention has been made to solve the above-mentioned problems, and the object thereof is to use a thermoplastic resin while using a thermoplastic resin in order to increase the productivity of resin-sealed electronic components. This is to suppress problems caused by solidification shrinkage of the sealing resin.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, the present inventors have found that the above problems can be solved if a foamed thermoplastic resin is used as the resin sealing material and the outer peripheral shape of the cross section perpendicular to the base material of the sealing resin portion is an arc shape. The invention has been completed. More specifically, the present invention provides the following.

  (1) A base material, an electronic component mounted on the surface of the base material, and a sealing resin portion that seals the electronic component, wherein the sealing resin portion is made of a foamed thermoplastic resin. An electronic component mounting component in which the outer peripheral shape of the surface of the sealing resin portion in a cross section perpendicular to the base material of the sealing resin portion is an arc shape.

  (2) The electronic component mounting component according to (1), wherein the outer peripheral shape is a substantially circular arc.

  (3) The electronic component mounting component according to (1) or (2), wherein the surface of the sealing resin portion is substantially spherical.

  (4) A method for manufacturing an electronic component mounting component according to any one of (1) to (3), wherein an electronic component mounted on a surface of a substrate is fixed in an injection mold, and heat The manufacturing method of the electronic component mounting component which inject | pours the resin composition containing a plastic resin and a foaming agent and / or a foaming nucleating agent in the said injection mold.

  (5) Manufacture of electronic component mounting component according to (4), wherein holding pressure during injection molding is performed in multiple stages, holding pressure is 50 MPa or more at the time of filling, and then less than 50 MPa until the gate seal. Method.

  According to the present invention, a thermoplastic resin is used as a material for sealing an electronic component such as an IC. For this reason, the electronic component mounting component of this invention has high productivity compared with the case where a thermosetting resin is used.

  And as for the electronic component mounting component of this invention, the sealing resin part which seals an electronic component etc. is comprised from a foamed thermoplastic resin. By foaming, the force applied to the electronic component due to injection / holding pressure can be reduced, and by forming bubbles, it is possible to suppress the concentration of shrinkage stress on the electronic component due to shrinkage during solidification.

  Furthermore, as a result of at least a part of the outer peripheral shape of the cross section perpendicular to the base material of the sealing resin part being arcuate, the surface of the sealing resin part is difficult to deform due to solidification shrinkage for the arcuate part, The protective effect of electronic parts by foaming is not disturbed.

It is a figure which shows typically the electronic component mounting component of embodiment, (a) is a perspective view, (b) is sectional drawing. It is a figure which shows typically the sealing resin part in the electronic component mounting component of embodiment, (a) is a perspective view, (b) is sectional drawing. It is a schematic diagram for demonstrating a modification, (a) is sectional drawing for demonstrating a 1st modification, (b) is sectional drawing for demonstrating a 2nd modification.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment.

<Electronic component mounting parts>
Fig.1 (a) is a perspective view which shows typically the electronic component mounting component 1 of this embodiment, FIG.1 (b) is sectional drawing which shows typically AA cross section of Fig.1 (a). . The electronic component mounting component 1 according to this embodiment includes a substrate 10, an electronic component 11, and a sealing resin portion 12.

  As shown in FIG. 1A, in the electronic component mounting component 1 of the present embodiment, the sealing resin portion 12 seals the electronic component 11 in order to protect the electronic component 11 mounted on the substrate 10. Do it.

  As shown in FIG. 1, the substrate 10 is a member on which an electronic component 11 is mounted on one surface. The board 10 may have a wiring circuit for electrically connecting the electronic component 11 and other electronic components as necessary. The substrate 10 corresponds to the base material in the present invention.

  The material of the board | substrate 10 is not specifically limited, A conventionally well-known thing can be used. For example, a resin substrate composed of a silicon wafer, an epoxy resin, or the like can be exemplified. Moreover, the multilayer substrate etc. which consist of a some material may be sufficient.

  The shape of the substrate 10 is not particularly limited, and includes a shape other than the plate shape shown in FIG. Further, a flexible substrate such as a flexible substrate or a hard substrate such as a rigid substrate can be used.

  The electronic component 11 is a member that is mounted on one surface of the substrate 10. Specific examples of the electronic component 11 include a semiconductor chip having an elemental semiconductor such as silicone and germanium, a semiconductor chip having a compound semiconductor such as gallium-arsenic, indium-phosphorus, a resistor, a thermistor, and a capacitor.

  As will be described later, mechanical damage to the electronic component 12 can be sufficiently suppressed by using a specific thermoplastic resin. Therefore, the present invention can be suitably applied also when using electronic parts such as ferrite that are particularly vulnerable to mechanical damage.

  The electronic component 11 may have an electrode for electrical connection with a wiring circuit or the like on the substrate. Examples of the electrode include metals such as tin, copper, silver, and gold, alloys containing these metals, and materials such as solder.

  The sealing resin portion 12 is a member that covers the periphery of the electronic component 11 in order to protect the electronic component 11 mounted on the substrate 10. The present invention is characterized by the sealing resin portion 12. The characteristics are that the sealing resin portion 12 is made of a foamed thermoplastic resin and that the outer peripheral shape of the cross section perpendicular to the substrate of the sealing resin portion 12 is an arc shape.

  First, the foamed thermoplastic resin will be described. The foamed thermoplastic resin is a thermoplastic resin having a cell structure inside, and can be manufactured by kneading and molding a thermoplastic resin, a foaming agent, and a foam nucleating agent.

  Usable thermoplastic resins are not particularly limited, and conventionally known ones can be used. For example, polybutylene terephthalate resin, polyphenylene sulfide resin, liquid crystal resin and the like can be exemplified.

  As described above, in the present invention, any thermoplastic resin can be preferably used, but the use of polybutylene terephthalate resin is particularly preferable. As the polybutylene terephthalate resin, for example, the same resins as those described in JP-A 2010-150484 can be used.

  When polybutylene terephthalate resin is used, mechanical damage to the electronic component 11 and the substrate 10 can be suppressed, and thermal damage to the electronic component 11 and the substrate 10 can be suppressed by using a low melting point resin. it can. Moreover, even if the electronic component 11 is small by using a high fluidity thing, the electronic component 11 can be easily sealed.

  Use of polybutylene terephthalate resin is preferable because it provides the sealing resin portion 12 that has the required durability and can sufficiently suppress thermal and mechanical damage to the electronic component 11 and the substrate 10.

  The foamed thermoplastic resin can be added with other thermoplastic resins, various compounding agents, and the like as necessary within a range not impairing the effects of the present invention. Examples of other resins include other polyolefin resins, polystyrene resins, and fluororesins. These other resins may be used alone or in combination of two or more. In addition, as compounding agents, reinforcing agents such as glass fibers, stabilizers (antioxidants or antioxidants, ultraviolet absorbers, heat stabilizers, etc.), antistatic agents, flame retardants, flame retardant aids, colorants ( Dyes, pigments, etc.), lubricants, plasticizers, lubricants, mold release agents, crystal nucleating agents, anti-dripping agents, crosslinking agents and the like.

  As described above, a foaming nucleating agent or the like is used as the foaming agent in the production of the foamed thermoplastic resin.

  Examples of the foaming agent include volatile foaming agents used for physical foaming and degradable foaming agents used for chemical foaming. Examples of volatile blowing agents include inert or non-flammable gases (nitrogen, carbon dioxide, chlorofluorocarbon, alternative chlorofluorocarbon, etc.), water, organic physical blowing agents [for example, aliphatic hydrocarbons (propane, n-butane, isobutane). , Pentane (n-pentane, isopentane, etc.), hexane (n-hexane, etc.), aromatic hydrocarbon (toluene, etc.), halogenated hydrocarbon (trichlorofluoromethane, etc.), ethers (dimethyl ether, petroleum ether) Etc.), ketones (acetone etc.), etc.]. Examples of the decomposable foaming agent include inorganic carbonates such as sodium bicarbonate and ammonium carbonate or salts thereof; organic acids such as citric acid or salts thereof (sodium citrate, etc.); 2,2′-azobisiso Azo compounds such as butyronitrile and azodicarboxylic acid amide; sulfonyl hydrazide compounds such as benzenesulfonyl hydrazide; nitroso compounds such as N, N′-dinitrosopentamethylenetetramine (DNPT); azide compounds such as terephthalazide and the like . Of these foaming agents, aliphatic hydrocarbons such as butane and pentane, organic acids such as citric acid, or salts thereof (sodium citrate, etc.) are often used. These foaming agents may be used alone or in combination of two or more.

  The amount of foaming agent used is not particularly limited. It mix | blends with a thermoplastic resin in the ratio suitable for the foaming agent to be used.

  Examples of the foam nucleating agent include inorganic carbonates such as sodium bicarbonate and ammonium carbonate exemplified in the description of the foaming agent or salts thereof; organic acids such as citric acid or salts thereof (sodium citrate, etc.), and silicic acid. Examples thereof include compounds (talc, silica, zeolite, etc.), metal hydroxides (aluminum hydroxide, etc.), metal oxides (zinc oxide, titanium oxide, alumina, etc.) and the like. These foam nucleating agents may be used alone or in combination of two or more. Among the foam nucleating agents, in particular, when a silicate compound such as talc is used, the cell structure can be made uniform.

  The amount of the foam nucleating agent used is not particularly limited. It can mix | blend suitably as needed.

  The expansion ratio of the sealing resin portion 12 is not particularly limited. What is necessary is just to adjust a foaming ratio suitably in the range which does not reduce the quality of a product remarkably. The expansion ratio can be adjusted by components such as a thermoplastic resin, the type of foaming agent or foam nucleating agent, the amount of foaming agent or foaming nucleating agent added, the method of forming the sealing resin portion, and the like.

  The cell structure inside the sealing resin portion 12 is not particularly limited, and may be a closed cell structure or an open cell structure, or both cell structures may be mixed. It can change suitably according to a use. Control of the closed cell structure and the open cell structure can be performed by a conventionally known method.

  In the present invention, it is preferable to use thermally expandable microcapsules in which a foaming agent is enclosed in an outer shell because of the formation of closed cells. When the foaming volume increases and the bubbles continue, it becomes easy to form continuous voids, and an insulation failure or the like may occur due to moisture entering through the voids continuous from the surface of the molded body to the inside of the molded body. By using thermally expandable microcapsules that form closed cells, the formation of continuous voids can be avoided, making it difficult for such obstacles to occur.

  The outer shell of the thermally expandable microcapsule is made of a resin that is softened by heating and has low gas permeability. Examples of the resin include vinylidene chloride polymers, acrylonitrile polymers, acrylic polymers, and the like. These can be used individually by 1 type or in combination of 2 or more types. Among these, an acrylic polymer is preferable because it has a low environmental load. Examples of the acrylic polymer include homopolymers and copolymers such as polyacrylic acid, polymethacrylic acid, methyl acrylate, and ethyl acrylate, or copolymers with other compounds such as vinyl acetate. be able to.

  The foaming agent may be a substance having a boiling point equal to or lower than the softening point (generally 90 to 150 ° C.) of the resin constituting the outer shell.

  The heat-expandable microcapsule is prepared by subjecting the above foaming agent to a conventional method, for example, a method described in JP-B-42-26524 (mixing a polymerizable monomer with a foaming agent and a polymerization initiator, , If necessary, suspension polymerization in an aqueous medium containing an emulsifying and dispersing aid).

  Such thermally expandable microcapsules are, for example, as “Matsumoto Microsphere” from Matsumoto Yushi Seiyaku Co., Ltd., as “Advancel” from Sekisui Chemical Co., Ltd., as “Kureha Microsphere” from Kureha Corporation, or It is available from Akzo Nobel as “Expansel Microsphere”.

  Next, the shape of the sealing resin portion 12 will be described. As shown in FIG. 2A, the sealing resin portion 12 is in contact with a bottom surface 120 that is in contact with the substrate 10, a recess 121 that is in contact with the electronic component, and a component other than the components included in the electronic component mounting component 1, such as outside air. A surface 122.

  The bottom surface 120 is a surface in contact with the substrate 10, and more specifically, the bottom surface 120 is in contact with the surface on which the electronic component 11 of the substrate 10 is mounted.

  A cross section of the sealing resin portion 12 when the sealing resin portion 12 is cut along a plane perpendicular to the bottom surface 120 corresponds to a cross section of the sealing resin portion 12 perpendicular to the substrate 10. For example, a cross-sectional view (FIG. 2B) schematically representing the BB cross section of FIG. 2A is an example of a cross section perpendicular to the substrate 10 of the sealing resin portion 12.

  The outer peripheral shape of the surface 122 of the cross section perpendicular to the substrate 10 of the sealing resin portion 12 is a line connecting X1 and X2 in FIG. In the present invention, the line connecting X1 and X2 is arcuate. The entire line connecting X1 and X2 need not be arcuate, but 90% or more is preferably arcuate in the present invention.

  In the present embodiment, the entire outer peripheral shape of the surface 122 is a substantially perfect circular arc centered on the midpoint Xc between X1 and X2. A substantially perfect circle indicates that it may be an ellipse as long as it is substantially a perfect circle. A substantially perfect circle refers to an ellipse whose major axis has a length of about 0.8 to 1.2 times the length of the minor axis. An ellipse of this level is considered to have the same effect as a perfect circle. The allowable relationship between the length of the major axis and the length of the minor axis varies depending on the type of material, the application, and the like.

  In addition, although it is preferable that it is a substantially perfect circular arc shape, it may not be a substantially perfect circular arc shape. However, it is preferably as close to a perfect circle as possible, and the length of the major axis is preferably 0.5 to 2 times the length of the minor axis. Moreover, what connected the circular arc from which the position of a center, the magnitude | size of a radius, etc. differ is also contained in this invention.

  In addition, the “arc shape” is not a curved shape such as a cross section of a spherical shell, but is a circular shape even if it is not a curved shape, such as a cross section of a regular polyhedron (for example, a soccer ball composed of a regular pentagon and a regular hexagon). Including things like

  Further, as shown in FIG. 2A, the shape of the surface 122 of the present embodiment is a substantially spherical shape. The center of this substantially spherical surface is the center O of a circle that is a contact surface between the sealing resin portion 12 and the substrate 10. The “substantially true spherical surface” means that an elliptical spherical surface that has substantially the same effect as the true spherical surface is included in addition to the true spherical surface. “The elliptical spherical surface having substantially the same effect as a true spherical surface” means that the length of the longest radius is about 0.8 to 2 times the length of the shortest radius. Note that the above-described relationship between the length of the major axis and the length of the minor axis varies depending on the type and use of the material.

  In addition, 90% or more of the surface 122 is preferably a substantially spherical surface from the viewpoint of sufficiently obtaining the effects of the present invention. The surface 122 is preferably closer to a substantially spherical surface, but may have a shape other than a substantially spherical surface such as an elliptical spherical surface, and the length of the longest diameter is 0.5 times or more the length of the shortest diameter. It is preferable that it is 2 times or less. The shape of the surface 122 may be a shape in which spherical surfaces having different centers and radii are connected.

<Method of manufacturing electronic component mounting component>
The manufacturing method of the electronic component mounting component 1 of this embodiment is demonstrated. Although the manufacturing method of the electronic component mounting component of this invention is not specifically limited, For example, the following method can be illustrated.

  First, the electronic component 11 is mounted on the substrate 10. The method for mounting the electronic component 11 on the substrate 10 is not particularly limited, and a preferable method can be appropriately selected from general methods according to the type of the electronic component 11 and the like.

  Next, a sealing resin portion 12 for protecting the electronic component 11 is formed. The formation method of the sealing resin part 12 is not specifically limited. For example, the substrate 10 on which the electronic component 11 is mounted is mounted in a mold for injection molding, and sealing is performed by injecting a resin composition containing a thermoplastic resin and a foaming agent into the mold. The resin part 12 can be formed. This molding method corresponds to the injection sealing molding method.

  The timing of mixing the foaming agent, the foam nucleating agent and the thermoplastic resin is not particularly limited, and a raw material in which the thermoplastic resin and the foaming agent are mixed may be charged into the molding machine, and the resin being plasticized or kneaded A foaming agent or the like may be added to or pressed into. In addition, you may add the example additive, other resin, etc. in a suitable step if needed.

  Usually, the sealing resin part comprised from the foamed thermoplastic resin which has a cell structure inside can be formed by melt-kneading the said thermoplastic resin, a foaming agent, etc., and foam-molding.

  As the molding temperature, optimum conditions are appropriately set within a temperature range suitable for the thermoplastic resin and the foaming agent.

  It is desirable to perform multi-stage holding as the holding pressure at the time of molding. In general, by maintaining a constant holding pressure, the bubbles are formed to be almost uniform by the foaming pressure. However, in the present invention, when controlling the foaming form so that the shrinkage stress is not concentrated on the electronic component. In addition, the holding pressure cannot be controlled too low. If the holding pressure is too low, there is a concern about variations in product quality, particularly when many pieces are molded at once. By performing multistage pressure holding, when filling the mold cavity completely, it can be performed at a high pressure that suppresses foaming, and after the outer skin is formed, the shrinkage stress is applied to the electronic component at a low pressure. It is possible to form a highly foamed region that does not concentrate.

  When performing multistage holding pressure at the time of injection molding, it is preferable to set the holding pressure to 50 MPa or more at the time of filling, and then set the holding pressure to the gate seal to less than 50 MPa. The holding time is appropriately adjusted according to the size and shape of the sealing resin portion to be molded, the type of thermoplastic resin used as a raw material, and the like. The timing of switching from the condition in which the holding pressure is 50 MPa or more to the condition in which the holding pressure is less than 50 MPa is uniquely determined by determining each holding time.

<Effect>
Then, the effect of the electronic component mounting component of this embodiment is demonstrated. In the electronic component mounting component of the present embodiment, a part of the outer peripheral shape of the surface of the sealing resin portion in a cross section perpendicular to the substrate of the sealing resin portion is an arc shape. First, the effect of the outer peripheral shape of the surface being an arc will be described.
The foaming agent is foamed from the stage of filling the cavity with the foaming agent and the thermoplastic resin. By this foaming, the force applied to the electronic component at the stage of injecting the raw material at the time of filling can be reduced. Moreover, the force which a holding pressure gives to an electronic component at the time of holding pressure of injection molding can be reduced.
As described above, the sealing resin portion 12 is formed by injecting a molten resin composition into a mold. The formed sealing resin portion 12 gradually solidifies from the surface 122 and finally. Solidifies to the inside. The sealing resin portion 12 shrinks during the solidification process. However, if the arc shape is provided, the surface rigidity of the surface solidified in the initial stage becomes high, and deformation of the sealing resin portion 12 due to the shrinkage force during the cooling process is suppressed. be able to. As a result of suppressing the deformation, it is possible to suppress the bubble structure due to the foaming molding due to the shrinkage at the time of solidification and to suppress the concentration of the shrinkage stress on the electronic component 11.

  In this embodiment, the outer periphery shape of the surface 122 in the said cross section is a substantially perfect circular arc shape. If the arc shape is a substantially perfect circle, the rigidity of the surface solidified in the initial stage becomes very high. As a result, the possibility that the shrinkage stress is concentrated on the electronic component 11 is further reduced.

  In the present embodiment, the surface 122 is substantially spherical. First, if the surface 122 is a substantially spherical surface, the rigidity of the surface is increased as a whole, and the concentration of shrinkage stress on the electronic component 11 can be further suppressed.

  Furthermore, when the surface 122 is a substantially spherical surface, the distance from any position of the surface 122 to the center O of the substantially spherical surface is the same. Accordingly, the contraction force from the outer periphery of the surface 122 toward the center O of the sealing resin portion 12 is substantially the same from any position on the outer periphery. For this reason, it is difficult for a position where the contractile force acts locally to exist, and deformation is hardly caused from this point.

  If the foamable thermoplastic resin is a polybutylene terephthalate resin, thermal damage to the electronic component 11 during molding can be reduced.

  When an electronic component mounting component is manufactured by injection sealing molding, a spherical or arc-shaped sealing resin portion can be easily and accurately formed. Since the shape of these surfaces can be accurately manufactured, the desired electronic component mounting component can be manufactured stably by injection sealing molding.

<Modification>
As mentioned above, although each preferred embodiment of the channel formation structure of the present invention and its manufacturing method was described, the present invention is not restricted to the embodiment mentioned above but can be carried out in various forms.

  For example, in the above embodiment, the center O of the substantially true spherical surface and the center Xc of the arc-shaped arc exist on one surface of the substrate 10, but as shown in FIG. The center O of the spherical surface may be present above one surface of the substrate 10.

  Moreover, as shown in FIG.3 (b), the shape which two spheres united may be sufficient. In this case, only one of them may have a substantially spherical surface, but it is preferable that all have a substantially spherical surface as shown in FIG.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Material>
Thermoplastic resin: polybutylene terephthalate resin (hereinafter sometimes referred to as “low melting point PBT”) (manufactured by Wintech Polymer, Juranex 303RA, melting point: 182 ° C., MFR: 13 g / 10 min)
Foaming agent: Thermally expandable microcapsule (manufactured by Sekisui Chemical Co., Ltd., Advancel EMP501M1)

<Example 1>
A hoop terminal was set in a cavity having a cylindrical protruding pin on the back surface and a top surface of approximately 7 mm in diameter, and a material obtained by adding 3% by mass of a foaming agent to low melting point PBT was injection molded under the following conditions. . Thus, the electronic component mounting component of Example 1 was obtained.
(Molding condition)
Mold temperature: 60 ℃
Molding machine cylinder temperature: 260 ° C
Holding pressure: 10 seconds at 50 MPa

  When the external appearance of the electronic component mounting component of Example 1 was visually confirmed, no dent could be confirmed. From this, it was confirmed that the bubbles of the foamed thermoplastic resin were hardly destroyed at the time of solidification shrinkage of the thermoplastic resin during molding.

  When the electronic component mounting component was cut in the vertical direction and the cross section was observed, a large bubble group was observed in the central portion where the hoop terminal was provided. Therefore, when the material is filled in the cavity, it can be said that the force applied to the warp terminal at the time of holding pressure is suppressed by foaming.

  The confidentiality of the interface between the hoop terminal and the injection molded resin was judged by an ink penetration test. It was confirmed that there was almost no ink intrusion and there was no problem.

<Example 2>
The electronic component mounting component of Example 2 is the same as Example 1 except that the pressure holding condition is changed to a condition of holding pressure at 50 MPa for 3 seconds and then holding pressure at 10 MPa for 7 seconds. Manufactured.

  When the external appearance of the electronic component mounting component of Example 2 was visually confirmed, a dent could not be confirmed as in Example 1. When this electronic component mounting component was cut in the vertical direction and the cross section was observed, a very large bubble group was observed in the central portion where the hoop terminal was provided. The confidentiality of the interface between the hoop terminal and the foamed thermoplastic resin was judged by an ink penetration test. It was confirmed that there was almost no ink intrusion and there was no problem.

<Example 3>
The electronic component mounting component of Example 3 was manufactured in the same manner as in Example 1 except that the cavity was changed to an elliptical shape whose major axis was twice the minor axis. When the electronic component mounting component was cut in the longitudinal direction and the cross section was observed, bubbles were confirmed that could sufficiently relieve the contraction stress applied to the hoop terminal by the contraction when the foamed thermoplastic resin was solidified. The term “bubbles that can sufficiently relieve the shrinkage stress applied to the hoop terminal” means that the foamed thermoplastic resin has a foamed thermoplastic resin that contracts when the foamed thermoplastic resin is solidified, as compared with a spherical shape. Although the resin is easily deformed, it refers to a bubble that can sufficiently relieve the shrinkage stress and force applied to the internal electronic component even in consideration of the ease of deformation.

<Comparative Example 1>
An electronic component mounting component of Comparative Example 1 was manufactured in the same manner as in Example 1 except that no foaming agent was used. When the electronic component mounting component of Comparative Example 1 was cut in the vertical direction and the cross section was observed, a small cavity was observed in the central portion where the warp terminal was provided. However, this cavity is not sufficiently large with respect to the size of an electronic component such as a warp terminal, and the effect of relieving shrinkage stress and force applied to the electronic component cannot be sufficiently expected.

DESCRIPTION OF SYMBOLS 1 Electronic component mounting component 10 Board | substrate 11 Electronic component 12 Sealing resin part 120 Bottom 121 Recessed part 122 Surface

Claims (5)

A substrate;
An electronic component mounted on the substrate;
A sealing resin portion for sealing the electronic component,
The sealing resin portion is made of a foamed thermoplastic resin,
An electronic component mounting component in which the outer peripheral shape of the surface of the sealing resin portion in a cross section perpendicular to the base material of the sealing resin portion is an arc shape.   The electronic component mounting component according to claim 1, wherein the outer peripheral shape is a substantially circular arc.   The electronic component mounting component according to claim 1, wherein a surface of the sealing resin portion has a substantially spherical shape. A method for producing an electronic component mounting component according to any one of claims 1 to 3,
An electronic component in which an electronic component mounted on a substrate is fixed in an injection mold and a resin composition containing a thermoplastic resin and a foaming agent and / or a foaming nucleating agent is injected into the injection mold. Manufacturing method of mounted components.   5. The method of manufacturing an electronic component mounting component according to claim 4, wherein the holding pressure at the time of injection molding is performed in multiple stages, is 50 MPa or more at the time of filling, and is less than 50 MPa until the gate seal thereafter.

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