JP2019054288A - Electronic component of hollow structure - Google Patents

Abstract

To provide an electronic component of a hollow structure having a chip connected to a substrate by bumps, which can be applied to a chip large in heat radiation amount, and which is sealed by a highly heat conducting resin sheet, provided that the resin sheet enables the achievement of both of no resin incursion to under the chip, and the flatness of a resin on the chip.SOLUTION: An electronic component of a hollow structure has a chip connected to a substrate by bumps. The electronic component is arranged by sealing the chip by a resin sheet having a thermal conductivity of 4 W/m K or more at a room temperature with a space between the chip and the substrate kept hollow. The resin sheet is a gelatinous epoxy resin sheet arranged by blending a hardening resin with a thermoplastic resin, blending the hardening resin with an optical radical polymer, or blending the hardening resin with an optical radical polymerizable compound and a photoradical generating agent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hollow structure electronic component in which a chip connected to a substrate by a bump is sealed with a thermally conductive resin sheet, and the space between the chip and the wiring substrate is kept hollow. The present invention relates to a hollow structure electronic component formed by sealing with a highly heat conductive resin sheet that can be applied to many electronic component chips.

  In recent years, electronic components in which chips such as functional elements are sealed on a wiring board via bumps and kept between the chip and the wiring board are used in various electronic devices such as mobile phones. Has been. Typical examples of such a device include a surface acoustic wave (SAW) device, a crystal resonator, and a piezoelectric resonator. In such electronic components, the active surface of the chip must be prevented from being sealed with resin. For example, in a SAW device, a SAW electrode is formed on a SAW chip, and a resin seal is formed on a wiring board. Since the performance cannot be exhibited if the sealing resin or the substrate surface and the SAW electrode come into contact with each other, the resin must be sealed with the electrode surface kept hollow. On the other hand, such electronic components have been miniaturized, and the manufacture of such electronic components is also performed on a substrate in a so-called MAP (mold array package) in which a large number of small chips, for example, SAW chips, are arranged by flip chip bonding. A method in which a large number of chips are encapsulated with resin at once has become the mainstream.

  In recent years, duplexers having a transmission / reception function are increasing as an extension technique of SAW. Since the duplexer has a higher operating current value than the SAW device, heat generation of the chip becomes a problem. In general, heat dissipation of a chip in an electronic component is performed through bumps. However, in a chip having a small number of bumps such as a SAW device or a duplexer, it is difficult to sufficiently dissipate heat via the bumps. Therefore, a hollow structure electronic component that can dissipate heat with high efficiency through a heat dissipation path other than the bump is desired.

  Conventionally, as a resin sealing technique of a hollow structure electronic component, for example, a technique of sealing with a gel-like curable resin sheet (for example, see Patent Documents 1 and 2) is known. However, an epoxy resin or the like used as a curable resin has a large thermal resistance and insufficient heat dissipation, and cannot be used as a heat dissipation path.

JP 2006-19714 A JP 2003-17979 A

  The present invention is an electronic component having a chip that is connected to a substrate by a bump, and can be applied to a chip with a large amount of heat dissipation. There is no resin intrusion under the chip, and the flatness of the resin on the chip is compatible. It aims at providing the hollow structure electronic component formed by sealing with the highly heat conductive resin sheet which can be performed.

  The present invention is an electronic component having a chip connected to a substrate by a bump, and the chip is held with a resin sheet having a thermal conductivity of 4 W / m · K or more at room temperature, and the space between the chip and the substrate is kept hollow. In this case, the resin sheet is formed by mixing a thermoplastic resin with a curable resin, a photo radical polymer with a curable resin, or curing. A hollow structure electronic component that is a gel-like epoxy resin sheet, in which a photo-radical polymerizable compound and a photo-radical generator are blended with a functional resin (however, an electronic component having a chip connected to a substrate by a bump at room temperature) A hollow structure electronic component in which a chip is sealed with a resin sheet having a thermal conductivity of 4 W / m · K or more, and the chip and the substrate are kept hollow, and the resin sheet is a curable resin In A gel-like epoxy resin formed by blending a plastic resin, blending a photoradical polymer with a curable resin, or blending a photoradical polymerizable compound and a photoradical generator with a curable resin. A hollow structure electronic component that is a sheet, which is sealed with a plurality of laminated resin sheets, includes at least two resin sheets having different thermal conductivities, and has at least two different thermal conductivities Among the resin sheets, the resin sheet in contact with the chip has a higher thermal conductivity than that of the other resin sheets (except for hollow electronic components).

With the above-described configuration, the hollow structure electronic component of the present invention radiates heat from the chip to the substrate through the high thermal conductive resin sheet as a heat dissipation path other than the bump, and radiates heat from the substrate to the motherboard through the wiring, or from the chip to high thermal conductivity A heat dissipation path that dissipates heat to the upper surface of the electronic component via the resin sheet can be realized, and can be applied to an element with a large amount of heat dissipation. Moreover, in the hollow structure electronic component of the present invention, the sealing resin sheet does not penetrate the resin under the chip and can be satisfactorily sealed with a hollow, and the flatness of the resin on the chip can be compatible. Can also be implemented.
Therefore, the hollow structure electronic component of the present invention can be suitably applied to the manufacture of a duplexer or the like.

The schematic cross section which shows the example of the sealing structure of the hollow structure electronic component of this invention. The schematic cross section which shows the other example of the sealing structure of the hollow structure electronic component of this invention.

  In the present invention, as the thermally conductive resin sheet, a resin sheet made of a resin having adhesiveness to a substrate, a chip or the like is used as long as it has a thermal conductivity of 4 W / m · K or more at room temperature. can do. When the sheet has anisotropic thermal conductivity (for example, when the thermal conductivity is different between the sheet spreading direction and the thickness direction), the largest thermal conductivity is 4 W / m · K or more. I just need it. If the thermal conductivity is less than 4 W / m · K, the heat generated from the chip cannot be sufficiently radiated through the thermally conductive resin sheet, which is disadvantageous because the operation performance of the chip deteriorates. Preferably, it is 5 W / m · K or more. As a method for measuring the thermal conductivity, the xenon flash method is desirable because the difference from the actual thermal conductivity can be easily reduced. If the measurement temperature has temperature dependence, a value at room temperature, for example, 25 ° C. is used. Specifically, the heat conductivity can be achieved by containing a heat conductive filler.

  As the heat conductive resin sheet, for example, a curable resin sheet, for example, a gel curable resin sheet formed by blending a thermoplastic resin with a thermosetting resin is preferable. As the heat conductive resin sheet, a gel-like curable resin sheet formed by using a mixture of a thermosetting resin, a photo radical polymerizable compound, and a photo radical generator is also preferable. In this case, before carrying out thermosetting of the heat conductive resin sheet, it is irradiated with light to carry out photo radical polymerization of the photo radical polymerizable compound. Further, as the gel-like curable resin sheet, a mixture of a photoradical polymer obtained by photoradical polymerization in advance and a thermosetting resin can also be preferably used. The gel-like curable resin sheet is in the form of a gel in a range from a softening point (a temperature at which the viscosity decreases and deforms due to external pressure) to a curing temperature. Specifically, in this specification, a curing temperature, for example, 40 In the dynamic viscoelasticity measurement at a temperature of 0 ° C. or higher, tan δ is 1 or lower. When tan δ is 1 or less, since a viscoelastic solid state is exhibited during curing and heating, resin penetration under the chip can be suppressed, and hollow sealing can be performed with high accuracy. On the other hand, if tan δ is greater than 1, it will not flow in the viscoelastic solid state because it flows during heating. In order to make tan δ be 1 or less, a thermoplastic resin may be usually blended with the thermosetting resin by the method described later.

  Specific examples of the curable resin include, for example, epoxy resins, phenoxy resins, phenol resins, unsaturated polyester resins, alkyd resins, urethane resins, melamine resins, urea resins, guanamine resins, polyimide resins, polyamide resins, vinyl ester resins. , Diallyl phthalate resin, xylene resin, silicon resin and the like, and two or more kinds may be used in combination. Among these, epoxy resin has low viscosity and can be highly filled with filler, ensuring adhesion to substrates and chips, improving reliability and heat dissipation, and by combining with various thermoplastic resin powders Desirable in adjusting rheological properties. The curable resin generally uses a known curing agent and / or curing accelerator and other additives.

  Hereinafter, an epoxy resin will be described as an example, but those skilled in the art can appropriately select other known curable resins as well. Specific examples of the epoxy resin include, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, hydrogenated bisphenol A type epoxy resin, phenol novolac type epoxy resin, and alicyclic aliphatic epoxy resin. Glycidyl ethers of organic carboxylic acids, biphenyl type epoxy resins, amino epoxy resins, prepolymers of the above epoxy resins, polyether modified epoxy resins, silicone modified epoxy resins, and the like. As the epoxy resin, two or more of these may be used in combination. Among these, bisphenol A type epoxy resin and bisphenol F type epoxy resin are desirable from the viewpoints of economy and adhesiveness. The number average molecular weight of the epoxy resin can be 100 to 200,000.

  As the epoxy resin curing agent, those conventionally used can be used, and specific examples thereof include, for example, phenol curing agents, dicyandiamide curing agents, urea curing agents, organic acid hydrazide curing agents, Examples include polyamine salt-based curing agents and amine adduct-based curing agents. These may be used alone or in combination of two or more. Of these, phenol-based curing agents are preferred from the standpoints of low outgassing properties during curing, moisture resistance, heat cycle resistance, and the like. A dicyandiamide curing agent, a urea curing agent, an organic acid hydrazide curing agent, a polyamine salt curing agent, and an amine adduct curing agent are latent curing agents, and are preferable from the viewpoint of storage stability.

  The latent curing agent preferably has an activation temperature of 60 ° C. or higher, more preferably 80 ° C. or higher. The upper limit of the active temperature is preferably 250 ° C. or lower, and more preferably 180 ° C. or lower from the viewpoint of being able to improve productivity at high temperature or higher and fast curability.

  The amount used when the epoxy resin curing agent is used varies depending on the type of the curing agent, and thus cannot be specified unconditionally. Usually, the number of functional group equivalents of the curing agent is 0.5 per equivalent of epoxy group. -1.5 equivalents, more preferably 0.7-1.2 equivalents, particularly preferably 0.8-1.1 equivalents.

  As the curing accelerator, those conventionally used in epoxy resin compositions can be used. From the viewpoint of storage stability, latent curing acceleration with an active temperature of 60 ° C. or higher, further 80 ° C. or higher is possible. Agents are preferred. The upper limit of the activation temperature is preferably 250 ° C. or less, and more preferably 180 ° C. or less from the viewpoint of high curing acceleration at the activation temperature or more and improvement in productivity.

  Specific examples of the latent curing accelerator include a modified imidazole curing accelerator, a modified aliphatic polyamine accelerator, a modified polyamine accelerator, and the like. These may be used alone or in combination of two or more. Of these, modified imidazole-based curing accelerators are preferable from the viewpoints of high activity temperature, good reactivity, and high purity.

  The amount used in the case of using the latent curing accelerator varies depending on the type of the latent curing accelerator and cannot be defined unconditionally, but is usually 1 to 80 parts by weight per 100 parts by weight of the epoxy resin. Is preferably 5 to 50 parts by weight.

  As the thermoplastic resin, those that melt or soften by heating, or those that dissolve in the solvent when using a solvent can be used, and as the shape, powder, pellets, plate, lump, etc. can be used, Preferably, a powdered thermoplastic resin is used. Examples of the thermoplastic resin include polyvinyl chloride, polyethylene, polypropylene, polystyrene, synthetic rubber (polybutadiene, butadiene-styrene copolymer, polyisoprene, polychloroprene, ethylene-propylene copolymer), polyvinyl acetate, poly ( Examples thereof include (meth) acrylic acid ester, polyacrylic acid amide, polyoxymethylene, polyphenylene oxide, polyester, polyamide, polycarbonate resin, polyacrylonitrile, thermoplastic polyimide, polyvinyl alcohol, and polyvinylpyrrolidone. These may be used alone or in combination of two or more. Of these, polymethacrylates such as polymethylmethacrylate are preferred from the viewpoint of sheeting.

  The softening temperature, molecular weight, etc. of the thermoplastic resin cannot be generally defined, but generally, from the point of reactivity of the sheet forming temperature and the curable resin such as epoxy resin used, the softening temperature is It is preferable that it is 50-150 degreeC, and it is preferable that a number average molecular weight is 3 million or less, Furthermore, it is preferable that it is 1 million or less.

  The average particle diameter of the thermoplastic resin powder is preferably 0.01 to 200 μm, more preferably 0.01 to 100 μm in terms of primary particle diameter from the viewpoint of controlling the thickness of the sheet. The average particle diameter is a number-based average particle diameter measured by a particle size distribution measuring apparatus based on a laser diffraction / scattering method.

  Examples of the thermally conductive filler include crystalline silica, boron nitride, silicon nitride, aluminum nitride, alumina, magnesium oxide, zinc oxide, diamond, carbon, carbon nanotube, metal filler (copper, silver, etc.), and the like. The shape is usually particulate (spherical, ellipsoidal shape with an aspect ratio of 1 to less than 2, geometric shape, irregular shape, etc.), with an aspect ratio of 2 or more, for example 50 or less, preferably 30 to 50. Fiber shape, plate shape, and the like. Two or more kinds of the fillers may be used. Of these, alumina and boron nitride are desirable from the viewpoint of moisture resistance and high thermal conductivity, and aluminum nitride is desirable from the viewpoint of high thermal conductivity. Since aluminum nitride does not have sufficient moisture resistance, it is desirable to use a surface-treated one. For example, an aluminum nitride layer and an organic compound layer having an insulating property can be used.

  In order to develop the anisotropic thermal conductivity of the sheet, a filler having an anisotropic thermal conductivity can be used. Specifically, the sheet has an anisotropic thermal conductivity depending on the arrangement of atoms and the like. Examples thereof include a filler and a filler having a high aspect ratio (specifically, a filler having an aspect ratio of 3 or more, more preferably 5, more preferably 8 or more). In the case of a filler having a high aspect ratio, the shape is preferably a fiber shape or a plate shape. In the present specification, the shape of needles, cylinders, and the like is included in the fiber shape, and the shape of the flakes and the like is included in the plate shape. More preferably, a fibrous carbon nanotube or a plate-like boron nitride is desirable. For example, if boron nitride is a plate-like (in this case, a piece-like shape), 30% or more of the total filler is used. It is possible to have different thermal conductivities in different thermal conduction directions, and for example, it is possible to develop a thermal conductivity anisotropy of 1.5 times or more. The filler can be surface-treated with a coupling agent or the like in order to maintain interfacial adhesion with the resin and improve reliability and thermal conductivity.

  For example, in the case of alumina, the amount of the thermally conductive filler is generally 70 to 95% by weight in the resin composition, and in the case of boron nitride, it is generally 45 to 75% by weight in the resin composition. In the case of aluminum nitride, it is generally 70 to 90% by weight in the resin composition. When the blending amount of the thermally conductive filler is less than the above range, it is difficult to ensure a thermal conductivity of 4 W / m · K or more. On the other hand, when it exceeds the above range, the smoothness of the protective film and adhesion to the substrate are difficult. May be impaired. In view of high thermal conductivity and adhesion to the substrate, the alumina is more preferably 75 to 93% by weight, and more preferably 80 to 90% by weight. Further, boron nitride is more preferably 55 to 70% by weight, and aluminum nitride is more preferably 75 to 93% by weight.

  The gel-like curable resin sheet is, for example, a liquid or solid curable composition (that is, a composition comprising a curable resin, a curing agent, a curing accelerator, and the like; the same applies hereinafter) and heat acting as a gelling agent. It can be manufactured by forming a mixture with a plastic resin into a sheet. The gelling agent is a curable resin (for example, epoxy resin) that is a main component of the resin sheet, which can be gelled as a whole resin composition while being in an A-stage shape without reaction. Note that the gelling agent for the solid curable composition is intended to enable gelation even when heated and softened.

  The ratio of the liquid or solid curable composition and the thermoplastic resin used in the production of the gel curable resin sheet varies depending on the type of the curable composition used and the type of the thermoplastic resin. In general, it is preferably 5 to 100 parts by weight, more preferably 10 to 70 parts by weight with respect to 100 parts by weight of the epoxy resin. If the amount of the thermoplastic resin is too small, the sheet strength tends to decrease when the sheet is formed, and if it is too large, the fluidity is low, high pressure is required during heat pressing, and chip breakage is likely to occur. .

  Mix and hold a liquid or solid curable composition and a thermoplastic resin as described above, and absorb the curable composition into the thermoplastic resin, or make the curable composition and the thermoplastic resin compatible. Thus, a gel-like curable composition can be obtained.

  In order to promote absorption of the curable composition into the thermoplastic resin or compatibility between the curable composition and the thermoplastic resin, heating is preferably performed. At this time, it is preferable that the curable composition is applied by, for example, a roll coater and then heated for gelation. The heating temperature in this case is not less than the glass transition temperature of the thermoplastic resin, preferably not less than the softening temperature, less than the melting start temperature of the thermoplastic resin, less than the activation temperature of the curing agent used and / or the latent curing accelerator. Preferably it is temperature. Usually, the temperature is preferably 5 to 50 ° C., more preferably 10 to 30 ° C. higher than the softening temperature of the thermoplastic resin, and the temperature is equal to or lower than the active temperature of the curing agent and / or latent curing accelerator used. preferable. The heating time may be sufficient as long as the curable composition is absorbed into the thermoplastic resin or the curable composition and the thermoplastic resin are compatible with each other to obtain a gelled curable composition. The heating temperature is usually 60 to 150 ° C., more preferably 80 to 120 ° C., and the heating time is 0.5 to 30 minutes, further 1 to 10 minutes. (The SAW chip can be protected with a sealing layer formed from a gel-like curable resin sheet by a heat press performed thereafter).

  When the resin sheet is formed by these methods, since it is solventless, for example, a resin sheet having a thickness of about 50 μm to a thick resin sheet of 1000 μm can be manufactured. If a solvent-based material is used, only a material having a thickness of about 100 μm can be produced.

  In the above description, as the gel-like curable resin sheet, a sheet of a mixture of a liquid or solid curable composition and a thermoplastic resin acting as a gelling agent is used. Form a sheet using a mixture of a curable composition and a photo radical polymer that acts as a gelling agent, or a mixture of a liquid or solid curable composition, a photo radical polymerizable compound and a photo radical generator. You may use what you did. In this case, first, a mixture of a liquid or solid curable composition, a photo-radical polymerizable compound and a photo-radical generator is prepared and irradiated with light to polymerize the photo-radical polymerizable compound. Is used as a gel-like curable sheet.

  Examples of the photo-radically polymerizable compound include one or more (meth) acryloyl group-containing compounds in the molecule, such as esters of (meth) acrylic acid with alkyl alcohols, alkylene diols, polyhydric alcohols, and the like. Examples thereof include compounds described in [0009] to [0012] of Kaihei 11-12543.

  Examples of the photo radical generator include compounds that generate radicals upon irradiation with actinic rays such as ultraviolet rays and electron beams, and various conventionally used ones such as 2-hydroxy-2 -Methyl-1-phenylpropan-1-one, benzoin, acetophenone, etc. can be used.

  The amount of the photo radical generator used is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, per 100 parts by weight of the photo radical polymerizable compound.

  As the use ratio of the liquid or solid curable composition and the photo radical polymer or photo radical polymerizable compound and photo radical generator, the photo radical polymer or the light is used per 100 parts by weight of the curable composition. The total of the radical polymerizable compound and the photo radical generator is preferably 5 to 100 parts by weight, more preferably 10 to 30 parts by weight.

  The thickness of the gel-like curable resin sheet used in the present invention formed using the photo radical polymer or the photo radical polymerizable compound and the photo radical generator was formed using the thermoplastic resin. It may be the same as the thickness of the gel-like curable resin sheet.

  In the present invention, the photo-radically polymerizable compound and the photo-radical generator are preliminarily polymerized to prepare a photopolymer, and a mixture obtained by mixing this with a liquid or individual curable composition is converted into a gel curable composition. It can also be used as a sheet. In this case, light irradiation after preparation of the mixture is unnecessary.

  The resin sheet is prepared by coating using a roll coater / printer, etc., in solvent-based materials, by drying the solvent by heating, and in solvent-free systems, by heating and swelling the thermoplastic resin with the epoxy resin. can do.

  In the present invention, the orientation of the thermally conductive filler can be enhanced by using an external force such as a magnetic field, an electric field, and stress. Specifically, when forming a composition containing a high-aspect-ratio thermally conductive filler such as a fiber shape, a plate shape, etc., a process such as coating, using a shearing force at the time of extrusion, rolling, stretching, etc. By passing, the orientation can be given to the filler, and the anisotropy of the thermal conductivity of the sheet can be increased. More specifically, in the case of coating, the rheological properties at the time of coating are adjusted by the fluidity and solvent concentration of the anisotropic thermally conductive filler, and the fiber shape, using the shearing force from the coating head, The orientation of the thermally conductive filler having a high aspect ratio such as a plate shape can be increased, and the anisotropy of the thermal conductivity can be increased.

The gel-like curable resin sheet thus obtained is usually suitable for forming a protective layer such as a SAW chip having a thickness of about 50 to 1000 μm and a thickness of about 250 μm by a heat sealing method. In addition, since it has a low glass transition temperature and a low linear expansion coefficient, it is possible to reduce the stress of the cured product (low warpage), and when the raw material is highly purified Further, there are few impurity ions, and contamination of the chip surface can be prevented. Furthermore, the elastic modulus (25 ° C.) of the gel-like curable resin sheet is 10 ³ to 10 ⁹ Pa, and further 10 ⁴ to 10 ^8. Since the melt viscosity at curing is 10 to 10 ⁵ Pa · s, and further 10 ³ to 10 ⁴ Pa · s, the SAW electrode surface and the wiring are formed on the device before the sealing layer is formed by heat pressing. Pa Can be a surface that over emissions are formed to form the sealing layer so that the height sentence spaced portions of the bumps to form a hollow sealing portion.

  When the gel-like curable resin sheet has anisotropic thermal conductivity, it is desirable to dispose the sheet so that the thermal conductivity increases in the direction in which it is desired to dissipate heat. For example, if it is desired to efficiently dissipate heat to the substrate, a sealing layer may be formed using a resin sheet having high thermal conductivity in the sheet spreading direction, and if it is desired to efficiently dissipate heat on the upper surface, The sealing layer may be formed using a resin sheet with high thermal conductivity.

  The thickness of the gel-like curable resin sheet is such that a sealing layer can be formed by covering the chip connected with the bump on the substrate on which the wiring pattern is formed, and performing heat pressing. Since the surface of the layer can be made substantially flat, the thickness of the sealing layer is not less than the thickness of the chip + the height of the bump and not more than twice the thickness of the chip + the height of the bump. Furthermore, it is preferable to adjust the thickness of the gel-like curable resin sheet so that it is 1.5 times or less of the thickness of the chip + the height of the bump. Specifically, for example, when the chip thickness is 200 to 400 μm and the bump height is 20 to 80 μm, the sealing layer thickness is preferably 220 to 960 μm, and more preferably 220 to 720 μm. At this time, in order to reliably spread the softened resin sheet to the chip hem and form a hollow sealing part, the volume to be filled in the sealing part is calculated, and the gel-like curable property is calculated based on this volume. It is desirable to set the resin sheet thickness.

  As a sealing method, a general method such as a vacuum press or a vacuum laminate can be used, and any method conforming thereto can be used.

  The hollow structure electronic component of the present invention is manufactured using the gel-like curable resin sheet. At this time, it is effective for removing bubbles that the gel-like curable resin sheet is temporarily attached to the device before forming the sealing layer under vacuum. Bubbles can also be removed by performing heat pressing under vacuum.

  The heat press is generally performed at a pressure of 100 Pa to 10 MPa, further 0.01 to 2 MPa, a temperature of 250 ° C. or less, more preferably 60 to 180 ° C., particularly 150 ° C., 5 seconds to 3 hours, and further 1 to 15 minutes. , Especially 5 minutes.

  According to the present invention, “sealing and sealing” means that a resin sheet is used, and the portion where the internal electrode surface of the chip and the surface on which the wiring pattern is formed is separated by the height of the bump is a hollow structure It is possible to secure a path for radiating the heat generated by the chip to the substrate by connecting the chip and the substrate using a resin sheet having high thermal conductivity.

  An embodiment of the present invention will be specifically illustrated and described. In a MAP-shaped substrate in which a chip is flip-chip bonded to a substrate, as shown in FIG. By covering with a heat conductive resin sheet, it can be sealed so as to maintain a hollow structure. Note that the entire top surface and side surfaces of the chip do not have to be covered with the heat conductive resin sheet, and a part thereof may be exposed. For example, as shown in FIG. 2 (2), when a plurality of chips are sealed in a hollow state, a structure in which a part of the side surface of the chip is not covered with a heat conductive resin sheet can be taken (the chip of the chip). Depending on the arrangement, there may be a structure in which only the upper surface is covered with the heat conductive resin sheet and the entire side surface is exposed. Further, as shown in FIG. 2 (3), a heat conductive resin sheet covers the chip side surface and the substrate, forms a hollow structure and is sealed, and the chip upper surface is exposed. This can be created, for example, by performing hollow sealing in the mode of (1) in FIG. 1 and then polishing the surface to expose the upper surface of the chip. Alternatively, for example, a sealing film having a thickness of the chip and a height of the bump may be formed by heat pressing so that the upper surface of the chip and the upper surface of the sealing film are continuously flat. Further, in the embodiment of (3) in FIG. 2, a heat conductive layer described later can be formed so as to cover the exposed chip upper surface, the surface of the heat conductive resin sheet, and the bonding interface thereof.

  In the hollow structure electronic component of the present invention, it may be sealed with one sheet of the heat conductive resin sheet, or may be sealed with a plurality of stacked layers of the heat conductive resin sheet. The plurality of resin sheets may be sealed using those laminated in advance, or may be sequentially sealed and laminated one by one. Further, the laminated structure may be continuously formed as in the embodiment of (4) in FIG. 2, or the laminated structure is formed intermittently as in the embodiment of (5) in FIG. May be.

  The plurality of laminated resin sheets preferably include at least two resin sheets having different thermal conductivities. For example, two sheets having different thermal conductivity, or three or more sheets having two types of thermal conductivity, three sheets having three types of thermal conductivity, or three types of thermal conductivity There may be four or more sheets having Increasing the amount of thermally conductive filler to increase thermal conductivity makes it difficult to ensure flatness on the chip, so use a sheet with less amount of thermally conductive filler on the surface of the sealing film. In addition, the flatness on the chip can be secured, and the high thermal conductivity of the sheet in contact with the chip can be secured. In this case, for example, among the plurality of laminated resin sheets, the thermal conductivity of the resin sheet in contact with the chip is higher than the thermal conductivity of the other laminated resin sheets, for example, at least 5 W / m · It can be made to have a thermal conductivity of K.

  In addition, at least one of the laminated resin sheets has a thermal conductivity in the sheet spreading direction rather than a thermal conductivity in the thickness direction (that is, a thermal conductivity in a direction perpendicular to the thickness direction. Also, when there is anisotropy in conductivity (for example, when the thermal conductivity is different in the sheet longitudinal direction and width direction), the largest thermal conductivity is 1.5 times or more, preferably 1.5. It can be made to have a high thermal conductivity (referred to herein as “anisotropic thermal conductivity”) of ˜5 times, more preferably 2 to 4 times. In this case, the thermal conductivity in the thickness direction can be 2 W / m · K or more. And at least the resin sheet in contact with the chip has the above anisotropic thermal conductivity, so that the heat dissipation of the chip is efficiently conducted in the spreading direction of the resin sheet rather than in the thickness direction of the resin sheet. Thus, heat can be efficiently radiated from the resin sheet to the substrate.

  Moreover, as a preferable aspect of the hollow structure electronic component of the present invention, the resin sheet forms a hollow sealing portion so as to cover the side surface of the chip and the substrate, and at least a part of the upper surface of the chip is the resin sheet. Further, a thermal conductive layer having a thermal conductivity of 5 W / m · K or more is formed so as to cover the exposed chip upper surface and the bonding interface between the resin sheet and the chip. It will be. The thermal conductivity of the thermal conductive layer may be either isotropic or anisotropic. In this case, the heat conductive layer may be made of the above heat conductive resin sheet, or may be made of a metal thin film or a graphite sheet.

  As a method for producing a preferred embodiment of the hollow structure electronic component of the present invention, a chip connected to a substrate by a bump is a resin sheet having a thermal conductivity of 4 W / m · K or more at room temperature, and the chip and the substrate are After covering and hollow-sealing while keeping the space hollow, the coating resin on the chip is polished, and a thermal conductive layer having a thermal conductivity of 5 W / m · K or more is formed on the flattened surface. And a method for producing a hollow structure electronic component characterized by the following: In this case, the coating resin on the chip is polished until at least a part of the upper surface of the chip is exposed, so that a heat conductive layer is formed on the surface so that heat can be released from the chip to the upper surface through the heat conductive layer. Increased efficiency.

  In the present invention, the chip is not particularly limited as long as it has bumps and constitutes an electronic component, and examples thereof include an electronic chip, a SAW chip, a duplexer element, a crystal oscillator, and a MEMS.

  Specific examples of the hollow structure electronic component of the present invention include devices, modules, and the like on which the above chip or the like is mounted or used as a component.

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

Example 1, Example 2, Comparative Example 1
Each component was mixed with the following mixing | blending (weight part) with the biaxial mixer, and the compositions 1-3 for curable resin sheets were obtained, respectively. Blackening was performed with carbon black to improve the temperature measurement accuracy of the thermo viewer. In addition, when the dynamic viscoelasticity measurement was performed about the composition for curable resin sheets, tan (delta) (40 degreeC) is 0.80 in Example 1, 0.79 in Example 2, 0.64 in Comparative Example 1. Met.

Example 1
Composition 1 for curable resin sheet
Formulated bisphenol A type epoxy resin (epoxy equivalent 180) 100 parts by weight Phenol novolak (hydroxyl equivalent 141) 55 parts by weight Polymethyl methacrylate (powder: average particle size 1 μm) 20 parts by weight Alumina (spherical: average particle size 12 μm) 1500 parts by weight 1 part by weight of curing accelerator (imidazole) 1 part by weight of carbon black

Example 2
Curable resin sheet composition 2
Compound bisphenol A type epoxy resin (epoxy equivalent 180) 100 parts by weight phenol novolak (hydroxyl equivalent 141) 55 parts by weight polymethyl methacrylate (powder: average particle size 1 μm) 20 parts by weight boron nitride (rhombus plate: aspect ratio 11) 260 1 part by weight curing accelerator (imidazole) 1 part by weight carbon black 1 part by weight

Comparative Example 1
Curable resin sheet composition 3
Compound bisphenol A type epoxy resin (epoxy equivalent 180) 100 parts by weight phenol novolak (hydroxyl equivalent 141) 55 parts by weight polymethyl methacrylate (powder: average particle size 1 μm) 20 parts by weight fused silica (spherical: average particle size 8 μm) 1500 weights Part hardening accelerator (imidazole) 1 part carbon black 1 part by weight

A test chip (TEG chip for heat generation measurement) is flip-chip bonded to a ceramic substrate (bump + chip thickness is 450 μm), and each curable resin sheet composition is applied to a thickness of 500 μm with a roll coater to form a sheet. The resin sheet thus obtained was heat-pressed under the conditions of 0.1 MPa, 120 ° C., and 5 minutes to obtain a hollow structure electronic component having a sealing layer having a thickness of 550 μm (a thickness from the substrate to the upper surface of the sealing film). The surface temperature of the obtained electronic component was measured. The measurement method is as follows.
The TEG chip for heat generation measurement was energized so that the chip heat generation was about 80 ° C. on the surface of the reference electronic component, and using this as a reference, the temperature of the electronic component of the example was measured from the surface using a thermo viewer. The temperature difference with respect to the reference is shown in Table 1.

Moreover, the thermal conductivity of the resin sheet obtained by forming each curable resin sheet composition into a thickness of 500 μm using a roll coater was measured at room temperature (25 ° C.). The measurement method is as follows. The results are shown in Table 1.
Measurement Method After laminating the sheets and pressing at 150 ° C. for 10 minutes, the sheet was post-cured at 150 ° C. for 3 hours and polished to prepare a 10 mm square 1 mm thick test piece. As a measuring device, LFA447 Nano Flash (registered trademark) manufactured by NETZSCH was used. (Ramp voltage 270V, pulse width 0.18ms)

  From these results, in the example, the surface temperature is lower than that of the electronic component of the comparative example, and the heat generated by the operation of the chip is transmitted from the surface of the electronic component or the substrate through the heat conductive sheet arranged in contact with the chip. It has been demonstrated that a lot of heat can be dissipated. As a result, it was shown that the electronic component of the present invention has high heat dissipation efficiency.

a: Thermally conductive resin sheet b: Chip c: Hollow part d: Bump e: Substrate f: Thermally conductive layer

Claims (13)

  An electronic component having a chip that is connected to a substrate by a bump, and is sealed with a resin sheet having a thermal conductivity of 4 W / m · K or more at room temperature, and the space between the chip and the substrate is kept hollow. The resin sheet is formed by blending a thermoplastic resin with a curable resin, a radical photopolymer compounded with a curable resin, or light with a curable resin. Hollow structure electronic component, which is a gel-like epoxy resin sheet containing a radical polymerizable compound and a photoradical generator (however, an electronic component having a chip connected to a substrate by a bump, which is 4 W / m · at room temperature) A hollow structure electronic component in which a chip is sealed with a resin sheet having a thermal conductivity equal to or higher than K and the space between the chip and the substrate is kept hollow, and the resin sheet is formed of thermoplastic resin on a curable resin. A gel-like epoxy resin sheet formed by blending a photoradical polymer with a curable resin, or by blending a photoradical polymerizable compound and a photoradical generator with a curable resin. A hollow structure electronic component, which is sealed with a plurality of laminated resin sheets, includes at least two resin sheets having different thermal conductivity, and includes at least two sheets having different thermal conductivity Among the resin sheets, a hollow structure electronic component in which the thermal conductivity of the resin sheet in contact with the chip is higher than the thermal conductivity of the other resin sheets is excluded).   The hollow structure electronic component according to claim 1, wherein the resin sheet contains a thermally conductive filler.   The hollow structure electronic component according to claim 2, wherein the thermally conductive filler is at least one selected from the group consisting of boron nitride, aluminum nitride, and aluminum oxide.   The thermal conductive filler is a thermal conductive filler having anisotropic thermal conductivity, and the resin sheet has different thermal conductivity in the sheet thickness direction and the sheet spreading direction. The hollow structure electronic component as described.   The hollow structure electronic component according to claim 4, wherein the thermally conductive filler having anisotropic thermal conductivity is a fibrous or plate-like thermally conductive filler having an aspect ratio of 3 or more.   The hollow structure electronic component according to any one of claims 1 to 5, wherein the hollow structure electronic component is sealed with a plurality of laminated resin sheets.   The hollow structure electronic component according to claim 6, comprising at least two resin sheets having different thermal conductivities.   At least one of the plurality of laminated resin sheets has an anisotropic thermal conductivity in which the thermal conductivity in the sheet spreading direction is 1.5 times or more higher than the thermal conductivity in the thickness direction. Item 8. The hollow structure electronic component according to Item 6 or 7.   The hollow structure electronic component according to claim 8, wherein at least the resin sheet in contact with the chip has anisotropic thermal conductivity. The resin sheet is provided so that the side surface of the chip and the substrate are covered to form a hollow sealing portion, and at least a part of the upper surface of the chip is exposed from the resin sheet. The hollow structure electronic component according to claim 1, wherein a heat conductive layer having a heat conductivity of 5 W / m · K or more is formed so as to cover the upper surface and the bonding interface between the resin sheet and the chip.   The hollow structure electronic component according to claim 10, wherein the heat conductive layer is made of a heat conductive resin sheet.   The hollow structure electronic component according to claim 10, wherein the heat conductive layer is made of a metal thin film.   The hollow structure electronic component according to claim 10, wherein the heat conductive layer is made of a graphite sheet.

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