JP2016204545A - Encapsulation resin sheet and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encapsulation resin sheet having sufficient heat radiation performance, capable of appropriately encapsulating an electronic device.SOLUTION: An encapsulation resin sheet includes an inorganic filler. The inorganic filler includes alumina particles. The content of the alumina particles is 50 vol.% or more with regard to the entire inorganic filler. The maximum grain size of the alumina particles is within a range of 10 μm or more and 50 μm or less. The heat conductivity in a sheet thickness direction is 3 W/m.K or more after thermal cure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sealing resin sheet and an electronic device device.

  Conventionally, in the production of an electronic device device (for example, an electronic component device or a semiconductor device), typically, one or a plurality of electronic devices (for example, an electronic component or a semiconductor chip) fixed to a substrate or the like via a bump or the like. Is sealed with a sealing resin, and a procedure of dicing the sealing body into a package of an electronic device unit as necessary is employed. As such a sealing resin, a sheet-shaped sealing resin may be used (for example, refer to Patent Document 1).

  Examples of the method for manufacturing the electronic device apparatus include a method in which one or a plurality of electronic devices arranged on an adherend are embedded in a sealing resin sheet, and then the sealing resin sheet is thermally cured.

  On the other hand, in recent years, as the speed of data processing of electronic device devices has increased, the amount of heat generated from electronic devices has increased, and the importance of designing electronic device devices having heat dissipation has increased. The heat has various adverse effects not only on the electronic device apparatus itself but also on the electronic equipment body in which it is incorporated.

JP 2006-19714 A

  Thus, in recent years, there has been a demand for the development of a sealing resin sheet that can suitably seal an electronic device and has sufficient heat dissipation.

  This invention is made | formed in view of the said problem, The objective is to provide the resin sheet for sealing which can seal an electronic device suitably and has sufficient heat dissipation. is there.

  The inventors of the present application have found that the above-mentioned problems can be solved by adopting the following configuration, and have completed the present invention.

That is, the sealing resin sheet according to the present invention is
Containing inorganic fillers,
The inorganic filler includes alumina particles,
The content of the alumina particles is 50% by volume or more with respect to the whole inorganic filler,
The maximum particle size of the alumina particles is in the range of 10 μm or more and 50 μm or less,
The thermal conductivity in the sheet thickness direction after thermosetting is 3 W / m · K or more.

Alumina has a relatively high thermal conductivity. According to the said structure, the inorganic filler is included, the said inorganic filler contains an alumina particle, and the content of the said alumina particle is 50 volume% or more with respect to the said whole inorganic filler. Since the alumina particles are contained in an amount of 50% by volume or more based on the entire inorganic filler, the heat dissipation of the resin sheet for sealing after thermosetting can be enhanced.
Moreover, since the maximum particle diameter of the alumina particles is 10 μm or more, the viscosity of the sealing resin sheet can be set to a low viscosity suitable for embedding an electronic device. Moreover, since the maximum particle diameter of the said alumina particle is 50 micrometers or less, when an electronic device is sealed, it can prevent that an alumina particle is exposed from the resin sheet for sealing on an electronic device. Moreover, when sealing the some electronic device arrange | positioned on a board | substrate, it can prevent that an alumina particle is pinched | interposed between electronic devices.
Moreover, since the thermal conductivity in the sheet thickness direction after thermosetting is 3 W / m · K or more, the heat dissipation is excellent.
Thus, according to the sealing resin sheet of the present invention, the electronic device can be suitably sealed, and a sealing resin sheet having high heat dissipation can be provided.

  In the above configuration, the inorganic filler may further contain boron nitride. In that case, the content of the boron nitride is preferably 5% by volume or more with respect to the whole inorganic filler.

  Boron nitride has higher thermal conductivity than alumina. Therefore, if boron nitride is contained in an amount of 5% by volume or more based on the entire inorganic filler, a sealing resin sheet having higher heat dissipation can be provided.

  The said structure WHEREIN: It is preferable that the heat conductivity of the sheet thickness direction after thermosetting is 5 W / m * K or more.

  When the thermal conductivity in the sheet thickness direction after thermosetting is 5 W / m · K or more, a sealing resin sheet having higher heat dissipation can be provided.

  The said structure WHEREIN: It is preferable that the surface of the said alumina particle is hydrophobized with the silane coupling agent.

  When the surface of the alumina particles is hydrophobized with a silane coupling agent, wettability with the resin component in the sealing resin sheet is improved. As a result, the viscosity before thermosetting can be lowered.

  Moreover, this invention is an electronic device apparatus which has the said resin sheet for sealing.

  According to the said structure, since it has the said resin sheet for sealing, the said electronic device apparatus is excellent in heat dissipation.

It is sectional drawing which shows typically the resin sheet for sealing which concerns on one Embodiment of this invention. It is a figure which shows typically 1 process of the manufacturing method of the electronic device apparatus which concerns on one Embodiment of this invention. It is a figure which shows typically 1 process of the manufacturing method of the electronic device apparatus which concerns on one Embodiment of this invention. It is a figure which shows typically 1 process of the manufacturing method of the electronic device apparatus which concerns on one Embodiment of this invention. It is a figure which shows typically 1 process of the manufacturing method of the electronic device apparatus which concerns on one Embodiment of this invention. It is a figure which shows typically 1 process of the manufacturing method of the electronic device apparatus which concerns on one Embodiment of this invention.

  The present invention will be described in detail below with reference to embodiments, but the present invention is not limited only to these embodiments.

  [Resin sheet for sealing]

  FIG. 1 is a cross-sectional view schematically showing a sealing resin sheet (hereinafter also simply referred to as “resin sheet”) according to an embodiment of the present invention. The resin sheet 11 is typically provided in a state of being laminated on a separator 11a such as a polyethylene terephthalate (PET) film. The separator 11a may be subjected to a mold release process in order to easily peel the resin sheet 11.

The resin sheet 11 has a thermal conductivity after thermosetting of 3 W / m · K or more, preferably 4 W / m · K or more, and more preferably 5 W / m · K or more. Since the thermal conductivity after thermosetting is 3 W / m · K or more, the thermal conductivity is excellent. The method of setting the thermal conductivity after thermosetting to 3 W / m · K or more can be achieved by adding a specific amount of an inorganic filler having a specific particle size, as will be described later.
In the present invention, “thermal conductivity after thermosetting” refers to thermal conductivity after heating at 150 ° C. for 30 minutes under normal pressure.

  The sealing sheet 11 preferably has a viscosity at 90 ° C. before thermosetting of 5 to 2000 kPa · s, more preferably 10 to 1500 kPa · s, and 50 to 1000 kPa. -More preferably within the range of s. The viscosity at 90 ° C. assumes the viscosity at the time of electronic device sealing. When the viscosity at 90 ° C. of the sealing resin sheet 11 is within the above numerical range, the electronic device can be suitably embedded in the sealing resin sheet 11 and sealed.

  The resin sheet 11 contains an inorganic filler.

  The inorganic filler includes alumina particles.

  The content of the alumina particles is 50% by volume or more, preferably 60% by volume or more, and more preferably 70% by volume or more with respect to the entire inorganic filler. Alumina has a relatively high thermal conductivity. Since the resin sheet 11 contains 50% by volume or more of alumina particles with respect to the entire inorganic filler, the heat dissipation of the resin sheet 11 after thermosetting can be improved.

  In the resin sheet 11, as a method for determining whether or not the alumina particles are contained in an amount of 50% by volume or more based on the whole inorganic filler, a cross section of a cured product of the resin sheet 11 is simply observed with an SEM image, There is a method of calculating from the area of alumina particles in the total. Of course, the cured product may be subjected to chemical analysis such as ICP emission spectroscopic analysis or fluorescent X-ray analysis to determine whether the alumina particles contain 50% by volume or more based on the entire inorganic filler.

  The maximum particle size of the alumina particles is in the range of 10 μm to 50 μm, preferably in the range of 13 μm to 40 μm, and more preferably in the range of 15 μm to 30 μm. Since the maximum particle size of the alumina particles is 10 μm or more, the viscosity of the resin sheet 11 (viscosity before thermosetting) can be set to a low viscosity suitable for embedding an electronic device. In addition, since the maximum particle size of the alumina particles is 50 μm or less, it is possible to prevent the alumina particles from being exposed from the resin sheet 11 on the electronic device when the electronic device is sealed to produce an ultra-thin package. it can. Moreover, when sealing the some electronic device arrange | positioned on a board | substrate, it can prevent that an alumina particle is pinched | interposed between electronic devices.

  The average particle diameter of the alumina particles is preferably 2 μm or more and 10 μm or less, and more preferably 3 μm or more and 6 μm or less. When the average particle size is 2 μm or more, the viscosity of the resin sheet 11 (viscosity before thermosetting) can be set to a low viscosity suitable for embedding an electronic device. On the other hand, when the average particle size is 10 μm or less, wear of the dicing blade can be suppressed when the plurality of electronic device packages are separated by dicing after curing.

  The surface of the alumina particles is preferably hydrophobized with a silane coupling agent. When the surface of the alumina particles is hydrophobized with a silane coupling agent, wettability with the resin component in the resin sheet 11 is improved. As a result, the viscosity before thermosetting can be lowered.

  The silane coupling agent is not particularly limited as long as the surface of the alumina particles can be hydrophobized, and examples thereof include those having a methacryloxy group, an acryloxy group, an epoxy group, and an amino group. Specific examples of the silane coupling agent include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryloxy. Examples include octyltrimethoxysilane, methacryloxyoctyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, N-phenyl-3-amipropyltrimethoxysilane, and the like. Of these, 3-methacryloxypropyltrimethoxysilane is preferable from the viewpoints of reactivity and low viscosity.

  The alumina particles are preferably surface-treated in advance with 0.5 to 2 parts by weight of the silane coupling agent with respect to 100 parts by weight of the alumina particles.

  If the surface treatment of the alumina particles is performed with a silane coupling agent, the viscosity of the sealing sheet 11 (viscosity before thermosetting) can be reduced. However, if the amount of the silane coupling agent is large, the outgas generation amount increases. To do. Therefore, even if the alumina particles are surface-treated in advance, the performance of the sealing sheet 11 deteriorates due to the outgas generated when the sealing sheet 11 is formed. On the other hand, when there is little quantity of a silane coupling agent, a viscosity cannot be reduced suitably. Therefore, if the alumina particles are surface-treated in advance with 0.5 to 2 parts by weight of a silane coupling agent with respect to 100 parts by weight of the alumina particles, the viscosity can be suitably reduced and performance degradation due to outgassing is suppressed. be able to.

The inorganic filler may further contain boron nitride in addition to alumina. This is because boron nitride has higher thermal conductivity than alumina. When boron nitride is included, hexagonal boron nitride is preferable.
When the resin sheet 11 contains boron nitride (hexagonal boron nitride or tetragonal boron nitride) as an inorganic filler, the shape thereof is not limited, and may be scaly, agglomerating scaly boron nitride. Secondary aggregates may be used. However, hexagonal boron nitride has a scaly general crystal structure, and its thermal conductivity in the a-axis direction (plane direction) is several times the thermal conductivity in the c-axis direction (thickness direction). The thermal anisotropy is several tens of times. Therefore, it is preferable to use as a secondary aggregate aggregated so as to have isotropic properties.

  Here, from the viewpoint of thermal conductivity alone, alumina particles are not used as the inorganic filler, or even if used, the content is reduced, and the secondary aggregate of hexagonal boron nitride is mainly used. It seems to be good. However, when the hexagonal boron nitride secondary aggregate is contained in the resin sheet, the resin is difficult to enter into the voids in the secondary aggregate, so that the sheet becomes hard and brittle and increases in viscosity. Therefore, it is difficult to use as a sealing resin sheet. Therefore, in this embodiment, alumina particles are mainly used as the inorganic filler to suppress a decrease in followability, and in order to further improve heat dissipation, boron nitride may be included in addition to the alumina particles. It has a good structure.

The applicant has filed a separate application regarding a sealing resin sheet mainly using a secondary aggregate of boron nitride as an inorganic filler. In this application, after embedding the electronic device in the sealing resin sheet, while maintaining the pressurized state, the sealing resin sheet is heated and subjected to primary thermosetting, thereby improving thermal conductivity and the like. Secured.
On the other hand, in this embodiment, the sealing resin that can be used without adopting a special process of curing the sealing resin sheet (primary thermosetting) while maintaining a pressurized state. A sheet is provided. In other words, the sealing resin sheet according to the present embodiment has a thermal conductivity if a simple process of thermosetting without applying pressure (under normal pressure) is performed after sealing the electronic device. It is possible to increase the height. Moreover, the viscosity at the time of embedding is made suitable.

  The boron nitride content is preferably 5% by volume or more, more preferably 10% by volume or more, and still more preferably 30% by volume or more with respect to the entire inorganic filler. Further, from the viewpoint of followability and cost, the boron nitride content is preferably 50% by volume or less, and more preferably 40% by volume or less with respect to the entire inorganic filler. If hexagonal boron nitride is contained in an amount of 5% by volume or more based on the entire inorganic filler, a sealing resin sheet having a lower viscosity and higher heat dissipation can be provided. Specifically, the thermal conductivity in the sheet thickness direction after thermosetting is easily set to 3 W / m · K or more, and more preferably 5 W / m · K or more.

  The average particle size of the secondary aggregate is preferably 5 μm or more and 200 μm or less, more preferably 10 μm or more and 150 μm or less. By setting the average particle size of the secondary aggregate to 5 μm or more, thermal conductivity can be suitably imparted. On the other hand, when the average particle size of the secondary aggregate is 200 μm or less, it is easy to reduce the thickness of an electronic device device manufactured using the resin sheet 11.

  The maximum particle size of the secondary aggregate is preferably 250 μm or less, and more preferably 200 μm or less. By making the maximum particle size of the secondary aggregates 250 μm or less, the electronic device device can be made thinner.

  The shape of the secondary aggregate is not limited to a spherical shape, and may be another shape. However, when manufacturing the resin sheet 11, considering that the blending amount of the secondary aggregates can be increased while ensuring the fluidity of the thermosetting resin, the secondary aggregated particles are nearly spherical. Is preferred. In addition, when the secondary aggregate has a shape other than a spherical shape, the average particle diameter means the length of the long side in the shape.

  The secondary aggregate can be produced according to a known method using a predetermined boron nitride crystal. Specifically, a predetermined boron nitride crystal is fired and crushed, or the predetermined boron nitride crystal is aggregated by a known method such as spray drying and then fired and sintered (grain growth). . Here, the firing temperature is not particularly limited, but is generally 2,000 ° C.

  Known secondary aggregates can be used. Specific products include “PT” series (for example, “PTX60”, etc.) manufactured by Momentive Performance Materials Japan GK, and “HP series” (for example, “HP” manufactured by Mizushima Alloy Iron Co., Ltd.). -40 ", etc.), and" Shubi NU UHP "series (for example," Shubi NU UHP-EX ") manufactured by Showa Denko KK can be mentioned.

The inorganic filler may contain fillers other than the alumina particles and the boron nitride. The other filler is preferably one having thermal conductivity to some extent, or one capable of imparting a function other than thermal conductivity to the resin sheet 11. For example, metal nitride such as aluminum nitride, silicon nitride, gallium nitride; for example, metal oxide such as silicon dioxide (silica), magnesium oxide, titanium oxide, zinc oxide, tin oxide, copper oxide, nickel oxide; Hydroxides such as aluminum oxide, boehmite, magnesium hydroxide, calcium hydroxide, zinc hydroxide, silicic acid, iron hydroxide, copper hydroxide, barium hydroxide; for example, zirconium oxide hydrate, tin oxide hydrate, Examples include hydrated metal oxides such as basic magnesium carbonate, hydrotalcite, dowsonite, borax, and zinc borate; silicon carbide, calcium carbonate, barium titanate, potassium titanate, and the like. Among these, silica, particularly fused silica is preferable. Fused silica has a low linear expansion integer (0.5 × 10 ⁻⁶ / K) and is close to a semiconductor material. Therefore, if fused silica is used as another filler, the warp of the electronic device device can be further suppressed.

  In the present specification, the average particle size and the maximum particle size of the inorganic filler refer to values obtained by measurement using a laser diffraction type particle size distribution analyzer.

  The total content of the inorganic filler is preferably 50% by volume to 90% by volume and more preferably 70% by volume to 85% by volume with respect to the entire resin sheet 11.

  The resin sheet 11 preferably includes a thermosetting resin and a thermoplastic resin.

  As said thermosetting resin, an epoxy resin and a phenol resin are preferable. Thereby, favorable thermosetting is obtained.

  The epoxy resin is not particularly limited. For example, triphenylmethane type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, modified bisphenol A type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, modified bisphenol F type epoxy resin, dicyclopentadiene type Various epoxy resins such as an epoxy resin, a phenol novolac type epoxy resin, and a phenoxy resin can be used. These epoxy resins may be used alone or in combination of two or more.

  From the viewpoint of ensuring the reactivity of the epoxy resin, it is preferable that the epoxy equivalent is 150 to 250, and the softening point or the melting point is 50 to 130 ° C., which is solid at room temperature. Of these, triphenylmethane type epoxy resin, cresol novolac type epoxy resin, and biphenyl type epoxy resin are more preferable from the viewpoint of reliability. Further, bisphenol F type epoxy resin is preferable because flexibility can be imparted to the thermosetting resin sheet 11.

  The phenol resin is not particularly limited as long as it causes a curing reaction with the epoxy resin. For example, a phenol novolac resin, a phenol aralkyl resin, a biphenyl aralkyl resin, a dicyclopentadiene type phenol resin, a cresol novolak resin, a resole resin, or the like is used. These phenolic resins may be used alone or in combination of two or more.

  As the phenol resin, it is preferable to use a phenol resin having a hydroxyl group equivalent of 70 to 250 and a softening point of 50 to 110 ° C. from the viewpoint of reactivity with the epoxy resin. From the viewpoint of high curing reactivity, a phenol novolac resin can be suitably used. From the viewpoint of reliability, low hygroscopic materials such as phenol aralkyl resins and biphenyl aralkyl resins can also be suitably used.

  From the viewpoint of curing reactivity, the blending ratio of the epoxy resin and the phenol resin is blended so that the total number of hydroxyl groups in the phenol resin is 0.7 to 1.5 equivalents with respect to 1 equivalent of the epoxy group in the epoxy resin. Preferably, it is 0.9 to 1.2 equivalents.

  The content of the thermosetting resin in 100% by weight of all components other than the filler is preferably 70% by weight or more, more preferably 75% by weight or more, and further preferably 80% by weight or more. CTE1 of hardened | cured material can be made small as it is 70 weight% or more. On the other hand, the content of the thermosetting resin is preferably 95% by weight or less, more preferably 92% by weight or less, still more preferably 90% by weight or less, and particularly preferably 88% by weight or less.

  It is preferable that the resin sheet 11 contains a hardening accelerator.

  The curing accelerator is not particularly limited as long as it cures the epoxy resin and the phenol resin. For example, 2-methylimidazole (trade name; 2MZ), 2-undecylimidazole (trade name; C11). -Z), 2-heptadecylimidazole (trade name; C17Z), 1,2-dimethylimidazole (trade name; 1.2 DMZ), 2-ethyl-4-methylimidazole (trade name; 2E4MZ), 2-phenylimidazole (Trade name; 2PZ), 2-phenyl-4-methylimidazole (trade name; 2P4MZ), 1-benzyl-2-methylimidazole (trade name; 1B2MZ), 1-benzyl-2-phenylimidazole (trade name; 1B2PZ) ), 1-cyanoethyl-2-methylimidazole (trade name; 2MZ-CN), 1-cyano Tyl-2-undecylimidazole (trade name; C11Z-CN), 1-cyanoethyl-2-phenylimidazolium trimellitate (trade name; 2PZCNS-PW), 2,4-diamino-6- [2'-methyl Imidazolyl- (1 ′)]-ethyl-s-triazine (trade name; 2MZ-A), 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine ( Trade name: C11Z-A), 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine (trade name; 2E4MZ-A), 2, 4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine isocyanuric acid adduct (trade name; 2MA-OK), 2-phenyl-4,5-dihydroxyme Examples include imidazole-based curing accelerators such as ruimidazole (trade name; 2PHZ-PW) and 2-phenyl-4-methyl-5-hydroxymethylimidazole (trade name; 2P4MHZ-PW). )).

  Of these, 2-phenyl-4,5-dihydroxymethylimidazole is preferable. Since 2-phenyl-4,5-dihydroxymethylimidazole promotes curing at a high temperature, it can be suppressed from being cured by heat in the embedding process.

  The content of the curing accelerator is preferably 0.2 parts by weight or more, more preferably 0.5 parts by weight or more, further preferably 0.8 parts by weight or more with respect to 100 parts by weight of the total of the epoxy resin and the phenol resin. It is. The content of the curing accelerator is preferably 5 parts by weight or less, more preferably 2 parts by weight or less with respect to 100 parts by weight of the total of the epoxy resin and the phenol resin.

  The resin sheet 11 preferably contains a thermoplastic resin. Thereby, the heat resistance of the sealing resin sheet obtained, flexibility, and intensity | strength can be improved. The thermoplastic resin is preferably one that can function as an elastomer.

  Examples of the thermoplastic resin include acrylic elastomers, urethane elastomers, silicone lastmers, and polyester elastomers. Of these, acrylic elastomers are preferred from the viewpoints of obtaining flexibility and good dispersibility with the epoxy resin.

  The acrylic elastomer is not particularly limited, and one or two or more esters of acrylic acid or methacrylic acid having a linear or branched alkyl group having 30 or less carbon atoms, particularly 4 to 18 carbon atoms. The polymer (acrylic copolymer) etc. which use as a component is mentioned. Examples of the alkyl group include a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, t-butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, heptyl group, cyclohexyl group, 2- Examples include an ethylhexyl group, an octyl group, an isooctyl group, a nonyl group, an isononyl group, a decyl group, an isodecyl group, an undecyl group, a lauryl group, a tridecyl group, a tetradecyl group, a stearyl group, an octadecyl group, and a dodecyl group.

  In addition, the other monomer forming the polymer is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Carboxyl group-containing monomers such as acid anhydride monomers such as maleic anhydride or itaconic anhydride, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4- (meth) acrylic acid 4- Hydroxybutyl, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate or (4-hydroxymethylcyclohexyl) -Methyla Hydroxyl group-containing monomers such as relate, styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate or (meth) Examples thereof include sulfonic acid group-containing monomers such as acryloyloxynaphthalene sulfonic acid, and phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate. Especially, it is preferable to include at least one of a carboxyl group-containing monomer, a glycidyl group (epoxy group) -containing monomer, and a hydroxyl group-containing monomer from the viewpoint of increasing the viscosity of the resin sheet 11 by reacting with the epoxy resin.

  The thermoplastic resin may have a functional group. As the functional group, a carboxyl group, an epoxy group, a hydroxyl group, an amino group, and a mercapto group are preferable, and a carboxyl group is more preferable.

The weight average molecular weight of the thermoplastic resin is preferably 500,000 or more, more preferably 800,000 or more. On the other hand, the weight average molecular weight of the thermoplastic resin is preferably 2 million or less, more preferably 1.5 million or less. When the weight average molecular weight is within the above numerical range, the viscosity is appropriate, and handling during blending is easy.
The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

  The content of the thermoplastic resin in 100% by weight of all components other than the filler is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 11% by weight or more, and still more preferably 12% by weight or more. is there. The softness | flexibility and flexibility of a resin sheet are acquired as it is 5 weight% or more. On the other hand, the content of the thermoplastic resin is preferably 30% by weight or less, more preferably 20% by weight or less. If it is 30% by weight or less, the storage elastic modulus of the resin sheet 11 does not become too high, and both embedding and flow regulation can be achieved.

  The resin sheet 11 may include a flame retardant component as necessary. This can reduce the expansion of combustion when ignition occurs due to component short-circuiting or heat generation. As the flame retardant composition, for example, various metal hydroxides such as aluminum hydroxide, magnesium hydroxide, iron hydroxide, calcium hydroxide, tin hydroxide, complex metal hydroxides; phosphazene flame retardants, etc. should be used. Can do.

  The resin sheet 11 may contain a silane coupling agent. It does not specifically limit as a silane coupling agent, 3-Glycidoxypropyl trimethoxysilane etc. are mentioned.

  The content of the silane coupling agent in the resin sheet 11 is preferably 0.1 to 3% by weight. When it is 0.1% by weight or more, the hardness of the cured resin sheet can be increased and the water absorption rate can be reduced. On the other hand, generation | occurrence | production of outgas can be suppressed as the said content is 3 weight% or less.

  The resin sheet 11 preferably contains a pigment. The pigment is not particularly limited, and examples thereof include carbon black.

  The content of the pigment in the resin sheet 11 is preferably 0.1 to 2% by weight. When the content is 0.1% by weight or more, good marking properties can be obtained. The intensity | strength of the resin sheet after hardening can be ensured as it is 2 weight% or less.

  In addition to the above components, other additives can be appropriately blended in the resin composition as necessary.

[Method for producing sealing resin sheet]
The resin sheet 11 is prepared by dissolving and dispersing a resin or the like for forming the resin sheet 11 in an appropriate solvent to adjust the varnish, and coating the varnish on the separator 11a to a predetermined thickness to form a coating film. Then, the coating film can be formed by drying under predetermined conditions. In addition, it is good also as the resin sheet 11 of desired thickness by laminating | stacking a some resin sheet as needed, and heat-pressing (for example, 60 second at 90 degreeC). It does not specifically limit as a coating method, For example, roll coating, screen coating, gravure coating, etc. are mentioned. As drying conditions, for example, the drying temperature is 70 to 160 ° C. and the drying time is 1 to 30 minutes. Moreover, after apply | coating a varnish on a separator and forming a coating film, the coating film may be dried on the said drying conditions, and the resin sheet 11 may be formed. Then, the resin sheet 11 is bonded together with the separator on the separator 11a. In particular, when the resin sheet 11 contains a thermoplastic resin (acrylic resin), an epoxy resin, and a phenol resin, all of them are dissolved in a solvent, and then applied and dried. Examples of the solvent include methyl ethyl ketone, ethyl acetate, toluene and the like.

  Although the thickness of the resin sheet 11 is not specifically limited, For example, it is 100-2000 micrometers, More preferably, it is 110-1800 micrometers. An electronic device can be favorably sealed as it is in the said range.

  The resin sheet 11 may have a single layer structure or a multilayer structure in which two or more resin sheets having different compositions are laminated, but there is no risk of delamination, and the sheet thickness is highly uniform, A single-layer structure is preferable because it easily reduces moisture absorption.

  The resin sheet 11 includes a SAW (Surface Acoustic Wave) filter; a MEMS (Micro Electro Mechanical Systems) such as a pressure sensor and a vibration sensor; a semiconductor such as an IC such as an LSI, a transistor, and a semiconductor chip; a capacitor; a resistor; an electron such as a CMOS sensor. Used for device sealing. Especially, it can use suitably for sealing of the electronic device (specifically SAW filter, MEMS) which needs hollow sealing, and can use it especially especially especially for sealing of a SAW filter.

[Method of manufacturing hollow package]
FIG. 2A to FIG. 2E are views schematically showing one step of the method for manufacturing the electronic device device according to one embodiment of the present invention.
In the present embodiment, a case where the electronic device device is a hollow package will be described. Specifically, a case where a SAW chip 13 mounted on the printed wiring board 12 is hollow sealed with a resin sheet 11 to manufacture a hollow package will be described. However, the present invention is not limited to this example, and a similar method can be adopted for manufacturing an electronic device device having no hollow portion.

(SAW chip mounting substrate preparation process)
In the method for manufacturing a hollow package according to the present embodiment, first, as shown in FIG. 2A, a laminate 15 in which a plurality of SAW chips 13 are mounted on a printed wiring board 12 is prepared (step A).
The SAW chip 13 corresponds to the electronic device of the present invention. The printed wiring board 12 corresponds to the support body of the present invention.
The SAW chip 13 can be formed by dicing a piezoelectric crystal on which predetermined comb-shaped electrodes are formed by a known method. For mounting the SAW chip 13 on the printed wiring board 12, a known device such as a flip chip bonder or a die bonder can be used. The SAW chip 13 and the printed wiring board 12 are electrically connected via protruding electrodes 13a such as bumps. In addition, a hollow portion 14 is maintained between the SAW chip 13 and the printed wiring board 12 so as not to inhibit the propagation of surface acoustic waves on the surface of the SAW filter. The distance (width of the hollow portion) between the SAW chip 13 and the printed wiring board 12 can be set as appropriate, and is generally about 10 to 100 μm.

(Resin sheet preparation process)
Moreover, in the manufacturing method of the hollow package which concerns on this embodiment, the resin sheet 11 is prepared (process B). As described above, the resin sheet 11 contains specific alumina particles and the like.

(Resin sheet placement process)
Next, as shown in FIG. 2B, the laminate 15 is disposed on the lower heating plate 41 with the surface on which the SAW chip 13 is mounted facing upward, and the resin sheet 11 is disposed on the surface of the SAW chip 13. (Process C). In this step, the laminated body 15 may be first arranged on the lower heating plate 41, and then the resin sheet 11 may be arranged on the laminated body 15, and the resin sheet 11 is laminated on the laminated body 15 first. Thereafter, a laminate in which the laminate 15 and the resin sheet 11 are laminated may be disposed on the lower heating plate 41. The separator 11a is preferably not peeled off at this stage.

(Embedding process)
Next, as shown in FIG. 2C, the SAW chip 13 is sealed with the resin sheet 11 by hot pressing with the lower heating plate 41 and the upper heating plate 42 (step D). The embedding process refers to a process from the start of embedding of the SAW chip 13 until the entire SAW chip 13 is embedded.

The hot press conditions for sealing the SAW chip 13 with the resin sheet 11 are preferably such that the SAW chip 13 can be suitably embedded in the resin sheet 11, and the temperature is, for example, 40 to 150 ° C. Preferably it is 60-120 degreeC, and a pressure is 0.1-10 Mpa, for example, Preferably it is 0.5-8 Mpa.
In addition, in consideration of improvement in adhesion and followability of the resin sheet 11 to the SAW chip 13 and the printed wiring board 12, it is preferable to press under reduced pressure conditions. As said pressure reduction conditions, it is 0.1-5 kPa, for example, More preferably, it is 0.1-100 Pa.

(Thermosetting process)
Next, the separator 11a is peeled off, and the resin sheet 11 is heat-cured (see FIG. 2D). The conditions for the thermosetting treatment can be appropriately set according to the constituent material of the resin sheet 11. For example, the heating temperature is preferably 100 ° C. or higher, more preferably 120 ° C. or higher. On the other hand, the upper limit of the heating temperature is preferably 200 ° C. or lower, more preferably 180 ° C. or lower. The heating time is preferably 10 minutes or more, more preferably 30 minutes or more. On the other hand, the upper limit of the heating time is preferably 180 minutes or less, more preferably 120 minutes or less. Further, the resin sheet 11 according to the present embodiment is assumed to be used by being thermoset in a non-pressurized state (normal pressure), but may be pressurized as necessary, preferably 0.1 MPa. Above, more preferably 0.5 MPa or more. On the other hand, the upper limit is preferably 10 MPa or less, more preferably 5 MPa or less. In addition, the timing which peels the separator 11a is not limited before thermosetting.

(Dicing process)
Subsequently, the sealing body 16 may be diced (see FIG. 2E). Thereby, the hollow package 18 in the SAW chip 13 unit can be obtained.

(Board mounting process)
If necessary, a substrate mounting process can be performed in which rewiring and bumps are formed on the hollow package 18 and mounted on a separate substrate (not shown). For mounting the hollow package 18 on the substrate, a known device such as a flip chip bonder or a die bonder can be used.

  In the above-described embodiment, the case where the support of the present invention is the printed wiring board 12 has been described. However, the support of the present invention is not limited to this example, and may be, for example, a ceramic substrate, a silicon substrate, a metal substrate, or the like. Also good.

  In the following, preferred embodiments of the present invention will be described in detail by way of example. However, the materials, blending amounts, and the like described in the examples are not intended to limit the scope of the present invention only to those unless otherwise specified.

The components used in Examples and Comparative Examples will be described.
Epoxy resin: YSLV-80XY manufactured by Nippon Steel Chemical Co., Ltd. (bisphenol F type epoxy resin, Epokin equivalent: 200 g / eq., Softening point: 80 ° C.)
Phenol resin: LVR8210DL (Novolak type phenol resin, hydroxyl equivalent: 104 g / eq., Softening point: 60 ° C.) manufactured by Gunei Chemical Co., Ltd.
Thermoplastic resin: ME-2000M manufactured by Negami Kogyo Co., Ltd. (carboxyl group-containing acrylic ester polymer, weight average molecular weight: about 600,000, Tg: -35 ° C., acid value: 20 mgKOH / g, polymer concentration 20% methyl ethyl ketone) solution)
Carbon black: # 20 manufactured by Mitsubishi Chemical
Alumina particles 1: manufactured by Admatechs (average particle size: 3 μm, maximum particle size: 15 μm), 3-methacryloxypropyltrimethoxysilane treated product Alumina particles 2: manufactured by Admatechs (average particle size: 1.5 μm, maximum) Particle size: 8 μm), 3-methacryloxypropyltrimethoxysilane treated product Boron nitride secondary aggregate: manufactured by Momentive, product name: AC6091 (average particle size: 125 μm, maximum particle size: 200 μm, sieve classified product)
Curing accelerator: 2PHZ-PW (2-phenyl-4,5-dihydroxymethylimidazole) manufactured by Shikoku Kasei Kogyo Co., Ltd.

[Production of sealing resin sheet]
According to the blending ratio shown in Table 1, each component was dissolved and dispersed in methyl ethyl ketone as a solvent to obtain a varnish having a concentration of 90% by weight. The varnish was applied on a release treatment film made of a polyethylene terephthalate film having a thickness of 38 μm after the release treatment of silicone, and then dried at 110 ° C. for 3 minutes. The obtained sheet having a thickness of 60 μm was laminated to obtain a thermosetting resin sheet having a thickness of 300 μm.

(Measurement of thermal conductivity after thermosetting)
First, the sealing resin sheets of Examples and Comparative Examples were heated at 150 ° C. for 30 minutes to be thermoset. Thermosetting was performed under normal pressure.
Next, the thermal conductivity of these sealing resin sheets after thermosetting was measured. The thermal conductivity was obtained from the following formula. The results are shown in Table 1.
(Thermal conductivity) = (thermal diffusion coefficient) x (specific heat) x (specific gravity)

<Thermal diffusion coefficient>.
After producing the resin sheet for sealing, it heated at 150 degreeC for 30 minutes under normal pressure. Using this sample, the thermal diffusion coefficient was measured using a xenon flash method calorimeter (manufactured by Netch Japan Co., Ltd., LFA447 nanoflash).

<Specific heat>
It calculated | required by the measuring method according to the specification of JIS-7123 using DSC (The product made from TA instrument, Q-2000).

<Specific gravity>
Measurement was performed by the Archimedes method using an electronic balance (manufactured by Shimadzu Corporation, AEL-200).

(Measurement of viscosity of sealing resin sheet at 90 ° C.)
The viscosity at 90 ° C. of the sealing resin sheets prepared in Examples and Comparative Examples was measured by a parallel plate method using a rheometer (MAAKE III, manufactured by HAAKE). More specifically, the temperature was raised from 50 ° C. to 90 ° C. under the conditions of a gap of 0.8 mm, a parallel plate diameter of 8 mm, a measurement frequency of 1 Hz, a strain amount of 0.05%, and a temperature increase rate of 30 ° C./min. The viscosity was measured for 3 minutes while maintaining the temperature, and the minimum viscosity at that time was read. The results are shown in Table 1.

(Sealability evaluation)
A SAW chip having the following specifications on which an aluminum comb-shaped electrode was formed was mounted on a ceramic substrate under the following bonding conditions to produce a SAW chip mounting substrate including the ceramic substrate and the SAW chip mounted on the ceramic substrate. The gap width between the SAW chip and the ceramic substrate was 20 μm.

<SAW chip>
Chip size: 1.2 mm square (thickness 150 μm)
Bump material: Au (height 20 μm)
Number of bumps: 6 bumps Number of chips: 100 (10 x 10)

<Bonding conditions>
Equipment: manufactured by Panasonic Electric Works Co., Ltd. Bonding conditions: 200 ° C., 3N, 1 sec, ultrasonic output 2W

A sealing resin sheet was disposed on the SAW chip mounting substrate.
Next, under the conditions shown below, the SAW chip was embedded in the sealing resin sheet by vacuum pressing using a parallel plate method.

<Vacuum press conditions>
Temperature: 60 ° C
Applied pressure: 4 MPa
Degree of vacuum: 1.6 kPa
Press time: 1 minute

  After opening to atmospheric pressure, a thermosetting treatment was performed under the following conditions.

<Thermosetting conditions>
Temperature: 150 ° C
Applied pressure: None (under normal pressure)
Heating time: 60 minutes

  The obtained sealing body was peeled off at the interface between the substrate and the sealing resin (sealing resin sheet) to expose the element surface of the SAW chip. Then, it observed with the optical microscope. The sealing resin sheet has good followability with respect to the SAW chip, and the case where the SAW chip is sealed without a void between the SAW chip and the sealing resin sheet is indicated as “◯”. The case where the followability of the resin sheet was poor and the SAW chip was sealed with a void between the SAW chip and the sealing resin sheet was evaluated as “x”. The results are shown in Table 1.

DESCRIPTION OF SYMBOLS 11 Resin sheet | seat for hollow sealing 11a Support body 13 SAW chip 16 Sealing body 18 Hollow package

Claims (5)

Containing inorganic fillers,
The inorganic filler includes alumina particles,
The content of the alumina particles is 50% by volume or more with respect to the whole inorganic filler,
The maximum particle size of the alumina particles is in the range of 10 μm or more and 50 μm or less,
A resin sheet for sealing, wherein the thermal conductivity in the sheet thickness direction after thermosetting is 3 W / m · K or more. The inorganic filler further includes boron nitride,
2. The sealing resin sheet according to claim 1, wherein a content of the boron nitride is 5% by volume or more with respect to the entire inorganic filler.   The resin sheet for sealing according to claim 2, wherein the thermal conductivity in the sheet thickness direction after thermosetting is 5 W / m · K or more.   The resin sheet for sealing according to any one of claims 1 to 3, wherein the surface of the alumina particles is hydrophobized with a silane coupling agent.   The electronic device apparatus which has the resin sheet for sealing of any one of Claims 1-4.

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