JP2017190396A - Sealing resin sheet and method of manufacturing electronic component device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing resin sheet excellent in workability which is capable of simultaneously and collectively sealing both surfaces of a wiring board having electronic components mounted thereon, and a method capable of efficiently manufacturing an electronic component device including a wiring board whose both surfaces are resin-sealed using the sealing resin sheet.SOLUTION: The sealing resin sheet to be used for sealing electronic components is obtained by molding a thermosetting resin composition into a sheet and has a specific gravity of 0.80 or less. The method of manufacturing an electronic component device includes the steps of: arranging the sealing resin sheets on both surfaces of a wiring board having electronic components mounted thereon; and simultaneously heat-curing the sealing resin sheets to seal both surfaces of the wiring board.SELECTED DRAWING: None

Description

  The present invention relates to a sealing resin sheet and an electronic component device manufacturing method using the same.

  Electronic components such as wiring boards and ICs and diodes mounted on wiring boards are required to have impact resistance, for example, for mobile and in-vehicle use, and are used in amusement applications and ATMs (automated teller machines). For example, confidentiality may be required. In this case, conventionally, it has been generally performed to seal an electronic component using a liquid thermoplastic resin composition for potting or a thermosetting resin pellet for transfer molding. However, all of these require dedicated equipment and the process is complicated. Furthermore, since the former liquid thermoplastic resin composition has low heat resistance and is easily decomposed, there is also a problem that it is difficult to sufficiently maintain confidentiality.

  Recently, for these problems, thermosetting resin sheets have been developed that can be sealed just by placing them in a required part and heating them (see, for example, Patent Document 1). First, a resin sheet is externally processed to a required size and shape, placed in a required portion, and then heated and melted to embed the wiring on the wiring board and the entire mounted electronic component in the resin. Unlike the prior art, no special equipment is required and the work is easy.

  However, when trying to seal the entire wiring board on which electronic components are mounted using the resin sheet, it is not possible to seal the wiring board as in the conventional case, and both sides of the wiring board are individually sealed. It was necessary to stop. That is, first, hold the wiring board horizontally, seal the electronic components mounted on the front surface (upper surface), then hold the back surface facing up, and seal the electronic components mounted on the back surface Had to do. This is because even if an attempt is made to seal at the same time as the front surface with the back surface facing down, the resin melted evenly does not sag or does not sag. In particular, when the sheet thickness exceeded 0.5 mm, it was difficult to perform double-sided simultaneous sealing.

  In order to solve the problem of such resin sag or uneven resin thickness, for example, measures such as increasing the thixotropy of the resin or increasing the viscosity can be considered. Embedding may be insufficient. Although a method of holding the wiring substrate vertically and simultaneously sealing both surfaces is also conceivable, there is no change in that the resin sagging and the resin thickness are uneven.

  For this reason, there is a need for a sealing resin sheet excellent in workability that can simultaneously seal both surfaces of a wiring board having electronic components mounted on both front and back surfaces.

JP 2007-329162 A

  The present invention has been made to solve the above-described problems of the prior art. For example, it is possible to simultaneously seal both surfaces of a wiring board on which electronic components are mounted. An object of the present invention is to provide a method for efficiently producing an electronic component device provided with a wiring board having both surfaces sealed with resin by using the sealing resin sheet and the sealing resin sheet. It is said.

  As a result of intensive research to achieve the above object, the present inventors have made the sheet sag and the resin thickness even when both sides of the wiring board are simultaneously sealed by setting the sheet specific gravity to a specific value or less. It has been found that the bias can be prevented or suppressed, and the present invention has been completed.

  That is, the molding resin sheet according to one aspect of the present invention is a sealing resin sheet used for sealing an electronic component, and is formed by molding a thermosetting resin composition into a sheet shape, 0.80 It has the following specific gravity.

Moreover, the manufacturing method of the electronic component device according to another aspect of the present invention includes the step of placing the sealing resin sheet on both surfaces of the wiring board on which the electronic component is mounted, and heating the sealing resin sheet simultaneously. And a step of curing and sealing both surfaces of the wiring board.

  ADVANTAGE OF THE INVENTION According to this invention, the resin sheet for sealing excellent in workability | operativity which can seal both surfaces simultaneously collectively with respect to the wiring board with which the electronic component was mounted is obtained. Using the sealing resin sheet, it is possible to efficiently manufacture an electronic component device including a wiring board on which both surfaces are resin-sealed.

It is a figure explaining the manufacturing method of the electronic component apparatus using the resin sheet for sealing of this invention. It is a figure which shows typically an example of the electronic component apparatus manufactured by the conventional method. It is a figure which shows typically the other example of the electronic component apparatus manufactured by the conventional method.

  Embodiments of the present invention will be described below.

[Resin sheet for sealing]
The sealing resin sheet of the present invention is used for the purpose of protecting the wiring on the wiring board and the electronic components such as ICs and diodes mounted on the wiring board from the external atmosphere, mechanical shock, etc. It is used for the purpose and maintains a solid sheet shape at room temperature. When heated, it melts and cures to complete sealing.

  The sealing resin sheet of the present invention is obtained by molding a thermosetting resin composition into a sheet shape and has a specific gravity of 0.80 or less. When the specific gravity exceeds 0.80, when both sides of the wiring board on which the electronic component is mounted are simultaneously sealed, the resin droops or the resin thickness becomes uneven, and the electronic component or wiring is not sealed. Become complete. The specific gravity is preferably 0.75 or less, and more preferably 0.70 or less. In addition, this specific gravity is a value measured based on JISK6911.

  The sealing resin sheet of the present invention has a minimum melt viscosity of 1 Pa · s or more when a melt viscosity is measured using a rheometer or the like at a temperature increase rate of 2 ° C./min to 5 ° C./min. The melting point (melting peak temperature) measured in accordance with JIS K 7121 using a differential scanning calorimeter (DSC) is preferably 40 ° C. or higher and 90 ° C. or lower. . If the minimum melt viscosity is less than 1 Pa · s, resin sag or uneven resin thickness tends to occur during sealing, and if it exceeds 1000 Pa · s or less, voids are likely to occur and electronic components are not sufficiently embedded. There is a risk. Also, if the melting point is less than 40 ° C, it tends to be sticky at room temperature and the handleability is reduced, and if the melting point exceeds 90 ° C, the melting slows and the resin begins to cure, so the melt viscosity does not decrease and the electronic components can be embedded. May be insufficient. The minimum melt viscosity is more preferably 1 Pa · s to 800 Pa · s, and even more preferably 5 Pa · s to 500 Pa · s. The melting point is more preferably 50 ° C. or higher and 85 ° C. or lower.

  In addition, the sealing resin sheet of the present invention is heated at a temperature of 100 ° C. or higher and lower than 180 ° C. for 3 minutes to 1 hour (for example, 100 ° C. for 1 hour, 180 ° C. for 3 minutes, 120 ° C. for 20 minutes). It is preferable to perform primary curing. When the heating time is long, the workability of the sealing work is deteriorated, and when the heating time is short, the void may be broken or the leveling may not be sufficiently performed. Further, when the heating temperature is low, it is difficult to cure in 1 hour or less, and when the heating temperature is high, curing proceeds in less than 3 minutes.

  If the sealing resin sheet of this invention is a sheet form, the planar shape will not be specifically limited. In general, a rectangular sheet is used, but the sheet is not limited to this as long as the shape is suitable for sealing an electronic component.

  Also, the thickness is not particularly limited, but is usually 100 μm or more and 3.0 mm or less, preferably 150 μm or more and 2.0 mm or less. If the thickness of the sheet is less than 100 μm, there is a concern that the thickness may vary from the viewpoint of blending the hollow inorganic filler. On the other hand, when the thickness exceeds 3.0 mm, the moldability is deteriorated and the handleability at room temperature is also deteriorated. In use, although depending on the height, shape, material, etc. of the electronic component to be sealed, the height of the electronic component to be sealed is generally one time the thickness of the sealing resin sheet. It is preferable to select and use a sheet having a thickness of 2 times or less, preferably 1 time or more and 1.5 times or less. At this time, a plurality of sheets may be laminated and used depending on the thickness of the sealing resin sheet to be used. If the sheet thickness for electronic components (the total when multiple sheets are stacked) is too thick, not only will the material be wasted, but voids will likely remain, making it difficult to reduce the thickness of the electronic component device. Become. Conversely, if it is too thin, sealing may be insufficient.

  The encapsulating resin sheet of the present invention is obtained by molding a thermosetting resin composition into a sheet shape. Thermosetting resin compositions include, for example, epoxy resins, polyimide resins, bismaleimide triazine modified resins, thermosetting polyphenylene ether resins, etc., and thermosetting resins generally used for sealing and bonding electronic components. The composition based on this is mentioned. Among these, an epoxy resin-based composition is preferable.

Hereinafter, an epoxy resin-based composition suitable for the present invention will be described.
The composition based on this epoxy resin contains (A) an epoxy resin, (B) a curing agent for epoxy resin, and (C) a hollow inorganic filler.

  As the epoxy resin of component (A), the combined use of (A1) solid epoxy resin and (A2) liquid epoxy resin is preferable. The solid epoxy resin (A1) is an epoxy resin that is solid at room temperature, and the liquid epoxy resin (A2) is an epoxy resin that is liquid at room temperature.

（式中、ｎは０以上の整数を表す）

（式中、ｎは０以上の整数を表す） As the solid epoxy resin (A1), for example, a biphenyl aralkyl type epoxy resin having a softening point of 50 ° C. or more and 80 ° C. or less, a bisphenol A type epoxy resin having a softening point of 50 ° C. or more and 80 ° C. or less, and a softening point of 50 Examples thereof include phenol novolac type epoxy resins having a temperature of from 100 ° C. to 100 ° C.
The biphenyl aralkyl type epoxy resin having a softening point of 50 ° C. or higher and 80 ° C. or lower is a biphenyl aralkyl type epoxy resin represented by the following general formula (1) having a softening point of 50 ° C. or higher and 80 ° C. or lower. The bisphenol A type epoxy resin having a softening point of 50 ° C. or more and 80 ° C. or less is a bisphenol A type epoxy resin represented by the following general formula (2) having a softening point of 50 ° C. or more and 80 ° C. or less. .

(In the formula, n represents an integer of 0 or more)

(In the formula, n represents an integer of 0 or more)

Specific examples of commercially available biphenyl aralkyl epoxy resins having a softening point of 50 ° C. or higher and 80 ° C. or lower include, for example, NC-3000 (trade name, manufactured by Nippon Kayaku Co., Ltd., softening point 56 ° C.), NC-3000H. (Nippon Kayaku Co., Ltd. brand name, softening point 71 degreeC) etc. are mentioned. In addition, specific examples of commercially available bisphenol A type epoxy resins having a softening point of 50 ° C. or higher and 80 ° C. or lower include, for example, jER1001 (trade name, manufactured by Mitsubishi Chemical Corporation, softening point 64 ° C.), jER1002 (Mitsubishi Chemical). Product name, softening point 78 ° C.) Furthermore, specific examples of commercially available phenol novolac epoxy resins having a softening point of 50 ° C. or higher and 100 ° C. or lower include EPICLON N-770 (trade name, softening point 70 ° C. manufactured by DIC Corporation). It is done.
These solid epoxy resins may be used individually by 1 type, and 2 or more types may be mixed and used for them.

The liquid epoxy resin as the component (A2) can be used without particular limitation to the molecular structure and the like as long as it is liquid at room temperature having two or more epoxy groups in one molecule. Specific examples thereof include bisphenol A type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins and the like; phenol novolac type epoxy resins, Novolak type epoxy resins such as cresol novolac type epoxy resins; glycidyl ester type epoxy resins such as hexahydrophthalic anhydride type epoxy resins, tetrahydrophthalic anhydride type epoxy resins, dimer acid type epoxy resins; N, N-diglycidylaniline, N , N-diglycidyl toluidine, diaminodiphenylmethane type glycidylamine, glycidylamine type epoxy resins such as aminophenol type glycidylamine; biphenyl type epoxy resin, styrene Examples include ben-type epoxy resins, triphenolmethane-type epoxy resins, triphenolpropane-type epoxy resins, alkyl-modified triphenolmethane-type epoxy resins, dicyclopentadiene-modified phenol-type epoxy resins, naphthol-type epoxy resins, and naphthalene-type epoxy resins. . These liquid epoxy resins may be used individually by 1 type, and 2 or more types may be mixed and used for them. (A2) The liquid epoxy resin is preferably a bisphenol liquid epoxy resin, and more preferably a bisphenol A liquid epoxy resin.
Specific examples of commercially available bisphenol A type liquid epoxy resins suitable as the component (A2) include, for example, jER828 (trade name, manufactured by Mitsubishi Chemical Corporation), EPICLON850 (trade name, manufactured by DIC Corporation), and the like. It is done.

  The component (A1) and the component (A2) are preferably used so that the mass ratio (A1) :( A2) is in the range of 60:40 to 90:10. If the ratio of the component (A1) is less than the above range, it tends to be sticky at room temperature and it may be difficult to form a sheet that can be handled. On the other hand, when the proportion of the component (A1) exceeds the above range, the handling at the time of use becomes difficult, for example, the flexibility at normal temperature is impaired and it becomes easy to break at the time of handling. The mass ratio (A1) :( A2) between the component (A1) and the component (A2) is preferably in the range of 65:35 to 85:15, and more preferably in the range of 70:30 to 80:20. preferable.

  (B) As a hardening | curing agent of a component, if it is normally used for hardening of an epoxy resin, such as a phenol resin-type hardening | curing agent, an acid anhydride type hardening | curing agent, an amine-type hardening | curing agent, it can use without a restriction | limiting in particular.

  Examples of phenolic resin-based curing agents include phenol novolac resins, cresol novolac resins and other novolac type phenol resins obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde, and these novolac type phenol resins. Examples thereof include epoxidized or butylated modified novolak type phenolic resin, dicyclopentadiene modified phenolic resin, paraxylene modified phenolic resin, phenol aralkyl resin, naphthol aralkyl resin, triphenolalkane type phenolic resin, polyfunctional type phenolic resin and the like.

  Examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, hexahydro Phthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis trimellitate, glycerol tristrimitate, maleic anhydride, succinic anhydride, dodecenyl succinic anhydride Examples include acid, methylcyclohexene dicarboxylic acid anhydride, alkylstyrene-maleic anhydride copolymer, chlorendic acid anhydride, polyazeline acid anhydride, and the like.

  Examples of amine curing agents include, for example, aliphatic polyamines such as diethylenetriamine, triethylenetetramine, m-xylenediamine, and 2-methylpentamethylenediamine; 1,3-bisaminomethylcyclohexane, bis (4-aminocyclohexyl) ) Cycloaliphatic polyamines such as methane, norbornenediamine and 1,2-diaminocyclohexane; Piperazine-type polyamines such as N-aminoethylpiperazine and 1,4-bis (2-amino-2-methylpropyl) piperazine; Diaminophenylmethane M-phenylenediamine, diaminodiphenylsulfone, diethyltoluenediamine, 1-methyl-3,5-diethyl-2,6-diaminobenzene, 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1, 3,5-triethyl-2,6 Diaminobenzene, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,5,3 ', aromatic polyamines such as 5'-tetramethyl-4,4'-diaminodiphenylmethane and the like.

In addition, dicyandiamide represented by the following structural formula, which is known as a latent curing agent, is used. In particular, as the component (A), a biphenyl aralkyl type epoxy resin having a softening point of 50 ° C. or higher and 80 ° C. or lower, a bisphenol A type epoxy resin having a softening point of 50 ° C. or higher and 80 ° C. or lower, or a softening point of 50 ° C. or higher and 100 ° C. or lower. When a phenol novolac type epoxy resin is used, it is preferable to use dicyandiamide.

(B) The hardening agent of a component may be used individually by 1 type, and 2 or more types may be mixed and used for it.
Moreover, the compounding quantity of the hardening | curing agent of (B) component is about 0.5-15 mass parts with respect to 100 mass parts of total amounts of the epoxy resin of (A) component, for example in the case of dicyandiamide, Preferably it is 1 -10 parts by mass.

The hollow inorganic filler of component (C) is a fine hollow powder that contains fine bubbles when granulating an inorganic material such as glass or ceramic. The specific gravity of the sealing resin sheet of the present invention is the same as that described above. It is a component that greatly contributes to the predetermined value. Preferably this true density of the hollow inorganic filler is 0.50 g / cm ³ or less, more preferably 0.45 g / cm ³ or less. When the true density of the hollow inorganic filler exceeds 0.5 g / cm ³ , it is difficult to set the specific gravity of the sealing resin sheet to the predetermined value described above. The average particle size of the hollow inorganic filler is preferably 30 μm or more and 70 μm, and more preferably 40 μm or more and 60 μm. When the average particle size of the hollow inorganic filler is less than 30 μm, it is difficult to obtain a preferable blending ratio described later, and when it exceeds 70 μm, it is difficult to obtain a preferable sheet thickness. Specific examples of such commercially available hollow inorganic fillers include 3M ^TM Glass Bubbles (trade name, manufactured by 3M Japan), which is a hollow glass filler. The hollow inorganic filler may be subjected to a surface treatment with a coupling agent. By using such a surface-treated material, the dispersibility can be enhanced. These hollow inorganic fillers may be used alone or in a combination of two or more. The average particle diameter of the hollow inorganic filler refers to a particle diameter (D50) at which the integrated volume is 50% in the measured particle size distribution. In the present specification, unless otherwise specified, simply the average particle diameter or D50 When writing, it is used in this sense.

  Low-density hollow fillers include not only hollow inorganic fillers as described above, but also organic hollow fillers made of, for example, acrylic resin, thermal expansion type hollow fillers, etc. These hollow organic fillers Is not suitable for use in the present invention and is preferably not used because it crushes during kneading or changes in specific gravity during heating.

  The hollow inorganic filler of component (C) is 25% by mass or more and 60% by mass or less on a mass basis and 52% by volume or more and 80% by volume on a volume basis with respect to the entire composition from the viewpoint of the specific gravity and mechanical strength of the sheet. The following ranges are preferable, and a range of 30% by mass to 55% by mass and more preferably 60% by mass to 77% by volume on a volume basis is more preferable.

  In addition to the above components, the epoxy resin composition may contain a curing accelerator that accelerates the reaction between the epoxy resin of component (A) and the curing agent for epoxy resin of component (B). Examples of the curing accelerator include imidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-undecylimidazole, 1,2-dimethylimidazole, and 2,4-dimethylimidazole. 2-phenylimidazole, 2-phenyl-4-methylimidazole, 4-methylimidazole, 4-ethylimidazole, 2-phenyl-4-hydroxymethylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2- Methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl- 2-phenyl-4,5-di (cyanoethoxy) methylimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 1-benzyl-2-phenylimidazole hydrochloride, 1-benzyl-2-phenylimidazo Lithium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1 ')]-Ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl 4'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, imidazoles such as 2-phenylimidazoline; 1,8-diazabicyclo [5,4,0] undecene-7 (DBU), 1,5-diazabicyclo [4,3,0] nonene, 5,6-dibutylamino-1,8-diazabicyclo [5,4,0] undecene-7 Diazabicyclo compounds and salts thereof; tertiary amines such as triethylamine, triethylenediamine, benzyldimethylamine, α-methylbenzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol; metaphenylenediamine Diaminodiphenyl meta Aromatic amines such as diaminodiphenylsulfone; aromatic dimethylureas such as phenyldimethylurea, methylenebis (phenyldimethylurea), tolylenebis (dimethylurea); trimethylphosphine, triethylphosphine, tributylphosphine, diphenylphosphine, triphenylphosphine , Tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, methyldiphenylphosphine, dibutylphenylphosphine, tricyclohexylphosphine, bis (diphenylphosphino) methane, 1,2-bis (diphenylphosphino) ethane, etc. Organic phosphine compounds; tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, triphenylphosphine Tetra such re phenyl borane - or triphenyl boron salts. These may be used individually by 1 type, and may mix and use 2 or more types.

  The blending amount of the curing accelerator is preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin as the component (A). If the blending amount is less than 0.1 parts by mass, the curability is not very effective. On the other hand, if it exceeds 10 parts by mass, the storage stability may be lowered.

  When dicyandiamide is used alone as the curing agent for component (B), it is preferable to use imidazoles, tertiary amines, aromatic amines, and aromatic dimethylureas as curing accelerators. This is because the curing temperature of dicyandiamide is as high as 160 to 180 ° C, and by using imidazoles, tertiary amines, aromatic amines, and aromatic dimethylureas, lower temperatures (for example, temperatures below 160 ° C) This is because it is possible to cure with. Further, from the viewpoint of enhancing the storage stability of the composition and the sealing resin sheet, it is preferable to use imidazoles and aromatic dimethylureas.

  In the epoxy resin composition, a coupling agent can be blended for the purpose of improving the filling property and the adhesion between the hollow inorganic filler and the resin and the resin. Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, an aluminum chelate, an aluminum / zirconium-based compound, and among them, a silane coupling agent is preferable.

  Examples of preferred silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacrylic). Ropropyl) trimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyl Trimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, methyltrimethoxy Silane, me Le triethoxysilane, vinyl trimethoxysilane, vinyl triacetoxy silane, imidazole silane, and the like. These may be used individually by 1 type, and may mix and use 2 or more types.

  The blending amount of the coupling agent is preferably in the range of 0.01 to 5% by mass of the entire composition. When the blending amount is less than 0.01% by mass of the whole composition, there is not much effect on the improvement of the characteristics by addition, and when it exceeds 5% by mass, the moisture resistance reliability decreases.

  The epoxy resin composition further includes elastomers such as synthetic rubber, phenoxy resin, and modified polyamide resin, diluents, antifoaming agents, anti-aging agents, antioxidants, plastics, and the like, which are generally blended with this type of composition. Additives such as agents, pigments, dyes, colorants and the like can be blended as necessary within a range not impairing the effects of the present invention. Moreover, you may mix | blend inorganic fillers other than a hollow inorganic filler, if it is a range which does not inhibit the effect of this invention. Examples of the inorganic filler other than the hollow inorganic filler include, for example, fused silica, crystalline silica, crushed silica, synthetic silica, oxide powder such as alumina, titanium oxide, and magnesium oxide, and hydroxide powder such as aluminum hydroxide and magnesium hydroxide. And nitride powders such as boron nitride, aluminum nitride, and silicon nitride.

  The preparation of such an epoxy resin composition comprises (A) an epoxy resin, (B) a curing agent for epoxy resin, (C) a hollow inorganic filler, and various components to be blended as necessary. It is carried out by sufficiently kneading using a mixer such as a mixer or a planetary stirrer. After kneading, if necessary, defoaming treatment may be performed.

  The sealing resin sheet of the present invention can be obtained, for example, by molding a kneaded product of the above epoxy resin composition into a sheet shape by a method such as rolling or casting. In that case, you may make it laminate a release film on both surfaces of a sheet | seat. By laminating the release film, it is possible to prevent the resin sheet from drying and to maintain its shape. As the release film, for example, a commercially available film binder NSD (trade name, manufactured by Fujimori Kogyo Co., Ltd .; having a non-silicone release layer on a 50 μm PET film) is used.

[Method of manufacturing electronic component device]
Next, the manufacturing method of the electronic component apparatus using the sealing resin sheet of this invention is demonstrated.
FIG. 1 is a diagram schematically showing a manufacturing process of an electronic component device using the sealing resin sheet of the present invention.
As shown in FIG. 1, in the method for manufacturing an electronic component device of the present invention, first, a process of bonding and fixing the electronic component 12 to both surfaces of the wiring board 11 is performed. Each electronic component 12 has an external connection electrode (not shown), and the external connection electrode and a wiring pattern formed on the surface of the wiring board are connected by solder or the like to form a circuit. It is mounted on the wiring board 11 (FIG. 1A).

Next, the sealing resin sheet 20 of the present invention that has been externally processed into a predetermined planar shape in advance is disposed and bonded to both surfaces of the wiring board 11 on which the electronic component 12 is mounted (FIG. 1B). ). When the release films on both surfaces of the sealing resin sheet 20 are laminated, the release films are previously peeled off.
In this step, the sealing resin sheet 20 does not have to be completely bonded to the electronic component 12 or the wiring substrate 11 and may be temporarily bonded, but the sealing surface of the sealing resin sheet 20 (the electronic component 12 or the wiring substrate) may be used. It is preferable that the entire surface facing the substrate 11 is in contact with the electronic component 12 and the wiring board 11. Thereby, in the next sealing step, the heated and melted resin is leveled by the capillary force and the surface tension between the electronic components 12, so that the surface of the electronic components and the wiring board is satisfactorily covered. Such temporary adhesion is performed, for example, by press molding at a temperature of 60 ° C. or higher and 180 ° C. or lower and a low pressure of 0.5 MPa or lower under normal pressure.

Thereafter, the wiring board 11 with the sealing resin sheet 20 temporarily bonded on both sides is put into a drying furnace while being held vertically (FIG. 1 (c)) or horizontally (FIG. 1 (d)). The sealing resin sheet 20 is simultaneously heated. The heated sealing resin sheet 20 melts and flows, and the melted and fluidized resin enters between the electronic components 12 and the electronic components 12 are embedded. Thereafter, the heating is further continued to cure the heated and melted resin. This completes the sealing.
This sealing step may be performed at 100 ° C. to 180 ° C., preferably 110 ° C. to 170 ° C. for 5 minutes to 60 minutes, preferably 10 minutes to 50 minutes. Thereafter, the resin is preferably heated at 150 ° C. to 200 ° C. for 2 hours to 5 hours so that the resin is completely cured.

In the present invention, since the specific gravity of the encapsulating resin sheet 20 is 0.8 or less, even if the encapsulating resin sheet 12 is heated and melted, the resin may sag, It is possible to manufacture a highly reliable electronic component device in which the electronic component 12 is securely and satisfactorily sealed without causing a large deviation and being cured with a substantially uniform thickness.
2 shows an example in which the conventional sealing resin sheet 21 is used and the sealing process is performed while the wiring substrate 11 is held vertically, and FIG. 3 uses the conventional sealing resin sheet 21. In the case where the sealing process is carried out while holding the wiring substrate 11 horizontally, the thickness of the sealing resin sheet 21 is biased as a result of the resin sagging when heated and melted. This results in insufficient sealing of the upper electronic component.

  The sealing resin sheet of the present invention does not cause resin sag even if both sides of the wiring board on which the electronic component is mounted are simultaneously packaged. Therefore, the electronic component mounted on the wiring board or the wiring board is sealed. As the sealing resin sheet to be used, it is particularly useful for applications in which both surfaces of the wiring substrate are simultaneously sealed.

  Examples of electronic components on a wiring board that are sealed using the sealing resin sheet of the present invention include semiconductor devices such as ICs, diodes, thyristors, transistors, MEMS, crystal resonators, piezoelectric resonators, and the like. Examples include various vibrators, acceleration sensors, various sensors such as angular velocity sensors, and surface acoustic wave devices such as surface acoustic wave filters.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all. In the following description of Examples and Comparative Examples, “part” means “part by mass” unless otherwise specified.

<Preparation of sealing resin sheet>
Example 1
12 parts of bisphenol A type liquid epoxy resin (trade name BE-188EL manufactured by Changchun Artificial Resin Co., Ltd .; epoxy equivalent 193 g / eq), phenol novolak type solid epoxy resin (trade name EPICLON N-770 manufactured by DIC Corporation); epoxy equivalent 213 g / eq, softening point 70 ° C. 50 parts, dicyandiamide (trade name DICY, manufactured by Nippon Carbide Co., Ltd.), imidazole curing accelerator (trade name: Curesol C17Z, manufactured by Shikoku Kasei Co., Ltd.) 0.15 part, hollow glass Filler (trade name 3M ^TM Glass Bubbles K37 manufactured by 3M Japan Ltd., 33 parts average particle size 45 μm, true density 0.37 g / cm ³ ), and epoxysilane (trade name JH-0187 manufactured by Sun Chemical Co., Ltd.) After mixing 0.85 parts, the filler is kneaded with a hot roll at 120 ° C. To obtain an epoxy resin composition Hamaritsu 33 wt% (60 vol%).
The epoxy resin composition was passed through a roll heated to 80 ° C. through a release film to prepare a sealing resin sheet (A) having a thickness of 0.7 mm.

(Examples 2-3, Comparative Example 1)
An epoxy resin composition was prepared in the same manner as in Example 1 except that the composition was changed as shown in Table 1. Further, a sealing resin sheet (B) (Example) was prepared using the obtained composition. 2) A sealing resin sheet (C) (Example 3) and a sealing resin sheet (D) (Comparative Example 1) were produced. In Comparative Example 1, in place of the hollow glass filler, fused silica powder (Denka Co., Ltd., trade name: Denka fused silica FB-210; average particle size 22 μm, true density 1.7 g / cm ³ ) was filled with filler. The ratio was 75% by mass (60% by volume).

About the resin sheet for sealing obtained in each said Example and each comparative example, (1) specific gravity, (2) minimum melt viscosity, and (3) melting | fusing point (melting peak temperature) were measured by the method shown below. The results are shown in Table 1 together with the composition and sheet thickness.
(1) Specific gravity Measured according to JIS K 6991.
(2) Minimum melt viscosity A parallel plate type rheometer (manufactured by TA Instruments) was used to measure the temperature by raising the temperature from 50 ° C to 120 ° C at a heating rate of 5 ° C / min, and the minimum melt viscosity was measured.
(3) Melting point (melting peak temperature)
Measured according to JIS K 7121 (temperature increase rate 10 ° C./min).

<Manufacture of electronic component devices>
Example 4
Prepare a total of 36 printed circuit boards with 6 rows each of vertical and horizontal electronic components measuring 5 mm in length, 3.5 mm in width, and 0.5 mm in height, 4 mm apart on both sides. The sealing resin sheet (A) obtained in Example 1 cut into a size and shape covering up to 10 mm around the electronic component was temporarily bonded. The temporary bonding was performed by applying a pressure of 0.05 MPa with a press heated to 80 ° C. In addition, the sealing resin sheet leaves the release films on both sides until temporary press-bonding. First, the release film on one side is peeled off, and the peeled surface is arranged toward the wiring board, and the temporary press-bonding is performed. Thereafter, the release film on the other side was peeled off.
After provisional pressure bonding, as shown in FIG. 1 (c), the wiring board is put into a drying furnace in a state of being held vertically, heated from room temperature to 100 ° C. over 5 minutes, and then at 100 ° C. for 1 hour. The resin sheet for sealing was heated to cure the electronic component device.

(Examples 5-6, Comparative Example 2)
An electronic component device was manufactured in the same manner as in Example 4 except that the sealing resin sheets (B), (C), and (D) obtained in Example 2, Example 3, and Comparative Example 1 were used. did.

  The thickness of the sealing part (cured sealing resin sheet) of the electronic component device manufactured in Examples 4 to 6 and Comparative Example 2 is set to five upper portions and five lower portions per sealing resin sheet. Measurements were made with a micrometer at several locations, and the maximum and minimum values were determined. The measurement was performed on a total of 10 sheets in each example, and the average value was calculated. The results are shown in Table 2. Table 2 also shows the heating time (including the temperature raising time) during sealing.

  As is apparent from Table 2, in the electronic component devices of Examples 4 to 6 manufactured using the sealing resin sheet of the present invention, even when the wiring substrate is held vertically and both surfaces are simultaneously sealed simultaneously While a sealing portion having a substantially uniform thickness could be formed, in Comparative Example 2, a large deviation in thickness occurred.

(Example 7)
After temporarily sealing the sealing resin sheet (A), an electronic component device was manufactured in the same manner as in Example 4 except that the wiring board was held horizontally and placed in a drying furnace and subjected to heat treatment.

(Examples 8 to 9, Comparative Example 3)
An electronic component device was manufactured in the same manner as in Example 7 except that the sealing resin sheets (B), (C), and (D) obtained in Example 2, Example 3, and Comparative Example 1 were used. did.

(Comparative Example 4)
Comparative Example 3 except that the temporary pressure bonding and heat curing of the sealing resin sheet were individually performed on the front and back surfaces of the wiring substrate, and the wiring substrate was turned over and the back surface was directed upward. In the same manner, an electronic component device was manufactured.
The thickness of the sealing portion (sealing resin sheet after curing) of the electronic component device manufactured in Examples 7 to 9 and Comparative Examples 3 to 4 on the lower side of the wiring board is defined as the sealing resin. Each sheet was measured with a micrometer at 10 locations, and the maximum and minimum values were obtained. The measurement was performed on a total of 10 sheets in each example, and the average value was calculated. The results are shown in Table 3. Table 3 also shows the heating time (including the temperature raising time) at the time of sealing.

  As is clear from Table 3, in the electronic component devices of Examples 7 to 9 manufactured using the sealing resin sheet of the present invention, even when the wiring board is held horizontally and both surfaces are simultaneously sealed simultaneously Whereas a sealing portion having a substantially uniform thickness could be formed on the lower surface side of the wiring board, in Comparative Example 3, a large deviation occurred in the thickness, and the front and back surfaces of the wiring board were individually sealed. In Comparative Example 4 to which the conventional method was applied, the heat sealing time approximately twice that of Examples 7 to 9 was required.

  In the sealing resin sheet of the present invention, even if both surfaces of the wiring substrate are simultaneously sealed, the resin does not sag and the thickness is less uneven. Therefore, it is useful as an encapsulating resin sheet for encapsulating a wiring board or an electronic component mounted on the wiring board, particularly for applications in which both surfaces of the wiring board are simultaneously encapsulated.

  DESCRIPTION OF SYMBOLS 11 ... Wiring board, 12 ... Electronic component, 20 ... Resin sheet | seat for sealing

Claims (6)

A resin sheet for sealing used for sealing electronic components,
A sealing resin sheet comprising a thermosetting resin composition formed into a sheet shape and having a specific gravity of 0.80 or less.   2. The sealing resin sheet according to claim 1, wherein the specific gravity is 0.75 or less.   A sealing resin sheet having a minimum melt viscosity of 1 Pa · s or more and 1000 Pa · s or less.   The said thermosetting resin composition contains (A) epoxy resin, (B) the hardening | curing agent for epoxy resins, and (C) hollow inorganic filler, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. Sealing resin sheet. The resin sheet for sealing according to claim 4, wherein the component (C) is a hollow inorganic filler having a true density of 0.5 g / cm ³ or less. Placing the sealing resin sheet according to any one of claims 1 to 5 on both sides of a wiring board on which electronic components are mounted;
And a step of simultaneously curing the resin sheet for sealing to seal both surfaces of the wiring board.

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