JP6379051B2 - Hollow electronic device sealing sheet - Google Patents

Description

  The present invention relates to a sheet for sealing a hollow electronic device.

  Conventionally, when a hollow electronic device package having a hollow structure between an electronic device and a substrate is resin-sealed to produce a hollow electronic device package, a sheet-shaped sealing resin is often used. Yes (see, for example, Patent Document 1).

JP 2006-19714 A

  As a manufacturing method of the package, a sheet-shaped sealing resin is disposed on one or a plurality of electronic devices disposed on an adherend, and then the direction in which the electronic device and the sheet-shaped sealing resin are brought close to each other There is a method in which the electronic device is embedded in a sheet-shaped sealing resin by applying pressure to the sheet, and then the sheet-shaped sealing resin is thermally cured. The sheet-shaped sealing resin used for such a manufacturing method may be used in the state laminated | stacked on the separator. Specifically, the electronic device is embedded in the sheet-shaped sealing resin in a state where the separator and the sheet-shaped sealing resin are laminated, and then the separator is peeled off at an appropriate timing. Thereby, it can suppress that the surface (top surface) opposite to the electronic device embedding surface is contaminated.

  However, conventionally, unevenness sometimes occurs between the place where the electronic device is arranged below and the place where the electronic device is not arranged on the top surface of the sheet-shaped sealing resin.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to suitably embed an electronic device in a thermosetting sealing sheet, and to provide unevenness on the top surface of the thermosetting sealing sheet. It is providing the sheet | seat for hollow type electronic device sealing which makes it possible to obtain the suppressed hollow type electronic device.

  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 sheet for sealing a hollow electronic device according to the present invention is
Having a separator and a thermosetting sealing sheet,
The product of the thickness (mm) of the separator and the tensile modulus (N / mm ² ) at 25 ° C. is 200 N / mm or more,
The minimum melt viscosity in the range of 50 to 100 ° C. of the thermosetting sealing sheet is 100 kPa · s or more.

According to the said structure, since the product of the thickness (mm) of a separator and the tensile elasticity modulus (N / mm < ² >) in 25 degreeC is 200 N / mm or more and the intensity | strength of a separator is high, when embedding an electronic device, It can suppress that an unevenness | corrugation arises in the top | upper surface of the sheet | seat for thermosetting sealing.
Moreover, in addition to the high strength of the separator, the minimum melt viscosity in the range of 50 ° C. to 100 ° C. of the thermosetting sealing sheet is set to 100 kPa · s or more, and when the electronic device is embedded, the thermosetting sealing The sheet was not too soft. As a result, it is possible to suppress the formation of irregularities on the top surface of the thermosetting sealing sheet when the electronic device is embedded.
Moreover, since the minimum melt viscosity in the range of 50 ° C. to 100 ° C. of the thermosetting sealing sheet is 100 kPa · s or more, the penetration of the resin into the hollow portion of the electronic device is suppressed.

  The said structure WHEREIN: It is preferable that the thickness of the said separator is 50 micrometers or more.

When the thickness of the separator is 50 μm or more, the product of the thickness (mm) of the separator and the tensile modulus (N / mm ² ) is easily set to 200 N / mm or more.

It is a cross-sectional schematic diagram of the sheet | seat for hollow type electronic device sealing which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the hollow type electronic device package which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the hollow type electronic device package which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the hollow type electronic device package which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the hollow type electronic device package which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the hollow type electronic device package which concerns on this embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited only to these embodiments.

(Hollow type electronic device sealing sheet)
FIG. 1 is a schematic cross-sectional view of a hollow electronic device sealing sheet according to the present embodiment. As shown in FIG. 1, the hollow electronic device sealing sheet 10 includes a separator 11 a and a thermosetting sealing sheet 11 laminated on the separator 11 a (hereinafter also referred to as “sealing sheet 11”). With. The separator 11a corresponds to the separator of the present invention.
In addition, although this embodiment demonstrates the sheet | seat for hollow type electronic device sealing, when a separator is laminated | stacked only on one side of the sheet | seat for thermosetting sealing, this invention is not limited to this example. Moreover, the separator may be laminated | stacked on both surfaces of the sheet | seat for thermosetting sealing. In this case, one separator can be peeled off immediately before use.
Moreover, although this embodiment demonstrates the case where the sheet | seat for thermosetting sealing is laminated | stacked in contact with a separator on a separator, this invention is not limited to this example, For separator and thermosetting sealing You may have another layer between sheets.

(Separator)
The separator 11a has a product of thickness (mm) and tensile elastic modulus (N / mm ² ) at 25 ° C. of 200 N / mm or more, preferably 250 N / mm or more, and preferably 300 N / mm or more. Is more preferable. Since the product of the thickness (mm) of the separator 11a and the tensile modulus (N / mm ² ) is 200 N / mm or more and the strength of the separator is high, the top surface of the sealing sheet 11 when embedding an electronic device It is possible to suppress the occurrence of unevenness on the surface.
In the present invention, the product of the thickness and the tensile elastic modulus is used as an indicator of the strength of the separator to suppress the occurrence of unevenness on the top surface if the tensile elastic modulus is high even if the thickness is thin. This is because the present inventors have conceived that even if the tensile modulus is low, if the thickness is large, it is possible to suppress the occurrence of unevenness on the top surface. And as a result of earnest research, the present inventor is able to suppress the occurrence of unevenness on the top surface of the thermosetting sealing sheet when the electronic device is embedded when the product is 200 N / mm or more. I found it.

The thickness of the separator 11a is preferably 50 μm or more, more preferably 75 μm or more, and further preferably 100 μm or more. When the thickness of the separator 11a is 50 μm or more, the product of the thickness (mm) of the separator 11a and the tensile elastic modulus (N / mm ² ) is easily set to 200 N / mm or more. The upper limit of the thickness of the separator 11a is not particularly limited, but can be set to 200 μm or less from the viewpoint of easy peeling.

Tensile modulus of the separator 11a is preferably at 1000 N / mm ² or more, more preferably 3000N / mm ² or more, further preferably 4000 N / mm ² or more. When the tensile elastic modulus of the separator 11a is 1000 N / mm ² or more, the product of the thickness (mm) of the separator 11a and the tensile elastic modulus (N / mm ² ) is easily set to 200 N / mm or more. The measuring method of the tensile elastic modulus of the separator 11a is based on the method described in the examples.

  Specific materials constituting the separator 11a include, for example, a paper-based substrate such as paper; a fiber-based substrate such as cloth, nonwoven fabric, felt, and net; a metal-based substrate such as metal foil and metal plate; Plastic base materials such as rubber base materials such as rubber sheets, foams such as foam sheets, and laminates thereof [particularly, laminates of plastic base materials and other base materials, or between plastic sheets An appropriate thin leaf body such as a laminate and the like] can be used. In the present invention, a plastic base material can be suitably used. Examples of the plastic base material include olefin resins such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymer; ethylene-vinyl acetate copolymer (EVA), ionomer resin, ethylene- (Meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer such as ethylene copolymer; polyethylene terephthalate (PET), polyethylene naphthalate (PEN), Polyester such as polybutylene terephthalate (PBT); Acrylic resin; Polyvinyl chloride (PVC); Polyurethane; Polycarbonate; Polyphenylene sulfide (PPS); Amide resin such as polyamide (nylon) and wholly aromatic polyamide (aramid); Teruketon (PEEK); polyimides; polyetherimides; polyvinylidene chloride; ABS (acrylonitrile - butadiene - styrene copolymer); cellulosic resins; silicone resins; and fluorine resins. Of these, polyethylene terephthalate, polyethylene naphthalate, or polyimide is preferable. This is because polyethylene terephthalate, polyethylene naphthalate, and polyimide are materials that tend to increase the tensile modulus. The separator 11a may be a single layer or two or more layers. In addition, as a manufacturing method of the separator 11a, it can form by a conventionally well-known method.

  The separator 11a may be subjected to a release treatment on the surface or may not be subjected to a release treatment.

  Examples of the release agent used for the release treatment include a fluorine-based release agent, a long-chain alkyl acrylate release agent, and a silicone release agent. Of these, silicone release agents are preferred.

(Thermosetting sealing sheet)
As for the sheet | seat 11 for sealing, the minimum melt viscosity in the range of 50 to 100 degreeC is 100 kPa * s or more, It is preferable that it is 150 kPa * s or more, It is more preferable that it is 200 kPa * s or more. Moreover, the upper limit of the minimum melt viscosity is not particularly limited, but can be set to, for example, 600 kPa · s or less from the viewpoint of hollow sealing properties. In the present embodiment, in addition to the high strength of the separator 11a, the minimum melt viscosity in the range of 50 ° C. to 100 ° C. of the thermosetting sealing sheet is 100 kPa · s or more, and when embedding an electronic device, The sealing sheet 11 was configured not to be too soft. As a result, it is possible to suppress the formation of irregularities on the top surface of the sealing sheet 11 when the electronic device is embedded.
Moreover, since the minimum melt viscosity in the range of 50 ° C. to 100 ° C. of the sealing sheet 11 is 100 kPa · s or more, the ingress of the resin into the hollow portion of the electronic device is suppressed.

  It is preferable that the sealing sheet 11 includes an epoxy resin and a phenol resin. 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 toughness of the epoxy resin after curing and the reactivity of the epoxy resin, it is preferably a solid at an ordinary temperature with an epoxy equivalent of 150 to 250, a softening point or a melting point of 50 to 130 ° C. From the viewpoint of reliability, bisphenol F type epoxy resin, bisphenol A type epoxy resin, biphenyl type epoxy resin and the like are more preferable.

  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.

  From the viewpoint of reactivity with the epoxy 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., and in particular, from the viewpoint of high curing reactivity and low cost. A phenol novolac resin can be preferably 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 lower limit of the total content of the epoxy resin and the phenol resin in the sealing sheet 11 is preferably 5.0% by weight or more, and more preferably 7.0% by weight or more. Adhesive force with respect to an electronic device, a board | substrate, etc. is acquired favorably as it is 5.0 weight% or more. On the other hand, the upper limit of the total content is preferably 25% by weight or less, and more preferably 20% by weight or less. When the content is 25% by weight or less, the hygroscopicity of the sealing sheet can be reduced.

  It is preferable that the sealing sheet 11 includes a thermoplastic resin. Thereby, the heat resistance of the obtained sealing sheet, flexibility, and intensity | strength can be improved.

  As thermoplastic resins, natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, thermoplasticity Polyimide resin, polyamide resin such as 6-nylon and 6,6-nylon, phenoxy resin, acrylic resin, saturated polyester resin such as PET and PBT, polyamideimide resin, fluorine resin, styrene-isobutylene-styrene block copolymer, etc. Can be mentioned. These thermoplastic resins can be used alone or in combination of two or more. Especially, an acrylic resin is preferable from a viewpoint that a flexibility is easy to obtain and a dispersibility with an epoxy resin is favorable.

  The acrylic resin is not particularly limited, and includes 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. Examples thereof include a polymer (acrylic copolymer) as a component. 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.

  The glass transition temperature (Tg) of the acrylic resin is preferably 50 ° C. or lower, more preferably −70 to 20 ° C., and further preferably −50 to 0 ° C. By setting the temperature to 50 ° C. or less, the sheet can have flexibility.

  Among the acrylic resins, those having a weight average molecular weight of 50,000 or more are preferable, those having 100,000 to 2,000,000 are more preferable, and those having 300,000 to 1,600,000 are more preferable. Within the above numerical range, the viscosity and flexibility of the sealing sheet 11 can be further increased. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

  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. Among these, from the viewpoint that the viscosity of the sealing sheet 11 can be increased by reacting with the epoxy resin, it contains at least one of a carboxyl group-containing monomer, a glycidyl group (epoxy group) -containing monomer, and a hydroxyl group-containing monomer. preferable.

  0.5 weight% or more is preferable and, as for content of the thermoplastic resin in the sheet | seat 11 for sealing, 1.0 weight% or more is more preferable. When the content is 0.5% by weight or more, the flexibility and flexibility of the sealing sheet can be obtained. The content of the thermoplastic resin in the sealing sheet 11 is preferably 10% by weight or less, and more preferably 5% by weight or less. Adhesiveness of the sheet | seat for sealing with respect to an electronic device or a board | substrate is favorable in it being 10 weight% or less.

  It is preferable that the sealing sheet 11 contains an inorganic filler.

  The inorganic filler is not particularly limited, and various conventionally known fillers can be used. For example, quartz glass, talc, silica (such as fused silica and crystalline silica), alumina, aluminum nitride, nitriding Examples thereof include silicon and boron nitride powders. These may be used alone or in combination of two or more. Among these, silica and alumina are preferable, and silica is more preferable because the linear expansion coefficient can be satisfactorily reduced.

  As silica, silica powder is preferable, and fused silica powder is more preferable. Examples of the fused silica powder include spherical fused silica powder and crushed fused silica powder. From the viewpoint of fluidity, spherical fused silica powder is preferable.

  It is preferable that the sealing sheet 11 contains an inorganic filler in the range of 69 to 86% by volume. The content is more preferably 75% by volume or more, and still more preferably 78% by volume or more. When the inorganic filler is contained in the range of 69 to 86% by volume, the thermal expansion coefficient can be made closer to the SAW chip 13. As a result, package warpage can be suppressed. Furthermore, when the inorganic filler is contained within the range of 69 to 86% by volume, the water absorption rate can be lowered.

  When the inorganic filler is silica, the content of the inorganic filler can also be described in units of “wt%”. The content of silica in the sealing sheet 11 is preferably 80 to 92% by weight, and more preferably 85 to 92% by weight.

The average particle size of the inorganic filler is preferably 20 μm or less, more preferably 0.1 to 15 μm, and particularly preferably 0.5 to 10 μm. preferable.
Further, as the inorganic filler, two or more inorganic fillers having different average particle diameters may be used. When two or more kinds of inorganic fillers having different average particle diameters are used, the above-mentioned “average particle diameter of the inorganic filler is 20 μm or less” means that the average particle diameter of the whole inorganic filler is 20 μm or less.

  The shape of the inorganic filler is not particularly limited, and may be any shape such as a spherical shape (including an ellipsoidal shape), a polyhedron shape, a polygonal column shape, a flat shape, and an indeterminate shape. From the viewpoint of achieving a high filling state and appropriate fluidity, a spherical shape is preferred.

The inorganic filler contained in the sealing sheet 11 preferably has two peaks in the particle size distribution measured by a laser diffraction scattering method. Such an inorganic filler can be obtained, for example, by mixing two kinds of inorganic fillers having different average particle diameters. When an inorganic filler having two peaks in the particle size distribution is used, the inorganic filler can be filled at a high density. As a result, it is possible to increase the content of the inorganic filler.
The two peaks are not particularly limited, but the peak on the larger particle size side is preferably in the range of 3 to 30 μm, and the peak on the smaller particle size side is preferably in the range of 0.1 to 1 μm. . When the two peaks are within the numerical range, the content of the inorganic filler can be further increased.
Specifically, the particle size distribution is obtained by the following method.
(A) The sealing sheet 11 is put into a crucible and ignited at 700 ° C. for 2 hours in an air atmosphere to be incinerated.
(B) The obtained ash content is dispersed in pure water and subjected to ultrasonic treatment for 10 minutes, and the particle size distribution using a laser diffraction scattering type particle size distribution measuring device (“LS 13 320”; wet method) manufactured by Beckman Coulter, Inc. (Volume basis) is obtained.
The composition of the sealing sheet 11 is an organic component other than the inorganic filler, and substantially all the organic components are burned away by the above-described strong heat treatment. Therefore, the obtained ash is regarded as the inorganic filler and the measurement is performed. Do. The average particle size can be calculated simultaneously with the particle size distribution.

  The sealing sheet 11 is preferably surface-treated in advance with an inorganic filler with a silane coupling agent.

  The silane coupling agent is not particularly limited as long as it has a methacryloxy group or an acryloxy group and can perform a surface treatment of the inorganic filler. Specific examples of the silane coupling agent include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryloxy. Examples include octyltrimethoxysilane and methacryloxyoctyltriethoxysilane. Of these, 3-methacryloxypropyltrimethoxysilane is preferable from the viewpoint of reactivity and cost.

  When the surface of the inorganic filler is treated with a silane coupling agent, outgas (for example, methanol) is generated. Therefore, if the inorganic filler is surface-treated with a silane coupling agent in advance before the sealing sheet 11 is formed, a certain amount of outgas can be eliminated at this stage. As a result, the amount of outgas trapped in the sheet at the time of producing the sealing sheet 11 can be suppressed, and the generation of voids can be reduced.

When the sealing sheet 11 contains an inorganic filler that has been surface-treated in advance with a compound having a methacryloxy group or an acryloxy group as a silane coupling agent, the inorganic filler is 100 parts by weight of the inorganic filler. It is preferable that the surface treatment is performed in advance with 0.5 to 2 parts by weight of the silane coupling agent.
If the surface treatment of the inorganic filler is performed with the silane coupling agent, the viscosity of the sealing sheet 11 can be reduced. However, if the amount of the silane coupling agent is large, the outgas generation amount increases. Therefore, even if the inorganic filler is surface-treated in advance, the performance of the sealing sheet 11 is deteriorated by 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 inorganic filler is 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 inorganic filler, the viscosity can be suitably reduced and the performance degradation due to outgassing can be reduced. Can be suppressed.

The sealing sheet 11 contains a methacryloxy group as a silane coupling agent or an inorganic filler that has been surface-treated in advance with a compound having an acryloxy group, and the inorganic filler has an average particle size. When using a mixture of two types of inorganic fillers having different diameters, it is preferable to surface-treat at least the inorganic filler having a smaller average particle diameter with a silane coupling agent in advance. Since the inorganic filler having a smaller average particle diameter has a larger specific surface area, an increase in viscosity can be further suppressed.
Moreover, when using what mixed two types of inorganic fillers from which an average particle diameter differs as said inorganic filler, both the inorganic filler with a smaller average particle diameter and the larger inorganic filler are previously made into silane. It is more preferable to surface-treat with a coupling agent. In this case, the increase in viscosity can be further suppressed.

  It is preferable that the sealing sheet 11 includes a curing accelerator.

  The curing accelerator is not particularly limited as long as it cures the epoxy resin and the phenol resin, and examples thereof include organic phosphorus compounds such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate; 2-phenyl-4, And imidazole compounds such as 5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Of these, imidazole compounds are preferred because they have good reactivity and are easy to increase the Tg of the cured product.

  As for content of a hardening accelerator, 0.1-5 weight part is preferable with respect to a total of 100 weight part of an epoxy resin and a phenol resin.

  The sheet | seat 11 for sealing may contain a flame retardant component as needed. 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.

  It is preferable that the sealing sheet 11 contains a pigment. The pigment is not particularly limited, and examples thereof include carbon black.

  The content of the pigment in the sealing 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 sheet | seat for sealing 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.

  Although the thickness of the sheet | seat 11 for sealing is not specifically limited, For example, it is 100-2000 micrometers. An electronic device can be favorably sealed as it is in the said range.

  The sealing sheet 11 may have a single layer structure or a multilayer structure in which two or more sealing sheets are laminated.

[Method for producing sheet for encapsulating hollow electronic device]
The hollow electronic device sealing sheet 10 is prepared by dissolving and dispersing a resin or the like for forming the sealing sheet 11 in an appropriate solvent to adjust the varnish, so that the varnish has a predetermined thickness on the separator 11a. After the coating film is applied to form a coating film, the coating film can be formed by drying under predetermined conditions. 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.
As another method, after the varnish is applied on a support to form a coating film, the coating film may be dried under the drying conditions to form the sealing sheet 11. Thereafter, the sealing sheet 11 is bonded to the separator 11a together with the support. In particular, when the sealing sheet 11 includes a thermoplastic resin (acrylic resin), an epoxy resin, and a phenol resin, all of these are dissolved in a solvent, and then applied and dried. Examples of the solvent include methyl ethyl ketone, ethyl acetate, toluene and the like.

[Method of manufacturing hollow electronic device package]
The method for manufacturing the hollow package according to the present embodiment is as follows:
Preparing a laminate in which one or more electronic devices are fixed on an adherend;
A step of preparing a sheet for sealing a hollow electronic device;
Arranging the hollow electronic device sealing sheet on the electronic device of the laminate; and
At least a step of embedding the electronic device in a thermosetting sealing sheet of the hollow electronic device sealing sheet, and forming a sealing body in which the electronic device is embedded in the thermosetting sealing sheet. Including.

  The adherend is not particularly limited, and examples thereof include a printed wiring board, a ceramic substrate, a silicon substrate, and a metal substrate. In the present embodiment, the SAW chip 13 mounted on the printed wiring board 12 is hollow-sealed with the sealing sheet 11 to produce a hollow package. The SAW chip 13 is a chip having a SAW (Surface Acoustic Wave) filter. That is, in this embodiment, a case where the electronic device of the present invention is a chip having a SAW (Surface Acoustic Wave) filter will be described.

(Process of preparing a laminate)
In the method for manufacturing a hollow package according to the present embodiment, first, a laminate 15 in which a plurality of SAW chips 13 (SAW filters 13) are mounted on a printed wiring board 12 is prepared (see FIG. 2). 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.

(Process for preparing a sheet for sealing a hollow electronic device)
Moreover, in the manufacturing method of the hollow package which concerns on this embodiment, the sheet | seat 10 (refer FIG. 1) for hollow type electronic device sealing is prepared.

(Process of arranging a sheet for sealing a hollow electronic device)
Next, as shown in FIG. 3, the laminate 15 is disposed on the lower heating plate 22 with the surface on which the SAW chip 13 is fixed facing upward, and the hollow electronic device is sealed on the surface of the SAW chip 13. A stop sheet 10 is arranged. In this step, the laminated body 15 may be first disposed on the lower heating plate 22, and then the hollow electronic device sealing sheet 10 may be disposed on the laminated body 15. The electronic device sealing sheet 10 may be laminated first, and then a laminate in which the laminate 15 and the hollow electronic device sealing sheet 10 are laminated may be disposed on the lower heating plate 22.

(Process of arranging a sheet for sealing a hollow electronic device)
Next, as shown in FIG. 4, heat pressing is performed by the lower heating plate 22 and the upper heating plate 24 to embed the SAW chip 13 in the sealing sheet 11, and the SAW chip 13 is embedded in the sealing sheet 11. The sealed body 25 is formed. The sealing sheet 11 functions as a sealing resin for protecting the SAW chip 13 and its accompanying elements from the external environment. Thereby, the sealing body 25 in which the SAW chip 13 is embedded in the sealing sheet 11 is obtained.

  Specifically, as hot press conditions for embedding the SAW chip 13 in the sealing sheet 11, the temperature is preferably 40 to 150 ° C., more preferably 60 to 120 ° C., and the pressure is, for example, 0. The pressure is 1 to 10 MPa, preferably 0.5 to 8 MPa, and the time is, for example, 0.3 to 10 minutes, preferably 0.5 to 5 minutes. Examples of the hot press method include a parallel plate press and a roll press. Of these, a parallel plate press is preferable.

Thereby, an electronic device in which the SAW chip 13 is embedded in the sealing sheet 11 can be obtained. In view of improving the adhesion and followability of the sealing sheet 11 to the SAW chip 13 and the printed wiring board 12, it is preferable to press the sheet under reduced pressure.
As the pressure reduction conditions, the pressure is, for example, 0.1 to 5 kPa, preferably 0.1 to 100 Pa, and the pressure reduction holding time (time from the pressure reduction start to the press start) is, for example, 5 to 600 seconds. Yes, preferably 10 to 300 seconds.

(Separator peeling process)
Next, the separator 11a is peeled off (see FIG. 5).

(Thermosetting process)
Next, the sealing sheet 11 is thermally cured. As the conditions for the thermosetting treatment, 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. Moreover, you may pressurize as needed, Preferably it is 0.1 Mpa or more, More preferably, it is 0.5 Mpa or more. On the other hand, the upper limit is preferably 10 MPa or less, more preferably 5 MPa or less.

(Dicing process)
Subsequently, the sealing body 25 may be diced (see FIG. 6). Thereby, the hollow package 18 (hollow type electronic device package) in units of the SAW chip 13 can be obtained.

(Board mounting process)
If necessary, a substrate mounting step can be performed in which 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 hollow electronic device of the present invention is the SAW chip 13 which is a semiconductor chip having a movable part has been described. However, the hollow electronic device of the present invention is not limited to this example as long as it has a hollow portion between the adherend and the electronic device. For example, it may be a semiconductor chip having MEMS (Micro Electro Mechanical Systems) such as a pressure sensor and a vibration sensor as the movable part.
Further, in the above-described embodiment, the case where the electronic device is embedded with a parallel plate press using the hollow electronic device sealing sheet has been described. However, the present invention is not limited to this example, and the vacuum in a vacuum state is used. In the chamber, the laminate of the electronic device and the hollow electronic device sealing sheet is sealed with a release film, and then a gas at atmospheric pressure or higher is introduced into the chamber so that the electronic device is sealed with the hollow electronic device. It may be embedded in the thermosetting sealing sheet of the stop sheet. Specifically, the electronic device may be embedded in the thermosetting sealing sheet of the hollow electronic device sealing sheet by the method described in JP2013-52424A. Even in this case, in the hollow electronic device sealing sheet of the present invention, the product of the thickness (mm) of the separator and the tensile elastic modulus (N / mm ² ) at 25 ° C. is 200 N / mm or more. Therefore, it is possible to suppress the occurrence of unevenness on the top surface of the thermosetting sealing sheet when the electronic device is embedded. Moreover, since the minimum melt viscosity in the range of 50 ° C. to 100 ° C. of the thermosetting sealing sheet is 100 kPa · s or more, the top surface of the thermosetting sealing sheet is uneven when embedding an electronic device. Generation | occurrence | production can be suppressed and the approach of resin to the hollow part of an electronic device can be suppressed.

  Hereinafter, 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 of the sealing sheet used in the examples will be described.
Epoxy resin: YSLV-80XY manufactured by Nippon Steel Chemical Co., Ltd. (bisphenol F type epoxy resin, epkin equivalent 200 g / eq., Softening point 80 ° C.)
Phenol resin: LVR8210DL (Novolak-type phenol resin, hydroxyl group equivalent 104 g / eq., Softening point 60 ° C.) manufactured by Gunei Chemical
Thermoplastic resin: HME-2006M (manufactured by Negami Kogyo Co., Ltd. (carboxyl group-containing acrylate copolymer, weight average molecular weight: about 600,000, glass transition temperature (Tg): −35 ° C.)
Inorganic filler A: FB-5SDC manufactured by Denki Kagaku Kogyo Co., Ltd. (average particle size 5 μm, surface treatment pear)
Inorganic filler B: A surface treatment of SO-25R (average particle size 0.5 μm) manufactured by Admatex with 3-methacryloxypropyltrimethoxysilane (product name: KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). Surface treatment with 1 part by weight of silane coupling agent with respect to 100 parts by weight of inorganic filler B.
Carbon black: # 20 manufactured by Mitsubishi Chemical
Curing accelerator: 2PHZ-PW (2-phenyl-4,5-dihydroxymethylimidazole) manufactured by Shikoku Kasei Kogyo Co., Ltd.

[Creation of Electronic Device Sealing Sheets According to Examples and Comparative Examples]
According to the compounding ratio of the sealing sheet described in Table 1, each component was dissolved and dispersed in methyl ethyl ketone as a solvent to obtain a varnish having a concentration of 85% by weight. After applying this varnish on the separator of the kind and thickness of Table 1, it was dried at 110 degreeC for 5 minute (s). As a result, a sheet having a thickness of 55 μm was obtained. Four sheets of this sheet were laminated to prepare a sealing sheet for hollow sealing having a thickness of 220 μm. All separators are subjected to silicone release treatment on the surface. In Table 1, PEN means polyethylene naphthalate, and PET means polyethylene terephthalate.

(Measurement of minimum viscosity of sealing sheet)
The minimum viscosity of the sealing sheets prepared in Examples and Comparative Examples was measured by a parallel plate method using a rheometer (HAAKE, MARS III). More specifically, the viscosity is measured in the range of 50 ° C. to 130 ° C. under the conditions of a gap of 1 mm, a parallel plate diameter of 8 mm, a rotational speed of 5 s ⁻¹ , a strain of 0.05%, and a heating rate of 10 ° C./min. In this case, the minimum viscosity at 50 ° C. to 100 ° C. was defined as the minimum viscosity. The results are shown in Table 1.

(Tensile elastic modulus of separator at 25 ° C)
About the separator of an Example and a comparative example, the storage elastic modulus in 25 degreeC was measured using the viscoelasticity measuring apparatus (Rheometrics company_made: type | formula: RSA-III). More specifically, the separator is cut so that the sample size is 30 mm long × 10 mm wide, the measurement sample is set in a film tensile measurement jig, and the frequency is 1.0 Hz in the temperature range of −30 to 100 ° C., the strain is 0. The measurement was performed under the conditions of 025% and a heating rate of 10 ° C./min, and the measured value at 25 ° C. was read. The results are shown in Table 1.
Table 1 also shows the product (N / mm) of the thickness of the separator and the tensile elastic modulus.

(Evaluation of top surface unevenness)
First, the following four chips were prepared.
Chip size (plan view): 3mm square
Chip height: 200 μm
Chip hollow gap (hollow part height): 15 μm
Next, the prepared chips were arranged at the four corners (upper left, lower left, upper right, lower right) so that the distance between the chips was 300 μm. The inter-chip distance refers to the closest distance between the chips.For example, the inter-chip distance between the upper left chip and the upper right chip is the right edge of the upper left chip and the left edge of the upper right chip. The distance between.
Next, the sheet | seat for electronic device sealing of an Example and a comparative example was arrange | positioned on the chip | tip surface. At this time, the chip surface and the sealing sheet were arranged so as to be in contact with each other.
Next, the chip was embedded in a sealing sheet by vacuum pressing under conditions of 75 ° C., 60 seconds, and a pressure of 300 kPa. The degree of vacuum at this time was 1.6 kPa.
Next, it heated at 150 degreeC for 1 hour.
After that, the separator is peeled off, and the difference between the thickness of the portion where the chip is present at the lower portion and the thickness of the central portion of the sealing sheet in which the four chips are embedded (the portion where the chip is not present at the lower portion) is defined as the dent amount. Asked. For the measurement, a contact surface roughness meter (Veeco, DEKTAK8) was used. The case where the amount of dents was 30 μm or less was evaluated as ◯, and the case where it was larger than 30 μm was evaluated as ×. The results are shown in Table 1.

(Evaluation of resin penetration into package hollow)
A SAW chip mounting substrate in which a SAW chip having the following specifications on which aluminum comb-shaped electrodes were formed was mounted on a ceramic substrate under the following bonding conditions was produced. The gap width between the SAW chip and the ceramic substrate was 15 μm.

<SAW chip>
Chip size: 1.2 mm square (thickness 150 μm)
Bump material: Au (height 15 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

  On the obtained SAW chip mounting substrate, each sealing sheet was attached by a vacuum press under the heating and pressing conditions shown below.

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

  After opening to atmospheric pressure, the sealing sheet was thermally cured in a hot air dryer at 150 ° C. for 1 hour to obtain a sealed body. Cleavage the substrate and sealing resin interface of the obtained sealing body, and the entry of the resin into the hollow part between the SAW chip and the ceramic substrate by the product name “Digital Microscope” (200 times) manufactured by KEYENCE The amount was measured. The resin penetration amount was determined by measuring the maximum reach distance of the resin that entered the hollow portion from the end of the SAW chip, and setting this as the resin penetration amount. In addition, when there was no entry and the hollow portion spread outside the SAW chip, the resin entry amount was expressed as minus. The case where the resin penetration amount was −50 μm to 50 μm was evaluated as “◯”, and the case where it was less than −50 μm or larger than 50 μm was evaluated as “X”. The results are shown in Table 1.

10 Hollow type electronic device sealing sheet 11 Thermosetting sealing sheet (sealing sheet)
11a Separator 13 SAW filter 15 Laminated body 18 Hollow electronic device package 25 Sealed body

Claims (2)

Having a separator and a thermosetting sealing sheet,
The product of the thickness (mm) of the separator and the tensile modulus (N / mm ² ) at 25 ° C. is 200 N / mm or more,
A hollow electronic device sealing sheet, wherein the thermosetting sealing sheet has a minimum melt viscosity of 100 kPa · s or more in a range of 50 ° C to 100 ° C. The sheet for sealing a hollow electronic device according to claim 1, wherein the separator has a thickness of 50 μm or more.

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