JP2018103584A - Resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin sheet capable of suppressing the amount of resin entering a hollow portion between an electronic device and an adherend from varying for each package. SOLUTION: The outermost layer contains an inorganic filler and a thermoplastic resin, and the content of the inorganic filler is 85% by weight or more based on the entire outermost layer. The content of the resin is 15% by weight or less based on the entire resin component of the outermost layer, and the innermost layer contains a functional group-containing thermoplastic resin having a weight average molecular weight of 800,000 or more, and contains a functional group-containing thermoplastic resin. The amount of the resin sheet is 90% by weight or more based on the entire resin component of the innermost layer. [Selection diagram] Fig. 1

Description

  The present invention relates to a resin sheet.

  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).

  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.

  When the above-described method is adopted, a part of the sealing resin enters the hollow portion between the electronic device and the adherend. However, there has been a problem that the variation in the amount of penetration is large for each package.

  Patent Document 2 discloses a sealing epoxy resin composition sheet having a two-layer structure of an A layer and a B layer. In Patent Document 2, it is described that an A layer is placed on a hollow device and a B layer is placed on the hollow device so as to be covered and sealed.

JP 2006-19714 A JP 2011-219726 A

  However, the A layer of Patent Document 2 uses a semi-cured epoxy resin, and the epoxy resin that is a relatively low molecule before curing flows during the curing reaction. It cannot be secured.

  This invention is made | formed in view of the subject mentioned above, The objective is resin which can suppress that the quantity of resin which enters into the hollow part between an electronic device and a to-be-adhered body varies for every package. To provide a sheet.

  In order to achieve the above object, the present inventor first conducted intensive research on the reason why the amount of resin entering the hollow portion varies from package to package. As a result, when the above-described method is adopted, after embedding the electronic device in the sealing resin, at the time of thermosetting, first, a part of the sealing resin becomes low viscosity due to heat and flows into the hollow part. After entering, it was found that the resin became highly viscous with thermosetting, and the resin entry was stopped. The amount of resin flow at the time of thermosetting was greatly different for each package, and it was found difficult to control.

  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 resin sheet according to the present invention is
Having an outermost layer and an innermost layer,
The outermost layer includes an inorganic filler and a thermoplastic resin,
The content of the inorganic filler is 85% by weight or more with respect to the entire outermost layer,
The content of the thermoplastic resin is 15% by weight or less based on the entire resin component of the outermost layer,
The innermost layer includes a functional group-containing thermoplastic resin having a weight average molecular weight of 800,000 or more,
Content of the said functional group containing thermoplastic resin is 90 weight% or more with respect to the whole resin component of the said innermost layer, It is characterized by the above-mentioned.

The resin sheet is used by embedding the electronic device after being laminated on the electronic device so that the innermost layer is in contact therewith.
According to the said structure, the said innermost layer contains the functional group containing thermoplastic resin in the ratio of 90 weight% or more with respect to the whole resin component of the said innermost layer. Since there are many thermoplastic resin components, resin can be entrapped in the hollow part between an electronic device and a to-be-adhered body at the time of embedding an electronic device.
Moreover, since the said functional group containing thermoplastic resin has a functional group, it bridge | crosslinks after embedding an electronic device until thermosetting is complete | finished. In addition, the functional group-containing thermoplastic resin has a weight average molecular weight of 800,000 or more, and thus hardly flows even when heated. Therefore, the amount of resin entering (moving amount) in the hollow portion between the electronic device and the adherend can be reduced.
Here, since the innermost layer contains a functional group-containing acrylic resin in a proportion of 90% by weight or more with respect to the entire resin component of the innermost layer in order to realize a stable hollow sealing property, The elastic modulus is low. For this reason, if it is attached to a dicing tape at the time of dicing, it becomes difficult to peel from the dicing tape after dicing. In addition, acrylic resin is easy to follow the chip during molding due to its viscoelasticity, but since it does not flow, the dent between the chips becomes large, and the end part has a shape when the chip is separated into pieces. It becomes a concave shape.
Therefore, in the present invention, the outermost layer is provided. The outermost layer contains an inorganic filler in a proportion of 85% by weight or more with respect to the entire outermost layer. Further, the outermost layer has a thermoplastic resin content of 15% by weight or less based on the entire resin component of the outermost layer, and contains a large amount of an epoxy resin component having high fluidity. As a result, the elastic modulus after curing is increased and the peelability from the dicing tape is improved. Moreover, since the outermost layer has high fluidity before curing, the resin flows. As a result, the dent on the top surface, that is, the dent between the chips can be suppressed.

  The said structure WHEREIN: It is preferable that the said functional group containing thermoplastic resin is a glycidyl group containing acrylic resin.

  When the functional group-containing thermoplastic resin is a glycidyl group-containing acrylic resin, it is possible to further reduce the flow of the resin under the chip after the electronic device is embedded until the thermosetting is completed.

In the above configuration, the innermost layer includes a phenol resin as a curable component,
The content of the phenol resin is preferably within a range of an equivalent ratio of 0.8 to 2.0 with respect to the functional group-containing thermoplastic resin.

  When the content of the phenol resin contained in the innermost layer is within a range of 0.8 to 2.0 equivalent ratio to the functional group-containing thermoplastic resin, the functional group of the functional group-containing thermoplastic resin is preferably React with. As a result, it is possible to further reduce the flow of the resin under the chip after the electronic device is embedded and until the thermosetting is completed.

  In the said structure, when the glass transition temperature Tg before hardening of the whole resin sheet is measured, it is preferable that at least 1 glass transition temperature Tg exists in 0 degrees C or less.

  If at least one glass transition temperature Tg exists at 0 ° C. or lower, it can be said that an acrylic resin is contained. If the acrylic resin is contained, the resin can be suitably introduced into the hollow portion between the electronic device and the adherend when the electronic device is embedded.

  The said structure WHEREIN: It is preferable that the said innermost layer does not contain an inorganic filler or contains an inorganic filler in 50 weight% or less with respect to the said innermost layer whole.

  When the content of the inorganic filler in the innermost layer is 50% by weight or less with respect to the entire innermost layer, the followability to the chip is good and stable hollow sealing property can be ensured. If it is 50% by weight or more, even if the molding temperature or pressure is increased, the resin does not enter the gap between the chips without following the chips, and the side surface of the package becomes empty during dicing. May occur.

It is a cross-sectional schematic diagram of the resin sheet which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the electronic device package which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the electronic device package which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the electronic device package which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the electronic device package which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the manufacturing method of the electronic device package which concerns on this embodiment. It is a cross-sectional part enlarged view for demonstrating approach amount X2. (A) is a cross-sectional schematic diagram for demonstrating top | upper surface unevenness | corrugation evaluation, (b) is the top view. It is a cross-sectional schematic diagram for demonstrating top surface unevenness | corrugation evaluation. It is a cross-sectional schematic diagram for demonstrating top surface unevenness | corrugation evaluation. It is a cross-sectional schematic diagram for demonstrating top surface unevenness | corrugation evaluation. It is a cross-sectional schematic diagram for demonstrating top surface unevenness | corrugation evaluation. (A) is a cross-sectional schematic diagram for demonstrating the penetration amount evaluation at the time of a press, (b) is the top view. It is a cross-sectional schematic diagram for demonstrating penetration amount evaluation at the time of a press. It is a cross-sectional schematic diagram for demonstrating penetration amount evaluation at the time of a press. It is a cross-sectional schematic diagram for demonstrating penetration amount evaluation at the time of a press.

  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.

(Resin sheet)
FIG. 1 is a schematic cross-sectional view of an electronic device sealing resin sheet (resin sheet) according to the present embodiment. As shown in FIG. 1, an electronic device sealing resin sheet 11 (hereinafter also referred to as “resin sheet 11”) is typically provided in a state of being laminated on a separator 10 such as a polyethylene terephthalate (PET) film. Is done. The separator 10 may be subjected to a mold release process in order to easily peel the resin sheet 11.

  In addition, although this embodiment demonstrates the case where a separator is laminated | stacked only on one side of the resin sheet, this invention is not limited to this example, The separator may be laminated | stacked on both surfaces of the resin sheet. In this case, one separator can be peeled off immediately before use. In the present invention, the resin sheet may be provided as a single resin sheet without being laminated on the separator. Further, other layers may be laminated on the resin sheet as long as they do not contradict the spirit of the present invention.

  The resin sheet 11 has an outermost layer 11a and an innermost layer 11b laminated on the outermost layer 11a.

  In addition, although this embodiment demonstrates the case where a resin sheet is 2 layer structure of outermost layer and innermost layer, this invention is not limited to this example. In the resin sheet of the present invention, the outermost layer is exposed on one side and the innermost layer is exposed on the other side, and there is another layer between the outermost layer and the innermost layer. Also good.

(Outermost layer)
The outermost layer 11a includes an inorganic filler and a thermoplastic resin.
Content of the said inorganic filler is 85 weight% or more with respect to the outermost layer 11a whole, Preferably, it is 87 weight% or more, More preferably, it is 89 weight% or more. Moreover, although the one where content of the said inorganic filler is large is preferable, from a viewpoint of sheet moldability, it is 93 weight% or less and 90 weight% or less, for example.
The content of the thermoplastic resin is 15% by weight or less, preferably 12% by weight or less, more preferably 8% by weight or less based on the entire resin component of the outermost layer 11a.

The outermost layer 11a contains an inorganic filler in a proportion of 85% by weight or more with respect to the entire outermost layer 11a. Therefore, since it has a certain degree of hardness after curing, the peelability of the electronic device from the dicing tape is improved.
Moreover, the outermost layer 11a can suppress the unevenness | corrugation of the top surface at the time of embedding. This is because the content of the thermoplastic resin in the outermost layer is 15% by weight or less with respect to the entire resin component, so that the top surface is sufficiently smooth due to the low molecular weight components of the epoxy resin and the phenol component. This is because the flow is possible.

  Examples of the thermoplastic resin include 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, heat Plastic 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, fluororesin, styrene-isobutylene-styrene block copolymer, etc. Is 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.

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 outermost layer 11a can be further increased. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.
More specifically, in the present specification, the weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene. As the weight average molecular weight (Mw), a value measured under the following measurement conditions using Tosoh GPC: HLC-8120GPC is adopted.
(Measurement condition)
Column: GMH _XL equivalent x 3 Flow rate: 1.0 ml / min
Detector: RI detector Sample concentration: 0.1 wt% THF solution injection amount: 150 μl

  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 of reacting with the epoxy resin to increase the viscosity and elastic modulus of the outermost layer 11a, it contains at least one of a carboxyl group-containing monomer, a glycidyl group (epoxy group) -containing monomer, and a hydroxyl group-containing monomer. Is preferred.

  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.

The average particle size of the inorganic filler is preferably 20 μm or less, more preferably 0.1 to 15 μm, and more preferably 0.5 to 10 μm. Particularly preferred.
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 polyhedral shape, a polygonal column shape, a flat shape, and an indefinite shape, but a spherical shape is preferable.

The inorganic filler contained in the outermost layer 11a 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 outermost layer 11a is put in a crucible and ignited by igniting at 700 ° C. for 2 hours in an air atmosphere.
(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.
Since the composition of the outermost layer 11a is an organic component other than the inorganic filler, and substantially all the organic components are burned off by the above-described strong heat treatment, the ash content obtained is regarded as the inorganic filler for measurement. The average particle size can be calculated simultaneously with the particle size distribution.

  In the outermost layer 11a, the inorganic filler is preferably surface-treated with a silane coupling agent in advance.

  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 outermost layer 11a contains an inorganic filler surface-treated in advance with a compound having a methacryloxy group or an acryloxy group as a silane coupling agent, the inorganic filler is based on 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 a silane coupling agent.
If the surface treatment of the inorganic filler is performed with a silane coupling agent, the viscosity of the outermost layer 11a can be suppressed from becoming too large.

The outermost layer 11a 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 different kinds of inorganic fillers, it is preferable that at least the inorganic filler having a smaller average particle diameter is surface-treated 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.

  The outermost layer 11a preferably contains 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 outermost layer 11a is preferably 2% by weight or more, and more preferably 3% 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. The hygroscopicity of a resin sheet can be reduced as it is 25 weight% or less.

  The outermost layer 11a preferably contains a curing accelerator.

  The curing accelerator is not particularly limited as long as curing of the epoxy resin and the phenol resin proceeds. For example, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl -S-triazine and the like can be mentioned.

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

  The content of the pigment in the outermost layer 11a 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 may be appropriately added to the resin composition for forming the outermost layer 11a as necessary.

  Although the thickness of the outermost layer 11a is not specifically limited, For example, it is 100-200 micrometers. When it is within the above range, it is possible to mold with a smooth top surface shape with respect to a chip thickness of 100 to 250 μm.

(Innermost layer)
The innermost layer 11b includes a functional group-containing thermoplastic resin.
Content of the said functional group containing thermoplastic resin is 90 weight% or more with respect to the whole resin component of the innermost layer 11b, Preferably it is 93 weight% or more, More preferably, it is 95 weight% or more.
The weight average molecular weight of the functional group-containing thermoplastic resin is 800,000 or more, preferably 1 million or more, and more preferably 1.2 million or more.
The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene. The detailed measurement method is as described above.

The resin sheet 11 is laminated on the electronic device so that the innermost layer 11b is in contact therewith, and then the electronic device is embedded and used.
The innermost layer 11b contains a functional group-containing thermoplastic resin in a proportion of 90% by weight or more with respect to the entire resin component of the innermost layer 11b. Since there are many thermoplastic resin components, resin can be entrapped in the hollow part between an electronic device and a to-be-adhered body at the time of embedding an electronic device.
Moreover, since the said functional group containing thermoplastic resin has a functional group, it bridge | crosslinks after embedding an electronic device until thermosetting is complete | finished. In addition, the functional group-containing thermoplastic resin has a weight average molecular weight of 800,000 or more, and thus hardly flows even when heated. Therefore, the amount of resin entering (moving amount) in the hollow portion between the electronic device and the adherend can be reduced.

  Examples of the functional group-containing thermoplastic resin include a functional group-containing acrylic resin.

  Examples of the functional group-containing acrylic resin include an acrylic resin having a glycidyl group, an amino group, or a plurality of functional groups. Specific examples of the functional group-containing acrylic resin include those having the functional group among the acrylic resins described in the section of the outermost layer 11a. Of these, glycidyl group-containing acrylic resins are preferred. When the glycidyl group-containing acrylic resin is used, it is possible to further reduce the amount of movement of the resin after the electronic device is embedded until the thermosetting is completed.

The innermost layer 11b preferably contains a phenol resin as a curable component.
The phenol resin content is preferably in the range of 0.8 to 2.0 equivalent ratio to the functional group-containing thermoplastic resin, and more preferably in the range of 0.9 to 1.5. More preferably, it is in the range of 1.0 to 1.2.
When the content of the phenol resin contained in the innermost layer 11b is within the range of an equivalent ratio of 0.8 to 2.0 with respect to the functional group-containing thermoplastic resin, the functional group of the functional group-containing thermoplastic resin is preferably used. React with. As a result, it is possible to further reduce the amount of movement of the resin after the electronic device is embedded until the thermosetting is completed.

  As said phenol resin, what was demonstrated by the term of the outermost layer 11a is mentioned.

  The innermost layer 11b preferably does not contain an epoxy resin.

  Even if the innermost layer 11b does not contain or contains an inorganic filler, it is preferable to contain it within a range of 50% by weight or less with respect to the innermost layer 11b. Examples of the inorganic filler include those described in the section of the outermost layer 11a.

  The innermost layer 11b preferably contains a curing accelerator. Examples of the curing accelerator include those described in the section of the outermost layer 11a.

  The innermost layer 11b preferably contains a pigment. Examples of the pigment include those described in the section of the outermost layer 11a.

  In addition to the above components, other additives may be appropriately added to the resin composition for forming the innermost layer 11b as necessary.

  Although the thickness of the innermost layer 11b is not specifically limited, For example, it is 50-100 micrometers. Within the above range, the flow of the outermost layer can be stopped by the innermost layer.

  Although the thickness of the resin sheet 11 whole is not specifically limited, For example, they are 150 micrometers-1000 micrometers. When the thickness is within the above range, a chip having a thickness of 100 to 700 μm can be stably molded.

  The resin sheet 11 preferably has at least one glass transition temperature Tg at 0 ° C. or lower when the glass transition temperature Tg before curing of the entire resin sheet 11 is measured. If at least one glass transition temperature Tg exists at 0 ° C. or lower, it can be said that an acrylic resin is contained. If the acrylic resin is contained, the resin can be suitably introduced into the hollow portion between the electronic device and the adherend when the electronic device is embedded. The glass transition temperature Tg is measured by the method described in the examples.

[Production method of resin sheet]
The resin sheet 11 is obtained by separately producing the outermost layer 11a and the innermost layer 11b and bonding them together.

<Method for producing outermost layer>
The outermost layer 11a was prepared by dissolving and dispersing a resin or the like for forming the outermost layer 11a in an appropriate solvent to adjust the varnish, and coating the varnish on the separator to a predetermined thickness to form a coating film. Thereafter, 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. Examples of the solvent include methyl ethyl ketone, ethyl acetate, toluene and the like.
Further, the outermost layer 11a may be manufactured by kneading extrusion. As a method for producing by kneading extrusion, for example, a kneaded material is prepared by melt kneading each component for forming the outermost layer 11a with a known kneader such as a mixing roll, a pressure kneader, an extruder, etc. Examples thereof include a method of forming the kneaded material into a sheet by plastic processing.
Specifically, the resin sheet can be formed by extrusion molding without cooling the kneaded material after melt-kneading while maintaining a high temperature state. Such an extrusion method is not particularly limited, and examples thereof include a T-die extrusion method, a roll rolling method, a roll kneading method, a co-extrusion method, and a calendar molding method. The extrusion temperature is preferably at least the softening point of each component described above, and is 40 to 150 ° C., preferably 50 to 140 ° C., more preferably 70 to 120 ° C., considering the thermosetting property and moldability of the epoxy resin. is there. Thus, the outermost layer 11a can be formed.

<Method for producing innermost layer>
The innermost layer 11b can be formed by the same method as the outermost layer 11a.

  Moreover, as another manufacturing method of the resin sheet 11, after applying and drying the varnish for forming the outermost layer 11a on the separator to obtain the outermost layer 11a, the innermost layer 11b is formed on the outermost layer 11a. For this purpose, a varnish may be applied and dried.

[Method of manufacturing hollow electronic device package]
The resin sheet of the present invention can be suitably used as an electronic device sealing resin sheet for hollow sealing.
The manufacturing method of the hollow electronic device package according to the present embodiment is as follows:
A step of preparing a laminate in which an electronic device is fixed on an adherend via bumps;
Preparing the resin sheet;
Arranging the resin sheet on the electronic device of the laminate so that the innermost layer is in contact therewith;
A step of embedding the electronic device in the resin sheet by hot pressing;
After the step of embedding, at least a step of thermally curing the resin sheet to obtain a sealing body.

  The adherend is not particularly limited, and examples thereof include a printed wiring board, a ceramic substrate, a silicon substrate, a metal substrate, and a LTCC (Low Temperature Co-fired Ceramics) substrate. In this embodiment, the SAW chip 13 mounted on the printed wiring board 12 is hollow-sealed with the resin sheet 11 to produce a hollow electronic device 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.

  2-6 is a cross-sectional schematic diagram for demonstrating the manufacturing method of the hollow type electronic device package based on this embodiment.

(Process of preparing a laminate)
In the method for manufacturing a hollow electronic device package according to this 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 bumps 13a. 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 resin sheet)
Moreover, in the manufacturing method of the hollow type electronic device package which concerns on this embodiment, the resin sheet 11 (refer FIG. 1) is prepared.

(Process of placing resin sheet)
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 resin sheet 11 is disposed on the surface of the SAW chip 13. To do. At this time, it arrange | positions so that the surface of the SAW chip | tip 13 and the innermost layer 11b of the resin sheet 11 may contact | connect. In this step, the laminated body 15 may be first arranged on the lower heating plate 22, 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 22.

(Process to embed electronic device in resin sheet)
Next, as shown in FIG. 4, the SAW chip 13 is embedded in the resin sheet 11 by hot pressing with the lower heating plate 22 and the upper heating plate 24. The lower heating plate 22 and the upper heating plate 24 may be provided in a flat plate press. The resin sheet 11 functions as a sealing resin for protecting the SAW chip 13 and its accompanying elements from the external environment.

This embedding process is performed so that the amount X2 (see FIG. 7) of the resin constituting the resin sheet 11 entering the hollow portion 14 between the SAW filter 13 and the printed wiring board 12 is 0 μm or more and 20 μm or less. Is preferred. FIG. 7 is a cross-sectional partial enlarged view for explaining the approach amount X2. The entry amount X2 is preferably 0 μm or more and 15 μm or less. The method of setting the ingress amount X2 to 0 μm or more and 20 μm or less can be achieved by adjusting the viscosity of the resin sheet 11 or adjusting hot press conditions. More specifically, for example, there is a method of setting the pressure and the temperature higher.
In addition, when sealing a plurality of SAW filters 13 at a time, “the entry amount X2 is 0 μm or more and 20 μm or less” means that “the entry amount X2 is 0 μm or more and 20 μm or less” for all the SAW filters 13. Means that.

Specifically, the hot press conditions for embedding the SAW chip 13 in the resin sheet 11 vary depending on the viscosity of the resin sheet 11 and the like, but the temperature is preferably 20 to 150 ° C., more preferably 40 to 100 ° C. The pressure is, for example, 0.01 to 20 MPa, preferably 0.05 to 5 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. By setting the hot press condition within the above numerical range, the approach amount X2 can be easily within the numerical range.
If the temperature during hot pressing is too high, the reaction starts during hot pressing and the amount of penetration may vary. From the viewpoint of workability, a low temperature (for example, 100 ° C. or lower) is required. The pressure is also preferably low from the viewpoint of preventing damage to the chip.

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 the pressure reduction conditions, the pressure is, for example, 0 to 20 Torr, preferably 5 to 10 Torr, and the pressure reduction holding time (time from the pressure reduction start to the press start) is, for example, 5 to 600 seconds, preferably 10 to 300 seconds.

(Separator peeling process)
Next, when the resin sheet 11 is used with the separator attached to one side as in this embodiment, the separator 11a is peeled off (see FIG. 5).

(Process to obtain a sealed body by thermosetting)
Next, the sealing body 25 is obtained by thermosetting the resin sheet 11.
In the step of obtaining the sealing body, when the amount of the resin entering the hollow portion 14 in the state after the step of obtaining the sealing body 25 is Y2, the entry amount X2 is subtracted from the entry amount Y2. It is preferable to carry out such that the value is 30 μm or less. The value obtained by subtracting the entry amount X2 from the entry amount Y2 is preferably 25 μm or less. As a method of setting the value obtained by subtracting the entry amount X2 from the entry amount Y2 to be 30 μm or less, the configuration of the resin sheet 11 is adjusted so that the viscosity before curing of the resin sheet 11 is adjusted or the curing rate at the time of heating is increased. This can be achieved by adjusting the material. Specifically, it can be achieved, for example, by selecting the curing accelerator.

Specifically, although the heat curing conditions vary depending on the viscosity, the constituent materials, and the like of the resin sheet 11, 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.
By setting the conditions of the thermosetting treatment within the above numerical range, the flow distance of the resin between the embedding process and after the thermosetting process, that is, the value obtained by subtracting the entry amount X2 from the entry amount Y2 is set to 30 μm or less. easy.

  When only one SAW filter 13 as an electronic device is sealed, the sealing body 25 can be made into one hollow electronic device package. Further, when the plurality of SAW filters 13 are sealed together, each of the SAW filters can be divided into one hollow electronic device package. That is, when the plurality of SAW filters 13 are collectively sealed as in this embodiment, the following configuration may be further performed.

(Dicing process)
You may dice the sealing body 25 after a thermosetting process (refer FIG. 6). Thereby, the hollow package 18 (hollow type electronic device package) in units of the SAW chip 13 can be obtained. Dicing is performed after a dicing tape is attached to the outermost layer 11 a side of the sealing body 25. Since the dicing tape is applied to the outermost layer 11a, the hollow package 18 can be easily peeled off from the dicing tape after dicing.

(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 a resin sheet has been described. However, the present invention is not limited to this example, and the mold release is performed in a vacuum chamber in a vacuum state. After sealing the laminate of the electronic device and the resin sheet with a film, the electronic device may be embedded in the thermosetting resin sheet of the resin sheet by introducing a gas at atmospheric pressure or higher into the chamber. Specifically, the electronic device may be embedded in a thermosetting resin sheet of a resin sheet by a method described in JP2013-52424A.

  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 resin 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 A: 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.)
Thermoplastic resin B: NDHB-101 manufactured by Negami Kogyo Co., Ltd. (glycidyl group-containing acrylate copolymer, weight average molecular weight: about 1 million, glass transition temperature (Tg): -31 ° C.)
Thermoplastic resin C: ND-77L (manufactured by Negami Kogyo Co., Ltd. (glycidyl group-containing acrylate copolymer, weight average molecular weight: about 1.1 million, glass transition temperature (Tg): −10 ° C.)
Thermoplastic resin D: ND-78L manufactured by Negami Kogyo Co., Ltd. (glycidyl group-containing acrylate copolymer, weight average molecular weight: about 1.1 million, glass transition temperature (Tg): −15 ° C.)
Thermoplastic resin E: NDF-001 manufactured by Negami Kogyo Co., Ltd. (glycidyl group-containing acrylate copolymer, weight average molecular weight: about 500,000, glass transition temperature (Tg): 4 ° C.)
Thermoplastic resin F: NDF-002 manufactured by Negami Kogyo Co., Ltd. (glycidyl group-containing acrylate copolymer, weight average molecular weight: about 100,000, glass transition temperature (Tg): 4 ° 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.

[Production of Resin Sheets According to Examples and Comparative Examples]
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 85% by weight. This varnish was applied on a silicone release-treated separator and then dried at 110 ° C. for 5 minutes. As a result, a sheet having a thickness of 55 μm was obtained. This sheet was laminated on each of three upper layers and one lower layer to prepare a resin sheet having a thickness of 220 μm.
In addition, in the following evaluation, it is preferable to implement the thickness of the resin sheet by the thickness more than the sum of the chip thickness and bump height used by the following evaluation. This is because if the sheet thickness is too thin, the amount of intrusion decreases and stable evaluation cannot be performed. Therefore, in this example, it was set to 220 μm, which is the “total of chip thickness and bump height” in the following evaluation.

(Evaluation of top surface unevenness)
FIG. 8A is a schematic cross-sectional view for explaining the top surface unevenness evaluation, and FIG. 8B is a plan view thereof. 9 to 11 are schematic cross-sectional views for explaining the top surface unevenness evaluation. FIG. 12 is a schematic plan view for explaining the top surface unevenness evaluation.

<Step A1>
First, four dummy chips 113 having the following specifications were prepared (see FIGS. 8A and 8B).
[Dummy chip specifications]
Chip size: 3 mm long, 3 mm wide, 200 μm thick
Chip hollow gap: 20 μm (that is, bump height 20 μm)
Material: Silicon wafer Chip: Photosensitive resin bump In recent years, electronic devices have been made thinner and chips and semiconductor packages have been required to be made thinner. Therefore, the bump height formed on the chip surface is required to be about 10 to 50 μm. Here, since the bump is formed on the wafer surface after the silicon wafer is ground to a predetermined thickness, the bump cannot be effectively formed if the wafer thickness is too thin. Therefore, in this example, in consideration of the limit of the wafer thickness where bumps can be stably formed, the evaluation was performed by adopting a chip thickness of about 200 μm. Moreover, in order to suppress the variation in evaluation, the bump height should be low. From this viewpoint, the bump height was evaluated as 20 μm.

<Step B1>
On the substrate 112 (size: length 6 cm, width 10 cm, thickness, 1.3 mm, material: glass), the prepared dummy chips 113 are arranged so that the distance W between adjacent chips is 300 μm (see FIG. 8 (a) and FIG. 8 (b)).

<Step C1>
The resin sheet having a thickness of 220 μm prepared in the above Examples and Comparative Examples was cut into 25 mm length and 25 mm width to obtain Sample 111 (see FIG. 9).

<Step D1>
Sample 111 was placed on dummy chip 113 (see FIG. 10).

<Step E1>
With the separator 110 attached, lamination was performed with a vacuum press at 75 ° C. for 60 seconds and a pressure of 300 kPa (see FIG. 11). Lamination was performed by hot pressing with the lower heating plate 122 and the upper heating plate 124. Then, it heated at 150 degreeC for 1 hour. Thereafter, the separator 1110 was peeled off. In this example, 2PHZ-PW (2-phenyl-4,5-dihydroxymethylimidazole) manufactured by Shikoku Kasei Kogyo Co., Ltd. is used as the curing accelerator, and this product “2PHZ-PW” is the reaction start Since the temperature was around 145 ° C., the heating condition was 150 ° C. for 1 hour.

<Step F1>
The thickness of the portion of the center Y (see FIG. 12) of the sample 111 was measured with a contact-type surface roughness meter in plan view.The case where the dent amount between the chip chips is 30 μm or more with reference to the center of the chip. The case of less than 30 μm was evaluated as ◯, and the results are shown in Table 1.

(Intrusion amount evaluation during press)
Fig.13 (a) is a cross-sectional schematic diagram for demonstrating the penetration amount evaluation at the time of a press, and FIG.13 (b) is the top view. 14-16 is a cross-sectional schematic diagram for demonstrating top | upper surface unevenness | corrugation evaluation.

<Step A2>
First, a dummy chip mounting substrate 215 was prepared in which 25 dummy chips 213 having the following specifications were mounted on a glass substrate 212 (length 6 cm, width 10 cm, thickness 1.3 mm) via resin bumps 213a (FIG. 13 ( a), see FIG. 13B). The gap width between the glass substrate 212 and the dummy chip 213 was 50 μm.
The distance W2 between adjacent chips is 300 μm.
[Dummy chip specifications]
Chip size: 3 mm long, 3 mm wide, 200 μm thick
Bump material: Resin bump (resin material: acrylic resin)
Bump height: 20μm
Number of bumps: 100 bumps
Bump arrangement position: 10 vertical × 10 horizontal, 200 μm pitch Specifically, dummy chip mounting substrate 215 was prepared by mounting dummy chip 213 on glass substrate 212 under the following bonding conditions.
<Bonding conditions>
Equipment: manufactured by Panasonic Electric Works Co., Ltd. Bonding conditions: 200 ° C., 3N, 1 second, ultrasonic output 2W

<Step B2>
The resin sheet having a thickness of 220 μm prepared in the above examples and comparative examples was cut into a length of 3 cm and a width of 3 cm to obtain a sample 211 (see FIG. 14).

<Step C2>
The sample 211 was placed on the dummy chip 213 of the dummy chip mounting substrate 215 (see FIG. 15).

<Step D2>
With the separator 210 attached, the dummy chip 213 was embedded in the sample 211 under the following embedding conditions (see FIG. 16). The embedding was performed by hot pressing with the lower heating plate 222 and the upper heating plate 224.
<Embedding conditions>
Pressing method: Flat plate press Temperature: 75 ° C
Applied pressure: 1500 kPa
Degree of vacuum during pressing: 1.6 kPa
Press time: 1 minute

<Step E2>
After opening to atmospheric pressure, it was left in a hot air dryer at 150 ° C. for 1 hour. Thereby, the said sample was thermosetted and the sealing body sample was obtained. The amount Y1 of the resin constituting the sample 211 into the hollow portion between the dummy chip 213 and the glass substrate 212 of the obtained sealed sample was measured. Specifically, the amount Y1 of the resin entering the hollow portion between the dummy chip 213 and the glass substrate 212 was measured using a product name “Digital Microscope” (200 times) manufactured by KEYENCE. The resin penetration amount Y1 was determined by measuring the maximum reach distance of the resin that entered the hollow portion from the end of the SAW chip, and this was defined as the resin penetration amount Y1. In addition, when there was no entry and the hollow portion spread outside the SAW chip, the resin entry amount was expressed as minus (in this example and the comparative example, there was no minus).
The amount of entry Y1 was measured with the dummy chip 213-1 disposed on the outside and the dummy chip 213-2 disposed on the inside.
The dummy chip 213-1 arranged outside means a dummy chip located at each vertex arranged in a 5 × 5 square. The entry amount Y1 of the dummy chip 213-1 disposed on the outside is an average value of four chips (indicated as the outside entry amount in Table 1).
The dummy chip 213-2 arranged inside is located third from the top (third from the bottom) and third from the left (third from the right) among the chips arranged in a 5 × 5 square. It means a dummy chip. As the approach amount Y1 of the dummy chip 213-2 arranged on the inner side, a measured value of the approach amount Y1 of the one dummy chip 213-2 is adopted (indicated as the inner approach amount in Table 1).
A case where both the inner approach amount and the outer approach amount were 20 μm or less and the difference between the inner approach amount and the outer approach amount was 30 μm or less was evaluated as ◯.
When at least one of the inner approach amount and the outer approach amount was larger than 20 μm, the case where the difference between the inner approach amount and the outer approach amount was larger than 30 μm was evaluated as x.

<Measurement of glass transition temperature Tg before curing of entire sheet>
The glass transition temperature Tg was obtained from the maximum value of the loss tangent (tan δ) measured using a dynamic viscoelasticity measuring device (DMA, frequency 1 Hz, heating rate 10 ° C./min).
Dynamic viscoelasticity measuring device (DMA): trade name “RSAG2”, manufactured by TA Instruments Inc. Mode: Tensile mode Temperature rising rate: 10 ° C./min Frequency: 1 Hz
Sample thickness: 260 μm
Distance between chucks: 20mm
Strain: 0.1%
Measurement temperature range: -50 ° C to 100 ° C

11 Electronic device sealing resin sheet (resin sheet)
13 SAW filter (electronic device)
DESCRIPTION OF SYMBOLS 14 Hollow part 15 Laminated body 18 Hollow type electronic device package 25 Sealing body

Claims (5)

Having an outermost layer and an innermost layer,
The outermost layer includes an inorganic filler and a thermoplastic resin,
The content of the inorganic filler is 85% by weight or more with respect to the entire outermost layer,
The content of the thermoplastic resin is 15% by weight or less based on the entire resin component of the outermost layer,
The innermost layer includes a functional group-containing thermoplastic resin having a weight average molecular weight of 800,000 or more,
Content of the said functional group containing thermoplastic resin is 90 weight% or more with respect to the whole resin component of the said innermost layer, The resin sheet characterized by the above-mentioned.   The resin sheet according to claim 1, wherein the functional group-containing thermoplastic resin is a glycidyl group-containing acrylic resin. The innermost layer includes a phenol resin as a curable component,
3. The resin sheet according to claim 1, wherein a content of the phenol resin is within a range of an equivalent ratio of 0.8 to 2.0 with respect to the functional group-containing thermoplastic resin.   4. The resin sheet according to claim 1, wherein at least one glass transition temperature Tg is present at 0 ° C. or lower when the glass transition temperature Tg before curing of the entire resin sheet is measured. . 5. The resin sheet according to claim 1, wherein the innermost layer does not contain an inorganic filler or contains an inorganic filler in an amount of 1% by weight or less based on the entire innermost layer. .

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