JP2018104649A - Resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin sheet capable of putting a resin to reach an end of a hollow type electronic device when embedding the hollow type electronic device, and preventing the resin from making a large movement at a thermal cure.SOLUTION: A resin sheet includes an inorganic filler. The inorganic filler has a grain diameter of 0.5-45 μm. In the inorganic filler, a specific surface area is within a range of 2.0-4.5 m/g with regard to 50 wt.% or more inorganic filler in the whole inorganic filler.SELECTED DRAWING: Figure 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 and Patent Document 2).

  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.

JP 2006-19714 A JP 2014-189790 A

  When sealing a hollow electronic device by the above-described method, it is necessary that the resin does not enter the hollow portion of the hollow electronic device so that the hollow state is maintained after the sealing resin is cured. .

  As a method for maintaining the hollow state, it is necessary that the resin reaches the end of the hollow electronic device when the hollow electronic device is embedded, and that the resin does not move greatly in the hollow portion during thermosetting.

  In order to allow the resin to reach the end of the hollow electronic device when the hollow electronic device is embedded, the sealing resin needs to have high fluidity at the temperature at the time of embedding. On the other hand, it is necessary to lower the fluidity of the sealing resin during thermosetting so that the resin does not move greatly in the hollow portion during thermosetting.

Conventionally, in order to increase the fluidity of a sealing resin, a method of closely filling an inorganic filler is often employed. For example, a method of densely filling an inorganic filler by incorporating a fine inorganic filler with a small particle diameter in an optimum ratio into the main inorganic filler may be employed.
Also, from the viewpoint of ensuring the reliability of the manufactured hollow electronic device package, a method of densely filling an inorganic filler having a low coefficient of thermal expansion (CTE) may be employed.

  However, if the design is such that the inorganic filler is closely packed, the minimum melt viscosity may be excessively reduced. For this reason, the flow amount of the resin during thermosetting becomes large, and there is a possibility that the resin will greatly enter the hollow portion.

  The present invention has been made in view of the above-described problems. The purpose of the present invention is to allow the resin to reach the end of the hollow electronic device when the hollow electronic device is embedded, and within the hollow portion during thermosetting. It is an object of the present invention to provide a resin sheet that can prevent the resin from moving greatly.

  The inventors of the present application have studied a resin sheet in order to solve the conventional problems. As a result, by adopting the following configuration, when the hollow electronic device is embedded, the resin can reach the end of the hollow electronic device, and during thermosetting, the resin does not move greatly in the hollow portion. As a result, the present invention has been completed.

That is, the resin sheet according to the present invention is
Containing inorganic fillers,
The inorganic filler has a particle size of 0.5 μm or more and 45 μm or less,
The inorganic filler is 50 specific surface area of the weight percent of the inorganic filler of the total inorganic filler is in the range of 2.0m ² /g~4.5m ² / g.

According to the said structure, it contains an inorganic filler and the said inorganic filler exists in the range of a particle size of 0.5 micrometer or more and 45 micrometers or less. That is, the inorganic filler includes only those having a particle diameter of 0.5 μm or more and 45 μm or less, and does not include an inorganic filler having a particle diameter of less than 0.5 μm or an inorganic filler having a particle diameter of more than 45 μm.
Therefore, the inorganic filler is not densely filled.
As a result, when the hollow electronic device is embedded, the resin can reach the end of the hollow electronic device, and at the time of thermosetting, for example, the resin moves greatly in the hollow portion by controlling the minimum melt viscosity. It is possible not to let it.
Moreover, since the inorganic filler with a particle size of less than 0.5 μm is not included, excessive reduction in viscosity can be suppressed. In addition, since the inorganic filler larger than the particle size of 45 μm is not included, it is unlikely that the inorganic filler having a particle size equal to or larger than the bump height is blocked at the end of the hollow electronic device. Therefore, it is possible to prevent only the resin component from flowing into the hollow portion. As a result, the resin can be prevented from excessively entering the hollow portion.
In addition, since the specific surface area of 50% by weight or more of the total inorganic filler is 2.0 m ² / g or more, a viscosity capable of filling the resin to the end of the hollow electronic device is obtained. Can do. Moreover, the dispersion | variation in resin viscosity is suppressed and stable resin can be obtained. On the other hand, since the specific surface area of 50% by weight or more of all inorganic fillers is 4.5 m ² / g or less, the viscosity at which the resin can be filled at least to the end of the hollow electronic device after curing. This resin can be obtained.

  The said structure WHEREIN: It is preferable that content of the said inorganic filler is 75 weight% or more with respect to the whole resin sheet.

  When the content of the inorganic filler is 75% by weight or more with respect to the entire resin sheet, the influence due to the particle size of the inorganic filler being in the range of 0.5 μm or more and 45 μm or less can be increased. . Therefore, the resin can reach the end of the hollow electronic device more preferably at the time of embedding the hollow electronic device, and more preferably, the resin cannot be moved greatly through the hollow portion at the time of thermosetting. Is possible.

  In the above structure, the melt viscosity η at 90 ° C. is preferably 100,000 Pa · s or more and 350,000 Pa · s or less.

  When the melt viscosity η at 90 ° C. is 100000 Pa · s or more, it is possible to prevent the approach amount from becoming excessive. On the other hand, when the melt viscosity η at 90 ° C. is 350,000 Pa · s or less, at least the resin can be filled to the end of the hollow electronic device after thermosetting.

It is a cross-sectional schematic diagram of the resin sheet for electronic device sealing which concerns on this embodiment. It is a cross-sectional schematic diagram for demonstrating the procedure which measures the approach amount X1 and the approach amount Y1. It is a cross-sectional schematic diagram for demonstrating the procedure which measures the approach amount X1 and the approach amount Y1. It is a cross-sectional schematic diagram for demonstrating the procedure which measures the approach amount X1 and the approach amount Y1. It is a cross-sectional schematic diagram for demonstrating the procedure which measures the approach amount X1 and the approach amount Y1. It is the elements on larger scale of FIG. 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.

(Resin sheet for sealing electronic devices)
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 11a such as a polyethylene terephthalate (PET) film. Is done. The separator 11a 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 of the present invention can be suitably used as an electronic device sealing resin sheet for hollow sealing. The resin sheet 11 preferably has an entry amount Y1 measured by the procedure of the following Step A to Step G of 0 μm or more and 80 μm or less. The entry Y1 is more preferably 0 μm or more and 70 μm or less, and further preferably 0 μm or more and 50 μm or less.

Step A for preparing a dummy chip mounting substrate in which one dummy chip having the following specifications is mounted on a glass substrate through a resin bump,
Step B for preparing a sample of a resin sheet having a size of 1 cm in length, 1 cm in width, and thickness of 220 μm,
Placing the sample on the dummy chip of the dummy chip mounting substrate;
Embedding the dummy chip in the sample under the following embedding conditions:
Step E after the step D, measuring the amount X1 of resin that constitutes the sample into the hollow portion between the dummy chip and the glass substrate,
After the step E, it is left in a hot air dryer at 150 ° C. for 1 hour, and the sample is thermally cured to obtain a sealed sample, and F
Step G of measuring an amount Y1 of the resin entering the hollow portion in the sealing body sample.
<Dummy chip specifications>
A resin bump having a chip size of 3 mm in length, 3 mm in width, 200 μm in thickness, and 20 μm in height is formed.
<Embedding conditions>
Press method: Flat plate press Temperature: 65 ° C
Applied pressure: 0.1 MPa
Degree of vacuum: 1.6 kPa
Press time: 1 minute Note that if the temperature of the embedding condition is too low, the adhesion to the glass substrate is reduced, and the penetration amount X1 cannot be clearly observed (the void around the chip is large). The reaction started during hot pressing, and the amount of intrusion may vary (reproducibility decreases), and workability also decreases. The pressure was set to 0.1 MPa from the viewpoint of damage to the chip and adhesion to the glass substrate.

  Hereinafter, an approach amount X1 and a method for obtaining a value obtained by subtracting the approach amount X1 from the approach amount Y1 will be described.

  2-5 is a cross-sectional schematic diagram for demonstrating the procedure which measures the approach amount X1 and the approach amount Y1. FIG. 6 is a partially enlarged view of FIG.

(Step A)
In step A, as shown in FIG. 2, a dummy chip mounting substrate 115 is prepared in which one dummy chip 113 is mounted on the glass substrate 112 via resin bumps 113a. The specifications of the dummy chip 113 are as follows. More specifically, the dummy chip mounting substrate 115 is prepared by the method described in the embodiments.
<Specifications of dummy chip 113>
A resin bump 113a having a chip size of 3 mm in length, 3 mm in width and 200 μm in thickness and 20 μm in height is formed.

(Step B)
In Step B, as shown in FIG. 3, a sample 111 having a size of 1 cm in length, 1 cm in width, and 220 μm in thickness is prepared. Sample 111 is made of the same material as resin sheet 11 and has a size of 1 cm in length, 1 cm in width, and 220 μm in thickness. In the present embodiment, a case where the sample 111 is stacked on the separator 111a will be described. The sample 111 can be prepared by, for example, first creating the sealing sheet 11 having a length of 10 cm or more, a width of 10 cm or more, and a thickness of 220 μm, and then cutting it into a size of 1 cm in length, 1 cm in width, and 220 μm in thickness. it can. The resin sheet 11 itself does not have to be 1 cm in length, 1 cm in width, and 220 μm in thickness.

(Step C)
In step C, as shown in FIG. 4, the sample 111 is placed on the dummy chip 113 of the dummy chip mounting substrate 115. For example, the dummy chip mounting substrate 115 is disposed on the lower heating plate 122 with the surface to which the dummy chip 113 is fixed facing upward, and the sample 111 is disposed on the surface of the dummy chip 113. In this step, the dummy chip mounting substrate 115 may be first disposed on the lower heating plate 122, and then the sample 111 may be disposed on the dummy chip mounting substrate 115, or the sample 111 may be disposed on the dummy chip mounting substrate 115. A laminate in which the dummy chip mounting substrate 115 and the sample 111 are laminated may be disposed on the lower heating plate 122 after being laminated first.

(Step D)
After step C, in step D, as shown in FIG. 5, the dummy chip 113 is embedded in the sample 111 under the following embedding conditions. Specifically, the dummy chip 113 is embedded in the sample 111 by hot pressing with the lower heating plate 122 and the upper heating plate 124 included in the flat plate press under the following embedding conditions. Then, it is left at atmospheric pressure and room temperature (25 ° C.). The leaving time is within 24 hours.
<Embedding conditions>
Press method: Flat plate press Temperature: 65 ° C
Applied pressure: 0.1 MPa
Degree of vacuum: 1.6 kPa
Press time: 1 minute

(Step E)
After step D, in step E, the amount X1 of resin that forms the sample 111 into the hollow portion 114 between the dummy chip 113 and the glass substrate 112 is measured (see FIG. 6). The approach amount X1 is the maximum reach distance of the resin that has entered the hollow portion 114 from the end portion of the dummy chip 113.

(Step F)
After Step E, the structure in which the dummy chip 113 is embedded in the sample 111 is left in a hot air dryer at 150 ° C. for 1 hour, and the sample 111 is thermally cured to obtain a sealed sample.

(Step G)
After the step F, the amount Y1 of the resin entering the hollow portion 114 in the sealing body sample is measured. The amount of entry Y1 is the maximum reachable distance of the resin that has entered the hollow portion 114 from the end of the dummy chip 113.

  Thereafter, a value obtained by subtracting the approach amount X1 from the approach amount Y1 is obtained.

  As described above, the approach amount X1 and the method for obtaining the value obtained by subtracting the approach amount X1 from the approach amount Y1 have been described.

  As described above, the resin sheet 11 has the entry amount Y1 of not less than 0 μm and not more than 80 μm. In a hollow electronic device package, an active surface formed on a bump or an electronic device is often provided at an inner side of 100 μm or more from the end of the electronic device toward the hollow portion. Therefore, when the amount of entry Y1 is 80 μm or less, it is possible to reliably function as a hollow electronic device package.

  A value obtained by subtracting the entry amount X1 from the entry amount Y1, that is, (Y1-X1) is preferably 80 μm or less, and more preferably 50 μm or less.

  When the value obtained by subtracting the entry amount X1 from the entry amount Y1 is 80 μm or less, the flow of the resin in the hollow portion when the resin sheet is thermally cured can be suppressed in the manufacture of an actual hollow electronic device package.

  The entry amount X1 is preferably 10 μm or more and 70 μm or less, and more preferably 0 μm or more and 50 μm or less.

When the penetration amount X1 is not less than 0 μm and not more than 70 μm, when the electronic device is embedded in the resin sheet 11 in the actual manufacturing of the hollow electronic device package, the hollow portion between the electronic device and the adherend is appropriately The resin can be made to enter.
Note that the physical properties of the resin sheet 11 are evaluated using the entry amount Y1, the entry amount X1, and the value obtained by subtracting the entry amount X1 from the entry amount Y1 in the manufacture of an actual hollow electronic device package. This is for evaluation under the assumed conditions. However, the conditions in these evaluations may naturally differ from the conditions in the actual manufacturing of the hollow electronic device package.

  The resin sheet 11 preferably has a melt viscosity η at 90 ° C. of 100000 Pa · s or more and 350,000 Pa · s or less, more preferably 125000 Pa · s or more and 325000 Pa · s or less, and further preferably 150,000 Pa · s or more. 300,000 Pa · s or less.

When the melt viscosity η at 90 ° C. is 100000 Pa · s or more, it is possible to prevent the approach amount from becoming excessive. On the other hand, when the melt viscosity η at 90 ° C. is 350,000 Pa · s or less, at least the resin can be filled to the end of the hollow electronic device after thermosetting.
As a method of controlling the melt viscosity η at 90 ° C. of the resin sheet 11, a method of controlling by the particle size and content of the following inorganic filler, a method of controlling by the type and content of the thermoplastic resin, the resin sheet 11 The method of controlling by the stirring conditions at the time of preparation of the varnish for kneading or kneaded material, etc. are mentioned.

The resin sheet 11 includes an inorganic filler, and the inorganic filler has a particle size in the range of 0.5 μm to 45 μm. The particle diameter is preferably in the range of 0.6 μm to 40 μm, and more preferably in the range of 0.7 μm to 38 μm.
That is, the inorganic filler includes only those having a particle size within a predetermined range, and does not include an inorganic filler having a particle size smaller than the predetermined particle size or an inorganic filler having a particle size larger than the predetermined particle size.
Therefore, the inorganic filler is not densely filled.
As a result, when the hollow electronic device is embedded, the resin can reach the end of the hollow electronic device, and at the time of thermosetting, for example, the resin moves greatly in the hollow portion by controlling the minimum melt viscosity. It is possible not to let it.
Moreover, since it does not contain an inorganic filler having a particle size less than a predetermined particle size, excessive reduction in viscosity can be suppressed. Further, since the inorganic filler larger than the predetermined particle size is not included, the possibility that the inorganic filler having a particle size equal to or larger than the bump height is blocked at the end of the hollow electronic device is low. Therefore, it is possible to prevent only the resin component from flowing into the hollow portion. As a result, the resin can be prevented from excessively entering the hollow portion.
As a method for obtaining an inorganic filler having a particle size in the range of 0.5 μm or more and 45 μm or less, for example, a commercially available inorganic filler is classified, and the inorganic filler having a particle size outside the predetermined range is removed. The method which makes only the inside is mentioned.

  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 content of the inorganic filler is preferably 75% by weight or more and more preferably 80% by weight or more with respect to the entire resin sheet 11.

  When the content of the inorganic filler is 75% by weight or more with respect to the entire resin sheet 11, it is possible to increase the influence of setting the particle size of the inorganic filler within a predetermined range. Therefore, the resin can reach the end of the hollow electronic device more preferably at the time of embedding the hollow electronic device, and more preferably, the resin cannot be moved greatly through the hollow portion at the time of thermosetting. Is possible.

  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.

Specifically, the particle size and particle size distribution of the inorganic filler contained in the resin sheet 11 are obtained by the following method.
(A) The resin sheet 11 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.
In addition, since it is an organic component other than an inorganic filler as a composition of the resin sheet 11 and substantially all the organic components are burned away by the above-mentioned strong heat treatment, the ash content obtained is regarded as an inorganic filler and measured. The average particle size can be calculated simultaneously with the particle size distribution.

  The resin 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 resin 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 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 resin sheet 11 can be suppressed from becoming too large.

The inorganic filler is 50 specific surface area of the weight percent of the inorganic filler of the total mineral filler is in the range of 2.0m ² /g~4.5m ² / g, preferably, 2.1 m ^It exists in the range of ² / g-4.3m < ² > / g. Since the specific surface area of 50% by weight or more of all inorganic fillers is 2.0 m ² / g or more, it is possible to obtain a viscosity capable of filling the resin to the end of the hollow electronic device. . Moreover, the dispersion | variation in resin viscosity is suppressed and stable resin can be obtained. On the other hand, since the specific surface area of 50% by weight or more of all inorganic fillers is 4.5 m ² / g or less, the viscosity at which the resin can be filled at least to the end of the hollow electronic device after curing. This resin can be obtained. The method for measuring the specific surface area of the inorganic filler is based on the method described in Examples.

  The resin sheet 11 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 resin 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. The hygroscopicity of a resin sheet can be reduced as it is 25 weight% or less.

  The resin sheet 11 preferably contains a thermoplastic resin. Thereby, the heat resistance of the resin sheet obtained, 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 resin 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. Especially, it is preferable to include at least one of a carboxyl group-containing monomer, a glycidyl group (epoxy group) -containing monomer, and a hydroxyl group-containing monomer from the viewpoint of increasing the viscosity of the resin sheet 11 by reacting with the epoxy resin.

  0.5 weight% or more is preferable and, as for content of the thermoplastic resin in the resin sheet 11, 1.0 weight% or more is more preferable. When the content is 0.5% by weight or more, the flexibility and flexibility of the resin sheet can be obtained. The content of the thermoplastic resin in the resin sheet 11 is preferably 10% by weight or less, and more preferably 5% by weight or less. When it is 10% by weight or less, the adhesiveness of the resin sheet to the electronic device or the substrate is good.

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

  The curing accelerator is not particularly limited as long as it cures the epoxy resin and the phenol resin, 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. Among the imidazole compounds, 2-phenyl-4-methyl-5-hydroxymethylimidazole is preferable in that the viscosity increase at the time of thermosetting can be accelerated.

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

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

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

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

  Although the thickness of the resin sheet 11 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 resin sheet 11 may have a single layer structure or a multilayer structure in which two or more resin sheets are laminated.

[Production method of resin sheet]
The resin sheet 11 is prepared by dissolving and dispersing a resin or the like for forming the resin sheet 11 in an appropriate solvent to adjust the varnish, and coating the varnish on the separator 11a to a predetermined thickness to form a coating film. Then, the coating film can be formed by drying under predetermined conditions. 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, the resin sheet 11 may be formed by applying the varnish on a support to form a coating film and then drying the coating film under the drying conditions. Then, when the resin sheet 11 that bonds the resin sheet 11 together with the support on the separator 11a includes a thermoplastic resin (acrylic resin), an epoxy resin, and a phenol resin, all of these are dissolved in a solvent, Apply and dry. Examples of the solvent include methyl ethyl ketone, ethyl acetate, toluene and the like.
The resin sheet 11 may be manufactured by kneading extrusion. As a method for producing by kneading extrusion, for example, a kneaded product is prepared by melt kneading each component for forming the resin sheet 11 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 resin sheet 11 can be formed.

[Method of manufacturing hollow electronic device package]
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;
A step of preparing a resin sheet;
Arranging the resin sheet on the electronic device of the laminate;
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 an LTCC (Low Temperature Co-fired Ceramics) substrate, a printed wiring board, a ceramic substrate, a silicon substrate, and a metal substrate. In this embodiment, the SAW chip 13 mounted on the LTCC substrate 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.

  7 to 11 are schematic cross-sectional views for explaining the method for manufacturing the hollow electronic device package according to this embodiment.

(Process of preparing a laminate)
In the method for manufacturing a hollow 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. 7). 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. 8, the laminate 15 is disposed on the lower heating plate 22 with the surface on which the SAW chip 13 is fixed facing up, and the resin sheet 11 is disposed on the surface of the SAW chip 13. To do. 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 of embedding electronic devices in resin sheets for electronic devices)
Next, as shown in FIG. 9, 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 step is preferably performed so that the amount X2 of the resin constituting the resin sheet 11 enters the hollow portion 14 between the SAW filter 13 and the printed wiring board 12 is 0 μm or more and 50 μm or less. The entry amount X2 is more preferably 0 μm or more and 30 μm or less, and further preferably 0 μm or more and 20 μm or less. The method of setting the ingress amount X2 to 0 μm or more and 50 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.

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, 0.1 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, 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. 10).

(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 60 μm or less. The value obtained by subtracting the entry amount X2 from the entry amount Y2 is more preferably 30 μm or less, and even more preferably 10 μm or less. As a method of setting the value obtained by subtracting the entry amount X2 from the entry amount Y2 to 60 μm or less, the resin sheet 11 is configured so that the viscosity before curing of the resin sheet 11 is adjusted or the curing rate during heating is increased. This can be achieved by adjusting the material.

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 from the embedding step to after the thermosetting step, that is, the value obtained by subtracting the entry amount X2 from the entry amount Y2 is within a predetermined range. Easy to be inside.

  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.

(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.
In embodiment mentioned above, the case where the resin sheet of this invention was an object for hollow sealing was demonstrated. However, the resin sheet of the present invention may be a sheet for sealing other than for hollow sealing (for example, a resin sheet used in a mode for sealing a hollow part).

  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: ME-2006M manufactured by Negami Kogyo Co., Ltd. (carboxyl group-containing acrylic ester polymer, weight average molecular weight: about 600,000, acid value: 31 mg KOH / g, polymer concentration 20% methyl ethyl ketone solution)
Inorganic filler A-1: FB-8SM manufactured by Denka Co., Ltd. (silica, average particle size: 5 μm, surface treatment pear, including only particles having a particle size of 0.1 μm to 50 μm (particles having a particle size larger than 50 μm and particles) (Not including those with a diameter of less than 0.1 μm), specific surface area: 2.5)
Inorganic filler A-2: FB-8SM manufactured by Denka Co., Ltd. (silica, average particle size: 5 μm, surface treatment pear, including only particles having a particle size of 0.1 μm to 50 μm (particles larger than 50 μm and particles) (Not including those having a diameter of less than 0.1 μm), specific surface area: 2.7)
Inorganic filler A-3: FB-8SM manufactured by Denka Co., Ltd. (silica, average particle size: 5 μm, surface treatment pear, including only particles having a particle size of 0.1 μm to 50 μm (particles having a particle size larger than 50 μm (Not including those with a diameter of less than 0.1 μm), specific surface area: 1.8)
Inorganic filler A-4: FB-8SM manufactured by Denka Co., Ltd. (silica, average particle size: 5 μm, surface treatment pear, including only particles having a particle size of 0.1 μm to 50 μm (particle size larger than 50 μm and particles) Not including those having a diameter of less than 0.1 μm), specific surface area: 4.3)
Inorganic filler B: SC-220G-SMJ (including silica, those having an average particle size of 0.5 μm, a particle size of larger than 50 μm, and a particle size of less than 0.001 μm) manufactured by Admatechs Co., Ltd. 3-methacryloxy Surface treated with propyltrimethoxysilane (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
Silane coupling agent (epoxy silane coupling agent): KBM-403 (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Silicone
Curing accelerator: HC-188W manufactured by Nippon Shokubai Co., Ltd. (latent effect catalyst in which imidazole catalyst 2P4MHZ is included with 5-hydroxy-isophthalic acid. 2P4MHZ content ratio 67%)

[Production of Resin Sheets According to Examples and Comparative Examples]
According to the mixing ratio of the resin sheet 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 75% 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. Four layers of this sheet were laminated to produce 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 resin penetration into package hollow)
<Step A>
First, a dummy chip mounting substrate was prepared in which one dummy chip having the following specifications was mounted on a glass substrate (length 76 mm, width 26 mm, thickness 1.0 mm) via resin bumps. The gap width between the glass substrate and the dummy chip was 20 μm.
<Dummy chip specifications>
A resin bump (resin material: dry film resist) having a chip size of 3 mm in length, 3 mm in width, and 200 μm in thickness and 20 μm in height is formed. The number of bumps is 63, and is arranged in a predetermined pattern (a pattern in which seven bumps are arranged in an area of 1 mm × 1 mm, and there is a portion that is not equally spaced). The material of the dummy chip is a silicon wafer.
In recent years, electronic devices have been made thinner, and there is a demand for thinner chips and semiconductor packages. 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.

Specifically, the dummy chip mounting substrate was prepared by mounting the dummy chip on the glass substrate 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 B>
A 220 μm thick resin sheet prepared in the above Examples and Comparative Examples was cut into 1 cm length and 1 cm width to make a sample.

<Step C>
The sample was placed on the dummy chip of the dummy chip mounting substrate.

<Step D>
The dummy chip was embedded in the sample under the following embedding conditions.
<Embedding conditions>
Press method: Flat plate press Temperature: 65 ° C
Applied pressure: 0.1 MPa
Degree of vacuum: 1.6 kPa
Press time: 1 minute

<Step E>
After opening to atmospheric pressure, the amount X1 of resin that constitutes the sample into the hollow portion between the dummy chip and the glass substrate was measured. Specifically, the amount X1 of the resin entering the hollow portion between the dummy chip and the ceramic substrate was measured by a trade name “Digital Microscope VHX-2000” (200 times) manufactured by KEYENCE. The resin ingress amount X1 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 ingress amount X1. In addition, when there was no entry and the hollow portion spread outside the SAW chip, the resin entry amount was expressed as minus.

<Step F>
After Step E, 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. In this example, as a curing accelerator, HC-188W manufactured by Nippon Shokubai Co., Ltd. (latent curing catalyst in which imidazole catalyst 2P4MHZ is included with 5-hydroxy-isophthalic acid. 2P4MHZ content ratio 67%) is used. In consideration of the reaction start temperature of this product, the heating condition was set to 150 ° C. for 1 hour in this example.

<Step G>
Thereafter, the amount Y1 of the resin entering the hollow portion in the sealed sample was measured. The measuring method is the same as the approach amount X1. The case where the resin penetration amount Y1 was 0 μm to 80 μm was evaluated as “◯”, and the case where the resin penetration amount Y1 was less than 0 μm or greater than 80 μm was evaluated as “X”. The results are shown in Table 1.

  Thereafter, a value obtained by subtracting the approach amount X1 from the approach amount Y1 was obtained. The results are shown in Table 1. The case where the value obtained by subtracting the approach amount X1 from the approach amount Y1 was 100 μm or less was evaluated as “◯”, and the case where the value was larger than 100 μm was evaluated as “X”. The results are shown in Table 1.

(Measurement of melt viscosity η of resin sheet at 90 ° C.)
The melt viscosity η at 90 ° C. of the resin sheets produced in Examples and Comparative Examples was measured by a parallel plate method using a rheometer (HAAKE II, MARS II). More specifically, the measurement was performed under the following conditions. The lowest viscosity at 90 ° C. measurement was defined as the melt viscosity η. The results are shown in Table 1.
<Measurement conditions>
Measurement mode: After raising the temperature from room temperature (25 ° C.) to 90 ° C., isothermal maintaining at 90 ° C. for 15 minutes Temperature rising rate: 10 ° C./min
Strain amount: 0.05%
Frequency: 1Hz
Sample diameter: 8mmφ

(Measurement of specific surface area of inorganic filler)
The resin sheet was put in a crucible and ignited by igniting at 700 ° C. for 2 hours in an air atmosphere. In addition, since it is an organic component other than an inorganic filler as a composition of a resin sheet and substantially all the organic components are burned down by said strong heat processing, it measured by considering the obtained ash as an inorganic filler.
The BET specific surface area was measured by the BET adsorption method (multipoint method). Specifically, using a quadrant specific surface area / pore distribution measuring device “NOVA-4200e type” manufactured by Quantachrome, the obtained ash was vacuum degassed at 110 ° C. for 6 hours or more, and then in nitrogen gas at 77.35K. Measured at a temperature of. The results are shown in Table 1.

11 Resin sheet for electronic devices (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 112 Glass substrate 113 Dummy chip 113a Resin bump 114 Hollow part 115 Dummy chip mounting board

Claims (3)

Containing inorganic fillers,
The inorganic filler has a particle size of 0.5 μm or more and 45 μm or less,
The inorganic filler, a resin sheet, wherein the 50 specific surface area of the weight percent of the inorganic filler of the total inorganic filler is in the range of 2.0m ² /g~4.5m ² / g .   2. The resin sheet according to claim 1, wherein the content of the inorganic filler is 75% by weight or more based on the entire resin sheet. The resin sheet according to claim 1, wherein the melt viscosity η at 90 ° C. is 100000 Pa · s or more and 350,000 Pa · s or less.

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