JP6497998B2 - Manufacturing method of sealing sheet and package - Google Patents

Description

  The present invention relates to a sealing sheet and a package.

A sheet having a tensile modulus of elasticity of 1 × 10 ⁷ to 1 × 10 ⁹ Pa at 25 ° C. after thermosetting is known (for example, see Patent Document 1).

JP 2009-91389 A

  As shown in FIGS. 17 and 18, the device mounting body 502 and the laminate 531 having the sheet-like thermosetting composition 511 disposed on the device mounting body 502 are pressed to be mounted on the substrate 522 and the substrate 522. The package can be manufactured by a method including a step of forming the sealed body 532 having the thermosetting composition 511 covering the electronic device 523 and the electronic device 523, a step of heating the sealed body 532, and the like. The device mounting body 502 includes a substrate 522 and an electronic device 523 mounted on the substrate 522.

  Since the cured product formed by curing the thermosetting composition 511 after the step of curing the thermosetting composition 511 is thermally contracted, the substrate 522 may be warped. The warp of the substrate 522 causes a conveyance failure.

  As a technique for reducing the warpage of the substrate 522, there is a technique for increasing the content of the inorganic filler in the thermosetting composition 511 so that the linear expansion coefficient of the cured product approaches the linear expansion coefficient of the substrate 522. However, since the storage elastic modulus of the cured product is increased by increasing the content of the inorganic filler, the substrate 522 may still be warped.

  This invention is made | formed in view of the subject mentioned above, The objective is to provide the sheet | seat for sealing which can reduce the curvature of a board | substrate. Moreover, the objective of this invention is providing the manufacturing method of the package which can reduce the curvature of a board | substrate.

The present invention relates to a sealing sheet. The sealing sheet includes a thermosetting composition that forms a sheet. The thermosetting composition includes an inorganic filler and a remaining component. The remaining component includes an acrylic polymer. The content of the acrylic polymer in the remaining components is 65% by weight or more. Content of the inorganic filler in a thermosetting composition is 55 volume% or more. The storage elastic modulus at 25 ° C. of the cured product obtained by curing the thermosetting composition is 5 × 10 ⁷ Pa to 5 × 10 ⁹ Pa.

The content of the acrylic polymer in the remaining components is 65% by weight or more, and the content of the inorganic filler in the thermosetting composition is 55% by volume or more, so that it can be obtained by curing the thermosetting composition. The storage elastic modulus of the cured product at 25 ° C. can be 5 × 10 ⁹ Pa or less, and the linear expansion coefficient of the cured product can be brought close to the linear expansion coefficient of the substrate. Accordingly, the warpage of the substrate can be effectively reduced.

  The present invention also relates to a method for manufacturing a package including a step of pressing a device mounting body and a laminate including a thermosetting composition disposed on the device mounting body. A device mounting body includes a substrate and an electronic device mounted on the substrate.

2 is a schematic cross-sectional view of a sealing sheet according to Embodiment 1. FIG. It is a TEM observation image of the section of hardened material. The lower observation image is a partially enlarged image of the upper observation image. It is an AFM phase image of a section of hardened material. In order to clearly show the sea-island structure, a cured product obtained by curing a thermosetting composition having an epoxy resin, a phenol resin, an acrylic polymer, and a curing accelerator and not having a filler and a pigment was observed. It is a TEM observation image of the section of hardened material. In order to clearly show the sea-island structure, a cured product obtained by curing a thermosetting composition having an epoxy resin, a phenol resin, an acrylic polymer, and a curing accelerator and not having a filler and a pigment was observed. It is schematic sectional drawing, such as a laminated body. It is a schematic sectional drawing of the process of hot-pressing a laminated body. It is a schematic sectional drawing of a structure. It is a schematic sectional drawing of a package. It is a schematic sectional drawing of a SAW filter manufacturing process. It is a schematic sectional drawing of a SAW filter manufacturing process. It is a schematic sectional drawing of a SAW filter manufacturing process. It is a schematic sectional drawing of a SAW filter manufacturing process. It is a schematic sectional drawing of a SAW filter manufacturing process. 6 is a schematic cross-sectional view of a sealing sheet according to Modification Example 1. FIG. It is a front schematic diagram of a layered product for a test. It is a front schematic diagram of a layered product for a test. It is a schematic sectional drawing of a package manufacturing process. It is a schematic sectional drawing of a package manufacturing process.

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

[Embodiment 1]
(Sealing sheet 1)
The sealing sheet 1 will be described.

  As shown in FIG. 1, the sheet | seat 1 for sealing is equipped with the thermosetting composition 11 which makes a sheet form. The sealing sheet 1 further includes a separator 12. Specifically, the sealing sheet 1 includes a separator 12 and a thermosetting composition 11 disposed on the separator 12. Examples of the separator 12 include a polyethylene terephthalate (PET) film. The separator 12 is preferably subjected to a mold release treatment.

  The thermosetting composition 11 includes an inorganic filler and a remaining component.

  Examples of the remaining component include a resin component, a curing accelerator, and a pigment.

  Examples of the resin component include acrylic polymers and thermosetting resins.

  In the thermosetting composition 11, the acrylic polymer and the thermosetting resin are preferably compatible. When they are compatible, the segregation of the thermosetting resin and the segregation of the acrylic polymer do not occur, so that the warpage of the substrate can be reduced. In addition, the acrylic polymer and the thermosetting resin are compatible with each other in the observation image observed with a transmission electron microscope (TEM) that the phase separation structure of the acrylic polymer and the thermosetting resin is not observed. Say.

  An acrylic polymer is preferred because it is easy to obtain flexibility and has good dispersibility with an epoxy resin. Of these, thermoplastic acrylic polymers are preferred.

  The acrylic polymer is not particularly limited, and one or more esters of acrylic acid or methacrylic acid ester having a linear or branched alkyl group having 30 or less carbon atoms, particularly 4 to 18 carbon atoms, are components. And a polymer (acrylic copolymer). Examples of the alkyl group include 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-ethylhexyl. Group, octyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, lauryl group, tridecyl group, tetradecyl group, stearyl group, octadecyl group or dodecyl group.

  Further, 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 monomer, acid anhydride monomer such as maleic anhydride or itaconic anhydride, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxy (meth) acrylate Butyl, 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 of the thermosetting composition 11, 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 acrylic polymer preferably has a functional group. As a functional group, a carboxyl group (—COOH), an epoxy group, a hydroxyl group, an amino group, and a mercapto group are preferable, and a carboxyl group is more preferable because a sea-island structure can be easily formed.

The acid value of the acrylic polymer is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, and further preferably 10 mgKOH / g or more. A domain part can be made small as it is 1 mgKOH / g or more, and the flow of the thermosetting composition 11 can be controlled. On the other hand, the acid value of the acrylic polymer is preferably 100 mgKOH / g or less, more preferably 60 mgKOH / g or less, still more preferably 50 mgKOH / g or less, and particularly preferably 40 mgKOH / g or less. The storage stability of the thermosetting composition 11 can be kept comparatively favorable as it is 100 mgKOH / g or less.
In addition, an acid value can be measured by the neutralization titration method prescribed | regulated to JISK0070-1992.

The weight average molecular weight of the acrylic polymer is preferably 400,000 or more, more preferably 500,000 or more. When it is 400,000 or more, the viscosity of the acrylic polymer is not too low, so that handling is easy. On the other hand, the weight average molecular weight of the acrylic polymer is preferably 2 million or less, more preferably 1.5 million or less. When it is 2 million or less, the viscosity of the acrylic polymer is not too high, so that it is easy to handle.
The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

  The Tg of the acrylic polymer is preferably −70 ° C. or higher, more preferably −60 ° C. or higher, and further preferably −50 ° C. or higher. When the temperature is −70 ° C. or higher, the storage elastic modulus of the thermosetting composition 11 at the molding temperature is not too low, so that the flow of the thermosetting composition 11 can be easily controlled. On the other hand, the Tg of the acrylic polymer is preferably 20 ° C. or lower, more preferably 0 ° C. or lower. When the temperature is 20 ° C. or lower, the storage elastic modulus of the thermosetting composition 11 at the molding temperature is not too high, so that the flow of the thermosetting composition 11 can be easily controlled.

In this specification, the glass transition temperature of an acrylic polymer means the theoretical value calculated | required by the Fox formula.
As another method for obtaining the glass transition temperature, there is a method for obtaining the glass transition temperature of the acrylic polymer from the temperature at the maximum heat absorption peak measured by a differential scanning calorimeter (DSC). Specifically, using a differential scanning calorimeter (“Q-2000” manufactured by TA Instruments Inc.), the sample to be measured is about 50 ° C. higher than the predicted glass transition temperature (predicted temperature) of the sample. After heating at a temperature for 10 minutes, the sample is cooled to a temperature lower by 50 ° C. than the predicted temperature, pre-treated, and then heated at a rate of temperature increase of 5 ° C./min in a nitrogen atmosphere to measure the endothermic start point temperature, This is the glass transition temperature.

  The content of the acrylic polymer in the remaining components is 65% by weight or more. Preferably it is 70 weight% or more, More preferably, it is 75 weight% or more. On the other hand, the content of the acrylic polymer in the remaining component is preferably 95% by weight or less, more preferably 90% by weight or less.

  Although it does not specifically limit as a thermosetting resin, An epoxy resin and a phenol resin are preferable.

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

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

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

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

  The content of the thermosetting resin in the remaining components is preferably 10% by weight or more, more preferably 15% by weight or more, still more preferably 17% by weight or more, and particularly preferably 20% by weight or more. On the other hand, the content of the thermosetting resin in the remaining components is preferably 55% by weight or less, more preferably 45% by weight or less, still more preferably 30% by weight or less, and particularly preferably 25% by weight or less.

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

  Among them, an imidazole-based curing accelerator is preferable because it has a good curing acceleration ability and a cured product having a high Tg can be obtained, and includes 2-phenyl-4,5-dihydroxymethylimidazole, 2,4-diamino-6- [ 2'-ethyl-4'-methylimidazolyl- (1 ')]-ethyl-s-triazine is more preferred, and 2-phenyl-4,5-dihydroxymethylimidazole is more preferred.

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

  The pigment is not particularly limited, and examples thereof include carbon black.

  Examples of the inorganic filler include quartz glass, talc, silica (such as fused silica and crystalline silica), alumina (aluminum oxide), boron nitride, aluminum nitride, and silicon carbide. Among these, silica is preferable because the thermal expansion coefficient can be satisfactorily reduced. Silica is preferably fused silica and more preferably spherical fused silica because it is excellent in fluidity. In addition, a thermally conductive filler is preferable because of its high thermal conductivity, and alumina, boron nitride, and aluminum nitride are more preferable. In addition, as an inorganic filler, an electrically insulating thing is preferable.

  Silica, alumina or the like may be used in combination as the inorganic filler.

The average particle diameter of the inorganic filler is preferably 0.5 μm or more, more preferably 1 μm or more. When the thickness is 0.5 μm or more, it is easy to obtain flexibility and softness of the thermosetting composition 11. The average particle size of the filler is preferably 30 μm or less, more preferably 10 μm or less. When it is 30 μm or less, it is easy to highly fill the filler.
The average particle size can be derived by, for example, using a sample arbitrarily extracted from the population and measuring it using a laser diffraction / scattering particle size distribution measuring apparatus.

  As the inorganic filler, it is preferable to use a surface-treated inorganic filler pretreated with a silane coupling agent. Thereby, the wettability with respect to the resin component of an inorganic filler can be improved, and the dispersibility of an inorganic filler can be improved. As the inorganic filler, it is preferable to use an untreated inorganic filler that has not been previously treated with a surface-treated inorganic filler and a silane coupling agent.

  As the silane coupling agent, for example, a compound having a methacryloxy group or an acryloxy group can be suitably used. The methacryloxy group and acryloxy group are non-reactive with the thermosetting resin. By using a compound having a methacryloxy group or an acryloxy group as a silane coupling agent, an increase in the minimum viscosity of the thermosetting composition 11 due to the reaction between the silane coupling agent and the thermosetting resin can be suppressed.

  The compound having a methacryloxy group or an acryloxy group preferably further has an alkoxy group having 1 to 6 carbon atoms. Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group and an ethoxy group.

  Examples of the compound having a methacryloxy group or an acryloxy group 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.

  It is preferable that at least peak A and peak B exist in the particle size distribution of the inorganic filler. Specifically, it is preferable that the peak A exists in a particle size range of 0.01 μm to 10 μm and the peak B exists in a particle size range of 1 μm to 100 μm. Since the inorganic filler forming the peak A can be filled between the inorganic fillers forming the peak B, the inorganic filler can be highly filled.

  More preferably, the peak A exists in a particle size range of 0.1 μm or more. More preferably, the peak A exists in a particle size range of 1 μm or less.

  More preferably, the peak B exists in a particle size range of 3 μm or more. More preferably, the peak B exists in a particle size range of 10 μm or less.

  In the particle size distribution of the inorganic filler, there may be a peak C other than the peak A and the peak B.

  The particle size distribution of the inorganic filler can be measured by the following method.

Method for Measuring Particle Size Distribution of Inorganic Filler Thermosetting composition 11 is placed in a crucible and ignited to incinerate thermosetting composition 11. The obtained ash was dispersed in pure water and subjected to ultrasonic treatment for 10 minutes, and the particle size distribution (volume basis) using a laser diffraction / scattering particle size distribution analyzer (“LS 13 320” manufactured by Beckman Coulter, Inc .; wet method). )

  Content of the inorganic filler in the thermosetting composition 11 is 55 volume% or more, More preferably, it is 60 volume% or more, More preferably, it is 70 volume% or more. By increasing the content of the inorganic filler, it is possible to bring the linear expansion coefficient of the cured product closer to the linear expansion coefficient of the substrate. On the other hand, the content of the inorganic filler in the thermosetting composition 11 is preferably 85% by volume or less, more preferably 80% by volume or less. It is easy to shape | mold into a sheet form as it is 85 volume% or less.

The content of the inorganic filler can be explained by using “wt%” as a unit. Typically, the content of silica will be described in units of “% by weight”.
Since the specific gravity of silica is usually 2.2 g / cm ³ , the preferred range of the silica content (% by weight) is, for example, as follows.
That is, the content of silica in the thermosetting composition 11 is preferably 60% by weight or more, more preferably 70% by weight or more, and further preferably 80% by weight or more. On the other hand, the content of silica in the thermosetting composition 11 is preferably 90% by weight or less, more preferably 85% by weight or less.

Since the specific gravity of alumina is usually 3.9 g / cm ³ , the preferred range of the alumina content (% by weight) is, for example, as follows.
That is, the content of alumina in the thermosetting composition 11 is preferably 72% by weight or more, more preferably 80% by weight or more, and still more preferably 87% by weight or more. On the other hand, the content of alumina in the thermosetting composition 11 is preferably 95% by weight or less, more preferably 93% by weight or less.

The storage elastic modulus in 25 degreeC of the hardened | cured material obtained by hardening the thermosetting composition 11 is 5 * 10 < ⁷ > Pa-5 * 10 < ⁹ > Pa. By being 5 × 10 ⁹ Pa or less, it is possible to reduce the stress generated by returning the cured product to room temperature, and the warpage of the substrate can be reduced. Further, the warpage of the substrate caused by reflow heating can be reduced. An electronic device can be favorably sealed by being 5 × 10 ⁷ Pa or more.

The storage elastic modulus of the cured product at 25 ° C. is preferably 9 × 10 ⁷ Pa or more. On the other hand, the storage elastic modulus at 25 ° C. of the cured product is preferably 1 × 10 ⁹ Pa or less, more preferably 5 × 10 ⁸ Pa or less.
The storage elastic modulus can be measured by the method described in the examples.

  The storage elastic modulus of the cured product can be controlled by the content of acrylic polymer, the content of inorganic filler, and the like.

The glass transition temperature (Tg) of the cured product is preferably 100 ° C. or higher, more preferably 120 ° C. or higher. The Tg of the cured product is preferably 200 ° C. or lower, more preferably 170 ° C. or lower.
Tg can be measured by the method described in the examples.

  The Tg of the cured product can be controlled by the crosslinking density. For example, Tg can be increased by using a thermosetting resin having a large number of functional groups in the molecule.

The linear expansion coefficient (CTE1) at Tg or less of the cured product is preferably 20 ppm / K or less, more preferably 17 ppm / K or less. When it is 20 ppm / K or less, the warpage of the substrate can be effectively reduced. On the other hand, the lower limit of CTE1 of the cured product is not particularly limited. For example, CTE1 of hardened | cured material is 5 ppm / K or more, 8 ppm / K or more.
The linear expansion coefficient can be measured by the method described in the examples.

  The cured product obtained by curing the thermosetting composition 11 preferably has a sea-island structure.

  FIG. 2 shows an observation image obtained by observing the cured product with a transmission electron microscope (TEM). In the observation image arranged on the left of the upper stage, in the upper part of the observation image, there are a dark portion which is a matrix portion (hereinafter also referred to as “sea phase”) and a domain portion (hereinafter also referred to as “island phase”). You can see a light colored part. Even in the observation image arranged on the right in the upper stage, a dark portion that is a matrix portion and a light portion that is a domain portion can be confirmed above the observation image. A circular object is a filler.

As shown in FIG. 2, the cured product has a sea-island structure including a matrix portion and a domain portion. The matrix part is softer than the domain part. The cured product includes a filler dispersed in the matrix portion.
In addition, hardened | cured material is obtained by heating the thermosetting composition 11 at 150 degreeC for 1 hour, for example.

  The softness of the matrix portion and the domain portion can be known by, for example, an atomic force microscope (AFM).

  In FIG. 3, a lightly colored portion (a portion that is not black) is a portion with a small phase delay. The portion where the phase delay is small has low adsorptivity and is hard. On the other hand, the dark portion is a portion having a large phase delay. The portion where the phase delay is large has high adsorptivity and is soft.

  By being able to form a sea-island structure including a domain part and a matrix part softer than the domain part, the flow can be controlled, and the amount of the thermosetting composition 11 entering the space between the substrate and the electronic device can be reduced. Can be reduced.

  The matrix portion includes an acrylic polymer as a main component. The domain part contains a thermosetting resin as a main component.

  By comparing the observation result of the AFM and the observation result of the transmission electron microscope (TEM) with respect to the cured product, it can be clarified that the matrix portion contains the acrylic polymer as a main component. It can be clearly seen that the domain part contains a thermosetting resin as a main component.

  For reference, FIG. 4 shows a TEM observation image of the cured product used in FIG. The dark portion is a low luminance region and is a portion containing an acrylic polymer as a main component.

  The thermosetting composition 11 capable of forming a sea-island structure including a domain part and a matrix part softer than the domain part can be obtained by adjusting the type of functional group of the acrylic polymer, the content of the acrylic polymer, and the like.

  By increasing the content of the acrylic polymer, a matrix part softer than the domain part can be easily formed.

  The maximum particle size of the domain part is preferably 0.01 μm or more, more preferably 0.03 μm or more, and further preferably 0.05 μm or more. The flow of the thermosetting composition 11 can be regulated as it is 0.01 μm or more. On the other hand, the maximum particle size of the domain part is preferably 5 μm or less, more preferably 4 μm or less, further preferably 3 μm or less, more preferably 1 μm or less, further preferably 0.8 μm or less, and further preferably 0.5 μm or less. . When it is 5 μm or less, it is possible to impart a thixotropic effect, and the flow of the thermosetting composition 11 can be regulated.

  The maximum particle size of the domain part can be controlled by the amount of the functional group of the acrylic polymer. For example, the maximum particle size of the domain part can be reduced by blending an acrylic polymer having a large amount of functional groups. The compatibility between the thermosetting resin and the acrylic polymer also affects the maximum particle size of the domain part. However, the amount of the functional group of the acrylic polymer has a greater influence.

  The maximum particle size of the domain part is the maximum distance among the distances between two points on the outline of the domain part in an observation image observed with a transmission electron microscope (TEM). The maximum particle size of the domain part can be calculated by averaging measured values obtained by observing 100 domain parts. In the case where a plurality of domain parts are present in an aggregated or aggregated state, a domain whose contour is continuous is handled as one domain part.

  The method for producing the sealing sheet 1 is not particularly limited. For example, a resin for forming the thermosetting composition 11 is dissolved and dispersed in an appropriate solvent to adjust the varnish, and this varnish is applied to the separator 12. After the coating film is applied to a predetermined thickness to form a coating film, the coating film is dried under a predetermined condition, whereby the sealing sheet 1 can be obtained. The application method is not particularly limited, and examples thereof include roll coating, screen coating, and gravure coating. As drying conditions, for example, the drying temperature is 70 to 160 ° C. and the drying time is 1 to 30 minutes. Further, a varnish is applied on a separator different from the separator 12 to form a coating film, and the coating film is dried to form a thermosetting composition 11, and then the thermosetting composition 11 is pasted on the separator 12. A matching method is also suitable. Examples of the solvent include methyl ethyl ketone, ethyl acetate, toluene and the like.

  It is also preferable to manufacture the thermosetting composition 11 by kneading extrusion. Thereby, the thermosetting composition 11 which can be easily formed into a sheet, has few voids, and has a uniform thickness is obtained. As a method for producing by kneading extrusion, for example, a method in which a kneaded product obtained by kneading the respective components (for example, inorganic filler, acrylic polymer, etc.) is plastically processed into a sheet shape is preferable. By producing by kneading extrusion, the inorganic filler can be highly filled.

Specifically, a kneaded product is prepared by melting and kneading a thermosetting resin, a curing accelerator, an acrylic polymer, an inorganic filler, and the like with a known kneader such as a mixing roll, a pressure kneader, and an extruder. The obtained kneaded material is plastically processed into a sheet shape. As kneading conditions, the upper limit of the temperature is preferably 140 ° C. or less, and more preferably 130 ° C. or less. The lower limit of the temperature is preferably equal to or higher than the softening point of each component described above, for example, 30 ° C or higher, and preferably 50 ° C or higher. The kneading time is preferably 1 to 30 minutes. The kneading is preferably performed under reduced pressure conditions (under reduced pressure atmosphere), and the pressure under reduced pressure conditions is, for example, 1 × 10 ^{−4 to} 0.1 kg / cm ² .

  The kneaded material after melt-kneading is preferably subjected to plastic working in a high temperature state without cooling. The plastic working method is not particularly limited, and examples thereof include a flat plate pressing method, a T die extrusion method, a screw die extrusion method, a roll rolling method, a roll kneading method, an inflation extrusion method, a coextrusion method, and a calendering method. The plastic processing temperature is preferably higher than 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.

  Although the thickness of the thermosetting composition 11 is not specifically limited, Preferably it is 100 micrometers or more, More preferably, it is 150 micrometers or more. The thickness of the thermosetting composition 11 is preferably 2000 μm or less, more preferably 1000 μm or less.

  The sealing sheet 1 is used for manufacturing a package. The package includes an electronic device. Examples of the electronic devices include sensors, MEMS (Micro Electro Mechanical Systems), SAW (Surface Acoustic Wave) chips, semiconductor elements, capacitors, resistors, and the like. Examples of the sensor include a pressure sensor and a vibration sensor. Examples of the semiconductor element include a semiconductor chip, an IC (integrated circuit), and a transistor.

  The package includes, for example, a substrate, an electronic device mounted on the substrate, and a protection unit that covers the electronic device. Examples of the substrate include a printed wiring board, a LTCC (Low Temperature Co-fired Ceramics) substrate (low temperature co-fired ceramic substrate), a ceramic substrate, a silicon substrate, and a metal substrate. The protection part is formed by curing the thermosetting composition 11.

  A hollow package can be illustrated as a package. In the hollow package, a space is provided between the electronic device and the substrate. Examples of the hollow package include a sensor package, a MEMS package, and a SAW filter.

  As a method of manufacturing a package using the sealing sheet 1, for example, there is a method of embedding an electronic device in the thermosetting composition 11.

(Package manufacturing method)
As shown in FIG. 5, the package manufacturing method includes a step of pressurizing the stacked body 331. The laminated body 331 includes the device mounting body 302 and the thermosetting composition 11 disposed on the device mounting body 302. The laminated body 331 further includes a separator 12 disposed on the thermosetting composition 11. The device mounting body 302 includes a substrate 322 and an electronic device 323 mounted on the substrate 322. The step of pressurizing the stacked body 331 includes the step of pressing the stacked body 331 with the lower heating plate 341 and the upper heating plate 342.

  As shown in FIG. 6, the sealing body 332 is obtained by the process which pressurizes the laminated body 331. As shown in FIG. The sealing body 332 includes the substrate 322, the electronic device 323 mounted on the substrate 322, and the thermosetting composition 11 that covers the electronic device 323. The package manufacturing method further includes a step of heating the sealing body 332. A structure body 333 is obtained by a process of heating the sealing body 332.

  As illustrated in FIG. 7, the structure 333 includes a substrate 322, an electronic device 323 mounted on the substrate 322, and a protection unit 326 that covers the electronic device 323. The method for manufacturing the package further includes a step of dividing the structure 333 for each electronic device 323. A package 334 is obtained by dividing the structure 333 for each electronic device 323.

  As illustrated in FIG. 8, the package 334 includes a substrate 322, an electronic device 323 mounted on the substrate 322, and a protection unit 326 that covers the electronic device 323.

  In the following, the SAW filter manufacturing method will be described as a representative of the package manufacturing methods.

(Method for producing SAW filter)
As shown in FIG. 9, the laminate 31 is disposed between the lower heating plate 41 and the upper heating plate 42. The laminated body 31 includes a device mounting body 2, a thermosetting composition 11 disposed on the device mounting body 2, and a separator 12 disposed on the thermosetting composition 11.

  The device mounting body 2 includes a substrate 22 and a SAW chip 23 mounted on the substrate 22. The SAW chip 23 can be obtained by dicing the piezoelectric crystal on which the predetermined comb-shaped electrode is formed into pieces by a known method. The SAW chip 23 can be fixed to the substrate 22 using a known device such as a flip chip bonder or a die bonder. The SAW chip 23 and the substrate 22 are electrically connected via protruding electrodes 24 such as bumps. Further, a hollow portion 25 is disposed between the SAW chip 23 and the substrate 22 so as not to inhibit the propagation of the surface acoustic wave on the surface of the SAW filter. The distance between the SAW chip 23 and the substrate 22 (hereinafter also referred to as the width of the hollow portion 25) can be set as appropriate, and is generally about 10 μm to 100 μm. That is, the device mounting body 2 includes the substrate 22, the protruding electrode 24 disposed on the substrate 22, and the SAW chip 23 disposed on the protruding electrode 24.

  As shown in FIG. 10, the laminated body 31 is hot-pressed by a parallel plate method using the lower heating plate 41 and the upper heating plate 42 to form the sealing body 32.

  The temperature of the hot press is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, and further preferably 60 ° C. or higher. It can seal tightly that it is 40 degreeC or more. The temperature of the hot press is preferably 150 ° C. or lower, more preferably 90 ° C. or lower, and further preferably 80 ° C. or lower. When the temperature is 150 ° C. or lower, the curing reaction does not proceed excessively before molding by hot pressing, and therefore, it can be tightly sealed.

  The pressure at which the laminate 31 is hot-pressed is preferably 0.1 MPa or more, more preferably 0.5 MPa or more, and further preferably 1 MPa or more. Moreover, the pressure which heat-presses the laminated body 1 becomes like this. Preferably it is 10 MPa or less, More preferably, it is 8 MPa or less. When the pressure is 10 MPa or less, the SAW chip 23 is not seriously damaged.

  The time for hot pressing is preferably 0.3 minutes or more, more preferably 0.5 minutes or more. The time for hot pressing is preferably 10 minutes or less, more preferably 5 minutes or less.

  The hot pressing is preferably performed in a reduced pressure atmosphere. By hot pressing in a reduced-pressure atmosphere, voids can be reduced and irregularities can be filled well. As pressure reduction conditions, a pressure is 0.01 kPa-5 kPa, for example, Preferably, it is 0.1 Pa-100 Pa.

  The sealing body 32 obtained by hot pressing the laminated body 31 includes the substrate 22, the SAW chip 23 mounted on the substrate 22, and the thermosetting composition 11 that covers the SAW chip 23. A separator 12 is disposed on the sealing body 32.

  As shown in FIG. 11, the separator 12 is peeled off.

  The thermosetting composition 11 is cured by heating the sealing body 32 to form the structure 33.

  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. It is preferable to heat the sealing body 32 in a pressurized atmosphere, and the pressure is preferably 0.1 MPa or more, more preferably 0.5 MPa or more. On the other hand, the upper limit is preferably 10 MPa or less, more preferably 5 MPa or less. It is also preferable to heat the sealing body 32 under atmospheric pressure.

  As shown in FIG. 12, the structure 33 includes a substrate 22, a SAW chip 23 mounted on the substrate 22, and a protection unit 26 that covers the SAW chip 23.

  As shown in FIG. 13, the structure 33 is divided into pieces (dicing) to obtain the SAW filter 34. The SAW filter 34 includes a substrate 22, a SAW chip 23 mounted on the substrate 22, and a protection unit 26 that covers the SAW chip 23. A space is provided between the SAW chip 23 and the substrate 22.

  Bumps may be formed on the SAW filter 34 and mounted on a separate substrate (not shown). For mounting the SAW filter 34 on a substrate, a known device such as a flip chip bonder or a die bonder can be used.

(Modification 1)
As shown in FIG. 14, the sealing sheet 1 of Modification 1 includes a separator 12, a thermosetting composition 11 disposed on the separator 12, and a separator 13 disposed on the thermosetting composition 11. . Examples of the separator 13 include a polyethylene terephthalate (PET) film. The separator 13 is preferably subjected to a mold release treatment.

(Modification 2)
In the modified example 2, the thermosetting composition 11 has a multilayer structure including a plurality of layers.

(Modification 3)
In the first embodiment, the stacked body 331 is pressed by a parallel plate method, but in the modified example 3, the stacked body 331 is pressed using a laminator.

  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.

[Production of thermosetting sheet]
The components used for producing the thermosetting sheet will be described.
Epoxy resin: YSLV-80XY manufactured by Nippon Steel Chemical Co., Ltd. (bisphenol F type epoxy resin, Epokin equivalent: 200 g / eq., Softening point: 80 ° C.)
Phenol resin: LVR-8210DL (Novolak-type phenol resin, hydroxyl equivalent: 104 g / eq., Softening point: 60 ° C.) manufactured by Gunei Chemical Co., Ltd.
Acrylic polymer: HME-2006M manufactured by Negami Kogyo Co., Ltd. (carboxyl group-containing acrylate copolymer, weight average molecular weight: about 600,000, Tg: -35 ° C., acid value: 32 mgKOH / g)
Inorganic filler 1: FB-5SDC (spherical silica, average particle size 5 μm) manufactured by Denki Kagaku Kogyo Co., Ltd.
Inorganic filler 2: SC220G-SMJ (manufactured by Admatechs) (silica having an average particle size of 0.5 μm surface-treated with 3-methacryloxypropyltrimethoxysilane)
Carbon black: # 20 manufactured by Mitsubishi Chemical
Curing accelerator: 2PHZ-PW (2-phenyl-4,5-dihydroxymethylimidazole) manufactured by Shikoku Kasei Kogyo Co., Ltd.

  According to the blending ratio shown in Table 1, each component was dissolved and dispersed in methyl ethyl ketone as a solvent to obtain a varnish having a concentration of 90% by weight. The varnish was applied on a release-treated polyethylene terephthalate film having a thickness of 38 μm after the release treatment with silicone, and then dried at 110 ° C. for 5 minutes. As a result, a sheet having a thickness of 42 μm was obtained. By laminating five sheets, a thermosetting sheet having a thickness of 210 μm was obtained.

[Production of cured product]
A cured product was obtained by heating and curing the thermosetting sheet at 150 ° C. for 1 hour using a heating oven.

[Preparation of observation sample]
An observation sheet was prepared in the same manner as the thermosetting sheet except that inorganic filler 1, inorganic filler 2 and carbon black were not blended. An observation sample was obtained by heating and curing the observation sheet at 150 ° C. for 1 hour using a heating oven.
The reason for preparing the observation sample is to observe the sea-island structure. The sea-island structure can be confirmed by observing the cured product, but the sea-island structure can be easily confirmed by observing the observation sample.

[Evaluation]
The following evaluation was performed on the thermosetting sheet, the cured product, and the observation sample. The results are shown in Table 1.

(TEM observation)
The presence or absence of phase separation was confirmed by observing the cut surface of the thermosetting sheet with TEM.

(Tensile storage modulus of cured product at 25 ° C)
A strip-shaped test piece having a length of 40 mm, a width of 10 mm, and a thickness of 200 μm was cut out from the cured product with a cutter knife. About the test piece, the storage elastic modulus in -50 degreeC-300 degreeC was measured using the solid viscoelasticity measuring apparatus (RSAIII, Rheometric Scientific Co., Ltd. product). The measurement conditions were a frequency of 1 Hz and a heating rate of 10 ° C./min.

(Tg of cured product)
A strip-shaped test piece having a length of 40 mm, a width of 10 mm, and a thickness of 200 μm was cut out from the cured product with a cutter knife. About the test piece, the storage elastic modulus in -50 degreeC-300 degreeC was measured using the solid viscoelasticity measuring apparatus (RSAIII, Rheometric Scientific Co., Ltd. product). The measurement conditions were a frequency of 1 Hz and a heating rate of 10 ° C./min. Furthermore, Tg was obtained by calculating the value of tan δ (G ″ (loss elastic modulus) / G ′ (storage elastic modulus)).

(CTE1)
A measurement sample having a length of 15 mm, a width of 5 mm, and a thickness of 200 μm was cut out from the cured product. After setting the measurement sample on a film tensile measurement jig of a thermomechanical analyzer (TMA8310 manufactured by Rigaku Corporation), conditions of a tensile load of 2 g and a heating rate of 5 ° C./min in a temperature range of −50 ° C. to 300 ° C. CTE1 was computed from the expansion coefficient in 50 to 70 degreeC.

(Phase separation of observation sample)
The presence or absence of phase separation was confirmed by observing the cut surface of the observation sample with a TEM.

(AFM observation of observation sample)
By observing the cut surface of the observation sample with AFM, it was confirmed which of the thermosetting resin and the acrylic polymer was the main component for the sea phase. Regarding the island phase, it was confirmed which of the thermosetting resin and the acrylic polymer is the main component.

[Evaluation]
The following evaluation was performed using a thermosetting sheet. The results are shown in Table 1.

(Warpage amount)
As shown in FIG. 15, an alumina substrate 122 (alumina substrate manufactured by Kyocera Corporation, length 102 mm × width 102 mm × thickness 0.2 mm) and a thermosetting sheet 111 (length 102 mm × width 102 mm ×) disposed on the alumina substrate 122. A test laminate 91 having a thickness of 0.21 mm) was hot-pressed under the conditions of 90 ° C. and 0.2 Pa using an instantaneous vacuum lamination apparatus (manufactured by Mikado Technos, VS008-1515). After the heat press, the test laminate 91 was heated at 150 ° C. for 1 hour using a dryer (STH-120 manufactured by ESPEC) to cure the thermosetting sheet 111. After such heating, the test laminate 91 was left at room temperature (25 ° C.) for 1 hour. As shown in FIG. 16, the test laminate 91 was placed on the desk 201, and the distance 301 between the corner of the test laminate 91 and the desk 201 was measured with a ruler.

(Resin intrusion into hollow part)
A SAW chip having the following specifications having an aluminum comb electrode was mounted on a ceramic substrate under the following bonding conditions to produce a SAW chip mounting substrate having a ceramic substrate and a SAW chip mounted on the ceramic substrate. The gap width between the SAW chip and the ceramic substrate was 20 μm.

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

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

  A laminate was obtained by disposing a thermosetting sheet on the SAW chip mounting substrate. The laminated body was vacuum-pressed by the parallel plate method under the heating and pressing conditions shown below to obtain a sealed body.

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

  After opening to atmospheric pressure, the sealing body was heated in a hot air dryer at 150 ° C. for 1 hour to obtain a structure. The interface between the ceramic substrate and the protective part was cleaved, and the amount of resin intrusion into the hollow part between the SAW chip and the ceramic substrate was measured with a product name “Digital Microscope” (200 times) manufactured by KEYENCE. The resin penetration amount was determined by measuring the maximum reach distance of the resin that entered the hollow portion from the end of the SAW chip, and setting this as the resin penetration amount. The case where the resin intrusion amount was 150 μm or less was determined as “◯”. The case where it exceeded 150 μm was determined as “x”.

1 Sealing sheet
DESCRIPTION OF SYMBOLS 2 Device mounting body 11 Thermosetting composition 12 Separator 13 Separator 22 Substrate 23 SAW chip 24 Projection electrode 25 Hollow part 26 Protection part 31 Laminated body 32 Sealing body 33 Structure 34 Hollow package 41 Lower heating plate 42 Upper heating plate

302 Device Mounted Body 322 Substrate 323 Electronic Device 326 Protection Unit 331 Laminated Body 332 Sealed Body 333 Structure 334 Package

Claims (2)

A thermosetting composition in the form of a sheet,
The thermosetting composition comprises an inorganic filler and a residual component;
The residual component comprises an acrylic polymer;
The content of the acrylic polymer in the residual component is 65% by weight or more,
The content of the inorganic filler in the thermosetting composition is 55% by volume or more,
The sheet | seat for sealing whose storage elastic modulus in 25 degreeC of the hardened | cured material obtained by hardening the said thermosetting composition is 5 * 10 < ⁷ > Pa-5 * 10 < ⁹ > Pa. Pressurizing a substrate and a device mounting body including an electronic device mounted on the substrate, and a laminate including a sheet-like thermosetting composition disposed on the device mounting body,
The thermosetting composition comprises an inorganic filler and a residual component;
The residual component comprises an acrylic polymer;
The content of the acrylic polymer in the residual component is 65% by weight or more,
The content of the inorganic filler in the thermosetting composition is 55% by volume or more,
The manufacturing method of the package whose storage elastic modulus in 25 degreeC of the hardened | cured material obtained by hardening the said thermosetting composition is 5 * 10 < ⁷ > Pa-5 * 10 < ⁹ > Pa.