Sealing sheet and element device

Abstract

To provide a sealing sheet which has the excellent embedding property to an element and also has the excellent flexibility and an element device.SOLUTION: A sealing sheet is a thermosetting sealing sheet which includes a thermosetting component, a thermoplastic component and an inorganic filler. The content ratio of the inorganic filler in the sealing sheet is equal to or less than 60 mass%. The viscosity at 90°C is equal to or less than 100kPa s. The tensile storage elastic modulus E' at 25°C of a cured body after thermal curing of the sealing sheet is equal to or less than 300 MPa. An element device 10 includes a substrate 2, an element 3 and a cured body 4. The cured body 4 is arranged on one side in the thickness direction of the substrate 2. The cured body 4 seals the element 3. The cured body 4 is the cured body after thermal curing of the sealing sheet 41. The cured body 4 is brought into contact with one surface, the other surface and the periphery side surface in the thickness direction of the element 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an encapsulating sheet and an element device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a thermosetting sealing sheet containing a thermosetting component, a thermoplastic component, and an inorganic filler has been known (for example, see Patent Document 1 below).

[0003] The encapsulating sheet can encapsulate the element mounted on the upper side of the substrate. The encapsulating sheet encapsulates the element and is thermally cured to form a cured body. The cured body contacts the upper surface and peripheral side surface of the element.

[0004] In each of Examples 1 to 6 of Patent Document 1, the content of the inorganic filler in the sealing sheet is 90 mass %. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-104648 A Summary of the Invention [Problem to be solved by the invention]

[0006] Depending on the application and purpose of the encapsulating sheet, excellent embeddability in an element is required. Embeddability is a property that allows a cured body to come into contact with the lower surface of an element. The encapsulating sheet described in Patent Document 1 has a problem of low embeddability.

[0007] In addition, depending on the application and purpose of the sealing sheet, the cured body is required to be flexible. If the cured body is not flexible, the cured body will be damaged when bent, and the sealing property of the cured body will be impaired. The cured body described in Patent Document 1 has low flexibility and therefore has insufficient sealing property.

[0008] The present invention provides an encapsulating sheet and an element device which have excellent embeddability for an element and excellent flexibility. [Means for solving the problem]

[0009] The present invention [1] is a thermosetting encapsulating sheet including a thermosetting component, a thermoplastic component, and an inorganic filler, wherein a content ratio of the inorganic filler in the encapsulating sheet is 60 mass% or less, a viscosity at 90°C is 100 kPa s or less, and a tensile storage modulus E' at 25°C of a cured body after thermal curing of the encapsulating sheet, which is obtained by measuring the cured body at a frequency of 1 Hz and a heating rate of 10°C / min, is 300 MPa or less.

[0010] Since the viscosity of the encapsulating sheet at 90°C is 100 kPa·s or less, when the encapsulating sheet encapsulates an element in an encapsulating step, the encapsulating sheet can efficiently enter between the other surface of the element in the thickness direction and one surface of the substrate in the thickness direction. Therefore, the encapsulating sheet has excellent embedding ability for an element.

[0011] Since the tensile storage modulus E' of the cured body after thermal curing of the encapsulating sheet at 25°C is 300 MPa or less, the cured body can be prevented from being damaged even when bent, and therefore the sealing property of the cured body for the element can be improved.

[0012] The present invention [2] includes the encapsulating sheet according to [1], wherein the cured product has a glass transition temperature of 50° C. or lower.

[0013] Since the cured product of this encapsulating sheet has a glass transition temperature of 50° C. or higher, it has excellent embeddability for elements.

[0014] The present invention [3] includes the encapsulating sheet according to [1] or [2], in which the glass transition temperature of the thermoplastic component is 20° C. or lower.

[0015] The present invention [4] includes the sheet for sealing according to any one of [1] to [3], wherein the thermoplastic component is an acrylic resin.

[0016] The present invention [5] includes the encapsulating sheet according to any one of [1] to [4], wherein the thermosetting component includes an epoxy resin, an epoxy resin curing agent, and an epoxy resin curing accelerator.

[0017] The present invention [6] includes the sealing sheet according to any one of [1] to [5], wherein a content ratio of the inorganic filler relative to 100 parts by mass of the thermoplastic component is 50 parts by mass or more and 300 parts by mass or less.

[0018] The present invention [7] includes an element device comprising a substrate, an element mounted on one side of the substrate in a thickness direction, and a cured body disposed on one side of the substrate in a thickness direction and sealing the element, the cured body being a cured body obtained after thermal curing of the sealing sheet described in any one of [1] to [6], wherein the cured body contacts one side, the other side, and a peripheral side surface of the element in the thickness direction. Effect of the Invention

[0019] The encapsulating sheet and element device of the present invention have excellent embeddability for elements and excellent flexibility. [Brief description of the drawings]

[0020] [Figure 1] 1A is a manufacturing process diagram and a usage diagram of an embodiment of the encapsulating sheet of the present invention, Fig. 1A is a process of preparing an encapsulating sheet, Fig. 1B is a process of manufacturing an element device, and Fig. 1C is a state in which the element device is bent. [Diagram 2] 2A and 2B are diagrams illustrating bending evaluation of an example, in which Fig. 2A shows the state where an end of the cured sheet is fixed to a pipe, and Fig. 2B shows the state where the cured sheet is wrapped around a pipe. [Diagram 3] FIG. 2 is an image-processed view showing an enlarged portion of the bottom photograph of the embedding test of Example 1. [Figure 4]FIG. 13 is an image-processed enlarged view of a portion of the bottom photograph of the embedding test of Example 2. [Diagram 5] FIG. 13 is an image-processed enlarged view of a portion of the bottom photograph of the embedding test of Example 3. [Figure 6] FIG. 13 is an image-processed view showing an enlarged portion of a bottom photograph of the embedding test of Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] 1. Composition of encapsulating sheet The encapsulating sheet of the present invention contains a thermosetting component, a thermoplastic component, and an inorganic filler, and therefore the encapsulating sheet is thermosetting.

[0022] 1.1 Thermosetting components The thermosetting component includes, for example, a thermosetting resin. Examples of the thermosetting resin include epoxy resin, silicone resin, urethane resin, polyimide resin, urea resin, melamine resin, and unsaturated polyester resin. These can be used alone or in combination of two or more. Examples of the thermosetting resin include epoxy resin. The thermosetting resin is preferably prepared as a composition. Specifically, the thermosetting resin is preferably prepared as a thermosetting resin composition including an epoxy resin, an epoxy resin curing agent, and an epoxy resin curing agent accelerator. In other words, the thermosetting component preferably includes an epoxy resin, an epoxy resin curing agent, and an epoxy resin curing agent accelerator.

[0023] 1.1.1 Epoxy resin Examples of the epoxy resin include bifunctional epoxy resins and trifunctional or higher polyfunctional epoxy resins. Examples of the bifunctional epoxy resin include bisphenol A type epoxy resins, bisphenol F type epoxy resins, modified bisphenol A type epoxy resins, modified bisphenol F type epoxy resins, and biphenyl type epoxy resins. Examples of the polyfunctional epoxy resin include phenol novolac type epoxy resins, cresol novolac type epoxy resins, trishydroxyphenylmethane type epoxy resins, tetraphenylolethane type epoxy resins, and dicyclopentadiene type epoxy resins. The epoxy resins can be used alone or in combination of two or more kinds. Examples of the epoxy resin include preferably bifunctional epoxy resins, more preferably bisphenol F type epoxy resins.

[0024] The content ratio of the epoxy resin in the thermosetting component is, for example, 40 mass % or more, preferably 50 mass % or more, and for example, 90 mass % or less, preferably 75 mass % or less.

[0025] 1.1.2 Epoxy resin hardener The epoxy resin curing agent is a component (latent curing agent) that can cure the above-mentioned epoxy resin by heating. Examples of the epoxy resin curing agent include phenolic resins. Examples of the phenolic resin include novolac-type phenolic resins and phenol-aralkyl resins. The phenolic resins can be used alone or in combination of two or more kinds. The phenolic resin is preferably a novolac-type phenolic resin.

[0026] The content ratio of the epoxy resin curing agent relative to 100 parts by mass of the epoxy resin is, for example, 10 parts by mass or more, preferably 50 parts by mass or more, and for example, 150 parts by mass or less, preferably 100 parts by mass or less. The content ratio of the epoxy resin curing agent in the thermosetting component is, for example, 10% by mass or more, preferably 25% by mass or more, and for example, 50% by mass or less, preferably 40% by mass or less.

[0027] 1.1.3 Epoxy resin curing accelerator The epoxy resin curing accelerator is a catalyst (thermosetting catalyst) that accelerates the curing of epoxy resin by heating. Examples of the epoxy resin curing accelerator include imidazole-based curing accelerators, phosphorus-based curing accelerators, and urea-based curing accelerators. These can be used alone or in combination of two or more kinds.

[0028] Examples of the imidazole-based curing accelerator include imidazole compounds, such as 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ).

[0029] The phosphorus-based curing accelerator may be an organic phosphorus compound, such as a triarylphosphine.

[0030] Examples of the urea-based curing accelerator include a urea compound containing a dialkylamino group. Examples of the dialkylamino group include dimethylamino. Examples of the urea-based curing accelerator include an aliphatic urea compound and an aromatic urea compound. Examples of the urea-based curing accelerator include an aliphatic urea compound.

[0031] The aliphatic urea compound contains, for example, the above-mentioned dialkylamino group and an aliphatic group. The aliphatic urea compound includes a dimethylamino group-containing aliphatic urea compound represented by the following formula (1).

[0032] [ka]

[0033] The content ratio of the epoxy resin curing accelerator relative to 100 parts by mass of the epoxy resin is, for example, 1 part by mass or more, preferably 2.5 parts by mass or more, and for example, 10 parts by mass or less, preferably 5 parts by mass or less. The content ratio of the epoxy resin curing accelerator in the thermosetting component is, for example, 0.5% by mass or more, preferably 1.5% by mass or more, and for example, 5% by mass or less, preferably 3% by mass or less.

[0034] The content ratio of the thermosetting component in the sealing sheet is, for example, 5 mass% or more, preferably 10 mass% or more, more preferably 15 mass% or more, even more preferably 20 mass% or more, particularly preferably 25 mass% or more, and for example, 35 mass% or less, preferably 30 mass% or less.

[0035] 1.2 Thermoplastic components Examples of the thermoplastic component include thermoplastic resins. Examples of the thermoplastic resins include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, polybutadiene resins, polycarbonate resins, thermoplastic polyimide resins, polyamide resins, phenoxy resins, acrylic resins, saturated polyester resins, polyamideimide resins, fluororesins, and styrene-isobutylene-styrene block copolymers. As the thermoplastic resin, preferably, acrylic resins are used from the viewpoint of improving embeddability and flexibility.

[0036] Examples of the acrylic resin include (meth)acrylic acid ester copolymers obtained by polymerizing monomer components including (meth)acrylic acid alkyl esters having linear or branched alkyl groups and other monomers. Examples of the (meth)acrylic acid ester copolymers include carboxyl group-containing acrylic acid ester copolymers and hydroxyl group-containing acrylic acid ester copolymers. Examples of the (meth)acrylic acid ester copolymers include carboxyl group-containing acrylic acid ester copolymers. Examples of the (meth)acrylic acid ester copolymers include carboxyl group-containing acrylic acid ester copolymers.

[0037] Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, isobutyl, pentyl, and hexyl. The number of carbon atoms in the alkyl group is, for example, 1 or more and 6 or less.

[0038] Examples of the other monomers include carboxyl group-containing monomers and hydroxyl group-containing monomers. Examples of the other monomers include carboxyl group-containing monomers. Examples of the carboxyl group-containing monomers include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the carboxyl group-containing monomers may include itaconic anhydride and maleic anhydride.

[0039] The weight average molecular weight of the thermoplastic component is, for example, 100,000 or more, preferably 500,000 or more, and for example, 1,000,000 or less, preferably 800,000 or less.

[0040] The glass transition temperature of the thermoplastic component is, for example, 20°C or lower, preferably 0°C or lower, more preferably -5°C or lower, and, for example, -70°C or higher, preferably -50°C or higher, more preferably -40°C or higher. If the glass transition temperature of the thermoplastic component is the above upper limit or lower, embeddability and flexibility can be improved. If the glass transition temperature of the thermoplastic component is the above lower limit or higher, the encapsulating sheet has excellent handleability.

[0041] If the thermoplastic component is a commercially available product, the glass transition temperature of the thermoplastic component may be the value listed in the catalog. Alternatively, the glass transition temperature of the thermoplastic component may be the theoretical value calculated by the Fox equation.

[0042] The content ratio of the thermoplastic component relative to 100 parts by mass of the thermosetting component is, for example, 50 parts by mass or more, preferably 100 parts by mass or more, more preferably 130 parts by mass or more, and, for example, 1,000 parts by mass or less, preferably, preferably, 500 parts by mass or less, more preferably, 300 parts by mass or less, even more preferably, 200 parts by mass or less, even more preferably, 160 parts by mass or less, and particularly preferably, 153 parts by mass or less. The content ratio (solid content ratio) of the thermoplastic component in the sealing sheet is, for example, 23% by mass or more, preferably 25% by mass or more, more preferably, 28% by mass or more, even more preferably, 30% by mass or more, especially preferably, 35% by mass or more, and most preferably, 40% by mass or more. Also, for example, 45% by mass or less, preferably 43% by mass or less, more preferably, 42% by mass or less.

[0043] 1.3 Inorganic fillers The inorganic filler is an inorganic component that improves the strength of the sealing sheet (and its cured product). Examples of the material of the inorganic filler include inorganic compounds. Examples of the inorganic compounds include quartz glass, talc, silica, alumina, aluminum nitride, silicon nitride, and boron nitride. These can be used alone or in combination of two or more. Preferably, silica is used.

[0044] The shape of the inorganic filler may be, for example, substantially spherical, substantially plate-like, substantially needle-like, or irregular. The shape of the inorganic filler is preferably substantially spherical.

[0045] The average value of the maximum length of the inorganic filler (average particle diameter if the filler is substantially spherical) is, for example, 0.1 μm or more, preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 5.0 μm or more, and is, for example, 50 μm or less, preferably 20 μm or less, and more preferably 10 μm or less. The average value of the maximum length of the inorganic filler is determined as the D50 value (cumulative 50% median diameter) based on the particle size distribution obtained by a particle size distribution measurement method in a laser scattering method.

[0046] The content of the inorganic filler in the sealing sheet is 60 mass % or less.

[0047] If the content ratio of the inorganic filler in the encapsulating sheet exceeds 60% by mass, the viscosity at 90° C. described below increases, and the embeddability in an element decreases.

[0048] The content of the inorganic filler in the sealing sheet is preferably 55 mass % or less, more preferably 53 mass % or less, further preferably 50 mass % or less, particularly preferably 40 mass % or less, and most preferably 35 mass % or less.

[0049] The content of the inorganic filler in the sealing sheet is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 25% by mass or more, and particularly preferably 30% by mass or more. If the content of the filler is equal to or more than the above-mentioned lower limit, the strength of the sealing sheet (and its cured body) can be improved.

[0050] The content ratio of the inorganic filler relative to 100 parts by mass of the thermosetting component is, for example, 50 parts by mass or more, preferably 80 parts by mass or more, more preferably 100 parts by mass or more, and even more preferably 150 parts by mass or more. The content ratio of the inorganic filler relative to 100 parts by mass of the thermosetting component is, for example, 1,000 parts by mass or less, preferably 500 parts by mass or less, more preferably 400 parts by mass or less, and even more preferably 300 parts by mass or less.

[0051] The content ratio of the inorganic filler relative to 100 parts by mass of the thermoplastic component is, for example, 25 parts by mass or more, preferably 50 parts by mass or more, and more preferably 70 parts by mass or more. When the content ratio of the inorganic filler relative to 100 parts by mass of the thermoplastic component is equal to or more than the above-mentioned lower limit, the flexibility of the cured body can be improved.

[0052] The content ratio of the inorganic filler relative to 100 parts by mass of the thermoplastic component is, for example, 500 parts by mass or less, preferably 300 parts by mass or less, more preferably 250 parts by mass or less, further preferably 200 parts by mass or less, and particularly preferably 175 parts by mass or less. When the content ratio of the inorganic filler relative to 100 parts by mass of the thermoplastic component is the above-mentioned upper limit or less, the embeddability of the sealing sheet in the element can be improved.

[0053] 1.4 Additives The encapsulating sheet may contain additives in addition to the thermosetting component, the thermoplastic component, and the inorganic filler. Examples of the additives include a silane coupling agent and a pigment.

[0054] The silane coupling agent may be, for example, a silane coupling agent containing an epoxy group. The silane coupling agent containing an epoxy group may be, for example, a glycidoxy alkyl dialkyl dialkoxy silane and a glycidoxy alkyl trialkoxy silane. The silane coupling agent containing an epoxy group may preferably be a glycidoxy alkyl trialkoxy silane. The glycidoxy alkyl trialkoxy silane may, for example, be 3-glycidoxy propyl trimethoxy silane and 3-glycidoxy propyl triethoxy silane. The glycidoxy alkyl trialkoxy silane may preferably be 3-glycidoxy propyl trimethoxy silane. The content of the silane coupling agent in the sealing sheet is, for example, 0.2 mass% or more, preferably 1 mass% or less.

[0055] An example of the pigment is carbon black. The average particle size of the pigment is, for example, 1 nm or more, preferably 10 nm or more, and, for example, 1,000 nm or less, preferably 100 nm or less. The content of the pigment in the sealing sheet is, for example, 0.1 mass% or more, preferably 0.5 mass% or more, and, for example, 2.5 mass% or less, preferably 1.5 mass% or less.

[0056] 1.5 Manufacturing of encapsulating sheets To produce a sealing sheet, the above-mentioned components are mixed in the above-mentioned ratio to prepare a thermosetting composition. Preferably, the above-mentioned components are thoroughly stirred. If necessary, a solvent (ketone compound) is further mixed to prepare a varnish. Thereafter, the composition (varnish) is applied to a release liner (not shown), and then dried by heating to produce a sealing sheet as a coating film. On the other hand, it is also possible to form a sealing sheet (coating film) from the composition by kneading extrusion without preparing a varnish. A thick sealing sheet can also be produced by stacking (pasting) multiple coating films.

[0057] The encapsulating sheet is in the B stage (semi-cured state), specifically, before the C stage. That is, the encapsulating sheet is before the complete curing. The encapsulating sheet is formed into a B stage sheet from the A stage composition by heating in the drying or heating in the extrusion kneading described above.

[0058] 1.6 Physical properties of encapsulating sheets The sheet for sealing has a thickness. The sheet for sealing extends, for example, in a plane direction. The plane direction is perpendicular to the thickness direction. Specifically, the sheet for sealing has one side and the other side opposed to each other in the thickness direction.

[0059] The encapsulating sheet has a thickness of, for example, 10 μm or more, or preferably 25 μm or more.The encapsulating sheet has a thickness of, for example, 1,000 μm or less, or preferably 500 μm or less.

[0060] The encapsulating sheet has a viscosity of 100 kPa·s or less at 90°C.

[0061] When the viscosity of the encapsulating sheet at 90° C. exceeds 100 kPa·s, the embeddability of the cured body in elements decreases.

[0062] The viscosity of the encapsulating sheet at 90°C is preferably 80 kPa·s or less, more preferably 60 kPa·s or less, even more preferably 40 kPa·s or less, particularly preferably 20 kPa·s or less, most preferably 15 kPa·s or less, further preferably 10 or less, further preferably 8 kPa·s or less, and further preferably 6 kPa·s or less.

[0063] The viscosity of the encapsulating sheet at 90° C. is, for example, 1 kPa·s or more, preferably 3 kPa·s or more, more preferably 5 kPa·s or more. When the viscosity of the encapsulating sheet at 90° C. is equal to or more than the above-mentioned lower limit, it is possible to prevent components of the encapsulating sheet from adhering to the surroundings and contaminating the surroundings when an element is encapsulated using the encapsulating sheet.

[0064] A method for measuring the viscosity of the encapsulating sheet will be described later in Examples.

[0065] 1.7 Physical properties of hardened material The tensile storage modulus E' at 25°C of the cured body (cured sheet) after the encapsulating sheet is thermally cured is 300 MPa or less.

[0066] If the tensile storage modulus E' of the cured body at 25°C exceeds 300 MPa, the flexibility of the cured body decreases, and the cured body is damaged when bent, and the sealing ability of the cured body to elements is impaired.

[0067] The tensile storage modulus E' of the cured body at 25°C is, for example, 250 MPa or less, preferably 200 MPa or less, more preferably 150 MPa or less, even more preferably 100 MPa or less, particularly preferably 80 MPa or less, and even more preferably 70 MPa or less, and even more preferably 60 MPa or less.

[0068] The tensile storage modulus E' of the cured product at 25°C is, for example, 1 MPa or more, preferably 10 MPa or more, more preferably 25 MPa or more, even more preferably 40 MPa or more, and particularly preferably 45 MPa or more. When the tensile storage modulus E' of the cured product at 25°C is equal to or more than the above-mentioned lower limit, the cured product has excellent handleability.

[0069] The tensile storage modulus E' of the cured product at 25°C is obtained by subjecting the cured product to dynamic viscoelasticity measurement at a frequency of 1 Hz and a heating rate of 10°C / min. Details of the conditions for dynamic viscoelasticity measurement will be described later in the Examples.

[0070] The cured product is a C-stage product in which the thermosetting component is completely cured. The conditions for thermosetting are not limited.

[0071] The glass transition temperature of the cured product is, for example, 50° C. or less, preferably 45° C. or less, more preferably 40° C. or less, even more preferably 35° C. or less, particularly preferably 30° C. or less, most preferably 25° C. or less, further preferably 24° C. or less, and even more preferably 20° C. or less. When the glass transition temperature of the cured product is equal to or less than the above upper limit, the embeddability of the cured product in an element can be improved.

[0072] The glass transition temperature of the cured product is, for example, −20° C. or higher, preferably 0° C. or higher, more preferably 5° C. or higher, and particularly preferably 10° C. or higher. When the glass transition temperature of the cured product is equal to or higher than the above-mentioned lower limit, the handleability of the cured product can be improved.

[0073] The glass transition temperature of the cured product is the peak top temperature of the loss tangent (tan δ) obtained by dynamic viscoelasticity measurement. The conditions for dynamic viscoelasticity measurement will be described in the examples below.

[0074] 1.8 Device Next, one embodiment of an element device including the above-mentioned cured body will be described with reference to FIGS. 1A and 1B.

[0075] As shown in FIG. 1B, the element device 10 has a thickness. The element device 10 extends in a planar direction. The element device 10 has a plate shape. The element device 10 is preferably flexible. If the element device 10 has flexibility, it is suitable for use in applications requiring flexibility. Examples of applications include wearable applications. The element device 10 includes a substrate 2, an element 3, and a cured body 4.

[0076] The substrate 2 is disposed at the other end of the element device 10 in the thickness direction. The substrate 2 has a thickness. The substrate 2 extends in the planar direction. The substrate 2 has a plate shape. The substrate 2 is preferably flexible. Examples of materials for the substrate 2 include resin, ceramic, and metal. Examples of materials for the substrate 2 include preferably resin, more preferably flexible resin, and even more preferably polyester resin. The thickness of the substrate 2 is, for example, 10 μm or more, and, for example, 1,000 μm or less.

[0077] The element 3 is mounted on one side in the thickness direction of the substrate 2. In this embodiment, the element 3 is preferably flip-chip mounted on one side in the thickness direction of the substrate 2. For example, a plurality of elements 3 are provided on the substrate 2. Each of the plurality of elements 3 is spaced apart from one another in the planar direction. Each of the plurality of elements 3 has a thickness. The elements 3 extend in the planar direction. The elements 3 have a plate shape.

[0078] The element 3 has an electrode (not shown). In this embodiment, the electrode is disposed on the other surface of the element 3 in the thickness direction. The electrode is electrically connected to one surface of the substrate 2 in the thickness direction via a bump 5. In this embodiment, the element 3 is preferably a hollow element. The element 3 includes, for example, a semiconductor. The thickness of the element 3 is, for example, 50 μm or more and, for example, 500 μm or less.

[0079] The bumps 5 are provided on the element device 10. A plurality of bumps 5 are provided for one element 3. Each of the plurality of bumps 5 extends in the thickness direction. The plurality of bumps 5 are spaced apart from one another in the planar direction. The plurality of bumps 5 are disposed between the substrate 2 and the element 3. Examples of materials for the bumps 5 include metal.

[0080] The cured body 4 is disposed at one end of the element device 10 in the thickness direction. The cured body 4 is a cured product obtained after the above-mentioned sealing sheet is thermally cured. The cured body 4 is disposed on one side of the substrate 2 in the thickness direction. The cured body 4 seals the multiple elements 3. The cured body 4 has a thickness. The cured body 4 extends in the surface direction. In this embodiment, the cured body 4 has a sheet shape. That is, in this embodiment, the cured body 4 is a cured body sheet. The cured body 4 is preferably flexible. The cured body 4 contacts one side of the substrate 2 in the thickness direction, one side of the element 3 in the thickness direction, the other side of the element 3 in the thickness direction, the peripheral side of the element 3, and the peripheral side of the bump 5. The peripheral side of the element 3 connects the one side and the other side of the element 3 in the thickness direction.

[0081] As a result, the cured body 4 is filled between one surface of the substrate 2 in the thickness direction and the other surface of the element 3 in the thickness direction. In this embodiment, the cured body 4 described above functions as an underfill for the element 3.

[0082] Furthermore, the element device 10 is permitted to include a gap 6 shown by a virtual line. When the element device 10 includes the gap 6, the gap 6 preferably exposes a central portion of the other side of the element 3 and a central portion of one side of the substrate 2 facing the element 3. The gap 6 is defined by the other side of the element 3, one side of the substrate 2, and the inner peripheral surface of the hardened body 4. In other words, the gap 6 is a region (unfilled portion) between the element 3 and the substrate 2 that is not filled with the hardened body 4. The inner peripheral surface of the hardened body 4 is disposed inside the peripheral edge of the other side of the element 3.

[0083] 1.9 Manufacturing method of element device The method for manufacturing the element device includes, for example, a preparation step and a sealing step.

[0084] 1.9.1 Preparation process 1A, in the preparation step, the above-described sealing sheet 41 and element-mounted substrate 21 are prepared. The element-mounted substrate 21 includes the above-described substrate 2 and the above-described element 3.

[0085] 1.9.2 Sealing process 1B, in the sealing step, the elements 3 in the element-mounted substrate 21 are sealed using a sealing sheet 41. The sealing step includes, for example, a pressing step and a heating step. The pressing step and the heating step are performed in this order.

[0086] 1.9.2.1 Pressing process In the pressing step, first, the sealing sheet 41 and the element-mounted substrate 21 are pressed together using a press (not shown). When pressing, the sealing sheet 41 is heated as necessary. At this time, the sealing sheet 41 is plastically deformed in accordance with the outer shape of the element 3. As a result, the sealing sheet 41 covers the element 3. In detail, the sealing sheet 41 enters between the other side of the element 3 and one side of the substrate 2 in the thickness direction from the peripheral edge of the other side of the element 3 in the thickness direction. As a result, the sealing sheet 41 contacts one side of the substrate 2 in the thickness direction, one side of the element 3 in the thickness direction, the other side of the element 3 in the thickness direction, the peripheral side of the element 3, and the peripheral side of the bump 5. Note that the sealing sheet 41 is still in the B stage.

[0087] 1.9.2.2 Heating process Thereafter, the element-mounted substrate 21 and the sealing sheet 41 are heated, whereby the sealing sheet 41 is thermally cured to form a cured body 4 in a C-stage.

[0088] In this way, the above-mentioned element device 10 is manufactured.

[0089] 1.10 Purpose There is no limitation on the application of the element device 10. Preferably, the element device 10 is used for wearable applications.

[0090] 2. Effects 1B , when the sealing sheet 41 seals the element 3 in the sealing step, the sealing sheet 41 can efficiently enter between the other surface of the element 3 in the thickness direction and one surface of the substrate 2 in the thickness direction. Therefore, the sealing sheet 41 has excellent embedding ability for the element 3.

[0091] Since the tensile storage modulus E' at 25°C of the cured body 4 after thermal curing of the sealing sheet 41 is 300 MPa or less, even if the cured body 4 is bent, damage to the cured body 4 can be suppressed as shown in Fig. 1C. Therefore, the sealing ability of the cured body to the element 3 can be improved.

[0092] If the cured body 42 of the sealing sheet 41 has a glass transition temperature of 50° C. or higher, the sheet has excellent embeddability for the element 3 .

[0093] 3. Variations In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, each modification can achieve the same effects as those in the above-described embodiment, unless otherwise specified. Furthermore, the embodiment and its modifications can be appropriately combined.

[0094] In the sealing step, the pressing step and the heating step may be carried out simultaneously.

[0095] Although not shown, the element 3 may be pillar-connected to the substrate 2.

[0096] Although not shown, the element 3 may be connected to the substrate 2 by wire bonding. In this case, the cured body 4 does not contact the other surface of the element 3 in the thickness direction.

[0097] The element 3 may be singular. EXAMPLES

[0098] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the examples and comparative examples. The specific numerical values ​​of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit (a numerical value defined as "not more than" or "less than") or lower limit (a numerical value defined as "not less than" or "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Form for carrying out the invention".

[0099] The components used in the examples and comparative examples are shown below.

[0100] Epoxy resin: YSLV-80XY, bisphenol F type epoxy resin manufactured by Nippon Steel Chemical Co., Ltd. Phenolic resin: Gun-ei Chemical's LVR-8210DL, novolac type phenolic resin Urea-based curing accelerator: U-CAT 3513N manufactured by San-Apro Co., Ltd., an aliphatic urea compound represented by the above formula (1) Acrylic resin: HME-2006M manufactured by Negami Chemical Industries, acrylic acid ester copolymer containing carboxyl group, methyl ethyl ketone solution with solid content concentration of 80% by mass, weight average molecular weight: about 600,000, glass transition temperature: -30℃ Inorganic filler: Denka 8SMFD, spherical silica powder, average particle size 7.0 μm Silane coupling agent: Shin-Etsu Chemical's KBM-403, 3-glycidoxypropyltrimethoxysilane Carbon black: Mitsubishi Chemical #20, pigment, particle size 50 nm

[0101] Example 1 A coating film was formed by applying varnish to the surface of a release liner made of a polyethylene terephthalate film (PET film). The surface of the release liner was subjected to a silicone release treatment. The varnish was prepared by blending and mixing the components according to the recipe shown in Table 1. The coating film was then heated and dried at 120°C for 2 minutes to produce a coating film with a thickness of 50 μm on the surface of the release liner. The coating film was in the B stage. Two coating films were then bonded together at 90°C to produce a sealing sheet 41 with a thickness of 100 μm. The sealing sheet 41 was also in the B stage.

[0102] [evaluation] [Viscosity of encapsulating sheet 41] A test sheet having a thickness of about 1 mm was prepared by laminating a plurality of sealing sheets 41. Then, the test sheet was processed into a circular shape having a diameter of 8 mm.

[0103] The viscosity of the test sheet at 90° C. was measured by a parallel plate method using a rheometer (MARS III, manufactured by HAAKE Co., Ltd.) In detail, the viscosity of the sealing sheet 41 at 90° C. was measured under the conditions of a gap of 0.8 mm, a parallel plate diameter of 8 mm, a frequency of 1 Hz, a strain of 0.005%, and an isothermal temperature of 90° C.

[0104] [Tensile storage modulus E' and glass transition temperature of cured sheet] First, the sealing sheet 41 was heated at 150° C. for 1 hour to produce a cured sheet 42. The cured sheet 42 was rectangular with a short side length of 5 mm and a long side length of 40 mm.

[0105] Next, the cured sheet 42 was subjected to dynamic viscoelasticity measurement under the conditions described below to determine the tensile storage modulus E' of the cured sheet 42 at 25°C.

[0106] Dynamic viscoelasticity measuring device: Product name "RSA-G2", manufactured by TA Instruments Chuck distance: 20mm Mode:Tension Temperature range: -10℃ to 260℃ Heating rate: 10℃ / min Frequency: 1Hz Distortion: 0.05%

[0107] In the above measurement, the tensile loss modulus E'' was also measured. The loss tangent (tan δ) was obtained from the tensile storage modulus E' and the tensile loss modulus E'', and the glass transition temperature of the cured sheet 42 was calculated from the peak top temperature of the loss tangent.

[0108] [Flexibility evaluation] The flexibility of the cured sheet 42 was evaluated by carrying out the following first to third steps.

[0109] 2A, first, a laminate having a plurality of encapsulating sheets 41 laminated thereon was heated at 150° C. for 1 hour to produce a thermally cured cured sheet 42. The cured sheet 42 was rectangular, with a short side length of 50 mm, a long side length of 70 mm, and a thickness of 400 μm.

[0110] Separately, a polyvinyl chloride pipe 7 having an outer diameter of 18 mm was prepared.

[0111] Second step: One end of the cured sheet 42 in the longitudinal direction was fixed to the peripheral surface of the pipe 7 using adhesive tape 8. Then, the cured sheet 42 was wrapped around the pipe 7, as shown in FIG. 2B.

[0112] Third step: The surface of the hardened sheet 42 wrapped around the pipe 7 was observed. If there were cracks on the surface of the hardened sheet 42, it was rated as "X". If there were no cracks on the surface of the hardened sheet 42, it was rated as "O".

[0113] [Embeddability evaluation] The following steps 1 to 4 were carried out in order.

[0114] First step: As shown in FIG. 1A, a plurality of sealing sheets 41 were laminated to prepare a sealing sheet 41 having a thickness of 200 μm. Separately, a glass substrate 2 and a dummy element 30 mounted on one side of the substrate 2 via a plurality of glass dummy bumps 50 were prepared. Nine dummy elements 30 were prepared. The size of each of the nine dummy elements 30 was 1 mm×1 mm×thickness 200 μm. The nine dummy elements 30 were arranged at intervals of 300 μm. The nine dummy elements 30 were aligned in three vertical rows and three horizontal rows. The length of the dummy bumps 50 in the thickness direction was 50 μm. The length between the other side of the dummy element 30 and one side of the substrate 2 was 50 μm.

[0115] Second step: As shown in FIG. 1B, the sealing sheet 41 was pressed against the substrate 2 by a vacuum plate press at a temperature of 65° C., a degree of vacuum of 1.6 kPa or less, and a pressing pressure of 0.2 MPa for 40 seconds.

[0116] Third step: The encapsulating sheet 41 was heated at 150° C. for 1 hour under atmospheric pressure to thermally cure the encapsulating sheet 41. As a result, a cured body 4 was formed.

[0117] Fourth step: The cured body 4 disposed between one surface of the substrate 2 and the other surface of the element 3 was observed from the other side of the substrate 2. The embeddability was evaluated according to the following criteria.

[0118] ◯: The ratio of the area of ​​the observed cured body 4 to the area of ​​the other surface of the element 3 was 0.9 or more. However, the area of ​​the other surface of the element 3 does not include the area of ​​the multiple dummy bumps 50. The same applies to the following criteria. Fig. 3 shows an image processing diagram of a partially enlarged bottom photograph of Example 1 as an example of the evaluation of ○. The dashed white line in Fig. 3 represents the outline of the element 3. Fig. 4 shows an image processing diagram of a partially enlarged bottom photograph of Example 2 as another example of the evaluation of ○. Fig. 5 shows an image processing diagram of a partially enlarged bottom photograph of Example 3 as another example of the evaluation of ○.

[0119] Δ: The ratio of the area of ​​the observed cured body 4 to the area of ​​the other surface of the element 3 was 0.7 or more and less than 0.9.

[0120] × The ratio of the area of ​​the observed cured body 4 to the area of ​​the other surface of the element 3 was less than 0.7. However, the area of ​​the other surface of the element 3 does not include the area of ​​the multiple dummy bumps 50. FIG. 6 shows an image-processed view of a partially enlarged bottom photograph of Comparative Example 2 as an example of an x ​​rating.

[0121] [Table 1] [Explanation of symbols]

[0122] 1. Sealing sheet 2. Board 3 Elements 4 Hardened body 10. Element device 41 Sealing sheet 42 Hardened Sheet E' Tensile storage modulus

Claims

1. A thermosetting sealing sheet including a thermosetting component, a thermoplastic component, and an inorganic filler, The content ratio of the inorganic filler in the sealing sheet is 60 mass% or less, The viscosity at 90°C is 100 kPa·s or less, The tensile storage modulus E' at 25°C of a cured body of the sealing sheet after thermal curing, which is obtained by measuring the cured body at a frequency of 1 Hz and a heating rate of 10°C / min, is 300 MPa or less.

2. The sealing sheet according to claim 1, wherein the cured product has a glass transition temperature of 50° C. or lower.

3. The sealing sheet according to claim 1 or 2, wherein the thermoplastic component has a glass transition temperature of 20° C. or lower.

4. The sealing sheet according to claim 1 or 2, wherein the thermoplastic component is an acrylic resin.

5. The sealing sheet according to claim 1 or 2, wherein the thermosetting component comprises an epoxy resin, an epoxy resin curing agent, and an epoxy resin curing accelerator.

6. The sealing sheet according to claim 1 or 2, wherein a content ratio of the inorganic filler relative to 100 parts by mass of the thermoplastic component is 50 parts by mass or more and 300 parts by mass or less.

7. A substrate; An element mounted on one side of the substrate in a thickness direction; a cured body disposed on one side of the substrate in a thickness direction and sealing the element, the cured body being obtained by thermal curing of the sealing sheet according to claim 1 or 2; The hardened body contacts one surface, the other surface and a peripheral side surface of the element in a thickness direction.

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