Sealing sheet and electronic device

Abstract

To provide a sealing sheet capable of preventing a sealed electronic component from being seen through while enabling an electronic device to be made thinner and an electronic device in which an electronic component is sealed using the sealing sheet.SOLUTION: A sealing sheet 1 is used for sealing a flip-chip mounted electronic component 12. The sealing sheet 1 includes a sealing resin layer 2 containing an epoxy resin, a phenol resin, an inorganic filler, and a dye. A blending ratio of the dye in the sealing resin layer 2 excluding the inorganic filler is 4 mass% or more and 15 mass% or less. A thickness ratio measured by a sealing test is 30% or less.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, encapsulating sheets (thermosetting adhesive sheets) used for encapsulating flip-chip mounted electronic components have been known (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-311348 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for further thinning of electronic devices using an encapsulating sheet as described in Patent Document 1. However, when the encapsulating sheet is made thinner, there is a problem that electronic components can be seen through.

[0005] The present invention provides an encapsulating sheet that can reduce the thickness of an electronic device while preventing encapsulated electronic components from being seen through, and an electronic device in which electronic components are encapsulated using the encapsulating sheet. [Means for solving the problem]

[0006] The present invention [1] relates to an encapsulating sheet used for encapsulating flip-chip mounted electronic components, the encapsulating sheet having an encapsulating resin layer containing an epoxy resin, a phenolic resin, an inorganic filler, and a dye, the blending ratio of the dye in the encapsulating resin layer excluding the inorganic filler being 4 mass% or more and 15 mass% or less, and the thickness ratio measured by an encapsulating test consisting of the following first to fourth steps is 30% or less.

[0007] First step: Prepare a dummy substrate comprising a glass substrate and nine dummy chips, three of which are arranged at 300 μm intervals in a first direction and three of which are arranged at 300 μm intervals in a second direction perpendicular to the first direction, the nine dummy chips being square with sides of 1 mm, 200 μm thick, and joined to the glass substrate via bumps with a height of 50 μm. Second step: One sealing resin layer with thickness T1 is placed on top of the nine dummy chips, and using a vacuum laminator, the sealing resin layer is pressed toward the nine dummy chips at a vacuum degree of 1.6 kPa, a temperature of 65°C, and a pressure of 0.1 MPa for 40 seconds, thereby obtaining a laminate in which the sealing resin layer is laminated on the dummy substrate. Third step: The laminate is heated at 150° C. for 1 hour under atmospheric pressure to cure the sealing resin layer. Fourth step: The proportion (thickness ratio) of the thickness T2 of the cured product of the encapsulating resin layer on each of the nine dummy chips to the thickness T1, which is taken as 100%, is measured.

[0008] The present invention [2] includes the encapsulating sheet according to [1], which has a transmittance of 0.5% or less at a wavelength of 450 nm, a transmittance of 1.5% or less at a wavelength of 550 nm, and a transmittance of 2.7% or less at a wavelength of 650 nm.

[0009] The present invention [3] includes the encapsulating sheet according to [1] or [2], wherein the tensile storage modulus at 25° C. of the encapsulating resin layer after curing is 9 GPa or more and 17 GPa or less.

[0010] The present invention [4] includes an electronic device comprising a flip-chip mounted electronic component and an encapsulating layer that encapsulates the electronic component, the encapsulating layer being a cured product of the encapsulating resin layer of any one of the encapsulating sheets [1] to [3]. Effect of the Invention

[0011] According to the encapsulating sheet of the present invention, the blending ratio of the dye in the encapsulating resin layer excluding the inorganic filler is 4 mass% or more and 15 mass% or less, and the thickness ratio measured by the encapsulating test consisting of the above-mentioned first to fourth steps is 30% or less. Therefore, when the electronic components are encapsulated, the thickness of the cured product of the encapsulating resin layer on the electronic components can be made thin, and the encapsulated electronic components can be prevented from being seen through. As a result, the electronic device can be made thinner, and an electronic device with excellent design can be obtained. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view of an electronic device as one embodiment of the present invention manufactured using an encapsulating sheet as one embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the encapsulating sheet. [Diagram 3] FIG. 3 is a perspective view of a dummy substrate used in a sealing test. [Figure 4] Figures 4A to 4C are explanatory diagrams for explaining the sealing test, where Figure 4A shows the state in which the sealing resin layer is placed on the dummy chip in the second step, Figure 4B shows the state in which the sealing resin layer is pressed toward the dummy chip using a vacuum laminator in the second step, and Figure 4C shows the third step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <Electronic equipment> An electronic device 10 according to one embodiment of the present invention, which is manufactured using an encapsulating sheet 1 according to one embodiment of the present invention, will be described with reference to Fig. 1. The electronic device 10 includes a substrate 11, an electronic component 12, and an encapsulating layer 13.

[0014] [substrate] The substrate 11 is, for example, a rigid substrate. The substrate 11 has a circuit pattern (not shown). The circuit pattern has terminals to be connected to the electronic components 12 and wiring extending from the terminals.

[0015] [Electronic components] The electronic component 12 is flip-chip mounted on the substrate 11 via a plurality of bumps B. For example, a plurality of electronic components 12 may be provided on the substrate 11. The plurality of electronic components 12 are spaced apart from each other. When the electronic component 12 is mounted on the substrate 11, the electronic component 12 is disposed away from the substrate 11. When the electronic component 12 is mounted on the substrate 11, the plurality of bumps B are disposed between the substrate 11 and the electronic component 12. Examples of the electronic component 12 include an imaging element, a surface acoustic wave (SAW) device, and an IC chip.

[0016] The electronic component 12 has electrodes (not shown). The electrodes are electrically connected to terminals via bumps B.

[0017] The bump B is provided on the electronic device 10. A plurality of bumps B may be provided for one electronic component 12. The plurality of bumps B are spaced apart from one another. Examples of the material of the bumps B include metal.

[0018] [Sealing layer] The sealing layer 13 seals the electronic components 12 mounted on the substrate 11. In this embodiment, the sealing layer 13 seals the electronic components 12 while leaving a space between the substrate 11 and the electronic components 12. Sealing the electronic components 12 while leaving a space between the substrate 11 and the electronic components 12 is defined as hollow sealing. By hollow sealing, the electronic components 12 can be sealed without the sealing layer 13 coming into contact with the surface S1 of the electronic components 12 on the substrate 11 side. Note that the sealing of the electronic components 12 is not limited to hollow sealing. The sealing layer 13 may be filled in the space between the substrate 11 and the electronic components 12.

[0019] <Sealing sheet> The encapsulating sheet 1 according to one embodiment of the present invention will be described with reference to FIGS. 2 to 4C.

[0020] The encapsulating sheet 1 shown in FIG. 2 is used to encapsulate an electronic component 12 (see FIG. 1) in the production of the above-described electronic device 10 (see FIG. 1). That is, the encapsulating sheet 1 is used to encapsulate the flip-chip mounted electronic component 12. The electronic component 12 is encapsulated using, for example, a vacuum laminator. The encapsulating sheet 1 includes an encapsulating resin layer 2. The encapsulating sheet 1 includes a release liner 3 as necessary. The encapsulating sheet 1 may not include the release liner 3 and may be composed of only the encapsulating resin layer 2.

[0021] [Sealing resin layer] The encapsulating resin layer 2 has thermosetting properties. The encapsulating resin layer 2 is in a semi-cured state (B-stage state). The encapsulating resin layer 2 is softened by heating and then cured. The encapsulating layer 13 (see FIG. 2) of the electronic device 10 is a cured product of the encapsulating resin layer 2 (completely cured state, C-stage state).

[0022] [Physical properties of encapsulating resin layer] There are no limitations on the thickness of the encapsulating resin layer 2. For example, the thickness of the encapsulating resin layer 2 is thinner than the thickness of the electronic components 12. The thickness of the encapsulating resin layer 2 may be thicker than the thickness of the electronic components 12.

[0023] The encapsulating resin layer 2 has a thickness of, for example, 10 μm or more, preferably 50 μm or more, and for example, 1000 μm or less, preferably 500 μm or less.

[0024] The degree to which thickness T of sealing layer 13 on surface S2 of electronic component 12 can be reduced can be evaluated by a "thickness ratio" that can be measured by the following sealing test.

[0025] The sealing test consists of steps 1 to 4. First, as shown in FIG. 3, in the first step, a dummy substrate D is prepared. The dummy substrate D includes a glass substrate S and nine dummy chips C. The nine dummy chips C are arranged in groups of three at intervals of 300 μm in a first direction, and in groups of three at intervals of 300 μm in a second direction perpendicular to the first direction. Each of the nine dummy chips C is a square with sides of 1 mm and a thickness of 200 μm. Each of the nine dummy chips C is bonded to the glass substrate S via a bump B with a height of 50 μm. 3 and 4A, in a second step, one sealing resin layer 2 having a thickness T1 (100 μm) is placed on the nine dummy chips C. Then, using a vacuum laminator, the sealing resin layer 2 is pressed toward the nine dummy chips C at a vacuum degree of 1.6 kPa, a temperature of 65° C., and a pressure of 0.1 MPa for 40 seconds. As a result, a laminate 20 in which the sealing resin layer 2 is laminated on the dummy substrate D is obtained, as shown in FIG. 4B. Next, as shown in FIG. 4C, in a third step, the laminate 20 is heated at 150° C. for 1 hour under atmospheric pressure to cure the encapsulating resin layer 2. Then, in the fourth step, the ratio (hereinafter referred to as the thickness ratio) of the thickness T2 (see Figure 4C) of the cured product (sealing layer 13) of the sealing resin layer 2 on each of the nine dummy chips C to the thickness T1 of the sealing resin layer 2 before heat pressing is measured. In the fourth step, the total thickness T0 of the obtained test piece is measured, and the thickness T of the glass substrate S is calculated from the measured total thickness T0. S The value obtained by subtracting the thickness of the dummy chip C (200 μm) and the height of the bump B (50 μm) from the thickness T2.

[0026] The thickness ratio is 30% or less, preferably less than 28%, and more preferably 25% or less.

[0027] If the thickness ratio is equal to or less than the above upper limit, the thickness T (see FIG. 1) of the sealing layer 13 on the surface S2 of the electronic component 12 can be made thin, and the electronic device 10 can be made thinner.

[0028] The thickness ratio is, for example, 5% or more, preferably 10% or more, more preferably 15% or more, still more preferably 20% or more, and particularly preferably 22% or more.

[0029] If the thickness ratio is equal to or greater than the above lower limit, the surface S2 (see FIG. 1) of the electronic component 12 can be reliably covered.

[0030] The transmittance of the encapsulating sheet 1 at a wavelength of 450 nm is, for example, less than 0.6%, preferably 0.5% or less, more preferably 0.3% or less, and for example, more than 0.0%, preferably 0.1% or more, more preferably 0.2% or more.

[0031] The transmittance of the encapsulating sheet 1 at a wavelength of 550 nm is, for example, less than 1.8%, preferably 1.5% or less, more preferably 1.0% or less, further preferably 0.8% or less, particularly preferably 0.6% or less. Also, for example, it is more than 0.0%, preferably 0.1% or more, more preferably 0.2% or more.

[0032] The transmittance of the encapsulating sheet 1 at a wavelength of 650 nm is, for example, less than 4.1%, preferably 2.7% or less, more preferably 2.0% or less, further preferably 1.2% or less, particularly preferably 0.6% or less. Also, for example, it is more than 0.0%, preferably 0.1% or more, more preferably 0.3% or more.

[0033] The transmittance at each of the above wavelengths is a value measured when the thickness of the encapsulating sheet 1 was set to 20 μm.

[0034] When the transmittance of the encapsulating sheet 1 at each of the above-mentioned wavelengths is equal to or less than the above-mentioned lower limit, the encapsulated electronic components 12 can be prevented from being seen through, and the design of the electronic device 10 is excellent.

[0035] The method for measuring the transmittance will be described in the Examples section below.

[0036] The tensile storage modulus of the cured encapsulating resin layer 2 at 25° C. (hereinafter referred to as the tensile storage modulus after curing) is, for example, 7 GPa or more, preferably 9 GPa or more, more preferably 11 GPa or more, and further preferably 13 GPa or more.

[0037] If the tensile storage modulus after curing is equal to or greater than the lower limit, the electronic components 12 and bumps B can be protected by the rigidity of the sealing layer 13 (see FIG. 1).

[0038] The tensile storage modulus after curing is, for example, 20 GPa or less, preferably 17 GPa or less, and more preferably 16 GPa or less. If the tensile storage modulus after curing is equal to or less than the upper limit value, warping of a workpiece obtained through the curing process (e.g., a substrate having multiple electronic component chips sealed with a sealing resin sheet) can be reduced.

[0039] The encapsulating resin layer 2 contains a resin component, an inorganic filler, and a dye, and optionally contains an additive.

[0040] <Resin component> The resin component is a component that becomes the base resin of the sealing layer 13 (see FIG. 1). The resin component contains an epoxy resin and a phenol resin as thermosetting resins. That is, the sealing resin layer 2 contains an epoxy resin and a phenol resin. The resin component contains a thermoplastic resin and a silane coupling agent as necessary. The resin component preferably consists of only an epoxy resin, a phenol resin, a thermoplastic resin, and a silane coupling agent.

[0041] The blending ratio of the resin component in the encapsulating resin layer 2 is, for example, 13.0 mass % or more, preferably 13.5 mass % or more, and more preferably 14.0 mass % or more.

[0042] When the blending ratio of the resin component in the encapsulating resin layer 2 is equal to or more than the above-mentioned lower limit, the thickness ratio can be adjusted to equal to or less than the above-mentioned upper limit.

[0043] The blending ratio of the resin component in the encapsulating resin layer 2 is, for example, 30 mass % or less, preferably 20 mass % or less, and more preferably 16 mass % or less.

[0044] When the blending ratio of the resin component in the encapsulating resin layer 2 is equal to or less than the above upper limit, the amount of the inorganic filler in the encapsulating resin layer 2 can be secured.

[0045] [Epoxy resin] The epoxy resin provides rigidity to the sealing layer 13 (see FIG. 1).

[0046] Examples of the epoxy resin include bifunctional epoxy resins having two epoxy groups, and polyfunctional epoxy resins having three or more epoxy groups. 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. The epoxy resin is preferably a bifunctional epoxy resin, more preferably a bisphenol F type epoxy resin.

[0047] The epoxy equivalent of the epoxy resin is, for example, 100 g / eq or more, preferably 150 g / eq or more.The epoxy equivalent of the epoxy resin is, for example, 500 g / eq or less, preferably 250 g / eq or less.

[0048] The mixing ratio of the epoxy resin in the resin component is, for example, 45 mass % or more, preferably 50 mass % or more, and for example, 60 mass % or less, preferably 55 mass % or less.

[0049] The mixing ratio of the epoxy resin in the sealing resin layer 2 is, for example, 6 mass% or more, preferably 7 mass% or more, and for example, 12 mass% or less, preferably 10 mass% or less, and more preferably 8 mass% or less.

[0050] As long as the encapsulating resin layer 2 that satisfies the above-mentioned thickness ratio and the blending ratio of the dye described below can be obtained, the type and blending ratio of the epoxy resin are not limited to the above-mentioned examples and numerical ranges.

[0051] [Phenol resin] The phenolic resin functions as a curing agent for curing the epoxy resin. Examples of the phenolic resin include novolac-type phenolic resin, triphenylmethane-type phenolic resin, and phenol-aralkyl resin. The phenolic resin can be used alone or in combination of two or more. The phenolic resin is preferably a novolac-type phenolic resin and / or a triphenylmethane-type phenolic resin, more preferably a combination thereof.

[0052] The average hydroxyl equivalent of the phenol resin is, for example, 50 g / eq or more, preferably 80 g / eq or more.The average hydroxyl equivalent of the phenol resin is, for example, 250 g / eq or less, preferably 150 g / eq or less.

[0053] When a novolac type phenolic resin and a triphenylmethane type phenolic resin are used in combination, the ratio of the triphenylmethane type phenolic resin to 100 parts by mass of the novolac type phenolic resin is, for example, 300 parts by mass or more, preferably 350 parts by mass or more, and for example, 500 parts by mass or less, preferably 450 parts by mass or less, and more preferably 400 parts by mass or less.

[0054] The ratio of the phenol resin to 100 parts by mass of the epoxy resin is, for example, 40 parts by mass or more, preferably 50 parts by mass or more, and for example, 65 parts by mass or less, preferably 55 parts by mass or less.

[0055] The mixing ratio of the phenol resin in the resin component is, for example, 20 mass % or more, preferably 25 mass % or more, and for example, 35 mass % or less, preferably 30 mass % or less.

[0056] The mixing ratio of the phenol resin in the sealing resin layer 2 is, for example, 3.0 mass % or more, preferably 3.5 mass % or more, and for example, 5.0 mass % or less, preferably 4.5 mass % or less, and more preferably 4.1 mass % or less.

[0057] As long as the encapsulating resin layer 2 that satisfies the above-mentioned thickness ratio and the blending ratio of the dye described below can be obtained, the type and blending ratio of the phenol resin are not limited to the above-mentioned examples and numerical ranges.

[0058] [Thermoplastic resin] The thermoplastic resin imparts flexibility (and thermoplasticity) to the sealing layer 13 (see FIG. 1).

[0059] Examples of thermoplastic resins include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin, phenoxy resin, acrylic resin, saturated polyester resin, polyamideimide resin, fluororesin, and styrene-isobutylene-styrene block copolymer. The thermoplastic resins can be used alone or in combination of two or more.

[0060] In order to ensure compatibility between the epoxy resin and the phenol resin and the thermoplastic resin, the thermoplastic resin is preferably an acrylic resin.

[0061] 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 (copolymerizable 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.

[0062] Examples of the alkyl group of the (meth)acrylic acid alkyl ester include alkyl groups having a carbon number of 1 to 6. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an isobutyl group, a pentyl group, and a hexyl group.

[0063] Examples of copolymerizable monomers include carboxyl group-containing monomers, acid anhydride monomers, glycidyl group-containing monomers, hydroxyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, and acrylonitrile. Examples of carboxyl group-containing monomers include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of acid anhydride monomers include maleic anhydride and itaconic anhydride. Examples of glycidyl group-containing monomers include glycidyl acrylate and glycidyl methacrylate. Examples of hydroxyl group-containing monomers include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl acrylate, 8-hydroxyoctyl methacrylate, 10-hydroxydecyl acrylate, 10-hydroxydecyl methacrylate, 12-hydroxylauryl acrylate, and 12-hydroxylauryl methacrylate. Examples of sulfonic acid group-containing monomers include styrene sulfonic acid, allyl sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, acrylamidopropanesulfonic acid, methacrylamidepropanesulfonic acid, sulfopropyl acrylate, sulfopropyl methacrylate, acryloyloxynaphthalenesulfonic acid, and methacryloyloxynaphthalenesulfonic acid. Examples of phosphoric acid group-containing monomers include 2-hydroxyethyl acryloyl phosphate. Only one type of copolymerizable monomer may be used, or two or more types may be used in combination. Examples of copolymerizable monomers include carboxyl group-containing monomers.

[0064] The glass transition temperature (Tg) of the thermoplastic resin is, for example, −70° C. or higher. The glass transition temperature of the thermoplastic resin is, for example, 0° C. or lower, preferably −5° C. or lower. The glass transition temperature (Tg) of a thermoplastic resin can be determined by the following Fox formula (theoretical value). The Fox formula is a relational expression between the glass transition temperature Tg of a polymer and the glass transition temperature Tgi of a homopolymer of the monomer that constitutes the polymer. Fox formula 1 / (273+Tg)=Σ[Wi / (273+Tgi)] In the above Fox formula, Tg represents the glass transition temperature (°C) of a polymer, Wi represents the weight fraction of monomer i constituting the polymer, and Tgi represents the glass transition temperature (°C) of a homopolymer formed from monomer i. For the glass transition temperature of homopolymers, literature values ​​can be used, and for example, the glass transition temperatures of various homopolymers are listed in "Polymer Handbook" (4th edition, John Wiley & Sons, Inc., 1999) and "New Polymer Library 7: Introduction to Synthetic Resins for Paints" (Kiyozo Kitaoka, Polymer Publishing Association, 1995). The glass transition temperature of homopolymers can also be determined by the method described in JP-A-2007-51271.

[0065] The weight average molecular weight of the thermoplastic resin is, for example, 100,000 or more, preferably 500,000 or more, and, for example, 1,500,000 or less, preferably 1,000,000 or less. The weight average molecular weight of the thermoplastic resin is measured by gel permeation chromatography (GPC) based on a standard polystyrene equivalent value.

[0066] The ratio of the thermoplastic resin to 100 parts by mass of the thermosetting resin (total amount of the epoxy resin and the phenol resin) is, for example, 11 parts by mass or more, preferably 13 parts by mass or more, more preferably 15 parts by mass or more, and for example, 24 parts by mass or less, preferably 22 parts by mass or less, more preferably 20 parts by mass or less.

[0067] The blending ratio of the thermoplastic resin in the resin component is, for example, 10 mass% or more, preferably 12 mass% or more, and for example, 18 mass% or less, preferably 16 mass% or less, and more preferably 14 mass% or less.

[0068] The blending ratio of the thermoplastic resin in the sealing resin layer 2 is, for example, 1.5 mass% or more, preferably 1.6 mass% or more, and for example, 3.0 mass% or less, preferably 2.5 mass% or less, and more preferably 2.0 mass% or less.

[0069] As long as the encapsulating resin layer 2 that satisfies the above-mentioned thickness ratio and the blending ratio of the dye described below can be obtained, the type and blending ratio of the thermoplastic resin are not limited to the above-mentioned examples and numerical ranges.

[0070] [Silane coupling agents] The silane coupling agent may, for example, be a silane coupling agent containing an epoxy group. The silane coupling agent containing an epoxy group may, for example, be glycidoxy alkyl dialkyl dialkoxy silane and glycidoxy alkyl trialkoxy silane. The silane coupling agent containing an epoxy group may, for example, be 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, for example, be 3-glycidoxy propyl trimethoxy silane.

[0071] The ratio of the silane coupling agent to 100 parts by mass of the inorganic filler is, for example, 0.1 parts by mass or more, preferably 1 part by mass or more, and for example, 10 parts by mass or less, preferably 5 parts by mass or less.

[0072] The blending ratio of the silane coupling agent in the resin component is, for example, 3 mass% or more, preferably 5 mass% or more, more preferably 7 mass% or more, and for example, 15 mass% or less, preferably 11 mass% or less, more preferably 9 mass% or less.

[0073] The mixing ratio of the silane coupling agent in the sealing resin layer 2 is, for example, 0.8 mass% or more, preferably 1.0 mass% or more, more preferably 1.1 mass% or more, and for example, 2.0 mass% or less, preferably 1.5 mass% or less, more preferably 1.3 mass% or less.

[0074] <Inorganic filler> The inorganic filler improves the strength of the sealing resin layer 2 (and the sealing layer 13). Examples of the inorganic filler include silicon compounds and silicate compounds. Examples of the silicon compounds include silica and silicon nitride. Examples of the silicate compounds include layered silicate compounds.

[0075] Examples of the layered silicate compound include smectite, kaolinite, halloysite, talc, and mica. Examples of the smectite include montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, and stevensite. Examples of the layered silicate compound include smectite, and more preferably montmorillonite.

[0076] The layered silicate compound may be an unmodified one whose surface is not modified, or may be a modified one whose surface is modified with an organic component.Preferably, the layered silicate compound has its surface modified with an organic component.Specifically, the layered silicate compound may be an organic smectite whose surface is modified with an organic component, preferably an organic bentonite whose surface is modified with an organic component.

[0077] As the organic layered silicate compound, preferably, organic smectite the surface of which is modified with ammonium, more preferably, organic bentonite the surface of which is modified with dimethyldistearylammonium, is used.

[0078] As the layered silicate compound, commercially available products can be used. For example, commercially available organic bentonite products include the Esben series (manufactured by Hojun Co., Ltd.).

[0079] Examples of inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate, and boron nitride. The inorganic fillers can be used alone or in combination of two or more.

[0080] Inorganic fillers include, for example, silica and / or organic bentonite, and more preferably, a combination thereof.

[0081] When silica and organic bentonite are used in combination, the ratio of organic bentonite to 100 parts by mass of silica is, for example, 1.0 part by mass or more, preferably 1.5 parts by mass or more, more preferably 1.8 parts by mass or more, and for example, 3.0 parts by mass or less, preferably 2.5 parts by mass or less.

[0082] 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.

[0083] The average particle size of the inorganic filler (if not substantially spherical, the average value of the maximum length) is the average particle size of silica and organic bentonite, and is, for example, 1 μm or more, and, for example, 20 μm or less, preferably 15 μm or less.

[0084] The blending ratio of the inorganic filler in the encapsulating resin layer 2 is, for example, 90 mass % or less, or preferably 85 mass % or less. When the blending ratio of the resin component in the encapsulating resin layer 2 is equal to or less than the above upper limit, the viscosity at 90°C can be reduced.

[0085] The blending ratio of the inorganic filler in the encapsulating resin layer 2 is, for example, 70 mass % or more, preferably 75 mass % or more, more preferably 78 mass % or more, and further preferably 80 mass % or more. When the blending ratio of the inorganic filler in the encapsulating resin layer 2 is equal to or more than the above lower limit, the strength of the encapsulating resin layer 2 (and the encapsulating layer 13) can be improved.

[0086] <dye> The dye can prevent the encapsulated electronic components 12 from being visible through the film.

[0087] In the present invention, dyes are distinguished from pigments, which are made of inorganic components and insoluble in organic solvents, in that they are made of organic components and are soluble in organic solvents.

[0088] The sealing resin layer 2 does not contain a pigment.

[0089] Examples of the dye include anthraquinone dyes, azo dyes, azine dyes, phthalocyanine dyes, methine dyes, oxazine dyes, quinoline dyes, indigo dyes, indigoid dyes, carbonium dyes, threne dyes, perinone dyes, perylene dyes, triarylmethane dyes, and xanthene dyes. Examples of the dye include azo dyes, and more preferably black azo dyes.

[0090] The dyes can be used alone or in combination of two or more kinds.

[0091] As the dye, commercially available products can be used. For example, commercially available black azo dyes include VALIFAST BLACK 3810 (manufactured by Orient Chemical Co., Ltd.) and OIL BLACK HBB (manufactured by Orient Chemical Co., Ltd.).

[0092] The blending ratio of the dye in the encapsulating resin layer 2 excluding the inorganic filler is 4% by mass or more, preferably 6% by mass or more, and 15% by mass or less, preferably 12% by mass or less, more preferably 10% by mass or less. If the content ratio of the dye in the encapsulating resin layer 2 is equal to or more than the above-mentioned lower limit, it is possible to prevent the encapsulated electronic component 12 from being seen through. If the content ratio of the dye in the encapsulating resin layer 2 is equal to or less than the above-mentioned upper limit, the fluidity of the encapsulating resin layer 2 is improved, and the thickness of the cured product of the encapsulating resin layer 2 on the electronic component 12 can be reduced.

[0093] The dye content in the sealing resin layer 2 is, for example, 0.3 mass% or more, preferably 0.5 mass% or more, more preferably 0.7 mass% or more, and for example, less than 2.4 mass%, preferably 2.0 mass% or less, more preferably 1.8 mass% or less.

[0094] <Additives> The additives include, for example, a curing accelerator.

[0095] [Cure accelerator] The curing accelerator is a catalyst (thermosetting catalyst) that accelerates the curing of a thermosetting resin by heating. Examples of the curing accelerator include imidazole-based curing accelerators, phosphorus-based curing accelerators, and urea-based curing accelerators. As the curing accelerator, a urea-based curing accelerator is preferably used.

[0096] These may be used alone or in combination of two or more.

[0097] Examples of the imidazole-based curing accelerator include imidazole compounds, such as 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0098] Examples of the phosphorus-based curing accelerator include organic phosphorus compounds, such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine.

[0099] Examples of the urea-based curing accelerator include aromatic urea compounds and aliphatic urea compounds. Preferred examples of the urea-based curing accelerator include aliphatic urea compounds.

[0100] Examples of aromatic urea compounds include urea compounds having a dimethylamino group and an aromatic group. Examples of aromatic urea compounds having a dimethylamino group and an aromatic group include a reaction product of toluene diisocyanate and dimethylamine.

[0101] Examples of the aliphatic urea compound include a urea compound having a dimethylamino group and an aliphatic group. Examples of the aliphatic urea compound having a dimethylamino group and an aliphatic group include a reaction product of isophorone diisocyanate and dimethylamine.

[0102] The ratio of the curing accelerator to 100 parts by mass of the resin component is, for example, 0.2 parts by mass or more, preferably 0.3 parts by mass or more, more preferably 0.4 parts by mass or more, and for example, 1.0 part by mass or less, preferably 0.7 part by mass or less.

[0103] [Manufacturing of encapsulating sheets] To produce the encapsulating sheet 1, first, the above-mentioned components are mixed in the above-mentioned ratio to prepare a thermosetting resin composition (A stage). Preferably, the above-mentioned components are thoroughly stirred. If necessary, a solvent (e.g., a ketone such as methyl ethyl ketone) is further mixed to prepare a varnish.

[0104] Next, the varnish is applied to the release liner 3, and then dried by heating. As a result, the encapsulating resin layer 2 (B stage) is formed on the release liner 3. In this way, the encapsulating sheet 1 is manufactured.

[0105] The encapsulating resin layer 2 can also be formed by kneading and extrusion molding a thermosetting resin composition without preparing a varnish.

[0106] In order to ensure the thickness of the sealing resin layer 2, a plurality of sealing resin layers 2 can be laminated (bonded together).

[0107] [Electronic device manufacturing method] The method for manufacturing an electronic device includes, for example, a preparation step and a sealing step.

[0108] {Preparation process} In the preparation step, the above-mentioned sealing resin layer and a substrate with electronic components are prepared (see FIG. 4A).

[0109] {Sealing process} In the sealing step, the electronic components in the substrate with the electronic components are sealed using a sealing resin layer (see FIG. 4B). The sealing step includes, for example, a pressing step and a heating step. The pressing step and the heating step are performed in sequence. In addition, the pressing step and the heating step may be performed simultaneously in the sealing step.

[0110] {Pressing process} In the pressing process, first, the sealing resin layer and the substrate with the electronic components are pressed together using a press (not shown). When pressing, the sealing resin layer is heated as necessary. At this time, the sealing resin layer undergoes plastic deformation in accordance with the outer shape of the electronic components. As a result, the sealing resin layer covers the electronic components.

[0111] {Heating process} Thereafter, the substrate with the electronic components and the sealing resin layer are heated, whereby the sealing resin layer is thermally cured to form a cured body (C stage) of the sealing resin layer (see FIG. 4C).

[0112] In this way, the above-mentioned electronic device is manufactured.

[0113] <Action and effect> According to the encapsulating sheet 1 of the present invention, the blending ratio of the dye in the encapsulating resin layer 2 excluding the inorganic filler is 4 mass % or more and 15 mass % or less, and the thickness ratio is 30% or less. Therefore, when the electronic component 12 is encapsulated, the thickness of the cured product of the encapsulating resin layer 2 on the electronic component 12 can be made thin, and the encapsulated electronic component 12 can be prevented from being seen through. As a result, the electronic device 10 can be made thinner, and an electronic device 10 with excellent design can be obtained. EXAMPLES

[0114] 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".

[0115] The components used in the examples and comparative examples are shown below.

[0116] (1) Epoxy resin Bifunctional epoxy resin (bisphenol F type epoxy resin, product name: YSLV-80XY, manufactured by Nippon Steel Chemical Co., Ltd., epoxy equivalent: 191g / eq) (2) Phenol resin Phenolic resin A (novolac type phenolic resin, product name: LVR-8210DL, manufactured by Gun-ei Chemical Co., Ltd., hydroxyl equivalent: 104 g / eq) Phenolic resin B (triphenylmethane type phenolic resin, product name: TPM-100, manufactured by Gun-ei Chemical Industry Co., Ltd., hydroxyl group equivalent: 98 g / eq) (3)Thermoplastic resin Carboxyl group-containing acrylic acid ester copolymer (product name: HME-2006M, manufactured by Negami Chemical Industries, methyl ethyl ketone solution with a solid content of 80% by mass, weight average molecular weight: approximately 600,000, glass transition temperature: -30°C) (4) Silane coupling agents 3-Glycidoxypropyltrimethoxysilane (Product name: KBM-403, Shin-Etsu Chemical Co., Ltd.) (5) Curing accelerator Urea-based curing accelerator (aliphatic urea compound, product name: U-CAT 3513N, San-Apro Co., Ltd.) (6) Inorganic filler Silica (Product name: 20SM-C4, Admatechs, spherical silica powder, average particle size 1.8 μm, maximum particle size 10 μm) Organic bentonite (product name: Esben NX, manufactured by Hojun Co., Ltd., organic bentonite whose surface is modified with dimethyl distearyl ammonium) (7) Coloring agent Dye (product name: VALIFAST BLACK 3810, manufactured by Orient Chemical Co., Ltd.) Dye (product name: OIL BLACK HBB, manufactured by Orient Chemical Co., Ltd.) Pigment (product name: Mitsubishi Carbon Black #2600, manufactured by Mitsubishi Chemical Corporation, particle size: 13 nm) (8) Solvent Methyl Ethyl Ketone

[0117] Example 1 According to the recipe shown in Table 1, the components and the solvent were blended and mixed to prepare an encapsulating resin composition (varnish). In Tables 1 and 2, the blending ratio of the "thermoplastic resin" is a solid content converted value, and the solvent was blended so that the solid content concentration of the varnish was 70 mass % or more and 90 mass % or less. Next, the encapsulating resin composition was applied onto the surface of a release liner made of a polyethylene terephthalate film (PET film) whose surface had been subjected to a silicone release treatment. The applied encapsulating resin composition was then dried by heating at 120° C. for 2 minutes to form an encapsulating resin layer having a thickness of 50 μm on the surface of the release liner. The encapsulating resin layer thus formed was in a semi-cured state (B-stage state). Next, the two encapsulating resin layers were bonded together at 90° C. to produce an encapsulating sheet composed of an encapsulating resin layer having a thickness of 100 μm. The encapsulating sheet was also in a B-stage state.

[0118] Examples 2 to 8 and Comparative Examples 1 to 5 An encapsulating sheet was produced based on the same procedure as in Example 1. However, based on the description in Table 1, the formulation of the encapsulating sheet was changed.

[0119] <Evaluation> [exterior] In each of the Examples and Comparative Examples, the cured product of the encapsulating resin layer after the third step of the encapsulating test was visually observed from directly above. The appearance was evaluated according to the following criteria. The results are shown in Table 1. {standard} ◎: The dummy chip is not visible and is very well concealed. ○: The dummy chip is not visible and is concealed. ×: The dummy chip is visible and cannot be concealed.

[0120] [Transmittance] In each example and each comparative example, the encapsulating resin composition was applied so that the thickness of the encapsulating sheet was 20 μm, and a sample for measurement was prepared. Next, the transmittance (%) of light with wavelengths of 450 nm, 550 nm, and 650 nm was measured using the prepared sample. The transmittance was measured using a UV-Vis-Near-Infrared Spectrophotometer V-670DS (manufactured by JASCO Corporation), and the measurement wavelength range was 190 to 800 nm. The results are shown in Table 1.

[0121] [Tensile storage modulus after curing] The encapsulating resin layer obtained in each of the Examples and Comparative Examples was cured by heating for 1 hour at 150° C. A sample having a width of 5 mm and a length of 40 mm was cut out from the obtained cured product of the encapsulating resin layer.

[0122] Next, the tensile storage modulus of the obtained sample was measured under the following conditions using a dynamic viscoelasticity measuring device (product name: RSA-G2, manufactured by TA Instruments). The results are shown in Table 1. Initial chuck distance: 20mm Measurement temperature range: -10℃~260℃ Heating rate: 10℃ / min Frequency: 1Hz Dynamic strain: 0.05% Measurement mode: Tensile mode

[0123] [Thickness ratio] The thickness ratio of the encapsulating resin layer obtained in each Example and Comparative Example was measured by an encapsulation test consisting of the following first to fourth steps. The thickness ratio was calculated by the following formula. The results are shown in Table 1. Thickness ratio (%) = Thickness of cured encapsulating resin layer T2 (μm) / Thickness of encapsulating resin layer (before curing) T1 (μm) × 100 T2 = total thickness of test piece T0 - thickness of glass substrate T S -{Thickness of dummy chip (200μm)}-{Height of bump (50μm)}

[0124] First step: Prepare a dummy substrate comprising a glass substrate and nine dummy chips, three of which are arranged at 300 μm intervals in a first direction and three of which are arranged at 300 μm intervals in a second direction perpendicular to the first direction, the nine dummy chips being square with sides of 1 mm, 200 μm thick, and joined to the glass substrate via bumps with a height of 50 μm. Second step: One sealing resin layer with a thickness T1 (100 μm) is placed on top of the nine dummy chips, and using a vacuum laminator, the sealing resin layer is pressed toward the nine dummy chips at a vacuum degree of 1.6 kPa, a temperature of 65°C, and a pressure of 0.1 MPa for 40 seconds, thereby obtaining a laminate in which the sealing resin layer is laminated on the dummy substrate. Third step: The laminate is heated at 150° C. for 1 hour under atmospheric pressure to cure the sealing resin layer. Fourth step: The ratio (thickness ratio) of the thickness T2 of the cured product of the sealing resin layer on each of the nine dummy chips is measured when the thickness T1 is taken as 100%. The total thickness T0 of the obtained test piece is measured, and the thickness T of the glass substrate is calculated from the measured total thickness T0. S The value obtained by subtracting the thickness of the dummy chip (200 μm) and the height of the bump (50 μm) from the thickness T2.

[0125] [Table 1] [Explanation of symbols]

[0126] 1. Encapsulating sheet 2 Sealing resin layer 10 Electronic equipment 12 Electronic Components 13 Sealing layer

Claims

1. An encapsulating sheet used for encapsulating flip-chip mounted electronic components, Epoxy resin, Phenol resin, An inorganic filler; Dye and A sealing resin layer containing A blending ratio of the dye in the sealing resin layer excluding the inorganic filler is 4 mass% or more and 15 mass% or less, An encapsulating sheet having a thickness ratio of 30% or less as measured by an encapsulating test consisting of the following first to fourth steps: First step: Prepare a dummy substrate including a glass substrate and nine dummy chips, three of which are arranged at intervals of 300 μm in a first direction and three of which are arranged at intervals of 300 μm in a second direction perpendicular to the first direction, the nine dummy chips being square with sides of 1 mm, 200 μm thick, and joined to the glass substrate via bumps with a height of 50 μm. Second step: A thickness of T １ One of the sealing resin layers is placed on the nine dummy chips, and the sealing resin layer is pressed toward the nine dummy chips using a vacuum laminator at a vacuum degree of 1.6 kPa, a temperature of 65°C, and a pressure of 0.1 MPa for 40 seconds, thereby obtaining a laminate in which the sealing resin layer is laminated on the dummy substrate. Third step: The laminate is heated at 150° C. for 1 hour under atmospheric pressure to cure the sealing resin layer. Fourth step: the thickness T １ The thickness T of the cured product of the sealing resin layer on each of the nine dummy chips when the thickness T is 100%. ２ The ratio (thickness ratio) is measured.

2. The transmittance at a wavelength of 450 nm is 0.5% or less, The transmittance at a wavelength of 550 nm is 1.5% or less, The encapsulating sheet according to claim 1, having a transmittance of 2.7% or less at a wavelength of 650 nm.

3. The encapsulating sheet according to claim 1 , wherein the encapsulating resin layer after curing has a tensile storage modulus at 25° C. of 9 GPa or more and 17 GPa or less.

4. A flip-chip mounted electronic component; A sealing layer that seals the electronic components; Equipped with The electronic device, wherein the sealing layer is a cured product of the sealing resin layer of the sealing sheet according to any one of claims 1 to 3.

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