Sealing resin sheets and electronic component devices

Abstract

The present invention aims to provide a sealing resin sheet and an electronic component device. The sealing resin sheet is a sheet used to seal an electronic component chip mounted on a substrate in a state of facing the substrate with a gap between it and the substrate. It is suitable for achieving good hollow sealing even when the ratio of the mounting height of the electronic component chip to the mounting interval is large. The sealing resin sheet X of the present invention sequentially comprises a sealing resin layer 11 and a sealing resin layer 12 in the thickness direction D. The sealing resin layer 11 contains a first thermosetting resin and a first inorganic filler material, and has an average linear thermal expansion coefficient of less than 20 ppm / °C after curing. The sealing resin layer 12 contains a second thermosetting resin and a second inorganic filler material, and has an average linear thermal expansion coefficient of less than 20 ppm / °C after curing. The content ratio of the first inorganic filler material in the sealing resin layer 11 is different from the content ratio of the second inorganic filler material in the sealing resin layer 12. The thickness of the sealing resin layer 11 is in the proportion of the total thickness of the sealing resin sheet X to 0.37 to 0.82.

Description

[Technical Field]

[0001] This invention relates to a sealing resin sheet and an electronic component device. [Previous Technology]

[0002] Previously, there were cases where electronic component chips on a mounting substrate were sealed with sealing resin sheets. The sealing resin sheets were sheet-shaped sealing resin materials containing thermosetting resin.

[0003] On the other hand, as an electronic component chip, there is a known type of electronic component chip that is mounted on a mounting substrate in a state where it faces the mounting substrate with a gap between it. This type of electronic component chip is sealed with a sealing resin sheet, for example, in the following manner.

[0004] First, a sealing resin sheet of a specific thickness is pressed onto a plurality of electronic component chips (facing the substrate through gaps) using a flatbed press. The plurality of electronic component chips are bonded to the same surface of the mounting substrate and separated from each other (pressing step). Thereby, the sealing resin sheet is heated and softened, plastically deformed, and covers each electronic component chip. Then, the sealing resin sheet covering the electronic component chips is hardened by heating at a high temperature (hardening step). Thereby, a hardened resin portion is formed around each electronic component chip on the substrate, and each electronic component chip is sealed with resin. Afterwards, for example, by cutting with a blade, the hardened resin portion and the substrate are cut off together, completing the monolithic packaging of each electronic component (monolithic packaging step). Technology related to this resin sealing of electronic component chips is described, for example, in Patent Document 1 below. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2015-53470 [Summary of the Invention]

[0006] [The problem the invention aims to solve]

[0007] For the above-mentioned sealing resin sheet, it is required that during the pressurization step, it flow in a softened state under heat, and that the side opposite to the electronic component wafer (exposed side) be flattened (high flowability requirement). Furthermore, for the electronic component wafer side of the sealing resin sheet, it is required that during the curing step, the sealing resin temporarily softened by high-temperature heating does not excessively enter the gap between the mounting substrate and the electronic component wafer (low flowability requirement). Thus, the sealing resin sheet exhibits different flowability requirements during softening under heat on the electronic component wafer side and its opposite side. The sealing resin sheet described in Patent Document 1 has a laminated structure of a first resin layer (a resin layer disposed on the electronic component wafer side when sealing the electronic component wafer) and a second resin layer with different filler contents to satisfy these different requirements.

[0008] However, in the sealing resin sheet of Patent Document 1, the ratio of the thickness of the first resin layer to the thickness of the second resin layer is 0.05 to 0.3. That is, the ratio of the thickness of the first resin layer to the total thickness of the sealing resin sheet is 0.048 to 0.23. With a sealing resin sheet where the first resin layer is this thin, the greater the ratio of the mounting height (the height of the side of the electronic component wafer opposite to the substrate from the substrate surface) to the mounting interval (the distance between adjacent wafers) of the plurality of electronic component wafers on the substrate, the more easily the portion of the first resin layer covering the wafer corner (edge ​​portion) is to break during the sealing process. Specifically, the greater the mounting height of the plurality of electronic component wafers on the substrate, the thinner the first resin layer becomes after stretching during the pressurization step, and the more easily it breaks. Furthermore, the narrower the mounting interval of the plurality of electronic component wafers on the substrate, the thinner the first resin layer becomes after stretching during the pressurization step, and the more easily it breaks.

[0009] Furthermore, internal stress is generated in the sealing resin sheet (sealing resin material) that is heat-cured during the curing step. This internal stress can sometimes cause warping of the workpiece obtained after the curing step (e.g., multiple electronic component chips on a substrate are sealed by the sealing resin sheet). If the warping of the workpiece is too large, the subsequent processes after the curing step cannot be properly performed. For example, it is impossible to properly laser mark the surface of the manufactured resin seal.

[0010] This invention provides a sealing resin sheet for sealing electronic component chips mounted on a substrate in a manner that separates gaps and faces the substrate. Even when the ratio of the mounting height of the electronic component chip to the mounting gap is large, it is suitable for achieving good hollow sealing performance. This invention also provides an electronic component device in which the electronic component chip is sealed by this sealing resin sheet. [Technical Means for Solving the Problem]

[0011] The present invention [1] includes a sealing resin sheet, wherein the sealing resin sheet is provided with a first sealing resin layer and a second sealing resin layer in sequence in the thickness direction, the first sealing resin layer contains a first thermosetting resin and a first inorganic filler material, and has an average linear thermal expansion coefficient of less than 20 ppm / ℃ in the temperature range of -40℃ to glass transition temperature after curing, the second sealing resin layer contains a second thermosetting resin and a second inorganic filler material, and has an average linear thermal expansion coefficient of less than 20 ppm / ℃ in the temperature range of -40℃ to glass transition temperature after curing, the content ratio of the first inorganic filler material in the first sealing resin layer is different from the content ratio of the second inorganic filler material in the second sealing resin layer, and the ratio of the thickness of the first sealing resin layer to the total thickness of the sealing resin sheet is more than 0.37 and less than 0.82.

[0012] The sealing resin sheet can be used to seal an electronic component wafer mounted on a substrate in a state where it faces the substrate with gaps in between, via a pressurization step and a curing step. In the pressurization step, the sealing resin sheet is heated and softened with its first sealing resin layer side in contact with the electronic component wafer on the substrate, and then pressed against the substrate. In this step, the gaps are blocked along the side of the electronic component wafer by the first sealing resin layer that is in close contact with the substrate around the electronic component wafer. In the curing step, the sealing resin sheet covering the electronic component wafer is further heated to harden it. This forms a hardened resin portion around the electronic component wafer on the substrate, sealing the electronic component wafer with resin. During this sealing process, the ratio of the first inorganic filler material in the first sealing resin layer disposed on the electronic component wafer side (first side) differs from the ratio of the second inorganic filler material in the second sealing resin layer disposed on the second side opposite to the first side. This configuration is suitable for giving the first and second sealing resin layers different properties. Specifically, it is suitable for giving the second sealing resin layer high fluidity during the pressurization step to improve the flattening of the second side (exposed side) of the sealing resin sheet, while giving the first sealing resin layer low fluidity to prevent excessive penetration of the sealing resin, which is temporarily softened by high temperature during the curing step, into the gap between the substrate and the electronic component chip.

[0013] Furthermore, in the sealing resin sheet, the ratio of the thickness of the first sealing resin layer to the total thickness of the sealing resin sheet, as described above, is 0.37 or more. This configuration is suitable for suppressing breakage of the portion of the first sealing resin layer covering the corner (edge) of the wafer during the pressurization step, even when the ratio of the mounting height of the electronic component wafer to the mounting interval is large. This suppression of breakage of the first sealing resin layer is suitable for preventing a portion of the second sealing resin layer from flowing into the electronic component wafer side through the breakage portion of the first sealing resin layer. If it is assumed that the second sealing resin layer, which has a higher fluidity than the first sealing resin layer, flows in in this manner during the pressurization step, the flowing resin flows between the electronic component wafer and the first sealing resin layer, reaches the gap between the substrate and the electronic component wafer, and then excessively enters the gap. The sealing resin sheet is suitable for avoiding this defect.

[0014] In addition, in the sealing resin sheet, the ratio of the thickness of the first sealing resin layer to the total thickness of the sealing resin sheet, as described above, is 0.82 or less. This configuration is suitable for ensuring the overall fluidity of the sealing resin sheet during the pressurization step, even when the ratio of the mounting height of the electronic component chip to the mounting interval is large, so as to fill the gaps between adjacent chips with sealing resin.

[0015] Furthermore, as described above, the sealing resin sheet has an average linear thermal expansion coefficient of less than 20 ppm / °C in the temperature range of -40°C to the glass transition temperature after curing. This configuration is suitable for suppressing internal stress in the first and second sealing resin layers after curing by high-temperature heating, for example, cooling to room temperature. The suppression of internal stress in the cured first and second sealing resin layers is suitable for suppressing warping in electronic component devices that use the sealing resin sheet as resin seals. This suppression of warping is suitable for suppressing the desorption of the cured resin portion formed by the sealing resin sheet from the substrate.

[0016] The present invention [2] includes a sealing resin sheet as described in [1] above, wherein the first sealing resin layer has a thickness of 90 μm or more.

[0017] From the viewpoint of suppressing the aforementioned cracking in the first sealing resin layer during the pressurization step, this configuration is preferred.

[0018] The present invention [3] includes a sealing resin sheet as described in [1] or [2] above, wherein the first sealing resin layer has a minimum melt viscosity of 120 kPa·s or more.

[0019] This configuration is better at preventing the first sealing resin layer, which is temporarily softened by high temperature during the above-mentioned curing step, from excessively entering the gap between the substrate and the electronic component chip.

[0020] The present invention [4] includes a sealing resin sheet as described in any one of [1] to [3] above, wherein the first sealing resin layer has a minimum melt viscosity of less than 260 kPa·s.

[0021] This configuration is better in ensuring the overall fluidity of the sealing resin sheet in the above-mentioned pressurization step and in filling the gaps between adjacent wafers with the sealing resin.

[0022] The present invention [5] includes a sealing resin sheet as described in any one of [1] to [4] above, wherein a third sealing resin layer is provided between the first sealing resin layer and the second sealing resin layer, the third sealing resin layer containing a third thermosetting resin and a third inorganic filler material, and having an average linear thermal expansion coefficient of less than 20 ppm / ℃ in a temperature range of -40℃ to glass transition temperature after curing.

[0023] The sealing resin sheet has a third sealing resin layer as described above in addition to the first sealing resin layer, which is better in preventing the second sealing resin layer from flowing into the electronic component wafer side during the pressurization step.

[0024] The present invention [6] includes a sealing resin sheet as described in [5] above, wherein the third sealing resin layer is in direct contact with the first sealing resin layer, and the ratio of the total thickness of the first sealing resin layer and the thickness of the third sealing resin layer to the total thickness of the sealing resin sheet is 0.4 or more and 0.82 or less.

[0025] This configuration is better in preventing the second sealing resin layer from flowing into the electronic component wafer side during the pressurization step.

[0026] The present invention [7] includes a sealing resin sheet as described in any one of [1] to [6] above, wherein the inorganic filler content in each sealing resin layer is 75% by mass or more.

[0027] This configuration is preferable in that it achieves an average linear thermal expansion rate of less than 20 ppm / ℃ in each sealing resin layer.

[0028] The present invention [8] includes a sealing resin sheet as described in any one of [1] to [7] above, wherein the inorganic filler content in each sealing resin layer is 90% by mass or less.

[0029] This configuration is better in ensuring the required flowability of the sealing resin sheet during the pressurization step.

[0030] The present invention [9] includes an electronic component device comprising: a substrate; an electronic component wafer mounted on the substrate in a state of facing the substrate with a gap between them; and a hardened resin portion formed of a sealing resin sheet as described in any one of [1] to [8] above, which seals the electronic component wafer and the gap.

[0031] In this electronic component device, since the electronic component chip is sealed by the hardened resin portion formed by the sealing resin sheet, it is suitable to achieve good hollow sealing performance.

Implementation Method

[0033] As one embodiment of the sealing resin sheet of the present invention, the sealing resin sheet X is a sheet-shaped sealing resin material used to seal electronic component wafers such as semiconductor wafers. As shown in FIG1, it has a sealing resin layer 11 and a sealing resin layer 12 sequentially provided in the thickness direction D. Furthermore, the sealing resin sheet X extends in a direction orthogonal to the thickness direction D.

[0034] The sealing resin layer 11 is a layer formed of the first thermosetting composition. The first thermosetting composition contains a first thermosetting resin and a first inorganic filler. That is, the sealing resin layer 11 contains a first thermosetting resin and a first inorganic filler. The sealing resin layer 11 is in a semi-cured state (the state of stage B).

[0035] Examples of the first thermosetting resin include epoxy resin, silicone resin, polyurethane resin, polyimide resin, urea resin, melamine resin, and unsaturated polyester resin. These first thermosetting resins can be used alone or in combination of two or more. The content of the first thermosetting resin in the first thermosetting composition is preferably 3% by mass or more, more preferably 3.5% by mass or more. The content of the first thermosetting resin in the first thermosetting composition is preferably 30% by mass or less, more preferably 25% by mass or less.

[0036] The first thermosetting resin preferably contains an epoxy resin. Examples of epoxy resins include difunctional epoxy resins and polyfunctional epoxy resins with three or more functions. Examples of difunctional epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, modified bisphenol A type epoxy resin, modified bisphenol F type epoxy resin, and biphenyl type epoxy resin. Examples of polyfunctional epoxy resins with three or more functions include phenolic varnish type epoxy resin, cresol phenolic varnish type epoxy resin, trihydroxyphenylmethane type epoxy resin, tetraphenolic ethane type epoxy resin, and dicyclopentadiene type epoxy resin. These epoxy resins can be used alone or in combination of two or more. It is preferable to use a difunctional epoxy resin, and more preferably to use bisphenol F type epoxy resin and / or bisphenol A type epoxy resin.

[0037] The epoxy equivalent of the epoxy resin is preferably 10 g / eq or more, more preferably 50 g / eq or more, and even more preferably 100 g / eq or more. The epoxy equivalent of the epoxy resin is preferably 650 g / eq or less, more preferably 600 g / eq or less, and even more preferably 550 g / eq or less. When the first thermosetting resin contains a plurality of epoxy resins, the weighted average epoxy equivalent of the plurality of epoxy resins is preferably 10 g / eq or more, more preferably 50 g / eq or more, and even more preferably 100 g / eq or more. The weighted average epoxy equivalent is preferably 650 g / eq or less, more preferably 600 g / eq or less, and even more preferably 550 g / eq or less.

[0038] When using epoxy resin, the first thermosetting resin is preferably a phenolic resin containing a phenolic resin as a curing agent for the epoxy resin. This configuration is suitable for sealing resin sheets X to exhibit higher heat resistance and higher chemical resistance after curing, and therefore is suitable for forming sealing materials with excellent sealing reliability. Examples of phenolic resins include phenolic varnish-type phenolic resins and triphenylmethane-type phenolic resins. Examples of phenolic varnish-type phenolic resins include phenolic varnish resins, phenolic aralkyl resins, trihydroxyphenylmethane phenolic resins, cresol phenolic varnish resins, tributylphenol phenolic varnish resins, and nonylphenol phenolic varnish resins. These phenolic resins can be used alone or in combination of two or more.

[0039] In the first thermosetting composition, the amount of hydroxyl groups in the phenolic resin as a curing agent is preferably 0.7 equivalents or more, more preferably 0.9 equivalents or more, relative to the epoxy groups in the epoxy resin. In the first thermosetting composition, the amount of hydroxyl groups in the phenolic resin as a curing agent is preferably 1.5 equivalents or less, more preferably 1.2 equivalents or less, relative to the epoxy groups in the epoxy resin. Furthermore, the amount of phenolic resin as a curing agent in 100 parts by weight of epoxy resin is preferably 20 parts by weight or more, more preferably 40 parts by weight or more. The amount of phenolic resin as a curing agent in 100 parts by weight of epoxy resin is preferably 80 parts by weight or less, more preferably 60 parts by weight or less.

[0040] The first thermosetting composition preferably contains a curing accelerator. The curing accelerator is a catalyst (thermosetting catalyst) that promotes the curing of the thermosetting resin by heating. Examples of curing accelerators include imidazole compounds and organophosphorus compounds. Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazolium and 2-phenyl-4-methyl-5-hydroxymethylimidazolium. Examples of organophosphorus compounds include triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine. It is preferable to use an imidazole compound as a curing accelerator, and more preferably 2-phenyl-4,5-dihydroxymethylimidazolium. The amount of the curing accelerator relative to 100 parts by weight of the first thermosetting resin is, for example, 0.05 parts by weight or more, and, for example, 5 parts by weight or less.

[0041] Regarding the first inorganic filler material, examples include layered silicate compounds and inorganic fillers other than layered silicate compounds. The first inorganic filler material is preferably composed of layered silicate compounds and inorganic fillers other than layered silicate compounds.

[0042] The layered silicate compound is a component that causes the first thermosetting composition to exhibit hygroscopic properties and thickens the first thermosetting composition, and is dispersed in the first thermosetting composition. Examples of layered silicate compounds include bentonite, kaolinite, zeolite, talc, and mica. Examples of bentonite include montmorillonite, aluminum bentonite, chlorobenzene, saponite, lithium bentonite, zinc bentonite, and sillimanite. In terms of ease of mixing with thermosetting resins, bentonite is preferred as a layered silicate compound, and montmorillonite is even more preferred.

[0043] The layered silicate compound can be an unmodified material with an unmodified surface, or it can be a modified material with an organic component on the surface. For example, from the viewpoint of affinity with the first thermosetting resin, it is preferable to use a layered silicate compound with an organic component on the surface, more preferably to use an organo-modified bentonite with an organic component on the surface, and even more preferably to use an organo-modified bentonite with an organic component on the surface.

[0044] Examples of organic components include ammonium, imidazolium, pyridinium, phosphonium, and other organic cations (onium ions). Examples of ammonium include dimethyldistearate ammonium, distearate ammonium, octadecylammonium, hexylammonium, octylammonium, 2-hexylammonium, dodecylammonium, and trioctylammonium. Examples of imidazolium include methylstearylimidazolium, distearate imidazolium, methylhexylimidazolium, dihexylimidazolium, methyloctylimidazolium, dioctylimidazolium, methyldodecylimidazolium, and di(dodecyl)imidazolium. Examples of pyridinium include stearylpyridinium, hexylpyridinium, octylpyridinium, and dodecylpyridinium. Examples of phosphonium include dimethyldistearylphosphonium, distearylphosphonium, octadecylphosphonium, hexylphosphonium, octylphosphonium, 2-hexylphosphonium, dodecylphosphonium, and trioctylphosphonium. The organic cation can be used alone or in combination with two or more. Ammonium is preferred as the organic cation, and dimethyldistearylammonium is even more preferred.

[0045] As an organic layered silicate compound, it is preferable to use organic bentonite with ammonium-modified surface, and more preferably to use organic bentonite with dimethyl distearate ammonium-modified surface.

[0046] The average particle size of the layered silicate compound is preferably 1 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more. The average particle size of the layered silicate compound is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 10 μm or less. The average particle size of the layered silicate compound is the median particle size in the volume-based particle size distribution (the particle size whose volume cumulative frequency reaches 50% from the small diameter side), for example, it can be determined based on the particle size distribution obtained by laser diffraction scattering (the same applies to the average particle size of other inorganic filler materials).

[0047] As a layered silicate compound, commercially available products can be used. Commercially available organo-bentonite products, for example, include the S-BEN series (manufactured by Ho Jun Corporation).

[0048] The content ratio of the layered silicate compound in the first thermosetting composition (i.e., the content ratio of the layered silicate compound in the sealing resin layer 11) is preferably 1% by mass or more, more preferably 1.2% by mass or more, and even more preferably 1.4% by mass or more. This configuration is suitable for increasing the viscosity of the sealing resin layer 11 and for the sealing resin layer 11 to exhibit a lower viscosity when subjected to pressure compared to when not subjected to pressure. From the viewpoint of avoiding excessive viscosity increase of the first thermosetting composition, the content ratio of the layered silicate compound in the first thermosetting composition is preferably 6% by mass or less, more preferably 5% by mass or less, and even more preferably 4% by mass or less.

[0049] Examples of inorganic fillers other than layered silicate compounds include silica compounds such as silicon oxide or silicon nitride (silica compounds other than layered silicate compounds), and silicate compounds other than layered silicate compounds such as orthosilicates, disilicates, and chain silicates. Examples of inorganic fillers other than layered silicate compounds include: aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, and boron nitride. These inorganic fillers can be used alone or in combination of two or more. It is preferable to use silica compounds other than layered silicate compounds as the inorganic filler, and more preferably silicon oxide.

[0050] The shape of the inorganic filler other than layered silicate compounds can be exemplified by, for example, generally spherical, generally plate-like, generally needle-like, and amorphous, with generally spherical being preferred.

[0051] The average particle size of the inorganic filler, excluding layered silicate compounds (when the inorganic filler has a shape other than approximately spherical, it is the average value of the maximum length of the inorganic filler) is preferably 0.1 μm or more, more preferably 0.5 μm or more. The average particle size is preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less.

[0052] The surface of inorganic fillers other than layered silicate compounds can be treated locally or entirely by surface treatment agents such as silane coupling agents.

[0053] The content of inorganic fillers, excluding layered silicate compounds, in the first thermosetting composition is preferably 73% by mass or more, more preferably 76% by mass or more, and even more preferably 78% by mass or more. This configuration is suitable for suppressing expansion and contraction caused by temperature changes in the sealing resin layer 11. The content ratio is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 83% by mass or less. This configuration is suitable for avoiding excessive thickening of the first thermosetting composition and ensuring the fluidity of the sealing resin layer 11 in the subsequent pressurization step.

[0054] The content ratio R1 of the first inorganic filler material in the first thermosetting composition (sealing resin layer 11) is preferably 75% by mass or more, more preferably 78% by mass or more, and even more preferably 80% by mass or more. This configuration is suitable for suppressing expansion and contraction caused by temperature changes in the sealing resin layer 11, and is preferable in achieving an average linear thermal expansion rate of 20 ppm / °C or less. The content ratio R1 is preferably 90% by mass or less, more preferably 87% by mass or less, and even more preferably 85% by mass or less. This configuration is suitable for avoiding excessive thickening of the first thermosetting composition and ensuring the fluidity of the sealing resin layer 11 in the subsequent pressurization step.

[0055] The proportion of layered silicate compound in the first inorganic filler material is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more. This proportion is preferably 8% by mass or less, more preferably 7% by mass or less, and even more preferably 6.5% by mass or less. This configuration is suitable for uniformly achieving suppression of expansion and contraction in the sealing resin layer 11 caused by temperature changes, ensuring fluidity during the pressurization step described later, and exhibiting the aforementioned hysteresis characteristics.

[0056] The first thermosetting composition may also contain other components. Examples of other components include thermoplastic resins, pigments, and silane coupling agents.

[0057] Examples of thermoplastic resins include: acrylic resins, natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-acrylate copolymers, polybutadiene resins, polycarbonate resins, thermoplastic polyimide resins, polyamide resins, phenoxy resins, saturated polyester resins (PET, etc.), polyamide-imide resins, fluoropolymers, and styrene-isobutylene-styrene block copolymers. These thermoplastic resins can be used alone or in combination of two or more.

[0058] As a thermoplastic resin, from the viewpoint of ensuring the compatibility between thermosetting resin and thermoplastic resin, acrylic resin is preferred.

[0059] As an acrylic resin, for example, a polymer of (meth)acrylic acid as a monomer component can be cited, wherein the monomer component includes alkyl (meth)acrylic acid esters having straight or branched alkyl groups and other monomers (comonomers).

[0060] Examples of alkyl groups that are alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, n-butyl, tributyl, isobutyl, pentyl, and hexyl.

[0061] Examples of comonomers include carboxyl-containing monomers, acid anhydride monomers, glycidyl-containing monomers, hydroxyl-containing monomers, sulfonic acid monomers, phosphate-containing monomers, and acrylonitrile. Examples of carboxyl-containing monomers include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and butenoic acid. Examples of acid anhydride monomers include maleic anhydride and itaconic anhydride. Examples of glycidyl-containing monomers include glycidyl acrylate and glycidyl methacrylate. Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylaurate (meth)acrylate. Examples of monomers containing sulfonic acid groups include styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamide propanesulfonic acid, (meth)acrylate sulfonyl propane, and (meth)acryloxynaphthalene sulfonic acid. Examples of monomers containing phosphate groups include 2-hydroxyethylacrylamide phosphate. These copolymerizable monomers can be used alone or in combination of two or more.

[0062] The glass transition temperature (Tg) of the thermoplastic resin is preferably above -70°C. The glass transition temperature is preferably below 0°C, and more preferably below -5°C.

[0063] Regarding the glass transition temperature (Tg) of the polymer, the theoretical value of the glass transition temperature can be obtained based on the following Fox formula. The Fox formula is a relationship between the glass transition temperature Tg of the polymer and the glass transition temperature Tgi of the homopolymer of the monomers constituting the polymer. In the following Fox formula, Tg represents the glass transition temperature (°C) of the polymer, Wi represents the weight fraction of monomer i constituting the polymer, and Tgi represents the glass transition temperature (°C) of the homopolymer formed from monomer i. Regarding the glass transition temperature of the homopolymer, literature values ​​can be used, 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 Coatings" (by Kyozo Kitaoka, Polymer Publishing Association, 1995). On the other hand, the glass transition temperature of the homopolymer of the monomer can also be determined by the method specifically described in Japanese Patent Application Publication No. 2007-51271.

[0064] Fox formula 1 / (273+Tg)=Σ[Wi / (273+Tgi)]

[0065] The weight-average molecular weight of the thermoplastic resin is preferably 100,000 or more, and more preferably 300,000 or more. The weight-average molecular weight of the thermoplastic resin is preferably 2,000,000 or less, and more preferably 1,000,000 or less. The weight-average molecular weight of the resin is determined by gel permeation chromatography (GPC) based on the conversion value of standard polystyrene.

[0066] The thermoplastic resin content in the first thermosetting composition is preferably 1% by mass or more, more preferably 2% by mass or more. The content is preferably 80% by mass or less, more preferably 60% by mass or less.

[0067] As a pigment, examples include black pigments such as carbon black. The particle size of the pigment is, for example, 0.001 μm or more, and, for example, 1 μm or less. The particle size of the pigment is the arithmetic mean diameter obtained by observing the pigment with an electron microscope. Furthermore, the content ratio of the pigment in the first thermosetting composition is, for example, 0.1% by mass or more, and, for example, 2% by mass or less.

[0068] Examples of silane coupling agents include those containing epoxy groups. Examples of epoxy-containing silane coupling agents include 3-glycidoxydialkyldialkoxysilane and 3-glycidoxyalkyltrialkoxysilane. Examples of 3-glycidoxydialkyldialkoxysilanes include 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane. Examples of 3-glycidoxyalkyltrialkoxysilanes include 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. 3-glycidoxyalkyltrialkoxysilane is preferred as a silane coupling agent, and more preferably 3-glycidoxypropyltrimethoxysilane. The content of the silane coupling agent in the first thermosetting composition is preferably 0.1% by mass or more, more preferably 1% by mass or more. This content is preferably 10% by mass or less, more preferably 5% by mass or less.

[0069] The sealing resin layer 12 is a layer formed of the second thermosetting composition. The second thermosetting composition contains a second thermosetting resin and a second inorganic filler. That is, the sealing resin layer 12 contains a second thermosetting resin and a second inorganic filler. The sealing resin layer 12 is in a semi-cured state (B-stage state).

[0070] The second thermosetting resin may be exemplified by the first thermosetting resin described above. The content of the second thermosetting resin in the second thermosetting composition is preferably 3% by mass or more, more preferably 3.5% by mass or more. The content of the second thermosetting resin in the second thermosetting composition is preferably 30% by mass or less, more preferably 25% by mass or less.

[0071] The second thermosetting resin preferably contains an epoxy resin. Examples of epoxy resins include those described above in relation to the first thermosetting composition; a difunctional epoxy resin is preferred, and more preferably, a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin is used. The preferred range of epoxy equivalent in the second thermosetting composition is the same as the preferred range of epoxy equivalent in the first thermosetting composition described above.

[0072] When epoxy resin is used as the second thermosetting resin, the second thermosetting resin is preferably a phenolic resin containing a curing agent for the epoxy resin. Examples of phenolic resins include phenolic varnish-type phenolic resins and triphenylmethane-type phenolic resins. The amount of hydroxyl groups in the phenolic resin used as a curing agent in the second thermosetting composition, which is equivalent to 1 part by weight of the epoxy groups of the epoxy resin, is the same as the amount of hydroxyl groups in the phenolic resin used as a curing agent in the first thermosetting composition, which is equivalent to 1 part by weight of the epoxy groups of the epoxy resin, as described above. Furthermore, the amount of phenolic resin used as a curing agent in the second thermosetting composition relative to 100 parts by weight of the epoxy resin is the same as the amount of phenolic resin used as a curing agent relative to 100 parts by weight of the epoxy resin, as described above, for the first thermosetting composition.

[0073] The second thermosetting composition preferably contains a curing accelerator. Examples of such curing accelerators include those described above for the first thermosetting composition. The amount of the curing accelerator relative to 100 parts by weight of the second thermosetting resin is, for example, 0.05 parts by weight or more, and, for example, 5 parts by weight or less.

[0074] As the second inorganic filler material, the first inorganic filler material described above with respect to the first thermosetting composition can be cited as an example. As the second inorganic filler material, it is preferable to use an inorganic filler other than a layered silicate compound, more preferably a silica compound other than a layered silicate compound, and even more preferably silicon oxide.

[0075] The shape of the second inorganic filler material can be, for example, substantially spherical, substantially plate-like, substantially needle-like, and amorphous, with a substantially spherical shape being preferred. The average particle size of the second inorganic filler material (when the second inorganic filler material has a shape other than substantially spherical, it is the average value of the maximum length of the second inorganic filler material) is preferably 0.1 μm or more, more preferably 0.5 μm or more. The average particle size is preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. The surface of the second inorganic filler material can be partially or entirely treated with a surface treatment agent such as a silane coupling agent.

[0076] The content ratio R2 of the second inorganic filler in the second thermosetting composition (sealing resin layer 12) is different from the content ratio R1 of the first inorganic filler in the sealing resin layer 11. The content ratio R2 is, for example, higher than the content ratio R1, or for example, lower than the content ratio R1.

[0077] The content ratio R2 of the second inorganic filler material in the second thermosetting composition, within a range different from the content ratio R1 described above, is preferably 75% by mass or more, more preferably 78% by mass or more, and even more preferably 80% by mass or more. This configuration is suitable for suppressing expansion and contraction caused by temperature changes in the sealing resin layer 12, and is preferable in achieving an average linear thermal expansion rate of 20 ppm / °C or less. The content ratio R2, within a range different from the content ratio R1 described above, is preferably 90% by mass or less, more preferably 87% by mass or less, and even more preferably 85% by mass or less. This configuration is suitable for ensuring the fluidity of the sealing resin layer 12 in the pressurization step described later.

[0078] The second thermosetting composition may also contain other components. Examples of other components include, for example, the same thermoplastic resin, pigment, and silane coupling agent as described above with respect to the first thermosetting composition.

[0079] For example, the sealing resin sheet X can be manufactured by bonding the sealing resin layer 11 and the sealing resin layer 12 after forming the sealing resin layer 11 and the sealing resin layer 12 respectively.

[0080] The sealing resin layer 11 can be formed, for example, as follows. First, the components and solvents described above for the first thermosetting composition are mixed in a specific ratio to prepare a varnish of the first thermosetting composition. Examples of solvents include methyl ethyl ketone, ethyl acetate, and toluene. Then, the varnish is applied to a substrate such as a release sheet to form a coating film, and the coating film is dried by heating. In this way, a sealing resin layer 11 having a sheet-like shape and being in a semi-cured state can be formed.

[0081] The sealing resin layer 12 can be formed, for example, as follows. First, the components and solvents described above for the second thermosetting composition are mixed in a specific ratio to prepare a varnish of the second thermosetting composition. Then, the varnish is applied to a substrate such as a release sheet to form a film, and the film is dried by heating. In this way, a sealing resin layer 12 having a sheet-like shape and in a semi-cured state can be formed.

[0082] The sealing resin sheet X can also be manufactured by forming a sealing resin layer 11 on a substrate and forming a sealing resin layer 12 on the sealing resin layer 11. Alternatively, the sealing resin sheet X can also be manufactured by forming a sealing resin layer 12 on a substrate and forming a sealing resin layer 11 on the sealing resin layer 12.

[0083] The ratio of the thickness H1 of the sealing resin layer 11 to the total thickness of the sealing resin sheet X is 0.37 or more, preferably 0.4 or more, more preferably 0.5 or more, and even more preferably 0.6 or more. That is, the ratio of the thickness H2 of the sealing resin layer 12 to the total thickness of the sealing resin sheet X is 0.63 or less, preferably 0.6 or less, more preferably 0.5 or less, and even more preferably 0.4 or less. This configuration is suitable for suppressing the breakage of the sealing resin layer 11 during the pressurization step described later.

[0084] The ratio of the thickness H1 of the sealing resin layer 11 to the total thickness of the sealing resin sheet X is 0.82 or less, preferably 0.8 or less. That is, the ratio of the thickness H2 of the sealing resin layer 12 to the total thickness of the sealing resin sheet X is 0.18 or more, preferably 0.2 or more. This configuration is suitable for ensuring the overall fluidity of the sealing resin sheet X in the pressurization step described later, and for filling the gaps between adjacent wafers with sealing resin.

[0085] The thickness of the sealing resin layer 11 is preferably 90 μm or more, more preferably 100 μm or more, and even more preferably 120 μm or more. This configuration is preferable from the viewpoint of suppressing the breakage of the sealing resin layer 11 during the pressurization step described later. The thickness of the sealing resin layer 11 is, for example, 300 μm or less, more preferably 250 μm or less, even more preferably 200 μm or less, and particularly preferably 180 μm or less. This configuration is preferable in ensuring the overall flowability of the sealing resin sheet X during the pressurization step described later, and in filling the gaps between adjacent wafers with the sealing resin.

[0086] The thickness H2 of the sealing resin layer 12 is preferably 30 μm or more, more preferably 50 μm or more, further preferably 80 μm or more, and even more preferably 100 μm or more. The thickness H2 of the sealing resin layer 12 is, for example, 300 μm or less, preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 180 μm or less.

[0087] The total thickness of the sealing resin sheet X is preferably 150 μm or more, more preferably 200 μm or more, and even more preferably 230 μm or more. The total thickness of the sealing resin sheet X is preferably 500 μm or less, more preferably 400 μm or less, even more preferably 300 μm or less, and particularly preferably 280 μm or less.

[0088] The minimum melt viscosity of the sealing resin layer 11 is preferably 120 kPa·s or higher, more preferably 150 kPa·s or higher, even more preferably 180 kPa·s or higher, and particularly preferably 200 kPa·s or higher. This configuration is better for preventing the sealing resin layer 11, which is temporarily softened by high-temperature heating during the curing step described later, from excessively penetrating (over-penetrating) the gap between the substrate and the electronic component chip. The minimum melt viscosity of the sealing resin layer can be determined by measuring the viscoelasticity of the sealing resin layer. The viscoelasticity measurement can be performed using a rheometer. For example, a "HAAKE MARS III" manufactured by Thermo Fisher Scientific can be used as a rheometer. In the measurement, the frequency is set to 1 Hz, the strain value is set to 0.005%, the temperature range is set to 50°C to 90°C, and the heating rate is set to 30°C / min. Specifically, the minimum melt viscosity can be determined by the measurement method described below with reference to the embodiments.

[0089] The minimum melt viscosity of the sealing resin layer 11 is preferably 260 kPa·s or less, more preferably 250 kPa·s or less, and even more preferably 240 kPa·s or less. This configuration is better for ensuring the overall fluidity of the sealing resin sheet X in the pressurization step described later, and for filling the gaps between adjacent wafers with the sealing resin.

[0090] The minimum melt viscosity of the sealing resin layer 12 is preferably 1 kPa·s or higher, more preferably 3 kPa·s or higher, and even more preferably 200 kPa·s or lower, and more preferably 180 kPa·s or lower. This configuration is better for ensuring the overall fluidity of the sealing resin sheet X in the pressurization step described later, and for filling the gaps between adjacent wafers with the sealing resin.

[0091] After being cured by heating at 150°C for 1 hour, the sealing resin layer 11 has an average linear thermal expansion coefficient Z1 of less than 20 ppm / °C within a temperature range of -40°C to the glass transition temperature, and the sealing resin layer 12, after being cured by heating at 150°C for 1 hour, has an average linear thermal expansion coefficient Z2 of less than 20 ppm / °C within a temperature range of -40°C to the glass transition temperature. This configuration is suitable for suppressing internal stress in the sealing resin layers 11 and 12 after being cured by high-temperature heating and then cooled to room temperature, for example, in the sealing resin sheet X. The average linear thermal expansion coefficient Z1 is preferably less than 18 ppm / °C, and more preferably less than 17 ppm / °C. The average linear thermal expansion coefficient Z2 is preferably less than 18 ppm / °C, and more preferably less than 17 ppm / °C. The average linear thermal expansion coefficient of the sealing resin layer can be measured using a thermomechanical analysis apparatus (TMA). For example, the "Q400 TMA" manufactured by TA Instruments Japan can be cited as a TMA. In the measurement, the mode is set to tensile mode, the heating rate is set to 1°C / min, the modulation condition is set to ±5.000°C / 300 seconds, and the measurement temperature range is set to -40°C to 260°C. Specifically, the average linear thermal expansion coefficient can be determined using the measurement method described below with reference to the examples.

[0092] The ratio of the average linear thermal expansion coefficient Z2 to the average linear thermal expansion coefficient Z1 is preferably 0.7 or more, more preferably 0.8 or more, and even more preferably 0.9 or more, and preferably 1.3 or less, more preferably 1.2 or less, and even more preferably 1.1 or less. This configuration is better for suppressing warping of the sealing resin sheet X after curing.

[0093] Figures 2A to 2C illustrate a method of using a sealing resin sheet X to seal an electronic component chip on a substrate.

[0094] Next, as shown in FIG2A, the workpiece W and the sealing resin sheet X are arranged between the first pressure plate P1 and the second pressure plate P2 of the flat plate press (arrangement step).

[0095] The workpiece W comprises a substrate S and a plurality of wafers 21. The substrate S is a substrate that is subsequently monolithically processed into a single mounting substrate and has a mounting surface Sa. Mounting terminals (not shown) are provided on the mounting surface Sa. The wafers 21 are electronic component wafers such as semiconductor wafers and have a main surface 21a and a side surface 21b. External connection terminals (not shown) are provided on the main surface 21a. The wafers 21 are mounted on the substrate S with the substrate S facing each other through a gap G, via bump electrodes 22. Each bump electrode 22 is located between the terminals provided on the mounting surface Sa of the substrate S and the terminals provided on the main surface 21a of the wafer 21, electrically connecting the substrate S and the wafer 21.

[0096] The mounting height of the chip 21 on the substrate S (the height of the side of the chip 21 opposite to the substrate S from the surface of the substrate S) is, for example, 200 μm or more, preferably 220 μm, and more preferably 250 μm or more. The mounting height is, for example, 400 μm or less, preferably 350 μm or less, and more preferably 300 μm or less.

[0097] The separation distance between the substrate S and the wafer 21 is, for example, 10 μm or more, preferably 15 μm or more, and more preferably 20 μm or more. The separation distance is, for example, 80 μm or less, preferably 60 mm or less, and more preferably 50 μm or less.

[0098] On the mounting surface Sa of the substrate S, a plurality of wafers 21 are mounted at intervals from each other in the surface direction. The interval (mounting interval) between adjacent wafers 21 is, for example, 50 μm or more, preferably 100 μm or more, and more preferably 200 μm or more. The interval between adjacent wafers 21 is, for example, 10 mm or less, preferably 5 mm or less, and more preferably 1 mm or less.

[0099] In this step, the workpiece W is placed on the first pressure plate P1 with its substrate S in contact with the first pressure plate P1. The sealing resin sheet X is deposited on the workpiece W with the sealing resin layer 11 in contact with the wafer 21 of the workpiece W.

[0100] Next, as shown in FIG2B, the sealing resin sheet X and the workpiece W are pressurized in the thickness direction D by the first pressure plate P1 and the second pressure plate P2 (pressurization step). Specifically, with the sealing resin layer 11 side of the sealing resin sheet X in contact with the wafer 21 on the substrate S, the sealing resin sheet X is heated and softened, and then pressed against the substrate S.

[0101] The pressurization pressure is, for example, 0.01 MPa or more, preferably 0.05 MPa or more. The pressurization pressure is, for example, 10 MPa or less, preferably 5 MPa or less. The pressurization time is, for example, 0.3 minutes or more, preferably 0.5 minutes or more. The pressurization time is, for example, 10 minutes or less, preferably 5 minutes or less. Furthermore, the heating temperature during pressurization is, for example, 40°C or more, preferably 60°C or more. The heating temperature is, for example, 100°C or less, preferably 95°C or less.

[0102] In this step, the sealing resin sheet X maintains the B-stage on one side and deforms to correspond to the shape of the wafer 21, thereby covering the side surface 21b of each wafer 21 and contacting the mounting surface Sa of the substrate S, which does not overlap with the wafer 21 when viewed from above. The gap G is blocked by the sealing resin layer 11 that is in close contact with the substrate S around the wafer 21 along the side surface 21b of the wafer 21 (the opening end of the gap G is blocked).

[0103] The sealant resin sheet X, which is allowed to deform, slightly enters the gap G between the substrate S and the wafer 21. Specifically, with the side surface 21b of the wafer 21 as a reference, the sealant resin sheet X is allowed to have an entry length L1 into the gap G.

[0104] The penetration length L1 is preferably 50 μm or less, more preferably 30 μm or less. This configuration is suitable for ensuring an area where wiring can be formed in the main surface 21a of the wafer 21, and also suitable for ensuring an area where wiring can be formed in the mounting surface Sa of the substrate S, thus contributing to the high functionality of the resin sealant. Furthermore, the penetration length L1 is preferably 0 μm or more. This configuration is suitable for properly sealing the wafer 21 and the gap G in the monolithic electronic component device that serves as a resin sealant, as described later, to prevent the gap G from opening outside the resin sealant.

[0105] Next, after the workpiece W, which has been sealed by the sealing resin sheet X, is taken out of the flatbed press, the sealing resin sheet X is heated to harden it (hardening step), as shown in FIG2C. Thereby, a hardened resin portion is formed around each wafer 21 on the substrate S, and each wafer 21 is sealed by the resin.

[0106] The heating temperature (hardening temperature) is, for example, 100°C or higher, preferably 120°C or higher. The heating temperature (hardening temperature) is, for example, 200°C or lower, preferably 180°C or lower. The heating time is, for example, 10 minutes or more, preferably 30 minutes or more. The heating time is, for example, 180 minutes or lower, preferably 120 minutes or lower.

[0107] The penetration length L2 within the void G in the hardened sealing resin sheet X is preferably 50 μm or less, more preferably 30 μm or less. This configuration is suitable for ensuring an area where wiring can be formed in the main surface 21a of the wafer 21, and also suitable for ensuring an area where wiring can be formed in the mounting surface Sa of the substrate S, thus contributing to the high functionality of the resin seal. The penetration length L2 is preferably 0 μm or more. This configuration is suitable for properly sealing the wafer 21 and the void G in the monolithic electronic component device that serves as a resin seal, as described later, to prevent the void G from opening outside the resin seal.

[0108] Subsequently, for example, by cutting with a blade, the hardened sealing resin sheet X and the substrate S are cut along a specific predetermined cutting line, completing the monolithization of the electronic component device as a resin sealant (monolithization step). The electronic component device thus obtained includes: a substrate S as a base material, a wafer 21 as an electronic component chip mounted on the substrate S in a state facing the substrate S with a gap G between them, and a hardened resin portion formed by the sealing resin sheet X and sealing the wafer 21 and the gap G.

[0109] Regarding the sealing resin sheet X, the content ratio R1 of the first inorganic filler material in the sealing resin layer 11 disposed on the wafer 21 side (first side) during the sealing process described above is different from the content ratio R2 of the second inorganic filler material in the sealing resin layer 12 disposed on the second side opposite to the first side. This configuration is suitable for making the sealing resin layer 11 and the sealing resin layer 12 exhibit different characteristics. Specifically, in the pressurization step (Fig. 2B), the sealing resin layer 12 is made to exhibit high fluidity to improve the planarization of the second side (exposed surface side) of the sealing resin sheet X. On the other hand, the sealing resin layer 11 is made to exhibit low fluidity to prevent the sealing resin, which is temporarily softened by high temperature heating in the curing step (Fig. 2C), from entering too much of the gap G between the substrate S and the wafer 21.

[0110] Furthermore, in the sealing resin sheet X, the ratio of the thickness of the sealing resin layer 11 to the total thickness of the sheet, as described above, is 0.37 or more, preferably 0.4 or more, more preferably 0.5 or more, and even more preferably 0.6 or more. This configuration is suitable for suppressing breakage of the portion of the sealing resin layer 11 covering the corner (edge ​​portion) of the wafer 21 during the pressurization step (FIG. 2B) even when the ratio of the mounting height of the wafer 21 to the mounting interval is large. This suppression of breakage of the sealing resin layer 11 is suitable for suppressing a portion of the sealing resin layer 12 from flowing into the wafer 21 side through the breakage portion of the sealing resin layer 11. If, assuming that the aforementioned inflow occurs in the sealing resin layer 12, which has a higher fluidity than the sealing resin layer 11, during the pressurization step, the flowing resin flows between the wafer 21 and the sealing resin layer 11 and reaches the gap G between the substrate S and the wafer 21, thereby potentially causing excessive entry into the gap G. The sealing resin sheet X is suitable for avoiding this defect.

[0111] In addition, the ratio of the thickness H1 of the sealing resin layer 11 to the total thickness of the sealing resin sheet X, as described above, is 0.82 or less, preferably 0.8 or less. This configuration is suitable for ensuring the overall fluidity of the sealing resin sheet X during the pressurization step (FIG. 2B) and filling the gaps between adjacent wafers 21 with sealing resin, even when the ratio of the mounting height of the wafer 21 to the mounting interval is large.

[0112] Furthermore, as described above, each sealing resin layer of the sealing resin sheet X has an average linear thermal expansion coefficient of less than 20 ppm / °C within a temperature range of -40°C to the glass transition temperature after curing. This configuration is suitable for suppressing internal stress in each sealing resin layer of the sealing resin sheet X after curing by high-temperature heating, for example, cooling to room temperature. The suppression of internal stress in each sealing resin layer after curing is suitable for suppressing warping in electronic component devices that use the sealing resin sheet X as resin seals. This suppression of warping is suitable for suppressing the detachment of the cured resin portion formed by the sealing resin sheet X from the substrate S.

[0113] As described above, the sealing resin layer 11 preferably contains a layered silicate compound. This configuration is suitable for increasing the viscosity of the sealing resin layer 11 and for the sealing resin layer 11 to exhibit a lower viscosity when subjected to pressure compared to when not subjected to pressure. The flexural properties of the sealing resin layer 11 are suitable for softening and flowing together with the sealing resin layer 12 under pressure during the pressurization step (FIG. 2B), deforming to follow the shape of the wafer 21. The increased viscosity of the sealing resin layer 11 is suitable for suppressing the decrease in viscosity of the sealing resin layer 11 due to temperature rise during the curing step (FIG. 2C) and for suppressing excessive penetration of the sealing resin into the voids G.

[0114] The sealing resin sheet X may also have at least one other sealing resin layer between the sealing resin layers 11 and 12. Figure 3 illustrates the case where the sealing resin sheet X has a sealing resin layer 13 between the sealing resin layers 11 and 12. The sealing resin layer 13 is directly in contact with the sealing resin layers 11 and 12. The sealing resin sheet X having a sealing resin layer between the sealing resin layers 11 and 12 is preferable in terms of preventing the sealing resin layer 12 from flowing into the electronic component chip side during the above-mentioned pressurization step.

[0115] The sealing resin layer 13 is a layer formed of the third thermosetting composition. The third thermosetting composition contains a third thermosetting resin and a third inorganic filler. That is, the sealing resin layer 13 contains a third thermosetting resin and a third inorganic filler. The sealing resin layer 13 is in a semi-cured state (the state of stage B).

[0116] The third thermosetting resin may be exemplified by the first thermosetting resin described above. The content of the third thermosetting resin in the third thermosetting composition is preferably 3% by mass or more, more preferably 3.5% by mass or more. The content of the third thermosetting resin in the third thermosetting composition is preferably 30% by mass or less, more preferably 25% by mass or less.

[0117] The third thermosetting resin preferably contains an epoxy resin. Examples of epoxy resins include those described above in relation to the first thermosetting composition; a difunctional epoxy resin is preferred, and more preferably, a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin is used. The preferred range of epoxy equivalent in the third thermosetting composition is the same as the preferred range of epoxy equivalent in the first thermosetting composition described above.

[0118] When epoxy resin is used as the third thermosetting resin, the third thermosetting resin is preferably a phenolic resin containing a curing agent for the epoxy resin. Examples of phenolic resins include phenolic varnish-type phenolic resins and triphenylmethane-type phenolic resins. The amount of hydroxyl groups in the phenolic resin as a curing agent in the third thermosetting composition, which is equivalent to 1 part by weight of the epoxy groups of the epoxy resin, is the same as the amount of hydroxyl groups in the phenolic resin as a curing agent in the first thermosetting composition, which is equivalent to 1 part by weight of the epoxy groups of the epoxy resin, as described above. Furthermore, the amount of phenolic resin as a curing agent in the third thermosetting composition relative to 100 parts by weight of the epoxy resin is the same as the amount of phenolic resin as a curing agent relative to 100 parts by weight of the epoxy resin, as described above for the first thermosetting composition.

[0119] The third thermosetting composition preferably contains a curing accelerator. Examples of such curing accelerators include those described above for the first thermosetting composition. The amount of the curing accelerator relative to 100 parts by weight of the third thermosetting resin is, for example, 0.05 parts by weight or more, and, for example, 5 parts by weight or less.

[0120] As the third inorganic filler material, examples may include the first inorganic filler material (layered silicate compound, inorganic filler other than layered silicate compound) described above with respect to the first thermosetting composition.

[0121] The content ratio of the layered silicate compound in the third thermosetting composition (i.e., the content ratio of the layered silicate compound in the sealing resin layer 13) is preferably 1% by mass or more, more preferably 1.2% by mass or more, and even more preferably 1.4% by mass or more. This configuration is suitable for increasing the viscosity of the sealing resin layer 13 and for the sealing resin layer 13 to exhibit a lower viscosity when subjected to pressure compared to when not subjected to pressure. From the viewpoint of avoiding excessive viscosity increase of the third thermosetting composition, the content ratio of the layered silicate compound in the third thermosetting composition is preferably 6% by mass or less, more preferably 5% by mass or less, and even more preferably 4% by mass or less.

[0122] As the inorganic filler in the third thermosetting composition, other than the layered silicate compound, it is preferable to use a silica compound other than the layered silicate compound, and more preferably, silica. Examples of the shape of this inorganic filler include approximately spherical, approximately plate-like, approximately needle-like, and amorphous shapes, with approximately spherical being preferred. The average particle size of the inorganic filler other than the layered silicate compound is the same as the average particle size of the inorganic filler other than the layered silicate compound in the first thermosetting composition described above.

[0123] The content of inorganic fillers, excluding layered silicate compounds, in the third thermosetting composition is preferably 73% by mass or more, more preferably 76% by mass or more, and even more preferably 78% by mass or more. This configuration is suitable for suppressing expansion and contraction caused by temperature changes in the sealing resin layer 13. The content ratio is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 83% by mass or less. This configuration is suitable for avoiding excessive thickening of the third thermosetting composition and ensuring the fluidity of the sealing resin layer 13 in the aforementioned pressurization step.

[0124] The content ratio R3 of the third inorganic filler material in the third thermosetting composition (sealing resin layer 13) is preferably 75% by mass or more, more preferably 78% by mass or more, and even more preferably 80% by mass or more. This configuration is better in suppressing expansion and contraction caused by temperature changes in the sealing resin layer 13, and better in achieving an average linear thermal expansion rate of 20 ppm / °C or less. The content ratio R3 is preferably 90% by mass or less, more preferably 87% by mass or less, and even more preferably 85% by mass or less. This configuration is suitable for avoiding excessive thickening of the third thermosetting composition and ensuring the fluidity of the sealing resin layer 13 in the above-mentioned pressurization step.

[0125] The proportion of layered silicate compound in the third inorganic filler material is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more. This proportion is preferably 8% by mass or less, more preferably 7% by mass or less, and even more preferably 6.5% by mass or less. These configurations are suitable for uniformly achieving suppression of expansion and contraction caused by temperature changes in the sealing resin layer 13, ensuring fluidity during the pressurization step, and exhibiting the aforementioned volatility.

[0126] The third thermosetting composition may also contain other components described above with respect to the first thermosetting composition.

[0127] The sealing resin sheet X shown in Figure 3 can be manufactured, for example, by sequentially bonding sealing resin layer 11, sealing resin layer 13 and sealing resin layer 12 after forming sealing resin layers 11, 12 and 13 respectively. Sealing resin layer 13 can be formed using the same method as described above with respect to sealing resin layers 11 and 12.

[0128] The ratio of the total thickness of the sealing resin layer H1 and the sealing resin layer 13 to the total thickness of the sealing resin sheet X is preferably 0.4 or more, more preferably 0.5 or more, and even more preferably 0.6 or more. This configuration is better in preventing the sealing resin layer 12 from flowing into the electronic component wafer side during the pressurization step described above.

[0129] The ratio of the total thickness of the sealing resin layer H1 and the sealing resin layer 13 to the total thickness of the sealing resin sheet X is 0.82 or less, preferably 0.8 or less. This configuration is suitable for ensuring the overall fluidity of the sealing resin sheet X during the above-mentioned pressurization step, and for filling the gaps between adjacent wafers with sealing resin.

[0130] The minimum melt viscosity of the sealing resin layer 13 is preferably 120 kPa·s or higher, more preferably 150 kPa·s or higher, and even more preferably 260 kPa·s or lower, and more preferably 240 kPa·s or lower. This configuration is better for ensuring the overall fluidity of the sealing resin sheet X during the above-mentioned pressurization step and for filling the gaps between adjacent wafers with the sealing resin.

[0131] After being cured by heating at 150°C for 1 hour, the sealing resin layer 13 has an average linear thermal expansion coefficient Z3 of less than 20 ppm / °C within a temperature range of -40°C to the glass transition temperature. This configuration is suitable for suppressing internal stress in the sealing resin layer 13 after it has been cured by high-temperature heating, for example, cooled to room temperature, within the sealing resin sheet X. [Example]

[0132] Hereinafter, embodiments will be shown to illustrate the present invention in more detail. The present invention is not limited to the embodiments. Furthermore, the specific values ​​of dosage (content), physical property value, parameters, etc. used in the following description can be replaced by the corresponding upper limit (defined as a value "below" or "not reached") or lower limit (defined as a value "above" or "exceeded") of the dosage (content), physical property value, parameters, etc. described in the above "Embodiments".

[0133] [Preparation Examples 1-8] The resin films of Preparation Examples 1-8 for forming a sealing resin layer were prepared as follows. First, the components were mixed according to the formulation shown in Table 1 to prepare a composition (varnish) (in Table 1, the units of the values ​​of each component are relative "parts by mass"). Then, the composition was coated on a polyethylene terephthalate film (PET film) whose surface had been treated with silicone release to form a coating film. Then, the coating film was heated and dried at 120°C for 2 minutes to form a resin film with a thickness of 50 μm on the PET film (the resin film is in the B- stage state). Furthermore, the resin film of Preparation Example 2 was also prepared as a resin film with a thickness of 40 μm, and the resin film of Preparation Example 5 was also prepared as a resin film with a thickness of 40 μm and a resin film with a thickness of 20 μm.

[0134] [Table 1] Production example 1 Production example 2 Production example 3 Production example 4 Production example 5 Production example 6 Production example 7 Production example 8 thermosetting resins Epoxy Resin E1 (EXA-4850-150) - - - - - 5.10 - - Epoxy Resin E2 (YSLV-80XY) 5.71 5.37 6.34 4.79 5.54 5.10 6.70 2.84 Epoxy Resin E3 (EPPN-501HY) - - - - 1.39 - 1.68 0.71 Phenolic resin F1 (LVR-8210DL) 0.59 0.56 0.66 1.79 3.87 - 4.68 1.98 Phenolic resin F2 (MEHC-7851SS) - - - - - 7.68 - - Phenolic resin F3 (TPM-100) 2.37 2.23 2.63 0.77 - - - - thermoplastic resin Acrylic polymer (HME-2006M) 10.50 6.18 14.86 8.46 4.50 16.55 5.35 2.53 Inorganic filler materials Organic bentonite (S-BEN NX) 1.40 1.40 1.45 1.75 - - - - Silicon oxide particles (FB-8SM) 34.02 34.86 34.37 34.86 44.77 34.13 43.17 48.50 Second silicon oxide particles (SC220G-SMJ) 22.68 23.24 22.91 23.24 24.11 18.38 23.25 26.11 hardening accelerator Imidazole compounds (2PHZ-PW) 0.04 0.04 0.05 0.03 0.13 0.08 0.15 0.07 Silane coupling agent 3-Glycidoxypropyltrimethoxysilane (KBM-403) 0.85 0.87 0.86 0.87 1.03 0.79 1.00 1.12 pigment Carbon Black #20 0.23 0.20 0.27 0.20 0.26 0.44 0.30 0.17 solvent Methyl ethyl ketone 21.60 25.06 15.61 23.23 14.40 11.76 13.72 15.97 Thickness (μm) 50 50 50 50 50 50 50 50

[0135] The components used in Examples 1-8 are as follows: Epoxy Resin E1: "EPICLON EXA-4850-150" manufactured by DIC Corporation (Bisphenol A type epoxy resin, molecular weight 900, epoxy equivalent 450 g / eq, liquid at room temperature) Epoxy Resin E2: "YSLV-80XY" manufactured by Nippon Steel Chemical Co., Ltd. (Bisphenol F type epoxy resin, high molecular weight epoxy resin, epoxy equivalent 191 g / eq, solid at room temperature, softening point 80℃) Epoxy Resin E3: "EPPN-501HY" manufactured by Nippon Chemical Co., Ltd. (Multifunctional epoxy resin, epoxy equivalent 169 g / eq, solid at room temperature, softening point 60℃) Phenolic Resin F1: "LVR-8210DL" manufactured by Kunei Chemical Co., Ltd. (Phenolic varnish type phenolic resin, latent curing agent, hydroxyl equivalent 104) Phenolic Resin F2: MEHC-7851SS (phenolic aralkyl resin, latent curing agent, hydroxyl equivalent 201-220 g / eq, solid at room temperature, softening point 64-85℃) manufactured by Meiwa Chemical Co., Ltd. Phenolic Resin F3: TPM-100 (triphenylmethane type phenolic resin, latent curing agent, hydroxyl equivalent 98 g / eq, solid at room temperature, softening point 108.2℃) manufactured by Chung-Ying Chemical Co., Ltd. Acrylic Resin (Acrylic Polymer): HME-2006M (carboxyl-containing acrylic resin, acid value 32 mgKOH / g, weight average molecular weight 1.29 million, glass transition temperature (Tg) -13.9℃, 20% by mass methyl ethyl ketone solution) manufactured by Genjo Industrial Co., Ltd. Silane coupling agent: "KBM-403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. Layered silicate compound: "S-BEN NX" (organo-modified bentonite with dimethyl distearate ammonium surface treatment) manufactured by Ho Jun Co., Ltd. First silicate particle: "FB-8SM" (spherical silicate particles, average particle size 7.0 μm, no surface treatment) manufactured by DENKA Co., Ltd. Second silicate particle: "SC220G-SMJ" (spherical silicate particles, average particle size 0.5 μm) manufactured by Admatechs Co., Ltd. The silicate coupling agent used in the surface treatment was obtained by surface treatment with 3-methylacryloxypropyltrimethoxysilane ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.) (the silicate coupling agent used in the surface treatment was 1 part by mass relative to 100 parts by mass of silicate particles). Curing accelerator: "2PHZ-PW" (2-phenyl-4,5-dihydroxymethylimidazolium) manufactured by Shikoku Chemical Industry Co., Ltd. Pigment: Carbon black: #20 manufactured by Mitsubishi Chemical Co., Ltd., with an average particle size of 50 nm. Solvent: Methyl ethyl ketone.

[0136] [Examples 1-9 and Comparative Examples 1-5] Each sealing resin sheet of Examples 1-9 and Comparative Examples 1-5 was prepared. Details are as follows.

[0137] In the fabrication of the sealing resin sheet of Example 1, two resin films (50 μm thick) from Example 1 were laminated to form a first sealing resin layer (100 μm thick), and three resin films (50 μm thick) from Example 5 were laminated to form a second sealing resin layer (150 μm thick). The first and second sealing resin layers were then laminated together. The lamination temperature was 80°C (the same applies to the lamination process described below).

[0138] In the fabrication of the sealing resin sheet of Example 2, three resin films (50 μm thick) of Example 1 were laminated together to form a first sealing resin layer (150 μm thick), two resin films (50 μm thick) of Example 5 were laminated together to form a second sealing resin layer (100 μm thick), and the first and second sealing resin layers were laminated together.

[0139] In the fabrication of the sealing resin sheet of Example 3, four resin films (thickness 50 μm) of Example 1 were laminated to form a first sealing resin layer (thickness 200 μm), and a resin film (thickness 50 μm) of Example 5 was prepared as a second sealing resin layer, and the first and second sealing resin layers were laminated together.

[0140] In the fabrication of the sealing resin sheet of Example 4, two resin films (50 μm thick) of Example 2 were laminated to form a first sealing resin layer (100 μm thick), and three resin films (50 μm thick) of Example 5 were laminated to form a second sealing resin layer (150 μm thick). The first and second sealing resin layers were then laminated together.

[0141] In the fabrication of the sealing resin sheet of Example 5, three resin films (50 μm thick) of Example 2 were laminated to form a first sealing resin layer (150 μm thick), two resin films (50 μm thick) of Example 5 were laminated to form a second sealing resin layer (100 μm thick), and the first and second sealing resin layers were laminated together.

[0142] In the fabrication of the sealing resin sheet of Example 6, four resin films (50 μm thick) of Example 2 were laminated to form a first sealing resin layer (200 μm thick), and a resin film (50 μm thick) of Example 5 was prepared as a second sealing resin layer, and the first and second sealing resin layers were laminated together.

[0143] In the fabrication of the sealing resin sheet of Example 7, two resin films (40 μm thick) of Example 2 were laminated to form a first sealing resin layer (80 μm thick), and three resin films (40 μm thick) of Example 5 were laminated to form a second sealing resin layer (120 μm thick). The first and second sealing resin layers were then laminated together.

[0144] In the fabrication of the sealing resin sheet of Example 8, three resin films (50 μm thick) of Example 2 were laminated to form a first sealing resin layer (150 μm thick), two resin films (50 μm thick) of Example 8 were laminated to form a second sealing resin layer (100 μm thick), and the first and second sealing resin layers were laminated together.

[0145] In the fabrication of the sealing resin sheet of Example 9, two resin films (50 μm thick) of Example 2 were laminated to form a first sealing resin layer (100 μm thick). The resin film (50 μm thick) of Example 1 was prepared as the third sealing resin layer. Two resin films (50 μm thick) of Example 5 were laminated to form a second sealing resin layer (100 μm thick). The first, third and second sealing resin layers were laminated in sequence.

[0146] In the fabrication of the sealing resin sheet of Comparative Example 1, two resin films (50 μm thick) of Fabrication Example 1 were laminated together to form a first sealing resin layer (100 μm thick), and a resin film (20 μm thick) of Fabrication Example 5 was prepared as a second sealing resin layer, and the first and second sealing resin layers were laminated together.

[0147] In the fabrication of the sealing resin sheet of Comparative Example 2, two resin films (40 μm thick) of Fabrication Example 2 were laminated to form a first sealing resin layer (80 μm thick), and four resin films (50 μm thick) of Fabrication Example 5 were laminated to form a second sealing resin layer (200 μm thick). The first and second sealing resin layers were then laminated together.

[0148] In the fabrication of the sealing resin sheet of Comparative Example 3, two resin films (50 μm thick) of Fabrication Example 3 were laminated to form a first sealing resin layer (100 μm thick), and three resin films (50 μm thick) of Fabrication Example 6 were laminated to form a second sealing resin layer (150 μm thick), and the first and second sealing resin layers were laminated together.

[0149] In the fabrication of the sealing resin sheet of Comparative Example 4, two resin films (50 μm thick) of Fabrication Example 4 were laminated to form a first sealing resin layer (100 μm thick), and three resin films (50 μm thick) of Fabrication Example 6 were laminated to form a second sealing resin layer (150 μm thick), and the first and second sealing resin layers were laminated together.

[0150] In the fabrication of the sealing resin sheet of Comparative Example 5, two resin films (50 μm thick) of Fabrication Example 3 were laminated to form a first sealing resin layer (100 μm thick), and three resin films (50 μm thick) of Fabrication Example 7 were laminated to form a second sealing resin layer (150 μm thick), and the first and second sealing resin layers were laminated together.

[0151] <Minimum Melt Viscosity> The minimum melt viscosity of the first sealing resin layer of each sealing resin sheet in Examples 1 to 9 and Comparative Examples 1 to 5 was measured in the following manner.

[0152] First, for each of the sealing resin sheets of Examples 1-9 and Comparative Examples 1-5, 20 sheets of the above-mentioned resin film (thickness 50 μm) forming the first sealing resin layer were laminated to prepare a test sample film (thickness 1 mm). Next, the viscoelasticity of the sample film was measured. In this measurement, a rheometer (trade name "HAAKE MARS III", manufactured by Thermo Fisher Scientific) was used. The sample film was inserted between a heating plate in the device and a parallel plate (diameter 8 mm) arranged parallel to the heating plate, with a plate gap of 0.8 mm. Then, the viscosity of the sample film was measured under the conditions of a frequency of 1 Hz, a strain value of 0.005%, a temperature range of 50°C to 90°C, and a heating rate of 30°C / min. The viscosity at the temperature showing the lowest viscosity within the measurement temperature range is shown as the lowest melt viscosity (kPa·s) in Tables 2-4.

[0153] <Average linear thermal expansion rate> The average linear thermal expansion rate of each sealing resin layer of each sealing resin sheet of Examples 1-9 and Comparative Examples 1-5 after curing was studied.

[0154] First, a sheet segment (4.5 mm wide × 16 mm long) is cut from the self-sealing resin sheet. Next, the sheet segment is hardened by heating at 150°C for 1 hour. Then, the hardened sealing resin layer (first sealing resin layer, second sealing resin layer, or third sealing resin layer) is retained on the hardened sheet segment and the hardened sealing resin layer (excluding the first sealing resin layer, second sealing resin layer, or third sealing resin layer) is removed by mechanical grinding. A grinding machine (product name "EcoMet250", manufactured by BUEHLER) is used for mechanical grinding. Then, the linear thermal expansion coefficient (TMA measurement) of the hardened sealing resin layer prepared in the above manner is measured using a thermomechanical analysis (TMA) apparatus under the following conditions. Based on the measurement results, the glass transition temperature and the average linear thermal expansion coefficient within the temperature range of -40°C to the aforementioned glass transition temperature are determined for the hardened sealing resin layer. The average linear thermal expansion coefficients Z1, Z2, and Z3 (ppm / ℃) of the first to third sealing resin layers after curing are shown in Tables 2 to 4.

[0155] (Measurement Conditions) Thermomechanical Analysis Apparatus (TMA): Q400 TMA, manufactured by TA Instruments Japan. Mode: Tensile mode. Heating rate: 1℃ / min. Modulation: ±5.000℃ / 300 seconds. Measurement temperature range: -40℃ to 260℃.

[0156] <Evaluation of Ingress Length> The hollow sealing performance of each sealing resin sheet in Examples 1-9 and Comparative Examples 1-5 was studied. Details are as follows.

[0157] First, as shown in FIG4A, a sample sheet X' (10 mm longitudinally × 10 mm transversely) is prepared from the sealing resin sheet of each embodiment and each comparative example. The sample sheet X' cut from the sealing resin sheet of Examples 1 to 8 and Comparative Examples 1 to 5 is provided with a first sealing resin layer 11 and a second sealing resin layer 12 in the thickness direction. The sample sheet X' cut from the sealing resin sheet of Example 9 is provided with a first sealing resin layer 11, a third sealing resin layer (not shown), and a second sealing resin layer 12 in the thickness direction.

[0158] On the other hand, a dummy wafer mounting substrate is prepared as a workpiece W. The dummy wafer mounting substrate includes a glass substrate S and a plurality of dummy wafers 21' (3 mm × 3 mm × 250 μm thick). The dummy wafers 21' are positioned opposite the substrate S through a gap G and are bonded to the substrate S via bump electrodes 22. The mounting height of the dummy wafers 21' is 300 μm. The mounting spacing of the dummy wafers 21' is 300 μm. The length in the gap G from the substrate S to the dummy wafers 21' (the separation distance between the substrate S and the dummy wafers 21') is 50 μm.

[0159] Then, as shown in FIG4B, the above workpiece W and sample sheet X' are placed between the first pressure plate P1 and the second pressure plate P2 of the flat press.

[0160] Then, as shown in FIG4C, the dummy chip 21' on the substrate S is sealed by the sample sheet X' under the sealing conditions of a temperature of 70°C, a vacuum degree of less than 1.6 kPa, a pressure of 0.1 MPa and a pressure time of 40 seconds using a vacuum plate (pressurization step).

[0161] Then, as shown in Figure 4D, the sample sheet X' is hardened by heating at 150°C for 1 hour under atmospheric pressure.

[0162] Next, as shown in the enlarged view of FIG4D, taking the side surface 21b of the dummy wafer 21' as a reference, the length of the sealing resin (a portion of the first sealing resin layer 11) from the sample sheet X' entering the gap G between the dummy wafer 21' and the substrate S from the side surface 21b is measured and taken as the entry length L (μm). The results are shown in Tables 2 to 4. The negative entry length L represents the space formed protruding outward from the side surface 21b of the dummy wafer 21' (refer to the thick dashed line in FIG4D). The absolute value of the negative value corresponds to the protrusion length of the space.

[0163] According to the sealing resin sheets of Examples 1 to 9, the insertion length L is 0 μm or more and 50 μm or less, so that the dummy wafer 21' can be properly hollowed and sealed.

[0164] In contrast, regarding the sealing resin sheet of Comparative Example 1, it was unable to adequately fill the spaces between the dummy wafers 21' during the pressurization step (FIG. 4C). Specifically, a gap (vacancy) was formed between the substrate S and the sealing resin sheet X' in the area between the dummy wafers 21'. Regarding the sealing resin sheet of Comparative Example 2, a fracture occurred in the first sealing resin layer 11 during the pressurization step. Therefore, a portion of the second sealing resin layer 12 flowed into the dummy wafer 21' side through the fractured portion of the first sealing resin layer 11. This flowing resin flowed between the dummy wafer 21' and the first sealing resin layer 11 and reached the gap G, and excessively entered the gap G. Regarding the sealing resin sheets of Comparative Examples 3 and 5, during the pressurization step, the first sealing resin layer 11 excessively entered the gap G between the substrate S and the dummy wafer 21'. In Comparative Example 4, the sealing resin sheet had insufficient fluidity during the pressurization step, resulting in an inability to properly seal the gap G (the penetration length L was negative).

[0165] [Table 2] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 First sealing resin layer Production example 1 Production example 1 Production example 1 Production example 2 Production example 2 Production example 2 Production example 2 Production example 2 Thickness H1 (μm) 100 150 200 100 150 200 80 150 Inorganic filler content ratio R1 (mass %) 83 83 83 85 85 85 85 85 Content ratio (mass%) of layered silicate compounds 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Minimum melt viscosity (kPa·s) 160 160 160 240 240 240 240 240 Average linear thermal expansion coefficient Z1 (ppm / ℃) 17 17 17 13 13 13 13 13 Second sealing resin layer Production example 5 Production example 5 Production example 5 Production example 5 Production example 5 Production example 5 Production example 5 Production example 8 Thickness H2 (μm) 150 100 50 150 100 50 120 100 Inorganic filler content ratio R2 (mass %) 84 84 84 84 84 84 84 91 Average linear thermal expansion coefficient Z2 (ppm / ℃) 10 10 10 10 10 10 10 10 H1 / Total Thickness 0.40 0.60 0.80 0.40 0.60 0.80 0.40 0.60 Entering length L (μm) 48 33 17 42 29 13 5 15

[0166] [Table 3] Example 9 First sealing resin layer Production example 2 Thickness H1 (μm) 100 Inorganic filler content ratio R1 (mass %) 85 Content ratio (mass%) of layered silicate compounds 2.0 Minimum melt viscosity (kPa·s) 240 Average linear thermal expansion coefficient Z1 (ppm / ℃) 13 Third sealing resin layer Production example 1 Thickness H3 (μm) 50 Inorganic filler content ratio R3 (mass %) 83 Content ratio (mass%) of layered silicate compounds 2.0 Average linear thermal expansion coefficient Z3 (ppm / ℃) 17 Second sealing resin layer Production example 5 Thickness H2 (μm) 100 Inorganic filler content ratio R2 (mass %) 84 Average linear thermal expansion coefficient Z2 (ppm / ℃) 10 H1 / Total Thickness 0.40 (H1 + H3) / Total Thickness 0.60 Entering length L (μm) 32

[0167] [Table 4] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 First sealing resin layer Production example 1 Production example 2 Production example 3 Production example 4 Production example 3 Thickness H1 (μm) 100 80 100 100 100 Inorganic filler content ratio R1 (mass %) 83 85 81 86 81 Content ratio (mass%) of layered silicate compounds 2.0 2.0 2.0 2.5 2.0 Minimum melt viscosity (kPa·s) 160 240 100 360 100 Average linear thermal expansion coefficient Z1 (ppm / ℃) 17 13 twenty two 14 twenty two Second sealing resin layer Production example 5 Production example 5 Production example 6 Production example 6 Production example 7 Thickness H2 (μm) 20 200 150 150 150 Inorganic filler content ratio R2 (mass %) 84 84 70 70 81 Average linear thermal expansion coefficient Z2 (ppm / ℃) 10 10 42 42 17 H1 / Total Thickness 0.83 0.29 0.40 0.40 0.40 Entering length L (μm) - 100 80 -100 85 [Simplified Explanation of the Diagram]

[0032] FIG1 is a cross-sectional schematic diagram of one embodiment of the sealing resin sheet of the present invention. FIG2A-2C show a method for sealing an electronic component chip on a substrate using the sealing resin sheet shown in FIG1. ​​FIG2A shows the step of placing the workpiece and the sealing resin sheet between the pressure plates in a flatbed press, FIG2B shows the pressurization step, and FIG2C shows the curing step. FIG3 is a cross-sectional schematic diagram of a variation of the sealing resin sheet shown in FIG1. ​​In this variation, the sealing resin sheet has a three-layer structure. Regarding FIG4A-4D, FIG4A shows the step of preparing the sealing resin sheet, FIG4B shows the step of placing the workpiece and the sealing resin sheet between the pressure plates in a flatbed press, FIG4C shows the pressurization step, and FIG4D shows the curing step.

Claims

1. A sealing resin sheet comprising a first sealing resin layer and a second sealing resin layer sequentially in the thickness direction, wherein the first sealing resin layer contains a first thermosetting resin and a first inorganic filler, and has an average linear thermal expansion coefficient of less than 20 ppm / ℃ in a temperature range of -40°C to glass transition temperature after curing; the second sealing resin layer contains a second thermosetting resin and a second inorganic filler, and has an average linear thermal expansion coefficient of less than 20 ppm / ℃ in a temperature range of -40°C to glass transition temperature after curing; the content ratio of the first inorganic filler in the first sealing resin layer is different from the content ratio of the second inorganic filler in the second sealing resin layer; and the thickness of the first sealing resin layer is 0.37 to 0.82 of the total thickness of the sealing resin sheet.

2. The sealing resin sheet as claimed in claim 1, wherein the first sealing resin layer has a thickness of 90 μm or more.

3. The sealing resin sheet as claimed in claim 1, wherein the first sealing resin layer has a minimum melt viscosity of 120 kPa·s or higher.

4. The sealing resin sheet as claimed in claim 1, wherein the first sealing resin layer has a minimum melt viscosity of 260 kPa·s or less.

5. The sealing resin sheet of claim 1, wherein a third sealing resin layer is provided between the first sealing resin layer and the second sealing resin layer, the third sealing resin layer containing a third thermosetting resin and a third inorganic filler, and having an average linear thermal expansion coefficient of less than 20 ppm / ℃ in a temperature range of -40℃ to glass transition temperature after curing.

6. The sealing resin sheet of claim 5, wherein the third sealing resin layer is in direct contact with the first sealing resin layer, and the ratio of the total thickness of the first sealing resin layer and the thickness of the third sealing resin layer to the total thickness of the sealing resin sheet is 0.4 or more and 0.82 or less.

7. For any of the sealing resin sheets in claims 1 to 6, the inorganic filler content in each sealing resin layer is 75% by mass or more.

8. For any of the sealing resin sheets in claims 1 to 6, the inorganic filler content in each sealing resin layer is 90% by mass or less.

9. An electronic component device comprising: a substrate; an electronic component chip mounted on the substrate in a state facing the substrate with a gap between them; and a hardened resin portion formed of a sealing resin sheet as claimed in any one of claims 1 to 8, for sealing the electronic component chip and the gap.

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