JP2021197496A - Sealing-resin sheet - Google Patents

Abstract

To provide a sealing-resin sheet suitable for machining the surface of a sealing resin for sealing an electronic component chip with good precision in a manufacturing process of a resin seal body of the electronic component chip mounted on a substrate.SOLUTION: A sealing-resin sheet X according to the present invention comprises a thermosetting resin. The sealing-resin sheet is 80% or larger in warp-recovery R given by the formula (1) below in a warp-recovery evaluation test arranged to perform a predetermined first treatment, a first measurement, a second treatment and a second measurement in this order. Formula (1): R=[(D1-D2)/D1]×100.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sealing resin sheet.

Conventionally, an electronic component chip such as a semiconductor chip mounted on a mounting substrate is sealed on the substrate by a sheet-shaped encapsulating resin material (encapsulating resin sheet) containing a thermosetting resin to form an electronic component chip. Resin encapsulation may be manufactured. In the sealing process, for example, a sealing resin sheet having a predetermined thickness is pressed against a plurality of electronic component chips bonded on the same surface of a substrate and separated from each other in a heat-softened state by a flat plate press. , The sheet is plastically deformed to cover each electronic component chip (pressing process). Then, the sealing resin sheet covering the electronic component chip is cured by heating at a high temperature (curing step). After that, for example, by blade dicing, the cured encapsulating resin sheet is cut along a predetermined cutting schedule line, and individualized into each resin encapsulating body. A technique relating to resin encapsulation of an electronic component chip by an encapsulation resin sheet is described in, for example, Patent Document 1 below.

Japanese Unexamined Patent Publication No. 2015-220350

Internal stress is generated in the sealing resin sheet (sealing resin material) that has been heat-cured in the curing step. This internal stress may cause warpage in the work obtained through the curing step (for example, a plurality of electronic component chips on a substrate are sealed by a sealing resin sheet). The larger the work size, that is, the larger the size of the sealing resin sheet used, the larger the height difference generated on the surface of the work due to the warping of the work. If the height difference on the work surface is too large, surface processing such as laser printing performed on the surface of the encapsulating resin for each electronic component chip in the work cannot be performed accurately over the entire work.

INDUSTRIAL APPLICABILITY The present invention is a sealing resin suitable for accurately processing the surface of a sealing resin for encapsulating an electronic component chip in the process of manufacturing a resin encapsulating body for an electronic component chip mounted on a base material. Provide a sheet.

The present invention [1] is a sealing resin sheet containing a thermosetting resin, and the following first treatment, first measurement, second treatment, and second measurement are carried out in this order. In the warp recovery evaluation test, a sealing resin sheet having a warp recovery rate R represented by the following formula (1) of 80% or more is included.

First treatment: A laminate sample comprising a 42-alloy plate having a size of 90 mm × 90 mm × 150 μm and the sealing resin sheet bonded to the entire one surface of the 42 alloy plate in the thickness direction is prepared as 150. After heating at ° C. for 1 hour, let stand at 25 ° C. for 1 hour.
First measurement: The maximum value of the distance between the mounting surface on which the laminated body sample is placed and the edge of the laminated body sample with the 42 alloy plate of the laminated body sample facing down is set. 1 Measure as the warp length D1.
Second treatment: The laminated body sample is allowed to stand on the surface of a hot plate at 100 ° C. for 1 minute.
Second measurement: The maximum value of the distance between the surface of the heating plate and the edge of the laminated body sample is measured as the second warp length D2.

Equation (1): R = [(D1-D2) / D1] × 100

The configuration in which the warp recovery rate R shown in the warp recovery evaluation test is 80% or more suppresses the height difference of the work surface in the manufacturing process of the electronic component chip resin encapsulation body in which the main encapsulation resin sheet is used. , Suitable for processing the sealing resin surface with high accuracy.

The present invention [2] includes the sealing resin sheet according to the above [1], wherein the second warp length D2 is 2 mm or less.

Such a configuration is suitable for accurately processing the surface of the encapsulating resin in the manufacturing process of the electronic component chip resin encapsulation body in which the present encapsulation resin sheet is used.

In the present invention [3], the sealing resin sheet includes a first sealing resin layer and a second sealing resin layer in order in the thickness direction, and the first sealing resin layer has a first heat. The sealing resin according to the above [1] or [2], which contains a curable resin and a layered silicate compound, and the second sealing resin layer contains a second thermosetting resin. Includes sheet.

The main encapsulation resin sheet provided with such first and second encapsulation resin layers is, for example, an electronic component chip mounted on the substrate in a state of facing the substrate via a gap. It can be used for sealing through the following pressing and curing steps. In the pressing process, the sheet is pressed toward the base material while being heated and softened in a state where the first sealing resin layer side of the main sealing resin sheet is in contact with the electronic component chip on the base material (electronic component chip). The open edge of the void is closed by the first sealing resin layer that is in close contact with the substrate around it). In such a pressing process, in the present encapsulation resin sheet, the first encapsulation resin layer and the second encapsulation resin layer are softened and flowed under the pressing force to be deformed according to the outer shape of the electronic component chip. (The structure in which the first encapsulating resin layer contains the layered silicate compound, while thickening the first encapsulating resin layer, receives the pressing force in the first encapsulating resin layer. It is suitable for developing a thixotropic property that makes the viscosity lower than when it is not present). In the curing step after the pressing step, the main sealing resin sheet covering the electronic component chip is further heated and cured. Since the first sealing resin layer contains the layered silicate compound, the decrease in viscosity due to the temperature rise is suppressed in the curing step, and the excessive entry into the voids is suppressed (in contrast to this). , The viscosity of the second sealing resin layer is once lowered and fluidized before curing, and the exposed surface on the opposite side of the first sealing resin layer is flattened). That is, the present encapsulation resin sheet is suitable for controlling the length of the encapsulating resin entering into the gap between the substrate and the electronic component chip in the manufacturing process of the electronic component chip resin encapsulation body.

In the present invention [4], the seal according to the above [3], wherein the following entry length L shown in the entry length evaluation test in which the following steps 1 to 4 are carried out is 0 μm or more and 50 μm or less. Includes a resin sheet for stopping.

First step: A glass substrate and a dummy chip having a size of 3 mm × 3 mm × thickness of 200 μm are provided, and the dummy chip is opposed to the glass substrate through a gap through a bump on the glass substrate. A dummy chip mounting substrate having a length from the glass substrate to the dummy chip in the gap of 20 μm is prepared.
Second step: With the dummy chip on the glass substrate in contact with the first sealing resin layer side of the sealing resin sheet, the sealing resin sheet is evacuated at a temperature of 65 ° C. by a vacuum plate press. The first sealing resin layer, which is pressed toward the glass substrate under the conditions of a degree of 1.6 kPa or less, a pressing force of 0.1 MPa, and a pressurizing time of 40 seconds, is in close contact with the glass substrate around the dummy chip. Close the open edge of the void.
Third step: After the second step, the sealing resin sheet is cured by heating at 150 ° C. for 1 hour under atmospheric pressure.
Fourth step: After the third step, the entry length L of the sealing resin sheet into the void is measured.

The configuration in which the penetration length L shown in the penetration length evaluation test is 0 μm or more and 50 μm or less is an electronic component chip resin encapsulation body including the above-mentioned pressing step and curing step in which the present encapsulation resin sheet is used. It is suitable for controlling the length of the sealing resin entering into the gap between the substrate and the electronic component chip in the manufacturing process.

In the present invention [5], the first sealing resin layer has a first tensile storage elastic modulus of 3.5 GPa or more at 25 ° C. after heat treatment at 150 ° C. for 1 hour, as described above [3] or [4]. ] Is included in the sealing resin sheet described in.

In such a configuration, in the manufacturing process of the electronic component chip resin encapsulation body in which the resin sheet for encapsulation is used, cracks, chipping, etc. are formed on the base material on which the electronic component chip is mounted at the time of individualization by blade dicing. Suitable for suppressing the occurrence of damage.

In the present invention [6], the second sealing resin layer has a glass transition temperature of 100 ° C. or lower after being heat-treated at 150 ° C. for 1 hour, according to any one of the above [3] to [5]. Includes the encapsulation resin sheet described.

With such a configuration, when the main sealing resin sheet after heat curing is warped, the sealing resin sheet is once softened by heating at about 100 ° C. to reduce the warp of the sheet. Suitable for.

In the present invention [7], the second sealing resin layer has a second tensile storage elastic modulus of 0.5 GPa or less at 100 ° C. after heat treatment at 150 ° C. for 1 hour, from the above [3] to [6]. ] Is included in the sealing resin sheet according to any one of the above.

With such a configuration, when the main sealing resin sheet after heat curing is warped, the sealing resin sheet is once softened by heating at about 100 ° C. to reduce the warp of the sheet. Suitable for.

INDUSTRIAL APPLICABILITY [8] The present invention [8] is the second after heat treatment at 150 ° C. for 1 hour with respect to the first tensile storage elastic modulus of the first sealing resin layer after heat treatment at 150 ° C. for 1 hour. The sealing resin sheet according to any one of the above [1] to [4], wherein the ratio of the second tensile storage elastic modulus of the sealing resin layer at 100 ° C. is 0.12 or less.

Such a configuration is suitable for both the above-mentioned suppression of warpage and the above-mentioned suppression of damage.

It is sectional drawing of one Embodiment of the resin sheet for sealing of this invention. A method of sealing an electronic component chip on a base material using the sealing resin sheet shown in FIG. 1 is shown. FIG. 2A represents a process of preparing a sealing resin sheet, FIG. 2B represents a process of arranging a work and a sealing resin sheet between the press plates in a flat plate press, and FIG. 2C represents a pressing process. FIG. 2D represents a curing process. Represents an approach length evaluation test in Examples and Comparative Examples. FIG. 3A represents a process of preparing a sealing resin sheet, FIG. 3B represents a process of arranging a work and a sealing resin sheet between the press plates in a flat plate press, and FIG. 3C represents a pressing process. FIG. 3D represents a curing process.

The sealing resin sheet X is a sheet-shaped sealing resin material for sealing electronic component chips such as semiconductor chips, and has a thickness of a first sealing resin layer 11 and a second sealing resin layer 12. Prepare in order in the direction. The sealing resin sheet X preferably consists of only the first sealing resin layer 11 and the second sealing resin layer 12 located on one surface of the first sealing resin layer 11 in the thickness direction.

The first sealing resin layer 11 is a layer formed from a thermosetting composition (first thermosetting composition), and in the present embodiment, at least a thermosetting resin and a layered silicate compound are provided. It may be contained and may contain an inorganic filler (first inorganic filler). The first sealing resin layer 11 is in an uncured state (A stage state) or a semi-cured state (B stage state).

Examples of the thermosetting resin include epoxy resin, silicone resin, urethane resin, polyimide resin, urea resin, melamine resin, and unsaturated polyester resin. These thermosetting resins may be used alone or in combination of two or more. The content ratio of the thermosetting resin in the first thermosetting composition is preferably 10% by mass or more, more preferably 15% by mass or more. The content ratio of the thermosetting resin in the first thermosetting composition is preferably 50% by mass or less, more preferably 40% by mass or less.

As the thermosetting resin, an epoxy resin is preferably used. The epoxy resin is prepared, for example, as an epoxy resin composition containing a main agent, a curing agent and a curing accelerator.

Examples of the main agent include bifunctional epoxy resins such as 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, and phenol novolac type epoxy resin. , Cresol novolak type epoxy resin, trishydroxyphenylmethane type epoxy resin, tetraphenylol ethane type epoxy resin, dicyclopentadiene type epoxy resin and other trifunctional or higher functional epoxy resins can be mentioned. These main agents may be used alone or in combination of two or more. As the main agent, a bifunctional epoxy resin is preferably used, and more preferably at least one selected from the group consisting of a bisphenol A type epoxy resin and a bisphenol F type epoxy resin is used.

The epoxy equivalent of the main agent is, for example, 10 g / eq. Or more, preferably 100 g / eq. Or more. The epoxy equivalent of the main agent is, for example, 500 g / eq. Or less, preferably 450 g / eq. Or less.

The softening point of the main agent is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, still more preferably 72 ° C. or higher, and particularly preferably 75 ° C. or higher. The softening point of the main agent is preferably 130 ° C. or lower, more preferably 110 ° C. or lower, still more preferably 90 ° C. or lower. According to such a configuration, it is easy to mix the composition at the time of preparing the first thermosetting composition, and it is easy to control the flow characteristics of the composition after mixing.

The proportion of the main agent in the first thermosetting composition is, for example, 3% by mass or more, preferably 5% by mass or more. The proportion of the main agent in the first thermosetting composition is, for example, 17% by mass or less, preferably 15% by mass or less.

As the curing agent, a phenol resin is preferably used. Examples of the phenol resin include novolak-type phenol resins such as phenol novolac resin, phenol aralkyl resin, cresol novolak resin, tert-butylphenol novolak resin, and nonylphenol novolak resin. As the curing agent, at least one selected from the group consisting of a phenol novolac resin and a phenol aralkyl resin is preferably used.

In the epoxy resin composition, the amount of hydroxyl groups in the phenolic resin as a curing agent is, for example, 0.7 equivalents or more, preferably 0.9 equivalents or more, with respect to 1 equivalent of epoxy groups in the epoxy resin as the main agent. The amount of hydroxyl groups in the phenolic resin as a curing agent is, for example, 1.5 equivalents or less, preferably 1.2 equivalents or less, with respect to 1 equivalent of epoxy groups in the epoxy resin as the main agent.

The curing accelerator is a catalyst (thermosetting catalyst) that accelerates the curing of the main agent by heating. Examples of the curing accelerator include imidazole compounds and organophosphorus compounds. Examples of the imidazole compound include 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Examples of the organophosphorus compound include triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine. As the curing accelerator, an imidazole compound is preferably used, and 2-phenyl-4,5-dihydroxymethylimidazole is more preferably used. The blending amount of the curing accelerator with respect to 100 parts by mass of the main agent is, for example, 0.05 parts by mass or more. The blending amount of the curing accelerator with respect to 100 parts by mass of the main agent is, for example, 5 parts by mass or less.

The layered silicate compound is a component that thickens the first thermosetting composition while exhibiting thixotropic properties in the first thermosetting composition, and is dispersed in the first thermosetting composition. ..

Layered silicate compounds include, for example, smectite, kaolinite, halloysite, talc, and mica. Smectite includes, for example, montmorillonite, byderite, nontronite, saponite, hectorite, saponite, and stephensite. As the layered silicate compound, smectite is preferably used, and more preferably montmorillonite, because it is easy to mix with a thermosetting resin.

The layered silicate compound may be an unmodified product having an unmodified surface, or a modified product having a surface modified by an organic component. For example, from the viewpoint of compatibility with a thermosetting resin, a layered silicate compound whose surface is modified with an organic component is preferably used, and more preferably an organic smectite whose surface is modified with an organic component is used. It is used, and more preferably, an organic bentonite whose surface is modified with an organic component is used.

Examples of the organic component include organic cations (onium ions) such as ammonium, imidazolium, pyridinium, and phosphonium.

Ammoniums include, for example, dimethyl distearyl ammonium, disstearyl ammonium, octadecyl ammonium, hexyl ammonium, octyl ammonium, 2-hexyl ammonium, dodecyl ammonium, and trioctyl ammonium. Examples of the imidazolium include methylstearyl imidazolium, distearyl imidazolium, methylhexyluimidazole, dihexyluimidazole, methyloctylimidazolium, dioctylimidazolium, methyldodecylimidazolium, and zidodecylimidazolium. Examples of pyridiniums include stearylpyridinium, hexylpyridinium, octylpyridinium, and dodecylpyridinium. Phosphoniums include, for example, dimethyl distearyl phosphonium, disstearyl phosphonium, octadecylphosphonium, hexylphosphonium, octylphosphonium, 2-hexylphosphonium, dodecylphosphonium, and birds. Octylphosphonium can be mentioned. The organic cations may be used alone or in combination of two or more. As the organic cation, ammonium is preferably used, and more preferably dimethyl distearyl ammonium is used.

As the organic layered silicate compound, preferably, an organic smectite having a surface modified with ammonium is used, and more preferably, an organic bentonite having a surface modified with dimethyl distearyl ammonium is used.

The average particle size of the layered silicate compound is, for example, 1 nm or more, preferably 5 nm or more, and more preferably 10 nm or more. The average particle size of the layered silicate compound is, for example, 100 μm or less, preferably 50 μm or less, and more preferably 10 μm or less. The average particle size of the layered silicate compound is determined as a D50 value (cumulative 50% median diameter) based on, for example, the particle size distribution determined by the particle size distribution measurement method in the laser scattering method.

As the layered silicate compound, a commercially available product can be used. Examples of commercially available organic bentonite products include the Esben series (manufactured by Hojun).

The content ratio of the layered silicate compound in the first sealing resin layer 11 (that is, the content ratio of the layered silicate compound in the first thermosetting resin composition) is preferably 1.2% by mass or more. More preferably, it is 1.5% by mass or more. The content ratio of the layered silicate compound in the first sealing resin layer 11 is preferably 5.5% by mass or less, and more preferably 5% by mass or less. The configuration in which the first sealing resin layer 11 contains 1.2% by mass or more and 5.5% by mass or less of the layered silicate compound causes the first sealing resin layer 11 to be thickened while the first sealing resin layer 11 is thickened. In the resin layer 11, it is suitable for exhibiting a thixotropic property that makes the viscosity lower when a pressing force is applied than when the pressing force is applied.

The first inorganic filler is an inorganic filler other than the layered silicate compound, for example, a silicon compound such as silica or silicon nitride (a silicon compound other than the layered silicate compound), orthosilicate, orthosilicate. Examples thereof include silicate compounds other than layered silicate compounds such as salts and innosilicates. Examples of the first inorganic filler include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whisker, and boron nitride. The first inorganic filler may be used alone or in combination of two or more. As the first inorganic filler, a silicon compound other than the layered silicate compound is preferably used, and silica is more preferably used.

Examples of the shape of the first inorganic filler include a substantially spherical shape, a substantially plate shape, a substantially needle shape, and an indefinite shape, and a substantially spherical shape is preferable.

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

The surface of the first inorganic filler may be partially or wholly surface-treated with a surface treatment agent such as a silane coupling agent.

The content ratio of the first inorganic filler in the first sealing resin layer 11 (that is, the content ratio of the first inorganic filler in the first thermosetting composition) is preferably 50% by mass or more, more preferably 60% by mass. % Or more. Such a configuration is suitable for suppressing the degree of expansion and contraction due to a temperature change in the first sealing resin layer 11. The content ratio of the first inorganic filler in the first sealing resin layer 11 is preferably 90% by mass or less, more preferably 80% by mass or less. Such a configuration is suitable for ensuring the fluidity of the first sealing resin layer 11 in the pressing process described later.

The first thermosetting composition may contain other components. Other components include, for example, thermoplastics, pigments, and silane coupling agents.

Examples of the thermoplastic resin include acrylic resin, natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, and the like. Polycarbonate resin, thermoplastic polyimide resin, polyamide resin (6-nylon, 6,6-nylon, etc.), phenoxy resin, saturated polyester resin (PET, etc.), polyamideimide resin, fluororesin, and styrene-isobutylene-styrene block co-weight Coalescence is mentioned. These thermoplastic resins may be used alone or in combination of two or more.

As the thermoplastic resin, an acrylic resin is preferably used from the viewpoint of ensuring compatibility between the thermosetting resin and the thermoplastic resin.

Examples of the acrylic resin include a (meth) acrylic polymer which is a polymer of a monomer component containing a (meth) acrylic acid alkyl ester having a linear or branched alkyl group and another monomer (copolymerizable monomer). Can be mentioned.

Examples of the alkyl group of the (meth) acrylic acid alkyl ester include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, isobutyl, pentyl and hexyl.

Examples of the copolymerizable monomer include a carboxyl group-containing monomer, an acid anhydride monomer, a glycidyl group-containing monomer, a hydroxyl group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, and an acrylonitrile. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the acid anhydride monomer include maleic anhydride and itaconic anhydride. Examples of the glycidyl group-containing monomer include glycidyl acrylate and glycidyl methacrylate. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and (meth). ) 8-Hydroxyoctyl acrylate, 10-hydroxydecyl (meth) acrylate, and 12-hydroxylauryl (meth) acrylate. Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth). ) Acryloyloxynaphthalene sulfonic acid can be mentioned. Examples of the phosphoric acid group-containing monomer include 2-hydroxyethylacryloyl phosphate. These copolymerizable monomers may be used alone or in combination of two or more.

The glass transition temperature (Tg) of the thermoplastic resin is, for example, −70 ° C. or higher. The glass transition temperature is, for example, 0 ° C. or lower, preferably −5 ° C. or lower. The glass transition temperature is, for example, a theoretical value obtained by the Fox formula, and a specific calculation method thereof is described in, for example, Japanese Patent Application Laid-Open No. 2016-175976.

The weight average molecular weight of the thermoplastic resin is, for example, 100,000 or more, preferably 300,000 or more. The weight average molecular weight of the thermoplastic resin is, for example, 2 million or less, preferably 1 million or less. The weight average molecular weight of the resin is measured by gel permeation chromatography (GPC) based on standard polystyrene conversion values.

The content ratio of the thermoplastic resin in the first thermosetting composition is, for example, 1% by mass or more, preferably 2% by mass or more. The content ratio of the thermoplastic resin in the thermosetting composition is, for example, 80% by mass or less, preferably 60% by mass or less.

Examples of the pigment include a black pigment such as carbon black. The particle size of the pigment is, for example, 0.001 μm or more. The particle size of the pigment is, for example, 1 μm or less. The particle size of the pigment is an arithmetic mean diameter obtained by observing the pigment with an electron microscope. Further, the content ratio of the pigment in the thermosetting composition is, for example, 0.1% by mass or more. The content ratio is, for example, 2% by mass or less.

Examples of the silane coupling agent include a silane coupling agent containing an epoxy group. Examples of the epoxy group-containing silane coupling agent include 3-glycidoxydialkyldialkoxysilanes such as 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane, and 3-glyci. Examples thereof include 3-glycidoxyalkyltrialkoxysilanes such as sidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. As the silane coupling agent, 3-glycidoxyalkyltrialkoxysilane is preferably used, and 3-glycidoxypropyltrimethoxysilane is more preferably used. The content ratio of the silane coupling agent in the first thermosetting composition is, for example, 0.1% by mass or more, preferably 1% by mass or more. The content ratio of the silane coupling agent in the thermosetting composition is, for example, 10% by mass or less, preferably 5% by mass or less.

The glass transition temperature of the first sealing resin layer 11 after heat treatment at 150 ° C. for 1 hour is preferably 135 ° C. or lower, more preferably 130 ° C. or lower, still more preferably 125 ° C. or lower. The glass transition temperature is, for example, 60 ° C. or higher. The glass transition temperature of the first sealing resin layer 11 can be obtained based on the maximum value of the loss tangent (tan δ) in the dynamic viscoelasticity measurement described later with respect to the examples (described later in the second sealing resin layer 12). The same applies to the glass transition temperature).

The tensile storage elastic modulus (first tensile storage elastic modulus) at 25 ° C. that the first sealing resin layer 11 has after heat treatment at 150 ° C. for 1 hour is preferably 3.5 GPa or more, more preferably 3.8 GPa. Above, more preferably 4 GPa or more. The first tensile storage elastic modulus is preferably 9 GPa or less, more preferably 8 GPa or less, and further preferably 7.7 GPa or less. The value of the tensile storage elastic modulus is a value obtained by the dynamic viscoelasticity measurement described later with respect to the examples (the same applies to the value of the tensile storage elastic modulus described later).

The tensile storage elastic modulus at 100 ° C. that the first sealing resin layer 11 has after heat treatment at 150 ° C. for 1 hour is preferably 0.35 GPa or more, more preferably 0.38 GPa or more, still more preferably 0.4 GPa. That is all. The tensile storage elastic modulus is preferably 3 GPa or less, more preferably 2.8 GPa or less, and further preferably 2.5 GPa or less.

The elastic modulus of the first sealing resin layer 11 after heat treatment at 150 ° C. for 1 hour at 25 ° C. measured by the nanoindentation method is preferably 3.5 GPa or more, more preferably 3.8 GPa or more, and further. It is preferably 4 GPa or more. The elastic modulus is preferably 9 GPa or less, more preferably 8 GPa or less, still more preferably 7.7 GPa or less.

For the measurement of the elastic modulus by the nanoindentation method, for example, a nanoindenter (trade name “Triboinder”, manufactured by Hysiron) can be used (the same applies to each elastic modulus measured by the nanoindentation method described later). ). In this measurement, the measurement mode is single indentation measurement, the measurement temperature is 25 ° C., the indenter used is a Berkovich (triangular pyramid) type diamond indenter, and the indentation depth of the indenter with respect to the object to be measured is 300 nm. The pushing speed is 10 nm / sec, and the withdrawal speed of the indenter from the object to be measured is 10 nm / sec. The elastic modulus based on the nanoindentation method is derived by the device used. The specific derivation method is as described in, for example, the Handbook of Micro / nano Tribology (Second Edition) Edited by Bharat Bhushan, CRC Press (ISBN 0-8493-8402-8).

The elastic modulus of the first sealing resin layer 11 after heat treatment at 150 ° C. for 1 hour at 100 ° C. measured by the nanoindentation method is preferably 0.35 GPa or more, more preferably 0.38 GPa or more, and further. It is preferably 0.4 GPa or more. The tensile storage elastic modulus is preferably 3 GPa or less, more preferably 2.8 GPa or less, and further preferably 2.5 GPa or less.

The second sealing resin layer 12 is a layer formed from a thermosetting composition (second thermosetting composition), and in the present embodiment, contains at least a thermosetting resin and is a second inorganic filler. May be contained. The second sealing resin layer 12 is in an uncured state (A stage state) or a semi-cured state (B stage state).

Examples of the thermosetting resin include the thermosetting resins described above for the first thermosetting composition. The content ratio of the thermosetting resin in the second thermosetting composition is preferably 13% by mass or more, more preferably 15% by mass or more. The content ratio of the thermosetting resin in the second thermosetting composition is preferably 35% by mass or less, more preferably 30% by mass or less.

As the thermosetting resin in the second thermosetting composition, an epoxy resin is preferably used. The epoxy resin is prepared, for example, as an epoxy resin composition containing a main agent, a curing agent and a curing accelerator.

As the main agent, for example, the above-mentioned main agent for the first thermosetting composition can be mentioned, preferably a bifunctional epoxy resin is used, and more preferably a bisphenol F type epoxy resin is used. With respect to the second thermosetting composition, the range of the epoxy equivalent of the main agent, the range of the softening point of the main agent, and the range of the ratio of the main agent in the epoxy resin composition are the ranges of the above-mentioned main agent with respect to the first thermosetting composition. It is the same as the range of the epoxy equivalent, the range of the softening point of the main agent, and the range of the ratio of the main agent in the epoxy resin composition.

As the curing agent, a phenol resin is preferably used, and more preferably a phenol novolac resin is used, as described above for the first thermosetting composition.

With respect to the second thermosetting composition, the range of the amount of hydroxyl groups in the phenolic resin as a curing agent with respect to one equivalent of the epoxy group in the epoxy resin as the main agent is the range of the amount of hydroxyl groups in the phenolic resin described above with respect to the first thermosetting composition. It is the same as the range of the amount of hydroxyl groups (1 equivalent to epoxy group).

Examples of the curing accelerator include the main agent described above for the first thermosetting composition, preferably an imidazole compound, and more preferably 2-phenyl-4,5-dihydroxymethylimidazole. The blending amount of the curing accelerator with respect to 100 parts by mass of the main agent is, for example, 0.05 parts by mass or more, and the blending amount is, for example, 5 parts by mass or less.

Examples of the second inorganic filler include the first inorganic filler described above for the first thermosetting composition, preferably a silicon compound other than the layered silicate compound, and more preferably silica. Used.

Examples of the shape of the second inorganic filler include a substantially spherical shape, a substantially plate shape, a substantially needle shape, and an indefinite shape, and a substantially spherical shape is preferable. The range of the average value of the maximum length of the second inorganic filler (the average particle size in the case of the substantially spherical second inorganic filler) is as described above as the average value of the maximum length of the first inorganic filler. The same is true. The surface of the second inorganic filler may be partially or wholly surface-treated with a surface treatment agent such as a silane coupling agent.

The content ratio of the second inorganic filler in the second sealing resin layer 12 (that is, the content ratio of the second inorganic filler in the second thermosetting composition) is preferably 60% by mass or more, more preferably. It is 65% by mass or more, more preferably 70% by mass or more. Such a configuration is suitable for suppressing the degree of expansion and contraction due to a temperature change in the second sealing resin layer 11. The content ratio of the second inorganic filler in the second sealing resin layer 12 is preferably 90% by mass or less, more preferably 87% by mass or less, still more preferably 85% by mass or less. Such a configuration is suitable for ensuring the fluidity of the second sealing resin layer 12 in the pressing process described later.

The second thermosetting composition may contain other components. Other components include, for example, thermoplastic resins, pigments, and silane coupling agents similar to those described above for the first thermosetting composition.

The glass transition temperature of the second sealing resin layer 12 after heat treatment at 150 ° C. for 1 hour is preferably 100 ° C. or lower, more preferably 95 ° C. or lower, still more preferably 90 ° C. or lower. The glass transition temperature is, for example, 60 ° C. or higher.

The tensile storage elastic modulus (second tensile storage elastic modulus) at 100 ° C. that the second sealing resin layer 12 has after heat treatment at 150 ° C. for 1 hour is preferably 0.5 GPa or less, more preferably 0.4 GPa or less. Below, it is more preferably 0.38 GPa or less. The second tensile storage elastic modulus is preferably 0.03 GPa or more, more preferably 0.05 GPa or more, and further preferably 0.07 GPa or more.

The tensile storage elastic modulus at 25 ° C. that the second sealing resin layer 12 has after heat treatment at 150 ° C. for 1 hour is preferably 3 GPa or more, more preferably 4 GPa or more, still more preferably 5 GPa or more. The tensile storage elastic modulus is preferably 11 GPa or less, more preferably 10 GPa or less, still more preferably 9 GPa or less.

The second tensile storage elastic modulus (after the heat treatment at 150 ° C. for 1 hour) with respect to the first tensile storage elastic modulus (the tensile storage elastic modulus at 25 ° C. of the first sealing resin layer after the heat treatment at 150 ° C. for 1 hour). The ratio of the tensile storage elastic modulus of the second sealing resin layer at 100 ° C.) is preferably 0.12 or less, more preferably 0.1 or less, still more preferably 0.08 or less. The ratio is preferably 0.005 or more, more preferably 0.01 or more.

The elastic modulus of the second sealing resin layer 12 after heat treatment at 150 ° C. for 1 hour at 100 ° C. measured by the nanoindentation method is preferably 0.5 GPa or less, more preferably 0.4 GPa or less, and further. It is preferably 0.38 GPa or less. The elastic modulus is preferably 0.03 GPa or more, more preferably 0.05 GPa or more, and further preferably 0.07 GPa or more.

The elastic modulus of the second sealing resin layer 12 after heat treatment at 150 ° C. for 1 hour at 25 ° C. measured by the nanoindentation method is preferably 3 GPa or more, more preferably 4 GPa or more, still more preferably 5 GPa or more. Is. The elastic modulus is preferably 11 GPa or less, more preferably 10 GPa or less, still more preferably 9 GPa or less.

For the sealing resin sheet X, for example, the first sealing resin layer 11 and the second sealing resin layer 12 are formed, and then the first sealing resin layer 11 and the second sealing resin layer 12 are bonded together. Made by. Alternatively, the sealing resin sheet X may form the first sealing resin layer 11 on the base material and form the second sealing resin layer 12 on the first sealing resin layer 11. Alternatively, the sealing resin sheet X may form the second sealing resin layer 12 on the base material and form the first sealing resin layer 11 on the second sealing resin layer 12.

The first sealing resin layer 11 can be formed, for example, as follows. First, the first thermosetting composition is prepared by blending each of the above-mentioned components in a predetermined ratio with respect to the first thermosetting composition. If necessary, a solvent such as methyl ethyl ketone is further added to the composition. Then, the composition is applied onto a substrate such as a release sheet to form a coating film, and then the coating film is dried by heating. In this way, the first sealing resin layer 11 having a sheet shape and being in a semi-cured state can be formed.

The second sealing resin layer 12 can be formed, for example, as follows. First, the second thermosetting composition is prepared by blending each of the above-mentioned components in a predetermined ratio with respect to the second thermosetting composition. If necessary, a solvent such as methyl ethyl ketone is further added to the composition. Then, the composition is applied onto a substrate such as a release sheet to form a coating film, and then the coating film is dried by heating. In this way, the second sealing resin layer 12 having a sheet shape and being in a semi-cured state can be formed.

The sealing resin sheet X is produced by, for example, laminating the first sealing resin layer 11 and the second sealing resin layer 12 formed as described above.

In the sealing resin sheet X, the thickness of the first sealing resin layer 11 is, for example, 10 μm or more, preferably 25 μm or more, and more preferably 30 μm or more. The thickness of the first sealing resin layer 11 is, for example, 3000 μm or less, preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 300 μm or less, and particularly preferably 100 μm or less.

The thickness of the second sealing resin layer 12 is, for example, 10 μm or more, preferably 30 μm or more, and more preferably 50 μm or more. The thickness of the second sealing resin layer 12 is, for example, 3000 μm or less, preferably 1000 μm or less, and more preferably 500 μm or less.

The ratio of the thickness of the second sealing resin layer 12 to the thickness of the first sealing resin layer 11 is preferably 0.4 or more, more preferably 0.7 or more, still more preferably 1 or more. The ratio is preferably 12 or less, more preferably 11 or less, still more preferably 10 or less.

The thickness of the sealing resin sheet X is, for example, 20 μm or more, preferably 30 μm or more, and more preferably 50 μm or more. The thickness of the sealing resin sheet X is, for example, 6000 μm or less, preferably 3000 μm or less, more preferably 1500 μm or less, still more preferably 1000 μm or less, particularly preferably 500 μm or less, and most preferably 300 μm or less.

The sealing resin sheet X has a warp recovery rate represented by the following formula (1) in a warp recovery evaluation test in which the following first treatment, first measurement, second treatment, and second measurement are carried out. R is 80% or more, preferably 82% or more.

First treatment: A laminate sample comprising a 42-alloy plate having a size of 90 mm × 90 mm × 150 μm in thickness and a sealing resin sheet X bonded to the entire one surface in the thickness direction of the 42 alloy plate is prepared as 150. After heating at ° C. for 1 hour, let stand at 25 ° C. for 1 hour.
First measurement: The maximum value of the distance between the mounting surface on which the laminated body sample is placed and the edge of the laminated body sample with the 42 alloy plate of the laminated body sample facing down is set. 1 Measure as the warp length D1.
Second treatment: The laminated body sample is allowed to stand on the surface of a hot plate at 100 ° C. for 1 minute.
Second measurement: Maximum value of the distance between the surface of the heating plate and the edge of the laminated body sample (when the laminated body sample is curved in such a manner that the edge of the laminated body sample is lifted from the heating plate). The maximum distance in the vertical direction between the surface of the heating plate and the lower surface of the edge of the laminated body sample) is measured as the second warp length D2.

Equation (1): R = [(D1-D2) / D1] × 100

The second warp length D2 is preferably 2 mm or less, more preferably 1.8 mm or less, still more preferably 1.5 mm or less.

The warp recovery rate R is preferably 120% or less, more preferably 110% or less. When the warp length D2 takes a negative value, the warp recovery rate R exceeds 100%. At the time of the second measurement, when the inner region surrounded by the entire circumference of the edge of the laminated body sample is lifted from the heating plate and the laminated body sample is curved, the lower surface of the inner region and the surface of the heating plate are used. The length obtained by adding a negative sign to the maximum distance between the two in the vertical direction is defined as the second warp length D2.

Further, in the sealing resin sheet X, the following entry length L shown in the entry length evaluation test in which the following first step to the fourth step is carried out is preferably 50 μm or less, more preferably 30 μm or less. .. The approach length L is preferably 0 μm or more.

First step: A glass substrate and a dummy chip having a size of 3 mm × 3 mm × thickness of 200 μm are provided, and the dummy chip is opposed to the glass substrate through a gap through a bump on the glass substrate. A dummy chip mounting substrate having a length from the glass substrate to the dummy chip in the gap of 20 μm is prepared.
Second step: In a state where the first sealing resin layer 11 side of the sealing resin sheet X is in contact with the dummy chip on the glass substrate, the sealing resin sheet X is vacuumed at a temperature of 65 ° C. by a vacuum plate press. The first sealing resin layer 11 that presses against the glass substrate under the conditions of a degree of 1.6 kPa or less, a pressing force of 0.1 MPa, and a pressurizing time of 40 seconds and adheres to the glass substrate around the dummy chip is used. Close the open edge of the void.
Third step: After the second step, the sealing resin sheet X is thermally cured by heating at 150 ° C. for 1 hour under atmospheric pressure.
Fourth step: After the third step, the entry length L of the sealing resin sheet X into the void is measured.

FIG. 2 shows a method of sealing an electronic component chip on a base material using a sealing resin sheet X.

In this method, first, as shown in FIG. 2A, a sealing resin sheet X is prepared (preparation step).

Next, as shown in FIG. 2B, the work W and the sealing resin sheet X are arranged between the first press plate P1 and the second press plate P2 provided in the flat plate press machine (arrangement step).

The work W includes a substrate S and a plurality of chips 21. The substrate S is a base material that is later separated into a single mounting substrate, and has a mounting surface Sa. The mounting surface Sa is provided with terminals (not shown) for mounting. The chip 21 is an electronic component chip such as a semiconductor chip, and has a main surface 21a and a side surface 21b. The main surface 21a is provided with terminals for external connection (not shown). The chip 21 is mounted on the substrate S via the bump electrode 22 in a state of facing the substrate S via the gap G. Each bump electrode 22 is interposed between a terminal provided on the mounting surface Sa of the substrate S and a terminal provided on the main surface 21a of the chip 21 to electrically connect the substrate S and the chip 21. ing.

The separation distance between the substrate S and the chip 21 is such that the separation distance between the substrate S and the chip 21 is, for example, 10 μm or more, preferably 13 μm or more, and more preferably 15 μm or more. The separation distance is, for example, 60 μm or less, preferably 55 mm or less, and more preferably 50 μm or less.

Further, the plurality of chips 21 are mounted on the mounting surface Sa of the substrate S at intervals in the surface direction. The distance between the adjacent chips 21 is, for example, 50 μm or more, preferably 100 μm or more, and more preferably 200 μm or more. The distance between the adjacent chips 21 is, for example, 10 mm or less, preferably 5 mm or less, and more preferably 1 mm or less.

In this step, the work W is placed on the first press plate P1 so that the substrate S is in contact with the first press plate P1. The sealing resin sheet X is laminated with respect to the work W so that the first sealing resin layer 11 is in contact with the chip 21 of the work W.

Next, as shown in FIG. 2C, the sealing resin sheet X and the work W are pressed in the thickness direction by the first press plate P1 and the second press plate P2 (pressing step). Specifically, the sealing resin sheet X is pressed toward the substrate S while being heated and softened in a state where the first sealing resin layer 11 side of the sealing resin sheet X is in contact with the chip 21 on the substrate S.

The press pressure is, for example, 0.01 MPa or more, preferably 0.05 MPa or more. The press pressure is, for example, 10 MPa or less, preferably 5 MPa or less. The press time is, for example, 0.3 minutes or more, preferably 0.5 minutes or more. The press time is, for example, 10 minutes or less, preferably 5 minutes or less. The heating temperature during pressing is, for example, 40 ° C. or higher, preferably 60 ° C. or higher. The heating temperature is, for example, 100 ° C. or lower, preferably 95 ° C. or lower.

In this step, the sealing resin sheet X is deformed corresponding to the outer shape of the chip 21 while maintaining the B stage, and covers the side surface 21b of the chip 21 of each chip 21 while being formed with the chip 21 in a plan view. It contacts the mounting surface Sa of the non-overlapping substrate S. The open edge of the gap G is closed by the first sealing resin layer 11 that is in close contact with the substrate S around the chip 21.

In the configuration in which the first sealing resin layer 11 contains the layered silicate compound, as described above, the pressing force is applied to the first sealing resin layer 11 while thickening the first sealing resin layer 11. It is suitable for developing thixotropic properties that make the viscosity lower when it is received than when it is not received. Therefore, in this step, the sealing resin sheet X is deformed by the first sealing resin layer 11 together with the second sealing resin layer 12 softening and flowing under the pressing force to follow the outer shape of the chip 21. Suitable for doing.

The deformed sealing resin sheet X is allowed to slightly enter the gap G between the substrate S and the chip 21 of the chip 21. Specifically, the sealing resin sheet X is allowed to have an entry length L'(see FIG. 3C) that has entered the gap G with reference to the side surface 21b of the chip 21. The approach length L'is preferably 50 μm or less, more preferably 30 μm or less. The entry length L'is preferably −20 μm or more, more preferably −10 μm or more, still more preferably −5 μm or more.

Next, the work W sealed by the sealing resin sheet X is taken out from the flat plate press, and then the sealing resin sheet X is heated and cured as shown in FIG. 2D (curing step).

The heating temperature (cure temperature) is, for example, 100 ° C. or higher, preferably 120 ° C. or higher. The heating temperature (cure 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 less, preferably 120 minutes or less.

In the curing step, since the first sealing resin layer 11 contains the layered silicate compound, the decrease in viscosity due to the temperature rise is suppressed, and further entry into the void G is suppressed. On the other hand, the viscosity of the second sealing resin layer 12 is once lowered and fluidized before curing, and the exposed surface on the opposite side of the first sealing resin layer 11 is flattened.

The entry length L (see FIG. 3D) in the void G in the cured sealing resin sheet X is preferably 50 μm or less, more preferably 30 μm or less. The approach length L is preferably 0 μm or more.

Next, surface treatment such as laser printing (printing by laser marking) is performed on the surface of the sealing resin (cured sealing resin sheet X) for each electronic component chip.

After that, the cured encapsulation resin sheet X and the substrate S are cut along a predetermined cutting schedule line by blade dicing, and are individualized into an electronic component chip resin encapsulation body.

In the sealing resin sheet X, the warp recovery rate R shown in the warp recovery evaluation test is 80% or more, preferably 82% or more, and preferably 120% or less, more preferably 120% or less, as described above. Is 110% or less. Such a configuration is suitable for suppressing the height difference of the work surface in the manufacturing process of the electronic component chip resin encapsulation body in which the encapsulation resin sheet X is used. Suppressing the height difference on the surface of the work is suitable for accurately performing surface treatment such as laser printing for each electronic component chip on the surface of the encapsulating resin on the entire work.

In the sealing resin sheet X, the second warp length D2 shown in the warp recovery evaluation test is preferably 2 mm or less, more preferably 1.8 mm or less, still more preferably 1.5 mm or less, as described above. .. Such a configuration suppresses the height difference of the surface of the work W in the manufacturing process of the electronic component chip resin encapsulation body in which the present encapsulation resin sheet is used, and the encapsulation resin (encapsulating resin sheet after curing). X) Suitable for processing the surface with high accuracy.

In the press process described above with reference to FIG. 2C, the second sealing resin layer 12 of the sealing resin sheet X is fluidized by receiving a pressing force, and the exposed surface on the opposite side of the first sealing resin layer 11 Flattening progresses. Further, in the pressing step, as described above, in the sealing resin sheet X, the first sealing resin layer 11 together with the second sealing resin layer 12 softens and flows under the pressing force, and the electronic component chip Suitable for deformation that follows the outer shape of. In such a pressing step, it is allowed that a part of the sealing resin sheet X slightly enters the gap G between the substrate S and the chip 21 of the chip 21. Then, in the curing step described above with reference to FIG. 2D, as described above, the first sealing resin layer 11 is suppressed from being fluidized due to the decrease in viscosity due to the temperature rise, and excessive entry into the void G. Is suppressed. That is, the sealing resin sheet X is suitable for controlling the length of the sealing resin entering into the gap G between the substrate S and the chip 21 in the process of manufacturing the electronic component chip resin encapsulation body.

In the sealing resin sheet X, as described above, the tensile storage elastic modulus (first tensile storage elastic modulus) at 25 ° C. that the first sealing resin layer 11 has after heat treatment at 150 ° C. for 1 hour is determined. It is preferably 3.5 GPa or more, more preferably 3.8 GPa or more, and further preferably 4 GPa or more. In such a configuration, in the manufacturing process of the electronic component chip resin encapsulation body in which the encapsulating resin sheet X is used, cracks, chipping, etc. are formed on the base material on which the electronic component chip is mounted at the time of individualization by blade dicing. Suitable for suppressing the occurrence of damage.

In the sealing resin sheet X, as described above, the glass transition temperature of the second sealing resin layer 12 after the heat treatment at 150 ° C. for 1 hour is preferably 100 ° C. or lower, more preferably 95 ° C. or lower. More preferably, it is 90 ° C. or lower. With such a configuration, when the sealing resin sheet X after heat curing is warped, the sealing resin sheet is once softened by heating at about 100 ° C. to reduce the warp of the sheet. Suitable for.

In the sealing resin sheet X, as described above, the tensile storage elastic modulus (second tensile storage elastic modulus) at 100 ° C. that the second sealing resin layer 12 has after heat treatment at 150 ° C. for 1 hour is determined. It is preferably 0.5 GPa or less, more preferably 0.4 GPa or less, still more preferably 0.38 GPa or less. With such a configuration, when the sealing resin sheet X after heat curing is warped, the sealing resin sheet is once softened by heating at about 100 ° C. to reduce the warp of the sheet. Suitable for.

In the sealing resin sheet X, as described above, the ratio of the second tensile storage elastic modulus to the first tensile storage elastic modulus is preferably 0.12 or less, more preferably 0.1 or less, still more preferably 0. It is 08 or less. Such a configuration is suitable for both the above-mentioned suppression of warpage and the above-mentioned suppression of damage.

In the sealing resin sheet X, as described above, the ratio of the thickness of the second sealing resin layer 12 to the thickness of the first sealing resin layer 11 is preferably 0.4 or more, more preferably 0. 7 or more, more preferably 1 or more. Such a configuration is a gap between the substrate S and the electronic component chip 21 in the manufacturing process of the electronic component chip resin encapsulation body including the pressing step and the curing step as described above in which the sealing resin sheet X is used. Suitable for controlling the penetration length of the sealing resin into G.

In the sealing resin sheet X, the first sealing resin layer 11 and the second sealing resin layer 12 preferably contain an epoxy resin, and the softening point of the epoxy resin is preferably 50 ° C. or higher, more preferably. Is 60 ° C. or higher, more preferably 72 ° C. or higher, particularly preferably 75 ° C. or higher, and preferably 130 ° C. or lower, more preferably 110 ° C. or lower, still more preferably 90 ° C. or lower. Such a configuration is suitable for ensuring the fluidity of the first and second sealing resin layers in the pressing process, thus shortening the time of the pressing process and the exposed surface of the second sealing resin layer in the pressing process. It is useful for flattening (the surface of the second sealing resin layer opposite to the first sealing resin layer).

In the sealing resin sheet X, preferably, the first sealing resin layer 11 and the second sealing resin layer 12 contain a phenol resin together with the epoxy resin. Such a configuration is suitable for the present encapsulation resin sheet to exhibit high heat resistance and high chemical resistance after its curing, and therefore suitable for forming a encapsulant having excellent encapsulation reliability. ..

Further, in the present invention, the sealing resin sheet X may have a single-layer structure of the first sealing resin layer 11 without providing the second sealing resin layer 12.

Although the present invention will be described in more detail with reference to Examples below, the present invention is not limited to the Examples. In addition, specific numerical values such as the compounding amount (content), physical property values, parameters, etc. used in the following description are the compounding amounts corresponding to those described in the above-mentioned "form for carrying out the invention" (forms for carrying out the invention). It can be replaced with the upper limit (value defined as "less than or equal to" or "less than") or lower limit (value defined as "greater than or equal to" or "excess") such as content), physical property value, parameter, etc. can.

[Production Examples 1 to 5]
Each of the first resin films of Production Examples 1 to 5 for forming the first sealing resin layer was prepared as follows. First, each component was mixed according to the formulation shown in Table 1 to prepare a composition (varnish) (in Table 1, the unit of each numerical value representing the composition is a relative "part by mass"). Next, the composition was applied onto a polyethylene terephthalate film (PET film) having a thickness of 50 μm whose surface was mold-released with silicone to form a coating film. Next, this coating film was heated and dried at 120 ° C. for 2 minutes to prepare a first resin film having a thickness of 50 μm on a PET film (the formed first resin film is in the B stage state).

[Production Examples 6-9]
Each of the second resin films of Production Examples 6 to 9 for forming the second sealing resin layer was prepared as follows. First, each component was mixed according to the formulation shown in Table 2 to prepare a composition (varnish) (in Table 2, the unit of each numerical value representing the composition is a relative "part by mass"). Next, the composition was applied onto a PET film having a thickness of 50 μm whose surface was subjected to a silicone mold release treatment to form a coating film. Next, this coating film was heated and dried at 120 ° C. for 2 minutes to form a resin film having a thickness of 52.5 μm on the PET film (the formed resin film is in the B stage state). Then, four resin films having a thickness of 52.5 μm formed as described above from varnishes having the same composition were bonded together to prepare a second resin film having a thickness of 210 μm.

The components used in Production Examples 1 to 9 are as follows.
Epoxy resin E1: "YSLV-80XY" manufactured by Nippon Steel Chemical Co., Ltd. (bisphenol F type epoxy resin, high molecular weight epoxy resin, epoxy equivalent 200 g / eq., Solid at room temperature, softening point 80 ° C)
Epoxy resin E2: "EPICLON EXA-4850-150" manufactured by DIC (bisphenol A type epoxy resin, molecular weight 900, epoxy equivalent 450 g / eq., Liquid at room temperature)
Phenol resin F1: "LVR-8210DL" manufactured by Gunei Chemical Co., Ltd. (Novolak type phenol resin, latent curing agent, hydroxyl equivalent 104 g / eq., Solid at room temperature, softening point 60 ° C)
Phenol resin F2: "MEHC-7851SS" manufactured by Meiwa Kasei Co., Ltd. (Phenol aralkyl resin, latent curing agent, hydroxyl group equivalent 201-220 g / eq., Solid at room temperature, softening point 64 to 85 ° C)
Acrylic resin: "HME-2006M" manufactured by Negami Kogyo Co., Ltd. (Carboxyl group-containing acrylic resin, acid value 32 mgKOH / g, weight average molecular weight 1.29 million, glass transition temperature (Tg) -13.9 ° C, solid content concentration 20 mass % Methyl ethyl ketone solution)
Silane coupling agent: "KBM-403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
Layered silicate compound: "Esben NX" manufactured by Hojun Co., Ltd. (organized bentonite whose surface is modified with dimethyl distearyl ammonium)
Inorganic filler f1: "FB-8SM" manufactured by Denka Co., Ltd. (spherical silica particles, average particle diameter 7.0 μm, no surface treatment)
Inorganic filler f2: Surface treatment of "SC220G-SMJ" (silica particles, average particle size 0.5 μm) manufactured by Admatex with 3-methacryloxypropyltrimethoxysilane ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.). (Silane coupling agent used for surface treatment is 1 part by mass with respect to 100 parts by mass of silica particles)
Curing accelerator: "2PHZ-PW" (2-phenyl-4,5-dihydroxymethylimidazole) manufactured by Shikoku Chemicals Corporation
Solvent: Methyl ethyl ketone (MEK)
Carbon black: # 20, manufactured by Mitsubishi Chemical Corporation, average particle size 50 nm

[Examples 1 to 4 and Comparative Examples 1 to 3]
Resin sheets for sealing of Examples 1 to 4 and Comparative Examples 1 to 3 were prepared. Specifically, by laminating the first resin film (first sealing resin layer) and the second resin film (second sealing resin layer) in the combination shown in Table 3, a sealing resin having a thickness of 260 μm is used. A sheet was prepared.

<Measurement of tensile storage elastic modulus>
The first sealing resin layer after curing and the second sealing resin layer after curing of the sealing resin sheets of Examples 1 to 4 and Comparative Examples 1 to 3 were measured at 25 ° C. by dynamic viscoelasticity measurement. The tensile storage elastic modulus and the tensile storage elastic modulus at 100 ° C. were measured. A dynamic viscoelasticity measuring device (trade name "RSA-G2", manufactured by TA Instruments) was used for the measurement. The sample piece for measurement (sample piece of the first sealing resin layer, sample piece of the second sealing resin layer) was cured by heat treatment at 150 ° C. for 1 hour, and had a width of 10 mm and a length of 40 mm. Has a size. In the measurement, the initial distance between the chucks for holding the sample piece is 20 mm, the measurement mode is the tension mode, the measurement temperature range is -10 ° C to 260 ° C, the temperature rise rate is 10 ° C / min, and the frequency. Was set to 1 Hz, and the dynamic strain was set to 0.05%. The tensile storage elastic modulus M1 (first tensile storage elastic modulus) at 25 ° C. and the tensile storage elastic modulus M1'at 100 ° C. measured for the first sealed resin layer after curing, and the second sealing after curing. Table 3 shows the tensile storage elastic modulus M2 at 25 ° C. and the tensile storage elastic modulus M2'(second tensile storage elastic modulus) at 100 ° C. measured for the resin layer. Table 3 also shows the ratio of the tensile storage elastic modulus M2'to the tensile storage elastic modulus M1 (M2'/ M1) and the ratio of the tensile storage elastic modulus M2 to the tensile storage elastic modulus M2'(M2 / M2'). ..

<Measurement of glass transition temperature>
Dynamic viscoelasticity measurement was performed to measure the glass transition temperature of the first sealed resin layer after curing and the second sealed resin layer after curing in each of the encapsulating resin sheets of Examples 1 to 4 and Comparative Examples 1 to 3. It was determined by the maximum value of the loss tangent (tan δ) measured using. The sample piece for measurement (sample piece of the first sealing resin layer, sample piece of the second sealing resin layer) was cured by heat treatment at 150 ° C. for 1 hour. A dynamic viscoelasticity measuring device (trade name "RSA-G2", manufactured by TA Instruments) was used for the measurement (the measurement conditions are the same as the above-mentioned measurement conditions for the measurement of the tensile storage elastic modulus). The results are shown in Table 3.

<Evaluation of approach length>
For each of the sealing resin sheets of Examples 1 to 4 and Comparative Examples 1 to 3, the electronic component chips mounted on the substrate are sealed with the electronic component chips facing the substrate through the voids. The length of entry into the gap between the base material and the electronic component chip in the cured state was measured.

First, as shown in FIG. 3A, a sample sheet X'with a length of 10 mm, a width of 10 mm, and a thickness of 150 μm was prepared from the sealing resin sheets of each Example and each Comparative Example. The sample sheet X'includes the first sealing resin layer 11 and the second sealing resin layer 12 in order in the thickness direction.

On the other hand, a dummy chip mounting board was prepared as the work W (first step). The dummy chip mounting substrate includes a glass substrate S and a dummy chip 21'with a size of 3 mm × 3 mm × thickness of 200 μm, and the dummy chip 21'is opposed to the substrate S via a gap G. It is bonded to the substrate S via the bump 22 and the length from the substrate S to the dummy chip 21'in the gap G is 20 μm.

Next, as shown in FIG. 3B, the work W and the sample sheet X'described above were arranged between the first press plate P1 and the second press plate P2 provided in the flat plate press machine.

Next, as shown in FIG. 3C, the dummy chip 21'on the substrate S is pressed by the sample sheet X'with a vacuum plate press at a temperature of 65 ° C., a vacuum degree of 1.6 kPa or less, a pressing force of 0.1 MPa, and a pressing force. Sealing was performed under a sealing condition with a pressure time of 40 seconds (second step).

Next, as shown in FIG. 3D, the sample sheet X'was cured by heating at 150 ° C. for 1 hour under atmospheric pressure (third step).

Then, as shown in the enlarged view of FIG. 3D, the sealing resin derived from the sample sheet X'is formed in the gap G between the dummy chip 21'and the substrate S from the side surface 21b'with reference to the side surface 21b' of the dummy chip 21'. The length into which the first encapsulating resin layer 11) entered was measured as the entry length L (fourth step). The results are shown in Table 3 (when the approach length L takes a negative value, it means that a space protruding outward from the side surface 21b'of the dummy chip 21'(see the thick broken line in FIG. 3D) is formed. The absolute value of "minus" corresponds to the protruding length of the space).

<Evaluation of warpage>
The following first treatment, first measurement, second treatment, and second measurement were carried out in this order.

First, in the first treatment, a laminated body sample including a 42 alloy plate having a size of 90 mm × 90 mm × thickness 150 μm and a sealing resin sheet bonded to the entire one surface in the thickness direction of the 42 alloy plate is prepared. , The mixture was heated at 150 ° C. for 1 hour and then allowed to stand at 25 ° C. for 1 hour.

Next, in the first measurement, the maximum value of the distance between the mounting surface on which the laminated body sample is placed with the 42 alloy plate of the laminated body sample on the lower side and the edge of the laminated body sample is warped. Measured as length D1.

Next, in the second treatment, the laminated body sample was allowed to stand on the surface of a hot plate at 100 ° C. for 1 minute.

Next, in the warp measurement, the maximum value of the distance between the surface of the heating plate and the edge of the laminated body sample was measured as the warp length D2. The results are shown in Table 3. Table 3 also shows the warp recovery rate R (%) represented by the following formula (1).

Equation (1): R = [(D1-D2) / D1] × 100

<Damage to the board>
For each of the sealing resin sheets of Examples 1 to 4 and Comparative Examples 1 to 3, the damage suppressing effect on the substrate was investigated as follows.

First, a sealing resin sheet (thickness 260 μm) of the same size was bonded to an alumina substrate having a size of 100 mm × 100 mm × thickness of 200 μm to prepare a sample work. Specifically, a resin sheet for encapsulation is applied to the entire one surface of the alumina substrate in the thickness direction by a vacuum plate press at a temperature of 65 ° C., a vacuum degree of 1.6 kPa or less, a pressing force of 0.1 MPa, and a pressurizing time. They were pasted together under the condition of 40 seconds.

Next, the sample work was heated at 150 ° C. for 1 hour under atmospheric pressure to cure the sealing resin sheet in the sample work.

Next, by blade dicing using a dicing device (trade name "DFD651", manufactured by Disco Corporation) and a dicing blade (trade name "GIA850", manufactured by Disco Corporation), the sample work is individually separated into a size of 1 mm x 1 mm. Multiple sample pieces were obtained. In this dicing, the rotation speed of the dicing blade was set to 30,000 rpm.

Next, the side surface of the substrate in the sample piece was observed with an optical microscope, and the presence or absence of damage such as cracks and chipping in the substrate was examined (the number of sample pieces observed was 30). Table 3 shows the number of sample pieces whose substrate was damaged among the 30 sample pieces observed.

X Sealing resin sheet 11 1st sealing resin layer 12 2nd sealing resin layer W Work S Substrate Sa Mounting surface 21 Chip 21a Main surface 21b Side surface 22 Bump electrode P1 1st press flat plate P2 2nd press flat plate

Claims (8)

A sealing resin sheet containing a thermosetting resin.
In the warp recovery evaluation test in which the following first treatment, first measurement, second treatment, and second measurement are carried out in this order, the warp recovery rate R represented by the following formula (1) is 80%. A resin sheet for sealing, characterized by the above.
First treatment: A laminate sample comprising a 42-alloy plate having a size of 90 mm × 90 mm × 150 μm and the sealing resin sheet bonded to the entire one surface of the 42 alloy plate in the thickness direction is prepared as 150. After heating at ° C. for 1 hour, let stand at 25 ° C. for 1 hour.
First measurement: The maximum value of the distance between the mounting surface on which the laminated body sample is placed and the edge of the laminated body sample with the 42 alloy plate of the laminated body sample facing down is set. 1 Measure as the warp length D1.
Second treatment: The laminated body sample is allowed to stand on the surface of a hot plate at 100 ° C. for 1 minute.
Second measurement: The maximum value of the distance between the surface of the heating plate and the edge of the laminated body sample is measured as the second warp length D2.
Equation (1): R = [(D1-D2) / D1] × 100 The sealing resin sheet according to claim 1, wherein the second warp length D2 is 2 mm or less. The sealing resin sheet includes a first sealing resin layer and a second sealing resin layer in order in the thickness direction.
The first sealing resin layer contains a first thermosetting resin and a layered silicate compound, and contains the first thermosetting resin.
The sealing resin sheet according to claim 1 or 2, wherein the second sealing resin layer contains a second thermosetting resin. The sealing resin according to claim 3, wherein the following entry length L shown in the entry length evaluation test in which the following first step to the fourth step is carried out is 0 μm or more and 50 μm or less. Sheet.
First step: A glass substrate and a dummy chip having a size of 3 mm × 3 mm × thickness of 200 μm are provided, and the dummy chip is opposed to the glass substrate through a gap through a bump on the glass substrate. A dummy chip mounting substrate having a length from the glass substrate to the dummy chip in the gap of 20 μm is prepared.
Second step: With the dummy chip on the glass substrate in contact with the first sealing resin layer side of the sealing resin sheet, the sealing resin sheet is evacuated at a temperature of 65 ° C. by a vacuum plate press. The first sealing resin layer, which is pressed toward the glass substrate under the conditions of a degree of 1.6 kPa or less, a pressing force of 0.1 MPa, and a pressurizing time of 40 seconds, is in close contact with the glass substrate around the dummy chip. Close the open edge of the void.
Third step: After the second step, the sealing resin sheet is cured by heating at 150 ° C. for 1 hour under atmospheric pressure.
Fourth step: After the third step, the entry length L of the sealing resin sheet into the void is measured. The seal according to claim 3 or 4, wherein the first sealing resin layer has a first tensile storage elastic modulus of 3.5 GPa or more at 25 ° C. after heat treatment at 150 ° C. for 1 hour. Resin sheet for stopping. The sealing according to any one of claims 3 to 5, wherein the second sealing resin layer has a glass transition temperature of 100 ° C. or lower after heat treatment at 150 ° C. for 1 hour. Resin sheet. Any one of claims 3 to 6, wherein the second sealing resin layer has a second tensile storage elastic modulus of 0.5 GPa or less at 100 ° C. after heat treatment at 150 ° C. for 1 hour. The sealing resin sheet described in 1. 100 of the second encapsulation resin layer after heat treatment at 150 ° C. for 1 hour with respect to the first tensile storage elastic modulus of the first encapsulation resin layer after heat treatment at 150 ° C. for 1 hour. The sealing resin sheet according to any one of claims 3 to 7, wherein the ratio of the second tensile storage elastic modulus at ° C. is 0.12 or less.

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