Adhesive composition, film-like adhesive, adhesive sheet, and method for manufacturing semiconductor device

Abstract

To provide an adhesive composition capable of suppressing bleeding while having good embedding properties during thermocompression bonding.SOLUTION: The adhesive composition contains a thermosetting resin, a curing agent, an elastomer, and an inorganic filler. The curing agent includes a phenol resin having an alicyclic ring. The content of the elastomer is 10 to 80 parts by mass with respect to 100 parts by mass of the thermosetting resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an adhesive composition, a film-like adhesive, an adhesive sheet, and a method for producing a semiconductor device. [Background technology]

[0002] Conventionally, silver paste has been mainly used to bond semiconductor chips to support members for mounting the semiconductor chips. However, with the recent trend toward smaller and more integrated semiconductor chips, there has been a demand for smaller and more precise support members to be used. On the other hand, when silver paste is used, problems such as wire bonding defects due to paste overflow or tilting of the semiconductor chip, difficulty in controlling film thickness, and void formation can occur.

[0003] For this reason, in recent years, film adhesives have been used to bond semiconductor chips to support members (see, for example, Patent Document 1). When using an adhesive sheet comprising a dicing tape and a film adhesive laminated on the dicing tape, the film adhesive is attached to the back surface of a semiconductor wafer, and the semiconductor wafer is then diced into individual pieces, thereby obtaining semiconductor chips with the film adhesive. The obtained semiconductor chips with the film adhesive can be attached to a support member via the film adhesive and bonded by thermocompression bonding. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-053240 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as the size of the semiconductor chip becomes smaller, the force applied per unit area during thermocompression bonding increases, and a phenomenon known as bleeding may occur, in which the film adhesive protrudes from the semiconductor chip.

[0006] Furthermore, when a film adhesive is used as a wire-embedded film adhesive (FOW) or a semiconductor chip-embedded film adhesive (FOD), high fluidity is required during thermocompression bonding to improve embeddability. This tends to further increase the frequency and amount of bleeding. In some cases, bleeding may even occur on the top surface of the semiconductor chip, potentially leading to electrical or wire bonding defects.

[0007] The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide an adhesive composition that has good embedding properties during thermocompression bonding and is capable of suppressing bleeding. [Means for solving the problem]

[0008] One aspect of the present invention provides an adhesive composition. The adhesive composition contains a thermosetting resin, a curing agent, an elastomer, and an inorganic filler. The curing agent contains a phenolic resin having an alicyclic ring. The content of the elastomer is 10 to 80 parts by mass per 100 parts by mass of the thermosetting resin. Such an adhesive composition can exhibit good embedding properties during thermocompression bonding while suppressing bleeding.

[0009] The thermosetting resin may be an epoxy resin, and the epoxy resin may include a bisphenol F type epoxy resin.

[0010] The elastomer may be an acrylic resin.

[0011] The inorganic filler may be silica. The content of the inorganic filler may be 25 mass % or more based on the total amount of the adhesive composition.

[0012] The total content of the thermosetting resin, curing agent, elastomer, and inorganic filler may be 95 mass % or more based on the total amount of the adhesive composition.

[0013] The adhesive composition may further contain a curing accelerator.

[0014] The adhesive composition may be used in a semiconductor device in which a first semiconductor element is wire-bonded onto a substrate via a first wire and a second semiconductor element is pressure-bonded onto the first semiconductor element, for pressure-bonding the second semiconductor element and embedding at least a portion of the first wire.

[0015] The present invention may further relate to an application of a composition containing a thermosetting resin, a curing agent, and an elastomer, wherein the curing agent includes a phenolic resin having an alicyclic ring, as an adhesive or for producing an adhesive, used in a semiconductor device in which a first semiconductor element is wire-bonded onto a substrate via a first wire and a second semiconductor element is pressure-bonded onto the first semiconductor element, for crimping a second semiconductor element and embedding at least a portion of the first wire.

[0016] Another aspect of the present invention provides a film-like adhesive obtained by forming the above-mentioned adhesive composition into a film.

[0017] Another aspect of the present invention provides an adhesive sheet comprising a substrate and the above-described film adhesive provided on the substrate.

[0018] The substrate may be a dicing tape. In this specification, an adhesive sheet whose substrate is a dicing tape may be referred to as an "integrated dicing-die bonding adhesive sheet."

[0019] The adhesive sheet may further include a protective film laminated on the surface of the film adhesive opposite to the substrate.

[0020] Another aspect of the present invention provides a method for manufacturing a semiconductor device, comprising: a wire bonding process for electrically connecting a first semiconductor element to a substrate via a first wire; a laminating process for applying the above-mentioned film-like adhesive to one side of a second semiconductor element; and a die bonding process for embedding at least a portion of the first wire in the film-like adhesive by pressing the second semiconductor element with the film-like adhesive applied via the film-like adhesive.

[0021] The semiconductor device may be a wire-embedded semiconductor device in which a first semiconductor chip is wire-bonded onto a semiconductor substrate via a first wire and a second semiconductor chip is pressure-bonded onto the first semiconductor chip via an adhesive film, so that at least a portion of the first wire is embedded in the adhesive film, or may be a chip-embedded semiconductor device in which the first wire and the first semiconductor chip are embedded in the adhesive film. [Effects of the Invention]

[0022] The present invention provides an adhesive composition that exhibits good embeddability during thermocompression bonding while suppressing bleeding. Therefore, a film adhesive formed from the adhesive composition can be useful as a film-over-die (FOD) adhesive for embedding semiconductor chips or a film-over-wire (FOW) adhesive for embedding wires. The present invention also provides an adhesive sheet and a method for manufacturing a semiconductor device using such a film adhesive. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic cross-sectional view showing a film-like adhesive according to one embodiment. [Figure 2] FIG. 1 is a schematic cross-sectional view showing an adhesive sheet according to one embodiment. [Figure 3] FIG. 10 is a schematic cross-sectional view showing an adhesive sheet according to another embodiment. [Figure 4] 1 is a schematic cross-sectional view showing a semiconductor device according to an embodiment; [Figure 5] 1A to 1C are schematic cross-sectional views showing a series of steps in a method for manufacturing a semiconductor device according to an embodiment. [Figure 6] 1A to 1C are schematic cross-sectional views showing a series of steps in a method for manufacturing a semiconductor device according to an embodiment. [Figure 7] 1A to 1C are schematic cross-sectional views showing a series of steps in a method for manufacturing a semiconductor device according to an embodiment. [Figure 8] 1A to 1C are schematic cross-sectional views showing a series of steps in a method for manufacturing a semiconductor device according to an embodiment. [Figure 9] 1A to 1C are schematic cross-sectional views showing a series of steps in a method for manufacturing a semiconductor device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, although the present invention is not limited to the following embodiments.

[0025] In this specification, (meth)acrylic acid means acrylic acid or its corresponding methacrylic acid. The same applies to other similar expressions such as a (meth)acryloyl group.

[0026] [Adhesive composition] The adhesive composition according to this embodiment contains (A) a thermosetting resin, (B) a curing agent, (C) an elastomer, and (D) an inorganic filler. The adhesive composition is thermosetting and can reach a semi-cured (B-stage) state and then a fully cured (C-stage) state after a curing treatment.

[0027] <(A) Component: Thermosetting resin> From the viewpoint of adhesiveness, component (A) may be an epoxy resin. The epoxy resin may be any compound having an epoxy group in the molecule, and is not particularly limited. Examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, bisphenol F novolac epoxy resins, stilbene epoxy resins, triazine skeleton-containing epoxy resins, fluorene skeleton-containing epoxy resins, triphenolmethane epoxy resins, biphenyl epoxy resins, xylylene epoxy resins, biphenyl aralkyl epoxy resins, naphthalene epoxy resins, and epoxy resins having an alicyclic ring. These may be used alone or in combination of two or more. Among these, the epoxy resin may contain bisphenol F epoxy resin. When the epoxy resin contains bisphenol F epoxy resin, embeddability tends to be improved. Furthermore, from the viewpoint of fluidity, the epoxy resin may contain an epoxy resin having an alicyclic ring, and the epoxy resin having an alicyclic ring may be a dicyclopentadiene-type epoxy resin (an epoxy resin having a dicyclopentadiene structure).

[0028] The epoxy equivalent of component (A) is not particularly limited, but may be 90 to 600 g / eq, 100 to 500 g / eq, or 120 to 450 g / eq. When the epoxy equivalent of component (A) is within this range, good reactivity and flowability tend to be obtained. When component (A) contains a bisphenol F epoxy resin, the epoxy equivalent of the bisphenol F epoxy resin may be less than 180 g / eq, or 170 g / eq or 160 g / eq or less, from the viewpoint of embeddability. The epoxy equivalent of the bisphenol F epoxy resin may be 90 g / eq or more, 100 g / eq or more, or 120 g / eq or more.

[0029] <Component (B): Hardener> The component (B) contains a phenolic resin (B-1) having an alicyclic ring.

[0030] Component (B-1) is a compound having an alicyclic ring and a hydroxyl group in the molecule. The hydroxyl group may be bonded to the alicyclic ring or a site other than the alicyclic ring of the compound via a single bond or a linking group (e.g., an alkylene group, an oxyalkylene group, etc.). By including component (B-1) as a curing agent, it is possible to suppress bleeding while maintaining good embedding properties during thermocompression bonding.

[0031] The component (B-1) may be, for example, a phenol resin represented by the following general formula (1).

[0032] [ka]

[0033] In formula (1), E represents an alicyclic ring, G represents a single bond or an alkylene group, and R 1 each independently represents a hydrogen atom or a monovalent hydrocarbon group, n1 represents an integer of 1 to 10, and m represents an integer of 1 to 3.

[0034] The number of carbon atoms in E may be 4 to 12, 5 to 11, or 6 to 10. E may be a monocyclic or polycyclic ring, but is preferably a polycyclic ring, and more preferably a dicyclopentadiene ring. The alkylene group in G may be an alkylene group having 1 to 5 carbon atoms, such as a methylene group, ethylene group, propylene group, butylene group, or pentylene group. G is preferably a single bond. R 1 The monovalent hydrocarbon group in R may be, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group, an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as a pyridyl group. 1 is preferably a hydrogen atom.

[0035] The phenol resin represented by the general formula (1) may be a phenol resin represented by the following general formula (1a).

[0036] [ka]

[0037] In formula (1a), n1 has the same meaning as above.

[0038] Commercially available epoxy resins represented by general formula (1a) include, for example, J-DPP-85, J-DPP-95, and J-DPP-115 (all manufactured by JFE Chemical Corporation).

[0039] The hydroxyl equivalent of component (B-1) is not particularly limited, but may be 80 to 400 g / eq, 90 to 350 g / eq, or 100 to 300 g / eq. When the hydroxyl equivalent of component (B-1) is within this range, good reactivity and flowability tend to be obtained.

[0040] The content of component (B-1) may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total amount of the adhesive composition. When the content of component (B-1) is 5% by mass or more, based on the total amount of the adhesive composition, there is a tendency for the adhesive composition to have better embedding properties during thermocompression bonding while effectively suppressing bleeding. The content of component (B-1) may be 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total amount of the adhesive composition.

[0041] In addition to the component (B-1), the component (B) may further contain a phenolic resin (B-2) that does not have an alicyclic ring. Examples of the component (B-2) include novolak-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenols and / or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene with compounds having an aldehyde group such as formaldehyde under an acidic catalyst; phenol aralkyl resins, naphthol aralkyl resins, biphenyl aralkyl-type phenolic resins, and phenyl aralkyl-type phenolic resins synthesized from phenols such as phenol and / or naphthols and dimethoxy-paraxylene or bis(methoxymethyl)biphenyl; and the like. These may be used alone or in combination of two or more.

[0042] The hydroxyl equivalent of component (B-2) is not particularly limited, but may be 80 to 400 g / eq, 90 to 350 g / eq, or 100 to 300 g / eq. When the hydroxyl equivalent of component (B-1) is within this range, good reactivity and flowability tend to be obtained.

[0043] The content of component (B-1) may be 50 to 100% by mass, based on the total amount of component (B). The content of component (B-1) may be 60% by mass or more, or 70% by mass or more, based on the total amount of component (B). The content of component (B-2) may be 0 to 50% by mass, based on the total amount of component (B). The content of component (B-2) may be 40% by mass or less, or 30% by mass or less, based on the total amount of component (B).

[0044] When component (A) is an epoxy resin, the ratio of the epoxy equivalent of the epoxy resin to the hydroxyl equivalent of component (B) (epoxy equivalent of epoxy resin / hydroxyl equivalent of phenolic resin) may be 0.30 / 0.70 to 0.70 / 0.30, 0.35 / 0.65 to 0.65 / 0.35, 0.40 / 0.60 to 0.60 / 0.40, or 0.45 / 0.55 to 0.55 / 0.45 from the viewpoint of curability. When the equivalent ratio is 0.30 / 0.70 or more, more sufficient curability tends to be obtained. When the equivalent ratio is 0.70 / 0.30 or less, excessive viscosity can be prevented, and more sufficient fluidity can be obtained.

[0045] The total content of components (A) and (B) may be 30 to 70% by mass, based on the total amount of the adhesive composition. The total content of components (A) and (B) may be 33% by mass or more, 36% by mass or more, or 40% by mass or more, and may be 65% by mass or less, 60% by mass or less, or 55% by mass or less. When the total content of components (A) and (B) is 30% by mass or more, based on the total amount of the adhesive composition, adhesiveness tends to be improved. When the total content of components (A) and (B) is 70% by mass or less, based on the total amount of the adhesive composition, the viscosity can be prevented from becoming too low, and bleeding tends to be further suppressed.

[0046] <Component (C): Elastomer> The adhesive composition according to this embodiment contains an elastomer (C). The polymer constituting the elastomer (C) preferably has a glass transition temperature (Tg) of 50° C. or lower.

[0047] Examples of the component (C) include acrylic resins, polyester resins, polyamide resins, polyimide resins, silicone resins, butadiene resins, acrylonitrile resins, and modified versions of these resins.

[0048] The component (C) may contain an acrylic resin from the viewpoints of solubility in solvents and fluidity. Here, the acrylic resin refers to a polymer containing a structural unit derived from a (meth)acrylic acid ester. The acrylic resin is preferably a polymer containing a structural unit derived from a (meth)acrylic acid ester having a crosslinkable functional group such as an epoxy group, an alcoholic or phenolic hydroxyl group, or a carboxyl group as a structural unit. The acrylic resin may also be an acrylic rubber such as a copolymer of a (meth)acrylic acid ester and acrylonitrile.

[0049] The glass transition temperature (Tg) of the acrylic resin may be -50 to 50°C or -30 to 30°C. When the Tg of the acrylic resin is -50°C or higher, the flexibility of the adhesive composition tends to be prevented from becoming too high. This makes it easier to cut the film-like adhesive during wafer dicing, and prevents the occurrence of burrs. When the Tg of the acrylic resin is 50°C or lower, the flexibility of the adhesive composition tends to be suppressed from decreasing. This makes it easier to sufficiently fill voids when the film-like adhesive is attached to a wafer. It also makes it possible to prevent chipping during dicing due to a decrease in wafer adhesion. Here, the glass transition temperature (Tg) refers to a value measured using a TMA tester (TMA400Q, manufactured by TA Instruments).

[0050] The weight-average molecular weight (Mw) of the acrylic resin may be 100,000 to 3,000,000 or 500,000 to 2,000,000. When the Mw of the acrylic resin is within this range, it is possible to appropriately control the film-forming properties, film strength, flexibility, tackiness, etc., and it is also possible to achieve excellent reflowability and improved embeddability. Here, Mw refers to a value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

[0051] Commercially available acrylic resins include, for example, SG-70L, SG-708-6, WS-023 EK30, SG-280 EK23, and SG-P3 solvent-modified product (all manufactured by Nagase ChemteX Corporation).

[0052] The content of the (C) component is 10 to 80 parts by mass per 100 parts by mass of the (A) component. The content of the (C) component may be 20 parts by mass or more, 30 parts by mass or more, 35 parts by mass or more, 40 parts by mass or more, or 42 parts by mass or more, and may be 75 parts by mass or less, 72 parts by mass or less, 70 parts by mass or less, or 68 parts by mass or less, per 100 parts by mass of the (A) component. When the content of the (C) component is 10 parts by mass or more per 100 parts by mass of the (A) component, the handleability (e.g., bendability) of the film-like adhesive tends to be improved. When the content of the (C) component is 80 parts by mass or less per 100 parts by mass of the (A) component, the flexibility of the adhesive composition tends to be prevented from becoming too high. This makes it easier to cut the film-like adhesive during wafer dicing, and prevents the generation of burrs. Furthermore, when the amount of the component (C) is 80 parts by mass or less per 100 parts by mass of the component (A), the embeddability of wires or semiconductor chips tends to improve.

[0053] The content of component (C) may be 10 parts by mass or more, 20 parts by mass or more, or 30 parts by mass or more, and may be 80 parts by mass or less, 75 parts by mass or less, 60 parts by mass or less, or 55 parts by mass or less, relative to 100 parts by mass of the total of components (A) and (B). When the content of component (C) is 10 parts by mass or more, relative to 100 parts by mass of the total of components (A) and (B), the handleability (e.g., bendability) of the film-like adhesive tends to be better. When the content of component (C) is 80 parts by mass or less, relative to 100 parts by mass of the total of components (A) and (B), the flexibility of the adhesive composition tends to be more effectively prevented from becoming too high. This tends to make it easier to cut the film-like adhesive during wafer dicing, and to further prevent the generation of burrs.

[0054] <Component (D): Inorganic filler> Examples of inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, boron nitride, crystalline silica, and amorphous silica. These may be used alone or in combination of two or more. From the viewpoint of further improving the thermal conductivity of the resulting film-like adhesive, the inorganic filler may contain aluminum oxide, aluminum nitride, boron nitride, crystalline silica, or amorphous silica. Furthermore, from the viewpoint of adjusting the melt viscosity of the adhesive composition and imparting thixotropy to the adhesive composition, the inorganic filler may be aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, crystalline silica, or amorphous silica, or may be silica (crystalline silica or amorphous silica).

[0055] From the viewpoint of further improving adhesiveness, the average particle size of component (D) may be 0.005 to 0.5 μm or 0.05 to 0.3 μm, where the average particle size refers to a value determined by conversion from the BET specific surface area.

[0056] Component (D) may be surface-treated with a surface treatment agent from the viewpoints of compatibility of the surface with solvents and other components, and adhesive strength. Examples of surface treatment agents include silane coupling agents. Examples of functional groups of silane coupling agents include vinyl groups, (meth)acryloyl groups, epoxy groups, mercapto groups, amino groups, diamino groups, alkoxy groups, and ethoxy groups.

[0057] The content of component (D) may be 25% by mass or more, 28% by mass or more, or 30% by mass or more, based on the total amount of the adhesive composition. When the content of component (D) is 25% by mass or more, based on the total amount of the adhesive composition, the dicing properties of the adhesive layer before curing tend to be improved, and the adhesive strength of the adhesive layer after curing tends to be improved. This ensures sufficient dicing properties, for example, even in relatively thick film-like adhesives for FOD / FOW applications (e.g., 20 μm or more, preferably 30 μm or more). The upper limit of the content of component (D) is not particularly limited, but may be 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total amount of the adhesive composition. When the content of component (D) is 60% by mass or less, based on the total amount of the adhesive composition, a decrease in flowability can be suppressed, and it is possible to prevent the elastic modulus of the film-like adhesive after curing from becoming too high.

[0058] The adhesive composition according to this embodiment is mainly composed of components (A), (B), (C), and (D), and the total content of components (A), (B), (C), and (D) may be 95% by mass or more or 97% by mass or more, and may be 100% by mass or less or 99% by mass or less, based on the total amount of the adhesive composition.

[0059] <Component (E): Curing accelerator> The adhesive composition according to this embodiment may contain (E) a curing accelerator. The curing accelerator is not particularly limited, and a commonly used one may be used. Examples of the (E) component include imidazoles and their derivatives, organic phosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. These may be used alone or in combination of two or more. Among these, from the viewpoint of reactivity, the (E) component may be imidazoles and their derivatives.

[0060] Examples of imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, etc. These may be used alone or in combination of two or more.

[0061] The content of component (E) may be 0.01 to 3 parts by mass or 0.03 to 1 part by mass per 100 parts by mass of the total amount of components (A), (B), and (C). When the content of component (E) is within this range, it tends to be possible to achieve both curability and reliability.

[0062] <Other ingredients> The adhesive composition according to this embodiment may further contain other components such as an antioxidant, a silane coupling agent, a rheology control agent, etc. The content of these components may be 0.01 to 3 parts by mass per 100 parts by mass of the total amount of the components (A), (B), and (C).

[0063] The adhesive composition according to this embodiment may be diluted with a solvent and used as an adhesive varnish. The solvent is not particularly limited as long as it can dissolve components other than component (D). Examples of solvents include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-cymene; aliphatic hydrocarbons such as hexane and heptane; cyclic alkanes such as methylcyclohexane; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; and amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. These solvents may be used alone or in combination. Of these, the solvent may be toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone from the viewpoints of solubility and boiling point.

[0064] The solid component concentration in the adhesive varnish may be 10 to 80 mass % based on the total mass of the adhesive varnish.

[0065] The adhesive varnish can be prepared by mixing and kneading components (A), (B), (C), (D), and a solvent, as well as component (E) and other components, as needed. Mixing and kneading can be performed using an appropriate combination of dispersing machines, such as a conventional mixer, a mortar and pestle, a triple-roll mill, a ball mill, or a bead mill. When mixing component (D), the mixing time can be shortened by premixing component (D) with the low-molecular-weight component and then adding the high-molecular-weight component. After preparing the adhesive varnish, air bubbles in the varnish may be removed by vacuum degassing or the like.

[0066] [Film adhesive] FIG. 1 is a schematic cross-sectional view showing a film-like adhesive according to one embodiment. The film-like adhesive 10 is obtained by forming the above-mentioned adhesive composition into a film. The film-like adhesive 10 may be in a semi-cured (B-stage) state. Such a film-like adhesive 10 can be formed by applying the adhesive composition to a support film. When an adhesive varnish is used, the adhesive varnish can be applied to a support film and the solvent removed by heating and drying to form the film-like adhesive 10.

[0067] The support film is not particularly limited, and examples thereof include films of polytetrafluoroethylene, polyethylene, polypropylene, polymethylpentene, polyethylene terephthalate, polyimide, etc. The thickness of the support film may be, for example, 10 to 200 μm or 20 to 170 μm.

[0068] The adhesive varnish can be applied to the support film by any known method, such as knife coating, roll coating, spray coating, gravure coating, bar coating, curtain coating, etc. The conditions for heat drying are not particularly limited as long as the solvent used is sufficiently volatilized, and may be, for example, at 50 to 200°C for 0.1 to 90 minutes.

[0069] The thickness of the film-like adhesive can be adjusted appropriately depending on the application, and may be 20 to 200 μm, 30 to 200 μm, or 40 to 150 μm, from the viewpoint of sufficiently filling in irregularities in semiconductor chips, wires, wiring circuits on substrates, etc.

[0070] [Adhesive sheet] 2 is a schematic cross-sectional view showing an adhesive sheet according to one embodiment. The adhesive sheet 100 comprises a substrate 20 and the above-described film adhesive 10 provided on the substrate.

[0071] The substrate 20 is not particularly limited, but may be a substrate film, which may be the same as the support film described above.

[0072] The substrate 20 may be a dicing tape. Such an adhesive sheet can be used as an integrated dicing and die bonding adhesive sheet. In this case, the lamination process onto the semiconductor wafer is performed only once, which improves work efficiency.

[0073] Examples of dicing tapes include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. Furthermore, the dicing tape may be subjected to surface treatment such as primer coating, UV treatment, corona discharge treatment, polishing treatment, and etching treatment, as needed. The dicing tape is preferably adhesive. Such a dicing tape may be the above-mentioned plastic film imparted with adhesiveness, or may be the above-mentioned plastic film with an adhesive layer provided on one side thereof.

[0074] The adhesive sheet 100 can be formed by applying an adhesive composition to a substrate film in the same manner as the method for forming the film-like adhesive described above. The method for applying the adhesive composition to the substrate 20 may be the same as the method for applying the adhesive composition to the support film described above.

[0075] The adhesive sheet 100 may be formed using a pre-prepared film-like adhesive. In this case, the adhesive sheet 100 can be formed by laminating under predetermined conditions (for example, room temperature (20°C) or in a heated state) using a roll laminator, vacuum laminator, or the like. The adhesive sheet 100 is preferably formed using a roll laminator in a heated state, as this allows for continuous production and is efficient.

[0076] The thickness of the film adhesive 10 may be 20 to 200 μm, 30 to 200 μm, or 40 to 150 μm from the viewpoint of embedding unevenness in semiconductor chips, wires, wiring circuits of substrates, etc. When the thickness of the film adhesive 10 is 20 μm or more, more sufficient adhesive strength tends to be obtained, and when the thickness of the film adhesive 10 is 200 μm or less, it is economical and can meet the demand for miniaturization of semiconductor devices.

[0077] 3 is a schematic cross-sectional view showing an adhesive sheet according to another embodiment. The adhesive sheet 110 further includes a protective film 30 laminated on the surface of the film-like adhesive 10 opposite the substrate 20. The protective film 30 may be the same as the support film described above. The thickness of the protective film may be, for example, 15 to 200 μm or 70 to 170 μm.

[0078] [Semiconductor Devices] 4 is a schematic cross-sectional view showing a semiconductor device according to one embodiment. The semiconductor device 200 is a semiconductor device in which a first semiconductor element Wa in a first stage is wire-bonded to a substrate 14 via a first wire 88, and a second semiconductor element Waa is pressure-bonded onto the first semiconductor element Wa via a film-like adhesive 10, so that at least a portion of the first wire 88 is embedded in the film-like adhesive 10. The semiconductor device may be a wire-embedded semiconductor device in which at least a portion of the first wire 88 is embedded, or a semiconductor device in which the first wire 88 and the first semiconductor element Wa are embedded. Furthermore, in the semiconductor device 200, the substrate 14 and the second semiconductor element Waa are further electrically connected via a second wire 98, and the second semiconductor element Waa is encapsulated with an encapsulant 42.

[0079] The thickness of the first semiconductor element Wa may be 10 to 170 μm, and the thickness of the second semiconductor element Waa may be 20 to 400 μm. The first semiconductor element Wa embedded inside the film-like adhesive 10 is a controller chip for driving the semiconductor device 200.

[0080] The substrate 14 is made of an organic substrate 90 having circuit patterns 84, 94 formed in two locations on its surface. The first semiconductor element Wa is pressure-bonded onto the circuit pattern 94 via an adhesive 41. The second semiconductor element Waa is pressure-bonded to the substrate 14 via a film-like adhesive 10 so as to cover the circuit pattern 94, the first semiconductor element Wa, and a portion of the circuit pattern 84 to which the first semiconductor element Wa is not pressure-bonded. The film-like adhesive 10 is embedded in uneven steps caused by the circuit patterns 84, 94 on the substrate 14. The second semiconductor element Waa, the circuit pattern 84, and the second wire 98 are then sealed with a resin sealing material 42.

[0081] [Method of manufacturing a semiconductor device] The method for manufacturing a semiconductor device according to this embodiment includes a first wire bonding process for electrically connecting a first semiconductor element to a substrate via a first wire, a laminating process for applying the above-mentioned film adhesive to one side of a second semiconductor element, and a die bonding process for embedding at least a portion of the first wire in the film adhesive by pressing the second semiconductor element with the film adhesive applied via the film adhesive.

[0082] 5 to 9 are schematic cross-sectional views showing a series of steps in a method for manufacturing a semiconductor device according to one embodiment. The semiconductor device 200 according to this embodiment is a semiconductor device in which a first wire 88 and a first semiconductor element Wa are embedded, and is manufactured by the following procedure. First, as shown in FIG. 5, the first semiconductor element Wa having an adhesive 41 is pressure-bonded onto a circuit pattern 94 on the substrate 14, and the circuit pattern 84 on the substrate 14 and the first semiconductor element Wa are electrically bonded via the first wire 88 (first wire bonding step).

[0083] Next, an adhesive sheet 100 is laminated onto one side of a semiconductor wafer (e.g., 100 μm thick, 8 inch size), and the substrate 20 is peeled off, thereby attaching a film adhesive 10 (e.g., 110 μm thick) to one side of the semiconductor wafer. Then, a dicing tape is attached to the film adhesive 10, and the wafer is diced to a predetermined size (e.g., 7.5 mm square), thereby obtaining a second semiconductor element Waa with the film adhesive 10 attached, as shown in FIG. 6 (laminating process).

[0084] The temperature condition for the lamination step may be 50 to 100°C or 60 to 80°C. When the temperature for the lamination step is 50°C or higher, good adhesion to the semiconductor wafer can be obtained. When the temperature for the lamination step is 100°C or lower, excessive flow of the film-like adhesive 10 during the lamination step is suppressed, thereby preventing changes in thickness and the like.

[0085] Examples of dicing methods include blade dicing using a rotary blade, and a method of cutting the film adhesive or both the wafer and the film adhesive with a laser.

[0086] The second semiconductor element Waa with the film-like adhesive 10 attached thereto is then pressure-bonded to the substrate 14 to which the first semiconductor element Wa is bonded via the first wire 88. Specifically, as shown in FIG. 7, the second semiconductor element Waa with the film-like adhesive 10 attached thereto is placed so that the first wire 88 and the first semiconductor element Wa are covered by the film-like adhesive 10. Then, as shown in FIG. 8, the second semiconductor element Waa is pressure-bonded to the substrate 14 to fix the second semiconductor element Waa to the substrate 14 (die-bonding process). In the die-bonding process, the film-like adhesive 10 is preferably pressure-bonded for 0.5 to 3.0 seconds under conditions of 80 to 180°C and 0.01 to 0.50 MPa. After the die-bonding process, the film-like adhesive 10 is pressurized and heated for 5 minutes or more under conditions of 60 to 175°C and 0.3 to 0.7 MPa.

[0087] 9, the substrate 14 and the second semiconductor element Waa are electrically connected via second wires 98 (second wire bonding step), and then the circuit pattern 84, the second wires 98, and the second semiconductor element Waa are sealed with the sealing material 42. Through these steps, the semiconductor device 200 can be manufactured.

[0088] As another embodiment, the semiconductor device may be a wire-buried type semiconductor device in which at least a portion of the first wire 88 is buried. [Example]

[0089] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0090] (Examples 1 to 8 and Comparative Examples 1 to 4) <Preparation of adhesive sheet> The components shown below were mixed in the blending ratios (parts by mass) shown in Tables 1 and 2, and a varnish of an adhesive composition with a solids content of 40% by mass was prepared using cyclohexanone as a solvent. The resulting varnish was then filtered through a 100-mesh filter and vacuum degassed. The vacuum degassed varnish was applied to a 38-μm-thick polyethylene terephthalate (PET) film that had been subjected to a release treatment as a substrate film. The applied varnish was heated and dried in two stages: at 90°C for 5 minutes and then at 140°C for 5 minutes. In this way, an adhesive sheet was obtained on the substrate film, comprising a 110-μm-thick film-like adhesive in a semi-cured (B-stage) state.

[0091] The components in Tables 1 and 2 are as follows:

[0092] (A) Thermosetting resin A-1: Epoxy resin having a dicyclopentadiene structure, manufactured by DIC Corporation, product name: HP-7200L, epoxy equivalent: 250-280g / eq A-2: Epoxy resin with a dicyclopentadiene structure, manufactured by Nippon Kayaku Co., Ltd., product name: XD-1000, epoxy equivalent: 254 g / eq A-3: Alicyclic epoxy resin, manufactured by Daicel Corporation, product name: EHPE3150, epoxy equivalent: 170-190g / eq A-4: Multifunctional aromatic epoxy resin, manufactured by Printec Co., Ltd., product name: VG3101L, epoxy equivalent: 210g / eq A-5: Cresol novolac epoxy resin, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., product name: YDCN-700-10, epoxy equivalent: 209 g / eq A-6: Bisphenol F epoxy resin (liquid at 25°C), manufactured by DIC Corporation, product name: EXA-830CRP, epoxy equivalent: 159g / eq (B) Hardener (B-1) Phenol resin having an alicyclic ring B-1-1: Phenolic resin having a dicyclopentadiene structure represented by general formula (1a), manufactured by JFE Chemical Corporation, trade name: J-DPP-85, hydroxyl group equivalent: 164 to 167 g / eq, softening point: 85 to 89°C B-1-2: Phenolic resin having a dicyclopentadiene structure represented by general formula (1a), manufactured by JFE Chemical Corporation, trade name: J-DPP-115, hydroxyl group equivalent: 177 to 181 g / eq, softening point: 107 to 116°C (B-2) Phenol resin without alicyclic ring B-2-1: Bisphenol A novolac phenolic resin, manufactured by DIC Corporation, product name: LF-4871, hydroxyl equivalent: 118 g / eq B-2-2: Phenylaralkyl phenolic resin, manufactured by Mitsui Chemicals, Inc., product name: XLC-LL, hydroxyl equivalent: 175 g / eq B-2-3: Phenylaralkyl phenolic resin, manufactured by Air Water Inc., product name: HE100C-30, hydroxyl equivalent: 170 g / eq (C) Elastomer C-1: Epoxy group-containing acrylic resin (acrylic rubber), manufactured by Nagase ChemteX Corporation, product name: SG-P3 solvent-modified product, weight-average molecular weight: 800,000, glycidyl functional group monomer ratio: 3%, Tg: -7°C C-2: Acrylic resin (acrylic rubber), manufactured by Nagase ChemteX Corporation, product name: SG-70L, weight average molecular weight: 900,000, acid value: 5 mg KOH / g, Tg: -13°C C-3: Carboxyl group-containing acrylic resin (acrylic rubber), manufactured by Nagase ChemteX Corporation, product name: SG-708-6, weight average molecular weight: 700,000, acid value: 9 mg KOH / g, Tg: 4°C (D) Inorganic filler D-1: Silica filler dispersion, fused silica, manufactured by Admatechs Co., Ltd., product name: SC2050-HLG, average particle size: 0.50 μm (E) Curing accelerator E-1: 1-cyanoethyl-2-phenylimidazole, manufactured by Shikoku Chemicals Corporation, trade name: Curesol 2PZ-CN

[0093] <Evaluation of various physical properties> The resulting adhesive sheet was evaluated for embeddability and bleeding amount.

[0094] [Embeddability evaluation] The embeddability of the adhesive sheet was evaluated by preparing the following evaluation samples. The base film of the film-like adhesive (110 μm thick) obtained above was peeled off and attached to dicing tape to prepare a dicing-die bonding integrated adhesive sheet. Next, a 100 μm thick semiconductor wafer (8 inches) was prepared and attached to the adhesive side of a dicing-die bonding integrated adhesive sheet by heating to 70°C. This semiconductor wafer was then diced into 7.5 mm squares to obtain semiconductor chip A. Next, a 50 μm thick semiconductor wafer (8 inches) and another dicing-die bonding integrated adhesive sheet (Hitachi Chemical Co., Ltd., product name: HR9004-10) (thickness: 10 μm) were prepared, and the semiconductor wafer was attached to the adhesive side of the dicing-die bonding integrated adhesive sheet by heating to 70°C. This semiconductor wafer was then diced into 4.5 mm squares to obtain semiconductor chip B with die bonding film. Next, a 260 μm thick evaluation substrate coated with solder resist (Taiyo Nippon Sanso Corporation, product name: AUS308) was prepared. The evaluation substrate was then pressed at 120°C, 0.20 MPa, and 2 seconds so that the die bonding film of semiconductor chip B and the solder resist of the evaluation substrate were in contact. The semiconductor chip A was then pressed at 120°C, 0.20 MPa, and 1.5 seconds so that the film adhesive of semiconductor chip A and the semiconductor wafer of semiconductor chip B were in contact, obtaining an evaluation sample. During this process, semiconductor chip B, which had been pressed first, was aligned with the center of semiconductor chip A. The evaluation sample thus obtained was observed for the presence or absence of voids using an ultrasound digital imaging diagnostic device (Insight Corporation, probe: 75 MHz). If voids were observed, the percentage of void area per unit area was calculated, and these analysis results were evaluated as fillability. The evaluation criteria were as follows. The results are shown in Tables 1 and 2. A: No voids were observed. B: Voids were observed, but the proportion was less than 5% by area. C: Voids were observed, and the proportion of voids was 5% or more by area.

[0095] [Bleed amount evaluation] The samples that received an "A" or "B" rating in the embeddability evaluation were evaluated for the amount of bleeding. Evaluation samples for the amount of bleeding were prepared in the same manner as the evaluation samples prepared in the embeddability evaluation. Using a microscope, the amount of film adhesive protruding from the center of each of the four sides of the evaluation sample was measured, and the maximum value was taken as the amount of bleeding. The results are shown in Tables 1 and 2.

[0096] [Table 1]

[0097] [Table 2]

[0098] As shown in Tables 1 and 2, Examples 1 to 6, which contained a phenolic resin having an alicyclic ring, were able to suppress bleeding while maintaining good embeddability, compared to Comparative Examples 1 to 4, which did not contain such a phenolic resin. These results confirmed that the adhesive composition according to the present invention is capable of suppressing bleeding while maintaining good embeddability during thermocompression bonding. [Industrial Applicability]

[0099] As the above results show, the adhesive composition of the present invention is excellent in that it has good embeddability during thermocompression bonding and can suppress bleeding, and therefore a film adhesive formed from the adhesive composition in the form of a film can be useful as a chip-embedded film adhesive (FOD) or a wire-embedded film adhesive (FOW) . [Explanation of symbols]

[0100] 10...film-like adhesive, 14...substrate, 20...base material, 30...protective film, 41...adhesive, 42...sealant, 84, 94...circuit pattern, 88...first wire, 90...organic substrate, 98...second wire, 100, 110...adhesive sheet, 200...semiconductor device, Wa...first semiconductor element, Waa...second semiconductor element.

Claims

[Claim 1] The composition contains a thermosetting resin, a curing agent, an elastomer, and an inorganic filler, the curing agent contains a phenolic resin having an alicyclic ring, The adhesive composition has a content of the elastomer of 10 to 80 parts by mass relative to 100 parts by mass of the thermosetting resin.

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