JP7513015B2 - Adhesive composition, film-like adhesive, adhesive sheet, and method for manufacturing semiconductor device - Google Patents

Description

The present invention relates to an adhesive composition, a film-like adhesive, an adhesive sheet, and a method for manufacturing a semiconductor device.

Traditionally, silver paste has been mainly used to bond semiconductor chips to support members on which they are mounted. However, with the recent trend toward smaller and more integrated semiconductor chips, there is a demand for smaller and finer support members to be used. On the other hand, when silver paste is used, problems such as malfunctions during wire bonding due to the overflow of paste or tilt of the semiconductor chip, difficulty in controlling film thickness, and the occurrence of voids can occur.

For this reason, in recent years, film-like 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-like adhesive laminated on the dicing tape, a semiconductor chip with a film-like adhesive can be obtained by attaching the film-like adhesive to the back surface of a semiconductor wafer and dicing the semiconductor wafer into individual pieces. The obtained semiconductor chip with a film-like adhesive can be attached to a support member via the film-like adhesive and bonded by thermocompression.

JP 2007-053240 A

However, as the size of semiconductor chips becomes smaller, the force applied per unit area during thermocompression bonding increases, which can lead to a phenomenon known as bleeding, in which the film-like adhesive protrudes from the semiconductor chip.

Furthermore, when the film adhesive is used as a wire-embedded film adhesive (FOW, Film Over Wire) or a semiconductor chip-embedded film adhesive (FOD, Film Over Die), high fluidity is required during thermocompression bonding in order to improve embeddability. This tends to further increase the frequency and amount of bleeding. In some cases, bleeding may occur on the top surface of the semiconductor chip, which may lead to electrical defects or wire bonding defects.

The present invention has been made in consideration of these circumstances, and its main objective is to provide an adhesive composition that has good embeddability during thermocompression bonding while suppressing bleeding.

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 has good embeddability during thermocompression bonding and can suppress bleeding.

The thermosetting resin may be an epoxy resin. The epoxy resin may include a bisphenol F type epoxy resin.

The elastomer may be an acrylic resin.

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

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

The adhesive composition may further contain a curing accelerator.

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

The present invention may further relate to the 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 the manufacture of an adhesive, which is used to press a second semiconductor element and embed at least a portion of the first wire in a semiconductor device in which a first semiconductor element is wire-bonded to a substrate via a first wire and a second semiconductor element is press-bonded onto the first semiconductor element.

Another aspect of the present invention provides a film-like adhesive formed by forming the above-mentioned adhesive composition into a film.

Another aspect of the present invention provides an adhesive sheet comprising a substrate and the above-mentioned film-like adhesive provided on the substrate.

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

The adhesive sheet may further include a protective film laminated on the side of the film-like adhesive opposite the substrate.

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 onto a substrate via a first wire, a lamination 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 to which the film-like adhesive has been applied via the film-like adhesive.

The semiconductor device may be a wire-embedded type 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 type semiconductor device in which the first wire and the first semiconductor chip are embedded in the adhesive film.

According to the present invention, an adhesive composition is provided that has good embedding properties during thermocompression bonding and can suppress bleeding. Therefore, a film-like adhesive obtained by forming the adhesive composition into a film can be useful as a film-like adhesive for embedding semiconductor chips (FOD) or a film-like adhesive for embedding wires (FOW). In addition, according to the present invention, a method for manufacturing an adhesive sheet and a semiconductor device using such a film-like adhesive is provided.

FIG. 2 is a schematic cross-sectional view showing a film-like adhesive according to one embodiment. FIG. 1 is a schematic cross-sectional view showing an adhesive sheet according to an embodiment. FIG. 4 is a schematic cross-sectional view showing an adhesive sheet according to another embodiment. 1 is a schematic cross-sectional view showing a semiconductor device according to an embodiment; 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. 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. 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. 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. 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.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiment.

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

[Adhesive composition]
The adhesive composition according to the present 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 be in a semi-cured (B stage) state and then in a completely cured (C stage) state after a curing treatment.

<Component (A): Thermosetting Resin>
From the viewpoint of adhesiveness, the (A) component may be an epoxy resin. The epoxy resin may be any compound having an epoxy group in the molecule, and may be used without any particular limitation. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, stilbene type epoxy resin, triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, triphenol methane type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, and epoxy resin 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 type epoxy resin. When the epoxy resin contains bisphenol F type epoxy resin, the embeddability tends to be improved. 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).

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 in such a range, good reactivity and flowability tend to be obtained. When component (A) contains bisphenol F type epoxy resin, the epoxy equivalent of the bisphenol F type epoxy resin may be less than 180 g/eq, and may be 170 g/eq or 160 g/eq or less from the viewpoint of embeddability. The epoxy equivalent of the bisphenol F type epoxy resin may be 90 g/eq or more, 100 g/eq or more, or 120 g/eq or more.

<Component (B): Curing Agent>
The component (B) contains a phenol resin (B-1) having an alicyclic ring.

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.

The (B-1) component may be, for example, a phenolic resin represented by the following general formula (1):

In formula (1), E represents an alicyclic ring, G represents a single bond or an alkylene group, and each ^R1 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.

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 is 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, an ethylene group, a propylene group, a butylene group, or a pentylene group. G is preferably a single bond. The monovalent hydrocarbon group in R ¹ 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. R ¹ is preferably a hydrogen atom.

The phenolic resin represented by general formula (1) may be a phenolic resin represented by the following general formula (1a):

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

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).

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 in such a range, good reactivity and flowability tend to be obtained.

The content of the (B-1) component 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 the (B-1) component is 5% by mass or more, based on the total amount of the adhesive composition, there is a tendency for bleeding to be well suppressed while having better embeddability during thermocompression bonding. The content of the (B-1) component 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.

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 novolac-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and/or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene with compounds having aldehyde groups such as formaldehyde under an acidic catalyst, allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenol novolac, and phenol aralkyl resins synthesized from phenols such as phenol and/or naphthols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl, naphthol aralkyl resins, biphenyl aralkyl-type phenolic resins, and phenyl aralkyl-type phenolic resins. These may be used alone or in combination of two or more.

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 in such a range, good reactivity and flowability tend to be obtained.

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

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, it is possible to prevent the viscosity from becoming too high, and more sufficient fluidity can be obtained.

The total content of the (A) and (B) components may be 30 to 70% by mass based on the total amount of the adhesive composition. The total content of the (A) and (B) components 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 the (A) and (B) components is 30% by mass or more based on the total amount of the adhesive composition, the adhesiveness tends to be improved. When the total content of the (A) and (B) components 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.

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

Examples of component (C) include acrylic resin, polyester resin, polyamide resin, polyimide resin, silicone resin, butadiene resin, acrylonitrile resin, and modified versions of these.

The (C) component may contain an acrylic resin from the viewpoint of solubility in a solvent and fluidity. Here, the acrylic resin means 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 an acrylonitrile.

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 makes it possible to prevent 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 fill voids sufficiently when the film-like adhesive is attached to the wafer. In addition, it makes it possible to prevent chipping during dicing due to a decrease in wafer adhesion. Here, the glass transition temperature (Tg) means a value measured using a TMA tester (manufactured by TA Instruments, TMA400Q).

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 in this range, the film formability, strength in the film state, flexibility, tackiness, etc. can be appropriately controlled, and the reflowability and embeddability can be improved. Here, Mw means a value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

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

The content of the (C) component is 10 to 80 parts by mass relative to 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 relative to 100 parts by mass of the (A) component, 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. When the content of the (C) component is 10 parts by mass or more relative to 100 parts by mass of the (A) component, the handleability (e.g., bendability, etc.) of the film-like adhesive tends to be good. When the content of the (C) component is 80 parts by mass or less relative to 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 makes it possible to prevent burrs from occurring. Furthermore, when the content 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 be improved.

The content of the (C) component may be 10 parts by mass or more, 20 parts by mass or more, or 30 parts by mass or more, and 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 amount of the (A) component and the (B) component. When the content of the (C) component is 10 parts by mass or more relative to 100 parts by mass of the total amount of the (A) component and the (B) component, the handling property (e.g., bending property, etc.) of the film-like adhesive tends to be better. When the content of the (C) component is 80 parts by mass or less relative to 100 parts by mass of the total amount of the (A) component and the (B) 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 tends to further prevent the occurrence of burrs.

<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 whisker, 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 obtained film-like adhesive, the inorganic filler may contain aluminum oxide, aluminum nitride, boron nitride, crystalline silica, or amorphous silica. In addition, from the viewpoint of adjusting the melt viscosity of the adhesive composition and from the viewpoint of 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).

The average particle size of component (D) may be 0.005 to 0.5 μm or 0.05 to 0.3 μm from the viewpoint of further improving adhesion. Here, the average particle size means the value calculated by converting from the BET specific surface area.

The (D) component may be surface-treated with a surface treatment agent from the viewpoint of compatibility of the surface with the solvent and other components, and adhesive strength. Examples of the surface treatment agent include silane coupling agents. Examples of functional groups of the silane coupling agent include vinyl groups, (meth)acryloyl groups, epoxy groups, mercapto groups, amino groups, diamino groups, alkoxy groups, and ethoxy groups.

The content of the (D) component 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 the (D) component is 25% by mass or more, based on the total amount of the adhesive composition, the dicing property of the adhesive layer before curing tends to improve, and the adhesive strength of the adhesive layer after curing tends to improve. This ensures sufficient dicing property, for example, in a relatively thick film-like adhesive for FOD/FOW applications (e.g., 20 μm or more, preferably 30 μm or more). The upper limit of the content of the (D) component 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 the (D) component is 60% by mass or less, based on the total amount of the adhesive composition, it is possible to suppress a decrease in fluidity and prevent the elastic modulus of the film-like adhesive after curing from becoming too high.

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.

<Component (E): Curing Accelerator>
The adhesive composition according to the present embodiment may contain a curing accelerator (E). 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, the (E) component may be imidazoles and their derivatives from the viewpoint of reactivity.

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.

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 such a range, it tends to be possible to achieve both curability and reliability.

<Other ingredients>
The adhesive composition according to the present embodiment may further contain, as other components, 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 relative to 100 parts by mass of the total amount of the components (A), (B), and (C).

The adhesive composition according to the present embodiment may be used as an adhesive varnish diluted with a solvent. The solvent is not particularly limited as long as it can dissolve components other than component (D). Examples of the solvent 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 may be used alone or in combination of two or more. Among these, the solvent may be toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone from the viewpoints of solubility and boiling point.

The solid component concentration in the adhesive varnish may be 10 to 80% by weight, based on the total weight of the adhesive varnish.

The adhesive varnish can be prepared by mixing and kneading the (A) components, (B) components, (C) components, (D) components, and the solvent, and, if necessary, the (E) component and other components. Mixing and kneading can be performed using an appropriate combination of dispersing machines such as a normal stirrer, a grinding machine, a triple roll, a ball mill, and a bead mill. When mixing the (D) component, the mixing time can be shortened by mixing the (D) component with the low molecular weight component in advance and then blending the high molecular weight component. In addition, after preparing the adhesive varnish, air bubbles in the varnish can be removed by vacuum degassing or the like.

[Film-type adhesive]
FIG. 1 is a schematic cross-sectional view showing a film-like adhesive according to one embodiment. The film-like adhesive 10 is formed 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 can be removed by heating and drying to form the film-like adhesive 10.

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.

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, but may be, for example, 50 to 200°C for 0.1 to 90 minutes.

The thickness of the film-like adhesive can be adjusted appropriately depending on the application. The thickness of the film-like adhesive 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 of substrates, etc.

[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-mentioned film-like adhesive 10 provided on the substrate.

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

The substrate 20 may be a dicing tape. Such an adhesive sheet can be used as a dicing die bonding integrated adhesive sheet. In this case, the lamination process to the semiconductor wafer is performed only once, which can improve the efficiency of the work.

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

The adhesive sheet 100 can be formed by applying the 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 can be the same as the method for applying the adhesive composition to the support film described above.

The adhesive sheet 100 may be formed using a film-like adhesive prepared in advance. In this case, the adhesive sheet 100 can be formed by laminating under predetermined conditions (for example, at 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, since it can be produced continuously and efficiently.

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

Figure 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 similar to the support film described above. The thickness of the protective film may be, for example, 15 to 200 μm or 70 to 170 μm.

[Semiconductor device]
4 is a schematic cross-sectional view showing a semiconductor device according to an 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 part of the first wire 88 is embedded in the film-like adhesive 10. The semiconductor device may be a wire-embedded type semiconductor device in which at least a part 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. 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 sealed with a sealing material 42.

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.

The substrate 14 is made of an organic substrate 90 on whose surface the circuit patterns 84, 94 are formed in two places each. 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 that the circuit pattern 94, the first semiconductor element Wa, and a part of the circuit pattern 84 to which the first semiconductor element Wa is not pressure-bonded are covered. The film-like adhesive 10 is embedded in the 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 sealed with a resin sealing material 42.

[Method of Manufacturing Semiconductor Device]
The manufacturing method of the semiconductor device according to this embodiment includes a first wire bonding process for electrically connecting a first semiconductor element onto a substrate via a first wire, a lamination 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 into the film-like adhesive by pressing the second semiconductor element to which the film-like adhesive has been applied via the film-like adhesive.

Figures 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 Figure 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 together via the first wire 88 (first wire bonding process).

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 to attach a film-like adhesive 10 (e.g., 110 μm thick) to one side of the semiconductor wafer. Then, a dicing tape is attached to the film-like adhesive 10, and the wafer is diced to a predetermined size (e.g., 7.5 mm square) to obtain a second semiconductor element Waa with the film-like adhesive 10 attached, as shown in FIG. 6 (lamination process).

The temperature conditions for the lamination process may be 50 to 100°C or 60 to 80°C. If the temperature for the lamination process is 50°C or higher, good adhesion with the semiconductor wafer can be obtained. If the temperature for the lamination process is 100°C or lower, excessive flow of the film-like adhesive 10 during the lamination process is suppressed, thereby preventing changes in thickness, etc.

Dicing methods include, for example, blade dicing using a rotating blade, and a method in which the film adhesive or both the wafer and the film adhesive are cut using a laser.

Then, the second semiconductor element Waa to which the film-like adhesive 10 is attached is pressed onto 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 to which the film-like adhesive 10 is attached is placed so that the first wire 88 and the first semiconductor element Waa are covered by the film-like adhesive 10, and then, as shown in FIG. 8, the second semiconductor element Waa is pressed onto the substrate 14 to fix the second semiconductor element Waa to the substrate 14 (die-bonding process). In the die-bonding process, it is preferable to press the film-like adhesive 10 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.

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

In another embodiment, the semiconductor device may be a wire-embedded type semiconductor device in which at least a portion of the first wire 88 is embedded.

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

(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 solid content of 40% by mass was prepared using cyclohexanone as a solvent. Next, the obtained varnish was filtered through a 100-mesh filter and vacuum degassed. The varnish after vacuum degassing was applied to a polyethylene terephthalate (PET) film with a thickness of 38 μm 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 having a film-like adhesive with a thickness of 110 μm in a semi-cured (B-stage) state was obtained on the substrate film.

The components in Tables 1 and 2 are as follows:

(A) Thermosetting Resin A-1: Epoxy resin having a dicyclopentadiene structure, manufactured by DIC Corporation, product name: HP-7200L, epoxy equivalent: 250 to 280 g/eq
A-2: Epoxy resin having 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 to 190 g/eq
A-4: Polyfunctional aromatic epoxy resin, manufactured by Printec Co., Ltd., product name: VG3101L, epoxy equivalent: 210 g/eq
A-5: Cresol novolac type epoxy resin, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., product name: YDCN-700-10, epoxy equivalent: 209 g/eq
A-6: Bisphenol F type epoxy resin (liquid at 25°C), manufactured by DIC Corporation, product name: EXA-830CRP, epoxy equivalent: 159g/eq
(B) Curing Agent (B-1) Phenol Resin Having an Alicyclic Ring B-1-1: Phenol resin having a dicyclopentadiene structure represented by general formula (1a), manufactured by JFE Chemical Corporation, trade name: J-DPP-85, hydroxyl equivalent: 164 to 167 g/eq, softening point 85 to 89° C.
B-1-2: Phenol resin having a dicyclopentadiene structure represented by general formula (1a), manufactured by JFE Chemical Corporation, trade name: J-DPP-115, hydroxyl equivalent: 177 to 181 g/eq, softening point: 107 to 116° C.
(B-2) Phenol resin not having an alicyclic ring B-2-1: Bisphenol A novolac type phenol resin, manufactured by DIC Corporation, product name: LF-4871, hydroxyl group equivalent: 118 g/eq
B-2-2: Phenylaralkyl type phenolic resin, manufactured by Mitsui Chemicals, Inc., product name: XLC-LL, hydroxyl group equivalent: 175 g/eq
B-2-3: Phenylaralkyl type phenolic resin, manufactured by Air Water Inc., product name: HE100C-30, hydroxyl group 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 mgKOH/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 mgKOH/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 Chemical Industry Co., Ltd., trade name: Curesol 2PZ-CN

<Evaluation of various physical properties>
The obtained adhesive sheet was evaluated for embedding property and bleeding amount.

[Evaluation of embeddability]
The embeddability of the adhesive sheet was evaluated by preparing the following evaluation samples. The base film of the film-like adhesive (thickness 110 μm) obtained above was peeled off and attached to a dicing tape to prepare a dicing die bonding integrated adhesive sheet. Next, a semiconductor wafer (8 inches) having a thickness of 100 μm was prepared, and this was heated to 70 ° C. and attached to the adhesive side of the dicing die bonding integrated adhesive sheet. Then, the semiconductor wafer was diced into 7.5 mm squares to obtain a semiconductor chip A. Next, a semiconductor wafer (8 inches) having a thickness of 50 μm and a dicing die bonding integrated adhesive sheet (Hitachi Chemical Co., Ltd., product name: HR9004-10) (thickness 10 μm) different from the above were prepared, and the semiconductor wafer was heated to 70 ° C. and attached to the adhesive side of the dicing die bonding integrated adhesive sheet. Then, the semiconductor wafer was diced into 4.5 mm squares to obtain a semiconductor chip B with a die bonding film. Next, a 260 μm-thick evaluation substrate coated with solder resist (Taiyo Nippon Sanso Co., Ltd., product name: AUS308) was prepared, and the die bonding film of the semiconductor chip B and the solder resist of the evaluation substrate were pressed at 120° C., 0.20 MPa, and 2 seconds so that they were in contact with each other. Then, the film-like adhesive of the semiconductor chip A and the semiconductor wafer of the semiconductor chip B were pressed at 120° C., 0.20 MPa, and 1.5 seconds so that they were in contact with each other, to obtain an evaluation sample. At this time, the semiconductor chip B, which had been pressed earlier, was aligned so that it was in the center of the semiconductor chip A. The evaluation sample thus obtained was observed with an ultrasonic digital imaging diagnostic device (manufactured by Insight Co., Ltd., probe: 75 MHz) to see whether or not voids were observed, and if voids were observed, the ratio of the area of the voids per unit area was calculated, and these analysis results were evaluated as embeddability. The evaluation criteria are 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.

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

As shown in Tables 1 and 2, Examples 1 to 6, which contain a phenolic resin having an alicyclic ring, were able to suppress bleeding while maintaining good embeddability, compared to Comparative Examples 1 to 4, which do 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.

As the above results show, the adhesive composition of the present invention is excellent in terms of its good embeddability during thermocompression bonding and its ability to suppress bleeding, and therefore a film adhesive obtained by forming the adhesive composition into a film can be useful as a chip-embedded film adhesive (FOD, film over die) or a wire-embedded film adhesive (FOW, film over wire).

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 (9)

The composition contains a thermosetting resin, a curing agent, an elastomer, and an inorganic filler,
the thermosetting resin is an epoxy resin,
The epoxy resin comprises a bisphenol F type epoxy resin,
the curing agent comprises a phenolic resin having an alicyclic ring,
The content of the elastomer is 10 to 80 parts by mass relative to 100 parts by mass of the thermosetting resin,
The content of the inorganic filler is 25% by mass or more based on the total amount of the adhesive composition,
a total content of the thermosetting resin, the curing agent, the elastomer, and the inorganic filler is 95 mass% or more based on the total amount of the adhesive composition;
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, the adhesive composition is used for pressure-bonding the second semiconductor element and embedding at least a portion of the first wire or the first wire and the first semiconductor element . The adhesive composition according to claim 1, wherein the elastomer is an acrylic resin. The adhesive composition according to claim 1 or 2, wherein the inorganic filler is silica. The adhesive composition according to any one of claims 1 to 3, further comprising a curing accelerator. A film-like adhesive formed by forming the adhesive composition according to any one of claims 1 to 4 into a film. A substrate;
The film-like adhesive according to claim 5 provided on the substrate;
An adhesive sheet comprising: The adhesive sheet according to claim 6, wherein the substrate is a dicing tape. The adhesive sheet according to claim 6 or 7, further comprising a protective film laminated on the surface of the film-like adhesive opposite the substrate. a wire bonding process for electrically connecting a first semiconductor element onto a substrate via a first wire;
a lamination step of applying the film-like adhesive according to claim 5 to one surface of a second semiconductor element;
a die bonding process in which the second semiconductor element to which the film-like adhesive is attached is pressure-bonded via the film-like adhesive, thereby embedding at least a portion of the first wire in the film-like adhesive;
A manufacturing method of a semiconductor device comprising:

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