阅读说明：本技术 热固性片材及切割芯片接合薄膜 (Thermosetting sheet and dicing die-bonding film ) 是由 市川智昭 三田亮太 于 2020-10-30 设计创作，主要内容包括：本发明涉及热固性片材及切割芯片接合薄膜。本发明的热固性片材包含热固性树脂和无机颗粒作为必要成分且包含挥发成分作为任意成分,固化后的前述热固性片材中的前述无机颗粒的颗粒填充率P-2相对于固化前的前述热固性片材中的前述无机颗粒的颗粒填充率P-1之比P-2/P-1≥1.3。(The present invention relates to a thermosetting sheet and a dicing die-bonding film. The thermosetting sheet of the present invention contains a thermosetting resin and inorganic particles as essential components and a volatile component as an optional component, and the thermosetting sheet after curing is one of the aboveParticle filling ratio P of the aforementioned inorganic particles 2 A particle filling rate P with respect to the aforementioned inorganic particles in the aforementioned thermosetting sheet before curing 1 Ratio P 2 /P 1 ≥1.3。)

1. A thermosetting sheet material is provided which comprises a base material,

which contains a thermosetting resin and inorganic particles as essential components and contains a volatile component as an arbitrary component,

a particle filling rate P of the inorganic particles in the cured thermosetting sheet₂A particle filling rate P relative to the inorganic particles in the thermosetting sheet before curing₁Ratio P₂/P₁≥1.3。

2. The thermosetting sheet material according to claim 1,

which contains the volatile components as essential components,

the volatile component contains 1 or more hydroxyl groups and has a boiling point of 250 ℃ or higher.

3. The thermosetting sheet according to claim 1 or 2,

the volatile component is terpene compound.

4. The thermosetting sheet according to claim 1 or 2,

the inorganic particles are sintered metal particles.

5. The thermosetting sheet according to claim 1 or 2,

a particle filling rate P of the inorganic particles in the cured thermosetting sheet₂40% by volume or more.

6. A dicing die-bonding film comprising:

a base material layer,

A dicing tape having a pressure-sensitive adhesive layer laminated on the base material layer, and

a thermosetting sheet laminated on the adhesive layer of the dicing tape,

the thermosetting sheet according to any one of claims 1 to 5.

Technical Field

The present invention relates to a thermosetting sheet and a dicing die-bonding film.

Background

Conventionally, as a method (die bonding method) for bonding a semiconductor element to an adherend such as a metal lead frame in the manufacture of a semiconductor device, a method using a thermosetting sheet has been known (for example, patent document 1).

Patent document 1 discloses a thermosetting sheet containing conductive particles and a thermosetting resin as a thermosetting sheet.

In this method, a thermosetting sheet is temporarily bonded to an adherend such as a metal lead frame at a predetermined temperature (for example, 70 ℃) in a state where one surface is provided with a semiconductor element, and then thermally cured at a temperature higher than this (for example, 200 ℃) to bond to the adherend.

However, when a power semiconductor element is used in a semiconductor device, the power semiconductor element is used under a large power of several MVA or more, and therefore a large amount of heat is generated.

Therefore, when the thermosetting sheet described above is used for a power semiconductor element, the thermosetting sheet bonded to an adherend, that is, the cured thermosetting sheet preferably has high heat dissipation properties.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2019-21813

Disclosure of Invention

Problems to be solved by the invention

The above-described problem of heat generation similarly occurs in the case of using a semiconductor element other than the power semiconductor element.

However, it is still difficult to say that sufficient studies have been made to improve the heat dissipation property of the cured thermosetting sheet.

Accordingly, an object of the present invention is to provide a thermosetting sheet having high heat dissipation properties after curing, and a dicing die-bonding film provided with the thermosetting sheet.

Means for solving the problems

The thermosetting sheet of the present invention is as follows:

containing a thermosetting resin and inorganic particles as essential components and a volatile component as an arbitrary component,

a particle filling ratio P of the inorganic particles in the cured thermosetting sheet₂A particle filling rate P with respect to the aforementioned inorganic particles in the aforementioned thermosetting sheet before curing₁Ratio P₂/P₁≥1.3。

In the aforementioned thermosetting sheet, it is preferable that,

which contains the above-mentioned volatile components as essential components,

the volatile component contains 1 or more hydroxyl groups and has a boiling point of 250 ℃ or higher.

In the aforementioned thermosetting sheet, it is preferable that,

the volatile component is terpene compound.

In the aforementioned thermosetting sheet, it is preferable that,

the inorganic particles are sintered metal particles.

In the aforementioned thermosetting sheet, it is preferable that,

a particle filling ratio P of the inorganic particles in the cured thermosetting sheet₂40% by volume or more.

The dicing die-bonding film of the present invention comprises:

a base material layer,

A dicing tape having a pressure-sensitive adhesive layer laminated on the base material layer, and

a thermosetting sheet laminated on the adhesive layer of the dicing tape,

the thermosetting sheet is any of the thermosetting sheets described above.

Description of the reference numerals

1 base material layer

2 adhesive layer

3 thermosetting sheet

10 cutting belt

20-dicing die-bonding film

Drawings

Fig. 1 is a cross-sectional view showing a structure of a dicing die-bonding film according to an embodiment of the present invention.

Detailed Description

Hereinafter, one embodiment of the present invention will be described.

[ thermosetting sheet ]

The thermosetting sheet of the present embodiment contains a thermosetting resin and inorganic particles as essential components and contains a volatile component as an arbitrary component.

Examples of the thermosetting resin include: epoxy resins, phenol resins, amino resins, unsaturated polyester resins, polyurethane resins, silicone resins, thermosetting polyimide resins, and the like. Among these, epoxy resins are preferably used.

Examples of the epoxy resin include: bisphenol A type, bisphenol F type, bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, phenol novolac type, o-cresol novolac type, trishydroxyphenylmethane type, tetraphenylethane (Tetraphenylol ethane) type, hydantoin type, triglycidyl isocyanurate type, and glycidyl amine type epoxy resins.

Examples of the phenolic resin as a curing agent for the epoxy resin include: novolak-type phenol resins, resol-type phenol resins, and polyoxystyrenes such as polyoxystyrenes.

Further, as the thermosetting resin, a thermoplastic resin having a thermosetting functional group may also be used. Examples of the thermoplastic resin having a thermosetting functional group include an acrylic resin having a thermosetting functional group. Examples of the acrylic resin in the thermosetting functional group-containing acrylic resin include resins containing a monomer unit derived from a (meth) acrylate ester.

In the thermoplastic resin having a thermosetting functional group, a curing agent is selected according to the kind of the thermosetting functional group.

The thermosetting sheet of the present embodiment may contain a thermosetting catalyst in order to sufficiently progress the curing reaction of the resin component or to increase the curing reaction rate. Examples of the heat curing catalyst include: imidazole compounds, triphenylphosphine compounds, amine compounds and trihaloborane compounds.

The volatile component may be an organic compound containing 1 or more hydroxyl groups and having a boiling point of 250 ℃ or higher. The boiling point of the organic compound is preferably 350 ℃ or lower. Examples of such organic compounds include terpene compounds. Among terpene compounds, isobornyl cyclohexanol represented by the following formula (1) is preferable as a volatile component. Isobornyl cyclohexanol is an organic compound having a boiling point of 308 to 318 ℃, has a property of significantly reducing the weight of the isobornyl cyclohexanol from 100 ℃ or higher and of being volatilized and disappeared at 245 ℃ (no further weight loss is observed) when the temperature is raised from room temperature (23 ± 2 ℃) to 600 ℃ under a temperature raising condition of 10 ℃/min under a nitrogen gas flow of 200 mL/min, and has a property of exhibiting an extremely high viscosity of up to 1000000mPa · s at 25 ℃ but a relatively low viscosity of 1000mPa · s or less at 60 ℃. The weight loss is a value when the weight loss ratio at the measurement start temperature (room temperature) is set to 0%.

As described above, isobornyl cyclohexanol exhibits an extremely high viscosity at 25 ℃ and thus can maintain a sheet shape at room temperature, but exhibits a low viscosity at 60 ℃ and thus has stickiness. That is, a thermosetting sheet containing isobornyl cyclohexanol has excellent sheet shape retention at room temperature, and exhibits tackiness at a temperature of 60 ℃ or higher.

Here, when a semiconductor element bonded to one surface of a thermosetting sheet is mounted on a metal lead frame or the like, the semiconductor element is usually temporarily bonded (temporarily fixed) to an adherend such as a metal lead frame via the thermosetting sheet at a temperature of 60 to 80 ℃. That is, in the temporarily bonded state, the mounting position of the semiconductor element is prevented from being displaced, or the thermosetting sheet is prevented from floating from the adherend.

Therefore, when the thermosetting sheet is thermally cured to bond the semiconductor element to the adherend, the bonding can be performed with high reliability.

As the inorganic particles, both conductive particles and non-conductive particles can be used. In the present specification, the conductive particles mean particles having an electrical conductivity of 100 μ S/cm or less as measured in accordance with JIS K0130 (2008), and the non-conductive particles mean particles having an electrical conductivity of more than 100 μ S/cm as measured in accordance with JIS K0130 (2008).

Examples of the non-conductive particles include alumina and boron nitride. The aforementioned nonconductive particles may be used alone, or 2 or more kinds may be used in combination.

Examples of the conductive particles include: nickel particles, copper particles, silver particles, aluminum particles, carbon black, carbon nanotubes, metal particles obtained by plating the surface of a metal as a core with a metal such as gold (hereinafter also referred to as plated metal particles), resin particles whose surface is coated with a metal (hereinafter also referred to as metal-coated resin particles), and the like. These conductive particles may be used alone, or 2 or more kinds may be used in combination.

As the plating metal particles, for example, particles obtained by plating nickel particles or copper particles as nuclei with a noble metal such as gold or silver can be used.

As the metal-coated resin particles, for example, particles obtained by coating the surface of resin particles or the like with a metal such as nickel or gold can be used.

As the shape of the conductive particles, for example, flaky, needle-like, filament-like, spherical, or scaly particles can be used, and spherical is preferable from the viewpoint of improving dispersibility and improving filling rate.

The average particle diameter of the inorganic particles is preferably 0.005 μm or more and 30 μm or less, more preferably 0.01 μm or more and 25 μm or less, and still more preferably 0.05 μm or more and 20 μm or less.

The average particle diameter of the conductive particles can be measured, for example, using a laser diffraction/scattering particle size distribution measuring apparatus (MICROTRAC MT3000II series, manufactured by MICROTRAC corp.

The inorganic particles are preferably sintered metal particles. As a result, after the thermosetting sheet is thermally cured, at least a part of the sinterable metal particles contained in the thermosetting sheet can be sintered, and therefore, a heat radiation path can be easily formed in the thickness direction of the thermosetting sheet. This can increase the heat dissipation property of the thermosetting sheet.

Examples of the sinterable metal particles include fine particles made of a metal. Examples of the metal constituting the fine particles include gold, silver, and copper. Of these, silver is preferably used.

In the present specification, the term "sintering particles" means: and particles wherein at least a part of the particles are bonded and consolidated when heated at a temperature not higher than the melting point of the material constituting the particles.

The average particle diameter of the sinterable metal particles is preferably 0.0005 μm or more, more preferably 0.001 μm or more.

The average particle diameter of the sinterable metal particles is preferably 1 μm or less, and more preferably 0.5 μm or less. By setting the average particle diameter of the sinterable metal particles to 1 μm or less, the sinterable metal particles can be more sufficiently sintered with each other at a temperature (for example, 200 ℃) at which the thermosetting resin is cured.

The average particle diameter of the sinterable metal particles can be measured by observing the sinterable metal particles with an SEM (scanning electron microscope). In the observation by SEM, for example, in the case where the sintered metal particles are of a micro size, the observation is preferably performed at 5000 times, in the case where the sintered metal particles are of a submicron size, the observation is preferably performed at 50000 times, and in the case where the sintered metal particles are of a nano size, the observation is preferably performed at 300000 times.

The sintered metal particles may include aggregated nanoparticles obtained by aggregating nanoparticles of a sintered metal. The mass ratio of the sinterable metal particles to the total mass of the conductive metal particles is preferably 50 mass% or more and 90 mass% or less.

In the thermosetting sheet of the present embodiment, the particle filling rate P of the inorganic particles in the cured thermosetting sheet₂A particle filling rate P with respect to the aforementioned inorganic particles in the aforementioned thermosetting sheet before curing₁Ratio P₂/P₁≥1.3。

Such a ratio of the filling ratio of the particles can be obtained by at least one of shrinkage after curing of the thermosetting resin as an essential component (for example, shrinkage due to curing of the epoxy resin) and volatilization at the time of curing of a volatile component as an arbitrary component.

And the particle filling rate P of the inorganic particles in the thermosetting sheet before curing is adjusted₁Particle filling ratio P with inorganic particles in cured thermosetting sheet₂Satisfying the above relationship, the cured thermosetting sheet can have high heat dissipation properties.

In addition, in the case where the thermosetting sheet of the present embodiment contains the sinterable metal particles as the inorganic particles, the inorganic particles form a continuous phase in the thermosetting sheet, and therefore, excellent electrical conductivity and thermal conductivity can be achieved.

Further, since the thermosetting sheet of the present embodiment contains an organic component such as a thermosetting resin in addition to the inorganic particles, the inorganic particles and the organic component are mixed in the thermosetting sheet.

Therefore, the elastic modulus of the sheet can be made low, and the stress generated in the sheet can be relaxed. This can suppress the occurrence of sheet breakage.

The thermosetting sheet of the present embodiment may further contain a thermoplastic resin in addition to the thermosetting resin. The thermoplastic resin functions as a binder. Examples of the thermoplastic resin include: natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, a polybutadiene resin, a polycarbonate resin, a thermoplastic polyimide resin, polyamide 6, a polyamide resin such as polyamide 6, a phenoxy resin, an acrylic resin, a saturated polyester resin such as PET, PBT, a polyamideimide resin, a fluorine resin, and the like. The thermoplastic resin may be used alone, or 2 or more kinds may be used in combination. The thermoplastic resin is preferably an acrylic resin in view of being less in ionic impurities and high in heat resistance, and thus easily ensuring connection reliability by the thermosetting sheet.

The acrylic resin is preferably a polymer containing a monomer unit derived from a (meth) acrylate ester as the largest monomer unit in terms of mass ratio. Examples of the (meth) acrylate include: alkyl (meth) acrylates, cycloalkyl (meth) acrylates, aryl (meth) acrylates, and the like. The acrylic resin may contain a monomer unit derived from another component copolymerizable with the (meth) acrylate. Examples of the other components include: a carboxyl group-containing monomer, an acid anhydride monomer, a hydroxyl group-containing monomer, a glycidyl group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, a functional group-containing monomer such as acrylamide and acrylonitrile, and various polyfunctional monomers. From the viewpoint of achieving high cohesive force in the die attach layer, the acrylic resin is preferably a copolymer of a (meth) acrylate (particularly, an alkyl (meth) acrylate in which the alkyl group has 4 or less carbon atoms), a carboxyl group-containing monomer, a nitrogen atom-containing monomer, and a polyfunctional monomer (particularly, a polyglycidyl-based polyfunctional monomer), and more preferably a copolymer of ethyl acrylate, butyl acrylate, acrylic acid, acrylonitrile, and polyglycidyl (meth) acrylate.

The thermosetting sheet of the present embodiment may contain 1 or 2 or more other components as necessary. Examples of the other components include: a filler dispersant, a flame retardant, a silane coupling agent, and an ion scavenger.

The thickness of the thermosetting sheet of the present embodiment is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. The thickness of the thermosetting sheet is preferably 150 μm or less, more preferably 100 μm or less, and still more preferably 80 μm or less.

By setting the thickness of the thermosetting sheet to 150 μm or less, the thermal conductivity can be further improved.

The thickness of the thermosetting sheet can be determined by measuring the thickness of any 5 randomly selected points using a dial gauge (model R-205, manufactured by PEACOCK corporation) and arithmetically averaging the thicknesses.

[ dicing die-bonding film ]

Next, the dicing die-bonding film 20 will be described with reference to fig. 1. In the following description, the description of the portion overlapping with the thermosetting sheet will not be repeated.

As shown in fig. 1, the dicing die-bonding film 20 of the present embodiment includes a base material layer 1, a dicing tape 10 in which a pressure-sensitive adhesive layer 2 is laminated on the base material layer 1, and a thermosetting sheet 3 laminated on the pressure-sensitive adhesive layer 2 of the dicing tape 10.

The dicing die-bonding film 20 attaches a semiconductor element on the thermosetting sheet 2. The semiconductor device may be a bare wafer.

The bare wafer bonded to the dicing die-bonding film 20 of the present embodiment is diced by dicing with a blade to cut off the bare chips. In addition, when the thermosetting sheet 2 is cut by blade dicing, the thermosetting sheet is also cut together with the bare wafer. The thermosetting sheet 2 is cut into a size corresponding to the size of the plurality of singulated bare chips. This can obtain a bare chip with the thermosetting sheet 3.

The thermosetting sheet 3 for dicing the die-bonding film 20 contains the thermosetting resin and the inorganic particles as essential components and contains the volatile component as an optional component, as described above, and the particle filling rate P of the inorganic particles in the cured thermosetting sheet₂A particle filling rate P with respect to the aforementioned inorganic particles in the aforementioned thermosetting sheet before curing₁Ratio P₂/P₁≥1.3。

The base material layer 1 supports the adhesive layer 2 and the thermosetting sheet 3 laminated on the adhesive layer 2. The base material layer 1 contains a resin. Examples of the resin include: olefin resins such as Polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers; copolymers containing ethylene as a monomer component, such as ethylene-vinyl acetate copolymers (EVA), ionomer resins, ethylene- (meth) acrylic acid copolymers, and ethylene- (meth) acrylate (random, alternating) copolymers; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); an acrylic resin; polyvinyl chloride (PVC); a polyurethane; a polycarbonate; polyphenylene Sulfide (PPS); amide resins such as polyamide and wholly aromatic polyamide (aramid); polyetheretherketone (PEEK); a polyimide; a polyetherimide; polyvinylidene chloride; ABS (acrylonitrile-butadiene-styrene copolymer); cellulose-based resins; a silicone resin; fluorine resins, and the like.

Of these, polyethylene terephthalate is preferably contained.

The substrate layer 1 may contain 1 kind of the resin, or may contain 2 or more kinds of the resin.

Examples of the material of the base layer 1 include polymers (e.g., plastic films) such as crosslinked products of the above resins. The plastic film may be used without stretching, or a film subjected to a unidirectional or bidirectional stretching treatment as required may be used. By thermally shrinking the base material layer 1 after dicing using a resin sheet provided with heat shrinkability by a stretching treatment or the like, the bonding area between the adhesive layer 2 and the thermosetting sheet 3 can be reduced, and the semiconductor chip (semiconductor element) can be easily recovered.

The surface of the base material layer 1 may be subjected to a conventional surface treatment for the purpose of improving adhesion to an adjacent layer, retention, and the like. Examples of such surface treatment include: chemical or physical treatments such as chromic acid treatment, ozone exposure, flame exposure, high-voltage shock exposure, and ionizing radiation treatment, coating treatment with a primer, and the like.

The thickness of the base material layer 1 is preferably 1 μm or more and 1000 μm or less, more preferably 10 μm or more and 500 μm or less, further preferably 20 μm or more and 300 μm or less, and particularly preferably 30 μm or more and 200 μm or less.

The thickness of the substrate layer 1 can be determined by using a dial gauge (model R-205, manufactured by PEACOCK corporation) in the same manner as the thickness of the thermosetting sheet 2.

The base material layer 1 may contain various additives. Examples of the various additives include: coloring agent, filler, plasticizer, anti-aging agent, antioxidant, surfactant, flame retardant, etc.

The adhesive used for forming the adhesive layer 2 is not particularly limited, and a conventional pressure-sensitive adhesive such as an acrylic adhesive or a rubber adhesive can be used. As the pressure-sensitive adhesive, an acrylic adhesive containing an acrylic polymer as a base polymer is preferable from the viewpoint of the detergency of electronic parts such as semiconductor wafers and glass which are likely to be contaminated with an organic solvent such as ultrapure water or alcohol.

Examples of the acrylic polymer include acrylic polymers using 1 or 2 or more kinds of alkyl (meth) acrylates and cycloalkyl (meth) acrylates as monomer components. Examples of the alkyl (meth) acrylate include methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, sec-butyl ester, tert-butyl ester, pentyl ester, isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester, octadecyl ester, and eicosyl ester, which are linear or branched alkyl esters having 1 to 30 carbon atoms, particularly 4 to 18 carbon atoms. Examples of the cycloalkyl (meth) acrylate include cyclopentyl and cyclohexyl.

The term (meth) acrylate refers to at least one of acrylate and methacrylate, and all (meth) acrylates of the present invention are the same as described above.

The acrylic polymer may contain units corresponding to other monomer components copolymerizable with the alkyl (meth) acrylate or cycloalkyl (meth) acrylate, as necessary, for the purpose of modifying the cohesive strength, heat resistance, and the like. Examples of such monomer components include: carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; anhydride monomers such as maleic anhydride and itaconic anhydride; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; sulfonic acid-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acryloyloxynaphthalenesulfonic acid, (meth) acryloyloxypropyl acrylate, and (meth) acryloyloxynaphthalenesulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; acrylamide, acrylonitrile, and the like. These copolymerizable monomer components may be used in 1 kind or 2 or more kinds. The amount of the copolymerizable monomer is preferably 40% by mass or less of the total monomer components.

The acrylic polymer may further contain a polyfunctional monomer or the like as a comonomer component for crosslinking, if necessary. Examples of such polyfunctional monomers include: hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate, and the like. These polyfunctional monomers may be used in 1 or 2 or more. The amount of the polyfunctional monomer used is preferably 30% by mass or less of the total monomer components from the viewpoint of adhesive properties and the like.

The acrylic polymer can be obtained by polymerizing a single monomer or a mixture of 2 or more monomers. The polymerization may be carried out by any method such as solution polymerization, emulsion polymerization, bulk polymerization, or suspension polymerization. From the viewpoint of preventing contamination of a clean adherend, etc., it is preferable that the content of the low molecular weight substance is small. From this point of view, the number average molecular weight of the acrylic polymer is preferably 30 ten thousand or more, and more preferably about 40 to 300 ten thousand.

In the adhesive, an external crosslinking agent may be added as appropriate in order to increase the number average molecular weight of an acrylic polymer or the like as a base polymer. Specific examples of the external crosslinking method include a method in which a crosslinking agent such as a polyisocyanate compound, an epoxy compound, an aziridine compound or a melamine crosslinking agent is added to the reaction mixture to carry out the reaction. In the case of using an external crosslinking agent, the amount thereof is appropriately determined in consideration of the balance with the base polymer to be crosslinked and the use as an adhesive. In general, the external crosslinking agent is preferably contained in an amount of about 5 parts by mass or less, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the base polymer.

The binder may contain, in addition to the above components, various known additives such as an adhesion promoter and an antioxidant, as required.

The pressure-sensitive adhesive layer 2 may be formed of a radiation-curable pressure-sensitive adhesive. The radiation-curable pressure-sensitive adhesive can increase the crosslinking degree and easily decrease the adhesive force thereof by irradiation with radiation such as ultraviolet rays. That is, by forming the pressure-sensitive adhesive layer 2 from a radiation-curable pressure-sensitive adhesive, the thermosetting sheet 3 is sufficiently adhered to the pressure-sensitive adhesive layer 2 without irradiating the pressure-sensitive adhesive layer 2 with radiation before dicing, and the adhesive force of the pressure-sensitive adhesive layer 2 is reduced by irradiating the pressure-sensitive adhesive layer 2 with radiation after dicing, whereby the semiconductor chips (semiconductor elements) can be easily picked up (recovered).

The radiation-curable pressure-sensitive adhesive is not particularly limited as long as it has a radiation-curable functional group such as a carbon-carbon double bond and exhibits adhesiveness. Examples of the radiation-curable pressure-sensitive adhesive include: an addition type radiation curable pressure sensitive adhesive obtained by blending a radiation curable monomer component and an oligomer component with a conventional pressure sensitive adhesive such as an acrylic pressure sensitive adhesive and a rubber pressure sensitive adhesive.

Examples of the radiation-curable monomer component include: urethane (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 4-butanediol di (meth) acrylate, and the like. Further, examples of the radiation-curable oligomer component include: the molecular weight of various oligomers such as polyurethanes, polyethers, polyesters, polycarbonates, and polybutadienes is preferably in the range of about 100 to 30000. The amount of the radiation-curable monomer component and the radiation-curable oligomer component to be blended is preferably an amount that can suitably reduce the adhesive force of the adhesive layer 2 after irradiation with radiation. In general, the amount of the radiation-curable monomer component and the radiation-curable oligomer component blended is, for example, preferably 5 to 500 parts by mass, and more preferably 40 to 150 parts by mass, per 100 parts by mass of a base polymer such as an acrylic polymer constituting the pressure-sensitive adhesive.

In addition to the additive type radiation curable pressure-sensitive adhesives, examples of the radiation curable pressure-sensitive adhesives include internal type radiation curable pressure-sensitive adhesives in which a polymer having a carbon-carbon double bond in a side chain or a main chain of the polymer or at a terminal of the main chain is used as a base polymer. The internal radiation-curable pressure-sensitive adhesive does not need to contain an oligomer component or the like which is a low-molecular component, or contains a small amount of the oligomer component or the like. Therefore, when the internal radiation curing type pressure-sensitive adhesive is used, the oligomer component and the like can be prevented from moving in the pressure-sensitive adhesive layer 2 with the passage of time. As a result, the adhesive layer 2 can be made to have a relatively stable layer structure.

The base polymer having a carbon-carbon double bond may be used without particular limitation as long as it has a carbon-carbon double bond and has adhesive properties. As such a base polymer, a polymer having an acrylic polymer as a basic skeleton is preferable. The basic skeleton of the acrylic polymer is exemplified by the acrylic polymers described above.

The method for introducing a carbon-carbon double bond into the acrylic polymer is not particularly limited, and various methods can be employed, and if a method for introducing a carbon-carbon double bond into a polymer side chain is employed, molecular design is facilitated. Examples of the method include the following: an acrylic polymer and a monomer having a functional group are copolymerized in advance, and then a compound having a functional group reactive with the functional group and a carbon-carbon double bond is subjected to a condensation reaction or an addition reaction while maintaining the radiation curability of the carbon-carbon double bond.

Examples of combinations of these functional groups include: carboxylic acid groups and epoxy groups, carboxylic acid groups and aziridine groups, hydroxyl groups and isocyanate groups, and the like. Among these combinations of functional groups, a combination of a hydroxyl group and an isocyanate group is preferable from the viewpoint of easiness of reaction follow-up. In addition, as long as the combination of these functional groups is a combination for producing the acrylic polymer having a carbon-carbon double bond, either one of the functional groups may be located on the side of the acrylic polymer or on the side of the compound having a carbon-carbon double bond. In this case, examples of the isocyanate compound having a carbon-carbon bond include: methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, m-isopropenyl- α, α -dimethylbenzyl isocyanate, and the like. Further, as the acrylic polymer, a polymer obtained by copolymerizing the above-mentioned hydroxyl group-containing monomer, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, an ether compound of diethylene glycol monovinyl ether, or the like can be used.

The internal radiation-curable pressure-sensitive adhesive may use the base polymer having a carbon-carbon double bond (particularly, an acrylic polymer) alone, or may contain the radiation-curable monomer component and the radiation-curable oligomer component to such an extent that the properties are not deteriorated. The radiation-curable oligomer component is usually contained in an amount of 30 parts by mass or less, preferably 1 to 10 parts by mass, based on 100 parts by mass of the base polymer.

The radiation-curable pressure-sensitive adhesive contains a photopolymerization initiator when cured by ultraviolet rays or the like. Examples of the photopolymerization initiator include: α -ketol compounds such as 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α -hydroxy- α, α' -dimethylacetophenone, 2-methyl-hydroxypropiophenone, and 1-hydroxycyclohexyl phenyl ketone; acetophenone compounds such as methoxyacetophenone, 2-dimethoxy-2-phenylacetophenone, 2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl ] -2-morpholinopropane-1 and the like; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether; ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; optically active oximes such as 1-phenone-1, 1-propanedione-2- (O-ethoxycarbonyl) oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3, 3' -dimethyl-4-methoxybenzophenone; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2, 4-dimethylthioxanthone, isopropylthioxanthone, 2, 4-dichlorothioxanthone, 2, 4-diethylthioxanthone and 2, 4-diisopropylthioxanthone; camphorquinone; a halogenated ketone; acyl phosphine oxides; acyl phosphonates and the like. The amount of the photopolymerization initiator is, for example, 0.05 to 20 parts by mass per 100 parts by mass of a base polymer such as an acrylic polymer constituting the adhesive.

Examples of the radiation-curable pressure-sensitive adhesive include the following ones disclosed in jp-a 60-196956: rubber-based adhesives and acrylic adhesives containing an addition polymerizable compound having 2 or more unsaturated bonds, a photopolymerizable compound such as an alkoxysilane having an epoxy group, and a photopolymerization initiator such as a carbonyl compound, an organic sulfur compound, a peroxide, an amine, and an onium salt compound.

When curing inhibition by oxygen occurs during irradiation with radiation, it is desirable that the surface of the radiation-curable pressure-sensitive adhesive layer 2 be blocked with oxygen (air) by some method. Examples thereof include: a method of coating the surface of the pressure-sensitive adhesive layer 2 with a spacer, a method of irradiating the surface with a radiation such as ultraviolet rays in a nitrogen atmosphere, and the like.

The thickness of the pressure-sensitive adhesive layer 2 is not particularly limited, but is preferably 1 to 50 μm, more preferably 2 to 30 μm, and still more preferably 5 to 25 μm, from the viewpoint of both preventing chipping of the die-cut section and securing and holding properties of the thermosetting sheet 3.

The matters disclosed in the present specification include the following.

(1)

A thermosetting sheet material is provided which comprises a base material,

which contains a thermosetting resin and inorganic particles as essential components and contains a volatile component as an arbitrary component,

a particle filling ratio P of the inorganic particles in the cured thermosetting sheet₂A particle filling rate P with respect to the aforementioned inorganic particles in the aforementioned thermosetting sheet before curing₁Ratio P₂/P₁≥1.3。

According to this aspect, the volume of the cured thermosetting sheet is reduced by at least one of shrinkage of the thermosetting resin as an essential component after curing and volatilization of the volatile component as an optional component during curing, and as a result, the particle filling rate P of the inorganic particles in the cured thermosetting sheet can be made smaller₂A particle filling rate P with respect to the aforementioned inorganic particles in the aforementioned thermosetting sheet before curing₁Ratio P₂/P₁≥1.3。

Therefore, the particle filling rate of the inorganic particles in the cured thermosetting sheet can be made high.

This makes it possible to increase the heat dissipation property of the cured thermosetting sheet.

(2)

The thermosetting sheet according to the above (1),

which contains the above-mentioned volatile components as essential components,

the volatile component contains 1 or more hydroxyl groups and has a boiling point of 250 ℃ or higher.

According to this embodiment, since the thermosetting sheet further contains a volatile component which contains 1 or more hydroxyl groups and has a boiling point of 250 ℃ or higher, the heat dissipation property of the cured thermosetting sheet can be further improved.

(3)

The thermosetting sheet according to the above (1) or (2), wherein,

the volatile component is terpene compound.

According to this embodiment, since the volatile component is a terpene compound, the heat dissipation property of the cured thermosetting sheet can be further improved.

(4)

The thermosetting sheet according to the above (3), wherein,

the terpene compound is isobornyl cyclohexanol represented by the following formula (1).

According to this embodiment, the temporary adhesion to an adherend such as a metal lead frame is further improved. That is, in the temporarily bonded state, the mounting position of the semiconductor element is prevented from being displaced, or the thermosetting sheet is prevented from floating from the adherend.

Therefore, when the thermosetting sheet is thermally cured to bond the semiconductor element to the adherend, the bonding can be performed with high reliability.

(5)

The thermosetting sheet according to any one of the above (1) to (4), wherein,

the inorganic particles are sintered metal particles.

(6)

The thermosetting sheet according to the above (5), wherein

The aforementioned sinterable metal particles contain silver.

According to this aspect, since the conductive particles are sintered metal particles, at least a part of the conductive particles can be sintered in the cured thermosetting sheet. As a result, the heat dissipation path can be more sufficiently formed in the thickness direction of the cured thermosetting sheet.

This makes it possible to improve the heat dissipation property of the cured thermosetting sheet.

(7)

The thermosetting sheet according to any one of the above (1) to (6), wherein

A particle filling ratio P of the inorganic particles in the cured thermosetting sheet₂40% by volume or more.

According to this embodiment, the particle filling ratio P of the inorganic particles in the cured thermosetting sheet is₂The content of the thermosetting resin is 40 vol% or more, and therefore, the heat dissipation property of the cured thermosetting sheet can be further improved.

(8)

A dicing die-bonding film comprising:

a base material layer,

A dicing tape having a pressure-sensitive adhesive layer laminated on the base material layer, and

a thermosetting sheet laminated on the adhesive layer of the dicing tape,

the thermosetting sheet described above is the thermosetting sheet described in any one of (1) to (7) above.

According to this aspect, after curing, a dicing die-bonding film provided with a thermosetting sheet exhibiting high heat dissipation properties can be formed.

The thermosetting sheet and the dicing die-bonding film of the present invention are not limited to the above embodiments. The thermosetting sheet and the dicing die-bonding film of the present invention are not limited to the above-described effects. The thermosetting sheet and the dicing die-bonding film of the present invention can be variously modified within a range not departing from the gist of the present invention.

Examples

The present invention will be described more specifically with reference to examples. The following examples are intended to illustrate the present invention in more detail, and do not limit the scope of the present invention.

[ example 1]

Varnishes were prepared by stirring a mixture containing the respective materials at mass ratios shown in example 1 of Table 1 below for 3 minutes using a mixer-agitator (trade name: HM-500, manufactured by Kinz corporation). This varnish was applied to one surface of a release-treated film (product name: MRA38, thickness 38 μm, manufactured by Mitsubishi chemical corporation) and dried at 100 ℃ for 2 minutes to obtain a thermosetting sheet having a thickness of 30 μm.

As each material shown in table 1 below, the following products were used.

Phenol formaldehyde resin

MEHC-7851S (biphenyl type phenol resin, phenol equivalent 209g/eq) manufactured by Minghe chemical Co., Ltd

Solid epoxy resin

KI-3000-4 (cresol novolac type multifunctional epoxy resin, epoxy equivalent 200g/eq) manufactured by Nissian Ciki chemical Co., Ltd

Liquid epoxy resins

EXA-4816 (aliphatic modified bisphenol A type epoxy resin (2-functional type), epoxy equivalent 403g/eq) manufactured by DIC corporation

Dispersing agent for fillers

UC-3510 (acrylic Polymer (acrylic resin)) manufactured by Toyo Synthesis Co., Ltd

Silver-coated copper particles

10% Ag/1200YP (flat copper particles (1200YP) coated with 10 mass% silver particles, irregular shape having an average particle diameter of 3.5 μm), manufactured by Mitsui Metal mining Co., Ltd.)

Silver particles

SPH02J (aggregate Nano Ag particles, irregular shape, average particle size of aggregate 1.8 μm) manufactured by Mitsui Metal mining Co., Ltd

Isobornyl cyclohexanol (MTPH)

MTPH manufactured by Nippon Terpene Chemicals, Inc

Acrylic resin solution

Teisan Resin SG-70L (solvent containing MEK and toluene, solid content 12.5%, glass transition temperature-13 ℃, mass average molecular weight 90 ten thousand, acid value 5mg/KOH, carboxyl group-containing acrylic copolymer) manufactured by Nagase ChemteX Corporation

Coupling agent

KBE-846 (bis (triethoxysilylpropyl) tetrasulfide, manufactured by shin Etsu chemical Co., Ltd.)

Catalyst (b)

TPP-K (tetraphenylphosphonium tetraphenylborate), manufactured by Beixing chemical industries, Ltd

Solvent(s)

Methyl ethyl ketone

Table 2 below shows the mass ratio of the silver particles (aggregated nanoparticles) to the total mass of the metal particles (silver-coated copper particles and silver particles (aggregated nanoparticles)), and the mass ratio of isobornyl cyclohexanol to the total mass of the organic components (phenol resin, epoxy resin (solid and liquid), acrylic resin solution, and isobornyl cyclohexanol).

[ example 2]

A thermosetting sheet of example 2 was obtained in the same manner as in example 1, except that a mixture containing the respective materials in the mass ratio shown in example 2 of table 1 below was used.

[ example 3]

A thermosetting sheet of example 3 was obtained in the same manner as in example 1, except that a mixture containing the respective materials in the mass ratio shown in example 3 of table 1 below was used.

[ example 4]

A thermosetting sheet of example 4 was obtained in the same manner as in example 1, except that a mixture containing the respective materials in the mass ratio shown in example 4 of table 1 below was used.

Comparative example 1

A thermosetting sheet of comparative example 1 was obtained in the same manner as in example 1 except that a mixture containing the respective materials in the mass ratio shown in one item of comparative example 1 in table 1 below was used.

[ Table 1]

	Unit of	Example 1	Example 2	Example 3	Example 4	Comparative example 1
							Phenolic resin	Mass portion of	1.00	0.55	0.55	1.18	1.66
Solid epoxy resin	Mass portion of	0.49	0.26	0.26	0.56	0.8
							Liquid epoxy resin	Mass portion of	1.00	0.55	0.55	1.18	1.65
Filler dispersants	Mass portion of	0.16	0.09	0.09	0.19	0.16
							Silver-coated copper particles	Mass portion of	6.62	7.39	2.46	2.71	6.70
Silver particles	Mass portion of	15.46	17.24	22.17	24.35	15.63
							Isobornyl cyclohexanol (MTPH)	Mass portion of	5.00	2.73	2.70	1.56	0
Acrylic resin solution	Mass portion of	5.00	2.73	2.73	5.84	8.24
							Coupling agent	Mass portion of	0.14	0.08	0.08	0.17	0.14
Catalyst and process for preparing same	Mass portion of	0.003	0.002	0.002	0.004	0.005
							Methyl ethyl ketone (MEK, solvent)	Mass portion of	13.1	13.1	13.1	19.6	13.1

< filling ratio of Metal particles >

The thermosetting sheet before curing was subjected to mechanical polishing to expose the Cross section, and the exposed Cross section was subjected to ion polishing using an ion polishing apparatus (trade name: Cross section Polisher SM-09010, manufactured by Nippon electronic Co., Ltd.).

Next, an SEM image (an image based on a scanning electron microscope) within an arbitrary cross-sectional area in the ion-polished exposed cross-section was taken using a field emission type scanning electron microscope SU8020 (manufactured by High-Technologies Corporation), and a reflection electron image was obtained as image data. The shooting conditions adopt accelerating voltage of 5kV and multiplying power of 5000 times.

Then, the obtained image data was subjected to an automatic binarization process for binarizing into a metal portion and a resin portion using image analysis software ImageJ.

Then, the total area of the metal portions and the area of the whole (metal portion + resin portion) are obtained from the binarized image, and the total area of the metal portions is divided by the area of the whole, thereby obtaining the filling rate P of the metal particles with respect to the thermosetting sheet before curing₁。

The filling ratio P of the metal particles₁The filling factor was determined by arithmetically averaging the filling factors determined for 5 cross-sectional areas in the ion-polished exposed cross-section.

The same procedure as described above was carried out for the cured thermosetting sheet to determine the filling ratio P of the metal particles₂。

< Heat conductivity of thermosetting sheet >

The thermosetting sheets of the respective examples were heat-cured by treating at 200 ℃ for 1 hour while applying a pressure of 0.5MPa to the sheets by means of a pressure cooker. The thermal conductivity of the thermosetting sheets of the respective examples subjected to thermal curing was calculated from the following formula.

Thermal conductivity (W/m.k) is thermal diffusivity (m)²(s). times.specific heat (J/g. DEG C.) times.specific gravity (g/cm)³)

Thermal diffusivity of alpha (m)²/s) by the TWA method (temperature wave thermal analysis, measuring apparatus: ai-Phase-Mobile, ai-Phase co., ltd.)).

Specific heat C_p(J/g. cndot.) was measured by DSC method. Specific heat measurement was performed using DSC6220 manufactured by SII Nanotechnology Inc. under conditions of a temperature rise rate of 10 ℃/min and a temperature range of 20 to 300 ℃ based on the obtained numberThe specific heat was calculated according to the method described in the JIS manual (specific heat capacity measuring method K-7123).

The specific gravity was measured by the archimedes method.

The results of calculating the thermal conductivity of the cured thermosetting sheets of the respective examples are shown in table 2 below.

[ Table 2]

	Unit of	Example 1	Example 2	Example 3	Example 4	Comparative example 1
							Aggregate nanoparticle ratio in metal particles	Mass%	70	70	90	90	0
Ratio of isobornyl cyclohexanol	Mass%	61.6	61.6	61.4	30	0
							Filling rate P2 of solidified metal particles	Volume%	46.4	64.3	64.3	48.8	33.4
Filling ratio P1 of metal particles before solidification	Volume%	22.0	36.6	36.0	35.0	33.4
							Filling ratio P2/P1		2.11	1.76	1.79	1.39	1.00
Thermal conductivity of cured thermoset sheet	W/(mK)	4.29	18.34	17.73	9.75	1.11

As can be seen from Table 2, the filling ratio P of the thermosetting sheet of each example was set to₂/P₁All are above 1.3.

Further, as is clear from Table 2, the thermal conductivity of the thermosetting sheets (after curing) of the examples showed high values (example 1: 4.29W/(m.K), example 2: 18.34W/(m.K), example 3: 17.73W/(m.K), and example 4: 9.75W/(m.K)).

In contrast, the heat conductivity of the thermosetting sheet of comparative example 1 (after curing) was found to exhibit a low value of 1.11W/(m · K).

From the results, it was found that the filling ratio P of the thermosetting sheet was adjusted₂/P₁The heat conductivity of the thermosetting sheet can be increased within a specific range of values, that is, the heat dissipation property of the thermosetting sheet can be improved.

Further, in the thermosetting sheet of each example, the filling ratio P of the metal particles after curing₂In contrast, in the thermosetting sheet of comparative example 1, the filling rate P of the metal particles after curing was 40 vol% or more₂33.4% by volume of less than 40% by volume.

From this fact, it is also found that the heat radiation property of the thermosetting sheet can be improved by setting the filling rate P2 of the metal particles after curing to 40 vol% or more.