WO2022255450A1 - Resin sheet, laminate, and semiconductor device - Google Patents

Resin sheet, laminate, and semiconductor device Download PDF

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Publication number
WO2022255450A1
WO2022255450A1 PCT/JP2022/022489 JP2022022489W WO2022255450A1 WO 2022255450 A1 WO2022255450 A1 WO 2022255450A1 JP 2022022489 W JP2022022489 W JP 2022022489W WO 2022255450 A1 WO2022255450 A1 WO 2022255450A1
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WO
WIPO (PCT)
Prior art keywords
resin sheet
boron nitride
melt viscosity
nitride particles
laminate
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PCT/JP2022/022489
Other languages
French (fr)
Japanese (ja)
Inventor
翔平 水野
亜希 高麗
圭吾 大鷲
雄輝 金島
Original Assignee
積水化学工業株式会社
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Application filed by 積水化学工業株式会社 filed Critical 積水化学工業株式会社
Priority to JP2023525911A priority Critical patent/JPWO2022255450A1/ja
Priority to CN202280036578.5A priority patent/CN117397371A/en
Priority to KR1020237041134A priority patent/KR20240017803A/en
Publication of WO2022255450A1 publication Critical patent/WO2022255450A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • H05K1/0313—Organic insulating material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/10—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/12—Mountings, e.g. non-detachable insulating substrates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
    • H01L23/3737—Organic materials with or without a thermoconductive filler
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate

Definitions

  • the present invention relates to a resin sheet, a laminate comprising a cured product of the resin sheet, and a semiconductor device comprising the laminate.
  • Patent Document 1 discloses a method for manufacturing an insulating sheet in which two resin sheets containing an aggregate containing boron nitride and an epoxy resin are laminated and hot-pressed to form an insulating layer.
  • Patent Document 1 describes an invention relating to a method for producing an insulating sheet characterized by adjusting the relationship between the thickness before and after hot pressing and the viscosity at 175°C within a specific range. It is shown that an insulating sheet having excellent thermal conductivity and insulating properties can be obtained by this manufacturing method.
  • an object of the present invention is to provide a resin sheet having excellent insulating properties and thermal conductivity, and excellent adhesion to a metal plate.
  • the present inventors have made intensive studies in order to achieve the above object.
  • the above problem is solved by a resin sheet containing a binder resin and boron nitride particles, wherein the content of the boron nitride particles, the porosity in the cross section of the resin sheet, and the melt viscosity ratio are set to specific ranges.
  • the present invention relates to the following [1] to [14].
  • Melt viscosity ratio [Maximum melt viscosity from 40°C to 195°C (Pa s)]/[Average melt viscosity from 40°C to 100°C (Pa s)] [2]
  • the inorganic filler other than the boron nitride particles is at least one selected from the group consisting of alumina, aluminum nitride, magnesium oxide, diamond, and silicon carbide.
  • [7] A cured product of the resin sheet according to any one of [1] to [6] above.
  • [8] A cured product of the resin sheet according to [7] above, which has a thermal conductivity of 10 W/(m ⁇ K) or more.
  • [9] A cured product of the resin sheet according to [7] or [8] above, a metal base plate, and a metal plate, wherein the cured resin sheet and the metal plate are provided on the metal base plate.
  • Laminates provided in this order.
  • the laminate according to the above [9] wherein the laminate is a circuit board.
  • [11] The laminate according to the above [9] or [10], wherein the metal plate has a circuit pattern.
  • a semiconductor device comprising the laminate according to any one of [9] to [11] above, and a semiconductor element provided on the metal plate.
  • a method for manufacturing a laminate comprising a cured product of a resin sheet, a metal base plate, and a metal plate, wherein the cured product of the resin sheet and the metal plate are provided in this order on the metal base plate, ,
  • the semi-cured resin sheet has a cross-sectional porosity of 0.01% or more and 2.0% or less,
  • the present invention it is possible to provide a resin sheet that is excellent in insulation and thermal conductivity, as well as excellent adhesion to a metal plate.
  • FIG. 1 is a schematic cross-sectional view showing a semiconductor device according to one embodiment of the present invention.
  • FIG. It is an explanatory view explaining a method of tensile shear measurement.
  • the cross-sectional porosity of the resin sheet of the present invention is 0.01% or more and 2.0% or less. If the porosity is more than 2.0%, the ratio of air in the resin sheet increases and the insulating properties deteriorate. On the other hand, if the porosity is less than 0.01%, a phenomenon in which the resin flows out to the side (resin flow) is likely to occur when a metal plate is laminated on the resin sheet, and the insulating properties deteriorate. . From the viewpoint of facilitating suppression of resin flow, the cross-sectional porosity of the resin sheet is preferably 0.05% or more, more preferably 0.1% or more. It is 8% or less, more preferably 1.6% or less.
  • the porosity in the cross section of the resin sheet means the ratio of the area of the voids to the area of the cross section when the cross section of the resin sheet is observed with a scanning electron microscope (SEM). measured by the method
  • SEM scanning electron microscope
  • the melt viscosity ratio of the resin sheet of the present invention is 2 or more. If the melt viscosity ratio is less than 2, the adhesion when laminating the metal plate on the resin sheet is deteriorated. From the viewpoint of improving adhesion, the melt viscosity ratio of the resin sheet is preferably 4 or more, more preferably 6 or more. Although the upper limit of the melt viscosity ratio is not particularly limited, the melt viscosity ratio of the resin sheet is usually 20 or less. The melt viscosity ratio can be adjusted to a desired value by adjusting the conditions for producing the resin sheet described later, specifically the press pressure, press time, press temperature, etc. of the curable resin composition. .
  • the melt viscosity ratio is obtained by the following formula in melt viscosity measurement where the temperature is increased from 40 ° C. to 195 ° C. at a rate of 8 ° C./min. )] / [average melt viscosity from 40 ° C. to 100 ° C. (Pa s)] Specifically, using a rheometer measuring device (manufactured by TA instruments, "ARES"), melting at each temperature under the conditions of an angular velocity of 40 rad/sec, a measurement temperature of 40 to 195 ° C., and a heating rate of 8 ° C./min. Measure the viscosity and determine the melt viscosity ratio. The average melt viscosity at 40 ° C.
  • the binder resin contained in the resin sheet of the present invention is not particularly limited, but is preferably a thermosetting resin. resins, thermosetting polyimide resins, amino alkyd resins, and the like.
  • the binder resin used for the resin sheet may be used singly or in combination of two or more.
  • epoxy resin is preferable among those mentioned above.
  • Epoxy resins include, for example, compounds containing two or more epoxy groups in the molecule.
  • the epoxy resin has a weight average molecular weight of less than 5,000, for example.
  • Specific examples of epoxy resins include styrene skeleton-containing epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, phenol novolac-type epoxy resins, biphenol-type epoxy resins, naphthalene-type epoxy resins, biphenyl-type epoxy resins, fluorene-type epoxy resins, phenol aralkyl-type epoxy resins, naphthol aralkyl-type epoxy resins, dicyclopentadiene-type epoxy resins, anthracene-type epoxy resins, epoxy resins having an adamantane skeleton, epoxy resins having a tricyclodecane skeleton, and epoxy resins having a triazine nucleus in the skeleton, and gly
  • the epoxy equivalent of the epoxy resin is not particularly limited, it is, for example, 70 g/eq or more and 500 g/eq or less.
  • the epoxy equivalent of the epoxy resin is preferably 80 g/eq or more, and preferably 400 g/eq or less, more preferably 350 g/eq or less.
  • an epoxy equivalent can be measured according to the method prescribed
  • the epoxy resins described above may be used singly or in combination of two or more.
  • the content of the binder resin in the resin sheet is not particularly limited, but is preferably 10% by volume or more, more preferably 15% by volume or more, and preferably 50% by volume or less, more preferably 40% by volume or less. be.
  • the content of the binder resin is at least these lower limits, it is possible to sufficiently bind the inorganic filler such as boron nitride particles after curing to obtain a sheet having a desired shape. If the content of the binder resin is not more than these upper limits, a certain amount or more of inorganic filler such as boron nitride particles can be contained, so that it is possible to improve thermal conductivity while improving insulation. can.
  • the binder resin contained in the resin sheet is cured by a curing agent to bind inorganic fillers such as boron nitride particles. That is, the resin sheet according to the present invention preferably further contains a curing agent.
  • curing agents include phenol compounds (phenol heat curing agents), amine compounds (amine heat curing agents), imidazole compounds, acid anhydrides, and the like. Among these, imidazole compounds are preferred. Curing agents may be used singly or in combination of two or more.
  • phenol compounds include novolac-type phenol, biphenol-type phenol, naphthalene-type phenol, dicyclopentadiene-type phenol, aralkyl-type phenol, and dicyclopentadiene-type phenol.
  • Amine compounds include dicyandiamide, diaminodiphenylmethane, diaminodiphenylsulfone, and the like.
  • imidazole compounds include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2 -methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecyl imidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'- Methylimidazolyl-(1′)]
  • Acid anhydrides include styrene/maleic anhydride copolymer, benzophenonetetracarboxylic anhydride, pyromellitic anhydride, trimellitic anhydride, 4,4′-oxydiphthalic anhydride, phenylethynylphthalic anhydride, glycerol.
  • the content of the curing agent relative to the binder resin is not particularly limited as long as the binder resin can be appropriately cured on a volume basis, but is, for example, 0.1 or more and 0.8 or less.
  • the content of the curing agent to the binder resin is preferably 0.15 or more, more preferably 0.2 or more, and preferably 0.6 or less, more preferably 0.5 or less, on a volume basis.
  • the resin sheet of the present invention contains boron nitride particles.
  • the content of the boron nitride particles in the resin sheet is 30% by volume or more and 80% by volume or less.
  • the content of the boron nitride particles is less than 30 volumes, the thermal conductivity of the resin sheet tends to decrease.
  • the content of the boron nitride particles exceeds 80% by volume, the amount of the binder resin is so small that it becomes difficult to obtain a desired shape of the resin sheet and its cured product.
  • the content of boron nitride particles in the resin sheet is preferably 40% by volume or more, more preferably 50% by volume or more, and preferably 75% by volume or less, more preferably 70% by volume or less.
  • the average length of the primary particles of the boron nitride particles is not particularly limited, but is preferably 1 ⁇ m or more, more preferably 1.5 ⁇ m or more, still more preferably 2.0 ⁇ m or more, and more preferably 20 ⁇ m or less, and more preferably It is 15 ⁇ m or less, more preferably 10 ⁇ m or less.
  • the average aspect ratio determined by the major axis and minor axis of the primary particles of boron nitride particles is preferably 1 or more, more preferably 2 or more, and preferably 7 or less, more preferably 6 or less.
  • the average aspect ratio and average major axis are obtained from the major axis and minor axis of the primary particle diameter of the boron nitride particles measured in the cross section exposed by the cross-section polisher. Specifically, it is as follows. First, a cross-section of the cured resin sheet is exposed by a cross-section polisher, and the exposed cross-section is observed with a scanning electron microscope (SEM) at a magnification of 400 to 1200 to obtain an observed image. In the observation image, using image analysis software, the major diameter and minor diameter of the primary particles of 200 boron nitride particles are randomly measured, and the aspect ratio of each particle is calculated from the major diameter / minor diameter. Let the average value of 1 be the average aspect.
  • SEM scanning electron microscope
  • the average value of the major diameters of the measured 200 primary particles is defined as the average major diameter.
  • the major diameter is the length of the longest portion of the observed primary particles of the boron nitride particles in the observation image.
  • the minor axis is the length in the direction perpendicular to the major axis direction in the observed image.
  • the boron nitride particles preferably comprise boron nitride agglomerate particles.
  • Agglomerated boron nitride particles are aggregated particles formed by aggregating primary particles.
  • Boron nitride agglomerated particles can generally be determined whether they are agglomerated particles, for example, by cross-sectional observation with an SEM.
  • the aggregated boron nitride particles may maintain the shape of the aggregated particles, or may be deformed, disintegrated, or crushed through various processes such as press molding.
  • the aggregated boron nitride particles are subjected to a process such as press molding, so that even if they are deformed, collapsed, crushed, etc., they are generally not oriented, and they exist in a certain amount of aggregation. Therefore, for example, by observing the cross section described above, it is suggested that the particles are boron nitride agglomerated particles, and it can be determined whether or not they are agglomerated particles.
  • the aggregated boron nitride particles mixed in the resin sheet preferably have an average particle size of 5 ⁇ m or more, more preferably 10 ⁇ m or more, from the viewpoint of effectively improving insulation and thermal conductivity. It is preferably 200 ⁇ m or less, more preferably 150 ⁇ m or less, and even more preferably 100 ⁇ m or less.
  • the average particle size of aggregated particles can be measured by a laser diffraction/scattering method. Regarding the method of calculating the average particle size, the particle size (d50) of aggregated particles when the cumulative volume is 50% is adopted as the average particle size.
  • the method for producing the aggregated boron nitride particles is not particularly limited, and can be produced by a known method. For example, it can be obtained by aggregating (granulating) primary particles prepared in advance, and specific examples thereof include a spray drying method and a fluid bed granulation method.
  • the spray drying method also called spray drying
  • the spray drying method can be classified into a two-fluid nozzle method, a disk method (also called a rotary method), an ultrasonic nozzle method, etc., and any of these methods can be applied.
  • the granulation step is not necessarily required as a method for producing aggregated boron nitride particles.
  • boron nitride crystals crystallized by a known method grow, the primary particles of boron nitride naturally aggregate to form agglomerated particles.
  • aggregated boron nitride particles include “UHP-G1H” manufactured by Showa Denko KK, “HP-40” manufactured by Mizushima Ferroalloy Co., Ltd., and the like.
  • the resin sheet of the present invention may contain an inorganic filler other than the boron nitride particles in addition to the boron nitride particles described above.
  • an inorganic filler other than boron nitride particles a thermally conductive filler may be used.
  • the thermally conductive filler has, for example, a thermal conductivity of 10 W/(m ⁇ K) or more, preferably 15 W/(m ⁇ K) or more, more preferably 20 W/(m ⁇ K) or more.
  • the upper limit of the thermal conductivity of the thermally conductive filler is not particularly limited, it may be, for example, 300 W/(m ⁇ K) or less, or 200 W/(m ⁇ K) or less.
  • Inorganic fillers other than boron nitride particles can enter the gaps between boron nitride particles, such as boron nitride agglomerated particles, to further increase thermal conductivity.
  • the thermal conductivity of the inorganic filler can be measured, for example, by a periodic heating thermoreflectance method using a thermal microscope manufactured by Bethel Co., Ltd. on a cross section of the filler cut by a cross section polisher.
  • the inorganic filler other than boron nitride particles is preferably at least one selected from the group consisting of alumina, aluminum nitride, magnesium oxide, diamond, and silicon carbide.
  • alumina is preferable among the above from the viewpoint of preventing deterioration of insulating properties while improving thermal conductivity and adhesion to a metal plate.
  • inorganic fillers other than boron nitride particles one type may be used alone, or two or more types may be used in combination.
  • the inorganic filler other than the boron nitride particles may be of any shape, and may be scaly, spherical, crushed, amorphous, polygonal, or aggregated particles.
  • the inorganic filler other than the boron nitride particles preferably has an average aspect ratio of primary particles of 3 or less. Examples of such fillers include spherical fillers. Spherical alumina is more preferable as the spherical filler.
  • the average aspect ratio of primary particles can be measured by cross-sectional observation as described above.
  • the average aspect ratio of inorganic fillers other than boron nitride particles is more preferably 2 or less.
  • the inorganic filler other than boron nitride particles may have an aspect ratio of 1 or more.
  • the use of inorganic fillers other than boron nitride particles having such a low aspect ratio makes it easier to improve thermal conductivity and adhesion to metal plates.
  • the average particle size of the inorganic filler other than the boron nitride particles is preferably 0.1 ⁇ m or more, more preferably 0.2 ⁇ m or more, and even more preferably 0.3 ⁇ m or more. Also, it is preferably 100 ⁇ m or less, more preferably 80 ⁇ m or less, and even more preferably 70 ⁇ m or less. When the average particle size is less than these upper limits, it becomes easier to mix the inorganic filler in the resin sheet at a high filling rate. Moreover, when it is more than a lower limit, it will become easy to improve insulation.
  • the average particle size of inorganic fillers other than boron nitride particles can be measured, for example, by the Coulter Counter method. Inorganic fillers other than boron nitride particles may be used singly or in combination of two or more.
  • the content of inorganic fillers other than boron nitride particles in the resin sheet is, for example, 2% by volume or more and 55% by volume or less. By adjusting the content to such a value, for example, thermal conductivity and adhesion to the metal plate can be further enhanced.
  • the content of inorganic fillers other than boron nitride particles in the resin sheet is preferably 4% by volume or more, more preferably 10% by volume or more, and the content of inorganic fillers other than boron nitride particles is preferably 55% by volume. %, and more preferably 45% by volume or less from the viewpoint of making it easier to ensure thermal conductivity by containing a certain amount or more of boron nitride particles.
  • the volume ratio of the inorganic filler other than boron nitride particles to the boron nitride particles is, for example, 0.005 or more 4 It is below. By setting it within this range, it becomes easier to suppress the deterioration of the insulation due to heating while further increasing the thermal conductivity and the adhesion to the metal plate. From such a viewpoint, the ratio is preferably 0.01 or more, more preferably 0.1 or more, still more preferably 0.3 or more, and preferably 3 or less, more preferably 2 or less, and further preferably 1 or less.
  • the total content of the boron nitride particles and the inorganic filler other than the boron nitride particles in the resin sheet is preferably 65% by volume or more. When it is 65 volumes or more, it is possible to ensure even higher heat dissipation performance. Further, the total content of the boron nitride particles and the inorganic filler other than the boron nitride particles in the resin sheet is preferably 80% by volume or less. By making it 80% by volume or less, the adhesion of the resin sheet to the metal plate is further improved. From such a viewpoint, the content of the inorganic filler is preferably 78% by volume or less, more preferably 75% by volume or less, and even more preferably 70% by volume or less.
  • the resin sheet according to the present invention contains a dispersant, a curing accelerator, a coupling agent such as a silane coupling agent, a flame retardant, an antioxidant, an ion scavenger, a tackifier, a plasticizer, Other additives such as thiso-imparting agents and colorants may also be included.
  • the thickness of the resin sheet of the present invention is not particularly limited, it is, for example, 50 ⁇ m or more and 500 ⁇ m or less. When the thickness is 50 ⁇ m or more, it becomes easy to secure a certain level of insulation and heat dissipation, and when the thickness is 500 ⁇ m or less, it becomes easy to thin a circuit board or a semiconductor device, which will be described later.
  • the thickness of the insulating resin sheet is preferably 60 ⁇ m or more, more preferably 70 ⁇ m or more, and preferably 400 ⁇ m or less, more preferably 200 ⁇ m or less.
  • the resin sheet of the present invention is formed of a curable resin composition containing a binder resin, boron nitride particles, and optionally an inorganic filler other than the boron nitride particles, a curing agent, and other additives.
  • the method of forming the resin sheet from the curable resin composition is not particularly limited, but for example, the curable resin composition is coated on a support such as a release sheet, and the dried coating is heated under predetermined conditions. press.
  • the curable resin composition may be diluted with a diluting solvent, applied to a support or the like, and dried.
  • the conditions for hot pressing may be appropriately adjusted according to the type of binder resin, the content of boron nitride particles, etc., so as to achieve a predetermined melt viscosity ratio and void ratio, and are not limited, but for example the following: should be adjusted as follows.
  • the press pressure is, for example, 5 MPa or more and 30 MPa or less, preferably 15 MPa or more and 25 MPa or less
  • the press temperature is, for example, 60° C. or more and 130° C. or less, preferably 70° C. or more and 110° C. or less
  • the press time is, for example, 20 minutes or more and 120 minutes or less, preferably 30 minutes. minutes or more and 100 minutes or less.
  • the binder resin contained in the resin sheet formed by hot pressing is in an uncured state or in a partially cured state. In this specification, the partially cured state is also referred to as a semi-cured state.
  • the specific method of hot pressing is not particularly limited, but the following method is preferable from the viewpoint of improving the manufacturing yield.
  • a sample in which a curable resin composition is applied onto a support such as a release sheet (e.g., a release PET sheet) and dried to form a coating film (a sample having a coating film formed on the support) are prepared, and a laminate is prepared by laminating the two samples so that the coating films are in contact with each other. Both surfaces of the laminate are sandwiched between two metal plates and hot-pressed. Since the resin sheet manufactured by such a method has a two-layer structure, it is possible to reduce the frequency of manufacturing a resin sheet having pinholes formed therein.
  • the resin sheet in the present invention can be cured by heating at a temperature equal to or higher than the curing temperature of the binder resin to obtain a cured product of the resin sheet. Curing is preferably carried out by heating under pressure. A cured product of the resin sheet can constitute a part of a laminate to be described later.
  • the thermal conductivity of the cured resin sheet is preferably 10 W/(m ⁇ K) or more. By setting the thermal conductivity to 10 W/(m ⁇ K) or more, the heat radiation performance is excellent, and when used as a circuit board, the heat generated by the elements mounted on the circuit board is efficiently released to the outside.
  • the thermal conductivity of the cured resin sheet is more preferably 11 W/(m ⁇ K) or higher, still more preferably 12 W/(m ⁇ K) or higher, and even more preferably 15 W/(m ⁇ K) or higher.
  • the upper limit of the thermal conductivity of the cured resin sheet is not particularly limited, but is practically about 30 W/(m ⁇ K), for example.
  • the thermal conductivity of the cured product of the resin sheet it is preferable to measure the thermal conductivity in the thickness direction by a laser flash method.
  • the laminate of the present invention comprises a metal base plate 11 and a metal plate 12 in addition to the cured resin sheet 10 of the present invention. 10 and a metal plate 12 in this order.
  • the heat conductivity thereof is preferably 10 W/m ⁇ K or more.
  • Materials used for these include metals such as aluminum, copper, gold, and silver, and graphite sheets. Aluminum, copper, or gold is preferred, and aluminum or copper is more preferred, from the viewpoint of more effectively increasing thermal conductivity.
  • the thickness of the metal base plate 11 is preferably 0.1-5 mm, and the thickness of the metal plate 12 is preferably 10-2000 ⁇ m, more preferably 10-900 ⁇ m.
  • the metal plate includes a plate such as a copper plate and a foil such as copper foil.
  • the shape of the metal base plate is not particularly limited, but it may be a flat plate shape, or a shape with a large surface area such as an uneven shape or a bellows shape.
  • the laminate 13 is preferably used as a circuit board.
  • the metal plate 12 in the laminate 13 may have a circuit pattern.
  • the circuit pattern may be appropriately patterned according to the elements to be mounted on the circuit board.
  • the circuit pattern is not particularly limited, but may be formed by etching or the like.
  • the metal base plate 11 is used as a heat sink or the like.
  • a semiconductor device 15 includes a laminate 13 having a cured resin sheet 10, a metal base plate 11, and a metal plate 12, and a semiconductor device 15 provided on the metal plate 12 of the laminate 13. and a semiconductor element 14 formed by a semiconductor device.
  • the metal plate 12 is preferably patterned by etching or the like to have a circuit pattern.
  • each semiconductor element 14 is connected to the metal plate 12 via a connection conductive portion 16 formed on the metal plate 12 .
  • the connection conductive portion 16 is preferably made of solder.
  • a sealing resin 19 is provided on the surface of the laminate 13 on the metal plate 12 side. At least the semiconductor element 14 is sealed with the sealing resin 19 , and the metal plate 12 is preferably sealed together with the semiconductor element 14 with the sealing resin 19 as necessary.
  • the semiconductor elements 14 are not particularly limited, but at least one is preferably a power element (that is, a power semiconductor element), so that the semiconductor device 15 is preferably a power module.
  • Power modules are used, for example, in inverters and the like.
  • the power module is used in industrial equipment such as elevators and uninterruptible power supplies (UPS), but the application is not particularly limited.
  • a lead 20 is connected to the metal plate 12 .
  • the lead 20 extends outside, for example, from the sealing resin 19 and connects the metal plate 12 to an external device or the like.
  • a wire 17 may be connected to the semiconductor element 14 .
  • the wires 17 may connect the semiconductor element 14 to another semiconductor element 14, the metal plate 12, the leads 20, etc., as shown in FIG.
  • the semiconductor element 14 generates heat when it is driven by being supplied with electric power through the leads 20 or the like. Heat is radiated from the plate 11 .
  • the metal base plate 11 may be connected to a heat sink made up of radiation fins or the like, if necessary.
  • the semiconductor device 15 is preferably manufactured through a reflow process in its manufacturing process. Specifically, in the manufacturing method of the semiconductor device 15, first, the laminate 13 is prepared, the connection conductive portion 16 is formed on the metal plate 12 of the laminate 13 by solder printing or the like, and the connection conductive portion 16 is formed. A semiconductor element 14 is mounted on the . After that, the laminate 13 with the semiconductor element 14 mounted thereon is passed through a reflow furnace and heated inside the reflow furnace, and the semiconductor element 14 is connected onto the metal plate 12 by the connecting conductive portions 16 . Although the temperature in the reflow furnace is not particularly limited, it is, for example, about 200 to 300.degree.
  • the semiconductor element 14 may be sealed by laminating the sealing resin 19 on the laminate 13 after the reflow process. Also, before sealing with the sealing resin 19, the wires 17, the leads 20, etc. may be appropriately attached.
  • a mode in which the semiconductor element 14 is connected to the metal plate 12 by the reflow process is shown, but the present invention is not limited to this mode. substrate (not shown).
  • Laminate manufacturing method In the case of producing a laminate comprising a cured resin sheet, a metal base plate, and a metal plate, the resin sheet is placed between the metal base plate and the metal plate, and is heated and pressed by press molding to form the metal base. It is preferable to manufacture a laminate by bonding a plate and a metal plate via a cured resin sheet.
  • the resin sheet is preferably cured by heating during press molding, but may be partially or completely cured before press molding.
  • the porosity in the cross section of the semi-cured resin sheet is 0.01% or more and 2.0% or less, and the melt viscosity is measured from 40 ° C. to 195 ° C. at a temperature increase rate of 8 ° C./min.
  • the press pressure is, for example, 5 MPa or more and 30 MPa or less, preferably 15 MPa or more and 25 MPa or less
  • the press temperature is, for example, 60° C. or more and 130° C. or less, preferably 70° C. or more and 110° C. or less
  • the time may be, for example, 20 minutes or more and 120 minutes or less, preferably 30 minutes or more and 100 minutes or less.
  • the press pressure is, for example, 0.5 MPa or more and 20 MPa or less, preferably 1 MPa or more and 10 MPa or less
  • the press temperature is, for example, 120° C. or more and 230° C. or less, preferably 140° C. or more and 220° C. or less
  • the pressing time is, for example, 30 minutes or more and 150 minutes or less, preferably 50 minutes or more and 120 minutes or less.
  • the measuring method and evaluation method of each physical property are as follows.
  • the cross section of the resin sheet produced in each example and comparative example was smoothed with abrasive paper, and an observation surface was produced with a cross section polisher (manufactured by JEOL Ltd., "IB-19500CP"). After that, the observation surface obtained by sputtering the cross section with a Pt ion sputter (E-1045, manufactured by Hitachi High-Technologies) was scanned with a scanning electron microscope (SEM) to obtain a 500-fold cross-sectional image so that the entire sheet could be included. rice field. Image processing and analysis were then performed on this image. Using "ImageJ" (developed by Wayne Rasband), the cross-sectional image was binarized into voids and other regions by the Threshold function, and the porosity was obtained from the area ratio of voids to the cross-sectional area.
  • melt viscosity ratio [Maximum melt viscosity from 40°C to 195°C (Pa s)]/[Average melt viscosity from 40°C to 100°C (Pa s)]
  • a ⁇ 2 circular electrode was formed on each laminate (6 cm ⁇ 6 cm) produced in Examples and Comparative Examples, and a voltage was applied to the electrode at a rate of 20 kV/min.
  • the voltage at which dielectric breakdown occurred in the measurement sample was defined as the dielectric breakdown voltage, and evaluation was made based on the following evaluation criteria. (Evaluation criteria) A: 2 kV or more B: less than 2 kV
  • the tensile shear measurement was performed by preparing a sample for tensile shear measurement as follows, in accordance with JIS K6850. As shown in FIG. 3, samples were prepared by laminating a copper plate 32 and a copper plate 33 on both sides of a resin sheet 31 (thickness: 0.12 mm, length L: 12.5 mm, width: 25 mm) prepared in each example and comparative example. made. Each copper plate is 100 mm long, 25 mm wide and 0.5 mm thick. At this time, as shown in FIG.
  • one end side 32a of the copper plate 32 and one end side 33a of the copper plate 33 are arranged on both sides of the resin sheet 31, and the other end sides 32b and 33b of the respective copper plates are laminated so that they are separated from each other. .
  • the sample prepared in this manner was pressed at 145° C. for 30 minutes under a pressure of 5 MPa, and then pressed at 195° C. for 55 minutes to cure the resin sheet 31 of the sample, thereby preparing a sample for tensile shear measurement.
  • the sample for tensile shear measurement was pulled in the shear direction by a tensile tester, and the maximum strength at that time was taken as the tensile shear force (MPa) and evaluated according to the following criteria.
  • thermosetting component is an epoxy resin and a phenoxy resin. They were used at a volume ratio of 7.4:2.6, respectively.
  • curing agent "HN2200”, “1B2MZ” manufactured by Showa Denko Materials Co., Ltd., and "1B2MZ” manufactured by Shikoku Kasei Co., Ltd. : used at a volume ratio of 1.1.
  • Example 1 The binder resin, inorganic filler, and curing agent shown in Table 1 were mixed in the amounts shown in Table 1 to obtain a curable resin composition.
  • the curable resin composition is applied onto a release PET sheet (40 ⁇ m thick) and dried in an oven at 50° C. for 10 minutes to form a coating film of the curable resin composition on the release PET sheet.
  • Two samples were prepared. The two samples thus prepared are laminated so that the coating films are in contact with each other to prepare a laminate, and after sandwiching the laminate between two metal plates, press pressure 18 MPa, press temperature 100 ° C., press time It was hot pressed under press melting conditions for 45 minutes. Thus, a resin sheet sandwiched between release PET sheets was obtained. Various measurements were performed using the resin sheet.
  • the release PET sheet was peeled off, and both sides of the resin sheet were sandwiched between a first metal layer (copper plate, thickness 500 ⁇ m) and a second metal layer (aluminum plate, thickness 1.0 mm), and subjected to a pressure of 5 MPa. After pressing for 30 minutes at 145° C., pressing was performed at 195° C. for 55 minutes to produce a laminate in which the first metal layer, the cured resin sheet, and the second metal layer were laminated in this order. Various measurements were performed using the laminate.
  • Examples 2 to 12 Comparative Examples 1 to 6
  • a resin sheet and a laminate were prepared in the same manner as in Example 1, except that the type and amount of each component contained in the curable resin composition and the press melting conditions were changed as shown in Tables 1 and 2, and various evaluations were performed. did

Abstract

This resin sheet contains a binder resin and boron nitride particles, wherein the boron nitride particle content is 30-80 vol%, the porosity in the cross-section of the resin sheet is 0.01-2.0%, and the melt viscosity ratio {[maximum melt viscosity (Pa・s) from 40 °C to 195 °C]/[average melt viscosity (Pa・s) from 40 °C to 100 °C]} is at least 2 in a melt viscosity measurement measured from 40 °C to 195 °C at a temperature rise rate of 8 °C/minute.　The present invention can provide a resin sheet having excellent insulation properties and thermal conductivity and excellent adhesiveness to a metal plate.

Description

樹脂シート、積層体、及び半導体装置Resin sheet, laminate, and semiconductor device
　本発明は樹脂シート、該樹脂シートの硬化物を備える積層体、及び該積層体を備える半導体装置に関する。 The present invention relates to a resin sheet, a laminate comprising a cured product of the resin sheet, and a semiconductor device comprising the laminate.
　従来、産業用機器、家庭用電気機器、情報端末などの幅広い分野において、パワーモジュールが用いられている。パワーモジュールでは、基板として樹脂シートを使用する試みがなされており、樹脂シートを用いたパワーモジュールは、例えば高電圧用途への展開が期待されている。このような樹脂シートには、一般に熱伝導性に優れることが求められている。
　このような観点から、樹脂シートに含有させる無機フィラーとして、高い熱伝導率を有する窒化ホウ素を高充填させる技術が知られている。一方、窒化ホウ素を高充填させると、樹脂シートにボイドが形成されやすくなり、絶縁性が低下することがある。 2. Description of the Related Art Conventionally, power modules have been used in a wide range of fields such as industrial equipment, household electrical equipment, and information terminals. Attempts have been made to use resin sheets as substrates in power modules, and power modules using resin sheets are expected to be used for high voltage applications, for example. Such resin sheets are generally required to have excellent thermal conductivity.
From such a point of view, there is known a technique of highly filling boron nitride having high thermal conductivity as an inorganic filler to be contained in a resin sheet. On the other hand, when the boron nitride is highly filled, voids are likely to be formed in the resin sheet, and the insulating properties may deteriorate.
　この問題を解決する観点から、特許文献１では、窒化ホウ素を含む凝集体とエポキシ樹脂とを含む樹脂シートを２枚積層し、熱プレスすることにより絶縁層を形成させる絶縁シートの製造方法であって、熱プレス前後の厚みの関係や、１７５℃における粘度を特定範囲に調整することを特徴とする絶縁シートの製造方法に関する発明が記載されている。該製造方法によって、熱伝導性及び絶縁性に優れる絶縁シートが得られることが示されている。 From the viewpoint of solving this problem, Patent Document 1 discloses a method for manufacturing an insulating sheet in which two resin sheets containing an aggregate containing boron nitride and an epoxy resin are laminated and hot-pressed to form an insulating layer. Patent Document 1 describes an invention relating to a method for producing an insulating sheet characterized by adjusting the relationship between the thickness before and after hot pressing and the viscosity at 175°C within a specific range. It is shown that an insulating sheet having excellent thermal conductivity and insulating properties can be obtained by this manufacturing method.
特許第６２１４３３６号公報Japanese Patent No. 6214336
　上記した特許文献１に記載の発明によれば、シート中のボイドが一定程度低減され、絶縁性が向上する。しかしながら、近年、従来の絶縁シートよりもより絶縁性の高い樹脂シートが求められている。また、従来技術では、ボイド率と絶縁性の詳細な関係は、何ら明らかにされていない。さらに、樹脂シートには、絶縁性、熱伝導性の他に、回路パターンを形成するための金属板に対して密着性に優れることも必要とされており、これらの物性を満足する樹脂シートの開発が期待されている。
　そこで本発明では、絶縁性及び熱伝導性に優れ、かつ金属板に対して密着性に優れる樹脂シートを提供することを目的とする。 According to the invention described in Patent Document 1, the number of voids in the sheet is reduced to a certain degree, and the insulation is improved. However, in recent years, resin sheets with higher insulating properties than conventional insulating sheets have been desired. Moreover, in the prior art, the detailed relationship between the void fraction and the insulation properties has not been clarified at all. Furthermore, in addition to insulating properties and thermal conductivity, resin sheets are also required to have excellent adhesion to metal plates for forming circuit patterns. Resin sheets that satisfy these physical properties are required. Expected to be developed.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a resin sheet having excellent insulating properties and thermal conductivity, and excellent adhesion to a metal plate.
　本発明者らは、前記目的を達成するために鋭意研究を重ねた。その結果、バインダー樹脂及び窒化ホウ素粒子を含有する樹脂シートであって、窒化ホウ素粒子の含有量、樹脂シートの断面における空隙率、及び溶融粘度比率を特定範囲とした樹脂シートにより、上記課題が解決できること見出し、本発明を完成させた。
　すなわち、本発明は、下記［１］～［１４］に関する。 The present inventors have made intensive studies in order to achieve the above object. As a result, the above problem is solved by a resin sheet containing a binder resin and boron nitride particles, wherein the content of the boron nitride particles, the porosity in the cross section of the resin sheet, and the melt viscosity ratio are set to specific ranges. I discovered what I could do and completed the present invention.
That is, the present invention relates to the following [1] to [14].
［１］バインダー樹脂及び窒化ホウ素粒子を含有する樹脂シートであって、窒化ホウ素粒子の含有量が３０体積％以上８０体積％以下であり、樹脂シートの断面における空隙率が０．０１％以上２．０％以下であり、４０℃から１９５℃まで８℃／分の昇温速度で測定する溶融粘度測定において、下記式で求められる溶融粘度比率が２以上である、樹脂シート。
　溶融粘度比率＝［４０℃から１９５℃における最大溶融粘度（Ｐａ・ｓ）］／［４０℃から１００℃における平均溶融粘度（Ｐａ・ｓ）］　
［２］前記窒化ホウ素粒子以外の無機フィラーを含有する上記［１］に記載の樹脂シート。
［３］前記窒化ホウ素粒子以外の無機フィラーが、アルミナ、窒化アルミニウム、酸化マグネシウム、ダイヤモンド、及び炭化ケイ素からなる群から選択される少なくとも１種である、上記［２］に記載の樹脂シート。
［４］前記窒化ホウ素粒子以外の無機フィラーの含有量が、２体積％以上５５体積％以下である、上記［２］又は［３］に記載の樹脂シート。
［５］前記窒化ホウ素粒子と前記窒化ホウ素粒子以外の無機フィラーとの合計の含有量が、６５体積％以上８０体積％以下である、上記［２］～［４］のいずれか１項に記載の樹脂シート。
［６］前記窒化ホウ素粒子が、窒化ホウ素凝集粒子を含む上記［１］～［５］のいずれか１項に記載の樹脂シート。
［７］上記［１］～［６］のいずれか１項に記載の樹脂シートの硬化物。
［８］熱伝導率が、１０Ｗ／(ｍ・Ｋ）以上である上記［７］に記載の樹脂シートの硬化物。
［９］上記［７］又は［８］に記載の樹脂シートの硬化物と、金属ベース板と、金属板とを備え、前記金属ベース板上に、前記樹脂シートの硬化物と前記金属板をこの順に備える積層体。
［１０］前記積層体が、回路基板である上記［９］に記載の積層体。
［１１］前記金属板が、回路パターンを有する上記［９］又は［１０］に記載の積層体。
［１２］上記［９］～［１１］のいずれか１項に記載の積層体と、前記金属板の上に設けられる半導体素子とを備える半導体装置。
［１３］樹脂シートの硬化物と、金属ベース板と、金属板とを備え、前記金属ベース板上に、前記樹脂シートの硬化物と前記金属板をこの順に備える積層体の製造方法であって、
　バインダー樹脂及び窒化ホウ素粒子を含有する硬化性樹脂組成物を加熱及び加圧することにより半硬化状態の樹脂シートを作製する第１の熱プレス工程と、
　前記半硬化状態の樹脂シートを、前記金属ベース板と前記金属板の間に配置する積層工程と、
　前記積層工程で積層された半硬化状態の樹脂シートを加熱及び加圧することにより本硬化させ積層体を得る第２の熱プレス工程と、を有し、
　前記半硬化状態の樹脂シートの断面における空隙率が０．０１％以上２．０％以下であり、
　４０℃から１９５℃まで８℃／分の昇温速度で測定する溶融粘度測定において、下記式で求められる前記半硬化状態の樹脂シートの溶融粘度比率が２以上である、積層体の製造方法。
溶融粘度比率＝［４０℃から１９５℃における最大溶融粘度（Ｐａ・ｓ）］／［４０℃から１００℃における平均溶融粘度（Ｐａ・ｓ）］
［１４］前記第１の熱プレス工程のプレス温度が６０℃以上１３０℃以下であり、プレス圧力が５ＭＰａ以上３０ＭＰａ以下である、上記［１３］に記載の積層体の製造方法。 [1] A resin sheet containing a binder resin and boron nitride particles, wherein the content of the boron nitride particles is 30% by volume or more and 80% by volume or less, and the porosity in the cross section of the resin sheet is 0.01% or more 2 .0% or less, and a resin sheet having a melt viscosity ratio of 2 or more, as determined by the following formula, in a melt viscosity measurement in which the temperature is increased from 40°C to 195°C at a rate of 8°C/min.
Melt viscosity ratio = [Maximum melt viscosity from 40°C to 195°C (Pa s)]/[Average melt viscosity from 40°C to 100°C (Pa s)]
[2] The resin sheet according to [1] above, which contains an inorganic filler other than the boron nitride particles.
[3] The resin sheet according to [2] above, wherein the inorganic filler other than the boron nitride particles is at least one selected from the group consisting of alumina, aluminum nitride, magnesium oxide, diamond, and silicon carbide.
[4] The resin sheet according to [2] or [3] above, wherein the content of the inorganic filler other than the boron nitride particles is 2% by volume or more and 55% by volume or less.
[5] Any one of [2] to [4] above, wherein the total content of the boron nitride particles and the inorganic filler other than the boron nitride particles is 65% by volume or more and 80% by volume or less. resin sheet.
[6] The resin sheet according to any one of [1] to [5] above, wherein the boron nitride particles contain aggregated boron nitride particles.
[7] A cured product of the resin sheet according to any one of [1] to [6] above.
[8] A cured product of the resin sheet according to [7] above, which has a thermal conductivity of 10 W/(m·K) or more.
[9] A cured product of the resin sheet according to [7] or [8] above, a metal base plate, and a metal plate, wherein the cured resin sheet and the metal plate are provided on the metal base plate. Laminates provided in this order.
[10] The laminate according to the above [9], wherein the laminate is a circuit board.
[11] The laminate according to the above [9] or [10], wherein the metal plate has a circuit pattern.
[12] A semiconductor device comprising the laminate according to any one of [9] to [11] above, and a semiconductor element provided on the metal plate.
[13] A method for manufacturing a laminate comprising a cured product of a resin sheet, a metal base plate, and a metal plate, wherein the cured product of the resin sheet and the metal plate are provided in this order on the metal base plate, ,
A first hot press step of producing a semi-cured resin sheet by heating and pressing a curable resin composition containing a binder resin and boron nitride particles;
a laminating step of disposing the semi-cured resin sheet between the metal base plate and the metal plate;
a second hot press step for obtaining a laminate by heating and pressing the semi-cured resin sheets laminated in the lamination step to obtain a laminate,
The semi-cured resin sheet has a cross-sectional porosity of 0.01% or more and 2.0% or less,
A method for producing a laminate, wherein the melt viscosity ratio of the semi-cured resin sheet obtained by the following formula is 2 or more in a melt viscosity measurement in which the temperature is increased from 40° C. to 195° C. at a rate of 8° C./min.
Melt viscosity ratio = [Maximum melt viscosity from 40°C to 195°C (Pa s)]/[Average melt viscosity from 40°C to 100°C (Pa s)]
[14] The method for producing a laminate according to [13] above, wherein the pressing temperature in the first hot pressing step is 60°C or higher and 130°C or lower, and the pressing pressure is 5 MPa or higher and 30 MPa or lower.
　本発明によれば、絶縁性及び熱伝導性に優れ、かつ金属板に対する密着性に優れる樹脂シートを提供することができる。 According to the present invention, it is possible to provide a resin sheet that is excellent in insulation and thermal conductivity, as well as excellent adhesion to a metal plate.
本発明の一実施形態に係る積層体を示す模式的な断面図である。It is a typical sectional view showing a layered product concerning one embodiment of the present invention. 本発明の一実施形態に係る半導体装置を示す模式的な断面図である。1 is a schematic cross-sectional view showing a semiconductor device according to one embodiment of the present invention; FIG. 引張りせん断測定の方法を説明する説明図である。It is an explanatory view explaining a method of tensile shear measurement.
＜樹脂シート＞
　本発明の樹脂シートは、バインダー樹脂及び窒化ホウ素粒子を含有する樹脂シートであって、窒化ホウ素粒子の含有量が３０体積％以上８０体積％以下、樹脂シートの断面における空隙率が０．０１％以上２．０％以下であり、４０℃から１９５℃まで８℃／分の昇温速度で測定する溶融粘度測定において、下記式で求める溶融粘度比率が２以上である。
　溶融粘度比率＝［４０℃から１９５℃における最大溶融粘度（Ｐａ・ｓ）］／［４０℃から１００℃における平均溶融粘度（Ｐａ・ｓ）］ <Resin sheet>
The resin sheet of the present invention is a resin sheet containing a binder resin and boron nitride particles, the content of the boron nitride particles is 30% by volume or more and 80% by volume or less, and the porosity in the cross section of the resin sheet is 0.01%. It is 2.0% or less, and the melt viscosity ratio obtained by the following formula is 2 or more in the melt viscosity measurement measured from 40° C. to 195° C. at a heating rate of 8° C./min.
Melt viscosity ratio = [Maximum melt viscosity from 40°C to 195°C (Pa s)]/[Average melt viscosity from 40°C to 100°C (Pa s)]
［断面における空隙率］
　本発明の樹脂シートの断面における空隙率は０．０１％以上２．０％以下である。空隙率が２．０％超であると、樹脂シート中の空気の割合が高くなり絶縁性が低下する。一方で、空隙率が０．０１％未満であると、樹脂シート上に金属板を積層する場合などに、樹脂が横側に流出する現象（樹脂フロー）が生じやすくなり、絶縁性が低下する。樹脂フローを抑制しやすくする観点から、樹脂シートの断面における空隙率は、好ましくは０．０５％以上、より好ましくは０．１％以上であり、絶縁性を向上させる観点から、好ましくは１．８％以下、より好ましくは１．６％以下である。
　なお、樹脂シートの断面における空隙率は、樹脂シートの断面を走査型電子顕微鏡（ＳＥＭ）で観察した際の、断面の面積に対する空隙の面積の割合を意味し、詳細には実施例に記載の方法で測定される。なお、空隙率は、後述する樹脂シートを製造する条件、具体的には硬化性樹脂組成物のプレス圧力、プレス時間、プレス温度などを調節することにより、所望の値に調整することができる。 [Porosity in cross section]
The cross-sectional porosity of the resin sheet of the present invention is 0.01% or more and 2.0% or less. If the porosity is more than 2.0%, the ratio of air in the resin sheet increases and the insulating properties deteriorate. On the other hand, if the porosity is less than 0.01%, a phenomenon in which the resin flows out to the side (resin flow) is likely to occur when a metal plate is laminated on the resin sheet, and the insulating properties deteriorate. . From the viewpoint of facilitating suppression of resin flow, the cross-sectional porosity of the resin sheet is preferably 0.05% or more, more preferably 0.1% or more. It is 8% or less, more preferably 1.6% or less.
In addition, the porosity in the cross section of the resin sheet means the ratio of the area of the voids to the area of the cross section when the cross section of the resin sheet is observed with a scanning electron microscope (SEM). measured by the method The porosity can be adjusted to a desired value by adjusting the conditions for producing the resin sheet described later, specifically the pressing pressure, pressing time, pressing temperature, etc. of the curable resin composition.
［溶融粘度比率］
　本発明の樹脂シートの溶融粘度比率は２以上である。溶融粘度比率が２未満であると、樹脂シート上に金属板を積層する際の密着性が悪くなる。密着性向上の観点から、樹脂シートの溶融粘度比率は、好ましくは４以上であり、より好ましくは６以上である。溶融粘度比率の上限は特に限定されないが、通常は、樹脂シートの溶融粘度比率は２０以下である。なお、溶融粘度比率は、後述する樹脂シートを製造する条件、具体的には硬化性樹脂組成物のプレス圧力、プレス時間、プレス温度などを調節することにより、所望の値に調整することができる。 [Melt viscosity ratio]
The melt viscosity ratio of the resin sheet of the present invention is 2 or more. If the melt viscosity ratio is less than 2, the adhesion when laminating the metal plate on the resin sheet is deteriorated. From the viewpoint of improving adhesion, the melt viscosity ratio of the resin sheet is preferably 4 or more, more preferably 6 or more. Although the upper limit of the melt viscosity ratio is not particularly limited, the melt viscosity ratio of the resin sheet is usually 20 or less. The melt viscosity ratio can be adjusted to a desired value by adjusting the conditions for producing the resin sheet described later, specifically the press pressure, press time, press temperature, etc. of the curable resin composition. .
　溶融粘度比率は、４０℃から１９５℃まで８℃／分の昇温速度で測定する溶融粘度測定において、下記式で求められる
溶融粘度比率＝［４０℃から１９５℃における最大溶融粘度（Ｐａ・ｓ）］／［４０℃から１００℃における平均溶融粘度（Ｐａ・ｓ）］
　具体的には、レオメーター測定装置（ＴＡ　ｉｎｓｔｒｕｍｅｎｔｓ社製、「ＡＲＥＳ」）を用いて、角速度４０ｒａｄ／ｓｅｃ、測定温度４０～１９５℃、８℃/分の昇温速度の条件で各温度の溶融粘度を測定し、溶融粘度比率を求める。なお、４０℃～１００℃における平均溶融粘度とは、４０℃から１００℃まで８℃／分で昇温する際の温度－溶融粘度のグラフにおける溶融粘度の平均値であり、少なくも３５０点以上の等間隔で取得した溶融粘度値の平均値を意味する。 The melt viscosity ratio is obtained by the following formula in melt viscosity measurement where the temperature is increased from 40 ° C. to 195 ° C. at a rate of 8 ° C./min. )] / [average melt viscosity from 40 ° C. to 100 ° C. (Pa s)]
Specifically, using a rheometer measuring device (manufactured by TA instruments, "ARES"), melting at each temperature under the conditions of an angular velocity of 40 rad/sec, a measurement temperature of 40 to 195 ° C., and a heating rate of 8 ° C./min. Measure the viscosity and determine the melt viscosity ratio. The average melt viscosity at 40 ° C. to 100 ° C. is the average value of the melt viscosity in the temperature-melt viscosity graph when the temperature is increased from 40 ° C. to 100 ° C. at 8 ° C./min, and is at least 350 points. Means the average value of the melt viscosity values obtained at equal intervals.
［バインダー樹脂］
　本発明の樹脂シートに含まれるバインダー樹脂は、特に限定されないが、熱硬化性樹脂が好ましくは、例えば、尿素樹脂及びメラミン樹脂等のアミノ樹脂、フェノール樹脂、熱硬化性ウレタン樹脂、エポキシ樹脂、フェノキシ樹脂、熱硬化性ポリイミド樹脂及びアミノアルキド樹脂等が挙げられる。樹脂シートに使用するバインダー樹脂は、１種単独で使用してもよいし、２種以上を併用してもよい。バインダー樹脂としては、上記した中でも、エポキシ樹脂が好ましい。 [Binder resin]
The binder resin contained in the resin sheet of the present invention is not particularly limited, but is preferably a thermosetting resin. resins, thermosetting polyimide resins, amino alkyd resins, and the like. The binder resin used for the resin sheet may be used singly or in combination of two or more. As the binder resin, epoxy resin is preferable among those mentioned above.
　エポキシ樹脂としては、例えば、分子中にエポキシ基を２つ以上含有する化合物が挙げられる。エポキシ樹脂は、例えば重量平均分子量が５０００未満となるものである。
　エポキシ樹脂としては、具体的には、スチレン骨格含有エポキシ樹脂、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ビスフェノールＳ型エポキシ樹脂、フェノールノボラック型エポキシ樹脂、ビフェノール型エポキシ樹脂、ナフタレン型エポキシ樹脂、ビフェニル型エポキシ樹脂、フルオレン型エポキシ樹脂、フェノールアラルキル型エポキシ樹脂、ナフトールアラルキル型エポキシ樹脂、ジシクロペンタジエン型エポキシ樹脂、アントラセン型エポキシ樹脂、アダマンタン骨格を有するエポキシ樹脂、トリシクロデカン骨格を有するエポキシ樹脂、及びトリアジン核を骨格に有するエポキシ樹脂、グリシジルアミン型エポキシ樹脂が挙げられる。 Epoxy resins include, for example, compounds containing two or more epoxy groups in the molecule. The epoxy resin has a weight average molecular weight of less than 5,000, for example.
Specific examples of epoxy resins include styrene skeleton-containing epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, phenol novolac-type epoxy resins, biphenol-type epoxy resins, naphthalene-type epoxy resins, biphenyl-type epoxy resins, fluorene-type epoxy resins, phenol aralkyl-type epoxy resins, naphthol aralkyl-type epoxy resins, dicyclopentadiene-type epoxy resins, anthracene-type epoxy resins, epoxy resins having an adamantane skeleton, epoxy resins having a tricyclodecane skeleton, and epoxy resins having a triazine nucleus in the skeleton, and glycidylamine type epoxy resins.
　また、エポキシ樹脂のエポキシ当量は、特に限定されないが、例えば７０ｇ／ｅｑ以上５００ｇ／ｅｑ以下である。エポキシ樹脂のエポキシ当量は、好ましくは８０ｇ／ｅｑ以上であり、そして好ましくは４００ｇ／ｅｑ以下、より好ましくは３５０ｇ／ｅｑ以下である。なお、エポキシ当量は、例えば、ＪＩＳ　Ｋ　７２３６に規定された方法に従って測定できる。
　上記したエポキシ樹脂は、１種単独で使用してもよいし、２種以上を併用してもよい。 Moreover, although the epoxy equivalent of the epoxy resin is not particularly limited, it is, for example, 70 g/eq or more and 500 g/eq or less. The epoxy equivalent of the epoxy resin is preferably 80 g/eq or more, and preferably 400 g/eq or less, more preferably 350 g/eq or less. In addition, an epoxy equivalent can be measured according to the method prescribed|regulated to JISK7236, for example.
The epoxy resins described above may be used singly or in combination of two or more.
　樹脂シートにおけるバインダー樹脂の含有量は、特に限定されないが、好ましくは１０体積％以上、より好ましくは１５体積％以上であり、そして好ましくは５０体積％以下であり、より好ましくは４０体積％以下である。バインダー樹脂の含有量がこれら下限値以上であると、硬化後において、窒化ホウ素粒子などの無機フィラーを十分に結着させて、所望の形状のシートを得ることができる。バインダー樹脂の含有量がこれら上限値以下であると、窒化ホウ素粒子などの無機フィラーを一定量以上含有させることができるので、絶縁性を良好にしつつ、熱伝導性を優れたものとすることができる。 The content of the binder resin in the resin sheet is not particularly limited, but is preferably 10% by volume or more, more preferably 15% by volume or more, and preferably 50% by volume or less, more preferably 40% by volume or less. be. When the content of the binder resin is at least these lower limits, it is possible to sufficiently bind the inorganic filler such as boron nitride particles after curing to obtain a sheet having a desired shape. If the content of the binder resin is not more than these upper limits, a certain amount or more of inorganic filler such as boron nitride particles can be contained, so that it is possible to improve thermal conductivity while improving insulation. can.
［硬化剤］
　上記した樹脂シートに含まれるバインダー樹脂は、硬化剤により硬化し、窒化ホウ素粒子などの無機フィラーを結着させることが好ましい。すなわち、本発明に係る樹脂シートは、さらに硬化剤を含むことが好ましい。
　硬化剤としては、例えば、フェノール化合物（フェノール熱硬化剤）、アミン化合物（アミン熱硬化剤）、イミダゾール化合物、酸無水物などが挙げられる。これらの中では、イミダゾール系化合物が好ましい。硬化剤は、１種単独で使用してもよいし、２種以上を併用してもよい。 [Curing agent]
It is preferable that the binder resin contained in the resin sheet is cured by a curing agent to bind inorganic fillers such as boron nitride particles. That is, the resin sheet according to the present invention preferably further contains a curing agent.
Examples of curing agents include phenol compounds (phenol heat curing agents), amine compounds (amine heat curing agents), imidazole compounds, acid anhydrides, and the like. Among these, imidazole compounds are preferred. Curing agents may be used singly or in combination of two or more.
　フェノール化合物としては、ノボラック型フェノール、ビフェノール型フェノール、ナフタレン型フェノール、ジシクロペンタジエン型フェノール、アラルキル型フェノール及びジシクロペンタジエン型フェノール等が挙げられる。
　アミン化合物としては、ジシアンジアミド、ジアミノジフェニルメタン及びジアミノジフェニルスルフォン等が挙げられる。 Examples of phenol compounds include novolac-type phenol, biphenol-type phenol, naphthalene-type phenol, dicyclopentadiene-type phenol, aralkyl-type phenol, and dicyclopentadiene-type phenol.
Amine compounds include dicyandiamide, diaminodiphenylmethane, diaminodiphenylsulfone, and the like.
　イミダゾール化合物としては、２－ウンデシルイミダゾール、２－ヘプタデシルイミダゾール、２－メチルイミダゾール、２－エチル－４－メチルイミダゾール、２－フェニルイミダゾール、２－フェニル－４－メチルイミダゾール、１－ベンジル－２－メチルイミダゾール、１－ベンジル－２－フェニルイミダゾール、１，２－ジメチルイミダゾール、１－シアノエチル－２－メチルイミダゾール、１－シアノエチル－２－エチル－４－メチルイミダゾール、１－シアノエチル－２－ウンデシルイミダゾール、１－シアノエチル－２－フェニルイミダゾール、１－シアノエチル－２－ウンデシルイミダゾリウムトリメリテイト、１－シアノエチル－２－フェニルイミダゾリウムトリメリテイト、２，４－ジアミノ－６－［２’－メチルイミダゾリル－（１’）］－エチル－ｓ－トリアジン、２，４－ジアミノ－６－［２’－ウンデシルイミダゾリル－（１’）］－エチル－ｓ－トリアジン、２，４－ジアミノ－６－［２’－エチル－４’－メチルイミダゾリル－（１’）］－エチル－ｓ－トリアジン、２，４－ジアミノ－６－［２’－メチルイミダゾリル－（１’）］－エチル－ｓ－トリアジンイソシアヌル酸付加物、２－フェニルイミダゾールイソシアヌル酸付加物、２－メチルイミダゾールイソシアヌル酸付加物、２－フェニル－４，５－ジヒドロキシメチルイミダゾール及び２－フェニル－４－メチル－５－ジヒドロキシメチルイミダゾール等が挙げられる。 Examples of imidazole compounds include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2 -methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecyl imidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'- Methylimidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6-[2′-undecylimidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6 -[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s- triazine isocyanurate, 2-phenylimidazole isocyanurate, 2-methylimidazole isocyanurate, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-dihydroxymethylimidazole, etc. is mentioned.
　酸無水物としては、スチレン／無水マレイン酸コポリマー、ベンゾフェノンテトラカルボン酸無水物、ピロメリット酸無水物、トリメリット酸無水物、４，４’－オキシジフタル酸無水物、フェニルエチニルフタル酸無水物、グリセロールビス（アンヒドロトリメリテート）モノアセテート、エチレングリコールビス（アンヒドロトリメリテート）、メチルテトラヒドロ無水フタル酸、メチルヘキサヒドロ無水フタル酸、及びトリアルキルテトラヒドロ無水フタル酸等が挙げられる。 Acid anhydrides include styrene/maleic anhydride copolymer, benzophenonetetracarboxylic anhydride, pyromellitic anhydride, trimellitic anhydride, 4,4′-oxydiphthalic anhydride, phenylethynylphthalic anhydride, glycerol. Bis(anhydrotrimellitate) monoacetate, ethylene glycol bis(anhydrotrimellitate), methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride and the like.
　硬化剤を使用する場合、バインダー樹脂に対する硬化剤の含有量は体積基準で、バインダー樹脂を適切に硬化できる限り特に限定されないが、例えば０．１以上０．８以下である。バインダー樹脂に対する硬化剤の含有量は体積基準で好ましくは０．１５以上、より好ましくは０．２以上であり、そして好ましくは０．６以下、より好ましくは０．５以下である。 When using a curing agent, the content of the curing agent relative to the binder resin is not particularly limited as long as the binder resin can be appropriately cured on a volume basis, but is, for example, 0.1 or more and 0.8 or less. The content of the curing agent to the binder resin is preferably 0.15 or more, more preferably 0.2 or more, and preferably 0.6 or less, more preferably 0.5 or less, on a volume basis.
［窒化ホウ素粒子］
　本発明の樹脂シートは、窒化ホウ素粒子を含有する。窒化ホウ素粒子を含有することにより、樹脂シートの熱伝導性及び絶縁性が向上する。
　樹脂シートにおける窒化ホウ素粒子の含有量は、３０体積％以上８０体積％以下である。窒化ホウ素粒子の含有量は３０体積未満であると、樹脂シートの熱伝導性が低下しやすくなる。一方、窒化ホウ素粒子の含有量が８０体積％超であると、バインダー樹脂の量が少なるため、所望の形状の樹脂シート及びその硬化物が得られにくくなる。
　樹脂シートにおける窒化ホウ素粒子の含有量は、好ましくは４０体積％以上、より好ましくは５０体積％以上であり、そして好ましくは７５体積％以下であり、より好ましくは７０体積％以下である。 [Boron nitride particles]
The resin sheet of the present invention contains boron nitride particles. By containing boron nitride particles, the thermal conductivity and insulating properties of the resin sheet are improved.
The content of the boron nitride particles in the resin sheet is 30% by volume or more and 80% by volume or less. When the content of the boron nitride particles is less than 30 volumes, the thermal conductivity of the resin sheet tends to decrease. On the other hand, if the content of the boron nitride particles exceeds 80% by volume, the amount of the binder resin is so small that it becomes difficult to obtain a desired shape of the resin sheet and its cured product.
The content of boron nitride particles in the resin sheet is preferably 40% by volume or more, more preferably 50% by volume or more, and preferably 75% by volume or less, more preferably 70% by volume or less.
　窒化ホウ素粒子の一次粒子の平均長径は、特に限定されないが、好ましくは１μｍ以上、より好ましくは１．５μｍ以上、さらに好ましくは２．０μｍ以上であり、そして好ましくは２０μｍ以下であり、より好ましくは１５μｍ以下であり、さらに好ましくは１０μｍ以下である。
　窒化ホウ素粒子の一次粒子の長径と短径により求められる平均アスペクト比は、好ましくは１以上、より好ましくは２以上であり、そして好ましくは７以下、より好ましくは６以下である。
　平均アスペクト比及び平均長径は、クロスセクションポリッシャーにより表出させた断面において測定した、窒化ホウ素粒子の一次粒子径の長径と短径により求める。具体的には以下のとおりである。
　まず、クロスセクションポリッシャーにより、樹脂シートの硬化物の断面を表出させ、その表出した断面を走査電子顕微鏡（ＳＥＭ）で４００～１２００倍に観察し、観察画像を得る。その観察画像において、画像解析ソフトを用いて、無作為に２００個の窒化ホウ素粒子の一次粒子について長径及び短径を測定して、長径／短径により各粒子のアスペクト比を算出し、その２００個の平均値を平均アスペクトとする。また、測定した２００個の一次粒子の長径の平均値を平均長径とする。なお、長径とは、観察画像において、観察される窒化ホウ素粒子の一次粒子の最も長い部分の長さである。また、短径とは、観察画像において、長径方向に対して垂直な方向における長さである。 The average length of the primary particles of the boron nitride particles is not particularly limited, but is preferably 1 μm or more, more preferably 1.5 μm or more, still more preferably 2.0 μm or more, and more preferably 20 μm or less, and more preferably It is 15 μm or less, more preferably 10 μm or less.
The average aspect ratio determined by the major axis and minor axis of the primary particles of boron nitride particles is preferably 1 or more, more preferably 2 or more, and preferably 7 or less, more preferably 6 or less.
The average aspect ratio and average major axis are obtained from the major axis and minor axis of the primary particle diameter of the boron nitride particles measured in the cross section exposed by the cross-section polisher. Specifically, it is as follows.
First, a cross-section of the cured resin sheet is exposed by a cross-section polisher, and the exposed cross-section is observed with a scanning electron microscope (SEM) at a magnification of 400 to 1200 to obtain an observed image. In the observation image, using image analysis software, the major diameter and minor diameter of the primary particles of 200 boron nitride particles are randomly measured, and the aspect ratio of each particle is calculated from the major diameter / minor diameter. Let the average value of 1 be the average aspect. Also, the average value of the major diameters of the measured 200 primary particles is defined as the average major diameter. The major diameter is the length of the longest portion of the observed primary particles of the boron nitride particles in the observation image. Also, the minor axis is the length in the direction perpendicular to the major axis direction in the observed image.
　窒化ホウ素粒子は、窒化ホウ素凝集粒子を含むことが好ましい。窒化ホウ素凝集粒子は、一次粒子を凝集して構成される凝集粒子である。
　窒化ホウ素凝集粒子は、一般的に、例えばＳＥＭによる断面観察により、凝集粒子か否かを判別できる。なお、窒化ホウ素凝集粒子は、プレス成形などの種々の工程を経ることで、凝集粒子の形態を維持することもあるし、変形、崩壊、解砕などすることがある。ただし、窒化ホウ素凝集粒子は、バインダー樹脂と混合後に、プレス成形などの工程を経ることで、仮に変形、崩壊、解砕などしても概ね配向せず、また、ある程度の纏まりとなって存在するため、例えば上記した断面を観察することにより、窒化ホウ素凝集粒子であることが示唆され、それにより凝集粒子か否かを判別できる。 The boron nitride particles preferably comprise boron nitride agglomerate particles. Agglomerated boron nitride particles are aggregated particles formed by aggregating primary particles.
Boron nitride agglomerated particles can generally be determined whether they are agglomerated particles, for example, by cross-sectional observation with an SEM. The aggregated boron nitride particles may maintain the shape of the aggregated particles, or may be deformed, disintegrated, or crushed through various processes such as press molding. However, after being mixed with a binder resin, the aggregated boron nitride particles are subjected to a process such as press molding, so that even if they are deformed, collapsed, crushed, etc., they are generally not oriented, and they exist in a certain amount of aggregation. Therefore, for example, by observing the cross section described above, it is suggested that the particles are boron nitride agglomerated particles, and it can be determined whether or not they are agglomerated particles.
　樹脂シートに配合される窒化ホウ素凝集粒子は、絶縁性と熱伝導性とを効果的に高める観点から、平均粒子径が５μｍ以上であることが好ましく、１０μｍ以上であることがより好ましく、また、２００μｍ以下であることが好ましく、１５０μｍ以下であることがより好ましく、１００μｍ以下であることがさらに好ましい。
　凝集粒子の平均粒子径は、レーザー回折・散乱法で測定できる。平均粒子径の算出方法については、累積体積が５０％であるときの凝集粒子の粒子径（ｄ５０）を平均粒子径として採用する。 The aggregated boron nitride particles mixed in the resin sheet preferably have an average particle size of 5 μm or more, more preferably 10 μm or more, from the viewpoint of effectively improving insulation and thermal conductivity. It is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less.
The average particle size of aggregated particles can be measured by a laser diffraction/scattering method. Regarding the method of calculating the average particle size, the particle size (d50) of aggregated particles when the cumulative volume is 50% is adopted as the average particle size.
　窒化ホウ素凝集粒子の製造方法は、特に限定されず、公知の方法で製造できる。例えば、予め用意した一次粒子を凝集（造粒）させて得ることができ、具体的には、噴霧乾燥方法及び流動層造粒方法等が挙げられる。噴霧乾燥方法（スプレードライとも呼ばれる）は、スプレー方式によって、二流体ノズル方式、ディスク方式（ロータリ方式とも呼ばれる）、及び超音波ノズル方式等に分類でき、これらのどの方式でも適用できる。
　また、窒化ホウ素凝集粒子の製造方法としては、必ずしも造粒工程は必要ではない。例えば、公知の方法で結晶化させた窒化ホウ素の結晶の成長に伴い、窒化ホウ素の一次粒子が自然に集結することで凝集粒子を形成させてもよい。
　また、窒化ホウ素凝集粒子としては、例えば、昭和電工株式会社製の「ＵＨＰ－Ｇ１Ｈ」、水島合金鉄株式会社製の「ＨＰ－４０」などが挙げられる。 The method for producing the aggregated boron nitride particles is not particularly limited, and can be produced by a known method. For example, it can be obtained by aggregating (granulating) primary particles prepared in advance, and specific examples thereof include a spray drying method and a fluid bed granulation method. The spray drying method (also called spray drying) can be classified into a two-fluid nozzle method, a disk method (also called a rotary method), an ultrasonic nozzle method, etc., and any of these methods can be applied.
Moreover, the granulation step is not necessarily required as a method for producing aggregated boron nitride particles. For example, as boron nitride crystals crystallized by a known method grow, the primary particles of boron nitride naturally aggregate to form agglomerated particles.
Examples of aggregated boron nitride particles include “UHP-G1H” manufactured by Showa Denko KK, “HP-40” manufactured by Mizushima Ferroalloy Co., Ltd., and the like.
[窒化ホウ素粒子以外の無機フィラー]
　本発明の樹脂シートは、上記した窒化ホウ素粒子に加えて、窒化ホウ素粒子以外の無機フィラーを含有してもよい。窒化ホウ素粒子以外の無機フィラーとしては、熱伝導性フィラーを使用すればよい。熱伝導性フィラーは、例えば熱伝導率が１０Ｗ／（ｍ・Ｋ）以上であり、好ましくは１５Ｗ／（ｍ・Ｋ）以上、より好ましくは２０Ｗ／（ｍ・Ｋ）以上である。また、熱伝導性フィラーの熱伝導率の上限は特に限定されないが、例えば、３００Ｗ／（ｍ・Ｋ）以下でもよいし、２００Ｗ／（ｍ・Ｋ）以下でもよい。窒化ホウ素粒子以外の無機フィラーは、例えば窒化ホウ素凝集粒子などの窒化ホウ素粒子の間の隙間に入り込んで、熱伝導性をより一層高めることができる。
　なお、無機フィラーの熱伝導率は、例えば、クロスセクションポリッシャーにて切削加工したフィラー断面に対して、株式会社ベテル製サーマルマイクロスコープを用いて、周期加熱サーモリフレクタンス法により測定することができる。 [Inorganic filler other than boron nitride particles]
The resin sheet of the present invention may contain an inorganic filler other than the boron nitride particles in addition to the boron nitride particles described above. As an inorganic filler other than boron nitride particles, a thermally conductive filler may be used. The thermally conductive filler has, for example, a thermal conductivity of 10 W/(m·K) or more, preferably 15 W/(m·K) or more, more preferably 20 W/(m·K) or more. Moreover, although the upper limit of the thermal conductivity of the thermally conductive filler is not particularly limited, it may be, for example, 300 W/(m·K) or less, or 200 W/(m·K) or less. Inorganic fillers other than boron nitride particles can enter the gaps between boron nitride particles, such as boron nitride agglomerated particles, to further increase thermal conductivity.
The thermal conductivity of the inorganic filler can be measured, for example, by a periodic heating thermoreflectance method using a thermal microscope manufactured by Bethel Co., Ltd. on a cross section of the filler cut by a cross section polisher.
　窒化ホウ素粒子以外の無機フィラーとしては、好ましくはアルミナ、窒化アルミニウム、酸化マグネシウム、ダイヤモンド、及び炭化ケイ素からなる群から選択される少なくとも１種である。これら無機フィラーを使用することで、熱伝導性をより一層良好に維持しつつ、絶縁性が低下するのを防止し、かつ金属板に対する密着性も向上しやすくなる。熱伝導性及び金属板に対する密着性をより一層高い水準にしつつ、絶縁性の低下を防止する観点から、上記した中ではアルミナが好ましい。
　また、窒化ホウ素粒子以外の無機フィラーとしては、１種単独で使用してもよいし、２種以上を併用してもよい。 The inorganic filler other than boron nitride particles is preferably at least one selected from the group consisting of alumina, aluminum nitride, magnesium oxide, diamond, and silicon carbide. By using these inorganic fillers, it is possible to prevent the deterioration of the insulating property while maintaining the thermal conductivity even better, and to easily improve the adhesion to the metal plate. Alumina is preferable among the above from the viewpoint of preventing deterioration of insulating properties while improving thermal conductivity and adhesion to a metal plate.
Moreover, as inorganic fillers other than boron nitride particles, one type may be used alone, or two or more types may be used in combination.
　窒化ホウ素粒子以外の無機フィラーは、いかなる形状のフィラーを使用してもよく、鱗片状、球状、破砕状、不定形状、多角形状などのいずれでもよいし、凝集粒子などでもよい。ただし、窒化ホウ素粒子以外の無機フィラーとしては、一次粒子の平均アスペクト比が３以下であることが好ましい。そのようなフィラーとして、球状フィラーなどが挙げられる。球状フィラーとしては、球状アルミナがより好ましい。なお、一次粒子の平均アスペクト比は上記のとおり断面観察により測定できる。
　窒化ホウ素粒子以外の無機フィラーの平均アスペクト比は、より好ましくは２以下である。窒化ホウ素粒子以外の無機フィラーのアスペクト比は、１以上であればよい。このようにアスペクト比が低い窒化ホウ素粒子以外の無機フィラーを使用すると、熱伝導性や金属板に対する密着性を高めやすくなる。 The inorganic filler other than the boron nitride particles may be of any shape, and may be scaly, spherical, crushed, amorphous, polygonal, or aggregated particles. However, the inorganic filler other than the boron nitride particles preferably has an average aspect ratio of primary particles of 3 or less. Examples of such fillers include spherical fillers. Spherical alumina is more preferable as the spherical filler. The average aspect ratio of primary particles can be measured by cross-sectional observation as described above.
The average aspect ratio of inorganic fillers other than boron nitride particles is more preferably 2 or less. The inorganic filler other than boron nitride particles may have an aspect ratio of 1 or more. The use of inorganic fillers other than boron nitride particles having such a low aspect ratio makes it easier to improve thermal conductivity and adhesion to metal plates.
　窒化ホウ素粒子以外の無機フィラーの平均粒子径は、０．１μｍ以上であることが好ましく、０．２μｍ以上であることがより好ましく、０．３μｍ以上であることがさらに好ましい。また、１００μｍ以下であることが好ましく、８０μｍ以下であることがより好ましく、７０μｍ以下であることがさらに好ましい。平均粒子径をこれら上限値以下とすると、無機フィラーを樹脂シートに高充填で配合しやすくなる。また、下限値以上とすると、絶縁性を高めやすくなる。窒化ホウ素粒子以外の無機フィラーの平均粒子径は、例えばコールターカウンター法で測定できる。
　窒化ホウ素粒子以外の無機フィラーは、１種単独で使用してもよいし、２種以上を併用してもよい。 The average particle size of the inorganic filler other than the boron nitride particles is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more. Also, it is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 70 μm or less. When the average particle size is less than these upper limits, it becomes easier to mix the inorganic filler in the resin sheet at a high filling rate. Moreover, when it is more than a lower limit, it will become easy to improve insulation. The average particle size of inorganic fillers other than boron nitride particles can be measured, for example, by the Coulter Counter method.
Inorganic fillers other than boron nitride particles may be used singly or in combination of two or more.
　樹脂シートにおける窒化ホウ素粒子以外の無機フィラーの含有量は、例えば２体積％以上５５体積％以下である。このような含有量に調整することにより、例えば、熱伝導性や金属板に対する密着性をより一層高めることできる。樹脂シートにおける窒化ホウ素粒子以外の無機フィラーの含有量は、好ましくは４体積％以上、より好ましくは１０体積％以上であり、また、窒化ホウ素粒子以外の無機フィラーの含有量は、好ましくは５５体積％以下であり、窒化ホウ素粒子を一定量以上含有させて熱伝導性を担保しやすくなる観点から、４５体積％以下がより好ましい。 The content of inorganic fillers other than boron nitride particles in the resin sheet is, for example, 2% by volume or more and 55% by volume or less. By adjusting the content to such a value, for example, thermal conductivity and adhesion to the metal plate can be further enhanced. The content of inorganic fillers other than boron nitride particles in the resin sheet is preferably 4% by volume or more, more preferably 10% by volume or more, and the content of inorganic fillers other than boron nitride particles is preferably 55% by volume. %, and more preferably 45% by volume or less from the viewpoint of making it easier to ensure thermal conductivity by containing a certain amount or more of boron nitride particles.
　窒化ホウ素粒子以外の無機フィラーを含む場合、窒化ホウ素粒子に対する、窒化ホウ素粒子以外の無機フィラーの体積基準での比率（窒化ホウ素粒子以外の無機フィラー／窒化ホウ素粒子）は、例えば０．００５以上４以下である。この範囲内とすることで、熱伝導性や金属板に対する密着性をより一層高めつつ、加熱による絶縁性の低下を抑制しやすくなる。そのような観点から、上記比率は、好ましく０．０１以上、より好ましくは０．１以上、さらに好ましくは０．３以上であり、また、好ましくは３以下、より好ましくは２以下、さらに好ましくは１以下である。 When an inorganic filler other than boron nitride particles is included, the volume ratio of the inorganic filler other than boron nitride particles to the boron nitride particles (inorganic filler other than boron nitride particles/boron nitride particles) is, for example, 0.005 or more 4 It is below. By setting it within this range, it becomes easier to suppress the deterioration of the insulation due to heating while further increasing the thermal conductivity and the adhesion to the metal plate. From such a viewpoint, the ratio is preferably 0.01 or more, more preferably 0.1 or more, still more preferably 0.3 or more, and preferably 3 or less, more preferably 2 or less, and further preferably 1 or less.
　樹脂シートにおける窒化ホウ素粒子と前記窒化ホウ素粒子以外の無機フィラーとの合計の含有量は、好ましくは６５体積％以上である。６５体積以上であると、より一層高い放熱性能を確保することができる。
　また、樹脂シートにおける窒化ホウ素粒子と前記窒化ホウ素粒子以外の無機フィラーとの合計の含有量は、好ましくは８０体積％以下である。８０体積％以下とすることで、樹脂シートの金属板に対する密着性がより一層良好となる。そのような観点から、無機フィラーの含有量は、７８体積％以下が好ましく、７５体積％以下がより好ましく、７０体積％以下がさらに好ましい。 The total content of the boron nitride particles and the inorganic filler other than the boron nitride particles in the resin sheet is preferably 65% by volume or more. When it is 65 volumes or more, it is possible to ensure even higher heat dissipation performance.
Further, the total content of the boron nitride particles and the inorganic filler other than the boron nitride particles in the resin sheet is preferably 80% by volume or less. By making it 80% by volume or less, the adhesion of the resin sheet to the metal plate is further improved. From such a viewpoint, the content of the inorganic filler is preferably 78% by volume or less, more preferably 75% by volume or less, and even more preferably 70% by volume or less.
［その他］
　本発明に係る樹脂シートは、上記成分以外にも、分散剤、硬化促進剤、シランカップリング剤などのカップリング剤、難燃剤、酸化防止剤、イオン捕捉剤、粘着性付与剤、可塑剤、チソ性付与剤、及び着色剤などのその他の添加剤を含んでいてもよい。 [others]
In addition to the above components, the resin sheet according to the present invention contains a dispersant, a curing accelerator, a coupling agent such as a silane coupling agent, a flame retardant, an antioxidant, an ion scavenger, a tackifier, a plasticizer, Other additives such as thiso-imparting agents and colorants may also be included.
［厚み］
　本発明の樹脂シートの厚みは、特に限定されないが、例えば５０μｍ以上５００μｍ以下である。厚みが５０μｍ以上であると、一定の絶縁性、放熱性を確保しやすくなり、厚みが５００μｍ以下であると、後述する回路基板や半導体装置などを薄膜化しやすくなる。絶縁樹脂シートの厚みは、好ましくは６０μｍ以上、より好ましくは７０μｍ以上であり、そして好ましくは４００μｍ以下であり、より好ましくは２００μｍ以下である。 [Thickness]
Although the thickness of the resin sheet of the present invention is not particularly limited, it is, for example, 50 μm or more and 500 μm or less. When the thickness is 50 μm or more, it becomes easy to secure a certain level of insulation and heat dissipation, and when the thickness is 500 μm or less, it becomes easy to thin a circuit board or a semiconductor device, which will be described later. The thickness of the insulating resin sheet is preferably 60 μm or more, more preferably 70 μm or more, and preferably 400 μm or less, more preferably 200 μm or less.
[樹脂シートの製造方法]
　本発明の樹脂シートは、バインダー樹脂、窒化ホウ素粒子、並びに必要に応じて配合される窒化ホウ素粒子以外の無機フィラー、硬化剤、及びその他の添加剤を含有する硬化性樹脂組成物により形成される。硬化性樹脂組成物により樹脂シートを形成する方法は、特に制限されないが、例えば、硬化性樹脂組成物を剥離シートなどの支持体上に塗布して乾燥させた塗膜を、所定の条件で熱プレスをするとよい。硬化性樹脂組成物は、希釈溶媒により希釈したうえで、支持体上などに塗布し、乾燥してもよい。
　熱プレスの条件は、バインダー樹脂の種類、窒化ホウ素粒子の含有量などに応じて、所定の溶融粘度比率及びボイド率となるように適宜調整すればよく、限定されるものではないが、例えば次の通り調整するとよい。プレス圧力を例えば５ＭＰａ以上３０ＭＰａ以下、好ましくは１５ＭＰａ以上２５ＭＰａ以下、プレス温度を例えば６０℃以上１３０℃以下、好ましくは７０℃以上１１０℃以下、プレス時間を例えば２０分以上１２０分以下、好ましくは３０分以上１００分以下とすればよい。熱プレスを行い形成された樹脂シートに含まれるバインダー樹脂は、未硬化の状態であるか、一部が硬化された状態となる。なお、上記一部が硬化された状態について、本明細書においては半硬化状態ともいう。 [Resin sheet manufacturing method]
The resin sheet of the present invention is formed of a curable resin composition containing a binder resin, boron nitride particles, and optionally an inorganic filler other than the boron nitride particles, a curing agent, and other additives. . The method of forming the resin sheet from the curable resin composition is not particularly limited, but for example, the curable resin composition is coated on a support such as a release sheet, and the dried coating is heated under predetermined conditions. press. The curable resin composition may be diluted with a diluting solvent, applied to a support or the like, and dried.
The conditions for hot pressing may be appropriately adjusted according to the type of binder resin, the content of boron nitride particles, etc., so as to achieve a predetermined melt viscosity ratio and void ratio, and are not limited, but for example the following: should be adjusted as follows. The press pressure is, for example, 5 MPa or more and 30 MPa or less, preferably 15 MPa or more and 25 MPa or less, the press temperature is, for example, 60° C. or more and 130° C. or less, preferably 70° C. or more and 110° C. or less, and the press time is, for example, 20 minutes or more and 120 minutes or less, preferably 30 minutes. minutes or more and 100 minutes or less. The binder resin contained in the resin sheet formed by hot pressing is in an uncured state or in a partially cured state. In this specification, the partially cured state is also referred to as a semi-cured state.
　熱プレスの具体的な方法は特に限定されないが、製造上の歩留まり向上の観点などから以下の方法が好ましい。最初に、剥離シート（例えば離型ＰＥＴシート）などの支持体上に硬化性樹脂組成物を塗布し乾燥して塗膜を形成させた試料（支持体上に塗膜が形成されている試料）を２つ用意して、該２つの試料を塗膜同士が接触するように積層した積層物を用意する。そして、該積層物の両面を２枚の金属板で挟んで熱プレスをする。このような方法により製造された樹脂シートは、２層構造となるため、ピンホールが形成された樹脂シートが製造される頻度を低減することができる。 The specific method of hot pressing is not particularly limited, but the following method is preferable from the viewpoint of improving the manufacturing yield. First, a sample in which a curable resin composition is applied onto a support such as a release sheet (e.g., a release PET sheet) and dried to form a coating film (a sample having a coating film formed on the support) are prepared, and a laminate is prepared by laminating the two samples so that the coating films are in contact with each other. Both surfaces of the laminate are sandwiched between two metal plates and hot-pressed. Since the resin sheet manufactured by such a method has a two-layer structure, it is possible to reduce the frequency of manufacturing a resin sheet having pinholes formed therein.
[樹脂シートの硬化物]
　本発明における樹脂シートは、バインダー樹脂の硬化温度以上の温度で加熱することにより硬化させ、樹脂シートの硬化物とすることができる。硬化は、加圧下で加熱して行うことが好ましい。樹脂シートの硬化物は、後述する積層体の一部を構成することができる。
　樹脂シートの硬化物の熱伝導率は、好ましくは１０Ｗ／(ｍ・Ｋ）以上である。熱伝導率を１０Ｗ／（ｍ・Ｋ）以上とすることで、放熱性能が優れたものとなり、回路基板として使用した場合に、回路基板上に実装される素子で生じた熱を効率的に外部に逃がすことができる。そのため、例えば、バワーモジュールで使用されるパワー素子など、放熱量の多い素子を実装しても素子の温度が高くなりすぎることを防止できる。樹脂シートの硬化物の熱伝導率は、より好ましくは１１Ｗ／（ｍ・Ｋ）以上、さらに好ましくは１２Ｗ／（ｍ・Ｋ）以上、よりさらに好ましくは１５Ｗ／（ｍ・Ｋ）以上である。また、樹脂シートの硬化物の熱伝導率の上限は、特に限定されないが、実用的には例えば３０Ｗ／（ｍ・Ｋ）程度である。なお、樹脂シートの硬化物の熱伝導率は、レーザーフラッシュ法により厚み方向の熱伝導率を測定するとよい。 [Cured product of resin sheet]
The resin sheet in the present invention can be cured by heating at a temperature equal to or higher than the curing temperature of the binder resin to obtain a cured product of the resin sheet. Curing is preferably carried out by heating under pressure. A cured product of the resin sheet can constitute a part of a laminate to be described later.
The thermal conductivity of the cured resin sheet is preferably 10 W/(m·K) or more. By setting the thermal conductivity to 10 W/(m·K) or more, the heat radiation performance is excellent, and when used as a circuit board, the heat generated by the elements mounted on the circuit board is efficiently released to the outside. can escape to Therefore, for example, even if a power element used in a power module or the like that dissipates a large amount of heat is mounted, it is possible to prevent the temperature of the element from becoming too high. The thermal conductivity of the cured resin sheet is more preferably 11 W/(m·K) or higher, still more preferably 12 W/(m·K) or higher, and even more preferably 15 W/(m·K) or higher. The upper limit of the thermal conductivity of the cured resin sheet is not particularly limited, but is practically about 30 W/(m·K), for example. As for the thermal conductivity of the cured product of the resin sheet, it is preferable to measure the thermal conductivity in the thickness direction by a laser flash method.
［積層体］
　本発明の積層体は、図１に示すように、本発明の樹脂シートの硬化物１０に加えて、金属ベース板１１及び金属板１２を備え、金属ベース板１１上に、樹脂シートの硬化物１０及び金属板１２をこの順に備える積層体１３である。 [Laminate]
As shown in FIG. 1, the laminate of the present invention comprises a metal base plate 11 and a metal plate 12 in addition to the cured resin sheet 10 of the present invention. 10 and a metal plate 12 in this order.
　金属ベース板１１及び金属板１２は、それぞれ熱伝導体としての機能を発揮するため、その熱伝導率は、１０Ｗ／ｍ・Ｋ以上であることが好ましい。これらに用いる材料としては、アルミニウム、銅、金、銀などの金属、及びグラファイトシート等が挙げられる。熱伝導性をより一層効果的に高める観点からは、アルミニウム、銅、又は金であることが好ましく、アルミニウム又は銅であることがより好ましい。
　金属ベース板１１の厚みは、０．１～５ｍｍであることが好ましく、金属板１２の厚みは、１０～２０００μｍであることが好ましく、１０～９００μｍであることがより好ましい。なお、金属板としては、銅板のような板や銅箔のような箔の場合も含む。 Since the metal base plate 11 and the metal plate 12 function as heat conductors, the heat conductivity thereof is preferably 10 W/m·K or more. Materials used for these include metals such as aluminum, copper, gold, and silver, and graphite sheets. Aluminum, copper, or gold is preferred, and aluminum or copper is more preferred, from the viewpoint of more effectively increasing thermal conductivity.
The thickness of the metal base plate 11 is preferably 0.1-5 mm, and the thickness of the metal plate 12 is preferably 10-2000 μm, more preferably 10-900 μm. The metal plate includes a plate such as a copper plate and a foil such as copper foil.
　金属ベース板の形状は特に限定されないが、平板状であってもよく、凹凸状、蛇腹状などの表面積が大きくなる形状であってもよい。 The shape of the metal base plate is not particularly limited, but it may be a flat plate shape, or a shape with a large surface area such as an uneven shape or a bellows shape.
　積層体１３は、回路基板として使用されることが好ましい。回路基板として使用される場合、積層体１３における金属板１２は、回路パターンを有するよい。回路パターンは、回路基板上に実装される素子などに応じて、適宜パターニングすればよい。回路パターンは、特に限定されないが、エッチングなどにより形成されるとよい。また、回路基板において、金属ベース板１１は、放熱板などとして使用される。 The laminate 13 is preferably used as a circuit board. When used as a circuit board, the metal plate 12 in the laminate 13 may have a circuit pattern. The circuit pattern may be appropriately patterned according to the elements to be mounted on the circuit board. The circuit pattern is not particularly limited, but may be formed by etching or the like. Moreover, in the circuit board, the metal base plate 11 is used as a heat sink or the like.
［半導体装置］
　本発明は、上記積層体を有する半導体装置も提供する。具体的には、図２に示すように、半導体装置１５は、樹脂シートの硬化物１０、金属ベース板１１及び金属板１２を有する積層体１３と、積層体１３の金属板１２の上に設けられる半導体素子１４とを備える。金属板１２は、エッチングなどによりパターニングされ、回路パターンを有するとよい。 [Semiconductor device]
The present invention also provides a semiconductor device having the laminate described above. Specifically, as shown in FIG. 2, a semiconductor device 15 includes a laminate 13 having a cured resin sheet 10, a metal base plate 11, and a metal plate 12, and a semiconductor device 15 provided on the metal plate 12 of the laminate 13. and a semiconductor element 14 formed by a semiconductor device. The metal plate 12 is preferably patterned by etching or the like to have a circuit pattern.
　なお、半導体素子１４は、図２では２つ示されるが、半導体素子１４の数は限定されず、１つ以上であればいくつであってもよい。また、金属板１２の上には、半導体素子１４以外にも、トランジスタ等の他の電子部品（図示しない）が搭載されていてもよい。各半導体素子１４は、金属板１２の上に形成された接続導電部１６を介して金属板１２に接続される。接続導電部１６は、はんだにより形成されるとよい。また、積層体１３の金属板１２側の表面には封止樹脂１９が設けられる。そして、少なくとも半導体素子１４が封止樹脂１９により封止され、必要に応じて、金属板１２も半導体素子１４と共に封止樹脂１９により封止されるとよい。
　半導体素子１４は、特に限定されないが、少なくとも１つがパワー素子（すなわち、電力用半導体素子）であることが好ましく、それにより、半導体装置１５がパワーモジュールであることが好ましい。パワーモジュールは、例えば、インバータなどに使用される。
　また、パワーモジュールは、例えば、エレベータ、無停電電源装置（ＵＰＳ)等の産業用機器において使用されるが、その用途は特に限定されない。 Although two semiconductor elements 14 are shown in FIG. 2, the number of semiconductor elements 14 is not limited, and may be any number as long as it is one or more. Further, other electronic components (not shown) such as transistors may be mounted on the metal plate 12 in addition to the semiconductor element 14 . Each semiconductor element 14 is connected to the metal plate 12 via a connection conductive portion 16 formed on the metal plate 12 . The connection conductive portion 16 is preferably made of solder. A sealing resin 19 is provided on the surface of the laminate 13 on the metal plate 12 side. At least the semiconductor element 14 is sealed with the sealing resin 19 , and the metal plate 12 is preferably sealed together with the semiconductor element 14 with the sealing resin 19 as necessary.
The semiconductor elements 14 are not particularly limited, but at least one is preferably a power element (that is, a power semiconductor element), so that the semiconductor device 15 is preferably a power module. Power modules are used, for example, in inverters and the like.
Moreover, the power module is used in industrial equipment such as elevators and uninterruptible power supplies (UPS), but the application is not particularly limited.
　金属板１２には、リード２０が接続されている。リード２０は、例えば封止樹脂１９より外部に延出し、金属板１２を外部機器などに接続する。また、半導体素子１４にはワイヤ１７が接続されてもよい。ワイヤ１７は、図２に示すように半導体素子１４を別の半導体素子１４、金属板１２、リード２０などに接続するとよい。
　半導体素子１４は、リード２０などを介して電力が供給されて駆動すると発熱するが、半導体素子１４で発生した熱は、樹脂シートの硬化物１０を介して金属ベース板１１に伝播され、金属ベース板１１から放熱される。金属ベース板１１は、必要に応じて放熱フィンなどからなるヒートシンクに接続されるとよい。 A lead 20 is connected to the metal plate 12 . The lead 20 extends outside, for example, from the sealing resin 19 and connects the metal plate 12 to an external device or the like. Also, a wire 17 may be connected to the semiconductor element 14 . The wires 17 may connect the semiconductor element 14 to another semiconductor element 14, the metal plate 12, the leads 20, etc., as shown in FIG.
The semiconductor element 14 generates heat when it is driven by being supplied with electric power through the leads 20 or the like. Heat is radiated from the plate 11 . The metal base plate 11 may be connected to a heat sink made up of radiation fins or the like, if necessary.
　半導体装置１５は、その製造工程において、リフロー工程を経て製造されるとよい。具体的には、半導体装置１５の製造方法においては、まず、積層体１３を用意して、積層体１３の金属板１２上にはんだ印刷などにより接続導電部１６を形成し、その接続導電部１６の上に半導体素子１４を搭載する。その後、半導体素子１４を搭載した積層体１３をリフロー炉の内部を通過させて、リフロー炉の内部で加熱し、接続導電部１６により半導体素子１４を金属板１２の上に接続させる。なお、リフロー炉内の温度は、特に限定されないが、例えば２００～３００℃程度である。半導体装置１５の製造方法においては、リフロー工程後に封止樹脂１９を積層体１３上に積層して半導体素子１４は封止すればよい。また、封止樹脂１９で封止する前に、適宜、ワイヤ１７、リード２０などを取り付けるとよい。
　なお、以上では、リフロー工程により半導体素子１４を金属板１２に接続させる態様を示したが、このような態様に限定されず、例えば、リフロー工程により、積層体１３（すなわち、回路基板）を別の基板（図示しない）に接続してもよい。 The semiconductor device 15 is preferably manufactured through a reflow process in its manufacturing process. Specifically, in the manufacturing method of the semiconductor device 15, first, the laminate 13 is prepared, the connection conductive portion 16 is formed on the metal plate 12 of the laminate 13 by solder printing or the like, and the connection conductive portion 16 is formed. A semiconductor element 14 is mounted on the . After that, the laminate 13 with the semiconductor element 14 mounted thereon is passed through a reflow furnace and heated inside the reflow furnace, and the semiconductor element 14 is connected onto the metal plate 12 by the connecting conductive portions 16 . Although the temperature in the reflow furnace is not particularly limited, it is, for example, about 200 to 300.degree. In the method of manufacturing the semiconductor device 15, the semiconductor element 14 may be sealed by laminating the sealing resin 19 on the laminate 13 after the reflow process. Also, before sealing with the sealing resin 19, the wires 17, the leads 20, etc. may be appropriately attached.
In the above description, a mode in which the semiconductor element 14 is connected to the metal plate 12 by the reflow process is shown, but the present invention is not limited to this mode. substrate (not shown).
[積層体の製造方法]
　樹脂シートの硬化物、金属ベース板、及び金属板を備える積層体を製造する場合には、樹脂シートを、金属ベース板と金属板の間に配置して、プレス成形により加熱及び加圧して、金属ベース板と金属板を、樹脂シートの硬化物を介して接着させることで積層体を製造するとよい。樹脂シートは、プレス成形時の加熱により硬化させることが好ましいが、プレス成形前に部分的又は完全に硬化させておいてもよい。 [Laminate manufacturing method]
In the case of producing a laminate comprising a cured resin sheet, a metal base plate, and a metal plate, the resin sheet is placed between the metal base plate and the metal plate, and is heated and pressed by press molding to form the metal base. It is preferable to manufacture a laminate by bonding a plate and a metal plate via a cured resin sheet. The resin sheet is preferably cured by heating during press molding, but may be partially or completely cured before press molding.
　樹脂シートの硬化物、金属ベース板、及び金属板を備え、前記金属ベース板上に、前記樹脂シートの硬化物と前記金属板をこの順に備える積層体を製造する場合は、以下に説明する各工程を含む方法が好ましい。
　バインダー樹脂及び窒化ホウ素粒子を含有する硬化性樹脂組成物を加熱及び加圧することにより半硬化状態の樹脂シートを作製する第１の熱プレス工程。
　上記半硬化状態の樹脂シートを、上記金属ベース板と上記金属板の間に配置する積層工程。
　上記積層工程で積層された半硬化状態の樹脂シートを加熱及び加圧することにより本硬化させ積層体を得る第２の熱プレス工程。
　上記半硬化状態の樹脂シートの断面における空隙率が０．０１％以上２．０％以下であり、４０℃から１９５℃まで８℃／分の昇温速度で測定する溶融粘度測定において、下記式で求められる上記半硬化状態の樹脂シートの溶融粘度比率が２以上である。
溶融粘度比率＝［４０℃から１９５℃における最大溶融粘度（Ｐａ・ｓ）］／［４０℃から１００℃における平均溶融粘度（Ｐａ・ｓ）］ When producing a laminate comprising a cured resin sheet, a metal base plate, and a metal plate, and having the cured resin sheet and the metal plate on the metal base plate in this order, each of the following A method comprising steps is preferred.
A first hot press step of producing a semi-cured resin sheet by heating and pressing a curable resin composition containing a binder resin and boron nitride particles.
A laminating step of disposing the semi-cured resin sheet between the metal base plate and the metal plate.
A second hot pressing step of heating and pressing the semi-cured resin sheets laminated in the lamination step to fully cure the resin sheets to obtain a laminate.
The porosity in the cross section of the semi-cured resin sheet is 0.01% or more and 2.0% or less, and the melt viscosity is measured from 40 ° C. to 195 ° C. at a temperature increase rate of 8 ° C./min. The melt viscosity ratio of the resin sheet in the semi-cured state obtained by is 2 or more.
Melt viscosity ratio = [Maximum melt viscosity from 40°C to 195°C (Pa s)]/[Average melt viscosity from 40°C to 100°C (Pa s)]
　上記第１の熱プレス工程において、プレス圧力は例えば５ＭＰａ以上３０ＭＰａ以下、好ましくは１５ＭＰａ以上２５ＭＰａ以下であり、プレス温度は例えば６０℃以上１３０℃以下、好ましくは７０℃以上１１０℃以下であり、プレス時間は例えば２０分以上１２０分以下、好ましくは３０分以上１００分以下とすればよい。 In the first hot press step, the press pressure is, for example, 5 MPa or more and 30 MPa or less, preferably 15 MPa or more and 25 MPa or less, and the press temperature is, for example, 60° C. or more and 130° C. or less, preferably 70° C. or more and 110° C. or less, and press The time may be, for example, 20 minutes or more and 120 minutes or less, preferably 30 minutes or more and 100 minutes or less.
　上記第２の熱プレス工程において、プレス圧力は例えば０．５ＭＰａ以上２０ＭＰａ以下、好ましくは１ＭＰａ以上１０ＭＰａ以下であり、プレス温度は例えば１２０℃以上２３０℃以下、好ましくは１４０℃以上２２０℃以下であり、プレス時間は例えば３０分以上１５０分以下、好ましくは５０分以上１２０分以下である。第２の熱プレス工程では、異なる温度で２回以上プレスすることが好ましく、例えば１２０℃以上１６０℃以下で熱プレスした後、１７０℃以上２３０℃以下で再度熱プレスを行うことが好ましい。 In the second hot press step, the press pressure is, for example, 0.5 MPa or more and 20 MPa or less, preferably 1 MPa or more and 10 MPa or less, and the press temperature is, for example, 120° C. or more and 230° C. or less, preferably 140° C. or more and 220° C. or less. , the pressing time is, for example, 30 minutes or more and 150 minutes or less, preferably 50 minutes or more and 120 minutes or less. In the second hot-pressing step, it is preferable to press at different temperatures twice or more. For example, after hot-pressing at 120°C or higher and 160°C or lower, it is preferable to perform hot-pressing again at 170°C or higher and 230°C or lower.
　以下、実施例及び比較例により本発明をより具体的に説明するが、本発明はこれらに限定されるものではない。 The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these.
　なお、各物性の測定方法及び評価方法は以下のとおりである。
［空隙率］
　各実施例及び比較例で作製した樹脂シートの断面を研磨紙にて表面平滑化し、クロスセクションポリッシャー（日本電子株式会社制「ＩＢ－１９５００ＣＰ」）にて観察面を作製した。その後、断面をＰｔイオンスパッター（Ｅ－１０４５、日立ハイテクノロジーズ製）にてスパッタして得られた観察面を、走査電子顕微鏡（ＳＥＭ）を用いてシート全体が入るように５００倍断面画像を得た。
　次いで、この画像に対して画像処理及び解析を行った。「ＩｍａｇｅＪ」（Ｗａｙｎｅ　Ｒａｓｂａｎｄ開発）により、Ｔｈｒｅｓｈｏｌｄ機能により断面画像を空隙とその他の領域とで２値化し、断面の面積に対する空隙の面積割合から空隙率を求めた。 In addition, the measuring method and evaluation method of each physical property are as follows.
[Porosity]
The cross section of the resin sheet produced in each example and comparative example was smoothed with abrasive paper, and an observation surface was produced with a cross section polisher (manufactured by JEOL Ltd., "IB-19500CP"). After that, the observation surface obtained by sputtering the cross section with a Pt ion sputter (E-1045, manufactured by Hitachi High-Technologies) was scanned with a scanning electron microscope (SEM) to obtain a 500-fold cross-sectional image so that the entire sheet could be included. rice field.
Image processing and analysis were then performed on this image. Using "ImageJ" (developed by Wayne Rasband), the cross-sectional image was binarized into voids and other regions by the Threshold function, and the porosity was obtained from the area ratio of voids to the cross-sectional area.
［溶融粘度比率]　
　各実施例及び比較例の樹脂シート（サンプルサイズ１．５ｃｍ×１．５ｃｍ）について、レオメーター測定装置（ＴＡ　ｉｎｓｔｒｕｍｅｎｔｓ社製、「ＡＲＥＳ」）を用いて、角速度４０ｒａｄ／ｓｅｃ、測定温度４０～１９５℃、８℃/分の昇温速度の条件で各温度の溶融粘度を測定し、下記式に基づいて溶融粘度比率を求めた。
溶融粘度比率＝［４０℃から１９５℃における最大溶融粘度（Ｐａ・ｓ）］／［４０℃から１００℃における平均溶融粘度（Ｐａ・ｓ）］ [Melt viscosity ratio]
The resin sheet (sample size 1.5 cm × 1.5 cm) of each example and comparative example was measured using a rheometer measuring device (manufactured by TA instruments, "ARES") at an angular velocity of 40 rad/sec and a measurement temperature of 40 to 195. The melt viscosity at each temperature was measured under the conditions of °C and a heating rate of 8 °C/min, and the melt viscosity ratio was obtained based on the following formula.
Melt viscosity ratio = [Maximum melt viscosity from 40°C to 195°C (Pa s)]/[Average melt viscosity from 40°C to 100°C (Pa s)]
［熱伝導率］
　実施例、比較例で得られた積層体を１ｃｍ角にカットした後、両面にカーボンブラックをスプレーした測定サンプルに対して、測定装置「ナノフラッシュ」（ＮＥＴＺＳＣＨ社、型番：ＬＦＡ４４７）を用いて、レーザーフラッシュ法により熱伝導率の測定を行い、以下の基準で評価した。
（評価基準）
　ＡＡ：１０Ｗ／ｍ・Ｋ以上
　Ａ：５Ｗ／ｍ・Ｋ以上１０Ｗ／ｍ・Ｋ未満
　Ｂ：５Ｗ／ｍ・Ｋ未満 [Thermal conductivity]
After cutting the laminates obtained in Examples and Comparative Examples into 1 cm squares, carbon black was sprayed on both sides of the measurement samples. Thermal conductivity was measured by a laser flash method and evaluated according to the following criteria.
(Evaluation criteria)
AA: 10 W/m·K or more A: 5 W/m·K or more and less than 10 W/m·K B: Less than 5 W/m·K
［絶縁破壊電圧］
　実施例・比較例で作製した各積層体（６ｃｍ×６ｃｍ）にφ２の円電極を作成し、電極に対して２０ｋＶ／ｍｉｎの速度で電圧を印可した。測定試料が絶縁破壊を起こした電圧を絶縁破壊電圧とし、以下の評価基準に基づいて評価した。
（評価基準）
　Ａ：２ｋＶ以上
　Ｂ：２ｋＶ未満 [Insulation breakdown voltage]
A φ2 circular electrode was formed on each laminate (6 cm×6 cm) produced in Examples and Comparative Examples, and a voltage was applied to the electrode at a rate of 20 kV/min. The voltage at which dielectric breakdown occurred in the measurement sample was defined as the dielectric breakdown voltage, and evaluation was made based on the following evaluation criteria.
(Evaluation criteria)
A: 2 kV or more B: less than 2 kV
［引張りせん断測定］
　引張りせん断測定は、ＪＩＳ　Ｋ６８５０に準拠して、以下のように引張りせん断測定用の試料を作製して行った。
　図３に示すとおり、各実施例及び比較例において作製した樹脂シート３１（厚さが０．１２ｍｍ、長さＬが１２．５ｍｍ、幅２５ｍｍ）の両面に銅板３２及び銅板３３を積層した試料を作製した。それぞれの銅板は、長さ１００ｍｍ、幅２５ｍｍ、厚さ０．５ｍｍである。この際、図３のように樹脂シート３１の両面に、銅板３２の一端側３２ａ及び銅板３３の一端側３３ａが配置され、かつそれぞれの銅板の他端側３２ｂ及び３３ｂが互いに離れるように積層した。このように作製した試料を、５ＭＰａの圧力で１４５℃で３０分間プレスした後、１９５℃で５５分間プレスして、試料の樹脂シート３１を硬化させて、引張りせん断測定用の試料を作製した。該引張りせん断測定用の試料を引張り試験機によりせん断方向に引張り、その際の最大強度を引張りせん断力（ＭＰａ）とし、以下の基準で評価した。引張り試験機としては、Ａ＆Ｄ社製「テンシロンＲＴＣ－１３１０」を使用し、引張り速度１０ｍｍ／ｍｉｎとし、ロードセルは１０ｋＮを使用した。
（評価基準）
　ＡＡ：５ＭＰａ以上
　Ａ：３ＭＰａ以上５ＭＰａ未満
　Ｂ：３ＭＰａ未満 [Tensile shear measurement]
The tensile shear measurement was performed by preparing a sample for tensile shear measurement as follows, in accordance with JIS K6850.
As shown in FIG. 3, samples were prepared by laminating a copper plate 32 and a copper plate 33 on both sides of a resin sheet 31 (thickness: 0.12 mm, length L: 12.5 mm, width: 25 mm) prepared in each example and comparative example. made. Each copper plate is 100 mm long, 25 mm wide and 0.5 mm thick. At this time, as shown in FIG. 3, one end side 32a of the copper plate 32 and one end side 33a of the copper plate 33 are arranged on both sides of the resin sheet 31, and the other end sides 32b and 33b of the respective copper plates are laminated so that they are separated from each other. . The sample prepared in this manner was pressed at 145° C. for 30 minutes under a pressure of 5 MPa, and then pressed at 195° C. for 55 minutes to cure the resin sheet 31 of the sample, thereby preparing a sample for tensile shear measurement. The sample for tensile shear measurement was pulled in the shear direction by a tensile tester, and the maximum strength at that time was taken as the tensile shear force (MPa) and evaluated according to the following criteria. As the tensile tester, "Tensilon RTC-1310" manufactured by A&D was used, the tensile speed was 10 mm/min, and the load cell was 10 kN.
(Evaluation criteria)
AA: 5 MPa or more A: 3 MPa or more and less than 5 MPa B: less than 3 MPa
　実施例及び比較例で使用した各成分は以下の通りである。
（バインダー樹脂）
エポキシ樹脂：「ｊＥＲ－８２８」、ジャパンエポキシレジン社製
フェノキシ樹脂：「ｊＥＲ－１２５６」、ジャパンエポキシレジン社製
※各実施例、比較例において、熱硬化性成分は、エポキシ樹脂とフェノキシ樹脂とをそれぞれ７．４：２．６の体積比率で使用した。
（硬化剤）
「ＨＮ２２００」、昭和電工マテリアル社製
「１Ｂ２ＭＺ」、四国化成社製
※各実施例、比較例において、硬化剤は、「ＨＮ２２００」と「１Ｂ２ＭＺ」とをそれぞれ８．９．：１．１の体積比率で使用した。
（窒化ホウ素凝集粒子）
・水島合金鉄株式会社製「ＨＰ－４０」、凝集粒子の平均粒子径４０μｍ
・昭和電工株式会社製「ＵＨＰ－Ｇ１Ｈ」、凝集粒子の平均粒子径３３μｍ
（アルミナ）
・昭和電工株式会社製「ＣＢ－Ｐ１０」、平均粒子径８μｍ
（窒化アルミニウム）
・株式会社トクヤマ社製「ＴＦＺ－Ａ１０Ｐ」、平均粒子径９μｍ Components used in Examples and Comparative Examples are as follows.
(binder resin)
Epoxy resin: “jER-828”, phenoxy resin manufactured by Japan Epoxy Resin: “jER-1256” manufactured by Japan Epoxy Resin * In each example and comparative example, the thermosetting component is an epoxy resin and a phenoxy resin. They were used at a volume ratio of 7.4:2.6, respectively.
(curing agent)
"HN2200", "1B2MZ" manufactured by Showa Denko Materials Co., Ltd., and "1B2MZ" manufactured by Shikoku Kasei Co., Ltd. : used at a volume ratio of 1.1.
(boron nitride aggregate particles)
・ “HP-40” manufactured by Mizushima Ferroalloy Co., Ltd., average particle size of aggregated particles 40 μm
・ “UHP-G1H” manufactured by Showa Denko Co., Ltd., average particle size of aggregated particles 33 μm
(alumina)
・ “CB-P10” manufactured by Showa Denko Co., Ltd., average particle size 8 μm
(aluminum nitride)
・ “TFZ-A10P” manufactured by Tokuyama Co., Ltd., average particle size 9 μm
［実施例１］
　表１に記載のバインダー樹脂、無機フィラー、及び硬化剤を表１に記載の量となるように混合し、硬化性樹脂組成物を得た。該硬化性樹脂組成物を離型ＰＥＴシート（厚み４０μｍ）上に塗工し、５０℃のオーブン内で１０分間乾燥して、離型ＰＥＴシート上に硬化性樹脂組成物からなる塗膜を形成させた試料を２つ作製した。このように作製した２つの試料を塗膜が接触するように積層して積層物を作製し、該積層物を２枚の金属板に挟んだ後、プレス圧力１８ＭＰａ、プレス温度１００℃、プレス時間４５分のプレス溶融条件で熱プレスした。このようにして、離型ＰＥＴシートに挟まれた樹脂シートを得た。該樹脂シートを用いて、各種測定を行った。
　別途、離型ＰＥＴシートを剥がして、樹脂シートの両面を、第１の金属層（銅板、厚さ５００μｍ）と第２の金属層（アルミニウム板、厚さ１．０ｍｍ）とで挟み、５ＭＰａの圧力で、１４５℃で３０分間プレスした後、１９５℃で５５分間プレスし、第１の金属層、樹脂シートの硬化物、第２の金属層がこの順に積層された積層体を作製した。該積層体を用いて、各種測定を行った。 [Example 1]
The binder resin, inorganic filler, and curing agent shown in Table 1 were mixed in the amounts shown in Table 1 to obtain a curable resin composition. The curable resin composition is applied onto a release PET sheet (40 μm thick) and dried in an oven at 50° C. for 10 minutes to form a coating film of the curable resin composition on the release PET sheet. Two samples were prepared. The two samples thus prepared are laminated so that the coating films are in contact with each other to prepare a laminate, and after sandwiching the laminate between two metal plates, press pressure 18 MPa, press temperature 100 ° C., press time It was hot pressed under press melting conditions for 45 minutes. Thus, a resin sheet sandwiched between release PET sheets was obtained. Various measurements were performed using the resin sheet.
Separately, the release PET sheet was peeled off, and both sides of the resin sheet were sandwiched between a first metal layer (copper plate, thickness 500 μm) and a second metal layer (aluminum plate, thickness 1.0 mm), and subjected to a pressure of 5 MPa. After pressing for 30 minutes at 145° C., pressing was performed at 195° C. for 55 minutes to produce a laminate in which the first metal layer, the cured resin sheet, and the second metal layer were laminated in this order. Various measurements were performed using the laminate.
［実施例２～１２、比較例１～６］
　硬化性樹脂組成物に含まれる各成分の種類及び量、並びにプレス溶融条件を表１及び２のとおり変更した以外は、実施例１と同様にして、樹脂シート及び積層体を作製し、各種評価を行った。 [Examples 2 to 12, Comparative Examples 1 to 6]
A resin sheet and a laminate were prepared in the same manner as in Example 1, except that the type and amount of each component contained in the curable resin composition and the press melting conditions were changed as shown in Tables 1 and 2, and various evaluations were performed. did
　［比較例７］
　硬化性樹脂組成物に含まれる窒化ホウ素凝集粒子（ＢＮ）の含有量を８５体積％に変更した以外は、実施例１と同様にして、樹脂シート及び積層体を作製しようとしたところ、バインダー樹脂の量が少ないため硬化性樹脂組成物が十分に硬化せずに樹脂シート及び積層体を得られなかった。 [Comparative Example 7]
An attempt was made to produce a resin sheet and a laminate in the same manner as in Example 1, except that the content of the boron nitride aggregated particles (BN) contained in the curable resin composition was changed to 85% by volume. Because the amount of was small, the curable resin composition was not sufficiently cured, and the resin sheet and laminate could not be obtained.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　各実施例の結果より、本発明の各要件を満足する樹脂シートの硬化物は、熱伝導性及び絶縁性が高く、さらに引張せん断力が高いことより、金属板に対する密着性にも優れることが分かった。
　これに対して、窒化ホウ素の含有量が少ない比較例１、６は熱伝導性が低くなり、ボイド率が所定の範囲外である比較例２，３，６は絶縁性が低くなることが分かった。さらに、溶融粘度比率が小さい比較例４、５については、引張せん断力が低いことより、金属板に対する密着性に劣ることが分かった。 From the results of each example, it was found that the cured product of the resin sheet satisfying each requirement of the present invention has high thermal conductivity and insulating properties, and also has high tensile shearing force, so that it has excellent adhesion to the metal plate. Do you get it.
On the other hand, Comparative Examples 1 and 6, in which the content of boron nitride is small, have low thermal conductivity, and Comparative Examples 2, 3, and 6, in which the void fraction is outside the predetermined range, have low insulating properties. rice field. Furthermore, it was found that Comparative Examples 4 and 5, in which the melt viscosity ratio was small, had poor adhesion to the metal plate due to the low tensile shear force.
１０　樹脂シートの硬化物
１１　金属ベース板
１２　金属板
１３　積層体
１４　半導体素子
１５　半導体装置
１６　接続導電部
１７　ワイヤ
１９　封止樹脂
２０　リード
３１　樹脂シート
３２，３３　銅板 10 Cured product of resin sheet 11 Metal base plate 12 Metal plate 13 Laminate 14 Semiconductor element 15 Semiconductor device 16 Connection conductive part 17 Wire 19 Sealing resin 20 Lead 31 Resin sheets 32, 33 Copper plate

Claims (14)

  1. 　バインダー樹脂及び窒化ホウ素粒子を含有する樹脂シートであって、
    　窒化ホウ素粒子の含有量が３０体積％以上８０体積％以下であり、
    　樹脂シートの断面における空隙率が０．０１％以上２．０％以下であり、
    　４０℃から１９５℃まで８℃／分の昇温速度で測定する溶融粘度測定において、下記式で求められる溶融粘度比率が２以上である、樹脂シート。
    溶融粘度比率＝［４０℃から１９５℃における最大溶融粘度（Ｐａ・ｓ）］／［４０℃から１００℃における平均溶融粘度（Ｐａ・ｓ）］     A resin sheet containing a binder resin and boron nitride particles,
    The content of boron nitride particles is 30% by volume or more and 80% by volume or less,
    The porosity in the cross section of the resin sheet is 0.01% or more and 2.0% or less,
    A resin sheet having a melt viscosity ratio of 2 or more, as determined by the following formula, in melt viscosity measurement from 40°C to 195°C at a heating rate of 8°C/min.
    Melt viscosity ratio = [Maximum melt viscosity from 40°C to 195°C (Pa s)]/[Average melt viscosity from 40°C to 100°C (Pa s)]
  2. 　前記窒化ホウ素粒子以外の無機フィラーを含有する、請求項１に記載の樹脂シート。 The resin sheet according to claim 1, containing an inorganic filler other than the boron nitride particles.
  3. 　前記窒化ホウ素粒子以外の無機フィラーが、アルミナ、窒化アルミニウム、酸化マグネシウム、ダイヤモンド、及び炭化ケイ素からなる群から選択される少なくとも１種である、請求項２に記載の樹脂シート。 The resin sheet according to claim 2, wherein the inorganic filler other than the boron nitride particles is at least one selected from the group consisting of alumina, aluminum nitride, magnesium oxide, diamond, and silicon carbide.
  4. 　前記窒化ホウ素粒子以外の無機フィラーの含有量が、２体積％以上５５体積％以下である、請求項２又は３に記載の樹脂シート。 The resin sheet according to claim 2 or 3, wherein the content of the inorganic filler other than the boron nitride particles is 2% by volume or more and 55% by volume or less.
  5. 　前記窒化ホウ素粒子と前記窒化ホウ素粒子以外の無機フィラーとの合計の含有量が、６５体積％以上８０体積％以下である、請求項２～４のいずれか１項に記載の樹脂シート。 The resin sheet according to any one of claims 2 to 4, wherein the total content of the boron nitride particles and the inorganic filler other than the boron nitride particles is 65% by volume or more and 80% by volume or less.
  6. 　前記窒化ホウ素粒子が、窒化ホウ素凝集粒子を含む請求項１～５のいずれか１項に記載の樹脂シート。 The resin sheet according to any one of claims 1 to 5, wherein the boron nitride particles contain aggregated boron nitride particles.
  7. 　請求項１～６のいずれか１項に記載の樹脂シートの硬化物。 A cured product of the resin sheet according to any one of claims 1 to 6.
  8. 　熱伝導率が、１０Ｗ／(ｍ・Ｋ）以上である請求項７に記載の樹脂シートの硬化物。 The cured resin sheet according to claim 7, which has a thermal conductivity of 10 W/(m·K) or more.
  9. 　請求項７又は８に記載の樹脂シートの硬化物と、金属ベース板と、金属板とを備え、前記金属ベース板上に、前記樹脂シートの硬化物と前記金属板をこの順に備える積層体。 A laminate comprising a cured product of the resin sheet according to claim 7 or 8, a metal base plate, and a metal plate, wherein the cured product of the resin sheet and the metal plate are provided in this order on the metal base plate.
  10. 　前記積層体が、回路基板である請求項９に記載の積層体。 The laminate according to claim 9, wherein the laminate is a circuit board.
  11. 　前記金属板が、回路パターンを有する請求項９又は１０に記載の積層体。 The laminate according to claim 9 or 10, wherein the metal plate has a circuit pattern.
  12. 　請求項９～１１のいずれか１項に記載の積層体と、前記金属板の上に設けられる半導体素子とを備える半導体装置。 A semiconductor device comprising the laminate according to any one of claims 9 to 11 and a semiconductor element provided on the metal plate.
  13. 　樹脂シートの硬化物と、金属ベース板と、金属板とを備え、前記金属ベース板上に、前記樹脂シートの硬化物と前記金属板をこの順に備える積層体の製造方法であって、
    　バインダー樹脂及び窒化ホウ素粒子を含有する硬化性樹脂組成物を加熱及び加圧することにより半硬化状態の樹脂シートを作製する第１の熱プレス工程と、
    　前記半硬化状態の樹脂シートを、前記金属ベース板と前記金属板の間に配置する積層工程と、
    　前記積層工程で積層された半硬化状態の樹脂シートを加熱及び加圧することにより本硬化させ積層体を得る第２の熱プレス工程と、を有し、
    　前記半硬化状態の樹脂シートの断面における空隙率が０．０１％以上２．０％以下であり、
    　４０℃から１９５℃まで８℃／分の昇温速度で測定する溶融粘度測定において、下記式で求められる前記半硬化状態の樹脂シートの溶融粘度比率が２以上である、積層体の製造方法。
    溶融粘度比率＝［４０℃から１９５℃における最大溶融粘度（Ｐａ・ｓ）］／［４０℃から１００℃における平均溶融粘度（Ｐａ・ｓ）］     A method for manufacturing a laminate comprising a cured resin sheet, a metal base plate, and a metal plate, wherein the cured resin sheet and the metal plate are provided in this order on the metal base plate,
    A first hot press step of producing a semi-cured resin sheet by heating and pressing a curable resin composition containing a binder resin and boron nitride particles;
    a laminating step of disposing the semi-cured resin sheet between the metal base plate and the metal plate;
    a second hot press step for obtaining a laminate by heating and pressing the semi-cured resin sheets laminated in the lamination step to obtain a laminate,
    The semi-cured resin sheet has a cross-sectional porosity of 0.01% or more and 2.0% or less,
    A method for producing a laminate, wherein the melt viscosity ratio of the semi-cured resin sheet obtained by the following formula is 2 or more in a melt viscosity measurement in which the temperature is increased from 40° C. to 195° C. at a rate of 8° C./min.
    Melt viscosity ratio = [Maximum melt viscosity from 40°C to 195°C (Pa s)]/[Average melt viscosity from 40°C to 100°C (Pa s)]
  14. 　前記第１の熱プレス工程のプレス温度が６０℃以上１３０℃以下であり、プレス圧力が５ＭＰａ以上３０ＭＰａ以下である、請求項１３に記載の積層体の製造方法。 The method for manufacturing a laminate according to claim 13, wherein the pressing temperature in the first hot pressing step is 60°C or higher and 130°C or lower, and the pressing pressure is 5 MPa or higher and 30 MPa or lower.
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JP2013227451A (en) * 2012-04-26 2013-11-07 Hitachi Chemical Co Ltd Epoxy resin composition, semi-cured epoxy resin composition, cured epoxy resin composition, resin sheet, prepreg, laminate, metal substrate, and printed wiring board
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