Laminate and semiconductor package

Abstract

To provide a laminate that enables coexistence of high thermal conductivity and resistance to reflow.SOLUTION: A laminate comprises, in this order: a metal-particle-containing layer containing first metal particles and a first resin; a metal layer having a plurality of openings; and a low-melting-point-metal-particle-containing layer containing low-melting-point metal particles, second metal particles, and a second resin, wherein the first metal particles and the second metal particles contain one or more metals selected from the group consisting of copper, silver, gold, aluminum, zinc, platinum, and nickel.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laminate and a semiconductor package.

Background Art

[0002] Conventionally, in order to dissipate heat generated during driving of an integrated circuit (IC) chip or the like to a heat sink via a heat spreader, the space between the IC chip and the heat spreader and the space between the heat spreader and the heat sink are filled with a heat conductive member, and the importance of heat dissipation for efficiently dissipating heat generated from the IC to the heat sink side has been increasing.

[0003] So far, a heat dissipating film formed by laminating a graphite-containing resin layer and a metal foil, a metal plate, a metal mesh, or sheet-like graphite has been reported, in which the thickness X of the graphite-containing resin layer satisfies the relationship of 0.5Y < X < 1.5Y with respect to the average particle diameter Y of the graphite particles (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the laminate described in the conventional Patent Document 1, the heat conduction between the graphite contained in the graphite-containing resin layer and the metal foil depends on contact, and the contact thermal resistance of that portion cannot be ignored, resulting in a problem of insufficient thermal conductivity.

[0006] An object of the present invention is to solve the above-described conventional problems and achieve the following object. That is, an object of the present invention is to provide a laminate capable of achieving both high thermal conductivity and reflow resistance.

Means for Solving the Problems

[0007] The means for solving the above problems are as follows: <1> a metal particle-containing layer containing first metal particles and a first resin; a metal layer having a plurality of openings; a low-melting-point metal particle-containing layer containing low-melting-point metal particles, second metal particles, and a second resin, in this order; The laminate is characterized in that the first metal particles and the second metal particles contain one or more metals selected from the group consisting of copper, silver, gold, aluminum, zinc, platinum, and nickel. <2> The metal layer contains one or more metals selected from the group consisting of copper, nickel, and aluminum. <1> 1. The laminate according to claim 1. <3> The metal layer is surface-treated with one or more metals selected from the group consisting of copper, silver, gold, tin, and nickel. <1> or <2> 1. The laminate according to claim 1. <4> The aperture ratio of the metal layer is 10% or more and 75% or less. <1> from <3> The laminate according to any one of the above items. <5> The first resin contains a thermosetting resin. <1> from <4> The laminate according to any one of the above items. <6> The second resin contains a thermosetting resin. <1> from <5> The laminate according to any one of the above items. <7> an integrated circuit member; A heat dissipation member; Between the integrated circuit member and the heat dissipation member, <1> from <6> and a laminate according to any one of the above items. [Effects of the Invention]

[0008] According to the present invention, it is possible to solve the above-mentioned problems in the prior art, achieve the above-mentioned object, and provide a laminate that can achieve both high thermal conductivity and reflow resistance. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of the laminate of the present embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA' of the laminate of FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view showing another example of the laminate of the present embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view showing another example of the laminate of the present embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view showing another example of the laminate of the present embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view showing another example of the laminate of the present embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view showing an example of the semiconductor package of this embodiment. [Figure 8] FIG. 8 is a top view showing a metal layer in the laminate of Example 1. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Laminate) The laminate of the present invention is a laminate having, in this order, a metal particle-containing layer containing first metal particles and a first resin, a metal layer having a plurality of openings, and a low-melting point metal particle-containing layer containing low-melting point metal particles, second metal particles, and a second resin. The first metal particles and the second metal particles contain one or more metals selected from the group consisting of copper, silver, gold, aluminum, zinc, platinum, and nickel.

[0011] In the laminate of this embodiment, the metal particle-containing layer and the low-melting-point metal particle-containing layer are in contact with the metal layer, and are in contact with each other through the openings in the metal layer. This ensures adhesion of the laminate, adhesion to the substrate, and thermal conductivity in the thickness direction of the laminate, and also provides excellent reflow resistance. Furthermore, by having a metal layer with multiple openings and communicating in the planar direction, the laminate has thermal conductivity not only in the thickness direction but also in the planar direction, resulting in excellent thermal conductivity. Therefore, by providing the laminate between the heating element and the heat dissipation member, heat from the heating element can be efficiently dissipated through the laminate, providing a laminate that combines high thermal conductivity and reflow resistance.

[0012] 1 and 2 are a schematic cross-sectional view showing an example of a laminate according to the present embodiment, and a schematic cross-sectional view taken along the line AA' of the laminate, where Fig. 1 is a schematic cross-sectional view taken along the line BB' of Fig. 2. The laminate 10 shown in FIGS. 1 and 2 has, in this order, a metal particle-containing layer 11, a metal layer 12, and a low-melting-point metal particle-containing layer 13, and the metal layer 12 has a plurality of openings 12a. From the viewpoint of thermal conductivity, it is preferable that the metal particle-containing layer 11 and the low-melting-point metal particle-containing layer 13 contact each other at each of the plurality of openings 12a.

[0013] <Metal layer> The metal layer has a plurality of openings, which are through holes or openings that penetrate from one surface of the metal layer to the other surface. The material of the metal layer preferably contains a metal with high thermal conductivity, and more preferably consists of the metal. As the metal, aluminum, nickel, iron, gold, silver, copper, zinc, and tin are preferred from the viewpoints of thermal conductivity and safety, and copper, nickel, and aluminum are more preferred. These may be used alone or in combination of two or more. Among these, copper foil, nickel foil, and aluminum foil are preferred because they are all available at low cost and through holes can be easily formed in them.

[0014] The metal layer is preferably surface-treated with one or more metals selected from the group consisting of copper, silver, gold, tin, and nickel, which improves the wettability of the metal layer surface when the low-melting-point metal particles melt, and alloys the low-melting-point metal particles to improve the thermal conductivity of the laminate.

[0015] [Aperture ratio of metal layer] The aperture ratio of the metal layer is from 10% to 75%, preferably from 30% to 70%, more preferably from 30% to 60%, and even more preferably from 30% to 55%, in order to achieve excellent adhesion to substrates such as integrated circuit components and heat dissipation components and excellent reflow resistance. When the opening ratio of the metal layer is 10% or more and 75% or less, the thermal conductivity of the laminate can be ensured and the durability can be improved. Here, the aperture ratio of the metal layer is the total area (%) of multiple openings per area of ​​the metal layer when the metal layer is viewed in plan, and can be measured using, for example, image analysis software.

[0016] [Shape Pattern] The shape pattern of the metal layer is not particularly limited as long as it has a plurality of openings and can be appropriately selected depending on the purpose, and examples thereof include a pattern in which a plurality of figures are arranged. Among these, a pattern in which a plurality of shapes are regularly arranged is preferred from the viewpoint of uniformity of thermal conductivity. Examples of the shapes include squares, circles, hexagons, triangles, rectangles, and ellipses. 1, the openings 12a may be square, and a plurality of openings may be arranged in parallel (at 90° angles) (referred to as "parallel squares") In other words, the metal layer 12 may have a lattice-like mesh pattern.

[0017] Alternatively, the patterns may be arranged in a regular pattern as shown in FIGS. Here, as described above, FIG. 1 is a schematic cross-sectional view showing an example of the laminate of this embodiment, and FIGS. 3 to 6 are schematic cross-sectional views showing other examples of the laminate of this embodiment. The shape pattern shown in FIG. 3 is a pattern in which the openings 12a are circular and a plurality of openings are arranged at 60° angles to each other (a so-called 60° staggered pattern, referred to as "60° staggered"). The shape pattern shown in FIG. 4 is a pattern in which the openings 12a are regular hexagons, and a plurality of openings are arranged at 60° angles to each other (referred to as "regular hexagon 60° staggered"). The shape pattern shown in FIG. 5 is a pattern in which openings 12a are equilateral triangles, and a plurality of openings are arranged at 60° angles to each other (referred to as an "equal triangle arrangement"). The shape pattern shown in FIG. 6 is a pattern in which the openings 12a are rectangular and multiple openings are arranged alternately, i.e., arranged with a shift of 1 / 2 the length of the long side in the direction of the long side of the rectangle (referred to as "alternate rectangles").

[0018] The aperture ratio of the metal layer can be adjusted by, for example, the opening area (or the length of the long side) of the openings and the pitch of the openings (that is, the distance between the centers of adjacent openings). The length of the long side of the opening is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm or more and 1,000 μm or less, and more preferably 50 μm or more and 500 μm or less.

[0019] The thermal conductivity of the metal layer is not particularly limited and can be selected appropriately depending on the purpose. From the viewpoint of thermal conductivity, however, it is preferably 20 W / (m·K) or more, and more preferably 25 W / (m·K) or more. The thermal conductivity of the metal is not particularly limited and can be selected appropriately depending on the purpose. From the viewpoint of thermal conductivity, however, it is preferably 50 W / (m·K) or more, more preferably 100 W / (m·K) or more, and even more preferably 200 W / (m·K) or more.

[0020] The average thickness of the metal layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm to 150 μm, more preferably 15 μm to 100 μm, which allows the laminate to have both high thermal conductivity and high durability.

[0021] <Metal particle containing layer> The metal particle-containing layer contains first metal particles and a first resin, and may further contain other components as needed.

[0022] <<First Resin>> The first resin is not particularly limited and can be appropriately selected depending on the purpose, and both thermosetting resins and thermoplastic resins can be suitably used. These may be used alone or in combination of two or more. The laminate of this embodiment exerts its effects by, for example, inserting it between an IC chip and a heat spreader, and then heating it while applying pressure as needed to bond the IC chip and the heat spreader. To further exert the effects, the first resin is preferably a thermosetting resin, and more preferably contains a thermoplastic resin and a thermosetting resin. The first resin and the second resin may be collectively referred to as "resin."

[0023] -Thermosetting resin- As the thermosetting resin, it is preferable to use at least one of an oxirane ring compound and an oxetane compound.

[0024] --Oxirane ring compounds-- The oxirane ring compound is a compound having an oxirane ring, and examples thereof include epoxy resins. The epoxy resin is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include glycidyl ether type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A type epoxy resins, trisphenol type epoxy resins, tetraphenol type epoxy resins, phenol-xylylene type epoxy resins, naphthol-xylylene type epoxy resins, phenol-naphthol type epoxy resins, phenol-dicyclopentadiene type epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins. These may be used alone or in combination of two or more.

[0025] --Oxetane compounds-- The oxetane compound is a compound having an oxetanyl group, and may be an aliphatic compound, an alicyclic compound, or an aromatic compound. The oxetane compound may be a monofunctional oxetane compound having only one oxetanyl group, or may be a polyfunctional oxetane compound having two or more oxetanyl groups.

[0026] The oxetane compound is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include 3,7-bis(3-oxetanyl)-5-oxa-nonane, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 1,2-bis[(3-ethyl-3-oxetanylmethoxy)methyl]ethane, 1,3-bis[(3-ethyl-3-oxetanylmethoxy)methyl]propane, ethylene glycol bis(3-ethyl-3-oxetanylmethyl)ether, triethylene glycol bis(3-ethyl-3-oxetanylmethyl)ether, tetraethylene glycol bis(3-ethyl-3-oxetanylmethyl)ether, and 1,4-bis(3-ethyl-3-oxetanylmethoxy)butane. oxetane, 1,6-bis(3-ethyl-3-oxetanylmethoxy)hexane, 3-ethyl-3-(phenoxy)methyloxetane, 3-ethyl-3-(cyclohexyloxymethyl)oxetane, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3-(chloromethyl)oxetane, 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane, xylylene bisoxetane (OXT-121), 4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl (OXBP), isophthalic acid bis[(3-ethyl-3-oxetanyl)methyl]ester (OXIPA), and the like. These may be used alone or in combination of two or more.

[0027] As the oxetane compound, commercially available products can be used, and examples of the commercially available products include the "Aron Oxetane (registered trademark)" series sold by Toagosei Co., Ltd. and the "ETERNACOLL (registered trademark)" series sold by Ube Industries, Ltd.

[0028] Among the oxirane ring compounds and oxetane compounds, glycidyl ether type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, phenol-dicyclopentadiene type epoxy resins, bisphenol A type epoxy resins, aliphatic epoxy resins, xylylene bisoxetane (OXT-121), 4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl (OXBP), and isophthalic acid bis[(3-ethyl-3-oxetanyl)methyl]ester (OXIPA) are preferred.

[0029] The content of the thermosetting resin is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.5% by volume or more and 60% by volume or less relative to the total amount of the metal particle-containing layer.

[0030] --Hardening agent-- The metal particle-containing layer or the composition for forming the metal particle-containing layer preferably contains a curing agent together with the thermosetting resin, and the metal particle-containing layer preferably contains a cured product obtained by curing the thermosetting resin and the curing agent. The curing agent is a curing agent that corresponds to the thermosetting resin (curing component), and examples thereof include polyaddition type curing agents such as polyfunctional carboxylic acids, acid anhydride type curing agents, aliphatic amine type curing agents, aromatic amine type curing agents (for example, imidazole type curing agents), phenol type curing agents, and mercaptan type curing agents, and catalyst type curing agents such as imidazole. These may be used alone or in combination of two or more. Among these, aromatic amine-based curing agents are preferred, and imidazole-based curing agents are more preferred.

[0031] Commercially available imidazole curing agents can be used, and examples of the commercially available imidazole curing agents include 2P4MZ, 2PZ, and 2E4MZ-A from the "Curezol" series sold by Shikoku Chemical Industry Co., Ltd.; and HX-3941HP, HXA3922HP, HXA3792, HXA3932HP, HXA3042HP, HXA9322HP, HXA9382HP, HXA5052HP, and HXA3542HP from the "Novacure (registered trademark)" series sold by Asahi Chemical Industry Co., Ltd.

[0032] Examples of the acid anhydride curing agent include cyclohexane-1,2-dicarboxylic acid anhydride and mono-acid anhydrides of tricarboxylic acids. Examples of the mono-acid anhydrides of tricarboxylic acids include cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride.

[0033] -Thermoplastic resin- The thermoplastic resin is not particularly limited and can be appropriately selected depending on the purpose. Examples of the thermoplastic resin include polyolefin resins such as polyethylene resin, polypropylene resin, and polybutylene resin; methacrylic resins such as polymethyl methacrylate resin; polystyrene resin, ABS resin, and AS resin; polyester resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polytrimethylene terephthalate resin, polyethylene naphthalate (PEN) resin, and poly 1,4-cyclohexyldimethylene terephthalate (PCT) resin; polyamide (PA) resins such as 6-nylon resin and 6,6-nylon resin; polyvinyl chloride resin, polyoxymethylene (POM) resin, polycarbonate (PC) resin, and polyphenylene sulfide resin. Examples of suitable resins include polyphenylene ether (PPS) resin, modified polyphenylene ether (PPE) resin, polyetherimide (PEI) resin, polyamide-imide resin, polysulfone (PSF) resin, polyethersulfone (PES) resin, polyketone resin, polyarylate (PAR) resin, polyethernitrile (PEN) resin, polyetherketone (PEK) resin, polyetheretherketone (PEEK) resin, polyetherketoneketone (PEKK) resin, polyimide (PI) resin, polyamide-imide (PAI) resin, phenoxy resin, and fluorine (F) resin; liquid crystal polymer resins such as liquid crystal polyester resin; and thermoplastic elastomers such as polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, polyisoprene, and fluorine-based resins.

[0034] The content of the thermoplastic resin is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 1% by volume or more and 50% by volume or less, and more preferably 1% by volume or more and 30% by volume or less, relative to the total amount of the metal particle-containing layer.

[0035] <<First metal particles>> The first metal particles contain one or more metals selected from the group consisting of copper, silver, gold, aluminum, zinc, platinum, and nickel. The first metal particles and the second metal particles may be collectively referred to as "metal particles." The metal particles may have a metal layer applied to their surface by plating, vapor deposition, or the like, and examples thereof include silver-coated metal particles such as silver-coated copper particles, silver-coated aluminum particles, and silver-coated nickel particles; copper-coated metal particles such as copper-coated aluminum particles and copper-coated nickel particles; and gold-coated metal particles such as gold-coated copper particles, gold-coated aluminum particles, and gold-coated nickel particles. The shape of the first metal particles is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include spherical, flat, granular, and needle-like shapes.

[0036] The first metal particles preferably contain one or more metals selected from the group consisting of copper, silver, and gold. In this case, the first metal particles are more preferably sinterable metal particles that can be sintered by a sintering process.

[0037] The sinterable metal particles are particles in which at least a portion of the surface layer of each particle is formed of metal and which adhere to each other when heated at a temperature below the melting point of the metal. Because the metal particles are sinterable metal particles, at least a portion of the sinterable metal particles can be sintered by subjecting the laminate of this embodiment to a thermal curing treatment. This makes it easier to form heat transfer paths within the laminate of this embodiment, leading to improved thermal conductivity. In particular, sinterable metal particles that have excellent thermal conductivity in the thickness direction of the laminate include, for example, particles whose surface layer is formed of at least one of gold, silver, and copper.

[0038] The volume average particle diameter (D 50 ) is preferably 0.1 μm or more and 50 μm or less, and more preferably 0.5 μm or more and 30 μm or less. The volume average particle diameter (D 50 ) can be measured, for example, by a laser diffraction / scattering particle size distribution measuring device (product name: Microtrac MT3300EXII). The lower limit of the volume filling rate of the metal particles is preferably 30% by volume or more, more preferably 50% by volume or more, and the upper limit of the volume filling rate of the metal particles is preferably 90% by volume or less, more preferably 85% by volume or less. When the volume filling rate of the metal particles is 30% by volume or more and 90% by volume or less, the thermally conductive composition can achieve high thermal conductivity and low thermal resistance.

[0039] The content of the first metal particles is not particularly limited and can be selected appropriately depending on the purpose. From the viewpoint of increasing the thermal conductivity without impairing the adhesiveness of the metal particle-containing layer, the content is preferably 10% by volume or more and 80% by volume or less, more preferably 20% by volume or more and 70% by volume or less, and even more preferably 30% by volume or more and 65% by volume or less, relative to the total amount of the metal particle-containing layer.

[0040] The volume average particle diameter (D 50 ) is preferably 0.3 μm or more and 30 μm or less, and more preferably 0.5 μm or more and 10 μm or less. The volume average particle diameter (D 50 ) can be measured, for example, by a laser diffraction / scattering particle size distribution measuring device (Microtrac MT3300EXII).

[0041] The average thickness of the metal particle-containing layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm to 200 μm, more preferably 15 μm to 100 μm. When the average thickness is 10 μm or more, the durability of the laminate is ensured, and when it is 200 μm or less, the thermal conductivity is good. When the metal particle-containing layer fills at least a portion of the openings of the adjacent metal layer and has protrusions within the openings, the thickness of the metal particle-containing layer in the region without the protrusions is measured without taking the protrusions into consideration. The average thickness can be calculated as the average value of the thicknesses at any three or more points.

[0042] <Layer containing low-melting-point metal particles> The low-melting-point metal particle-containing layer contains low-melting-point metal particles, second metal particles, and a second resin, and may further contain other components as required.

[0043] <<Second Resin>> The second resin is not particularly limited and can be appropriately selected depending on the purpose, and both a thermosetting resin and a thermoplastic resin can be suitably used. Among these, a thermosetting resin is preferred, and a mixture of a thermoplastic resin and a thermosetting resin is more preferred. The second resin can be selected appropriately from the items described for the first resin. The first resin and the second resin may be the same or different from each other.

[0044] The content of the thermosetting resin is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.5% by volume to 30% by volume based on the total amount of the low-melting-point metal particle-containing layer. The content of the thermoplastic resin is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 1% by volume or more and 50% by volume or less, and more preferably 1% by volume or more and 30% by volume or less, relative to the total amount of the low-melting-point metal particle-containing layer.

[0045] <<Second metal particles>> The second metal particles contain one or more metals selected from the group consisting of copper, silver, gold, aluminum, zinc, platinum, and nickel. The second metal particles can be selected from the items described for the first metal particles as appropriate. The first metal particles and the second metal particles may be the same or different from each other.

[0046] The content of the second metal particles is not particularly limited and can be selected appropriately depending on the purpose. From the viewpoint of increasing the thermal conductivity without impairing the adhesiveness of the low-melting-point metal particle-containing layer, the content is preferably 10% by volume or more and 80% by volume or less, more preferably 15% by volume or more and 70% by volume or less, and even more preferably 20% by volume or more and 60% by volume or less, relative to the total amount of the low-melting-point metal particle-containing layer.

[0047] The volume average particle diameter (D 50 ) is preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 70 μm or less, and even more preferably 5 μm or more and 50 μm or less. When the volume average particle size of the second thermally conductive particles is 1 μm or more and 100 μm or less, excellent thermal conductivity can be achieved. The volume average particle size of the second metal particles can be measured in the same manner as the volume average particle size of the first metal particles.

[0048] <<Low melting point metal particles>> As the low melting point metal particles, solder particles as specified in JIS Z3282-1999 are preferably used. The low-melting-point metal refers to the low-melting-point metal particles and the low-melting-point metal formed by melting and solidifying the low-melting-point metal particles.

[0049] Examples of the solder particles include Sn-Pb solder particles, Pb-Sn-Sb solder particles, Sn-Sb solder particles, Sn-Pb-Bi solder particles, Sn-Bi-Ag solder particles, Sn-Cu solder particles, Sn-Pb-Cu solder particles, Sn-In solder particles, Sn-Ag solder particles, Sn-Pb-Ag solder particles, Pb-Ag solder particles, Sn-Ag-Cu solder particles, etc. These may be used alone or in combination of two or more. Among these, solder particles containing Sn and at least one selected from Bi, Ag, Cu, and In are preferred, Sn-Bi based solder particles, Sn-Bi-Ag based solder particles, Sn-Ag-Cu based solder particles, and Sn-In based solder particles are more preferred, and Sn-Bi based solder particles containing Sn and Bi are even more preferred.

[0050] The shape of the low melting point metal particles is not particularly limited and can be appropriately selected depending on the purpose. Examples include spherical, flat, granular, and needle-like shapes. The melting point of the low-melting-point metal particles is preferably 100°C or higher and 250°C or lower, and more preferably 120°C or higher and 200°C or lower.

[0051] The volume average particle size of the low-melting-point metal particles is preferably 30 μm or less, more preferably 1 μm or more and 20 μm or less. When the volume average particle size of the low-melting-point metal particles is 30 μm or less, the volume ratio of the low-melting-point metal particles to the second metal particles can be reduced, and high thermal conductivity and low thermal resistance can be achieved in the low-melting-point metal particle-containing layer. The volume average particle size of the low-melting point metal particles can be measured in the same manner as the volume average particle size of the first metal particles.

[0052] The low-melting-point metal particle-containing layer preferably contains a component having flux activity, which can improve the wettability of the molten low-melting-point metal particles with the second metal particles.

[0053] Examples of the flux component include compounds having a protonic acid group such as a carboxy group, a sulfonyl group, or a phosphate group. Among these, compounds having a carboxy group are preferred, and polycarboxylic organic acids such as glutaric acid and succinic acid are more preferred. Compounds modified from glutaric anhydride or succinic anhydride, or metal salts of polycarboxylic organic acids such as silver glutarate, may also be used. The polycarboxylic acid also functions as a curing agent for the thermosetting resin, and therefore the curing agent is preferably a polycarboxylic acid.

[0054] The average thickness of the low-melting-point metal particle-containing layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm to 200 μm, more preferably 15 μm to 100 μm. When the average thickness is 10 μm or more, a sufficient amount of low-melting-point metal is alloyed with the metal layer, forming a heat conduction path with the second metal particles, resulting in excellent thermal conductivity. When the average thickness is 200 μm or less, a sufficient thermal resistance value can be obtained as a heat dissipation member. In addition, when the low-melting-point metal particle-containing layer fills at least a part of the openings of the adjacent metal layer and has protrusions within the openings, the thickness of the low-melting-point metal particle-containing layer in the region without the protrusions is measured without taking the protrusions into consideration. The average thickness can be calculated as the average value of the thicknesses at any three or more points.

[0055] [Laminate properties] The thermal conductivity of the laminate is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of thermal conductivity, however, it is preferably 15 W / (m·K) or more, more preferably 20 W / (m·K) or more, and even more preferably 25 W / (m·K) or more.

[0056] The average thickness of the laminate is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 20 μm to 500 μm, more preferably 30 μm to 300 μm, and even more preferably 40 μm to 250 μm.

[0057] The thickness ratio of the metal particle-containing layer, the metal layer, and the low-melting point metal particle-containing layer, when the total is 100, is preferably 10-60:5-60:10-50, and more preferably 10-50:10-50:10-50 (note that each value is an arbitrary value selected so that the total is 100).

[0058] The average thickness of the metal layer (T M ) to the average thickness (T1) of the metal particle-containing layer (T1 / T M) is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of improving thermal conductivity, it is preferably 0.2 or more and 10 or less, and more preferably 0.5 or more and 5 or less.

[0059] The average thickness of the metal layer (T M ) to the average thickness (T2) of the low-melting-point metal particle layer (T2 / T M ) is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of improving thermal conductivity, it is preferably 0.2 or more and 8 or less, more preferably 0.5 or more and 4 or less.

[0060] (Method of manufacturing laminate) The method for producing the laminate is not particularly limited and can be appropriately selected depending on the purpose. A method for producing a laminate according to one embodiment includes a metal particle-containing layer forming step and a low-melting-point metal particle-containing layer forming step, and may further include other steps such as a metal layer forming step, as necessary. As long as a laminate having a metal particle-containing layer, a metal layer, and a low-melting point metal particle-containing layer in this order can be formed, the metal particle-containing layer may be laminated on one side of the metal layer and then the low-melting point metal particle-containing layer may be laminated on the other side of the metal layer, the low-melting point metal particle-containing layer may be laminated on one side of the metal layer and then the metal particle-containing layer may be laminated on the other side of the metal layer, or the metal particle-containing layer may be placed on one side of the metal layer and the low-melting point metal particle-containing layer may be placed on the other side of the metal layer, and both may be laminated simultaneously.

[0061] <Metal particle-containing layer lamination process> The metal particle-containing layer laminating step is a step of laminating a metal particle-containing layer on a metal layer having a plurality of openings. For example, examples include a step of placing and adhering a sheet-like metal particle-containing layer on a metal layer; and a step of applying a composition for forming a metal particle-containing layer (sometimes referred to as a "metal particle-containing composition") on the metal layer to form a metal particle-containing layer. The metal particle-containing composition contains first metal particles and a first resin, and may further contain other components such as a solvent, as necessary. Each component may be appropriately selected from the components described above for the metal particle-containing layer.

[0062] The sheet-like metal particle-containing layer can be formed, for example, by applying a metal particle-containing composition to a release-treated substrate and removing the solvent by a solvent removal treatment (e.g., heating at 50°C to 90°C for 1 minute to 30 minutes). Next, a sheet-like metal particle-containing layer is placed on the metal layer by means of transfer or the like, and then bonded and laminated by, for example, heat pressing at 0.1 MPa to 1 MPa, 50°C to 90°C, and for 10 seconds to 30 minutes, thereby forming a laminate intermediate (or laminate) in which the metal layer and the metal particle-containing layer are integrated.

[0063] Alternatively, a metal particle-containing composition can be applied directly onto the metal layer, and then bonded by, for example, solvent removal treatment and heat pressing, to form a laminate intermediate (or laminate) in which the metal layer and the metal particle-containing layer are integrated.

[0064] Examples of methods for applying the metal particle-containing composition include inkjet coating, blade coating, gravure coating, gravure offset coating, bar coating, roll coating, knife coating, air knife coating, comma coating, U comma coating, AKKU coating, smoothing coating, microgravure coating, reverse roll coating, four-roll coating, five-roll coating, dip coating, curtain coating, slide coating, and die coating.

[0065] <Low-melting-point metal particle-containing layer lamination process> The low-melting-point metal particle-containing layer laminating step is a step of laminating a low-melting-point metal particle-containing layer on a metal layer having a plurality of openings. Specifically, examples of such processes include a step of placing and adhering a sheet-like low-melting-point metal particle-containing layer on a metal layer; and a step of applying a composition for forming a low-melting-point metal particle-containing layer (sometimes referred to as a "low-melting-point metal particle-containing composition") on the metal layer to form a low-melting-point metal particle-containing layer. The low-melting-point metal particle-containing composition contains low-melting-point metal particles, second metal particles, and a second resin, and may further contain other components such as a solvent, as necessary. Each component can be appropriately selected from the components described above for the low-melting-point metal particle-containing layer.

[0066] A sheet-like low-melting-point metal particle-containing layer can be formed, for example, by applying a low-melting-point metal particle-containing composition to a release-treated substrate and removing the solvent by a solvent removal treatment (e.g., heating at 50°C to 90°C for 1 minute to 30 minutes). Next, a sheet-like low-melting-point metal particle-containing layer is placed on the metal layer by means of transfer or the like, and then bonded and laminated by, for example, heat pressing at 0.1 MPa to 1 MPa, 50°C to 90°C, and for 10 seconds to 30 minutes, thereby forming a laminate intermediate (or laminate) in which the metal layer and the low-melting-point metal particle-containing layer are integrated.

[0067] Alternatively, a low-melting-point metal particle-containing composition can be directly applied onto the metal layer, and then bonded by, for example, solvent removal treatment and heat pressing, to form a laminate intermediate (or laminate) in which the metal layer and the low-melting-point metal particle-containing layer are integrated.

[0068] Examples of methods for applying the low-melting-point metal particle-containing composition include inkjet coating, blade coating, gravure coating, gravure offset coating, bar coating, roll coating, knife coating, air knife coating, comma coating, U-comma coating, AKKU coating, smoothing coating, microgravure coating, reverse roll coating, four-roll coating, five-roll coating, dip coating, curtain coating, slide coating, and die coating.

[0069] <Other processes> The other steps are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a metal layer forming step and a substrate laminating step.

[0070] <<Metal layer formation process>> The metal layer forming step is a step of forming a metal layer by forming a plurality of openings in a metal plate or metal foil. Further, the surface may be treated with one or more metals selected from the group consisting of copper, silver, gold, tin, and nickel. The openings may be formed by, for example, etching. Examples of the surface treatment method include electroless plating.

[0071] <<Base material lamination process>> The base material bonding step is a step of bonding the substrate and / or the opposing substrate to the laminate. Examples of lamination methods include a method in which a laminate is placed between a substrate and an opposing substrate and then lamination processing is performed; and a method in which a laminate is placed between a substrate or opposing substrate and a lamination substrate (a release-treated substrate or a substrate of a heat press device) and then lamination processing is performed. The lamination method is not particularly limited as long as the conditions are such that the metal particles are sintered and the low-melting-point metal particles contained in the low-melting-point metal particle-containing layer are melted and solidified to form a thermal path, and can be appropriately selected depending on the purpose. For example, a temperature of 120°C to 190°C for 1 minute to 30 minutes is preferred, and a temperature of 140°C to 170°C for 1 minute to 10 minutes is more preferred.

[0072] -Base material- The shape, structure, size, material, etc. of the substrate are not particularly limited and can be appropriately selected depending on the purpose. Examples of the shape of the substrate include a plate shape, a sheet shape, etc. Examples of the structure of the substrate include a single-layer structure, a laminated structure, etc. The size of the substrate can be appropriately selected depending on the application, etc.

[0073] As the material of the substrate, a material that is difficult for solder to wet can be selected because the metal particle-containing layer in contact with the substrate does not contain a low-melting point metal, and suitable examples include silicon, aluminum, tungsten, molybdenum, glass, molded resin, stainless steel, and ceramics. Examples of the ceramics include aluminum nitride, silicon carbide, alumina, and gallium nitride. Examples of the molding resin include epoxy resin, silicone resin, urethane resin, and acrylic resin. The substrate is preferably a silicon substrate.

[0074] The average thickness of the substrate is not particularly limited and can be appropriately selected depending on the purpose. The substrate may be the heat generating element (electronic component) itself in the heat dissipation structure.

[0075] <Facing substrate> The opposing substrate is disposed opposite the substrate, and its shape, structure, size, material, etc. are not particularly limited and can be appropriately selected depending on the purpose. Examples of the shape of the opposing substrate include a plate shape, a sheet shape, etc. Examples of the structure of the opposing substrate include a single-layer structure, a laminated structure, etc. The size of the opposing substrate can be appropriately selected depending on the application, etc. The material of the opposing substrate is a material that is easily wetted by solder, and includes at least one selected from copper, gold, platinum, palladium, silver, zinc, iron, tin, nickel, magnesium, indium, and alloys thereof. The average thickness of the opposing substrate is not particularly limited and can be appropriately selected depending on the purpose. The opposing substrate may be the heat spreader itself in the heat dissipation structure.

[0076] (Semiconductor packages, heat dissipation structures) The semiconductor package of this embodiment includes an integrated circuit member, a heat dissipation member, and the laminate of this embodiment described above between the integrated circuit member and the heat dissipation member, and may further include other members as necessary. The heat dissipation structure of this embodiment includes a heat generating element, the laminate of this embodiment described above, and a heat dissipation member, and may further include other members as necessary. The heat dissipation structure includes the laminate between the heat generating element and the heat dissipation member. The heat dissipation structure may further include an adhesive layer between each of the constituent members, if necessary. The semiconductor package is one aspect of the heat dissipation structure, and the integrated circuit member is one aspect of the heat generating body.

[0077] The heating element is not particularly limited and can be appropriately selected depending on the purpose. Examples include electronic components such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), and a GPU (Graphics Processing Unit).

[0078] The heat dissipation member is not particularly limited as long as it is a structure that dissipates heat generated by electronic components (heat generating elements), and can be appropriately selected depending on the purpose. Examples include a heat spreader, a heat sink, a vapor chamber, and a heat pipe. The heat spreader is a member for efficiently transferring heat from the electronic component to other components. The material of the heat spreader is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include copper and aluminum. The heat spreader is usually in a flat plate shape. The heat sink is a member for releasing heat from the electronic component into the air. The material of the heat sink is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include copper and aluminum. The heat sink has, for example, a plurality of fins. The heat sink has, for example, a base portion and a plurality of fins extending in a non-parallel direction (for example, a direction perpendicular to) one surface of the base portion. The heat spreader and the heat sink are generally solid structures with no internal voids. The vapor chamber is a hollow structure. A volatile liquid is sealed in the internal space of the hollow structure. Examples of the vapor chamber include a hollow heat spreader and a hollow plate-like structure similar to the heat sink. The heat pipe is a hollow structure having a cylindrical, approximately cylindrical, or flattened cylindrical shape, and a volatile liquid is sealed in the internal space of the hollow structure.

[0079] 7 is a schematic cross-sectional view showing an example of a semiconductor device as a heat dissipation structure. The laminate 7 of this embodiment dissipates heat generated by an electronic component 3 such as a semiconductor element, and as shown in FIG. 7, is fixed to the main surface 2a of the heat spreader 2 facing the electronic component 3, and is sandwiched between the electronic component 3 and the heat spreader 2. A thermally conductive sheet 1 is sandwiched between the heat spreader 2 and a heat sink 5. The thermally conductive sheet 1 may be the laminate of this embodiment or another thermally conductive sheet.

[0080] The heat spreader 2 is formed, for example, in the shape of a rectangular plate, and has a main surface 2a facing the electronic component 3 and side walls 2b erected along the outer periphery of the main surface 2a. The heat spreader 2 has a thermally conductive sheet 1 provided on the main surface 2a surrounded by the side walls 2b, and a heat sink 5 provided on the other surface 2c opposite the main surface 2a via the thermally conductive sheet 1. The higher the thermal conductivity of the heat spreader 2, the lower the thermal resistance and the more efficiently it absorbs heat from the electronic component 3, such as a semiconductor element. Therefore, the heat spreader 2 can be formed using, for example, copper or aluminum, which have good thermal conductivity.

[0081] The electronic component 3 is, for example, a semiconductor element such as a BGA, and is mounted on the wiring board 6. The tip surface of the side wall 2b of the heat spreader 2 is also mounted on the wiring board 6, so that the side wall 2b surrounds the electronic component 3 at a predetermined distance. Then, by providing the laminate 7 of this embodiment on the main surface 2a of the heat spreader 2, a heat dissipation member that absorbs heat generated by the electronic components 3 and dissipates the heat from the heat sink 5 is formed. [Example]

[0082] The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples.

[0083] <Preparation of Metal Particle-Containing Layer> A composition for forming a metal particle-containing layer (metal particle-containing composition) was prepared according to the formulation shown in Table 1. The values ​​in Table 1 are in volume %. Each of the prepared compositions was blade coated onto a release-treated PET film, and after leaving it at 60°C for 10 minutes, it was further dried at 80°C for 5 minutes to remove the solvent, thereby preparing sheet-like metal particle-containing layers Nos. 1 to 5 with an average thickness of 70 μm.

[0084] <Preparation of Low-Melting-Point Metal Particle-Containing Layer> A composition for forming a layer containing low-melting-point metal particles (a composition containing low-melting-point metal particles) was prepared according to the formulation shown in Table 2. The values ​​in Table 2 are in volume %. Each of the prepared compositions was blade coated onto a release-treated PET film, and after leaving it at 60°C for 10 minutes, it was further dried at 80°C for 5 minutes to remove the solvent, thereby preparing sheet-shaped low-melting-point metal particle-containing layers Nos. 1 to 7 with an average thickness of 70 μm.

[0085] [Table 1]

[0086] [Table 2]

[0087] Details of each component in Tables 1 and 2 are as follows.

[0088] -Low melting point metal particles- Sn 42 Bi 58 (D 50 :5.9μm): Solder powder Sn 42 Bi 58 STC5 (Mitsui Mining & Smelting Co., Ltd., volume average particle size D 50 value: 5.9 μm, melting temperature: 137.2°C) Sn 72 Bi 28 (D 50 :5.9μm): Solder powder Sn 72 Bi 28 STC5 (Mitsui Mining & Smelting Co., Ltd., volume average particle size D 50 value: 5.9 μm, melting temperature: 138.0°C)

[0089] -Metal particles- ·Ag particles (D 50 : 1.9 μm): Ag-4-8F (manufactured by DOWA Electronics Co., Ltd., volume average particle size D 50 Value: 1.9 μm) ·Ag particles (D 50 : 2.7 μm): Ag-5-8F (manufactured by DOWA Electronics Co., Ltd., volume average particle size D 50 Value: 2.7 μm) Ag-coated Cu particles (D50 : 10 μm): 10% Ag coated Cu-HWQ 10 μm (Fukuda Metal Foil Powder Co., Ltd., D 50 Value: 9.9 μm, Silver content: 10.8% by volume Ag-coated Cu particles (D 50 : 20 μm): 10% Ag coated Cu-HQW 20 μm (Fukuda Metal Foil Powder Co., Ltd., D 50 Value: 17.6 μm, Silver content: 10.7% by mass

[0090] -Thermoplastic resin- YP-50: YP-50 (Nippon Steel Chemical & Material Co., Ltd., bisphenol A phenoxy resin, glass transition temperature (Tg): 84°C) FX293 (Nippon Steel Chemical & Material Co., Ltd., special skeleton phenoxy resin, glass transition temperature (Tg): 158°C)

[0091] -Thermosetting resin- EXA-850CRP: EPICLON® EXA-850CRP (DIC Corporation, bisphenol A epoxy resin) HP-4032D: EPICLON® HP-4032D (manufactured by DIC Corporation, naphthalene skeleton-containing epoxy resin) OXBP: ETERNACOLL (registered trademark) OXBP (manufactured by UBE Corporation, biphenyl skeleton-containing oxetane resin) OXT-121: Aron Oxetane OXT-121 (manufactured by Toagosei Co., Ltd., xylylene bisoxetane)

[0092] - Hardener - HXA9382HP: Novacure HXA9382HP (manufactured by Asahi Kasei Corporation, anionic microcapsule hardener) Glutaric acid (Tokyo Chemical Industry Co., Ltd.)

[0093] -Additives, solvents- Silane coupling agent: KBM-4803 (Shin-Etsu Chemical Co., Ltd., glycidyl group-containing silane coupling agent) Antioxidant: Adekastab AO-60 (ADEKA Corporation, hindered phenol antioxidant) Solvent: PGMEA (Kanto Chemical Co., Ltd.)

[0094] <Formation of Metal Layer Having Multiple Openings> A grid pattern was etched all over an oxygen-free copper foil having an average thickness of 20 μm, as shown in FIG. 8, to form a metal layer 1 having an average thickness of 20 μm, square opening dimensions of 0.5 mm × 0.5 mm, an opening pitch (center-to-center distance between adjacent openings) of 0.6 mm, and an opening ratio of 69.4%.

[0095] As shown in Table 3, metal layers 2 to 6 were formed in the same manner as metal layer 1, except that any one of the opening size, opening pitch, opening ratio, and average thickness was changed. The metal layer 4 was formed by plating the surface of the metal layer 3 with tin to an average thickness of 1.5 μm by electroless tin plating. Furthermore, an oxygen-free copper foil with an average thickness of 20 μm that was not subjected to pattern etching was used as the metal layer 6 .

[0096] [Table 3]

[0097] Example 1 <Production of laminate> The stack of metal layer 1 and low-melting-point metal particle-containing layer 1 was sandwiched between two release-treated PET films and heat-pressed at 70°C for 15 seconds under a pressure of 0.3 MPa using a press, thereby integrating the metal layer 1 and low-melting-point metal particle-containing layer 1. Thereafter, the metal particle-containing layer 1 was placed on the metal layer 1 side of the obtained integrated sheet, and the sheet was sandwiched between two release-treated PET films from above and below and heat-pressed in a press at 0.3 MPa, 65°C, and for 15 seconds to produce the laminate of Example 1, in which the metal particle-containing layer 1, metal layer 1, and low-melting-point metal particle-containing layer 1 were integrated in this order.

[0098] <Lamination to substrate> The laminate of Example 1 was cut into a 20 mm × 20 mm square, and the laminate was placed on a silicon wafer diced into a 20 mm × 20 mm square so that the metal particle-containing layer was in contact with the silicon wafer. The laminate was then heat-pressed at 0.3 MPa, 60°C, and 10 seconds using a press to bond the laminate to the silicon wafer. Thereafter, a tough-pitch copper disk having an average thickness of 1 mm and a diameter of 20 mm was placed on the low-melting-point metal particle-containing layer of the laminate, and the laminate was hot-pressed at 150°C and 0.3 MPa for 300 seconds using a press to bond the laminate between the silicon wafer as a substrate and the copper plate, thereby producing the structure of Example 1 having the substrate and the laminate.

[0099] Examples 2 to 12 The laminates and structures of Examples 2 to 12 were produced in the same manner as in Example 1, except that the combination of the metal particle-containing layer, the metal layer, and the low-melting-point metal particle-containing layer was changed as shown in Table 4.

[0100] (Comparative Examples 1 to 5) The laminates and structures of Comparative Examples 2 to 5 were produced in the same manner as in Example 1, except that the combinations of the metal particle-containing layer, the metal layer, and the low-melting-point metal particle-containing layer were changed as shown in Table 5.

[0101] <Evaluation> Next, the "thermal conductivity" and "reflow resistance" were evaluated as follows for the laminates and structures of Examples 1 to 12 and Comparative Examples 1 to 5. The results are shown in Tables 4 to 6.

[0102] <Thermal conductivity> <<Measurement of thermal conductivity>> Each structure produced by bonding each laminate to a substrate was used as a sample for evaluating thermal conductivity, and evaluation was carried out using a method in accordance with ASTM-D5470. Specifically, each evaluation sample was placed between copper rods of a thermal conductivity measuring device with a commercially available heat dissipation grease interposed therebetween, and the thermal resistance was measured. The thermal resistance of the laminate was then calculated by subtracting the thermal resistances of the silicon wafer, copper rod, and thermal grease used as the substrates from the measured values. The thermal conductivity of the laminate, W / (m·K), was then calculated by dividing the average thickness of the laminate measured beforehand by the thermal resistance. Thermal conductivity was evaluated according to the following criteria. The results are shown in Tables 4 to 6. [Evaluation criteria] ◎: Thermal conductivity is 25 W / m·K or higher. Good: Thermal conductivity is 20 W / m·K or more and less than 25 W / m·K. △: Thermal conductivity is 10 W / m·K or more and less than 20 W / m·K. ×: The thermal conductivity is less than 10 W / m·K, which is outside the practical range.

[0103] <Reflow resistance> <<Reflow test>> In accordance with JEDEC Level 3, each evaluation sample was subjected to moisture absorption treatment at a temperature of 30°C and a humidity of 60 RH% for 168 hours. Next, a reflow test was performed three times using a reflow device (HAS-6116: manufactured by Antom Co., Ltd.) that reproduces a solder reflow temperature with a peak temperature of 260°C, with a reflow temperature profile conforming to IPC / JED EC J-STD-020C.

[0104] <<Measurement of thermal conductivity after reflow>> The thermal conductivity after reflow was measured and calculated in the same manner as in <<Measurement of Thermal Conductivity>> above, except that each evaluation sample that had been subjected to the reflow test was used. The rate of change ({|k1-k0| / k0}×100, [%]) of thermal conductivity after reflow (k1) to thermal conductivity before reflow (k0) was calculated, and reflow resistance was evaluated according to the following criteria. The results are shown in Tables 4 to 6. [Evaluation criteria] ◎: The rate of change is 5% or less. Good: The rate of change is more than 5% and 10% or less. △: The rate of change is more than 10% and 15% or less. ×: The rate of change exceeds 15%, which is outside the practical range.

[0105] [Table 4]

[0106] [Table 5]

[0107] [Table 6]

[0108] The results in Tables 4 to 6 show that the laminates of Examples 1 to 12 have improved thermal conductivity and reflow resistance due to the presence of a metal layer having a plurality of openings. Furthermore, it was found that the laminates of Examples 1 to 12 were able to improve thermal conductivity by having a metal particle-containing layer and a low-melting point metal particle-containing layer, each of which contained metal particles, and that the low-melting point metal particle-containing layer was able to further improve thermal conductivity and reflow resistance by containing low-melting point metal particles.

[0109] Among the aperture ratios of metal layers having multiple openings, those with aperture ratios of 30% or more and 55% or less were found to have excellent thermal conductivity, and it was found that the laminate of Comparative Example 4, which had a metal layer 6 without openings, had poor reflow resistance and was outside the practical range. Furthermore, when a metal layer 4 in which Sn plating was further applied to a metal layer 3 having multiple openings was used (Example 8), it was found that the laminate had even better reflow resistance than the laminate in Example 7 having a metal layer 3. From the above, it was found that the laminates of the examples were able to achieve both high thermal conductivity and reflow resistance. [Explanation of symbols]

[0110] 1. Thermal conductive sheet 2 heat spreaders 2a Main surface 3 Heat generating elements (electronic components) 3a Top side 5 Heatsink 6. Wiring board 7 Laminate 10 Laminate 11 Metal particle containing layer 12 metal layer 12a opening 13 Low melting point metal particle containing layer

Claims

1. a metal particle-containing layer containing first metal particles and a first resin; a metal layer having a plurality of openings; a low-melting-point metal particle-containing layer containing low-melting-point metal particles, second metal particles, and a second resin, in this order; A laminate, characterized in that the first metal particles and the second metal particles contain one or more metals selected from the group consisting of copper, silver, gold, aluminum, zinc, platinum, and nickel.

2. The laminate according to claim 1 , wherein the metal layer contains one or more metals selected from the group consisting of copper, nickel, and aluminum.

3. The laminate according to claim 1 , wherein the metal layer is surface-treated with one or more metals selected from the group consisting of copper, silver, gold, tin, and nickel.

4. The laminate according to claim 1 , wherein the aperture ratio of the metal layer is 10% or more and 75% or less.

5. The laminate according to claim 1 , wherein the first resin comprises a thermosetting resin.

6. The laminate according to claim 1 , wherein the second resin comprises a thermosetting resin.

7. an integrated circuit member; A heat dissipation member; A semiconductor package comprising the laminate according to claim 1 between the integrated circuit member and the heat dissipation member.

Images