JPWO2011129232A1 - LED heat dissipation board - Google Patents

Abstract

In the present invention, a copper foil or a copper alloy foil is laminated on one surface of a polyimide film, and an aluminum foil or an aluminum alloy foil is laminated on the opposite surface, and the surface of the copper foil or the copper alloy foil and the aluminum foil or the aluminum alloy foil It is related with the thermal radiation board | substrate for LED whose thermal resistance between the surfaces is 1.8 degrees C / W or less.

Description

  The present invention relates to an LED heat dissipation substrate. In particular, the present invention relates to a heat dissipation substrate for LED that is thin, foldable, and three-dimensionally processable.

  In recent years, the demand for LED lighting devices using LEDs (light emitting diodes) as light sources has been rapidly expanding because of low power consumption and long life. However, the LED generates heat when the LED is turned on, and if the LED becomes hot due to the generated heat, the light emission efficiency of the LED is remarkably lowered, and the life of the LED may be affected. In particular, in a high-output / high-brightness LED, the amount of heat generated during lighting increases, so it is more important to dissipate the heat of the LED and suppress the temperature rise of the LED.

  Therefore, as a substrate for mounting the LED, a heat dissipation substrate with excellent heat dissipation is used. Generally, a copper foil is laminated on one side of an epoxy resin film, which is an insulating layer, and an aluminum foil is laminated on the opposite side. A heat dissipation board is used. However, when an epoxy resin film is used, it is necessary to use a film having a thickness of about 1 mm and at least about 100 μm from the standpoint of withstand voltage. In addition, since such a thick epoxy resin film has a large thermal resistance, it is necessary to reduce the thermal resistance by adding a large amount of an inorganic filler such as alumina having a high thermal conductivity in order to obtain sufficient heat dissipation. It is. However, the heat dissipation substrate for LED to which such an inorganic filler is added in a large amount is inferior in processability, and when machined, the filler may be scattered around and cause a problem. Moreover, this LED heat dissipation board cannot be bent and cannot be three-dimensionally processed. If three-dimensional processing becomes possible, the degree of freedom in circuit design is improved. Therefore, an LED heat dissipation substrate having good bending characteristics is required.

  In Patent Document 1, a substrate body in which a thermoplastic heat-resistant film using polyimide is molded into a predetermined three-dimensional shape, and one or a plurality of surface-mounted LEDs attached to the substrate body at predetermined positions, , An LED lighting device provided on either the front surface or the back surface of the substrate body, and having a conductive circuit for connecting the LED to an external circuit and lighting it, the surface opposite to the conductive circuit of the substrate body Further, an LED lighting device is disclosed in which a heat dissipation layer made of metal is formed.

  On the other hand, in Patent Document 2, a thin-layer polyimide (Y) having a specific imide unit on both surfaces of a low thermal expansion base polyimide (X) layer is laminated and integrated as a copper-clad plate having good thermal conductivity. A heat-resistant copper-clad plate is disclosed, in which a copper foil is laminated on one side of a multilayer polyimide film and a metal plate or ceramic plate having a good heat transfer property is laminated on the other side, and a metal plate having a good heat transfer property is disclosed. As an example, an aluminum plate having a thickness of 5 μm to 2 mm is cited.

  Patent Document 3 includes a copper or aluminum metal layer, a polyimide layer or an adhesive layer adjacent to the metal layer, a copper foil layer, and a liquid or film solder mask layer on the substrate. Laminates used for mounting and interconnecting LEDs are disclosed.

JP 2008-293692 A Japanese Patent Laid-Open No. 2003-71982 International Publication No. 2009/073670 Pamphlet

  An object of the present invention is to provide an LED heat dissipation substrate that has excellent heat dissipation and voltage resistance, is thin, has good bending characteristics, and can be three-dimensionally processed.

  The present invention relates to the following matters.

1. A heat dissipation substrate for LED in which a copper foil or a copper alloy foil is laminated on one side of a polyimide film and an aluminum foil or an aluminum alloy foil is laminated on the opposite side,
A heat dissipation substrate for LED, wherein the thermal resistance between the surface of the copper foil or copper alloy foil and the surface of the aluminum foil or aluminum alloy foil is 1.8 ° C./W or less.

  2. 2. The LED heat dissipation board according to 1 above, wherein the aluminum foil or aluminum alloy foil is not anodized (anodized).

  3. 3. The heat dissipation substrate for LED as described in 1 or 2 above, wherein the polyimide film has a thickness of 3 to 25 μm.

  4). The bonding surface of the polyimide film with a copper foil or a copper alloy foil, and the bonding surface with an aluminum foil or an aluminum alloy foil are thermocompression-bondable polyimide layers. LED heat dissipation board.

  5. 5. The LED heat dissipation substrate as described in 4 above, wherein the polyimide film is one in which a thermocompression bonding polyimide layer is laminated on both sides of a heat resistant polyimide layer.

6). The thickness of the copper foil or copper alloy foil is 9 to 200 μm,
6. The LED heat dissipation board as described in any one of 1 to 5 above, wherein the aluminum foil or the aluminum alloy foil has a thickness of 200 μm to 1 mm.

  7). The heat dissipation substrate for LED according to any one of the above 1 to 6, wherein a polyimide film, a copper foil or a copper alloy foil, and an aluminum foil or an aluminum alloy foil are bonded together by a pressure heating molding apparatus.

  Here, the thermal resistance between the surface of the copper foil or copper alloy foil and the surface of the aluminum foil or aluminum alloy foil (also referred to as the thermal resistance between the copper foil and the aluminum foil) is usually the thermal resistance of the polyimide film. The same value as

  The LED heat dissipation board of the present invention is obtained by laminating a copper foil or a copper alloy foil on one surface of a thin polyimide film and an aluminum foil or an aluminum alloy foil on the opposite surface. The thermal resistance between the surface of the foil and the surface of the aluminum foil or aluminum alloy foil is 1.8 ° C./W or less. Such an LED heat dissipation board is unprecedented, is thin, has good bending characteristics, and has excellent heat dissipation and voltage resistance.

  Since the polyimide film is excellent in insulation, a sufficient withstand voltage can be obtained even if the thickness is reduced. And since the polyimide film can be made very thin, the LED heat dissipation substrate of the present invention has a small total thickness, low thermal resistance, good heat dissipation, excellent machinability, and good bending properties. And can be processed three-dimensionally. The LED heat dissipation substrate of the present invention can be manufactured by a roll-to-roll method having excellent mass productivity.

  An aluminum foil or an aluminum alloy foil is generally anodized (anodized) for the purpose of improving adhesion. However, the anodized aluminum foil or aluminum alloy foil has a thick and relatively hard oxide film on the surface, for example, about 4 μm, and if this is used, the bending characteristics of the heat dissipation substrate for LED may deteriorate. is there. In the present invention, it is preferable to use an aluminum foil or an aluminum alloy foil that has not been anodized.

  The LED heat dissipation board of the present invention is one in which a copper foil or copper alloy foil is laminated on one side of a polyimide film, and an aluminum foil or aluminum alloy foil is laminated on the opposite side, and the surface of the copper foil or copper alloy foil And the surface of the aluminum foil or aluminum alloy foil have a thermal resistance of 1.8 ° C./W or less. The thermal resistance between the surface of the copper foil or copper alloy foil and the surface of the aluminum foil or aluminum alloy foil is preferably 1.2 ° C./W or less, more preferably 0.8 ° C./W or less. Particularly preferred is 0.6 ° C./W or less.

  Although the lower limit value of the thermal resistance between the surface of the copper foil or copper alloy foil and the surface of the aluminum foil or aluminum alloy foil is not particularly limited, for example, 0.1 ° C / W or more, and further 0.15 ° C / W or more In particular, it is preferably 0.2 ° C./W or more.

  In the present invention, it is preferable that copper foil or copper alloy foil, and aluminum foil or aluminum alloy foil are directly laminated on the polyimide film without using an adhesive or the like. Therefore, the bonding surface of the polyimide film with the copper foil or copper alloy foil and the bonding surface with the aluminum foil or aluminum alloy foil have a polyimide layer excellent in adhesion to these metals, preferably excellent adhesion to these metals. A thermocompression bonding polyimide layer is preferred. The polyimide film may be a single-layer polyimide film excellent in adhesion to these metals, particularly a single-layer thermocompression bonding polyimide film excellent in adhesion to these metals. Those with a polyimide layer with excellent adhesion to these metals on both sides, especially those with a thermocompression bonding polyimide layer with excellent adhesion to these metals on both sides of a heat-resistant polyimide layer It may be. From the viewpoint of excellent mechanical properties, it is preferable that a polyimide layer having excellent adhesion to these metals, preferably a thermocompression bonding polyimide layer, is laminated on both surfaces of the heat-resistant polyimide layer.

  In this invention, the polyimide film should just become a polyimide film after manufacture of the heat sink for LED, and the heat sink for LED of this invention is copper foil or copper alloy foil, and aluminum foil or aluminum alloy foil to a polyimide film. It is not limited to what was manufactured by laminating. For example, a solution of a polyimide precursor such as polyamic acid is cast on a copper foil or copper alloy foil, heat treated and imidized to form a polyimide film, and aluminum foil or aluminum alloy foil is laminated on the polyimide film by thermocompression bonding. And you may manufacture the thermal radiation board | substrate for LED of this invention.

  A method for manufacturing the polyimide film and the LED heat dissipation substrate will be described later.

  The copper foil or copper alloy foil used in the present invention is not particularly limited, but a copper foil, particularly a rolled copper foil or an electrolytic copper foil can be suitably used.

  The thickness of the copper foil or copper alloy foil is preferably 9 to 200 μm, and more preferably 18 to 200 μm. A copper foil or copper alloy foil having a thickness of 35 to 80 μm may be preferable. Generally, a thicker copper foil or copper alloy foil is suitable for high current applications.

  As copper foil or copper alloy foil, Rz which shows surface roughness is 3 micrometers or less, More preferably, it is 2 micrometers or less, Most preferably, it is 0.5-1.5 micrometers. When Rz is small, the surface of the copper foil or copper alloy foil may be used after surface treatment.

  Examples of such a copper foil include a rolled copper foil, an electrolytic copper foil, or a copper alloy foil thereof, and a rolled copper foil is particularly preferable.

  The aluminum foil or aluminum alloy foil used in the present invention is not particularly limited, and the aluminum alloy foil may be an alloy with another metal mainly composed of aluminum. Examples of the aluminum alloy foil include an aluminum alloy (Al—Mg alloy) containing magnesium as a main additive, for example, a JIS 5000 series such as a JIS 5052 alloy.

  In the present invention, an aluminum alloy foil containing at least aluminum and magnesium is preferable because it has good bending characteristics.

  The Al—Mg-based alloy can be used in any composition, but the magnesium content is 1.5 to 5% by mass, more preferably 2 to 3% by mass because the strength is excellent. preferable.

  As described above, an LED heat dissipation substrate having good bending characteristics and excellent workability can be obtained, so that it is not anodized or has a thin anodized layer (for example, less than 4 μm, or even 3 μm or less). In particular, it is preferable to use an aluminum foil or an aluminum alloy foil, preferably an anodized aluminum foil or an aluminum alloy foil. In addition, when anodized or thin anodized aluminum foil or aluminum alloy foil is used, excellent bending resistance can be obtained. Hard to happen.

  Further, an aluminum foil or aluminum alloy foil subjected to alternating current electrolytic treatment (KO treatment) using an alkaline electrolyte containing a surfactant, for example, a KO treatment plate manufactured by Furukawa Sky Co., Ltd. can also be used. It is preferable to use an aluminum foil or an aluminum alloy foil that has not been subjected to.

  In the aluminum foil or aluminum alloy foil, the surface on the side laminated with the polyimide film may be anodized (also referred to as alumite treatment or sulfuric acid alumite treatment) or KO treatment, but from the viewpoint of heat resistance and bendability. It is preferable to use an aluminum foil or aluminum alloy foil that has not been anodized or KO-treated.

  The surface of the aluminum foil or aluminum alloy foil bonded to the polyimide film is preferably treated with an organic solvent in order to remove the oil adhering to the production of the aluminum foil or aluminum alloy foil.

  The thickness of the aluminum foil or aluminum alloy foil is preferably 200 μm to 1 mm, more preferably 250 to 500 μm, and particularly preferably 300 to 400 μm. In general, a thinner aluminum foil or aluminum alloy foil is suitable for bending applications.

  In the present invention, a heat sink can be joined to an aluminum foil or an aluminum alloy foil to dissipate heat, and solderable aluminum foil or aluminum alloy foil, for example, Saplate (manufactured by Toyo Kohan Co., Ltd.) It becomes possible to solder directly by using.

  In this invention, when a polyimide film has a thermocompression bonding layer in the side which contacts metal foil (copper foil, aluminum foil), the thickness of the thermocompression bonding layer is the surface roughness of the adhesive surface with the polyimide film of metal foil. (Rzjis) or more is preferable. When the thickness of the thermocompression bonding layer is less than the surface roughness (Rzjis) of the metal foil, the peel strength between the polyimide film and the metal foil of the obtained heat dissipation substrate for LED may vary greatly depending on the location.

  Next, the polyimide film will be described.

  Although it does not specifically limit as a polyimide film, It is excellent in adhesiveness with copper foil and aluminum foil, Preferably it is thermocompression bonding, metal foils, such as laminated copper foil, can be etched, heat resistance, electricity Any material having excellent insulation and flexibility can be used. In addition, it is sufficient if it can sufficiently support the metal foil as required, and it is not greatly affected by the developer or the stripping solution for removing the photoresist layer used when forming the metal wiring if necessary. Anything is acceptable.

  As the polyimide film, a single layer or a multilayer film, sheet, or plate in which two or more layers are laminated can be used.

  Examples of the polyimide film include, but are not limited to, “Upilex (VT)” (trade name) manufactured by Ube Industries, Ltd.

  The thickness of the polyimide film is not particularly limited, but it is preferably as thin as sufficient electrical insulation performance is obtained, and is preferably 3 to 50 μm, more preferably 4 to 35 μm, more preferably 5 to 25 μm, and more preferably. Is preferably 7 to 15 μm, particularly preferably 9 to 15 μm.

  The thickness of the polyimide film is preferably 4 to 15 μm and more preferably 7 to 12.5 μm from the viewpoint of solder resistance, and further preferably 9 to 15 μm from the viewpoint of solder resistance and thermal resistance.

  In the present invention, at least one surface of the substrate is subjected to surface treatment such as corona discharge treatment, plasma treatment, chemical roughening treatment, physical roughening treatment, or surface treatment with a surface treatment agent such as a silane coupling agent. A film can be used. In the case of a single-layer thermocompression bonding polyimide film or when the thermocompression bonding polyimide layer of the film is directly bonded to a metal, it is usually unnecessary to perform a surface treatment with a surface treatment agent.

  The most common amino-functional silane coupling agents and epoxy-functional silane coupling agents, mercapto-functional silane coupling agents, and olefin-functional silane coupling agents are used as surface treatments for polyimide films. Various agents such as an agent and an acrylic functional silane coupling agent can be used.

  Specific examples of the silane coupling agent include vinyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, vinylphenyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane. 4-glycidylbutyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) butoxy) propyl-3 -Aminopropyltrimethoxysilane, imidazolesilane, triazinesilane, γ-mercaptopropyltrimethoxysilane and the like. As the surface treating agent for the polyimide film, silane coupling agents such as aminosilane and epoxysilane are preferable.

  Moreover, it replaces with a silane coupling agent, and the same effect is acquired also when it processes with a titanate coupling agent or a zirconate coupling agent.

  The surface treatment with the silane coupling agent can be performed according to a known method.

  Treated with a surface treatment agent such as a silane coupling agent (surface treatment) may mean that the surface treatment agent is contained as it is on the surface of the polyimide film, or polyimide or a polyimide precursor. Alternatively, these organic solutions may be contained in a state in which a chemical change or the like is caused by heating at 320 to 550 ° C., for example.

  When the polyimide film is difficult to handle because the rigidity of the substrate is small, for example, a rigid film or substrate that can be peeled off in a subsequent process can be attached to the back surface of the substrate.

  In the present invention, the polyimide film has a heat-resistant layer (Sa1) and a thermocompression-bonding and / or adhesive layer (Sa2) including an adhesive layer on both surfaces of the heat-resistant layer. What has the multilayer thermocompression bonding property and / or adhesiveness more than a layer can be used. Examples of the layer structure include Sa2 / Sa1 / Sa2, Sa2 / Sa1 / Sa2 / Sa1 / Sa2, and the like. Moreover, the layer (Sa2) single layer polyimide film which has thermocompression bonding property can also be used.

  The layer (Sa2) having a thermocompression bonding property and / or adhesion property of the polyimide film is used for bonding with the metal foil. This layer (Sa2) having thermocompression bonding and / or adhesion is a layer selected from a layer having thermocompression bonding and a layer having adhesion.

  In a multilayer polyimide film having two or more thermocompression bonding properties and / or adhesion properties, the thicknesses of the heat-resistant layer (Sa1) and the thermocompression bonding property and / or adhesion layer (Sa2) should be appropriately selected. Can do. However, in the present invention, as described above, the thickness of the outermost layer having thermocompression bonding and / or adhesion (Sa2) is equal to or greater than the surface roughness (Rzjis) of the adhesive surface of the metal foil to the polyimide film. Preferably, it is 0.5 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more. Moreover, it is preferable that the thickness (Sa2) which has thermocompression bonding property and / or adhesiveness is 3 micrometers or less.

  The heat dissipation substrate for LED of the present invention is obtained by laminating a copper foil or a copper alloy foil, a polyimide film (polyimide layer), and an aluminum foil or an aluminum alloy foil, and is not limited by the manufacturing method. .

  As a heat dissipation board for LED, a copper foil or a copper alloy foil is applied to one side of a polyimide film, an aluminum foil or an aluminum alloy foil is directly applied to the opposite side, or via an adhesive (thermocompression bonding material) and / or Or what was laminated by pressurization etc. can be used. In addition, a polyimide solution or a polyimide precursor solution (polyamic acid solution, etc.) to be a thermocompression bonding polyimide layer is applied to copper foil or copper alloy foil, and aluminum foil or aluminum alloy foil. It is also possible to use those obtained by laminating these and a polyimide film by heating or pressing. Apply a polyimide solution or polyimide precursor solution (polyamic acid solution, etc.) to be a thermocompression bonding polyimide layer to copper foil or copper alloy foil, heat-dry and imidize as necessary, then add aluminum foil or aluminum to this It is also possible to use an alloy foil obtained by laminating by heating or pressing.

  It is preferable that the polyimide film and the metal foil (copper foil, aluminum foil) are directly laminated. However, even if the surface of the polyimide film and the metal foil are pressurized, heated or heated under pressure, the pressure-bonding property is maintained. When it is low, it is preferable to laminate the polyimide film and the metal foil through an adhesive.

  When an adhesive or thermocompression bonding organic material or resin, or a polyimide film resin is applied to a polyimide film or metal foil, the application is performed by a commonly used method such as a roll coater, a slit coater, or a comma coater. It can be carried out.

  When laminating a metal foil and a polyimide film having an adhesive layer or a thermocompression bonding resin layer, or laminating a metal foil and a polyimide film having an adhesive layer or a thermocompression bonding resin layer, a heating device, pressurization These can be laminated | stacked using an apparatus or a pressurization heating apparatus. It is preferable to appropriately select the heating condition and the pressurizing condition depending on the material used. The lamination of the metal foil and the polyimide film is not particularly limited as long as it can be performed continuously or batchwise, but it is preferably performed continuously using roll lamination or a double belt press.

  As the polyimide film, a polyimide film excellent in heat resistance, electrical insulation and the like can be suitably used.

  As the polyimide film, a single-layer polyimide film may be used, or a polyimide film in which two or more layers of polyimide are laminated may be used. Moreover, the kind of polyimide is not particularly limited.

A polyimide film can be manufactured by a well-known method. For example, a single-layer polyimide film
(1) A method in which a polyamic acid solution, which is a polyimide precursor, is cast or applied onto a support and imidized;
(2) The polyimide solution can be obtained by casting or coating on a support and heating as required.

Two or more layers of polyimide film
(3) A polyamic acid solution, which is a polyimide precursor, is cast or coated on a support, and a polyamic acid solution, which is a second or more polyimide precursor, is sequentially applied to the upper surface of the polyamic acid layer. A method of casting or applying to, imidizing,
(4) A method in which a polyamic acid solution which is a precursor of two or more layers of polyimide is simultaneously cast or applied on a support and imidized;
(5) A method in which a polyimide solution is cast or coated on a support, and a polyimide solution of the second layer or more is sequentially cast or coated on the upper surface of the polyimide layer, and heated as necessary.
(6) A method in which two or more layers of polyimide solution are simultaneously cast or coated on a support and heated as necessary.
(7) It can be obtained by a method of laminating two or more polyimide films obtained in (1) to (6) directly or via an adhesive.

  In addition, a polyimide film can also be directly formed on a copper foil or copper alloy foil of an LED heat dissipation board, or an aluminum foil or aluminum alloy foil as a support.

  As the polyimide film, a polyimide film having three or more layers having thermocompression bonding polyimide layers (S2) on both sides of the heat resistant polyimide layer (S1) is preferably used. Examples of the layer structure of the multilayer polyimide film include S2 / S1 / S2, S2 / S1 / S2 / S1 / S2, and the like. A thermocompression-bonding polyimide layer (S2) single-layer polyimide film can also be used.

  In the polyimide film having thermocompression bonding, the thicknesses of the heat-resistant polyimide layer (S1) and the thermocompression bonding polyimide layer (S2) can be appropriately selected. However, in the present invention, as described above, the thickness of the outermost thermocompression bonding polyimide layer (S2) is preferably equal to or greater than the surface roughness (Rzjis) of the adhesion surface of the metal foil to the polyimide film, In the case of a polyimide film having a thermocompression bonding polyimide layer (S2) on both sides of the heat resistant polyimide layer (S1), the outermost thermocompression bonding polyimide layer (S2) is sufficiently thick by thermocompression bonding with a copper foil or an aluminum foil. It is sufficient that a good adhesion can be obtained, preferably 0.5 to 10 μm, more preferably 1 to 7 μm, and still more preferably 2 to 5 μm. The thickness of the thermocompression bonding polyimide layer (S2) is preferably 3 μm or less.

  Curling can be suppressed by providing thermocompression bonding polyimide layers (S2) having substantially the same thickness on both surfaces of the heat-resistant polyimide layer (S1).

  In the polyimide film having thermocompression bonding, the heat-resistant polyimide of the heat-resistant polyimide layer (S1) has at least one of the following features (1) to (4), particularly the following features (1) to ( 4) having at least two [(1) and (2), (1) and (3), combinations of (2) and (3), etc.], especially having all the following characteristics Can be suitably used.

  (1) In the case of a single polyimide film, the glass transition temperature is 300 ° C. or higher, preferably the glass transition temperature is 330 ° C. or higher, and more preferably cannot be confirmed.

(2) In the case of a single polyimide film, the linear expansion coefficient (50 to 200 ° C.) (MD) is close to the thermal expansion coefficient of a metal foil such as a copper foil laminated on the polyimide film. Specifically, the thermal expansion coefficient of the polyimide film is preferably 5 × 10 ^{−6 to} 28 × 10 ⁻⁶ cm / cm / ° C., and 9 × 10 ^{−6 to} 20 × 10 ⁻⁶ cm / cm / ° C. It is more preferable that it is 12 × 10 ⁻⁶ to 18 × 10 ⁻⁶ cm / cm / ° C.

(3) In the case of a single polyimide film, the tensile elastic modulus (MD, ASTM-D882) is 300 kg / mm ² or more, preferably 500 kg / mm ² or more, more preferably 700 kg / mm ² or more.

  (4) Preferably the thermal shrinkage rate is 0.05% or less.

  As the heat-resistant polyimide layer (S1), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), pyromellitic dianhydride (PMDA) and 3,3 ′, 4, Mainly an acid component mainly composed of components selected from 4′-benzophenonetetracarboxylic dianhydride (BTDA), and a component selected from paraphenylenediamine (PPD) and 4,4′-diaminodiphenyl ether (DADE). Polyimide synthesized from a diamine component can be used. 4,4'-diaminodiphenyl ether (DADE) can be partially or wholly replaced with 3,4'-diaminodiphenyl ether (DADE).

  As the heat-resistant polyimide layer (S1), for example, the following polyimide is preferable.

  (1) Manufactured from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), paraphenylenediamine (PPD) and optionally 4,4′-diaminodiphenyl ether (DADE) Polyimide. In this case, the PPD / DADE (molar ratio) is preferably 100/0 to 85/15.

  (2) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) and pyromellitic dianhydride (PMDA), paraphenylenediamine (PPD) and 4,4′-diamino Polyimide produced from diphenyl ether (DADE). In this case, the BPDA / PMDA (molar ratio) is preferably 15/85 to 85/15, and the PPD / DADE (molar ratio) is preferably 90/10 to 10/90.

  (3) A polyimide produced from pyromellitic dianhydride (PMDA), paraphenylenediamine (PPD) and 4,4'-diaminodiphenyl ether (DADE). In this case, the DADE / PPD (molar ratio) is preferably 90/10 to 10/90.

  (4) 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and pyromellitic dianhydride (PMDA), paraphenylenediamine (PPD) and 4,4′-diaminodiphenyl ether ( DADE). In this case, it is preferable that BTDA / PMDA (molar ratio) is 20/80 to 90/10, and PPD / DADE (molar ratio) is 30/70 to 90/10.

  Moreover, you may use another tetracarboxylic dianhydride and diamine in the range which does not impair the physical property of heat resistant polyimide.

  The synthesis of the heat-resistant polyimide of the heat-resistant polyimide layer (S1 layer) can be achieved by either random polymerization or block polymerization as long as the ratio of each component is finally within the above range. It can also be achieved by a method in which two types of polyamic acids are synthesized in advance, and the polyamic acid solution is mixed and then mixed under reaction conditions to obtain a uniform solution.

  The heat resistant polyimide can be manufactured as follows. First, using each of the above components, a substantially equimolar amount of a diamine component and an acid component (tetracarboxylic dianhydride) is reacted in an organic solvent to obtain a polyamic acid solution. A part of the polyamic acid solution may be imidized as long as a uniform solution state is maintained. The polyamic acid solution is used as a dope solution, and after forming a thin film of the dope solution, the thin film is heated to remove the solvent by evaporating the polyamic acid and imide cyclization of the polyamic acid. Can be produced.

  In the present invention, after laminating a thin film of a thermocompression bonding polyimide dope on a thin film of a heat resistant polyimide dope, both can be simultaneously imidized. In the present invention, the heat-resistant polyimide dope solution and the thermocompression bonding polyimide dope solution are coextruded, and after the heat resistant polyimide dope solution thin film and the thermocompression bonding polyimide dope solution thin film are laminated, It is also possible to imidize at the same time. This method will be described later.

  On the other hand, the thermocompression bonding polyimide of the thermocompression bonding polyimide layer (S2) is (1) a polyimide having thermocompression bonding with a metal foil. This thermocompression bonding polyimide is preferably a polyimide having thermocompression bonding property that can be laminated with a metal foil at a temperature not lower than the glass transition temperature of the thermocompression bonding polyimide and not higher than 400 ° C.

  The thermocompression bonding polyimide of the thermocompression bonding polyimide layer (S2) preferably further has at least one of the following features (2) to (5).

  (2) The peel strength between the metal foil and the polyimide (S2) is 0.7 N / mm or more, and the peel strength retention is 90% or more, even 95% or more, even after heat treatment at 150 ° C. for 168 hours. 100% or more.

  (3) The glass transition temperature is 130 to 330 ° C.

(4) The tensile elastic modulus is 100 to 700 Kg / mm ² .

(5) The linear expansion coefficient (50 to 200 ° C.) (MD) is 13 to 30 × 10 ⁻⁶ cm / cm / ° C.

The thermocompression bonding polyimide layer (S2) can be selected from various known thermoplastic polyimides. For example,
2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), pyromellitic acid dianhydride Anhydride (PMDA), 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride (BTDA), 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride, 4,4 ′ -A component selected from oxydiphthalic dianhydride (ODPA), p-phenylenebis (trimellitic acid monoester anhydride), 3,3 ', 4,4'-ethylene glycol dibenzoate tetracarboxylic dianhydride, etc. An acid component containing, preferably an acid component containing them as a main component,
1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 2,2-bis [4- (4- Aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl A diamine component having at least three benzene rings in the main chain, preferably including them as a main component, and optionally having a diamine component having one or two benzene rings in the main chain. Furthermore, the polyimide synthesize | combined from the diamine component to contain can be used.

  The thermocompression bonding polyimide is preferably 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. Product (s-BPDA), pyromellitic dianhydride (PMDA) and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 1,4-bis ( 4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene and 2,2-bis [4- (4-aminophenoxy) phenyl] propane A polyimide synthesized from a diamine component selected from the following can be used. This thermocompression bonding polyimide can contain a diamine component having one or two benzene rings in the main chain, a diamine component other than the above, and an acid component, if necessary.

  As the thermocompression bonding polyimide, in particular, a diamine component containing 80 mol% or more of 1,3-bis (4-aminophenoxybenzene) (hereinafter sometimes abbreviated as TPER), 3,3 ′, 4,4 Polyimides prepared from '-biphenyltetracarboxylic dianhydride (s-BPDA) and / or 2,3,3', 4'-biphenyltetracarboxylic dianhydride (a-BPDA) are preferred. In this case, s-BPDA / a-BPDA (molar ratio) is preferably 100/0 to 5/95. In addition, other tetracarboxylic dianhydrides, such as 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride or 2,3,6,7, as long as the physical properties of the thermocompression bonding polyimide are not impaired. -It may be replaced with naphthalenetetracarboxylic dianhydride.

  A thermocompression bonding polyimide can be manufactured as follows. First, each of the above-mentioned components is further reacted with another tetracarboxylic dianhydride and another diamine in an organic solvent in an organic solvent at a temperature of about 100 ° C. or less, particularly 20 to 60 ° C. Make a solution. Then, this polyamic acid solution is used as a dope solution, and after forming a thin film of the dope solution, the thin film is heated to remove the solvent by evaporating and heat the polyamic acid by imide cyclization. A pressure-sensitive adhesive polyimide can be produced.

  In addition, the polyamic acid solution produced as described above is heated to 150 to 250 ° C., or an imidizing agent is added and reacted at a temperature of 150 ° C. or less, particularly 15 to 50 ° C. to imide cyclization. After that, the solvent is evaporated or precipitated in a poor solvent to form a powder, and then this powder is dissolved in an organic solvent to obtain an organic solvent solution of thermocompression bonding polyimide.

  In order to obtain a thermocompression bonding polyimide, the amount of diamine (as the number of moles of amino group) used in the organic solvent is the total number of moles of acid anhydride (tetracarboxylic dianhydride and dicarboxylic anhydride). The ratio to the total number of moles of acid anhydride groups) is preferably 0.95 to 1.0, particularly 0.98 to 1.0, more preferably 0.99 to 1.0. When making it react using dicarboxylic acid anhydride, the usage-amount can be made into a ratio which is 0.05 or less as a ratio with respect to the molar amount of the acid anhydride group of tetracarboxylic dianhydride.

  In the production of the thermocompression bonding polyimide, when the molecular weight of the resulting polyamic acid is small, the adhesive strength of the laminate with the metal foil, that is, the heat dissipation substrate for LED of the present invention may be reduced.

  Further, for the purpose of limiting the gelation of polyamic acid, phosphorus stabilizers such as triphenyl phosphite and triphenyl phosphate are added in an amount of 0.01 to 1 weight with respect to the solid content (polymer) concentration during polyamic acid polymerization. % Can be added.

  For the purpose of promoting imidization, a basic organic compound can be added to the dope solution. For example, imidazole, 2-methylimidazole, 1,2-dimethylimidazole, 2-phenylimidazole, benzimidazole, isoquinoline, substituted pyridine and the like are 0.05 to 10% by weight, particularly 0.1 to 2% by weight based on the polyamic acid. % Can be added. Since these form a polyimide film at a relatively low temperature, they can be used to avoid imidation becoming insufficient.

  For the purpose of stabilizing the adhesive strength, an organoaluminum compound, an inorganic aluminum compound, or an organotin compound may be added to the polyamic acid solution for thermocompression bonding polyimide. For example, aluminum hydroxide, aluminum triacetylacetonate or the like can be added in an amount of 1 ppm or more, particularly 1 to 1000 ppm as an aluminum metal with respect to polyamic acid.

  The organic solvent used when producing the polyamic acid from the acid component and the diamine component is N-methyl-2-pyrrolidone, N, N-dimethyl for any of heat-resistant polyimide and thermocompression bonding polyimide. Examples include formamide, N, N-dimethylacetamide, N, N-diethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, N-methylcaprolactam, and cresols. These organic solvents may be used alone or in combination of two or more.

  Heat-resistant polyimide and thermocompression-bonding polyimide are dicarboxylic anhydrides, such as phthalic anhydride and its substitutes, hexahydrophthalic anhydride and its substitutes, succinic anhydride and its substitutes, etc. In particular, phthalic anhydride can be used.

The polyimide film having thermocompression bonding having the thermocompression bonding polyimide layer (S2) on one side or both sides of the heat resistant polyimide layer (S1) is preferably
(I) A dope solution of heat-resistant polyimide (S1) and a dope solution of thermocompression bonding polyimide (S2) are laminated in a thin film by a coextrusion-casting film forming method (also simply referred to as a coextrusion method). Or a method of obtaining a multilayer polyimide film by drying and imidization, or (ii) a self-supporting film obtained by casting a dope solution of heat-resistant polyimide (S1) on a support and drying it. It can be obtained by applying a thermocompression-bondable polyimide (S2) dope solution on one side or both sides of (gel film) and drying and imidizing it to obtain a multilayer polyimide film.

  As the coextrusion method, a method described in JP-A-3-180343 (Japanese Patent Publication No. 7-102661) can be used.

  An example of the production of a three-layer polyimide film having thermocompression bonding on both sides is shown.

  A polyamic acid solution of heat-resistant polyimide (S1) and a polyamic acid solution of thermocompression-bondable polyimide (S2) are formed by a three-layer coextrusion method, and the thickness of the heat-resistant polyimide layer (S1 layer) is 4 to 45 μm. Supply to a three-layer extrusion die so that the total thickness of the thermocompression bonding polyimide layer (S2 layer) is 1 to 20 μm, cast on a support such as a stainless steel mirror surface or a belt surface, and the support surface Cast on top. And this cast film is dried at 100-200 degreeC, and the polyimide film (A) of the self-supporting film which is a semi-hardened state or the dry state before it is obtained.

  Here, when a cast film is processed at a high temperature exceeding 200 ° C., there is a tendency that adhesiveness is lowered in the production of a polyimide film having thermocompression bonding. The semi-cured state or the state before it means that the film is in a self-supporting state by heating and / or chemical imidization.

  The polyimide film (A) of the self-supporting film preferably has about 25 to 60% by mass, particularly preferably 30 to 50% by mass of the solvent and generated water remaining. When raising the temperature of the self-supporting film to the drying / imidization temperature, it is preferable to raise the temperature within a relatively short time, for example, it is preferable to raise the temperature at a temperature increase rate of 10 ° C./min or more. It is.

  By increasing the tension applied to the self-supporting film during drying and imidization, the linear expansion coefficient of the finally obtained polyimide film (A) can be reduced.

  For example, following the drying step for obtaining the above-mentioned self-supporting film, at least a pair of both end edges of the self-supporting film are fixed with a fixing device that can move together with the self-supporting film continuously or intermittently. At a temperature higher than said drying temperature, preferably in the range 200-550 ° C., particularly preferably in the range 300-500 ° C., preferably 1-100 minutes, in particular 1-10 minutes, self The support film is dried and heat-treated. The film is sufficiently removed from the self-supporting film so that the content of volatile substances composed of an organic solvent and product water in the finally obtained polyimide film is preferably 1% by weight or less. Can be sufficiently imidized to form a polyimide film having thermocompression bonding on both sides.

  As a fixing device for the self-supporting film, for example, a belt-like or chain-like one provided with a large number of pins or gripping tools at regular intervals, a self-supporting film supplied continuously or intermittently is used. A device is preferable in which a pair is installed along both side edges in the longitudinal direction, and the film can be fixed while moving the film continuously or intermittently. In addition, the self-supporting film fixing apparatus described above is capable of expanding and contracting the film being heat-treated in the width direction or the longitudinal direction at an appropriate elongation or contraction ratio (particularly preferably about 0.5 to 5% expansion / contraction ratio). It may be a device capable of

  It should be noted that the polyimide film having thermocompression bonding on both sides produced in the above step is again preferably at a temperature of 100 to 400 ° C. under a low or no tension of 4N or less, particularly preferably 3N or less, Preferably, by performing heat treatment for 0.1 to 30 minutes, a polyimide film having thermocompression bonding on both surfaces particularly excellent in dimensional stability can be obtained.

  Moreover, the manufactured polyimide film which has thermocompression bonding on both surfaces can be wound up in a roll shape by an appropriate known method.

  Here, the film surface of the polyimide film on the side where the cast dope is in contact with the support is referred to as B surface, and the film surface on the side where the cast dope is not in contact with the support (air side) is referred to as A surface.

  Next, the manufacturing method of the heat dissipation board for LED using the polyimide film which has a thermocompression bonding polyimide layer (S2) on both surfaces of the above heat resistant polyimide layers (S1) as a polyimide film is demonstrated.

  For example, the heat dissipation substrate for LED is formed by laminating a metal foil, that is, a copper foil or a copper alloy foil, and an aluminum foil or an aluminum alloy foil directly or via an adhesive on both surfaces of the heat-resistant polyimide (S1). Can be manufactured.

  The LED heat dissipation board is preferably a polyimide film having a thermocompression bonding polyimide layer (S2) on both sides, and a thermocompression bonding polyimide layer (S2) and a metal foil, that is, a copper foil or a copper alloy foil, Aluminum foil or aluminum alloy foil can be directly laminated.

  More preferably, the LED heat dissipation board uses a polyimide film having the thermocompression-bondable polyimide layer (S2) on both sides, and a copper foil or A on the film surface (side A side) of the thermocompression-bondable polyimide layer (S2). It is preferable from the viewpoint of peel strength that the copper alloy foil is produced by directly laminating an aluminum foil or an aluminum alloy foil on the film surface (B surface side) of the thermocompression bonding polyimide layer (S2).

The following method can be mentioned as an example of the manufacturing method of LED heat dissipation board which laminated metal foil on both surfaces of the polyimide film which has thermocompression bonding property. That is,
1) A long metal foil (copper foil or copper alloy foil), a long polyimide film having thermocompression bonding properties, and a long metal foil (aluminum foil or aluminum alloy foil) in this order 3 The sheets are stacked and sent to a thermocompression bonding apparatus (heat pressurizing apparatus). At this time, using a preheater such as a hot-air supply device or an infrared heater, preheating is preferably performed at about 150 to 250 ° C., particularly at a temperature higher than 150 ° C. and lower than 250 ° C. for about 2 to 120 seconds in an in-line immediately before introduction. It is preferable.

  2) Using a pair of crimping rolls or a double belt press, the temperature of the thermocompression bonding zone is in the temperature range from 20 ° C to 400 ° C higher than the glass transition temperature of polyimide (S2), particularly 30 ° C above the glass transition temperature. The metal foil / polyimide / metal foil stack is thermocompression-bonded under pressure in the temperature range from 400 ° C. to a higher temperature.

3) Especially in the case of a double belt press, it is subsequently cooled under pressure in a cooling zone, and preferably cooled to a temperature that is 20 ° C. or more lower than the glass transition temperature of polyimide (S2), particularly 30 ° C. or more. And metal foil is laminated | stacked on both surfaces of a polyimide film, and this is wound up in roll shape.
Thereby, a roll-shaped heat dissipation substrate for LED can be manufactured.

  In this manufacturing method, by preheating before thermocompression bonding, occurrence of poor appearance due to foaming of the laminate after thermocompression bonding due to moisture contained in polyimide is prevented, or immersion in a solder bath when forming an electronic circuit Foaming at the time can be prevented, thereby preventing deterioration of the product yield. Although a method of installing the entire thermocompression bonding apparatus in a furnace is also conceivable, the thermocompression bonding apparatus is practically limited to a compact one and is not practical because it is limited by the shape of the LED heat dissipation board. Further, even if pre-heat treatment is performed in the outline, the polyimide absorbs moisture again before being laminated, and it becomes difficult to avoid poor appearance due to foaming of the laminated body after thermocompression bonding and a decrease in solder heat resistance.

  The double belt press can perform high temperature heating and cooling under pressure, and is preferably a hydraulic type using a heat medium.

  A polyimide film having a thermocompression bonding property on both sides and a metal foil can be suitably stacked at a take-up speed of 1 m / min or more by using a double belt press and laminating by thermocompression-cooling under pressure. In addition, it is long and has a width of about 400 mm or more, particularly about 500 mm or more, and has a high adhesive strength (that is, excellent peel strength between the metal foil and the polyimide layer), and the surface of the metal foil is substantially wrinkled. It is possible to obtain a metal foil laminated polyimide film (LED heat dissipation substrate) having an appearance that is so unacceptable that it is not recognized.

  In order to mass-produce LED heat dissipation substrates with good product appearance, one or more combinations of thermocompression bonding polyimide film and metal foil are supplied, and a protective material (that is, protective material) is provided between the outermost layer and the belt. Two sheets) are interposed, and it is preferable to laminate by thermocompression-cooling under pressure. As the protective material, any material can be used as long as it is non-thermocompressible and has good surface smoothness. For example, metal foil, particularly copper foil, stainless steel foil, aluminum foil, high heat resistant polyimide film (Ube Industries, Ltd.) The thing of thickness about 5-125 micrometers, such as the product made from a corporation | Co., Ltd. and Upilex S), is mentioned suitably.

  The LED heat dissipation board obtained in this way is formed by removing the copper foil or copper alloy foil by etching in part according to a known method to form a metal wiring, and mounting the LED chip on the side where the metal wiring is formed To do. The LED heat dissipation substrate of the present invention is excellent in heat dissipation, and even if a large number of LEDs are mounted on the substrate for LED lighting devices and LED backlights, it is possible to suppress an increase in LED temperature and a decrease in light emission efficiency.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

(Evaluation method)
(1) Peel strength: The peel strength between the polyimide film and the aluminum foil is measured under the conditions of 90 ° and a width of 5 mm in accordance with JIS C5016. The measurement sample uses a polyimide / aluminum foil laminate from which the copper foil has been peeled off. The peel strength is measured at three points: an initial stage where nothing is treated, a wet heat treatment (after 85 ° C./85% Rh · 1000 hours), and a solder heat resistance at 260 ° C./30 seconds.

(2) Solder heat resistance: Performed according to JIS C6481. The measurement sample is a polyimide / aluminum foil laminate from which the copper foil has been removed by etching. Evaluation of solder heat resistance is performed under conditions of 250 ° C. or 270 ° C. for 30 seconds, and after heat treatment, the presence or absence of foaming on the polyimide film side of the laminate is visually observed.
○: No foaming, ×: Foaming.

(3) Bending workability: As a measurement sample, a laminate of copper foil / polyimide / aluminum foil is used. The laminated body is bent so that the outer diameter is about 1.0 mm and the inner diameter is about 0.6 mm. Thereafter, the bent portion is returned and the presence or absence of cracks in the bent portion of the aluminum foil is visually observed. Bending is performed in two ways: when the copper foil surface is on the outside and when the copper foil surface is on the inside.
○: no crack, ×: crack

(Reference Example 1: Production of dope solution for heat-resistant polyimide S1)
A monomer concentration of paraphenylenediamine (PPD) and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) in N-methyl-2-pyrrolidone at a molar ratio of 1000: 998. It was added so that it might become 18% (weight%, the same shall apply hereinafter), and reacted at 50 ° C for 3 hours. The solution viscosity at 25 ° C. of the obtained polyamic acid solution was about 1680 poise.

(Reference Example 2: Production of dope solution for thermocompression bonding polyimide S2)
1,3-bis (4-aminophenoxy) benzene (TPE-R) and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) in N-methyl-2-pyrrolidone and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) was added at a molar ratio of 1000: 200: 800 to a monomer concentration of 18%, and triphenyl phosphate was added to the monomer. 0.5% by weight based on the weight was added and reacted at 40 ° C. for 3 hours. The solution viscosity at 25 ° C. of the obtained polyamic acid solution was about 1680 poise.

(Reference Examples 3 and 4: Production of thermocompression-bonding multilayer polyimide films A1 and A2)
Using a film forming apparatus provided with a three-layer extrusion die (multi-manifold die), the polyamic acid solution obtained in Reference Example 1 and Reference Example 2 was changed on the metal support by changing the thickness of the three-layer extrusion die. And dried continuously with hot air at 140 ° C. and then peeled to form a self-supporting film. The self-supporting film peeled off from the support is gradually heated from 150 ° C. to 450 ° C. in a heating furnace to remove the solvent and imidize, so that two kinds of long three-layer polyimide films having different thicknesses are used. Was wound up on a roll.

  The result of having evaluated the characteristic of the obtained three-layer polyimide film (layer structure: S2 / S1 / S2) is shown below.

(Thermo-compressible multilayer polyimide film A1)
Thickness configuration: 2.5 μm / 7.5 μm / 2.5 μm (total 12.5 μm).
-Glass transition temperature of S2 layer: 240 degreeC.
-Glass transition temperature of S1 layer: A clear temperature could not be confirmed at 300 ° C or higher.
-Linear expansion coefficient (50-200 degreeC): MD19ppm / degreeC, TD18ppm / degreeC.
・ Mechanical properties (Test method: ASTM D882)
1) Tensile strength: 520 MPa for MD and TD,
2) Elongation rate: MD, TD 90% each
3) Tensile modulus: MD, TD 7200 MPa each.
・ Electrical characteristics (Test method: ASTM D149)
1) Dielectric breakdown voltage: 4.9 kV.

(Thermo-compressible multilayer polyimide film A2)
Thickness configuration: 4 μm / 17 μm / 4 μm (total 25 μm).
-Glass transition temperature of S2 layer: 240 degreeC.
-Glass transition temperature of S1 layer: A clear temperature could not be confirmed at 300 ° C or higher.
-Linear expansion coefficient (50-200 degreeC): MD19ppm / degreeC, TD18ppm / degreeC.
・ Mechanical properties (Test method: ASTM D882)
1) Tensile strength: 520 MPa for MD and TD,
2) Elongation rate: MD, TD 100% each,
3) Tensile modulus: MD, TD 7200 MPa each.
・ Electrical characteristics (Test method: ASTM D149)
1) Dielectric breakdown voltage: 7.1 kV.

  These thermocompression-bonding multilayer polyimide films (A1, A2) are 12.5 μm and 25 μm in thickness, and are thinner than the epoxy resin film (thickness: 1.2 mm) used for conventional general LED heat dissipation substrates. Insulative properties were comparable.

  In the following examples, a copper foil was laminated on the A surface side of the polyimide film, and an aluminum foil was laminated on the B surface side of the polyimide film.

  The aluminum foil used what was processed with the organic solvent in order to remove the oil component adhering to the surface.

(Examples 1-3)
(Manufacture of heat dissipation board for LED)
Three layers of polyimide film A2 preheated by heating at 200 ° C. for 30 seconds in-line immediately before the double belt press, and an electrolytic copper foil (thickness: 18 μm, Rz = 0. 6 μm), and the other surface (B surface) was laminated with an untreated or surface-treated Al—Mg alloy foil (Furukawa Sky, A5052-H34, thickness: 300 μm) as shown in Table 1 and heated. Sent to the zone (maximum heating temperature: 330 ° C.), then sent to the cooling zone (minimum cooling temperature: 180 ° C.), pressure bonding pressure: 3.9 MPa, pressure bonding time 2 minutes, thermocompression bonding-cooled and laminated Then, a heat dissipation substrate for LED (width: 540 mm, length: 30 m) was manufactured and wound into a roll. Table 2 shows the results of evaluating the peel strength, solder heat resistance, and bending workability of the obtained LED heat dissipation board. Evaluation of solder heat resistance was performed at 250 ° C.

(Examples 4 to 5)
(Manufacture of heat dissipation board for LED)
Three layers of polyimide film shown in Table 3 preheated by heating with hot air of 200 ° C. for 30 seconds in-line immediately before the double belt press, and rolled copper foil (thickness: 35 μm, roughened) on one side (A side) of this polyimide film Grade, Rz = 1.2 μm), and an untreated Al—Mg alloy foil (manufactured by Furukawa Sky, A5052-H34, thickness: 300 μm) is laminated on the opposite side (B side) and heated zone (maximum heating) Temperature: 330 ° C.), then to the cooling zone (minimum cooling temperature: 180 ° C.), pressure bonding pressure: 3.9 MPa, pressure bonding time 2 minutes, continuously thermocompression-cooled and laminated, LED A heat dissipation substrate (width: 540 mm, length: 30 m) was produced and wound into a roll. Table 3 shows the results of evaluating the peel strength, solder heat resistance, and bending workability of the obtained LED heat dissipation board. Evaluation of solder heat resistance was performed at 250 ° C. and 270 ° C.

(Evaluation of thermal resistance)
The thermal resistance of the LED heat dissipation substrate manufactured in Example 4 and Example 5 was evaluated by the following method.

  First, the manufactured LED heat dissipation substrate was cut into a size of 1 cm × 1.5 cm. Next, the heat conductive grease was thinly applied to the copper water-cooled plate having an area of 10 cm × 10 cm and the aluminum foil side of the LED heat dissipation substrate, and both were pasted. Next, heat conductive grease was thinly applied to the copper foil side of the LED heat dissipation board and a transistor (2SC3258) having one side of 1 cm × 1.5 cm, and both were pasted. In order to measure the temperature Th of the outermost surface on the transistor side of the interface between the transistor and the LED heat dissipation board, and the temperature Tl of the outermost surface of the water cooling plate and the copper foil contact portion of the LED heat dissipation board on the water cooling plate side, A groove for inserting a thin thermocouple was provided in advance on the surface of the transistor and the water-cooled plate.

  As described above, a transistor / copper foil / polyimide film / Al—Mg alloy foil / water-cooled plate and a thin thermocouple were set using the manufactured heat dissipation substrate for LED.

  Next, a power P of 5 to 35 W was applied to the transistor, and after waiting for the thermocouple instruction to stabilize, Th and Tl were measured.

  The thermal resistance Rth was calculated from the following formula.

Rth = (Th−Tl) / P−2 × Rg
Here, Rg is the thermal resistance (0.35 ° C./W) for one layer of thermally conductive grease.

  As described above, when the thermal resistance of the LED heat dissipation board manufactured in Example 4 was determined, it was 0.22 ° C./W, which was a very good thermal resistance. Moreover, when the heat resistance of the LED heat dissipation board manufactured in Example 5 was calculated | required, it was 0.58 degreeC / W and was a favorable heat resistance.

(Example 6)
(Manufacture of heat dissipation board for LED)
Three layers of polyimide film A1 preheated by heating with 200 ° C. hot air for 30 seconds in-line immediately before the double belt press, electrolytic copper foil (thickness: 18 μm) on one side of this polyimide film A1, and Al— on the opposite side Mg alloy foil (Furukawa Sky, JIS5052-H32 (A5052-H32), thickness: 300 μm) is laminated and sent to the heating zone (maximum heating temperature: 330 ° C.), and then the cooling zone (minimum cooling temperature: 180). ° C), pressure bonding pressure: 3.9 MPa, pressure bonding time 2 minutes, continuously heat-bonded-cooled and laminated to produce LED heat dissipation substrate (width: 540 mm, length: 30 m), roll It was wound up into a shape. The obtained LED heat dissipation board is a double-sided metal foil laminate of copper foil / polyimide film A1 / Al-Mg alloy foil, whereas the conventional general LED heat dissipation board cannot be bent, It was foldable and had good bending properties.

(Evaluation of thermal resistance)
The thermal resistance of the LED heat dissipation substrate manufactured in Example 6 was evaluated by the same method as in Example 4. The thermal resistance was 0.24 ° C./W, which was a good thermal resistance.

  As described above, according to the present invention, it has excellent heat dissipation and voltage resistance, is thin and has good bending characteristics, and can be folded inward, outwardly, or three-dimensionally processed. An LED heat dissipation substrate can be obtained.

Claims (7)

A heat dissipation substrate for LED in which a copper foil or a copper alloy foil is laminated on one side of a polyimide film and an aluminum foil or an aluminum alloy foil is laminated on the opposite side,
A heat dissipation substrate for LED, wherein the thermal resistance between the surface of the copper foil or copper alloy foil and the surface of the aluminum foil or aluminum alloy foil is 1.8 ° C./W or less.   The heat dissipation substrate for LED according to claim 1, wherein the aluminum foil or the aluminum alloy foil is not anodized (anodized).   The heat dissipation substrate for LED according to claim 1, wherein the polyimide film has a thickness of 3 to 25 μm.   The joining surface with the copper foil or copper alloy foil of the polyimide film and the joining surface with the aluminum foil or aluminum alloy foil are thermocompression-bondable polyimide layers. The heat dissipation board for LED as described.   The heat dissipation substrate for LED according to claim 4, wherein the polyimide film is one in which a thermocompression bonding polyimide layer is laminated on both surfaces of a heat resistant polyimide layer. The thickness of the copper foil or copper alloy foil is 9 to 200 μm,
The thickness of the said aluminum foil or aluminum alloy foil is 200 micrometers-1 mm, The heat dissipation board for LED in any one of Claims 1-5 characterized by the above-mentioned.   The heat dissipation substrate for LED according to any one of claims 1 to 6, wherein the polyimide film, the copper foil or the copper alloy foil, and the aluminum foil or the aluminum alloy foil are bonded together by a pressure heating molding apparatus. .