JP2009203262A - Thermally conductive material, heat dissipation substrate using it, and manufacturing method of heat dissipation substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of greatly limited use of a conventional heat dissipation substrate which uses a crystalline resin and is hardly usable for a circuit board and the like requiring predetermined shock resistance, since the crystalline resin itself is hard and brittle. <P>SOLUTION: When a thermally conductive material 17 comprising an epoxy resin containing 40 vol.% or more of a crystalline epoxy resin, a curing agent, a flame-retardant epoxy resin in an amount of 3-15 vol.% of the total of the epoxy resin and the curing agent, an inorganic filler in an amount of 70-88 vol.% of the total of the epoxy resin, the curing agent, and the flame-retardant epoxy resin, and a flame-retardant assistant filler in amount of 0.6-3.5 vol% of the total of the epoxy resin and the curing agent, is used for a thermally conductive insulating layer 11, the heat dissipation substrate excellent in both of high thermal conductivity and high flame retardancy can be obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat conductive material used for various electronic parts that require heat dissipation, such as power semiconductors, high-performance semiconductors, and light-emitting elements whose heat generation density is improved for downsizing of electronic devices, and the like. The present invention relates to a heat dissipation substrate used and a manufacturing method thereof.

  Conventionally, as a heat dissipation substrate for mounting electronic components, a metal core substrate in which an insulating material layer is laminated on a metal plate to form a wiring pattern is often used. Next, a conventional metal core substrate will be described with reference to FIG.

  FIG. 5 is a cross-sectional view of a conventional heat dissipation substrate. In FIG. 5, an electrical insulating layer 2 is formed on the metal plate 1. A copper foil 3 is laminated on the electrical insulating layer 2. On top of this, the electronic component 5, the semiconductor 6, the terminal 7, etc. are mounted using the solder 4. Here, the higher the thermal conductivity of the electrical insulating layer 2, the more heat from the electronic component 5 and the semiconductor 6 can be transferred to the metal plate 1, and the temperature rise can be suppressed. As the electrical insulating layer 2, a mixture of resin and filler is often used.

  As a method for increasing the thermal conductivity, a method of using a material having a high thermal conductivity as the filler of the electrical insulating layer 2 or a method of improving the filling amount of the filler is often used. Further, increasing the thermal conductivity of the resin is also effective and will be described with reference to FIG. For example, it has been proposed to use a crystalline resin as a means for increasing the thermal conductivity of the resin.

  FIG. 6 is a schematic view of a change during a polymerization reaction of a monomer having a mesogenic group. As shown in FIGS. 6A to 6C, the monomers 9 having mesogenic groups 8 are intended to obtain electrical insulation and excellent thermal conductivity by polymerizing each other. However, in order to obtain high heat dissipation (or high thermal conductivity) using a crystalline resin, it is necessary to increase the crystallization rate of the crystalline resin. However, in the crystalline resin, the higher the crystallization rate, the more difficult the substrate is to be hard and brittle (they are bent without bending or are easily cracked or cracked). In addition, the resin itself is flammable, and it is difficult to impart flame retardancy to the substrate while maintaining crystallinity. Therefore, even if a heat dissipation substrate for mounting electronic components is produced using crystalline resin, Usage was greatly limited.

As prior art document information related to the invention of this application, for example, Patent Documents 1 and 2 are known.
Japanese Patent No. 3255315 JP-A-11-323162

  As described above, the conventional crystalline resin has limited properties for the heat dissipation substrate due to the characteristic properties of the crystalline resin (hard and brittle, easy to chip, easy to break, easy to burn, etc.).

  As a method of improving the strength, there is a method of blending a curing agent that easily takes a network structure, etc., but in the case of a crystalline epoxy resin, by forming a three-dimensional bond, the crystallinity is inhibited and high thermal conductivity is obtained. In many cases, it cannot be obtained.

  As a method for loading the flame retardancy, a method of converting an organic flame retardant or an inorganic flame retardant can be considered. However, when an organic flame retardant is blended with structurally different resins, crystallization is inhibited and the amount of addition is limited, so that flame retardancy cannot be achieved while maintaining crystallinity. In addition, in the case of an inorganic flame retardant, since the thermal conductivity of the flame retardant is low, a high thermal conductivity cannot be obtained if the amount is increased.

  The present invention solves the conventional problem, solves the problem that the crystalline resin is hard and brittle, and easily burns, and achieves both high thermal conductivity and robustness to the heat dissipation substrate using the crystalline resin, It aims at providing the heat conductive material which can give a flame retardance, the heat dissipation board using the same, and its manufacturing method.

  In order to solve the conventional problems, the present invention provides an epoxy resin containing 40 vol% or more of a crystalline epoxy resin, a curing agent, and a difficulty of 3 vol% or more and 15 vol% or less with respect to the epoxy resin and the curing agent. Inorganic filler of 70 vol% or more and 88 vol% or less with respect to the flammable epoxy resin, the epoxy resin, the curing agent and the flame retardant epoxy, and 0.6 vol% or more and 3.5 vol with respect to the epoxy resin and the curing agent. % Or less flame retardant auxiliary filler, and a heat conductive material.

  In this way, the flame retardant epoxy and the flame retardant auxiliary filler are similarly converted at a rate that does not cause crystallization to break down. Is to improve.

  According to the heat conductive material of the present invention and the heat dissipation substrate using the heat conductive material and the method of manufacturing the heat dissipation substrate, high heat conductivity required as a component mounting substrate in a high heat dissipation substrate using a crystalline resin as one component thereof. And imparts flame retardancy. As a result, the heat dissipation substrate can achieve both high heat dissipation and durability / flame resistance.

  And since it becomes difficult for stress to concentrate on a heat conductive material (or heat conductive insulating layer formed by hardening a heat conductive material), the adhesive force between the metal plate is also improved.

(Embodiment)
Hereinafter, the thermally conductive material and the heat dissipation substrate using the same in the embodiment of the present invention will be described. First, a heat dissipation board using the heat conductive material (or heat conductive resin) of the present invention will be described with reference to FIG.

  FIG. 1 is a cutaway view of a heat dissipation board in the embodiment. In FIG. 1, reference numeral 10 denotes a wiring pattern, which corresponds to a lead frame, copper foil or the like processed into a predetermined shape (or a predetermined wiring pattern shape). Reference numeral 11 denotes a heat conductive insulating layer, which will be described later with reference to FIG. 3 and the like (referred to as a heat conductive material 17 in FIG. 3). The heat conductive material forming the heat conductive insulating layer 11 is a heat conductive material composed of a crystalline epoxy resin, a curing agent, a flame retardant epoxy resin, an inorganic filler, and a flame retardant auxiliary filler. Constitute. Then, this heat conductive material is processed into a sheet shape to form a heat conductive insulating layer 11. A metal plate 12 is made of a metal material having excellent thermal conductivity such as copper or aluminum.

  In FIG. 1, a sheet-like thermally conductive insulating layer 11 in which a part or more of the wiring pattern 10 is embedded is fixed to the surface of the metal plate 12. Then, one surface of the wiring pattern 10 is exposed from the thermally conductive insulating layer 11. Then, an electronic component (not shown) is mounted on the exposed surface of the wiring pattern 10 in which a part or more is embedded in the heat conductive insulating layer 11.

  Next, the heat dissipation mechanism of the heat dissipation substrate of FIG. 1 will be described with reference to FIG. 2A and 2B are cross-sectional views illustrating the heat dissipation mechanism of the heat dissipation board in which the wiring pattern 10 is embedded. 2A and 2B, reference numeral 13 denotes an electronic component, which is a semiconductor that generates heat (for example, a power transistor or a power FET), a light emitting diode (LED), or the like. 14a and 14b are arrows.

  First, as shown in FIG. 2A, the electronic component 13 is mounted on the wiring pattern 10. 2A and 2B, the solder resist formed on the wiring pattern 10 is not shown (It is desirable to form a solder resist on the wiring pattern 10. This is because the solder resist is formed on the wiring pattern 10. By forming the solder resist, mounting solder (not shown) is prevented from spreading on the surface of the wiring pattern 10).

  Next, how the heat generated in the electronic component 13 mounted on the wiring pattern 10 is radiated will be described with reference to FIG. In FIG. 2B, an arrow 14b indicates a direction in which heat is transmitted (or radiated). The heat generated in the electronic component 13 spreads over a wide area (heat spread) through the wiring pattern 10 as indicated by the arrow 14b. The heat of the wiring pattern 10 is transmitted to the heat conductive resin layer 11 in which the wiring pattern 10 is partially embedded. The heat of the heat conductive insulating layer 11 is transmitted to the metal plate 12. In this way, the electronic component 13 is cooled. In addition, by fixing the metal plate 12 to a housing or chassis (both not shown) of the device, heat transmitted to the metal plate 12 is transmitted to the outside.

  By cooling the electronic component 13 in this way, it is possible to increase the efficiency of the electronic component 13 (for example, increase the amount of light in the case of an LED, increase the efficiency or reduce the size of the power supply circuit), increase the lifetime, and increase the reliability. 2A and 2B, a mounting portion (for example, solder, wire, bump for surface mounting, etc.) between the electronic component 13 and the wiring pattern 10 is not shown. Next, the thermally conductive material used for the heat dissipation substrate will be described.

  First, a crystalline epoxy resin, a curing agent, a flame retardant epoxy resin, an inorganic filler, and a flame retardant auxiliary filler are weighed and mixed according to the blending ratio.

  As the mixing device, a commercially available heat kneading device (for example, a planetary mixer or kneader, or a laboratory plast mill manufactured by Toyo Seiki Seisakusho Co., Ltd.) or a twin screw kneader is used. Note that a stirring blade of Σ type, Z type, hybrid type or the like may be attached as a stirring blade inside the kneading apparatus. Moreover, shapes other than a blade | wing can also be used. It is desirable to use a kneading apparatus that can be heated to a predetermined temperature by a heater or the like. By heating the kneading apparatus, the resin material that is in a solid state at room temperature can be dissolved (or liquefied), so that the affinity with other members can be increased.

  Here, as the inorganic filler, it is desirable to use at least one inorganic filler selected from alumina, aluminum nitride, boron nitride, silicon carbide, silicon nitride, magnesium oxide, and zinc oxide. By using such an inorganic filler having a high thermal conductivity, the thermal conductivity of the thermal conductive insulating layer 11 can be further increased. By setting the temperature of the crystalline epoxy resin within the melting temperature (for example, 50 to 200 ° C.), the melt viscosity of the crystalline epoxy resin can be kept low and the inorganic filler can be uniformly dispersed in the resin. .

  In addition, it is desirable to set it as more than the minimum liquefaction temperature of these members (above the minimum temperature which can maintain a liquefied state, for example, 100 degreeC or more). And it is easy to make it uniform by kneading above this minimum liquefaction temperature.

  When the curing accelerator is added, the temperature of the kneading apparatus (or the resin member set therein) is lowered one step so that the thermosetting reaction (or change with time) of the resin after the addition can be suppressed. In this way, a heat conductive material is produced.

  Moreover, other additives can be added as needed. For example, release agents such as plasticizers, acid amides, esters and paraffins, stress relieving agents such as nitrile rubber and butadiene rubber, organic flame retardants such as phosphate esters and melamine, antimony pentoxide, molybdenum oxide, boric acid Inorganic flame retardants such as zinc, tin oxide, barium metaborate, aluminum hydroxide, magnesium hydroxide, calcium aluminate, silane coupling agents, titanate coupling agents, coupling agents such as aluminum coupling agents, Colorants such as dyes and pigments, inorganic fibers such as glass fibers, boron fibers, silicon carbide fibers, alumina fibers and silica alumina fibers, organic fibers such as aramid fibers, polyester fibers and cellulose fibers, oxidation stabilizers, light Stabilizer, moisture resistance improver, thixotropy imparting agent, diluent, antifoaming agent, various other It fat, tackifiers, antistatic agents, lubricants, also be incorporated an ultraviolet absorber and the like.

  Next, the preforming of the heat conductive material will be described. The heat conductive insulating material thus produced is desirably formed into a shape that is easy to form, such as a sheet shape, a round bar shape, or a pellet shape, at the same time as being taken out from the kneading apparatus. By pre-molding the heat conductive insulating material into a sheet shape, a round bar shape, a pellet shape, or the like, the handleability of the heat conductive insulating material can be improved.

  Next, with reference to FIG. 3, a pre-formation (for example, a sheet-like molding example) of the heat conductive material will be described.

  3 to 4, the sheet shape is used, but a round bar shape or a pellet shape may be used. By using a round bar shape, the surface area of the heat conductive material can be reduced, and the change with time can be suppressed. Further, it is difficult to generate an air residue (also referred to as a void) at the interface with the metal plate 12 or the like during pressing. In addition, handling property and weighing property are improved by making it into a pellet form.

  FIG. 3 is a cross-sectional view for explaining the preforming (sheet shape) of the heat conductive insulating material. In FIG. 3, 15 is a film, 16 is a molding apparatus, and 17 is a thermally conductive material. In FIG. 3, the heat conductive material 17 is composed of at least a crystalline epoxy resin, an inorganic filler, a curing agent, and a flame retardant epoxy resin. Then, the heat conductive material 17 is set in the molding device 16 and is driven as indicated by an arrow 14 to be preformed into a sheet shape. At this time, the film 15 is sandwiched between the heat conductive material 17 and the molding device 16, so that the surface of the processed part of the molding device 16 (for example, a rotating part of the roll, etc.) Prevent dirt. The film 15 is left as a kind of surface protecting film 15 on the surface of the heat conductive material 17 formed into a sheet.

  As the film 15, a resin film such as PET whose commercially available surface is treated with silicon, water repellent, or released can be used. The thickness of the preliminarily formed heat conductive material 17 is preferably 0.02 mm or more and 5.00 mm or less. When the thickness is 0.02 mm or less, pinholes may occur in the heat conductive resin material 21. Moreover, when the thickness exceeds 5.00 mm, the heat dissipation as a heat sink may be affected. In addition, by heating the molding part (for example, pressure roll part) of the molding apparatus 16, the moldability of the heat conductive material 17 can be improved, and the thickness variation of the completed sheet can also be reduced. Then, by leaving the film 15 as a kind of protective sheet on the surface of the heat conductive material 17 which has been call-molded into a sheet shape, it is possible to prevent dirt such as dust from adhering.

  Also, coating using a coater or an extrusion molding machine can be used.

  A solvent may be added to adjust the viscosity.

  Moreover, you may knead | mix in the state previously melt | dissolved in the solvent.

  In addition, the manufacturing method is not limited to FIG.

  Next, how a heat dissipation substrate is manufactured using the sheet-shaped heat conductive material 17 will be described with reference to FIGS. 4A and 4B are cross-sectional views illustrating an example of a method for manufacturing a heat dissipation board. 4A and 4B, 18 is a press.

  First, as shown in FIG. 4A, a heat conductive material 17 from which the film 15 has been removed in advance is set between the metal plate 12 and the wiring pattern 10. The metal plate 12, the heat conductive material 17, and the wiring pattern 10 are sandwiched between forming devices 16 such as a press 18 and heated and pressed as indicated by an arrow 14. In addition, by setting a dirt prevention film 15 between the metal plate 12 and the molding device 16 or between the wiring pattern 10 and the press 18, the surface of the press 18 is stained with the heat conductive material 17. Absent. 4 (A) and 4 (B), a die set on the press 18 is not shown. Then, as shown by the arrow 14, the press 18 is fixed by pressing these members at a predetermined temperature.

  Thereafter, the press 18 is pulled away in the direction of the arrow 14 as shown in FIG. Thereafter, the film 15 is peeled off. In this manner, a heat dissipation substrate (a product equivalent to FIG. 1) is produced in which the wiring pattern 10 is exposed only on one surface thereof, and is embedded in the heat conductive insulating layer 11.

  By embedding the wiring pattern 10 in the heat conductive insulating layer 11 in this way, the contact area between the wiring pattern 10 and the heat conductive insulating layer 11 can be increased, and heat dissipation is improved. Further, by embedding, an effect of reducing the thickness of the wiring pattern 10 protruding from the surface of the heat conductive insulating layer 11 can be obtained. Thus, even when a lead frame having a thickness of 0.3 mm, for example, is used as the wiring pattern 10, the protrusion amount (or step) of the wiring pattern 10 from the heat conductive insulating layer 11 is obtained by embedding it in the heat conductive insulating layer 11. Is suppressed to 50 μm or less (preferably 20 μm or less, more preferably 10 μm or less). By suppressing the protruding amount in this way, it becomes easy to form the solder resist formed on the wiring pattern 10, the thickness of the solder resist can be made thin and uniform, and the heat dissipation property of the heat dissipation substrate is improved.

  Further, by embedding a part or more of the wiring pattern 10 in the heat conductive insulating layer 11, the connection strength between the wiring pattern 10 and the heat conductive insulating layer 11 is increased. Then, the tensile strength of the wiring pattern 10 can be increased (for the method of measuring the tensile strength, a method for evaluating the tensile strength of the copper foil in the printed wiring board and the like can be referred to).

  Next, the crystalline epoxy resin which is a member constituting the heat conductive material 17 will be individually described.

  Next, the crystalline epoxy resin will be described using (Chemical Formula 1) to (Chemical Formula 8).

(Chemical Formula 1) to (Chemical Formula 8) are structural formulas showing an example of a crystalline epoxy resin. In (Chemical Formula 1), X in the structural formula of the crystalline epoxy resin is S (sulfur) or O (oxygen), C (carbon), or none (short bond). R1, R2, R3, and R4 are CH ₃ , H, t-Bu, and the like. R1 to R4 may be the same. This resin having an epoxy group is also called a main agent.

  (Chemical Formula 2) shows the structural formula of the curing agent used for curing the crystalline epoxy resin. In the structural formula of (Chemical Formula 2), X is S (sulfur) O (oxygen) or a short bond. A polymer obtained by mixing the main component of (Chemical Formula 1) and the curing agent of (Chemical Formula 2) and polymerizing may also be called a crystalline epoxy resin.

  The ratio between the main agent and the curing agent is calculated from the epoxy equivalent. The curing agent also acts as a curing agent for the flame retardant epoxy resin. A curing agent other than (Chemical Formula 4) may be used as the curing agent. As the crystalline epoxy resin, those shown in (Chemical Formula 3) to (Chemical Formula 8) can also be used. The crystalline epoxy resins represented by (Chemical Formula 3) to (Chemical Formula 8) have a melting point of about 50 to 121 ° C. and a low dissolution viscosity (for example, the viscosity at 150 ° C. is 6 to 20 mPa · s). The effect of being easy to mix and disperse is obtained.

  Next, the ratio between the crystalline epoxy resin and the epoxy resin will be described. It is desirable that the crystalline epoxy resin is contained in an amount of 40 vol% or more with respect to the epoxy resin as the main agent. When the crystalline epoxy resin is less than 40 vol%, the crystallinity is hardly expressed. Moreover, there are few crystallized parts and a sufficient effect on the thermal conductivity and the like cannot be obtained.

  Next, the ratio of the flame retardant epoxy resin to the epoxy resin and the curing agent will be described. In the crystalline epoxy resin, the structural shape is largely attributed to crystallinity, and if there are many large substituents such as Br, the crystallinity is hindered. Further, in order to impart flame retardancy, an appropriate amount of flame retardant epoxy resin is required. The amount of the flame retardant epoxy resin is desirably in the range of 3 vol% or more and 15 vol% or less with respect to the amount of the epoxy resin and the curing agent. When it is 3 vol% or less, sufficient flame retardancy cannot be imparted. On the other hand, if it is more than 15 vol%, the crystallinity is not expressed and the heat conduction is lowered. This imparting flame retardancy can be realized even when the amount of the flame retardant epoxy resin is small by combining with the flame retardant aid filler.

  Further, the flame retardant auxiliary filler is preferably 0.6 vol% or more and 3.5 vol% or less with respect to the epoxy resin and the curing agent. Since the thermal conductivity of the flame retardant aid filler is low, when it exceeds 3.5 vol%, the thermal conductivity is drastically reduced. Moreover, if it is 0.6 vol% or less, flame retardancy (mixing effect with flame retardant epoxy resin and inorganic filler) cannot be imparted. As the flame retardant auxiliary filler, a hydroxyl compound, a boron compound, an antimony compound, a molybdenum compound, a metal oxide salt, or the like can be used. In particular, antimony trioxide is desirable because of its great flame retardant effect. The particle size of antimony trioxide is preferably as small as 0.1 to 20 μm (desirably 0.3 to 10.0 μm). If it is smaller than 0.1 μm, it is expensive and may be difficult to disperse in the heat conductive material 17. Further, when the particle diameter exceeds 20 μm, the surface of the heat conductive insulating layer 11 becomes rough, which may affect the adhesion with the wiring pattern 10 made of a lead frame or the like.

  The particle size of antimony trioxide may affect the hygroscopicity. Therefore, in the case of a heat dissipation substrate in which hygroscopicity is a problem, the smaller the particle size of antimony trioxide, the easier it is to absorb moisture. Therefore, when hygroscopicity is a problem, the particle size of antimony trioxide is desirably 0.1 μm or more. This is because fine antimony trioxide of less than 0.1 μm is highly hygroscopic.

  The particle size of antimony trioxide can be easily dispersed in an epoxy resin or the like by matching the particle size of the inorganic filler (particle size close to the inorganic filler particle size). In this case, when a plurality of inorganic fillers having different particle sizes (for example, large powder and small powder) are used in combination, small powder (for example, 0.2 to 0.6 μm) or large powder (for example, 1.0 to 10 .mu.m). 0 μm), it is desirable to have the same particle size as either one. By doing so, the dispersibility of these powders is enhanced.

  In addition, in the ratio of the inorganic filler and the total resin (herein, the total resin means the total of the epoxy resin including the crystalline epoxy resin, the curing agent, and the flammable epoxy resin, which corresponds to the resin binder), the inorganic filler is The range of 70-88 vol% (the resin binder is 30-12 vol%) is desirable. When the proportion of the inorganic filler is less than 70 vol%, the thermal conductivity of the thermally conductive insulating layer 11 formed by curing the thermally conductive material 17 may be reduced. It also affects flame retardancy. Moreover, when the ratio of an inorganic filler becomes larger than 88 vol%, the moldability of the heat conductive resin material 21 may be affected. Here, vol% means volume%.

  As the inorganic filler, alumina, aluminum nitride, boron nitride, silicon carbide, silicon nitride, magnesium oxide, zinc oxide, and the like are desirable from the viewpoint of thermal conductivity, insulation, and the like. It is also possible to combine these inorganic fillers. The average particle size of the inorganic filler 19 is preferably in the range of 0.1 μm to 100 μm. When the average particle size is 0.1 μm or less, the specific surface area becomes large, the kneading of the heat conductive material 17 becomes difficult, and the moldability of the heat conductive insulating layer 11 may be affected. On the other hand, if the thickness exceeds 100 μm, it is difficult to reduce the thickness of the thermally conductive insulating layer 11, which may affect the heat dissipation as a heat dissipation substrate and may affect the miniaturization of the product. In order to increase the filling rate of the inorganic filler 19, a plurality of kinds of inorganic fillers 19 having different particle size distributions may be selected and used in combination.

  In addition, as the wiring pattern 10, depending on the use of the heat dissipation board, when the thickness of the wiring pattern 10 requires a range of 0.002 to 0.10 mm, a copper foil is required, and a range of 0.10 to 1.00 mm is required. In this case, the lead frames can be used differently. As the lead frame member, it is desirable to use a material mainly composed of copper (for example, a material called tough pitch copper or oxygen-free copper). By mainly using copper, both high heat dissipation and low resistance can be achieved. Further, by embedding a part or more of the wiring pattern 10 in the heat conductive insulating layer 11, a step (thickness step) due to the wiring pattern 10 in the heat dissipation substrate can be reduced.

Example 1
Hereinafter, as Experiment 1, an epoxy resin containing 40 vol% or more of a crystalline epoxy resin, a curing agent, and a flame retardant epoxy resin of 3 vol% or more and 15 vol% or less with respect to the total of the epoxy resin and the curing agent; Inorganic fillers of 70 vol% or more and 88 vol% or less with respect to the epoxy resin, the curing agent, and the flame retardant epoxy, and 0.6 vol% or more and 3.5 vol% or less of the epoxy resin and the curing agent with respect to the inorganic filler. The result of having experimented about the heat conductive material 17 which consists of a fuel filler filler is shown.

  "YL6121H" made by Japan Epoxy Resin as crystalline epoxy-containing resin, "YX4000H" as epoxy resin, 4,4'-diaminobiphenyl, 4,4'-dihydroxybiphenyl ether as curing agent, Japan as flame retardant epoxy resin Brominated epoxy “BREN-S” manufactured by Kayaku, alumina as an inorganic filler, and antimony trioxide as a flame retardant auxiliary filler were prepared.

  “P-200” imidazole (amine adduct) manufactured by Japan Epoxy Resin as a curing accelerator is mixed and stirred, heated to a temperature at which the epoxy resin and curing agent melt, and mixed using a biaxial kneader. did. After mixing, it was molded into a shape corresponding to various tests and heat-cured under the conditions of 180 ° C. × 5 Hour to obtain a thermally conductive insulating layer 11.

  Next, an example of evaluating the flame retardancy will be described with reference to Table 1.

  "YL6121H" made by Japan Epoxy Resin as a crystalline epoxy-containing resin, "YX4000H" as an epoxy resin, 4-4 diaminobiphenyl, 4-4, dihydroxybiphenyl ether as a curing agent, and Nippon Kayaku as a flame retardant epoxy resin Brominated epoxy “BREN-S”, Zeon Kasei core-shell acrylate copolymer “F351” as a thermoplastic resin, alumina as an inorganic filler, and antimony trioxide as a flame retardant auxiliary filler were prepared.

  “P-200” imidazole (amine adduct) manufactured by Japan Epoxy Resin as a curing accelerator is mixed and stirred, heated to a temperature at which the epoxy resin and curing agent melt, and mixed using a biaxial kneader. did. After mixing, it was molded into a shape corresponding to various tests and heat-cured under conditions of 180 ° C. × 5 Hour.

  For flame retardant test, sample 1: 125 ± 5mm × 13 ± 0.5mm × 1.6mm, sample 2: 125 ± 5mm × 13 ± 0.5mm × 0.4mm, manufactured in the shape of UL94 Based on the flame retardancy test.

  After 10 seconds of flame contact, the flame was released and the combustion time (t1) until extinction was measured. After digestion, after 10 seconds of flame contact, the flame was released and the combustion time until extinction (t2) was measured.

  The sample was mixed under the condition that there were many flammable crystalline epoxy resins and few fillers, and the ratio of the flame retardant epoxy and the flame retardant auxiliary filler was changed.

  Addition of flame retardant epoxy and flame retardant aid filler improves flame retardancy (decreases thermal conductivity). Table 1 shows the results.

  Table 1 shows that 3 vol% or more and 15 vol% or less flame retardant epoxy resin with respect to the total of the epoxy resin and the curing agent, and 0.6 vol% or more with respect to the total of the epoxy resin and the curing agent. An example in which flame retardancy is added when a flame retardant auxiliary filler of 5 vol% or less and a flame retardant epoxy of 3 vol% or more and a flame retardant auxiliary filler of 0.6 vol% or more are mixed will be described.

  From Table 1, the flame retardancy can be added when 3 vol% or more of the flame retardant epoxy and 0.6 vol% or more of the flame retardant auxiliary filler are mixed.

  Next, an example of the measurement result of thermal conductivity will be described with reference to Table 2.

  A sample for measuring thermal conductivity was prepared in a disk shape of φ1 / 2 inch and t1 mm, and measurement was performed using a xenon laser flash manufactured by Bruker AXS.

  The sample was blended under the condition that there were many crystalline epoxy resins having a high thermal conductivity and a large amount of filler, and the ratio of the flame retardant epoxy and the flame retardant auxiliary filler was changed. Table 2 shows the results.

  A flame retardant epoxy resin of 3% or more is necessary to add flame retardancy, but adding a flame retardant epoxy resin decreases the thermal conductivity, and when added over 18%, the epoxy resin is crystalline. Can not be taken, and the thermal conductivity is extremely reduced.

  Next, the effect of the flame retardant aid filler will be described with reference to Table 3.

  Table 3 shows the results of the flame retardant aid filler.

  A flame retardant aid filler of 0.6% or more is necessary to add flame retardancy, but the addition of the flame retardant aid filler reduces the thermal conductivity (the amount of filler does not increase drastically). When added in an amount of 4.0% or more, the epoxy resin cannot take crystallinity, and the thermal conductivity is extremely lowered. From the above, it can be seen that 3.5 vol% or less is good.

  As described above, an epoxy resin containing 40 vol% or more of a crystalline epoxy resin, a curing agent, and a flame retardant epoxy resin of 3 vol% or more and 15 vol% or less with respect to the total of the epoxy resin and the curing agent, The inorganic filler of 70 vol% or more and 88 vol% or less with respect to the total of the epoxy resin, the curing agent and the flame retardant epoxy resin, and 0.6 vol% or more with respect to the total of the epoxy resin and the curing agent By using a heat conductive material 17 (or a heat conductive insulating layer 11 formed by curing the heat conductive material 17) comprising a flame retardant auxiliary filler of 3.5 vol% or less, high heat conduction in a heat dissipation substrate or the like. Realization and flame retardancy.

  By using a thermally conductive material 17 (or a thermally conductive insulating layer 11 formed by curing the thermally conductive material 17), a cured epoxy resin cured by reacting an epoxy resin and a curing agent has crystallinity. , To achieve both high thermal conductivity and flame resistance in heat dissipation substrates.

  Further, by using brominated epoxy (or brominated epoxy resin) as the flame retardant epoxy resin, the heat conductive material 17 (or the heat conductive insulating layer 11 formed by curing the heat conductive material 17), or these members Achieves high thermal conductivity and flame retardance in heat dissipation boards using heat. Brominated epoxy resin has excellent compatibility with other resins by selecting the molecular weight. Bleed-out (Bleed-out is the aggregation of various additives in the thermal conductive material 17 over time and pulverization on the surface. Phenomenon and phenomenon of “bleeding out” of low molecular resin and solvent generated around the cured product). In particular, by reducing bleed-out, heat dissipation and flame retardancy can be improved.

Further, by using a hardener having a divalent OH group and / or NH ₂ group, the heat conductive material 17 (or the heat conductive insulating layer 11 formed by curing the heat conductive material 17 is used. ) Reactivity and curability, or matching with flame retardants, etc., and achieves both high thermal conductivity and flame retardant properties in heat dissipation substrates.

  The inorganic filler is preferably an inorganic filler composed of at least one selected from alumina, aluminum nitride, boron nitride, silicon carbide, silicon nitride, magnesium oxide, and zinc oxide. This is because they have high thermal conductivity and flame retardancy.

  In addition, a flame-retardant auxiliary | assistant filler makes an antimony trioxide further raise a flame retardance.

  Further, an epoxy resin containing 40 vol% or more of a crystalline epoxy resin, a curing agent, a flame retardant epoxy resin of 3 vol% or more and 15 vol% or less with respect to the epoxy resin and the curing agent, the epoxy resin and the curing agent. And an inorganic filler of 70 vol% or more and 88 vol% or less with respect to the flame retardant epoxy, and a flame retardant auxiliary filler of 0.6 vol% or more and 2.5 vol% or less with respect to the total of the epoxy resin and the curing agent, A heat conductive insulating layer 11 (or a heat conductive insulating layer 11 formed by curing a heat conductive material 17), a metal plate 12 adhered to the heat conductive insulating layer 11, and the heat conductive insulating layer. By using a heat dissipation board composed of the wiring pattern 10 in which at least a part is embedded in the layer 11, both high thermal conductivity and flame retardancy are achieved in the heat dissipation board and the like.

  At least an epoxy resin containing 40 vol% or more of a crystalline epoxy resin preformed in a sheet form on the metal plate 12, a curing agent, and a difficulty of 3 vol% or more and 15 vol% or less with respect to the epoxy resin and the curing agent. A flame retardant epoxy resin, an inorganic filler of 70 vol% to 88 vol% with respect to the total of the epoxy resin, the curing agent and the flame retardant epoxy, and 0.6 vol% with respect to the epoxy resin and the curing agent The step of setting the heat conductive material 17 composed of the flame retardant aid filler of 2.5 vol% or less and the wiring pattern 10, the heat conductive material 17 on the metal plate 12, and the wiring pattern 10 is manufactured by the manufacturing method of the heat dissipation board including the step of integrating the heat dissipation board 10 and the heat dissipation board excellent in both high thermal conductivity and flame retardance.

  As described above, the power supply circuit of the PDP television (PDP is a plasma display panel) and the light emitting diode of the liquid crystal television are used by the thermally conductive material according to the present invention and the method of manufacturing the heat dissipation substrate and the heat dissipation substrate. It is possible to reduce the size and cost of a device that requires heat dissipation such as a backlight.

Cutaway view of heat dissipation board in the embodiment (A) (B) is sectional drawing explaining the heat dissipation mechanism of the heat dissipation board | substrate which embedded both the wiring patterns. Sectional drawing explaining pre-formation (sheet form) of heat conductive insulating material (A) (B) is sectional drawing explaining an example of the manufacturing method of a heat sink. Sectional view of a conventional heat dissipation board Schematic diagram of changes during polymerization of monomers with mesogenic groups

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wiring pattern 11 Thermal conductive insulating layer 12 Metal plate 13 Electronic component 14 Arrow 15 Film 16 Molding apparatus 17 Thermal conductive material 18 Press

Claims (9)

An epoxy resin containing 40 vol% or more of a crystalline epoxy resin;
A curing agent;
3 vol% or more and 15 vol% or less flame retardant epoxy resin with respect to the total of the epoxy resin and the curing agent;
Inorganic filler of 70 vol% or more and 88 vol% or less with respect to the total of the epoxy resin, the curing agent and the flame retardant epoxy resin,
0.6 vol% or more and 3.5 vol% or less flame retardant aid filler with respect to the total of the epoxy resin and the curing agent;
Thermally conductive material consisting of The thermally conductive material according to claim 1, wherein the crystalline epoxy resin contained in the epoxy resin has the following structural formula.

The thermally conductive material according to claim 1, wherein the cured epoxy resin obtained by reacting the epoxy resin with the curing agent has crystallinity. The heat conductive material according to claim 1, wherein the flame retardant epoxy resin is a brominated epoxy. The thermally conductive material according to claim 1, wherein the curing agent has a divalent OH group and / or an NH ₂ group. The thermally conductive material according to claim 1, wherein the inorganic filler is an inorganic filler made of at least one selected from alumina, aluminum nitride, boron nitride, silicon carbide, silicon nitride, magnesium oxide, and zinc oxide. The heat conductive material according to claim 1, wherein the flame retardant auxiliary filler is antimony trioxide. An epoxy resin containing 40 vol% or more of a crystalline epoxy resin, a curing agent,
3 vol% or more and 15 vol% or less flame retardant epoxy resin with respect to the epoxy resin and the curing agent, and 70 vol% or more and 88 vol% or less inorganic filler with respect to the epoxy resin, the curing agent or the flame retardant epoxy A thermally conductive insulating layer comprising a flame retardant aid filler of 0.6 vol% or more and 2.5 vol% or less with respect to the total of the epoxy resin and the curing agent;
A metal plate adhered to the thermally conductive insulating layer;
A heat dissipation board comprising: a wiring pattern in which at least a part is embedded in the thermally conductive insulating layer. At least on a metal plate,
An epoxy resin containing 40 vol% or more of a crystalline epoxy resin preformed into a sheet, a curing agent, a flame retardant epoxy resin of 3 vol% or more and 15 vol% or less with respect to the epoxy resin and the curing agent, and the epoxy 70 to 88 vol% inorganic filler with respect to the total of the resin, the curing agent and the flame retardant epoxy, and 0.6 to 3.5 vol% with respect to the epoxy resin and the curing agent. A thermally conductive material comprising a fuel filler filler;
A step of setting a wiring pattern;
Integrating the thermally conductive material and the wiring pattern on the metal plate;
The manufacturing method of the thermal radiation board | substrate containing this.

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