JP2008106126A - Thermally conductive material, heat releasing substrate using this and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a circuit board or the like required with a predetermined strength is hardly used since in a heat releasing substrate using a conventional crystallized resin, the recrystallized resin itself for enhancing a thermal conductivity is hard and brittle. <P>SOLUTION: A crystalline epoxy resin 17 and a thermoplastic resin having a phenyl group 27 (or a mesogen group) such as an amorphous PPE resin 18 with a high Tg (Tg is a glass transition temperature) and high strength are mixed, and it is made to a thermal conductive insulation material in which the mutual phenyl groups 27 are oriented and crystallized and an inorganic based inorganic filler 20 is further added. Thereby, load bearing (or hardly cracking) and Tg are improved while maintaining the high thermal conductivity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat conductive material used when mounting various electronic components such as power semiconductors that require heat dissipation at high density, a heat dissipation substrate using the same, and a method of manufacturing the same.

  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 (for example, Patent Document 1) will be described with reference to FIG.

  FIG. 14 is a cross-sectional view of a conventional heat dissipation board. In FIG. 14, an electrical insulating material layer 2 is formed on the metal plate 1. And here, what added the inorganic filler to the polyimide or polyphenylene oxide as the electrical insulating material layer 2 is proposed (for example, the following patent document 1). Since polyphenylene oxide (or PPO) is a registered trademark of the General Electronic Company, in this application, polyphenylene oxide (PPO) is called polyphenylene ether (hereinafter referred to as PPE). Note that PPO and PPE are the same, and details of PPE will be described later with reference to FIG.

  A copper foil or connection foil 3 is laminated on the electrical insulating material layer 2. Then, a ceramic chip component 5, a silicon semiconductor 6, a terminal 7, and the like are mounted thereon using solder 4. Here, the electrical insulating material layer 2 has a thermal conductivity of 0.005 to 0.018 (Cal / ° C. · cm · sec) and a glass transition temperature of 164 ° C. or higher. However, a general resin such as PPE has a low thermal conductivity of the resin itself, and therefore, for electronic components that require high heat dissipation such as PDP (plasma display panel) and LED (light emitting diode) in recent years. In some cases, it was difficult to obtain a heat dissipation substrate. The conversion formula of the thermal conductivity is 1 cal / (s · m · ° C.) ≈4.2 W / (m · K).

Next, a case of increasing the heat conductivity of the resin will be described with reference to FIG. For example, it has been proposed to use a crystallized resin as means for increasing the thermal conductivity of the resin (for example, Patent Document 2 below). FIG. 15 is a schematic view of a change during a polymerization reaction of a monomer having a mesogenic group. As shown in FIGS. 15A to 15C, the monomers 9 having the 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 the crystallized resin, it is necessary to increase the crystallization rate of the crystallized resin. However, the higher the crystallization rate of the crystallization resin, the harder and more fragile the substrate will be. As a result, there is a possibility that the resin part of the obtained mounting substrate is broken and a problem that chips, cracks, etc. are likely to occur.
Japanese Patent No. 3255315 JP-A-11-323162

  As described above, the crystalline resin may be difficult to use for the heat dissipation substrate due to the physical properties unique to the crystalline resin (hard and brittle, easy to chip, and easy to break).

  The present invention solves the conventional problems, solves the problem that the crystalline resin is hard and brittle, and provides a heat conductive material that can achieve both high thermal conductivity and robustness in the heat dissipation substrate using the crystalline resin, and An object of the present invention is to provide a heat dissipation board using the same and a manufacturing method thereof.

  In order to solve the above-described conventional problems, the present invention provides a crystalline epoxy resin, a thermoplastic resin mainly composed of at least one of poniphenylene ether, polyphenylene sulfide, and polyether sulfone, and a curing agent. It constitutes a conductive material.

  And in order to compensate for the problem of hard and brittle crystalline resin, it has the same structure (for example, phenyl group) as crystalline resin, but has high glass transition temperature, high degree of polymerization, and is hard to break. Add the thermoplastic resin you have. Then, by heating and dissolving them, the thermoplastic phenyl group and the phenyl group of the crystalline resin are oriented (or crystallized) with each other in a molecular state.

  Then, the thermoplastic resin is used as a main skeleton, and the crystalline resin is positively orientated (or crystallized) around the main skeleton so as to maximize the characteristics of both.

  According to the heat conductive material of the present invention and the heat dissipation substrate using the heat conductive material and the method for manufacturing the heat dissipation substrate, the required strength (hardness to crack) is provided as a substrate for an electronic component. Further, the thermoplastic resin having the added phenyl group can improve the orientation and crystallization of the crystalline epoxy resin, and can also improve the high heat dissipation.

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

  FIG. 1 is a perspective sectional 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 thermally conductive insulating layer, which will be described later with reference to FIG. 3 and the like. At least a crystalline epoxy resin, poniphenylene ether (hereinafter referred to as PPE), polyphenylene sulfide (hereinafter referred to as PPS), polyether It is made of a heat conductive material composed of a thermoplastic resin containing at least one of sulfone (hereinafter referred to as PES) as a main component (added with an inorganic filler if necessary). 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 a heat dissipation mechanism of a heat dissipation board in which a wiring pattern is embedded. 2A and 2B, reference numeral 13 denotes an electronic component, which is a power semiconductor with heat generation, a light emitting diode (LED), a laser, 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. In FIG. 2A, the solder resist formed on the wiring pattern 10 is not shown. By forming a solder resist on the wiring pattern 10, it is possible to prevent the mounting solder (not shown) from spreading too much 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 (or heat spreads) through the wiring pattern 10 as indicated by the arrow 14b. The heat of the wiring pattern 10 is transmitted to the heat conductive insulating 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.

  Then, by cooling the electronic component 13, it is possible to increase the efficiency of the electronic component 13 (for example, increase the light amount of the light emitting diode or the semiconductor laser), increase the life, and increase the reliability. 2A and 2B, the mounting part (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 insulating layer 11 used for the heat dissipation substrate will be described.

  The manufacturing method of the heat conduction used for the heat conductive insulating layer 11 is demonstrated using FIGS. FIG. 3 is a schematic diagram illustrating an example of a method for manufacturing a heat conductive insulating material constituting the heat conductive insulating layer 11. In FIG. 3, 15 is a kneading apparatus, 17 is a crystalline epoxy resin, 18 is a PPE resin, 19 is a curing agent, and 20 is an inorganic filler. The crystalline epoxy resin 17 will be described later with reference to FIGS. 10 and 11, and the PPE resin 18 will be described with reference to FIGS.

  3 (A) to 3 (C), the kneading device 15 is a commercially available heating kneading device (for example, a planetary mixer or kneader, or a laboratory plast mill manufactured by Toyo Seiki Seisakusho Co., Ltd.). combine. The kneading mechanism 16 is a kneading mechanism portion using a motor or the like, and agitates (or kneads) the melted resins so that they become uniform at the molecular level. Further, a stirring blade of Σ type, Z type, hybrid type or the like may be attached to the tip of the kneading mechanism 16 as a stirring blade. Moreover, shapes other than a blade | wing can also be used. The kneading device 15 is one that can be heated to a predetermined temperature with a heater or the like. By heating the kneading device 15, the resin material that is in a solid state at room temperature can be dissolved (or liquefied), so that kneadability and affinity with other members can be improved.

  First, as shown in FIG. 3A, the kneading device 15 is heated to the melting point of the crystalline epoxy resin 17 or higher to be liquefied. This is because the crystalline epoxy resin 17 is in a granular state (solid state) at room temperature, and therefore, at the room temperature state, it is uniformly mixed with the PPE resin 18 or the curing agent 19 at the molecular level (particularly in the molecular state) or This is because the reaction is difficult.

  Next, as shown in FIG. 3B, a PPE resin 18 is added to the liquefied crystalline epoxy resin 17. In FIGS. 3B and 3C, the kneading mechanism 16 is not shown.

  Next, as shown in FIG. 3C, a curing agent 19 and (if necessary) an inorganic filler 20 are contained in a liquid material (or viscous material) composed of the crystalline epoxy resin 17 and the PPE resin 18. Are added gradually (or separately). At this time, it is desirable that the temperature of the liquid material (or viscous material) is higher than the lowest liquefaction temperature of these members (more than the lowest temperature at which a liquefied state can be maintained, for example, 100 ° C. or higher). These members are mixed (or kneaded) using a kneading mechanism 16 (not shown) set in the kneading device 15 at a temperature equal to or higher than the minimum liquefaction temperature, thereby homogenizing these members in a molecular state.

  When the curing agent 19 is added, the temperature of the kneading device 15 (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 insulating material is produced.

  The curing agent 19 is added after the PPE resin 18 is added. This is to delay the effect of adding the curing agent 19 to the crystalline epoxy resin 17 (for example, temperature change or curing start).

  Moreover, as the inorganic filler 20, it is desirable to use at least one inorganic filler 20 selected from alumina, aluminum nitride, boron nitride, silicon carbide, and silicon nitride. By using the inorganic filler 20 having high thermal conductivity, the thermal conductivity of the thermal conductive insulating material can be further increased. By setting the temperature of the crystalline epoxy resin 17 or the like within the range of its melting temperature (for example, 50 to 200 ° C.), the melt viscosity of the crystalline epoxy resin 17 is kept low, and the inorganic filler 20 is uniformly dispersed in the resin. Enable. Moreover, you may mix a hardening accelerator, a surface treating agent, etc.

  Next, the preforming of the heat conductive insulating material will be described. It is desirable that the heat-conducting insulating material produced as shown in FIGS. 3A to 3C is formed into a film at the same time as being taken out from the kneading device 15 (for example, the reaction kettle constituting the kneading device 15). By pre-molding the heat conductive insulating material into a film shape, the handleability of the heat conductive insulating material can be improved. Next, the preforming (for example, film formation) of the heat conductive insulating material will be described with reference to FIG.

  FIG. 4 is a cross-sectional view for explaining the preforming of the heat conductive insulating material. In FIG. 4, 21 is a heat conductive insulating material, 22 is a release sheet, and 23 is a molding apparatus. In FIG. 4, the heat conductive insulating material 21 is manufactured according to FIGS. 3A to 3C, and at least a thermoplastic resin such as PPE resin 18, a crystalline epoxy resin 17, an inorganic filler 20, and a curing agent 19. It consists of And this heat conductive insulating material 21 is set to the shaping | molding apparatus 23, it drives as shown by the arrow 14, and pre-forms in a sheet form. At this time, the release sheet 22 is sandwiched between the heat conductive insulating material 21 and the molding device 23, so that the heat conductive insulating material 21 on the surface of the processing portion of the molding device 23 (for example, a roll rotating portion or the like). Prevents dirt from being generated. The release sheet 22 is left as a kind of surface protection film on the surface of the heat conductive insulating material 21 formed into a sheet.

  As the release sheet 22, a resin film such as PET obtained by treating a commercially available surface with silicon treatment, water repellent treatment, or release treatment can be used. The thickness of the preliminarily formed heat conductive insulating material 21 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 sheet-like heat conductive insulating 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 shaping | molding apparatus 23, the moldability of the heat conductive insulating material 21 can be improved, and the thickness variation of the completed sheet-like molded product can also be reduced. And the adhesion of dust etc. is prevented by leaving the release sheet 22 as a kind of protective sheet on the surface of the heat conductive insulating material 21 preformed into a sheet shape.

  Also, coating using a coater or an extrusion molding machine can be used. You may add a solvent in order to adjust a viscosity as needed. Moreover, you may knead | mix in the state previously melt | dissolved in the solvent. The manufacturing method is not limited to this.

  Next, how a heat dissipation substrate is manufactured using the sheet-formed heat conductive insulating material 21 will be described with reference to FIGS. 5A and 5B are cross-sectional views illustrating an example of a method for manufacturing a heat dissipation board. 5A and 5B, reference numeral 24 denotes a film which prevents the surface of the molding apparatus 23 from being soiled by the heat conductive insulating material 21.

  First, as shown in FIG. 5A, a heat conductive insulating material 21 from which the release sheet 22 has been removed in advance is set between the metal plate 12 and the wiring pattern 10. The metal plate 12, the heat conductive insulating material 21, and the wiring pattern 10 are sandwiched between molding devices 23 such as a press and are heated and pressurized as indicated by an arrow 14. In FIGS. 5A and 5B, a mold and the like set in the molding apparatus 23 are not shown. Then, as shown by the arrow 14 in the molding apparatus 23, these members are pressed at a predetermined temperature and integrated.

  Thereafter, the molding device 23 is pulled away in the direction of the arrow 14 as shown in FIG. Thereafter, the film 24 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 a part or more of the wiring pattern 10 in the heat conductive insulating layer 11 in this manner, 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, the thickness of the wiring pattern 10 protruding from the surface of the heat conductive insulating layer 11 is reduced.

  Here, as the wiring pattern 10, for example, a lead frame having a thickness of 0.3 mm can be used. Then, by embedding a part or more of the lead frame in the heat conductive insulating layer 11, the protruding amount (or step) of the wiring pattern 10 from the heat conductive insulating layer 11 is 50 μm or less (desirably 20 μm or less, further 10 μm). 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.

  Furthermore, by embedding a part or more of the wiring pattern 10 in the heat conductive insulating layer 11, in addition to increasing the connection strength between the wiring pattern 10 and the heat conductive insulating layer 11, the tensile strength of the wiring pattern 10 can also be increased (tensile Regarding the strength measurement method, the tensile strength evaluation method of the copper foil on the printed wiring board can be referred to).

  Next, the PPE resin 18 and the crystalline epoxy resin 17 which are members constituting the heat conductive insulating material 21 will be described individually.

  First, the PPE resin 18 will be described with reference to FIGS. FIG. 6 is a structural diagram showing an example of a method for producing a PPE resin. In general, the PPE resin 18 may be one using an organic solvent, but one synthesized using supercritical carbon dioxide or the like can also be used. For example, in FIG. 6, 25 is DMP and 26 is DPQ. DMP 25 is 2,6 dimethyl phthalate and is a starting material for the PPE resin 18. This is polymerized by a coupling reaction using a catalyst such as Cu to obtain PPE resin 18. In this reaction, DPQ26 is produced as a by-product. DPQ is diphenoquinone. By optimizing the base concentration, temperature, stirring method, and the like during this reaction, DPQ26 by-product can be suppressed and higher molecular weight PPE (preferably n is 100 or higher, or molecular weight is 30,000 or higher) can be synthesized. Here, the degree of polymerization (n) of the PPE resin 18 is desirably 100 or more. When the degree of polymerization of the PPE resin 18 is less than 100, physical strength as a wiring board may not be obtained.

  7A and 7B are a structural formula and a schematic diagram of a PPE resin. In FIGS. 7A and 7B, 27 is a phenyl group. FIG. 7A shows a structural formula of PPE resin. FIG. 7B is a schematic diagram for explaining the main chain (or phenyl group 27) portion of the PPE resin 18 in an amorphous state. As shown in FIG. 7A, the PPE resin 18 is bonded with oxygen (O) via a phenyl group 27 (in FIG. 7B, the phenyl group 27 is indicated by a square) continuously in a flexible state. ing. Here, since the PPE resin 18 itself is an essentially amorphous thermoplastic resin, its thermal conductivity is low.

  Such a PPE resin 18 regularly has a large number (for example, n ≧ 100) of phenyl groups 27 in the main chain. In the present embodiment, attention is paid to the regularly arranged phenyl groups 27, and the crystalline epoxy resin 17 having a small number (for example, 2 to 20) of phenyl groups 27 as described later with reference to FIG. In addition, the phenyl groups 27 of the PPE resin 18 are aligned with each other and crystallized to increase the thermal conductivity. In general, as a method for improving Tg, there is a case where a curing agent 19 that easily takes a network structure is blended, but crystallization is inhibited and high thermal conductivity cannot be obtained. Therefore, it is positive that the phenyl group 27 of the PPE resin 18 (or a mesogen group portion that is thought to contribute to crystallization) and the phenyl group 27 (or mesogen group portion) of the crystalline epoxy resin 17 are common elements. These are used and oriented (or crystallized). Thereby, the crystallinity degree of crystalline epoxy resin itself can also be improved.

  As the PPE resin 18, a modified PPE resin may be selected. As the modified polyphenylene ether (m-PPE), an aromatic polyether resin PPE having an ether group (COC) as a main component and modified with a polymer alloy with a styrene resin (for example, polystyrene) can be used. . By carrying out such modification to obtain a modified PPE resin, it is possible to increase the strength and increase the Tg by having a crosslinking point with the crystalline epoxy resin 17.

  Next, the crystalline epoxy resin 17 that promotes crystallization by causing a phenyl group portion forming the main chain of the PPE resin 18 and a kind of orientation phenomenon will be described with reference to FIG.

FIGS. 8A and 8B and FIGS. 9A to 9F are structural formulas showing examples of crystalline epoxy resins. In FIG. 8A, X in the structural formula of the crystalline epoxy resin 17 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.

  FIG. 8B is a structural diagram of a curing agent used for curing the crystalline epoxy resin 17. In the structural formula of FIG. 8B, X is S (sulfur) O (oxygen) or a short bond. A material obtained by mixing and polymerizing the main agent of FIG. 8A and the curing agent 19 of FIG. 8B may be called a crystalline epoxy resin.

  The ratio of the main agent and the curing agent 12 is calculated from the epoxy equivalent. Further, a curing agent 12 other than that shown in FIG. 8B may be used as the curing agent 12. As the crystalline epoxy resin 17, those shown in FIGS. 9A to 9F can also be used.

  FIGS. 9A to 9F are structural diagrams showing an example of a crystalline epoxy resin that easily crystallizes with a PPE resin. Such a crystalline epoxy resin 17 has a melting point of about 50 to 121 ° C. and a lower dissolution viscosity (for example, a viscosity at 150 ° C. of 6 to 20 mPa · s). In this step, the effect of easily mixing and dispersing the PPE resin 18 and the inorganic filler 20 is obtained. The degree of polymerization of the crystalline epoxy resin 17 is suitably 20 or less (further 10 or less, desirably 5 or less). This is because when the degree of polymerization is greater than 20, the molecules become too large to be crystallized in a state of being oriented in the PPE resin 18.

  Next, the crystallization mechanism of the PPE resin 18, the crystalline epoxy resin 17, and the curing agent 19 will be described with reference to FIG. FIG. 10 is a schematic diagram for explaining how the PPE resin, the crystalline epoxy resin, and the curing agent crystallize each other, and 28 is a dotted line. In FIG. 10, in the PPE resin 18, a plurality of phenyl groups 27 are polymerized in a chain via oxygen (indicated as O in FIG. 10). The PPE resin 18 is used as a main skeleton, and the phenyl group 27 of the crystalline epoxy resin 17 is oriented and crystallized on the phenyl group 27 of the PPE resin. In FIG. 10, the phenyl group 27 of the PPE resin 18 is shown as a rectangle, which means that the phenyl group 27 is a kind of plate-like structure. In this embodiment, the crystalline epoxy resin 17 having the same phenyl group 27 is crystallized by utilizing the fact that the phenyl group 27 has a plate-like structure and has a certain direction. In FIG. 10, a dotted line 28 indicates a portion where the phenyl group 27 of the PPE resin 18 and the phenyl group 27 of the crystalline epoxy resin 17 are oriented and crystallized.

  Next, how to distinguish whether or not the phenyl groups 27 are crystallized between the PPE resin 18 and the crystalline epoxy resin 17 and the curing agent 19 will be described with reference to FIG.

  FIG. 11 is a diagram showing a thermal analysis result. 11A and 11B, the X axis is temperature (° C.) and the Y axis is thermal expansion coefficient (relative value). Reference numerals 31a and 31b are graphs corresponding to respective measurement results.

  FIG. 11A shows a thermal mechanical analysis TMA (Thermo mechanical Analysis) of a reaction product of the crystallized epoxy resin 17 and the curing agent 19. The reaction product of the crystallized epoxy resin 17 and the curing agent 19 (shown by the graph 31a) has two inflection points, Tg1 and Tg2. This is a phenomenon that occurs because 100% of the crystallized epoxy resin 17 is not crystallized. Here, Tg1 is Tg of a reaction product that is not crystallized, and Tg2 is considered to be Tg of the crystallized portion (temperature at which crystallinity collapses). It is the resin part that is crystallized that provides high thermal conductivity. In general, Tg1 is often used as the Tg of the reaction product, but compared with normal Tg, the amount of change in the thermal expansion coefficient and the elastic behavior are relatively maintained up to Tg2, but the heat-resistant temperature as the substrate Is determined by Tg1. Therefore, as described in the embodiment of the present invention, in order to obtain a high thermal conductivity, the PPE resin 18 and the crystalline epoxy resin 17 are heated as described with reference to FIGS. Thus, the PPE resin 18 as the main chain and the phenyl groups 27 of the crystalline epoxy resin 17 are easily matched. Thus, by making it easy for the phenyl groups 27 to overlap each other in the molecular state, the thermal conductivity of the resin portion having the phenyl groups 27 after curing (and after cooling) can be increased.

  As a result, the TMA of the reaction product of PPE resin 18, crystalline epoxy resin 17 and curing agent 19 (illustrated by graph 31b) has a small inflection of Tg1 as shown in FIG. improves.

  Here, as a method for improving Tg, there is a method of blending a curing agent that easily takes a network structure. However, in the case of the crystalline epoxy resin 17, crystallization is hindered by blending a structurally different resin, and high heat In many cases, conductivity cannot be obtained.

  The present invention solves the conventional problems, solves the problem that the crystalline resin is hard and brittle, and the Tg of the non-crystalline portion is low, and the heat dissipation substrate using the crystalline resin has high thermal conductivity and durability. The present invention provides a thermally conductive material that can balance the thickness, a heat dissipation substrate using the same, and a manufacturing method thereof.

  Further, when the PPE resin 18 is modified to give a thermosetting property having an epoxy group, it has a network structure crosslinking point with the crystallized epoxy resin 17 and Tg is increased.

  Here, in the case of a thermally conductive material composed of a thermoplastic resin such as the PPE resin 18, the crystalline epoxy resin 17, the curing agent 19 and an inorganic filler, the molecular weight of the thermoplastic resin is increased (or the degree of polymerization is increased). Is desirable. By increasing the molecular weight of the thermoplastic resin (or increasing the degree of polymerization), the physical strength of the resulting thermally conductive material can be increased. Therefore, the degree of polymerization of the thermoplastic resin is desirably 100 or more.

  On the other hand, according to experiments by the inventors, in the case of a thermally conductive material composed of the crystalline epoxy resin 17 and the curing agent 19, a thermoplastic resin such as PPE, and the inorganic filler 20, the crystalline epoxy resin 17 As a result of experiments with varying degrees of polymerization, it was found that the higher the degree of polymerization of the crystalline epoxy resin 17, the lower the thermal conductivity. Therefore, the crystallization of the crystalline epoxy resin 17 was investigated by various methods with the cooperation of the in-house analytical department. As the degree of polymerization of the crystalline epoxy resin 17 increased, the crystallized state in the mixed state with the thermoplastic resin increased. It was found that the crystallization of the conductive epoxy 17 is inhibited. That is, as the degree of polymerization of the crystalline epoxy resin 17 is increased, the crystallization of the crystalline epoxy resin 17 in the completed thermally conductive material is inhibited (particularly, the crystallization of the crystallized epoxy resin 17 adjacent to the PPE). Was found to be hindered). It has been found that the crystallization of the crystallized epoxy resin 17 is hindered, that is, the free long chain portion that does not contribute to the crystallized structure is difficult to take or does not contribute to the crystallized structure inside the thermally conductive material. It has been found that the thermal conductivity decreases as the number of free long chain portions that do not contribute to the crystallized structure of the crystallized epoxy resin 17 increases. Further, as a result of the increase of such free long chain portions, it was found that the Tg (glass transition temperature) of the resulting heat conductive material is affected (the proportion of Tg of the resin portion not crystallized increases). Oops). Thus, when the polymerization degree of the crystallized epoxy resin 17 was too high, it turned out that the subject that the heat conductivity of heat conductive material itself falls and Tg falls generate | occur | produces. In the experiments conducted by the inventors, good results were obtained when the degree of polymerization of the crystalline epoxy resin 17 was 20 or less (more preferably 10 or less, more preferably 5 or less).

  Next, the ratio between the PPE resin 18 and the crystalline epoxy resin 17 will be described. The PPE resin 18 is desirably within a range of 3 to 20 wt% (crystallized epoxy resin + curing agent is 85 to 97 wt%) with respect to the total resin. When the proportion of the PPE resin 18 is less than 3 wt%, the completed heat conductive insulating layer 11 may become brittle. Further, when the proportion of the PPE resin 18 exceeds 20 wt%, the proportion of the crystallized epoxy resin is lowered, so that the thermal conductivity of the completed thermally conductive insulating layer 11 may be affected.

  In addition, in the ratio of the inorganic filler 20 and the total resin (here, the total resin means the total of the PPE resin 18 and the crystalline epoxy resin 17 + curing agent 19 and corresponds to the resin binder), the inorganic filler 20 has a ratio of 50. It is desirable to be in the range of -95 Vol% (resin binder is 50-5 Vol%). When the ratio of the inorganic filler 20 is less than 50 Vol%, the thermal conductivity of the thermally conductive insulating layer 11 formed by curing the thermally conductive insulating material 21 may be reduced. Moreover, when the ratio of the inorganic filler 20 becomes larger than 95 Vol%, the moldability of the heat conductive insulating material 21 may be affected. Here, wt% means weight%, and Vol% means volume%.

  The average particle size of the inorganic filler 20 is desirably in the range of 1 μm to 100 μm. When the average particle size is 1 μm or less, the specific surface area becomes large, the kneading of the heat conductive insulating material 21 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 20, a plurality of types of inorganic fillers 20 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)
"YL6121H" manufactured by Japan Epoxy Resin as "Crystalline Epoxy Resin 17", "YSLV-80XY" manufactured by Tohto Chemical Co., Ltd., 4-4 diaminobiphenyl ether, 4-4, dihydroxybiphenyl as curing agent 19, and PPE powder as thermoplastic resin Prepared.

  The crystalline epoxy resin 17 was melted by heating, and the curing agent 19 and PPE (1 to 30 Wt%) were mixed and stirred. A sample not mixed with PPE is also prepared as a sample for comparison and measurement. Moreover, the sample using 4-4, dihydroxy biphenyl has added imidazole 0.5Wt% as a hardening accelerator.

  This mixture was formed into a sheet having a thickness of 500 μm. After molding, the film was laminated in a shape according to the measurement, and then cured under conditions of 180 ° C. × 2 Hour, and various measurements were performed.

Measurement of thermal conductivity: Bruker AXS Xenon laser flash Sample size: φ1 / 2 inch, t1mm
TMA compression load measurement: Seiko's sample size: 4mm x 4mm x t3mm
Breaking strength test: see FIG. 12 FIG. 12 shows an example of a bending strength evaluation method. In FIG. 12, 29 is a sample and 30 is a jig. In FIG. 12, the sample 29 is set between the jigs 30, and the sample 29 is bent using the jigs 30 in the direction indicated by the arrow 14. In the experiments of the inventors, the sample 29 was broken (broken) at the time when the conventional product was bent by 1 to 2 mm. On the other hand, Sample 29 of the present invention did not break even when bent by 4 to 5 mm. The sample size (sample shape) is 40 mm × 4 mm × t2 mm.

  The measurement results of YL6121 and 4-4 diaminobiphenyl are shown in (Table 1).

  By adding PPE, an improvement in thermal conductivity (= an improvement in crystallization rate) was observed in samples of 20% or less. In the breaking strength test, Samples 1 and 2 fractured at the values shown in (Table 1), but Samples 3 to 7 were largely bent and did not break within the range of the measuring instrument used this time.

    Next, TMA measurement results of YSLV-80XY and dihydroxybiphenyl are shown in FIGS. 13 (A) to (C). FIG. 13A shows a PPE blending amount of 0% (shown by graph 31a), and FIG. 13B shows a blending amount of 10% (shown by graph 31b). FIG. 13C is a composite diagram (combination of graph 31a and graph 31b). As shown in FIG. 13C, the degree of inflection of Tg1 is different, and the crystallinity is improved and Tg1 is hardly understood by the blending of PPE.

  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.

1 is a partially cutaway perspective view of a heat dissipation board in an embodiment of the present invention. (A) (B) is sectional drawing explaining the heat dissipation mechanism of the thermal radiation board | substrate which embedded the wiring pattern. (A)-(C) are schematic diagrams which show an example of the manufacturing method of heat conductive resin. Sectional drawing explaining pre-formation of heat conductive insulating material (A) (B) is sectional drawing explaining an example of the manufacturing method of a thermal radiation board | substrate. Structural diagram showing an example of PPE resin manufacturing method (A) and (B) are diagrams and schematic views showing the structural formula of PPE resin. (A) (B) is a figure which shows structural formula which shows an example of a crystalline epoxy resin. (A)-(F) is a figure which shows structural formula which shows an example of a crystalline epoxy resin together Schematic diagram explaining how PPE resin and crystalline epoxy resin crystallize each other (A) and (B) are TMA characteristic model diagrams Breaking strength test model diagram (A)-(C) are figures which show a TMA measurement result. Sectional view of a conventional heat dissipation board using PPE (A)-(C) are schematic diagrams of changes during the polymerization reaction of a monomer having a mesogenic group

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wiring pattern 11 Thermal conductive insulating layer 12 Metal plate 13 Electronic component 14 Arrow 15 Kneading apparatus 16 Kneading mechanism 17 Crystalline epoxy resin 18 PPE resin 19 Hardener 20 Inorganic filler 21 Thermal conductive insulating material 22 Release sheet 23 Molding apparatus 24 Film 25 DMP
26 DPQ
27 Phenyl group 28 Dotted line 29 Sample 30 Jig 31a, 31b Graph

Claims (9)

A thermoplastic resin mainly composed of at least one of poniphenylene ether, polyphenylene sulfide, and polyether sulfone;
Crystalline epoxy resin,
A thermally conductive material consisting of a curing agent. A thermoplastic resin mainly composed of at least one of poniphenylene ether, polyphenylene sulfide, and polyether sulfone;
Crystalline epoxy resin,
A curing agent;
Thermally conductive material composed of inorganic filler. The thermally conductive material according to claim 1 or 2, wherein the crystalline epoxy resin has the following structural formula.


X: C, O, S or short bond
R1, R2, R3, R4: CH3, H, t-Bu (R1 to R4 may be the same) The thermally conductive material according to claim 1 or 2, wherein the thermoplastic resin contains polyphenylene ether, and the polyphenylene ether contains a modified polyphenylene ether. The heat conductive material according to claim 1 or 2, wherein the degree of polymerization of the crystalline epoxy resin is 20 or less. The thermally conductive material according to claim 1 or 2, wherein the degree of polymerization of the thermoplastic resin is 100 or more. The heat conductive material according to claim 2, wherein the inorganic filler is an inorganic filler composed of at least one selected from alumina, aluminum nitride, boron nitride, silicon carbide, and silicon nitride. A heat conductive insulating layer, a metal plate bonded to the heat conductive insulating layer, and a wiring pattern in which at least a part is embedded in the heat conductive insulating layer,
The thermally conductive insulating layer includes a crystalline epoxy resin,
A resin mainly composed of at least one of poniphenylene ether, polyphenylene sulfide, and polyether sulfone;
A curing agent;
A heat dissipation substrate made of an inorganic filler. At least on a metal plate,
At least a crystalline epoxy resin preformed into a sheet,
A thermoplastic resin mainly composed of at least one of poniphenylene ether, polyphenylene sulfide, and polyether sulfone;
A curing agent;
A thermally conductive material comprising an inorganic 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.