JP2009021469A - Heat conductive printed wiring board, laminated composite sheet used therefor and method of manufacturing the same, and method of manufacturing heat conductive printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board which hardly cracks even when its heat conductivity is increased. <P>SOLUTION: A printed wiring board 24 which is formed by impregnating glass fiber 13 with epoxy resin and satisfies standards of FR4 and FR5 is used for a core part (or a center part), and a laminated composite layer comprising a first composite layer 15 and a second composite layer 16, and a surface layer wiring pattern 17 are formed on one or more surfaces thereof to obtain the heat conductive printed wiring board 11 which has high heat conductivity and hardly cracks. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat transfer printed wiring board used for mounting various electronic components such as power semiconductors and high-performance semiconductors that require heat dissipation at high density, a heat transfer prepreg used therefor, and a method for manufacturing the same. It is about.

  2. Description of the Related Art Conventionally, printed wiring boards for mounting electronic components have been obtained by laminating, integrating, and curing a plurality of prepregs made of glass epoxy resin and copper foil. Furthermore, with the miniaturization and high performance of equipment, heat generation of electronic components often becomes a problem, and a printed wiring board having heat dissipation (or heat transfer) is required. Next, the heat transfer printed wiring board will be described.

  For example, using a crystalline epoxy resin with improved thermal conductivity, a material with improved thermal conductivity has been proposed. An example will be described with reference to FIG. That is, FIGS. 9A and 9B are cross-sectional views illustrating a state in which a crystalline polymer having both mesogenic groups is oriented using a magnetic field to increase the thermal conductivity (see, for example, Patent Document 1). ).

  9A and 9B, magnetic force lines indicated by arrows 2 are generated between a plurality of magnets 1 (for example, permanent magnets as magnetic field generating means). Then, a resin 4 (for example, a crystalline epoxy resin in a liquid state before being cured) placed in the mold 3 is placed between the magnetic field lines indicated by the arrows 2, and the resin 4 is thermally cured in this magnetic field. . 9A shows a state in which a magnetic field is applied in a direction perpendicular to the resin 4, and FIG. 9B shows a state in which a magnetic field in a parallel direction is applied.

  However, in order to orient the crystalline epoxy which is originally hard to be magnetized, it is cured for 10 minutes to 1 hour in the mold 3 heated to a temperature of 150 to 170 ° C. in a high magnetic field with a magnetic flux density of 5 to 10 terraces. Special processing is required. The crystalline epoxy resin thus formed may have anisotropy in thermal conductivity and physical strength (for example, bending strength). As a result, the prepreg and printed wiring board produced using such a crystalline epoxy resin have direction dependency (or anisotropy), and thus flexibility is reduced (for example, bending resistance is reduced, Or, it is easy to break when bent.

  On the other hand, in order to increase the thermal conductivity of the prepreg, it has been proposed to add an inorganic filler at a high density. However, a sheet-like prepreg to which an inorganic filler is added at a high density is hard and difficult to bend, and may be broken only by being wound. Moreover, in order to increase the quantity of the inorganic filler with respect to the glass fiber with low heat conductivity, it is necessary to make a glass woven fabric thin, and an intensity | strength falls.

  And the printed wiring board itself obtained by laminating and curing the prepreg which is hard and difficult to bend easily breaks when bent. Therefore, a problem may occur when electronic components are mechanically mounted on such a printed wiring board or when the printed wiring board is mounted on a device after mounting.

  In response to these problems, proposals have been made to improve both thermal conductivity and handleability (for example, workability of prepreg sheets and bending resistance).

  FIG. 10 is a cross-sectional view showing an example of a conventional heat transfer prepreg with improved bendability, which is proposed in Patent Document 2, for example. In FIG. 10, a conventional heat transfer prepreg 5 includes glass fibers 6, a thermosetting resin layer (inner layer portion) 7, and an inorganic filler-added thermosetting resin layer (outer layer portion) 8. Here, the inorganic substance is added to increase the thermal conductivity of the inorganic filler-added thermosetting resin layer 8 constituting the outer layer portion. And as shown in FIG. 10, the inorganic filler addition thermosetting resin layer 8 comprises the outer layer part of the conventional heat-transfer prepreg 5, and the part (what is called inner layer part) which covers the glass fiber 6 is an inorganic filler. The thermosetting resin layer 7 is not included. Due to the presence of the glass fiber 6 layer that is not impregnated with the inorganic filler, the rigidity of the glass fiber 6 does not increase (or the flexibility of the glass fiber 6 is maintained), and the sheet-like conventional heat transfer prepreg 5 is provided. This improves the bendability (or flexibility).

However, in the configuration shown in FIG. 10, the thermal conductivity in the thickness direction of the conventional prepreg 5 may be hindered. This is because the thermal conductivity of the glass fiber 6 and the thermosetting resin layer 7 is lower than that of the inorganic filler-added thermosetting resin layer 8 in the outer layer portion.
JP 2004-225054 A Japanese Patent Laid-Open No. 3-17134

  As described above, in the case of the conventional printed wiring board, when trying to increase the thermal conductivity of the printed wiring board, the flexibility that it is easy to break when bent, the fluidity necessary for wiring embedding tends to decrease, the flexibility and When trying to increase the fluidity, there is a problem that it is difficult to increase the thermal conductivity. Conventionally, thermal conductivity in the thickness direction of the printed wiring board has been a problem, and it has been necessary to improve the thermal conductivity of the entire printed wiring board.

  Accordingly, the present invention provides a heat transfer printed wiring board capable of maintaining its flexibility and fluidity while increasing the thermal conductivity in the planar direction of the printed wiring board, a heat transfer prepreg used therefor, and a method for manufacturing the same. Objective.

  In order to achieve this object, the present invention provides a printed wiring board, a laminated composite layer having a thermal conductivity of 3 W / (m · K) or more and 20 W / (m · K) or less formed on one or more surfaces thereof, The heat transfer printed wiring board is composed of a surface wiring pattern formed on the laminated composite layer.

  According to the heat transfer printed wiring board of the present invention, the heat transfer prepreg used in the heat transfer printed wiring board, and the manufacturing method thereof, the central portion (sometimes referred to as the core portion) of the heat transfer printed wiring board includes the conventional FR4 and FR5. Since a highly reliable printed wiring board called a built-in is built in, the reliability and mechanical strength of the heat transfer printed wiring board can be increased.

  In the heat transfer printed wiring board of the present invention, a laminated composite layer having a thermal conductivity of 3 W / (m · K) or more and 20 W / (m · K) or less is formed on one surface or more of the printed wiring board serving as a core portion. Thus, the heat generated in the electronic component mounted on the laminated composite layer is diffused in the plane direction through the laminated composite layer. Alternatively, heat can be radiated to the thick copper foil formed on the printed wiring board of FR4 or FR5 in the core portion through the surface layer wiring pattern or blind via formed in the laminated composite layer.

  As a result, the temperature of the semiconductor or the like mounted on the heat transfer printed wiring board is reduced, and heat countermeasures are facilitated. In addition, electronic components and the like can be mounted with high density, and liquid crystal televisions, plasma televisions, and various electronic devices can be downsized and improved in performance.

  Further, if necessary, by forming a thick copper foil on the surface layer of the printed wiring serving as the core portion, a heat dissipation effect (referred to as a heat spread effect) via the thick copper foil can be utilized.

  Further, unevenness on the surface of the heat transfer printed wiring board, which is likely to occur due to the thickness of the thick copper foil, can be dealt with by multilayering the heat transfer prepreg.

(Embodiment 1)
Hereinafter, the heat transfer prepreg according to Embodiment 1 of the present invention will be described.

  1 is a cross-sectional view of a heat transfer printed wiring board according to Embodiment 1. FIG. In FIG. 1, 11 is a heat transfer printed wiring board, 12 is an epoxy resin layer, 13 is glass fiber, 14 is a thick copper foil, 15 is a first composite layer, 16 is a second composite layer, and 17 is a surface wiring pattern. , 18 are blind vias.

  First, a description will be given with reference to FIG. As shown in FIG. 1, the heat transfer printed wiring board 11 described in the first embodiment is provided with an epoxy resin layer 12 impregnated with glass fibers 13 at the center thereof.

  Then, a thick copper foil 14 is formed on one surface or more of the epoxy resin layer 12. Then, the first composite layer 15 is formed so as to absorb the thickness of the thick copper foil 14. Thus, by making the thickness of the first composite layer 15 thicker than the thickness of the thick copper foil 14, the thickness of the thick copper foil 14 is absorbed by the first composite layer 15.

  Then, a part of the surface layer wiring pattern 17 formed on the surface of the second composite layer 16 is used as a blind via 18 to connect the surface layer wiring pattern 17 and the thick copper foil 14.

  Next, the heat transfer mechanism of the heat transfer prepreg will be described with reference to FIG. FIG. 2 is a cross-sectional view illustrating the heat transfer mechanism of the heat transfer prepreg. In FIG. 2, 19 is an electronic component in which heat generation such as a power semiconductor is an issue, 20 is a solder portion, and corresponds to a portion where the electronic component 19 is mounted on the surface layer wiring pattern 17. Bump mounting, wire mounting, or the like may be used. Reference numeral 21 denotes an arrow. In FIG. 2, the arrow 21 indicates how heat is diffused.

  In FIG. 2, the heat generated in the electronic component 19 spreads to the thick copper foil 14 and the composite layers 15 and 16 through the solder portion 20 as indicated by an arrow 21 and is diffused and radiated.

  Here, the thick copper foil 14 can be used as an electrode for heat dissipation (or heat spread) by using a material having high thermal conductivity such as copper as the thick copper foil 14. Moreover, the contact area with the 1st composite layer 15 in the side part of the thick copper foil 14 may be increased by increasing the thickness of the thick copper foil 14 or by tapering the side face of the thick copper foil 14. The heat radiation effect from the thick copper foil 14 to the composite layers 15 and 16 can be enhanced.

  Further, by using a thick material (for example, 30 microns or more and 120 microns or less) as the thick copper foil 14, the heat dissipation property (or heat spread property) can be further enhanced. Moreover, since the wiring resistance of the thick copper foil 14 can be suppressed, it can cope with a large current of 3 amperes or more.

(Embodiment 2)
In the second embodiment, an example of a method for manufacturing the heat transfer printed wiring board 11 described in the first embodiment will be described.

  3-7 is sectional drawing explaining an example of the manufacturing method of the heat-transfer printed wiring board 11. FIG.

  FIG. 3 is a cross-sectional view illustrating a state in which a laminated composite material is laminated on the surface of a printed wiring board. In FIG. 3, 23 is a laminated composite sheet, and 24 is a printed wiring board.

  First, as shown in FIG. 3, a printed wiring board 24 is set at the center. As the printed wiring board 24, one made of glass epoxy resin in which the glass fiber 13 is impregnated in the epoxy resin layer 12 can be selected. Further, as the printed wiring board 24, heat transfer printing is performed by using a highly reliable material such as FR4 or FR5 (FR4 and FR5 are American National Standards Institute, commonly known as American printed wiring board standards called ANSI). The reliability of the wiring board 11 can be improved.

  In addition, as the electrode formed on the outermost layer of the printed wiring board 24, the heat transfer property of the heat transfer printed wiring board 11 can be improved by using a thick copper foil 14 having a large thickness (for example, 30 microns or more and 120 microns or less). .

  In FIG. 3, a laminated composite sheet 23 is obtained by laminating composite layers 15 and 16 on the surface of a film 22 such as a PET film.

  Next, as shown by an arrow 21 in FIG. 3, the laminated composite sheet 23 is set on one surface or more of the printed wiring board 24, and these members are attached using a pressing device or a mold (both not shown). Pressurize and heat to integrate.

  FIG. 4 is a cross-sectional view for explaining a state in which the laminated composite sheet is fixed to one or more surfaces of the printed wiring board 24. As indicated by an arrow 21 in FIG. 4, these members are pressurized and heated using a press device, a mold, a heater, or the like (these are not shown).

  At this time, the thickness of the first composite layer 15 is desirably thicker than the thick copper foil 14 formed on the surface layer of the printed wiring board 24 (desirably 5 microns or more and 100 microns or less). This is because the thickness of the thick copper foil 14 is absorbed by the first composite layer 15. When these wall thickness differences are less than 5 microns, irregularities due to the thick copper foil 14 may appear on the surface of the heat transfer printed wiring board 11. If the thickness difference exceeds 100 microns, the heat transfer property of the heat transfer printed wiring board 11 and the workability of the blind via 18 may be affected.

  Note that both the first composite layer 15 and the second composite layer 16 are preferably composed of at least a resin and an inorganic filler. The reason why the inorganic filler is added is to increase the heat conductivity of the composite layers 15 and 16.

  Further, the content of the inorganic filler in the second composite layer 16 is preferably 60% by volume or more and 95% by volume or less. If the amount is less than 60% by volume, the heat conductivity in the second composite layer 16 may be lowered. If it exceeds 95% by volume, the moldability as the second composite layer 16 may be affected.

  Further, the content of the inorganic filler in the first composite layer 15 is preferably 0% by volume or more and 50% by volume or less (desirably 40% by volume or less). When the content of the inorganic filler in the first composite layer 15 exceeds 50% by volume, the fluidity at the time of pressurization and heating may decrease, and in the laminating process shown in FIGS. The unevenness of the copper foil 14 may not be absorbed.

  The resin constituting the composite layers 15 and 16 may be a thermoplastic resin or a thermosetting resin. The resin material constituting the first composite layer 15 is desirably lower in the softening temperature in the range of 10 ° C. or more and 200 ° C. or less than the amount of the resin material constituting the second composite layer. This is because the first composite layer 15 absorbs the thickness of the thick copper foil 14 formed on the surface layer of the printed wiring board 24. When the difference in softening temperature is less than 10 ° C., the second composite layer is deformed together with the first composite layer 15, and irregularities due to the thick copper foil 14 are generated on the surface of the completed heat transfer printed wiring board 11. There is a case. Moreover, when the temperature difference of softening temperature exceeds 200 degreeC, the preservability of the laminated composite sheet 23 and the handleability may be affected.

  In the case of a thermoplastic resin, the softening temperature may be the glass transition temperature as the softening temperature, but may also be penetration measurement using TMA. TMA means thermomechanical analysis.

  In addition, the softening temperature in a thermosetting resin can be made into the softening temperature in the semi-hardened state (state called B stage) before this hardening.

  In addition, JIS K7234 (the softening point test method of an epoxy resin) can be used for the softening temperature in a thermosetting resin (for example, epoxy resin).

  Or it is good also considering the softening temperature difference of resin which comprises the composite layers 15 and 16 as a load deflection temperature difference. Here, the deflection temperature under load is defined by JIS K 7191 or the like, in which the oil temperature is raised at a constant temperature (120 ° C./hour) and the deflection amount of the sample is measured.

Or it is good also considering the softening temperature difference of resin which comprises the composite layers 15 and 16 as a Vicat softening temperature difference. Here, the Vicat softening temperature is defined by JIS K7206, etc., and the oil temperature is raised to a constant temperature (50 ° C./hour) in the oil, and a needle with a cross-sectional area of 1 mm ² is pressed against the sample. It is something to be evaluated.

  FIG. 5 is a cross-sectional view illustrating a state after the printed wiring board 24 and the laminated composite sheet 23 are integrated. After these are integrated, the film 22 is removed as shown by the arrow 21 in FIG. Here, the film 22 is for holding the composite layers 15 and 16, but the composite layers 15 and 16 are soiled on the surface of the mold (not shown) during pressing by performing as shown in FIG. To prevent adhesion.

  FIG. 6 is a cross-sectional view for explaining how holes are formed in the composite layers 15 and 16. In FIG. 6, reference numeral 25 denotes a hole, which is formed, for example, by irradiating a predetermined position on the composite layers 15 and 16 with a laser (a laser device or the like is not shown) as indicated by an arrow 21.

  As shown in FIG. 6, since the thickness of the composite layers 15 and 16 covering the thick copper foil 14 is smaller than that of the other portions, the holes 25 can be formed with less laser power. As a result, it is difficult for the laser to cause damage such as oxidation or alteration on the surface of the thick copper foil 14.

  The via need not be limited to the blind via 18. For example, a drill that rotates at high speed may be used instead of the laser. For example, in FIG. 6, a through hole may be formed using a drill in the direction of arrow 21, and copper plating or the like may be performed on the inner wall of the through hole to form an interlayer connection via (or thermal via). The printed wiring board 24 shown in FIGS. 1 to 7 may be a multilayer printed wiring board instead of the double-sided printed wiring board. By using the printed wiring board 24 as a multilayer printed wiring board, the electronic device can be downsized. When the multilayer printed wiring board is used as the printed wiring board 24, the reliability of the completed heat transfer printed wiring board 11 can be improved by selecting one that satisfies the FR4 and FR5 standards. Further, by selecting the thickness and bending strength of the printed wiring board 24, the bending strength and the like of the completed heat transfer printed wiring board 11 can be increased. Note that it is possible to reduce the cost by selecting a commercially available printed wiring board 24.

  The thickness of the thick copper foil 14 formed on the surface of the printed wiring board 24 is preferably 30 microns or more and 120 microns or less. If it is less than 30 microns, the heat dissipation effect via the thick copper foil 14 may be affected. Moreover, when it exceeds 120 microns, the processing accuracy of the thick copper foil 14 may decrease.

  FIG. 7 is a cross-sectional view for explaining how the surface layer wiring pattern 17 is formed on the surfaces of the composite layers 15 and 16. The surface layer wiring pattern 17 can be formed by a thin film method (sputter deposition), plating (electroless, electrolysis) or the like. Note that it is desirable to select copper as the metal material constituting the surface layer wiring pattern 17. This is because copper has low electrical resistance, high thermal conductivity, and can be soldered. The thickness of the surface layer wiring pattern 17 is preferably 5 microns or more and 150 microns or less. If it is 5 microns or less, it may affect the wiring resistance and heat conductivity. Moreover, when it exceeds 150 microns, the use may be limited.

  After the state of FIG. 7, an etching process (removal of unnecessary surface layer wiring pattern 17 after forming a resist pattern, which is omitted here) is performed as heat transfer printed wiring board 11 of FIG. 1. Complete. In FIG. 1 and FIG. 2, the solder resist and the like are not shown.

(Embodiment 3)
In the third embodiment, an example of a method for manufacturing the laminated composite sheet 23 will be described.

  As shown in FIG. 3, the laminated composite sheet 23 is desirably formed on the film 22 in the order of the second composite layer 16 and the first composite layer 15. This is because the first composite layer 15 formed on the surface layer is positively deformed to absorb the thickness of the thick copper foil 14. The composite sheet 23 may have two or more layers. Further, by performing a peeling treatment or the like on the surface of the film 22, workability of the peeling process of the film 22 shown in FIG. 5 can be improved.

  Next, a method for manufacturing the laminated composite sheet 23 will be described. First, the resin and the inorganic filler constituting the composite layers 15 and 16 are dissolved (or dispersed) in a solvent (for example, methyl ethyl ketone, cyclopentanone, etc.) to form a slurry. Next, this slurry is set in a coating machine (for example, a doctor blade, a die coater, or a reverse coater), continuously applied onto the film 22, and dried to form composite layers 15 and 16.

  In addition, after apply | coating the slurry which consists of a resin, an inorganic filler, and a solvent at least on the film 22 and drying and forming the 2nd composite layer 16, the same process is repeated, and the 1st composite layer is formed on this. 15 may be formed.

  Alternatively, a plurality of types of slurry comprising at least a resin, an inorganic filler, and a solvent may be simultaneously applied on the film 22 and dried to produce a plurality of composite layers 15 and 16 at a time. In this case, it is desirable that the concentration (or specific gravity or viscosity) of the slurry close to the film 22 is larger than the concentration (or specific gravity or viscosity) of the slurry overlaid thereon. By doing so, the thickness accuracy of each layer when the plurality of composite layers 15 and 16 are formed can be increased. For such applications, a coating machine such as a die coater or a curtain coater can be used.

  The composite layers 15 and 16 are made of a material having a thermal conductivity of 3 W / (m · K) or more and 20 W / (m · K) or less after curing (or after completion as the heat transfer printed wiring board 11). It is desirable to choose. When the heat conductivity after curing is less than 3 W / (m · K), it may be difficult to obtain the effect of heat conduction through the opening 18. A material having a thermal conductivity exceeding 20 W / (m · K) is expensive and may be difficult to handle.

  Here, in order to realize 3 W / (m · K) or more and 20 W / (m · K) or less after curing, it is desirable that the resin is composed of at least a resin and an inorganic filler dispersed in the resin.

  And this resin was selected from epoxy resin, and inorganic filler was selected from alumina, aluminum nitride, boron nitride, silicon carbide, silicon nitride, silica, zinc oxide, titanium oxide, tin oxide, carbon, zircon silicate, magnesium oxide It can be set as the inorganic filler which consists of at least 1 or more types.

  The average particle size of the inorganic filler is preferably in the range of 0.01 μm to 50 μm. Since the specific surface area increases as the average particle size becomes smaller, the heat radiation area increases and the radiation efficiency increases. However, when the average particle size becomes 0.01 μm or less, the specific surface area increases, and dispersion and kneading become difficult. If the thickness exceeds 50 μm, the composite layers 15 and 16 covering the thick copper foil 14 become thick, which may affect the workability of the hole 25 by a laser or the like.

  In order to increase the filling rate of the inorganic filler, a plurality of types of inorganic fillers having different particle size distributions may be selected and used in combination.

(Embodiment 4)
As Embodiment 4, the result of having measured about the bending strength of the heat-transfer printed wiring board 11 demonstrated in Embodiment 1-3 is shown.

  FIG. 8 is a schematic diagram illustrating an example of a bending strength evaluation method. In FIG. 8, 26 is a jig. In FIG. 8, the heat transfer printed wiring board 11 is set between the jigs 26, and the heat transfer printed wiring board 11 is bent using the jig 26 in the direction indicated by the arrow 21. In the experiments by the inventors, the conventional product was broken (broken) when bent by 1 to 2 mm. On the other hand, the heat transfer printed wiring board 11 of the present invention did not break even when bent by 4 to 5 mm. The sample size (heat transfer printed wiring board) is 40 mm × 4 mm × t2 mm.

  As described above, the printed wiring board 24, a laminated composite layer having a thermal conductivity of 3 W / (m · K) or more and 20 W / (m · K) or less formed on one or more surfaces thereof, and the laminated composite layer By providing the heat transfer printed wiring board 11 including the surface layer wiring pattern 17 formed above, it is possible to reduce the size and performance of various electronic devices.

  A printed wiring board 24 in which a glass epoxy resin and a copper foil are laminated, a thick copper foil 14 formed thereon, and a thermal conductivity of 3 W / (m · K) or more and 20 W / (M · K) The laminated composite layer, the surface layer wiring pattern 17 formed on the laminated composite layer, and the thick copper foil 14 and the surface layer wiring pattern 17 through the holes 25 formed in the laminated composite layer. By providing the heat transfer printed wiring board 11 including the blind vias 18 that connect to each other, it is possible to reduce the size and performance of various electronic devices.

  The thickness of the thick copper foil 14 formed on the printed wiring board 24 is the heat transfer printed wiring board 11 having a thickness of 30 microns or more and 120 microns or less, thereby enhancing the diffusion / heat dissipation effect through the thick copper foil 14. Can do.

  The laminated composite layer is formed of a first composite layer 15 made of a resin and an inorganic filler and a second composite layer 16, and only the first composite layer 15 has a thickness of the thick copper foil 14. By making the heat transfer printed wiring board 11 thicker, it is possible to absorb the thickness of the thick copper foil 14 and provide the heat transfer printed wiring board 11 with less unevenness on the surface and excellent mountability.

  The composite layer is formed of the first composite layer 15 made of a resin and an inorganic filler and the second composite layer 16, and the content of the inorganic filler in the first composite layer 15 is 60% by volume. 95% by volume or less, the content of the inorganic filler of the second composite layer 16 is 0% by volume or more and 40% by volume or less, so that the thickness of the thick copper foil 14 can be absorbed. Provided is a heat-transfer printed wiring board 11 with less unevenness on the surface and excellent mountability.

  A laminate composed of at least a first composite layer 15 having an inorganic filler content of 60% by volume to 90% by volume and a second composite layer 16 having an inorganic filler content of 0% by volume to 50% by volume. By using the composite sheet 23, it is possible to absorb the thickness of the thick copper foil 14, and the heat transfer printed wiring board 11 with less unevenness on the surface and excellent mountability is provided.

  A laminated composite sheet 23 made of at least a resin and an inorganic filler and laminated with a first and second composite layer, wherein the first composite layer 15 has a softening temperature higher than that of the second composite layer. By providing the laminated composite sheet 23 having a low temperature in the range of 10 ° C. or more and 200 ° C. or less, the thickness of the thick copper foil 14 can be absorbed, and the heat transfer printed wiring board 11 with less unevenness on the surface and excellent mountability is provided.

  The thickness of the thick copper foil 14 is obtained by applying a slurry comprising at least a resin, an inorganic filler, and a solvent on the film 22 and drying the composite layer 23 a plurality of times. Can be produced stably.

  On the film 22, a plurality of types of slurry composed of a resin, an inorganic filler, and a solvent are simultaneously applied and dried to produce a plurality of composite layers at once. The laminated composite sheet 23 capable of absorbing the thickness can be manufactured stably.

  A step of preparing a printed wiring board 24 having a thick copper foil 14 on the surface layer, a step of fixing a plurality of composite sheets made of at least a resin and an inorganic filler on the printed wiring board 24, and a hole in the composite sheet The method of manufacturing the heat-transfer printed wiring board 11 includes a step of forming a layer 25 and a step of connecting a part of the surface layer wiring pattern 17 formed on the composite sheet to the thick copper foil 14 through the hole 25. Therefore, the heat-transfer printed wiring board 11 can be stably manufactured, so that downsizing and high performance of mobile phones, plasma televisions, electrical equipment, and devices that require industrial heat dissipation can be realized.

  As described above, according to the heat transfer printed wiring board according to the present invention, the heat transfer prepreg used in the heat transfer printed wiring board, and the manufacturing method thereof, a cellular phone, a plasma TV, an electrical component, or an industrial device that requires heat dissipation is required. Miniaturization and high performance are possible.

Sectional drawing of the heat-transfer printed wiring board in Embodiment 1 Sectional drawing explaining the heat transfer mechanism of a heat transfer prepreg Sectional drawing explaining how to laminate a laminated composite material on the surface of a printed wiring board Sectional drawing explaining how to fix a laminated composite sheet on one or more sides of a printed wiring board Sectional drawing explaining the state after integrating the printed wiring board and the laminated composite sheet Sectional drawing explaining how to form holes in the composite layer Sectional drawing explaining how a surface layer wiring pattern is formed on the surface of a composite layer Schematic diagram showing an example of bending strength evaluation method (A) and (B) are cross-sectional views illustrating a state in which a crystalline polymer having a mesogenic group is oriented using a magnetic field to increase the thermal conductivity. Sectional drawing which shows an example of the conventional heat-transfer prepreg which improved the bendability

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Heat transfer printed wiring board 12 Epoxy resin layer 13 Glass fiber 14 Thick copper foil 15 1st composite layer 16 2nd composite layer 17 Surface layer wiring pattern 18 Blind via 19 Electronic component 20 Solder part 21 Arrow 22 Film 23 Laminated composite sheet 24 Printed wiring board 25 Hole 26 Jig

Claims (10)

A printed wiring board;
A laminated composite layer having a thermal conductivity of 3 W / (m · K) or more and 20 W / (m · K) or less formed on one surface or more;
Surface layer wiring pattern formed on this laminated composite layer,
Heat transfer printed wiring board consisting of A printed wiring board formed by laminating a glass epoxy material and a thick copper foil on which a wiring pattern is formed,
A laminated composite layer having a thermal conductivity of 3 W / (m · K) or more and 20 W / (m · K) or less, formed on one or more surfaces thereof;
Surface layer wiring pattern formed on this laminated composite layer,
A blind via connecting the thick copper foil and a surface wiring pattern through a hole formed in the laminated composite layer;
Heat transfer printed wiring board consisting of 3. The heat-transfer printed wiring board according to claim 1, wherein the thick copper foil formed on the printed wiring board has a thickness of 30 to 120 microns. The laminated composite layer is formed of a first composite layer made of a resin and an inorganic filler, and a second composite layer,
The heat transfer printed wiring board according to claim 2, wherein the thickness of the first composite layer is thicker than the thickness of the thick copper foil. The composite layer is formed of a first composite layer made of a resin and an inorganic filler, and a second composite layer,
The content of the inorganic filler in the first composite layer is 60% by volume to 95% by volume,
The heat transfer printed wiring board according to claim 2, wherein the content of the inorganic filler in the second composite layer is 0 volume% or more and 40 volume% or less. at least,
A first composite layer having an inorganic filler content of 60% by volume or more and 90% by volume or less;
A second composite layer having an inorganic filler content of 0% by volume to 50% by volume;
A laminated composite sheet. at least,
A laminated composite sheet comprising a resin and an inorganic filler, wherein the first and second composite layers are laminated,
A laminated composite sheet in which the first composite layer has a softening temperature lower than that of the second composite layer in the range of 10 ° C to 100 ° C. A method for producing a laminated composite sheet in which a step of applying a slurry comprising at least a resin, an inorganic filler, and a solvent on a film and drying to produce a composite layer is repeated a plurality of times. A method for producing a laminated composite sheet in which a plurality of types of slurry comprising a resin, an inorganic filler, and a solvent are simultaneously coated on a film and dried to produce a plurality of composite layers at once. Preparing a printed wiring board having a thick copper foil on the surface layer;
A step of fixing a plurality of composite sheets composed of at least a resin and an inorganic filler on the printed wiring board,
Forming a hole in the composite sheet;
Connecting a portion of the surface wiring pattern formed on the composite sheet to the thick copper foil through the hole;
The manufacturing method of the heat-transfer printed wiring board which has this.

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