JP2006332449A - Multilayer printed wiring board and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make excellent heat radiation characteristics and/or current characteristics, and to achieve weight reduction and high density. <P>SOLUTION: A plurality of piece bodies having heat radiation characteristics and/or current characteristics and an insulating resin formed in the periphery are arranged at an internal layer, and the insulating layer and a conductor layer equipped with a land are laminated on at least either of the upper and lower faces so that a multilayer printed wiring board can be configured. This method for manufacturing the multilayer printed wiring board comprises: a step for laminating the insulating layer and a conductor layer on at least either of the upper and lower faces with a multilayer printed wiring board, where the land is connected through an in-layer connection to the piece bodies (a core substrate constituted of a plurality of piece bodies having heat radiation characteristics and/or current characteristics and an insulating resin part formed in the periphery) as the center; a step for forming the land part in the conductor layer; and a step for connecting the land part to the piece bodies at the inter-layer connection part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multilayer printed wiring board suitable for mounting electronic components that generate heat or for large currents and a method for manufacturing the same.

  In recent years, electronic parts typified by LEDs (light emitting diodes) and the like have been used more than their convenience. However, since electronic components represented by LEDs and the like generate heat, in order for the electronic components to function properly in the electronic device, it is necessary to dissipate the generated heat source with an appropriate medium. .

  2. Description of the Related Art Conventionally, an electronic device generally attempts to solve a heat dissipation problem by configuring a heat sink around a heat-generating component by using a heat-dissipating fin, a fan and a Peltier element or a combination thereof. However, on the other hand, technical development has also been made on a heat radiation type printed wiring board having a so-called heat radiation function, in which the heat generating component mounted on the printed wiring board can be radiated by the printed wiring board itself.

  As the heat radiation type printed wiring board, a printed wiring board having a structure shown in FIG. 7 in which a metal plate 52 such as a copper plate or an aluminum plate is introduced into the inner layer of the printed wiring board has been used. . That is, first, a metal plate 52 is prepared, and an insulating material 51 such as a prepreg and a copper foil are sequentially arranged on the front and back surfaces of the metal plate 52, and are laminated together to form a desired circuit wiring. This is obtained by mounting a component 20 that generates heat.

  The heat radiation function of the heat radiation type printed wiring board shown in FIG. 7 is that, for example, a through hole 10a is disposed as an interlayer connection immediately below the heat generating component 20, and in addition, the through hole 10a is connected to the metal plate 52. It is made up of a configuration that allows As a result, the heat source generated from the component 20 is transmitted to the metal plate 52 through the through hole 10a as shown by the arrow from the component 20 shown in FIG. 7, and the metal plate 52 stores heat or dissipates heat. Alternatively, by connecting a corresponding cooling medium to the metal plate 52, the object of heat dissipation is achieved.

  However, in the heat dissipation type printed wiring board shown in FIG. 7, the metal plate 52 for heat dissipation and heat transfer is disposed over a wide area of the inner layer portion of the printed wiring board. In addition to the problem of increasing, there has been a problem of causing harmful effects on various functions such as higher density and higher functionality of the printed wiring board.

  In addition, when forming the through hole 10b mainly intended for wide electrical connection between layers without the purpose of heat dissipation, an opening 53 is provided in the metal plate 52 in advance as shown in FIG. Therefore, it is necessary to provide the through hole 10b in the opening 53 based on good alignment. This is a consideration for preventing electrical signals from being transmitted and received from the through hole 10b to the metal plate 52 by bringing the through hole 10b and the metal plate 52 into a non-contact state. In other words, these are necessary in terms of structure and process in order to realize various functions of the heat radiation type printed wiring board.

  On the other hand, in view of the above problems, by performing etching-type circuit formation in advance on the metal plate, which is mainly intended for heat dissipation, by reducing the weight of the entire printed wiring board by making smaller pieces, and by making smaller pieces A technology for improving various functions such as high density and high functionality of a printed wiring board by effectively utilizing the vacant space is already known.

  However, it is said that the method of fragmentation by the circuit formation of the metal plate requires a thick metal plate with good thermal conductivity because the metal plate is intended for heat dissipation. The following problems have occurred in circuit formation.

  Hereinafter, the problem in the circuit formation of the thick metal plate will be described with reference to FIG. In FIG. 8A, first, a thick copper foil 54 with good thermal conductivity adhered to the insulating material 55 is prepared. Next, as shown in FIG. 8 (b), an etching resist for circuit formation is applied as a mask 56, and exposure, development, conductor etching, and mask peeling steps are sequentially performed to obtain the circuit shown in FIG. 8 (c). A structure after completion of formation is obtained. However, the structure after the circuit formation is a problem.

  That is, since the structure after the circuit formation shown in FIG. 8C has a thick conductor, it is difficult to sufficiently etch the thick conductor when the circuit is etched. There is a problem in that a hem portion 58 has a problem of skirting and comes into contact with an adjacent circuit.

  In view of the problems caused by etching when such a thick conductor is used, as a method of manufacturing a heat radiation type printed wiring board without using an etching method for forming a heat radiation portion, for example, a power as shown in FIG. A method for producing a printed wiring board having a module structure has already been reported (see Patent Document 1).

  The power module shown in FIG. 9 includes a circuit board 63 in which a reinforcing material is impregnated with a thermosetting resin in advance, and an insulating resin mixture 64 containing an inorganic filler and an insulating resin in an opening formed in the circuit board 63. A filled one is prepared and the insulating resin mixture 64 is used as a heat dissipation medium.

  That is, as shown in FIG. 9A, the lead frame 61 and the metal foil 62 are arranged on the upper surface of the circuit board 63 and the insulating resin mixture 64, and the metal foil 62 is arranged on the lower surface thereof. Then, the structure shown in FIG. 9B is obtained by laminating and pressing. Finally, by forming a circuit on the front and back metal foils 62, a power module having the circuit wiring 65 shown in FIG. 9C is obtained.

  The power module shown in FIG. 9C includes a lead frame 61 suitable for a large current circuit formed in an insulating resin mixture 64 having a high heat dissipation property, and a fine wiring pattern 65 made of a metal foil. A structure in which an insulating resin mixture 64 as a high heat conductive layer with high heat dissipation is provided on a desired portion of the substrate 63, and as a power module, the lead frame is used independently of a place where heat dissipation is required, and is independent. An island-like wiring pattern can be formed, and a fine wiring pattern can be formed in a place where heat radiation is not so necessary.

  However, the power module shown in FIG. 9 has the following problems.

  First, the insulating resin mixture 64 is used as a heat radiating member. However, in order to reliably radiate the heat generated from the components or to move the heat to the back surface, the heat radiating member is weak. Is that copper or a metal species having an equivalent heat transfer characteristic is required.

  Secondly, in order to reliably dissipate the heat generated from the components and to transfer heat to the back surface reliably, a structure that can mount a component that generates heat directly above the heat dissipation member is good. It is difficult to mount a component that generates heat immediately above the insulating resin mixture 64 as a member.

  Third, the heat radiation type power module shown in FIG. 9 uses the insulating resin mixture 64 as a heat radiation member, and the lead frame 61 as a large current circuit, and appropriately uses both in combination or independently to radiate heat. However, it is necessary to pay special attention to the arrangement position, which hinders the design freedom of circuit wiring.

  Fourthly, it is necessary to embed the lead frame 61 in the insulating resin mixture 64 by lamination, but this is difficult. That is, when embedding, the insulating resin mixture 64 requires an organic resin component having a relatively large amount of heat fluidity, while the insulating resin mixture 64 contains a large amount of inorganic filler to dissipate heat. Since it is necessary to contain, the material design of the insulating resin mixture 64 is difficult.

Japanese Patent No. 3214696

  The problem to be solved by the present invention based on such a background is excellent in heat dissipation characteristics and / or large current characteristics, particularly suitable as a multilayer printed wiring board for mounting a component that generates heat, and is lightweight, high density It is another object of the present invention to provide a multilayer printed wiring board that can be manufactured in a short number of steps and a manufacturing method thereof.

  The inventor has made various studies in order to solve the above problems. As a result, a plurality of individual pieces having heat dissipation characteristics and / or current characteristics and insulating resin portions formed around the plurality of pieces are arranged in the inner layer portion, and then the land portion on which the component is mounted, The present invention has been completed by finding that extremely good results can be obtained by using a multilayer printed wiring board in which individual pieces are connected via an interlayer connection portion.

  That is, according to the present invention, a plurality of pieces having heat dissipation characteristics and / or current characteristics and an insulating resin portion formed around the plurality of pieces are disposed in the inner layer portion, and at least one of upper and lower surfaces thereof is insulated. A multilayer printed wiring board in which a conductor layer having a layer and a land portion is formed in a laminated manner, wherein the land portion and the piece are connected via an interlayer connection portion The printed wiring board solves the above problems.

  Further, according to the present invention, a plurality of individual pieces having heat dissipation characteristics and / or current characteristics and an insulating resin portion formed around the individual pieces are arranged in the inner layer portion, and the insulating layer and the land portion are provided on both upper and lower surfaces thereof. A multilayer printed wiring board in which a conductor layer provided is laminated, and a land portion arranged in the uppermost layer of the multilayer printed wiring board is connected to the individual body via an interlayer connection portion The above-mentioned problem is solved by a multilayer printed wiring board characterized in that a land portion arranged in the lowermost layer of the multilayer printed wiring board is connected to the individual piece through an interlayer connection portion.

  Further, the present invention solves the above problems by a multilayer printed wiring board characterized in that at least one of the individual pieces connected to the land part via an interlayer connection part is a terminal part. is there.

  Moreover, this invention solves the said subject with the multilayer printed wiring board characterized by the components being mounted in the said land part.

  Moreover, this invention solves the said subject with the multilayer printed wiring board characterized by the conductor which consists of copper plating being formed in the surface of the said insulating resin part.

  In addition, the present invention solves the above problems by a multilayer printed wiring board characterized in that the insulating resin portion and all the individual pieces are flush with each other on at least one surface.

  Further, the present invention solves the above-described problems by a multilayer printed wiring board, wherein the individual pieces are at least two kinds of individual pieces having different thicknesses.

  Further, the present invention solves the above problems by a multilayer printed wiring board, wherein the individual piece is made of copper, copper alloy, aluminum, aluminum alloy, carbon or a composite material of carbon and metal. is there.

  Moreover, this invention solves the said subject with the multilayer printed wiring board characterized by the thickness of the said piece body being 35 micrometers or more.

  Moreover, this invention solves the said subject with the multilayer printed wiring board characterized by the said insulating resin part being shape | molded with the thermosetting resin.

  Moreover, this invention solves the said subject with the multilayer printed wiring board characterized by the said insulating resin part being shape | molded with the thermoplastic resin.

  Moreover, this invention solves the said subject with the multilayer printed wiring board characterized by the said terminal part being a thermal radiation terminal or an electrical connection terminal.

  In addition, the present invention provides insulation on at least one of the upper and lower surfaces of a core substrate including a plurality of individual pieces having heat dissipation characteristics and / or current characteristics and an insulating resin portion formed around the individual pieces. A step of laminating a layer and a conductor layer, a step of forming a land portion on the conductor layer, and a step of connecting the land portion and the individual piece at an interlayer connection portion. The above-mentioned problems are solved by the manufacturing method of the multilayer printed wiring board which is characterized.

  In addition, the core substrate of the present invention has a step of placing an adhesive sheet on the lower surface of a foil made of a material having heat dissipation characteristics and / or current characteristics, and simultaneously punching the foil with a mold to obtain a piece. Adhering the individual piece to the adhesive sheet, forming an insulating resin portion around the individual piece adhered to the adhesive sheet, and a surface comprising the individual piece and the insulating resin portion. The above-mentioned problems are solved by a method for producing a multilayer printed wiring board, which is produced by a flattening step.

  Further, the core substrate of the present invention further includes a step of forming a conductor made of copper plating on the flattened surface after the flattening step of the surface consisting of the individual pieces and the insulating resin portion. The above-mentioned problems are solved by the manufacturing method of the multilayer printed wiring board which is characterized.

  Moreover, the insulating resin part of the core substrate according to the present invention solves the above problems by a method for manufacturing a multilayer printed wiring board, wherein the insulating resin part is formed of a thermosetting resin.

  In addition, the insulating resin portion of the core substrate of the present invention solves the above problems by a method for producing a multilayer printed wiring board, wherein the insulating resin portion is molded of a thermoplastic resin.

  Further, the core substrate of the present invention has solved the above problems by a method for producing a multilayer printed wiring board, wherein the insulating resin portion is molded by an injection molding method, a compression molding method or a transfer molding method. Is.

  The core substrate of the present invention solves the above problems by a method for producing a multilayer printed wiring board, wherein the surface is flattened by buffing.

  In the multilayer printed wiring board according to the present invention, the individual piece has heat dissipation characteristics and current characteristics, and since the individual piece and the component mounting land portion are connected, heat dissipation to the component or heat transfer to the back surface portion. In addition, it is possible to effectively conduct electrical conduction for the purpose of a large current. And since the said individual piece is arrange | positioned in the core part of a multilayer printed wiring board in the individual state individually, it is lightweight and can be densified. Furthermore, according to the method for producing a multilayer printed wiring board of the present invention, the printed wiring board of the present invention can be efficiently produced with a short number of steps.

  The best mode for carrying out the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic cross-sectional process explanatory diagram showing a first manufacturing method of a core substrate P1 used for an inner core portion (a central portion) in a multilayer printed wiring board of the present invention.

  First, at least one sheet is prepared using the foil 1 as a material. The printed wiring board in the present invention is intended to perform thermal functions such as heat dissipation, heat transfer, and heat storage, and is intended for large current applications. Therefore, the foil 1 has a high thermal conductivity. A material having low property and electrical resistance is preferably used.

  Thus, the material constituting the foil 1 is particularly preferably copper or a copper alloy, or aluminum or an aluminum alloy. When the most important purpose is to fulfill the thermal function, the material constituting the foil 1 is not limited to the copper or aluminum material, but also carbon or a composite of carbon and metal. The material is particularly preferably used. This is because carbon or a composite material of carbon and metal has higher thermal conductivity than the copper or aluminum material.

  In consideration of fulfilling the thermal function such as sufficient heat radiation, the foil 1 preferably has a thickness of 35 μm or more. Thus, the foil 1 in the present invention includes not only what is referred to as a foil but also those referred to as sheets, plates, plates and the like.

  Next, the mold of the foil 1 is processed for the purpose of punching the foil 1. Here, as a die processing method, it can be carried out by using a die frame processing equipment for lead frames which has been conventionally used. At that time, as shown in FIG. 1A, the punching degree in the mold 3 and the stroke and block 3b are used to adjust the punching degree. For example, in order to punch out the individual piece 4 having a good shape and attach the individual piece 4 to the adhesive sheet 2 with good adhesiveness, it is important to set the lowest point of the punch 3a when the foil 1 is punched out. It is. In particular, in order to affix the individual piece 4 to the adhesive sheet 2 with good adhesiveness, 0.05 to 0 further below the lowest point of the punch 3a necessary for punching the foil 1 by adjusting the stroke and block 3b. It is desirable to set the lowest point of the punch 3a within a range of .15 mm, apply a slight amount of pressure to the individual piece 4 with the punch 3a, and affix the individual piece 4 to the adhesive sheet 2 so as to be pressed. If the range is shallow, a positional deviation is likely to occur when the piece 4 is bonded to the adhesive sheet 2. Further, in the present invention, since the individual piece 4 punched by the mold processing of the foil 1 is used in the present invention, the adhesive sheet 2 is disposed on the lower surface of the foil 1 as shown in FIG. It is important to.

  That is, as shown in FIG. 1 (a), an adhesive sheet 2 is disposed on the lower surface of the foil 1, and then the foil 1 is punched out by a mold 3, as shown in FIG. 1 (b). The individual pieces 4 are individually bonded to the adhesive sheet 2 in a floating island state.

  Here, in the present invention, in forming the desired multilayer printed wiring board, the floating island state piece 4 cut by the mold 3 is meaningful.

  The conventional lead frame uses a portion in a frame state that is left after being punched out by the mold, whereas in the present invention, it is different in that the portion of the individual piece 4 punched out by the die is used. . In other words, the lead frame has a frame-like continuity because it uses the remaining part that is punched out, but since the individual pieces 4 in the present invention are independent of each other, heat is dissipated in the individual independent parts. Or the function as a heat transfer or a large-current use can be provided.

  Next, the mold 4 is used around the periphery 4 of the floating island state piece shown in FIG. 1 (b) obtained by the above-described processing by injection molding, compression molding, transfer molding, or the like. As shown in (c), the insulating resin portion 5 is molded. In the present invention, the injection molding method is particularly preferably used because of the advantage that the generation of burrs is small.

  As a material of the insulating resin portion 5, it is preferable to use a thermosetting resin or a thermoplastic resin. Here, as the thermosetting resin, phenol resin and epoxy resin are mainly used, but in addition, polyimide, bismaleimide triazine resin, melamine resin, cyanate resin, benzocyclobutene resin, unsaturated polyester, polybenzoxazole, Polyphenylene ether, polyphenylene oxide, and diallyl phthalate resin can also be preferably used.

  As the thermoplastic resin, polyimide, polyester, liquid crystal polymer, fluororesin, polyether ether ketone, polynorbornene, polyethylene terephthalate, cycloolefin resin, polyphenylene sulfide, polyether sulfone, and acrylic resin are preferably used.

  In addition, in the resin, in order to give rigidity, low gland expansion characteristics and heat dissipation characteristics to the resulting structure, a filler such as alumina or silica is further mixed to improve the function in terms of physical properties. More preferred above.

  When the insulating resin portion 5 is molded by the injection molding method, the molding die is designed so that the individual piece 4 is fixed by a part of the molding die. This is only a state in which the individual piece 4 is temporarily fixed on the adhesive sheet 2, and therefore the individual piece 4 is displaced from a predetermined position when the resin is thermally fluidized by the injection molding method. Because

  Incidentally, when designing the molding die, the insulating resin part 5 of the structure shown in FIG. 1C is formed with a three-dimensional structure by providing irregularities in the molding die. It is also possible, and a printed wiring board having a desired structure can be obtained by appropriately designing the mold.

  In the above injection molding method, the insulating resin portion 5 is formed on the individual piece 4 in the floating island state, so that the individual piece 4 and the insulating resin portion 5 are flush and flat as shown in FIG. A structure is obtained. Next, the core sheet P1 shown in FIG. 1 (d) is obtained by peeling the adhesive sheet 2 from the structure shown in FIG. 1 (c).

  In the above manufacturing process, as the adhesive sheet 2, (i) Adhesive strength sufficient to bond the punched piece 4, (ii) Heat resistance capable of withstanding heat during molding resin processing in injection molding (Iii) Those having good peeling characteristics when obtaining the core substrate P1 are preferable.

  Examples of the adhesive sheet 2 having such characteristics include a heat-foamed adhesive sheet. This heat-foaming type adhesive sheet has an adhesive force for adhering the punched individual piece 4 in a room temperature environment, and foams due to heat during molding resin processing in injection molding. Good peeling characteristics when obtaining Therefore, it is suitably used as the adhesive sheet 2 having the above (i) adhesive strength, (ii) heat resistance, and (iii) good release characteristics.

  In addition, the adhesive sheet 2 is not limited to a single sheet having the heating and foaming characteristics, and the dimensional stability when obtaining the core substrate P1 is improved, so that the area change rate due to shrinkage and expansion is small. It is more desirable to use it as a laminate in which sheets are further bonded.

  The core substrate P1 thus obtained has a flat structure in which the individual pieces 4 and the insulating resin portion 5 are flush with each other on the front and back surfaces. However, when a step occurs at the interface between the individual piece 4 and the insulating resin portion 5, the surface is appropriately flattened by buffing or the like.

  Here, the buff polishing is performed under relatively gentle polishing conditions because the individual piece 4 and the insulating resin portion 5 are bonded only on the side surface of the individual piece 4 in the core substrate P1. For example, for the purpose of cutting the residue due to the step of the core substrate P1, it is preferable to perform the buffing with the polishing current value set to 0.5 (A) or less.

  A feature of the core substrate P1 shown in FIG. 1 (d) is that the individual piece 4 arranged in the core substrate P1 serves as a heat dissipation use or a large current use, and the conventional printed wiring shown in FIG. It can be used as a substitute for the metal plate 52 in the plate, and has a feature that the piece 4 can be provided only at a desired location, so that it has a structure that can solve the problems of the prior art. It is.

  That is, the metal plate 52 in the printed wiring board shown in FIG. 7 played a role as a heat dissipation application or a large current application. However, as described in the problems of the prior art, the metal plate 52 is a printed wiring board. Since the inner layer portion of the printed wiring board is disposed in a wide range, the weight of the entire printed wiring board is increased, and in addition, various functions such as higher density and higher functionality of the printed wiring board may be adversely affected. In addition, when forming the through-hole 10b which is not intended for heat dissipation but mainly intended for electrical connection, an opening 53 is provided in the metal plate 52 in advance as shown in FIG. Therefore, it is necessary to provide the through hole 10b in the opening 53 based on the above.

  On the other hand, in the core substrate P1 shown in FIG. 1 (d), since the individual pieces 4 are made of a thick copper member or the like, the individual pieces 4 are used for heat dissipation or large current use. Can play a role. In addition, since the individual piece 4 has the selectivity of the arrangement position, the individual piece 4 can be appropriately arranged only in a desired place requiring a heat radiation use or a large current use.

  Further, since the insulating resin portion 5 which is lighter than the metal body is formed around the individual piece body 4, the weight of the entire printed wiring board can be reduced. In addition, by forming a circuit by plating on the core substrate P <b> 1 described later, a printed wiring board having a high density and high function can be obtained. Furthermore, when forming the through hole 10b as shown in FIG. 7 which is the prior art, if the through hole 10b is formed in the insulating resin portion 5 portion, electrical contact with the individual piece 4 is achieved. Disappears. Therefore, there is no need to provide the opening 53 in the metal plate 52 in advance as shown in FIG.

  Next, FIG. 2 is a schematic cross-sectional process explanatory diagram showing a second manufacturing method of the core substrate P2 used for the inner core portion (the central portion) in the multilayer printed wiring board of the present invention.

  First, at least one or more sheets are prepared using different thickness foils, that is, relatively thin foil and relatively thick foil as materials. The multilayer printed wiring board according to the present invention is intended to perform thermal functions such as heat dissipation use, heat transfer use, and heat storage use, and is intended for large current use. Therefore, the foil has high heat conduction. A material having low property and electrical resistance is preferably used.

  Thus, as a material constituting the foils having different thicknesses, copper or a copper alloy or aluminum or an aluminum alloy is particularly preferable. In addition, when the most important purpose is to fulfill the thermal function, as a material constituting the foil of different thickness, in addition to the copper or aluminum material, carbon or carbon and metal These composite materials are particularly preferably used. This is because carbon or a composite material of carbon and metal has higher thermal conductivity than the copper or aluminum material.

  In consideration of fulfilling the thermal function such as sufficient heat dissipation, it is preferable to use a foil having a thickness of 35 μm or more. Thus, the foil includes not only what is referred to as a foil but also an embodiment referred to as a sheet, plate, plate, or the like.

  In addition, the thickness of the foils having different thicknesses is more preferably selected from those having a thickness of 35 μm or more. For example, a 100 μm product is used as a thin foil, and a 750 μm product is used as a thick foil. Use one that is suitable for the intended use of the printed wiring board.

  Next, for the purpose of punching the foil, the foils having different thicknesses are processed. Here, as a die processing method, it can be carried out by using a die frame processing equipment for lead frames which has been conventionally used. Further, in the present invention, in the present invention, since individual pieces punched by die processing of foils having different thicknesses are used, similar to the embodiment described in the description of FIG. It is important to arrange the adhesive sheet 2 on the lower surface.

  As the mold processing method, as in the embodiment described in the description of FIG. 1 (a), a method of bonding an individual piece punched out by mold processing to the adhesive sheet 2 is performed. Punching is performed with a thin foil mold, and only the punched individual piece 7 is bonded to the adhesive sheet 2 as shown in FIG.

  Next, after adjusting so that the position where the foil is stuck is not displaced, a relatively thick foil mold is punched to bond the punched piece 4 to the adhesive sheet 2, and FIG. As shown in a), both the individual piece 7 (relatively thinner) and the individual piece 4 (relatively thicker) are bonded to the adhesive sheet 2.

  Next, using a molding die, for example, by an injection molding method, around the floating island-shaped piece 7 and piece 4 shown in FIG. The resin part 5 is molded. As the material of the insulating resin portion 5, a thermosetting resin or a thermoplastic resin is preferably used as in the embodiment described in the explanation of FIG.

  By molding the insulating resin portion 5 on the floating island-like piece 7 and the piece 4 by the injection molding method, the piece 4, the piece 7, and the insulating resin portion on the adhesive sheet 2 side. The structure shown in FIG. 2B is obtained, in which the single-piece body 4 and the insulating resin portion 5 are flush with each other on the opposite side. Next, the adhesive sheet 2 is peeled off from the structure shown in FIG. 2B, and the front and back are reversed to obtain the core substrate P2 shown in FIG.

  The core substrate P2 thus obtained has a single-sided structure 4 and an insulating resin portion 5 on both the front and back surfaces (upper and lower sides in the drawing), and the surface (upper surface in the drawing). Thus, the individual body 4, the individual body 7, and the insulating resin portion 5 are flush with each other. However, in the case where a step is generated at the interface between the individual pieces 4 and 7 and the insulating resin portion 5 or the like, the surface is appropriately flattened by buffing or the like.

  The core board P2 shown in FIG. 2 (c) has the main role of the wiring circuit in addition to the single body 4 mainly used for heat radiation of the heat-generating component, heat transfer to the back surface portion, or large current application. The individual piece 7 is formed in a flush state on the surface of the same layer.

  FIG. 3 is a schematic cross-sectional explanatory diagram showing a structural example in which lands and circuit wirings are further formed on the surfaces of the core substrate P1 and the core substrate P2 obtained previously.

  In the structure shown in FIG. 3A, the core substrate P1 obtained above is subjected to copper plating using chemical copper and electrolytic copper sequentially, and further subjected to heat treatment, and then the copper plating is formed into a circuit. As a result, the land portion 8 connected to the individual piece 4 and the conductor 9 mainly used for circuit wiring or the like are provided.

  Here, the circuit can be formed by a conventional circuit forming method such as a subtractive method using a dry film etching resist or an electrodeposition resist. For example, as a circuit forming method, after roughening the surface of the copper plating, a dry film etching resist is laminated on the copper surface, and then exposed to ultraviolet light and developed with an aqueous sodium carbonate solution in an exposure machine. After etching using the ferric solution, the dry film etching resist is peeled off to form the land 8 and the conductor 9 to obtain the printed wiring board shown in FIG.

  On the other hand, in the structure shown in FIG. 3B, the previously obtained core substrate P2 is subjected to copper plating using chemical copper and electrolytic copper sequentially, and then the copper plating is performed, as shown in FIG. In the same manner as the circuit formation in the structure shown in FIG. 2, the circuit is formed to include the land portion 8 connected to the individual piece 4 and the conductor 9 mainly used for circuit wiring or the like.

  The structures shown in FIGS. 3A and 3B thus obtained are (i) stamped out of foil, (ii) processed with molding resin, and (iii) formed circuit wiring on the surface layer. Therefore, the multilayer printed wiring board of the present invention can be manufactured particularly advantageously in the case of industrial mass production.

  FIG. 4 shows the multilayer substrate of the present invention in which the core substrate P1 or the core substrate P2 obtained previously is used as an inner layer material, and at least one insulating layer and a conductor layer are alternately stacked on each of the layers. It is a schematic sectional explanatory drawing of a printed wiring board. Hereinafter, the manufacturing method of the multilayer printed wiring board of this invention shown by FIG. 4 is demonstrated.

  First, the core substrate P1 or the core substrate P2 shown in FIGS. 1 to 3 is prepared as an inner layer member to be disposed in the inner layer. Here, an example in which the core substrate P1 is used as an inner layer member disposed in the inner layer is shown in FIG.

  The core substrate P <b> 1 used here needs to have the individual pieces 4, but the land portions 8 may or may not be attached to the individual pieces 4. Each can be selected and used according to the structure of the printed wiring board. Therefore, there are the individual pieces 4 to which the land portions 8 are attached and the individual pieces 4 to which the land portions 8 are not attached. In order to distinguish these individual pieces 4 from each other, FIG. In the core substrate P1 shown in FIG. 4A, the former is expressed as an individual piece 4a, and the latter is expressed as an individual piece 4b.

  Next, the core substrate P1 is used as an inner layer material, arranged so that the core substrate P1 is at the center, and the insulating layer 16 and the conductor layer are stacked on the front and back surfaces by stacking, and then etched. By forming the component mounting pad 13, a printed wiring board having a multilayer structure having a four-layer structure composed of L 1 to L 4 shown in FIG. 4A is formed.

  Next, in order to obtain heat transfer and conduction in the interlayer portion, the interlayer connection via 11a and the through hole 10 are provided at desired locations. As the interlayer connection via 11a in the multilayer printed wiring board shown in FIG. 4A, the interlayer connection via 11a provided for the purpose of electrical connection from the L1 layer on which the component 20 is mounted to the L2 layer, or in particular, For the purpose of heat transfer from the component 20 that generates heat to the individual piece 4, there is an interlayer connection via 11 a that connects the component 20 and the individual piece 4.

  As a connection method of the interlayer connection via 11a, a method of connecting to the land portion 8 attached to the individual piece 4a shown in FIG. 4A or a connection to a conductor portion other than the land portion 8 of the L2 layer is used. However, the interlayer connection via 11a may be directly connected to the individual piece 4. This is because heat transfer and conduction in the target interlayer can be formed. Furthermore, since the interlayer connection via 11a is mainly intended for heat transfer and conduction in the interlayer portion, it may be provided between the L3 layer and the L4 layer.

  Similarly, the through hole 10 is provided in the interlayer part mainly for the purpose of heat transfer and conduction in the interlayer part. Here, the through hole 10 is mainly arranged in a structure connecting the uppermost layer and the lowermost layer of the multilayer printed wiring board, and the inside of the through hole 10 may be filled with insulating resin or metal, etc. It may be in a state without. For example, as shown in FIG. 4A, the uppermost L1 layer mounting land on which the component 20 is mounted is connected to the lowermost L4 layer as a structure penetrating the piece 4b. It is preferable to provide the through hole 10. Thereby, the heat source generated from the component 20 can be transferred to the individual piece 4 b through the through hole 10. Further, when connecting to the lowermost L4 layer, the heat radiation function can be improved by providing a cooling medium or the like in the L4 layer portion.

  As described above, the multilayer printed wiring board according to the present invention can be easily connected to the individual pieces 4 by appropriately using interlayer connection vias and through holes, and is intended for heat dissipation and large current use. It has the characteristic that the said piece 4 can be provided only in a desired location. Thereby, a multilayer printed wiring board can be lightweight and can be densified, and can be manufactured in a short process.

  On the other hand, since the interlayer connection via 11a is intended to form heat transfer and conduction in the interlayer portion, a large heat transfer capacity and a large current conduction capacity may be required as the capacity. In such a case, as shown in FIG. 4B, the above object can be easily achieved by providing an interlayer connection via 11b larger than the interlayer connection via 11a.

  Thus, the multilayer printed wiring board of the present invention exhibits both heat radiation characteristics and large current characteristics by the single piece 4 and one connection structure combining the interlayer connection vias and through holes connected thereto. Therefore, there is no need to use them in particular, and there is an advantage that circuit wiring can be designed without special consideration for the arrangement position.

  Further, the individual piece 4 can be easily formed in a desired size depending on the thickness and the punching area, and thereby, the thermal and electrical capacity values can be designed. In addition, as described above, since the capacitance value of the interlayer connection via connected to the piece 4 can be designed in the same manner, it is possible to solve the conventional problem in which the material design is difficult.

FIG. 5 shows the use of the previously obtained core substrate P1 or core substrate P2 as the inner layer material, and when the insulating layer and the conductor layer are alternately laminated at least one layer each, FIG. 4 is a schematic cross-sectional explanatory view of the multilayer printed wiring board of the present invention in which the terminal portion 15 protrudes from the main skeleton of the multilayer printed wiring board by providing a cutout part in part.
Hereinafter, the manufacturing method of the multilayer printed wiring board of this invention shown by FIG. 5 is demonstrated.

  The terminal portion 15 shown in FIG. 5A can be easily formed in the method for manufacturing a multilayer printed wiring board according to the present invention. That is, the individual pieces 4 can be formed in a desired large size in advance, and then laminated in a state where the insulating layer 16 and a part of the conductor layer are provided with a cutout portion in advance.

  A characteristic of the terminal portion 15 is that it has the function of the individual piece 4. That is, as described above, the individual piece 4 can exhibit both heat dissipation characteristics and large current characteristics by one connection structure in which interlayer connection vias and through holes to be connected are combined. The part 15 also has heat dissipation characteristics and large current characteristics. In addition, since the terminal portion 15 is a structure protruding from the main skeleton of the multilayer printed wiring board, the terminal portion 15 has a feature that can be used as an external heat dissipation terminal or an external electrical connection terminal of the multilayer printed wiring board.

  Further, when the terminal portion 15 is used as an external heat dissipation terminal or external electrical connection terminal of a multilayer printed wiring board, a structure in which one surface of the terminal portion 15 is fixed with an insulating material 16 as shown in FIG. The body is advantageous in terms of stability and use.

  The terminal portion 15 as shown in FIG. 5 (b) is provided with a cutout on either the front or back surface when the insulation layer 16 and a part of the conductor layer are previously provided with a cutout. It can be formed easily by stacking.

  Furthermore, as a method of using the terminal portion 15, for example, the multilayer printed wiring board shown in FIG. 5 can be used as a plug-in type terminal structure as shown in FIG. .

  As described above, when the multilayer printed wiring board of the present invention is used, the conventional problems can be solved. In particular, it is excellent in heat dissipation and large current characteristics, is lightweight, and can be densified. Moreover, according to the manufacturing method of the present invention, such an excellent multilayer printed wiring board can be efficiently manufactured in a short process.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional process explanatory diagram illustrating a first manufacturing example of a core substrate used in a multilayer printed wiring board according to the present invention. The schematic cross-sectional process explanatory drawing which shows the 2nd manufacturing example of the core board | substrate used for the multilayer printed wiring board of this invention. The schematic cross-section explanatory drawing which shows the other structural example of the core board | substrate used for the multilayer printed wiring board of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Schematic cross-sectional explanatory drawing which shows the example of the multilayer printed wiring board of this invention. The schematic cross-section explanatory drawing which shows the other example of the multilayer printed wiring board of this invention. Explanatory plane explanatory drawing which shows the example of a terminal part of the multilayer printed wiring board of this invention. Schematic cross-sectional explanatory drawing of the conventional printed wiring board. The schematic cross-sectional process explanatory drawing which shows the example of manufacture of the printed wiring board by a conventional method. The schematic cross-sectional process explanatory drawing which shows the manufacture example of the printed wiring board by another conventional method.

Explanation of symbols

1: Foil 2: Adhesive sheet 3: Mold 4: Individual piece 5: Insulating resin portion 7: Individual piece 8: Land portion 9: Conductors 10, 10a, 10b: Through holes 11, 11a, 11b: Interlayer connection Via 13: Pad portion 15: Terminal portion 16: Insulating layer 20: Component 51: Insulating material 52: Metal plate 53: Opening 54: Copper foil 55: Insulating material 56: Mask 57: Circuit 58: Bottom portion 61: Lead frame 62: Metal foil 63: Circuit board 64: Insulating resin mixture 65: Wiring pattern P1: Core board P2: Core board

Claims (20)

  A plurality of individual pieces having heat dissipation characteristics and / or current characteristics and an insulating resin portion formed around the individual pieces are arranged in the inner layer portion, and at least one of the upper and lower surfaces thereof has an insulating layer and a land portion. A multilayer printed wiring board in which a conductor layer is laminated and the land portion and the individual body are connected via an interlayer connection portion.   A plurality of individual pieces having heat dissipation characteristics and / or current characteristics and an insulating resin portion formed around the individual pieces are disposed in the inner layer portion, and a conductor layer having insulating layers and land portions on both upper and lower surfaces thereof. A multilayer printed wiring board formed by lamination, wherein a land portion arranged in the uppermost layer of the multilayer printed wiring board is connected to the individual body via an interlayer connection portion, and the multilayer printed wiring board 2. The multilayer printed wiring board according to claim 1, wherein a land portion arranged in the lowermost layer is connected to the individual piece through an interlayer connection portion.   3. The multilayer printed wiring board according to claim 1, wherein at least one of the individual pieces connected to the land portion via an interlayer connection portion is a terminal portion. 4.   The multilayer printed wiring board according to claim 1, wherein a component is mounted on the land portion.   The multilayer printed wiring board according to claim 1, wherein a conductor made of copper plating is formed on a surface of the insulating resin portion.   The multilayer printed wiring board according to any one of claims 1 to 5, wherein the insulating resin portion and all of the individual pieces are flush with each other at least on one surface.   The multilayer printed wiring board according to claim 1, wherein the individual pieces are at least two kinds of individual pieces having different thicknesses.   The multilayer printed wiring board according to claim 1, wherein the individual piece is made of copper, a copper alloy, aluminum, an aluminum alloy, carbon, or a composite material of carbon and metal.   The multilayer printed wiring board according to claim 1, wherein the individual piece has a thickness of 35 μm or more.   The multilayer printed wiring board according to claim 1, wherein the insulating resin portion is formed of a thermosetting resin.   The multilayer printed wiring board according to claim 1, wherein the insulating resin portion is formed of a thermoplastic resin.   The multilayer printed wiring board according to claim 3, wherein the terminal portion is a heat radiating terminal or an electrical connection terminal.   Centering on a core substrate consisting of a plurality of individual pieces having heat dissipation characteristics and / or current characteristics and an insulating resin portion formed around the individual pieces, an insulating layer and a conductor layer are provided on at least one of the upper and lower surfaces thereof. A multilayer printed wiring comprising: a step of forming a layer; a step of forming a land portion in the conductor layer; and a step of connecting the land portion and the individual piece at an interlayer connection portion. A manufacturing method of a board.   A step of placing an adhesive sheet on the lower surface of a foil made of a material having a heat dissipation characteristic and / or a current characteristic, and punching the foil with a mold to obtain a single piece, and simultaneously applying the core substrate to the adhesive sheet A step of bonding the individual pieces, a step of forming an insulating resin portion around the individual pieces bonded to the adhesive sheet, and a step of flattening a surface comprising the individual pieces and the insulating resin portion. The method for producing a multilayer printed wiring board according to claim 13, wherein the method is produced by the following method.   15. The multilayer print according to claim 14, further comprising a step of forming a conductor made of copper plating on the flattened surface after the step of flattening the surface comprising the individual pieces and the insulating resin portion. A method for manufacturing a wiring board.   The method for producing a multilayer printed wiring board according to any one of claims 13 to 15, further comprising a step of mounting a component on the land portion.   The method for manufacturing a multilayer printed wiring board according to any one of claims 13 to 16, wherein the insulating resin portion is formed of a thermosetting resin.   The method for manufacturing a multilayer printed wiring board according to any one of claims 13 to 16, wherein the insulating resin portion is formed of a thermoplastic resin.   The method for producing a multilayer printed wiring board according to any one of claims 13 to 18, wherein the insulating resin portion is molded by an injection molding method, a compression molding method or a transfer molding method.   The method for producing a multilayer printed wiring board according to any one of claims 14 to 19, wherein the flattening of the surface comprising the individual pieces and the insulating resin portion is performed by buffing.

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