JP2002271028A - Coil-incorporated multi-layer substrate and its manufacturing method, and manufacturing method for laminated coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently manufacture a coil-incorporated multi-layered resin board which has a relatively large-sized coil. SOLUTION: A coil-incorporated multi-layered resin 29 is formed by laminating insulating resin layers 36 alternately with coil patterns 37 and uniting them together by heating and pressing them, and the coil patterns 37 of respective layers are electrically connected by a via hole conductor 38 formed penetrating the respective insulating resin layers 36. Each insulating resin layer 36 is formed of mixed resin of 65 to 35 wt.% polyaryl ketone resin of >=260 deg.C in crystal fusion peak temperature and 35 to 65 wt.% polyether imide as a crystallized delay polymer. The coil patterns 37 are formed by a subtractive method. The via hole conductor 38 is formed by charging conductor paste in the via hole 39 formed in the insulating resin layers 36 by screen printing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil-embedded multilayer substrate incorporating a coil, a method of manufacturing the same, and a method of manufacturing a laminated coil.

[0002]

2. Description of the Related Art Generally, an electric / electronic circuit device is constructed by mounting various circuit elements on a circuit board. Electrical·
Some electronic circuits include relatively large transformer coils, choke coils, etc. in addition to IC chips, resistors, capacitors, etc. Conventionally, these relatively large coil components are also used on circuit boards. It is arranged on the upper surface in a plane with other circuit elements such as an IC chip.

[0003]

As described above, conventionally, a relatively large coil component is mounted on a single circuit board.
Since the circuit board is arranged side by side with other circuit elements such as a C chip, the surface mounting area of the circuit board becomes large, and demands for miniaturization and high-density mounting, which are important technical issues in recent years, are increasing. Can not meet.

The circuit board itself can be reduced in size by using a multilayer printed wiring board, a resin multilayer board, a ceramic multilayer board, or the like. However, if a relatively large coil component is to be mounted on the board, the circuit board cannot be used. The surface mounting area must be increased accordingly. Conventional multilayer boards have built-in resistors and capacitors in addition to wiring patterns.
There is no one that incorporates relatively large coil components such as a transformer coil and a choke coil.

The present invention has been made in view of such circumstances, and has as its object to provide a coil capable of satisfying demands for miniaturization and high-density mounting by incorporating a relatively large coil in a substrate. An object of the present invention is to provide a built-in multilayer substrate, a method for manufacturing the same, and a method for manufacturing a laminated coil.

[0006]

In order to achieve the above object, a multilayer board with a built-in coil according to the present invention is formed by a resin multilayer board in which a plurality of insulating resin layers are alternately laminated with a coil pattern and integrated. It is preferable that the coil patterns of the respective layers are electrically connected by via-hole conductors formed through the respective insulating resin layers. In this way, a multilayer substrate with a built-in coil can be manufactured by applying the multilayer technology of the resin substrate, and the number of coil turns can be increased by increasing the number of coils, so that a relatively large coil can be mounted on the substrate. Can be built-in.

Further, when manufacturing a multilayer substrate with a built-in coil, it is preferable that a plurality of insulating resin layers are collectively heated and pressed to be integrated. By doing so, the number of steps can be significantly reduced as compared with the method of sequentially stacking the insulating resin layers one by one, and a multilayer substrate with a built-in coil can be manufactured efficiently.

When a plurality of insulating resin layers are collectively heated and pressed to produce a multilayer substrate with a built-in coil, the following conditions are required for the resin material forming the insulating resin layer. (1) High heat-resistant thermoplastic resin that can be heat-pressed together. (2) Satisfies the requirements of environmental protection and recyclability. (3) For heat treatment during temporary joining of conductor foil for coil pattern formation. Even so, the uncured portion can be left. (4) The allowable range of conditions (temperature, time) when heat-pressing multiple insulating resin layers at once is as wide as possible, and production constraints are reduced. (5) Mechanical properties (toughness, etc.) required for circuit boards,
Satisfy the conditions of electrical properties (insulation, low dielectric constant, etc.) and chemical properties (chemical resistance, etc.) Polyarylketone is a highly heat-resistant thermoplastic resin that satisfies the conditions (1) to (5). It is preferable to use a mixed resin of a resin and polyetherimide.

Representative examples of the polyarylketone resin which is a high heat-resistant thermoplastic resin include polyetheretherketone (hereinafter referred to as "PEEK"), polyetherketone, and polyetherketoneketone. FIG.
Shows the results of a test conducted by the present inventors to evaluate the moldability (heat-compression bonding property) of PEEK.

[0010] PEEK is essentially a crystalline resin, and crystallized PEEK exhibits stable elastic modulus characteristics even beyond the glass transition point. Therefore, PEEK has a temperature range below the melting point (160 to 3) even when heated beyond the glass transition point.
(50 ° C), high rigidity, not moldable (no heat compression bonding)
It is. Moreover, if the melting point of the PEEK exceeds the melting point, the fluidity becomes too high to maintain a constant shape, so that it can be molded only in a very narrow temperature range around 360 ° C. slightly above the melting point (heat-compression bonding is possible). .

However, in an actual mass production line, it is difficult to perform thermocompression bonding while maintaining the PEEK temperature in a very narrow temperature range around 360 ° C., which is not suitable for mass production.
In order to realize mass production, it is necessary to make the allowable range of the temperature at the time of thermocompression bonding as wide as possible. For this reason, in the present invention, a polyetherimide as a crystallization retardation polymer is added to amorphous PEEK. (Hereinafter referred to as “PEI”) to form an insulating resin layer with a resin material having a reduced crystallization rate.

That is, although PEEK is intrinsically crystalline, it is made amorphous by a quenching method or the like, and then heated above the glass transition point, as shown in FIG. During the transformation, the elastic modulus of the resin decreases to a relatively soft elastic modulus suitable for molding (heat compression bonding). Since this elastic modulus lowering temperature region is expanded by the blending of PEI which is a crystallization retarding polymer, if this elastic modulus lowering temperature region is used as a thermocompression bonding temperature region, in an actual mass production line,
A plurality of insulating resin layers can be heated and pressed at once.

In manufacturing this multilayer board with a built-in coil, a coil pattern is formed on a plurality of insulating resin layers by a printed wiring method, a via hole is formed at a predetermined position on the plurality of insulating resin layers, and a conductive paste is formed on the via hole. Is filled to form a via-hole conductor, and then a plurality of insulating resin layers are laminated, and then heat-compression-bonded at a time to integrate them.

In such a manufacturing method, since the coil pattern is formed by the printed wiring method which is excellent in mass productivity, the coil pattern can be formed efficiently. Moreover,
Since the conductive paste is filled into the via hole formed in the insulating resin layer to form the via hole conductor, the via hole conductor can be efficiently formed by screen printing excellent in mass productivity. Furthermore, since a plurality of insulating resin layers are collectively heat-pressed, the number of steps can be greatly reduced as compared with a method in which the insulating resin layers are sequentially stacked one by one. Can be manufactured well.

As a printed wiring method used for forming a coil pattern, a subtractive method (also referred to as a photoetching method) in which a conductor foil is attached to the surface of an insulating resin layer and etched to form a coil pattern.
Is suitable for mass production, and the subtractive method is
As compared with the additive method (also called a plating method), the thickness (conductor cross-sectional area) of the coil pattern can be increased, and there is an advantage that the allowable maximum current value can be increased.

In this case, a plurality of insulating resin layers are molded from a mixed resin of a polyarylketone resin and a polyetherimide, and in the process, the polyarylketone resin is made amorphous, and then, in a heating and pressing step, It is preferable that a plurality of insulating resin layers be collectively heat-pressed in a temperature region where the polyaryl ketone resin changes from amorphous to crystalline.
In this way, the allowable range of the temperature at the time of thermocompression bonding can be widened, and mass production is easy.

Before laminating a plurality of insulating resin layers,
It is preferable to flatten the surface of each insulating resin layer on which the coil pattern is formed by pressing. By doing so, there is no step between the resin surface of the insulating resin layer and the surface of the coil pattern. The adhesive strength is increased, and delamination can be more reliably prevented.

Alternatively, after forming an insulating resin layer on the conductor plate by laminating the conductor plate and the insulating resin layer, a via hole is formed at a predetermined position of the insulating resin layer on the conductor plate, and the via hole is filled with a conductive paste. Then, a via hole conductor is formed, and then the insulating resin layer of the conductor plate is punched into a coil pattern shape to form a coil pattern with a plurality of insulating resin layers, and the coil patterns with the plurality of insulating resin layers are laminated. Then, the laminated coil may be manufactured by heat-pressing and integrating all at once. This makes it possible to efficiently manufacture a laminated coil in which the insulating layer is formed of resin. Moreover, since the coil pattern is formed by punching, the thickness (conductor cross-sectional area) of the coil pattern can be increased as compared with the case where the coil pattern is formed by a printed wiring method.
There is an advantage that the allowable maximum current value can be increased.

Also in the case of manufacturing this laminated coil, the insulating resin layer is molded from a mixed resin of a polyarylketone resin and polyetherimide, and in the process, the polyarylketone resin is made amorphous and then heated. In the pressure bonding step, it is preferable that a coil pattern with a plurality of insulating resin layers is collectively heated and pressed in a temperature region where the polyarylketone resin changes from amorphous to crystalline to produce a laminated coil. In this way, the allowable range of the temperature at the time of thermocompression bonding can be widened, and mass production is easy.

Further, it is preferable that the surface of the conductor plate is roughened. By this surface roughening treatment, the adhesive strength between the insulating resin layer and the coil pattern (conductor plate) can be increased, and peeling of both can be more reliably prevented.

The laminated coil may be mounted on another circuit board by soldering or the like. However, the laminated coil is housed in a molding die, and an insulating resin is injected into the molding die to form the coil. A built-in multilayer substrate may be manufactured.
This makes it possible to efficiently manufacture a coil-embedded multilayer substrate having a large coil pattern thickness (conductor cross-sectional area).

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment (1)] An embodiment (1) of the present invention will be described below with reference to FIGS.
First, the configuration of the coil-containing multilayer resin substrate 29 of the present embodiment (1) will be described with reference to FIGS. As shown in FIG. 1 and FIG.
It is formed, for example, in an annular shape by a manufacturing method described later, and includes a choke coil 30, an ignition coil 31 (also called a high-voltage coil) and a DC / DC converter coil 32 in its inner layer. Each coil 30-32
May be only one each, but two or more may be formed in order to secure the number of windings. The coil-containing multilayer resin substrate 29 has through holes 30a to 32a formed in portions located at the inner diameters of the coils 30 to 32, and cores 33 to 35 are mounted in the through holes 30a to 32a.

The multilayer resin substrate 29 with a built-in coil is shown in FIG.
As shown in FIG.
32, which are laminated alternately with the coil patterns 37, and are integrated by heating and pressing, and the coil patterns 37 of the respective layers are formed in via-hole conductors 38 formed through the respective insulating resin layers 36.
Are electrically connected to each other. Each insulating resin layer 36
Polyarylketone resin having a crystal melting peak temperature of 260 ° C. or higher: 65 to 35% by weight, and polyetherimide (hereinafter referred to as “PEI”) which is a crystallization retardation polymer:
It is formed of a mixed resin of 35 to 65% by weight.
The polyarylketone resin is a high heat-resistant thermoplastic resin, for example, polyetheretherketone (hereinafter “PE”).
EK), polyetherketone, polyetherketoneketone, or the like.

On the other hand, the coil pattern 37 is formed by a subtractive method (also called a photo-etching method), which is one of the printed wiring methods, and a conductive foil 45 such as an aluminum foil or a copper foil is formed on the surface of the insulating resin layer 36. (See FIG. 6) is adhered by heat fusion or the like and etched to form a coil pattern 37. The via-hole conductor 38 is formed by filling a via-hole 39 formed in the insulating resin layer 36 with an Ag-based conductor paste such as Ag-Sn by screen printing.

In this embodiment (1), the choke coil 30, the ignition coil 31, and the DC / DC converter coil 32 are all incorporated in the coil-containing multilayer resin substrate 29, but two or one of them is provided. Only the coil may be incorporated. Further, an inner layer wiring pattern other than the coil, a resistor, and a capacitor may be formed in the inner layer of the coil-containing multilayer resin substrate 29. The shape of the coil-containing multilayer resin substrate 29 is not limited to an annular shape, and may be, for example, a square shape, a hexagon shape, or the like, and may be formed in any shape according to the specifications of the headlamp.

When a plurality of insulating resin layers 36 are collectively heated and pressed to produce the coil-containing multilayer resin substrate 29, the following conditions are required for the resin material forming the insulating resin layers 36. .

(1) It is a high heat-resistant thermoplastic resin that can be heated and pressed together. (2) It meets the requirements of environmental protection and recyclability. (3) The conductive foil 45 for forming the coil pattern 37 is formed. The uncured portion can be left even in the heat treatment at the time of temporary joining. (4) The allowable range of conditions (temperature, time) when heat-pressing a plurality of insulating resin layers 36 at once is set as wide as possible. (5) Mechanical properties (toughness, etc.) required for circuit boards,
Satisfy the requirements of electrical properties (insulation, low dielectric constant, etc.) and chemical properties (chemical resistance, etc.)

In this embodiment (1), these (1) to (5)
Polyarylketone resin such as polyetheretherketone (PEEK) having a crystal melting peak temperature of 260 ° C. or higher as a highly heat-resistant thermoplastic resin satisfying the following conditions: 65-3
5% by weight and polyetherimide (PEI): 35 to 6
A mixed resin with 5% by weight is used. FIG. 4 shows the results of a test conducted by the present inventors to evaluate the moldability (heat-compression bonding property) of PEEK.

PEEK is a crystalline resin by nature, and crystallized PEEK shows stable elastic modulus characteristics even beyond the glass transition point. Therefore, as shown in FIG.
Even when K is heated beyond the glass transition point, it has high rigidity in a temperature range below the melting point (160 to 350 ° C.) and cannot be molded (heat and pressure bonding is impossible). Moreover, if the melting point of the PEEK exceeds the melting point, the fluidity becomes too high to maintain a constant shape, so that it can be molded only in a very narrow temperature range around 360 ° C. slightly above the melting point (heat-compression bonding is possible). .

However, in an actual mass production line, it is difficult to perform thermocompression bonding while maintaining the temperature of PEEK in an extremely narrow temperature range of about 360 ° C., which is not suitable for mass production.
In order to realize mass production, it is necessary to widen the allowable range of the temperature at the time of thermocompression bonding. For this reason, in the present embodiment (1), the amorphous PEEK is used as a crystallization retarding polymer. The insulating resin layer 36 is formed of a resin material in which the crystallization speed is reduced by blending PEI.

That is, although PEEK is intrinsically crystalline, it is made amorphous by a quenching method or the like, and then heated to a temperature higher than the glass transition point, as shown in FIG. During the transformation, the elastic modulus of the resin decreases to a relatively soft elastic modulus suitable for molding (heat compression bonding). Since this elastic modulus lowering temperature region is expanded by the blending of PEI which is a crystallization retarding polymer, if this elastic modulus lowering temperature region is used as a thermocompression bonding temperature region, in an actual mass production line,
A plurality of insulating resin layers 36 can be heated and pressed at once.

Next, an example of a method of manufacturing the coil-containing multilayer resin substrate 29 will be described with reference to FIGS. First,
Using a mixed resin of PEEK: 65 to 35% by weight and PEI: 35 to 65% by weight, a film-like insulating resin layer 36 is formed by an extrusion casting method, a calendar method, or the like. At this time, PEEK in the insulating resin layer 36 is made amorphous by a quenching method or the like. In the mixed resin for forming the insulating resin layer 36,
Needless to say, other resins and additives may be contained to such an extent that the characteristics are not deteriorated.

Thereafter, a conductor foil 45 such as an aluminum foil or a copper foil is adhered to the surface of the insulating resin layer 36 by heat fusion or the like, and then a coil pattern 37 is formed by a subtractive method as follows.

First, an etching resist 51 is screen-printed on the surface of the conductor foil 45 of the insulating resin layer 36 in the shape of the coil pattern 37, and a portion of the conductor foil 45 which becomes the coil pattern 37 is covered with the etching resist 51. I do. Such a method of forming the etching resist 51 is called a printing method.
5 may be coated with a photosensitive etching resist (or a photosensitive dry film resist is adhered) and then exposed and developed to form a pattern of the etching resist 51 (this method is a photographic method). is called).

As described above, the etching resist 51
After the pattern is formed, the process proceeds to the etching step, and the portion of the conductor foil 45 not covered with the etching resist 51 (the portion other than the coil pattern 37) is removed by etching with an etching solution to form the coil pattern 37. I do. After that, the etching resist 51 on the surface of the coil pattern 37 is peeled off with a chemical to expose the surface of the coil pattern 37.

Thereafter, the process proceeds to a flattening press step, in which the insulating resin layer 36 having the coil pattern 37 is accommodated between the parallel press plates 52 and 53, and is placed in a temperature region where the elastic modulus is appropriately reduced (FIG. 5). Press plate 52,
By pressing the insulating resin layer 36 with the coil pattern 37 between the 53 and pressing the coil pattern 37 into the insulating resin layer 36 by the thickness thereof, the surface of the coil pattern 37 and the resin surface of the insulating resin layer 36 are The surface on which the coil pattern 37 of the insulating resin layer 36 is formed is flattened by eliminating the steps. In order to facilitate this flattening press, it is desirable that the thickness of the insulating resin layer 36 be at least twice the thickness of the coil pattern 37 (conductor foil 45).

Thereafter, the process proceeds to a via hole processing step, in which a via hole 39 is formed at the end of the coil pattern 37 in the insulating resin layer 36 by laser processing, punching processing or the like. The via hole 39 is formed by forming the coil pattern 37 and the insulating resin layer 3 from the side on which the coil pattern 37 is formed.
6 may be formed so that the via hole 39 penetrates, but the back side of the coil pattern 37 (the insulating resin layer 36
From the side), only the insulating resin layer 36 may be formed by laser processing or the like so that the via hole 39 penetrates. In this case, it is sufficient that the tip of the via hole 39 reaches the coil pattern 37, and it is not necessary to penetrate the coil pattern 37.

After the processing of the via hole 39, for example, A is formed in the via hole 39 of the insulating resin layer 36 by using a screen printing method.
The via-hole conductor 38 is formed by filling an Ag-based conductor paste such as g-Sn. At this time, the conductive paste is Ag
The conductive paste is not limited to Cu-based and may be Cu-based or Au-based conductor paste.

After sufficiently drying the paste of the via-hole conductor 38, the process proceeds to a laminating / heating / compression bonding step, in which a plurality of insulating resin layers 36 are stacked and accommodated between the parallel press plates 52 and 53, and this is elastically applied. In the temperature range where the rate decreases moderately (Fig. 5
(See FIG. 3), the plurality of insulating resin layers 36 are collectively heated and pressed between the press plates 52 and 53 to be integrated to form a laminated body of the insulating resin layers 36.

Then, in the next step, the surface layer circuit portion 54 formed as described later is superimposed on the surface of the laminated body of the insulating resin layer 36, and is accommodated between the parallel press plates 52, 53.
The surface layer circuit portion 54 is heated and pressed on the surface of the laminated body of the insulating resin layer 36 to be integrated, thereby forming the coil-containing multilayer resin substrate 29.

Thereafter, a solder resist film 56 for protecting the surface wiring pattern 55 is formed on the surface of the coil-embedded multilayer resin substrate 29, and then subjected to a surface treatment step, an outer shape processing step, and an inspection step. Product is completed.

The above-described multilayer resin substrate 29 with a built-in coil.
In the manufacturing method of (1), after the coil pattern 37 is formed (after the flattening press), the via hole 39 is processed and the via hole 39 is filled with the conductive paste, but the conductive foil 45 is formed on the surface of the insulating resin layer 36. Before bonding, the via holes 39 are processed and the via holes 39 are filled with a conductive paste.
May be formed to form the coil pattern 37.

In the above-described manufacturing method, the surface circuit portion 54 is heat-pressed on the surface of the laminate of the insulating resin layers 36 after the plurality of insulating resin layers 36 are laminated and heat-pressed. The plurality of insulating resin layers 36 and the surface layer circuit section 54 may be laminated at a time and then heat-pressed.

Alternatively, a portion corresponding to the surface layer circuit portion 54 is formed on a printed wiring board, and a laminated body of the insulating resin layer 36 (the multilayer resin substrate 29 with a built-in coil) is mounted on the printed wiring board by soldering or the like. You may do it. Further, the method of forming the coil pattern 37 is not limited to the above-described subtractive method, and may use an additive method (also called a plating method).

The surface of the conductor foil 45 is roughened by a chemical treatment such as a blackening treatment or a mechanical treatment, so that the insulating resin layer 3
6 and the coil pattern 37 (the conductor plate 45) may have an increased adhesive strength.

Next, a method of forming the surface layer circuit portion 54 will be described with reference to FIG. The insulating resin layer 57 and the surface wiring pattern 55 of the surface circuit portion 54 may be formed as follows by the same method as the above-described insulating resin layer 36 and coil pattern 37.

First, PEEK: 65 to 35% by weight and PE
I: A film-like insulating resin layer 57 is formed by using a mixed resin of 35 to 65% by weight by an extrusion casting method, a calendar method, or the like. At this time, PEEK in the insulating resin layer 57 is made amorphous by a quenching method or the like. Thereafter, a conductor foil 58 such as an aluminum foil or a copper foil is adhered to the surface of the insulating resin layer 57 by heat fusion or the like, and an etching resist 59 is screen-formed on the surface of the conductor foil 58 in the shape of the surface wiring pattern 55. By printing, a portion of the conductor foil 58 to be the surface wiring pattern 55 is covered with the etching resist 59.

Thereafter, the portion of the conductor foil 58 not covered with the etching resist 59 (the surface wiring pattern 5
5) is removed by etching with an etchant, a surface wiring pattern 55 is formed, and a surface circuit portion 54 is formed. Then, in the next step, a via hole 60 is formed at a predetermined position of the surface layer circuit portion 54 by laser processing, punching processing, or the like. Thereafter, using a screen printing method, the via holes 60 are filled with, for example, an Ag-based conductor paste to form via-hole conductors 61. The via hole conductor 61 plays a role of electrically connecting the surface wiring pattern 55 and the coil pattern 37 in the inner layer.

In the embodiment (1) described above, the choke coil 30, the ignition coil 31, the DC / DC converter coil 3
2, the area of the circuit board 29 can be reduced by the area of the coils 30 to 32 incorporated in the coil-embedded multilayer resin substrate 29, and the demand for miniaturization and high-density mounting can be satisfied. it can. Moreover, each coil 30-3
The number of turns of the coil can be increased by the multilayering of 2, and the relatively large coils 30 to 32 can be built in the multilayer resin substrate 29, and the required coil performance can be easily secured.

Further, in the present embodiment (1), when manufacturing the coil-containing multilayer resin substrate 29, the coil pattern 37 is formed by a printed wiring method which is excellent in mass productivity. It can be formed well. In addition, the via holes 3 formed in the insulating resin layer 36
9 is filled with a conductive paste to form the via-hole conductor 38, so that the via-hole conductor 38 can be efficiently formed by screen printing excellent in mass productivity. Further, since the plurality of insulating resin layers 36 are collectively heated and pressed to be integrated, the number of steps is significantly reduced as compared with a method of sequentially stacking the insulating resin layers 36 one by one. Thus, the coil-containing multilayer resin substrate 29 can be manufactured efficiently.

Further, in the present embodiment (1), before laminating a plurality of insulating resin layers 36, the surface of each insulating resin layer 36 on which the coil pattern 37 is formed is pressed and flattened. Since the step between the resin surface and the surface of the coil pattern 37 is eliminated, when a plurality of insulating resin layers 36 are heat-pressed, the adhesion between the resin surfaces between the layers is improved and the adhesive strength between the two is increased. Thus, delamination can be more reliably prevented.

[Embodiment (2)] Next, FIGS.
A method for manufacturing the resin substrate with a built-in coil in the embodiment (2) of the present invention will be described based on FIG.

First, both surfaces of a conductor plate 65 such as a copper plate or an aluminum plate are roughened by a blackening process. This surface roughening treatment may be performed by chemical treatment or mechanical treatment other than the blackening treatment. Thereafter, an insulating resin layer 66 is attached to the conductor plate 65 by heat fusion or the like. This insulating resin layer 66 is made of 65 to 35% by weight of PEEK and PE as in the first embodiment.
I: molded using a mixed resin of 35 to 65% by weight, and PEEK in the insulating resin layer 66 is made amorphous by a quenching method or the like.

Then, in the next step, via holes 67 are formed at predetermined positions of the insulating resin layer 66 by laser processing or the like so as to penetrate only the insulating resin layer 66. The via hole 67 only needs to reach the conductor plate 65, and the conductor plate 6
It is not necessary to penetrate 5. Thereafter, the via hole 67 is filled with, for example, an Ag-based conductor paste using a screen printing method to form a via-hole conductor 68. The lower end of the via-hole conductor 68 is in close contact with the conductor plate 65, and both are electrically connected.

Thereafter, the conductor plate 65 with the insulating resin layer 66
Is pressed into a coil pattern shape by press working to form a coil pattern 69 with a plurality of insulating resin layers 66. Then, in the next step, the coil patterns 69 with the plurality of insulating resin layers 66 are stacked and accommodated between the parallel press plates 52 and 53, and are accommodated in a temperature region where the elastic modulus is appropriately reduced (see FIG. 5). The laminated coil 70 is manufactured by collectively heating and press-bonding the coil patterns 69 with the plurality of insulating resin layers 66 between the press plates 52 and 53 while heating. At this time, a plurality of laminated coils 70 may be heated and pressed together at a time.
You may make it heat-press-bond individually.

Thereafter, one or more laminated coils 70
Is housed in a molding die 71, an insulating resin is injected into the molding die 71, and the laminated coil 70 is molded to form a coil-embedded resin substrate 72. At this time, as the insulating resin injected into the molding die 71, the same resin as the insulating resin layer 66 may be used, or a resin having another composition may be used.

Then, in the next step, the embodiment (1)
The surface layer circuit portion 73 formed in the same manner as described above is superposed on the surface of the coil-embedded resin substrate 72, and the parallel press plates 52, 53
It is housed in between, and the surface circuit portion 73 is
Heat and pressure bonded to the surface of As a result, FIG.
A resin substrate 72 with a built-in coil having a surface circuit portion 73 as shown in FIG.

A portion corresponding to the surface layer circuit portion 73 may be formed on a printed wiring board, and the resin substrate 72 with a built-in coil may be mounted on the printed wiring board by soldering or the like.

In the embodiment (2) described above, the conductor pattern 65 with the insulating resin layer 66 on which the via hole conductor 68 is formed is punched to form the coil pattern 69, and the coil pattern 69 with the edge resin layer 66 is formed. Since the laminated coil 70 is manufactured by laminating and collectively heating and pressing the laminated coil 70, the laminated coil 70 in which the insulating layer is formed of resin can be efficiently manufactured. Moreover, since the coil pattern 69 is formed by punching, the thickness (conductor cross-sectional area) of the coil pattern 69 can be increased as compared with the case where the coil pattern is formed by a printed wiring method, and the allowable maximum current value can be reduced. There are benefits that can be increased.

Moreover, since the surface of the conductor plate 65 is blackened (roughened), the adhesive strength between the insulating resin layer 66 and the coil pattern 69 (conductor plate 65) can be increased. Can reliably be prevented from peeling off.

In this embodiment (2), a coil pattern 69 with a plurality of insulating resin layers 66 is collectively heated and pressed to form a laminated coil 70, and then the laminated coil 70 is formed.
Is housed in a molding die 71, and an insulating resin is injected into the molding die 71 to mold the laminated coil 70. However, a coil pattern 69 with a plurality of insulating resin layers 66 is provided.
Are collectively heat-pressed, the coil pattern 69 with the insulating resin layer 66 is stacked in a resin molding frame, accommodated, and heat-pressed to form a laminated coil 70 (coil pattern 69).
And a resin molding frame may be thermally fused to form a resin substrate with a built-in coil. In this case, the resin molding frame may be formed of the same resin as the insulating resin layer 66.

The laminated coil 70 may be mounted on another circuit board by soldering or the like. Others
The application of the resin substrate with a built-in coil and the laminated coil manufactured by the method described in each embodiment is not limited, and can be used as a substrate or a coil component of various electric circuits.

[Brief description of the drawings]

FIG. 1 is a plan view of a multilayer resin substrate with a built-in coil showing an embodiment (1) of the present invention.

FIG. 2 is a perspective view of a multilayer resin substrate having a built-in coil.

FIG. 3 is a diagram illustrating the structure of a multilayer resin substrate with a built-in coil.

FIG. 4 is a characteristic diagram illustrating the relationship between the temperature and the elastic modulus of PEEK.

FIG. 5 is a characteristic diagram illustrating the relationship between temperature and elastic modulus of a resin in which PEI is mixed with PEEK.

FIG. 6 is a process chart (1) for explaining a manufacturing process of the multilayer resin substrate with a built-in coil according to the embodiment (1).

FIG. 7 is a process chart (2) for explaining a manufacturing process of the coil-embedded multilayer resin substrate of the embodiment (1).

FIG. 8 is a process chart for explaining a manufacturing process of a surface layer circuit portion of the embodiment (1).

FIG. 9 is a process chart (1) for explaining a manufacturing process of the resin substrate with a built-in coil of the embodiment (2).

FIG. 10 is a process chart (2) for explaining a manufacturing process of the resin substrate with a built-in coil of the embodiment (2).

FIG. 11 is a perspective view of a resin substrate with a built-in coil according to the embodiment (2).

[Explanation of symbols]

29: multilayer resin substrate with built-in coil, 30: choke coil, 31: ignition coil, 32: DC / DC converter coil, 33 to 35: core, 36: insulating resin layer, 37: coil pattern, 38: via hole conductor, 3
9 via hole, 45 conductor foil, 51 etching resist, 52, 53 press plate, 54 surface circuit section, 55
... Surface layer wiring pattern, 56 ... Solder resist film, 57 ...
Insulating resin layer, 58: conductor foil, 59: etching resist, 60: via hole, 61: via hole conductor, 65:
Conductor plate, 66 ... insulating resin layer, 67 ... via hole, 68 ...
Via-hole conductor, 69: coil pattern, 70: laminated coil, 71: molding die, 72: resin substrate with built-in coil, 73
... Surface layer circuit part.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hidesaku Nakazawa 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. (72) Inventor Akira Nidan 1-1 1-1 Showa-cho, Kariya-shi, Aichi Prefecture Inside DENSO Corporation (72) Inventor Shinzuki 5-8 Mitsuyacho, Nagahama-shi, Shiga Prefecture 72) Inventor Koichiro Taniguchi 5-8, Mitsuya-cho, Nagahama-shi, Shiga Prefecture F-term in the Nagahama Plant of Mitsubishi Plastics Co., Ltd. CC39 DD02 DD03 FF18 GG15 HH22 HH25

Claims (10)

[Claims] 1. A plurality of insulating resin layers are alternately laminated and integrated with a coil pattern, and the coil patterns of the respective layers are electrically connected by via-hole conductors formed through the respective insulating resin layers. A multilayer board with a built-in coil. 2. The method according to claim 1, wherein the plurality of insulating resin layers are collectively heat-pressed and integrated.
The multilayer substrate with a built-in coil according to 1. 3. The multilayer board with a built-in coil according to claim 1, wherein the insulating resin layer is formed of a mixed resin of a polyarylketone resin and polyetherimide. 4. A step of forming a plurality of insulating resin layers, a step of forming a coil pattern on the plurality of insulating resin layers by a printed wiring method, and forming a via hole at a predetermined position of the plurality of insulating resin layers. A step of forming a via-hole conductor by filling the via-hole with a conductive paste; and laminating the plurality of insulating resin layers, and heat-pressing them together to integrate the coil patterns of each layer with the via-hole conductor. Manufacturing a multilayer board with a built-in coil that is electrically connected. 5. The method according to claim 1, wherein the plurality of insulating resin layers are formed of a mixed resin of a polyarylketone resin and a polyetherimide, and in the process, the polyarylketone resin is made amorphous. The method for manufacturing a multilayer substrate with a built-in coil according to claim 4, wherein the plurality of insulating resin layers are collectively heat-pressed in a temperature region where the polyaryl ketone resin changes from amorphous to crystalline. 6. Before laminating the plurality of insulating resin layers,
The method for manufacturing a multilayer substrate with a built-in coil according to claim 4 or 5, wherein the surface of each of the insulating resin layers on which the coil pattern is formed is pressed to be flat. 7. A step of forming an insulating resin layer of a conductor plate in which a conductor plate and an insulating resin layer are bonded, forming a via hole in a predetermined position of the insulating resin layer of the conductor plate, and filling the via hole with a conductive paste. Forming a via-hole conductor by punching the conductor resin-plated insulating resin layer into a coil pattern shape to form a coil pattern with a plurality of insulating resin layers; and forming the coil pattern with the plurality of insulating resin layers. Producing a laminated coil in which the coil patterns of the respective layers are electrically connected by the via-hole conductors by laminating and collectively applying heat and pressure to form a laminated coil. . 8. The insulating resin layer is molded from a mixed resin of a polyarylketone resin and a polyetherimide, and in the process, the polyarylketone resin is made amorphous. The method for manufacturing a laminated coil according to claim 7, wherein the coil pattern with the plurality of insulating resin layers is collectively heat-pressed in a temperature range where the aryl ketone resin changes from amorphous to crystalline. 9. The method for manufacturing a laminated coil according to claim 7, wherein the surface of the conductor plate is roughened. 10. A laminated coil manufactured by the method for manufacturing a laminated coil according to claim 7 is housed in a mold, and an insulating resin is injected into the mold to form a coil-embedded substrate. A method for manufacturing a substrate with a built-in coil, which is manufactured.