JP6713187B2 - Multilayer printed wiring board and manufacturing method thereof - Google Patents

Description

The present invention relates to a printed wiring board configured to radiate heat from an electronic component such as a mounted semiconductor element, a mounting structure including the printed wiring board and mounted components, and a method for manufacturing the printed wiring board. ..

In the printed wiring board for heat dissipation, for example, when a thick conductor is required for a power supply circuit or the like, a method using a thick copper type core substrate is known as disclosed in Patent Documents 1 and 2. There is. Further, Patent Document 3 discloses a method in which a wire is welded to a copper foil so that the same effect as that of thick copper is given only to a necessary portion.

However, according to the methods of Patent Documents 1 and 2, since the copper foil surface to be used becomes extremely thick, it is difficult to form a fine wiring pattern by the etching process due to the influence of the bottom of the etching. Further, there is a problem that the circuit width accuracy of the heat dissipation thick wiring pattern portion is deteriorated due to the bottoming of the etching.
Patent Document 3 proposes a technique in which a wire having a thickness of 0.3 mm to 0.4 mm is welded to a copper foil to bring about the same effect as thick copper only in a necessary portion. However, in the method of Patent Document 3, it is necessary to bond the copper foil and the wire with high precision by using a special device.

Patent Document 4 discloses a heat dissipation printed wiring board in which a small metal piece (heat dissipation block) of copper or the like is housed in a through hole formed in a core substrate. In such a printed wiring board, it is not necessary to use thick copper as the core substrate, and the above-mentioned problems are unlikely to occur. However, after the insulating resin layer is laminated on the core substrate, heat is transferred to the heat dissipation block via the via hole, so that there is a problem that the heat transfer amount is limited to the cross-sectional area of the via hole.

In Patent Document 5, when a via conductor (small metal piece or the like) is fitted into the opening, the projection of the via conductor is fitted and fitted in the groove of the opening. Since this via conductor has a small shape of about 0.2 to 0.5 mm on one side of the area of the opening, a gap is created, and an adhesive resin or the like for filling this gap is filled. Further, a technique is disclosed in which the via conductor and the ground pattern are integrated so that the via conductor does not fall out of the opening.
However, in Patent Document 5, since the via conductor has a protrusion, it is difficult to form the via conductor, and there is a problem that the cost is high and the yield is low. Further, when the via conductor is fitted into the opening of the substrate, since the projection of the via conductor is coupled and fitted into the groove of the opening, it is necessary to align the via conductor with high accuracy. Requires a considerable amount of force, it is difficult to mate without special equipment. Also, this via conductor cannot fit into an opening of 0.2 mm or less. In addition, the via conductor and the ground pattern are integrated to prevent the via conductor from falling out of the opening even though the adhesive resin or the like for filling the gap between the via conductor and the opening is filled. Since it is necessary, there is a risk that the via conductor will fall out of the opening during the transportation and work from the fitting of the via conductor to the integration of the via conductor and the ground pattern, resulting in extremely low productivity. ..

Further, Patent Document 5 discloses a structure in which a via conductor is built in and one side surface is plated to be integrated, but since only one side is plated, circuits cannot be formed on both sides. There are design restrictions such as.

JP-A-8-293659 JP, 2002-076751, A Japanese Patent Publication No. 2008-529263 JP, 2013-135168, A JP, 2010-258260, A

A main object of the present invention is to provide a printed wiring board which has excellent heat dissipation performance for dissipating heat from mounted components and which can form a fine circuit on the surface layer of the board.
Another object of the present invention is to provide a method of manufacturing a printed wiring board which has excellent heat dissipation and can efficiently manufacture a printed wiring board capable of forming a fine circuit on the surface layer of a substrate.

As a result of intensive studies to solve the above problems, the present inventor has found a solving means having the following configuration, and completed the present invention.
(1) A core substrate in which a wiring pattern is formed on at least one surface of an insulating plate, an insulating resin layer laminated on the surface of the core substrate, and a through hole penetrating the core substrate and the insulating resin layer. A printed wiring board, comprising: a portion; and a metal piece housed in the housing portion.
(2) The printed wiring board according to (1), wherein the metal piece is fixed by filling an insulating metal piece fixing resin in a gap portion between the inner peripheral surface of the accommodating portion and the metal piece.
(3) The printed wiring board according to (1) or (2), wherein the metal piece is a copper piece.
(4) The accommodating portion is an inverted frustum shape whose size decreases from one surface to the other surface of the printed wiring board, or a columnar through hole having a constant size, (1) to (3) The printed wiring board according to any one of 1.
(5) The printed wiring board according to any one of (1) to (4), wherein the surface of the metal piece is substantially flush with the surface of the insulating resin layer.
(6) The printed wiring board according to any one of (1) to (5), further including a wiring conductor layer formed on the surface of the metal piece.
(7) A mounting structure in which a component is mounted at a position where the metal piece is accommodated on at least one surface of the printed wiring board according to any one of (1) to (6).
(8) The component according to (7), wherein the component is mounted face down or face up on a printed wiring board, and a lower part of the component is adhered to a small metal piece with a heat conductive resin or a low melting point metal. Structure.
(9) The mounting structure according to claim 8, wherein the lower part of the component is brought into close contact with the metal piece via a wiring conductor layer formed on the surface of the metal piece.
(10) A step of forming a wiring pattern on at least one surface of an insulating plate to obtain a core substrate, a step of laminating an insulating resin layer on the surface of the core substrate, and a penetration for penetrating the core substrate and the insulating resin layer. A method of manufacturing a printed wiring board, comprising: a step of forming a housing portion that is a hole; and a step of housing a small metal piece in the housing portion.
(11) The method for manufacturing a printed wiring board according to (10), including a step of forming a wiring conductor layer on the surface of the metal piece after the step of containing the metal piece in the containing portion.
(12) The method for manufacturing a printed wiring board according to (10) or (11), further including a step of forming a via hole in the insulating plate before the step of obtaining the core substrate.
(13) The method for manufacturing a printed wiring board according to any one of (10) to (12), wherein the step of forming the accommodation portion is performed by laser processing or die processing.
(14) After the step of accommodating the metal piece in the accommodating portion, the method further includes the step of filling an insulating metal piece fixing resin in a gap between the accommodating portion and the metal piece and curing the resin. The method for manufacturing a printed wiring board according to any one of (13).

According to the printed wiring board of the present invention, the thickness of the metal piece housed in the housing portion and the substrate thickness (total thickness of the core substrate and the insulating resin layer) can be adjusted to be the same. It is easy to form a fine circuit because there is no step.
Further, since the small metal piece housed in the housing portion and the mounted component come into contact with each other without the via hole, high heat dissipation performance can be stably obtained. Further, since no small metal piece is press-fitted into the accommodating portion, there is an effect that a general-purpose component mounter can be used without requiring a special device for incorporation.

According to the printed wiring board manufacturing method of the present invention, it is possible to efficiently manufacture a printed wiring board having excellent heat dissipation performance.

(A) is a plan view showing one embodiment of a printed wiring board according to the present invention, and (b) is a sectional view taken along the line A-A' of (a). It is a side sectional view showing an embodiment in a manufacturing method of a printed wired board concerning the present invention. It is a side sectional view showing an embodiment in a manufacturing method of a printed wired board concerning the present invention. It is a side sectional view showing an embodiment in a manufacturing method of a printed wired board concerning the present invention. It is a side view which shows one Embodiment of the structure body in which the components were mounted in the printed wiring board which concerns on this invention. It is a side view which shows another embodiment of the structure in which the components were mounted in the printed wiring board which concerns on this invention. It is a sectional side view which shows another form of the printed wiring board which concerns on this invention.

The printed wiring board of the present invention will be described with reference to FIG. FIG. 1(a) is a plan view showing an embodiment of a printed wiring board according to the present invention, and FIG. 1(b) is a sectional view taken along the line AA' of FIG. 1(a).
As shown in FIG. 1A, the printed wiring board of the present invention includes a housing portion 11 for housing the small metal piece 40 and a wiring board portion 12. More specifically, as shown in FIG. 1( b ), the printed wiring board of the present invention is laminated on the core substrate 2 on which the wiring pattern 4 is formed on the surface of the insulating plate 1 and on the surface of the core substrate 2. An insulating resin layer 21a, a metal piece 40 housed in the housing portion 11 formed by penetrating the core substrate 2 and the insulating resin layer 21a, and a wiring conductor layer 22 formed on the surface of the metal piece 40 are provided. .. Further, via holes 3 are formed in the insulating plate 1 to electrically connect the upper and lower surfaces of the core substrate 2.

The insulating plate 1 is not particularly limited as long as it is made of an insulating material. Examples of such insulating materials include organic resins such as epoxy resin, bismaleimide-triazine resin, polyimide resin, and polyphenylene ether (PPE) resin. You may use these organic resins in mixture of 2 or more types. When an organic resin is used as the insulating plate 1, it is preferable to use a reinforcing material mixed with the organic resin. Examples of the reinforcing material include glass fiber, glass non-woven fabric, aramid non-woven fabric, aramid fiber, and polyester fiber. Two or more kinds of these reinforcing materials may be used in combination. The insulating plate 1 is preferably formed of a glass material-containing organic resin such as glass fiber or glass non-woven fabric. Furthermore, the insulating plate 1 may contain an inorganic filler such as silica, barium sulfate, talc, clay, glass, calcium carbonate, or titanium oxide. The thickness of the insulating plate 1 is not particularly limited, but is preferably 0.02 to 10 mm.

Like the printed wiring board shown in FIG. 1, the wiring patterns 4 are preferably formed on both surfaces of the insulating plate 1. That is, the wiring pattern 4 exists on the upper and lower surfaces of the core substrate 2. In this case, via holes 3 are formed in the insulating plate 1 in order to electrically connect the upper and lower surfaces of the core substrate 2.

An insulating resin layer 21 a is laminated on the surface of the core substrate 2. Examples of the resin forming the insulating resin layer 21a include epoxy resin, bismaleimide-triazine resin, polyimide resin, polyphenylene ether (PPE) resin, phenol resin, polytetrafluoroethylene (PTFE) resin, silicon resin, polybutadiene resin, Examples thereof include polyester resin, melamine resin, urea resin, polyphenylene sulfide (PPS) resin, and polyphenylene oxide (PPO) resin. Two or more kinds of these resins may be mixed. The resin forming the insulating resin layer 21a may include the above-mentioned reinforcing material, inorganic filler, and organic filler made of phenol resin or methacrylic resin.

The wiring conductor layers 22 formed on both surfaces of the small metal piece 40 are formed by etching or the like. Details of the method for forming the wiring conductor layer 22 will be described later.

In the printed wiring board shown in FIG. 1, the insulating resin layer 21a and the wiring conductor layer 22 are laminated one layer on each of the upper and lower surfaces of the printed wiring board, but not limited to one layer. For example, the insulating resin layers 21a and the wiring conductor layers 22 may be alternately laminated to form a multilayer buildup layer. In this case, the via hole 23 is formed in the insulating resin layer 21a.

In the printed wiring board of the present invention, the small metal piece 40 is housed in the housing portion 11 formed in the insulating plate 1. Examples of the metal that constitutes the metal piece 40 include copper, gold, iron, and aluminum. Among these metals, copper is preferable. When the metal piece 40 is a copper piece, for example, it is obtained by the following method.
(I) A copper plate or copper foil is processed into copper pieces by etching.
(II) A copper plate, a copper foil or a copper wire rod is punched with a die to be processed into a copper piece.
(III) A copper plate or copper foil is cut into pieces by cutting with dicing.
Since the metal piece 40 is built in the printed wiring board, the total thickness of the core substrate 2 and the insulating resin layer 21a is preferably about ±25 μm.

The shape of the metal piece 40 in the present embodiment is a rectangular parallelepiped. The housing portion 11 that houses the small metal piece 40 is a through hole that penetrates the printed wiring board and has a rectangular parallelepiped shape similar to the small metal piece 40.

The size of the metal piece 40 is appropriately set according to the thickness of the insulating plate 1. For example, the long side of the lower surface of the small metal piece 40 is about 0.1 to 50 mm, and the height (thickness) from the upper surface to the lower surface of the small metal piece 40 is about 0.02 to 10 mm.

An insulating metal piece fixing resin 13 is filled in a gap between the inner peripheral surface of the housing portion 11 and the metal piece 40, so that the metal piece 40 is fixed in the housing portion 11.

Examples of the metal piece fixing resin 13 include epoxy resin, acrylic resin, polyimide resin, and polyphenylene ether (PPE) resin. Among these, an epoxy resin or a mixed resin of an epoxy resin and another resin is preferable. The metal piece fixing resin 13 may further contain a filler such as silica, barium sulfate, talc, clay, glass, calcium carbonate, titanium oxide and the like.

Next, a method for manufacturing a printed wiring board according to the present invention will be described. The method for manufacturing a printed wiring board according to the present invention includes the following steps (i) to (vi).
(I) A core board in which a wiring pattern is formed on both surfaces of an insulating plate to obtain a core board, insulating resin layers are laminated on both surfaces of the core board, and a thin copper foil is further laminated on the surface of the insulating resin layer. A step of obtaining a laminate with an insulating resin layer (hereinafter referred to as a laminate).
(Ii) The thin copper foils immediately above and below the accommodating portion of the laminated body are removed by etching or the like to form an accommodating portion penetrating the laminated body, and polyethylene terephthalate ( A step of attaching a PET film and accommodating the metal pieces from above.
(Iii) A step of filling the gap between the inner peripheral surface of the accommodating portion and the metal piece with the metal piece fixing resin.
(Iv) A step of curing the metal piece fixing resin, peeling off the PET film, and polishing so that the surface of the printed wiring board and the surface of the metal piece are substantially flush with each other.
(V) A step of forming a via hole in a portion of the printed wiring board that does not contain a small metal piece.
(Vi) A step of plating both surfaces of the printed wiring board, adjusting the thickness of the conductor by etching or the like, forming a wiring conductor layer, printing a solder resist, and performing gold plating or the like.

A method for manufacturing a printed wiring board according to the present invention will be described with reference to FIGS. First, as shown in FIG. 2A, a double-sided copper-clad substrate 2b having thin copper foils 2a formed on both surfaces of an insulating plate 1 is prepared. The thin copper foil 2a preferably has a thickness of about 1 to 12 μm. The insulating plate 1 is as described above, and a description thereof will be omitted.

As shown in FIG. 2B, a via hole prepared hole 3a is formed at a predetermined position of the double-sided copper clad board 2b. The via hole lower hole 3a is a hole for forming the via hole 3 that electrically connects the upper and lower surfaces of the insulating plate 1. The via hole pilot hole 3a is formed by, for example, laser processing. Examples of the laser light include CO ₂ laser and UV-YAG laser. The thin copper foil 2a immediately above the via hole pilot hole 3a may be opened at the same time when the via hole pilot hole 3a is formed.

When the via hole prepared hole 3a is formed by laser processing, a thin resin film may remain on the bottom of the via hole prepared hole 3a. In this case, desmear processing is performed. In the desmear treatment, the resin is swollen with a strong alkali, and then the resin is decomposed and removed using an oxidizing agent (eg, chromic acid, permanganate aqueous solution, etc.). Alternatively, the resin film may be removed by wet blast treatment with an abrasive or plasma treatment. Further, the inner wall surface of the via hole pilot hole 3a may be roughened. Examples of the surface roughening treatment include a wet process using an oxidizing agent (eg, chromic acid, an aqueous solution of permanganate, etc.), a dry process such as plasma treatment or ashing treatment, and the like.

Next, as shown in FIG. 2C, the inner wall surface of the via hole pilot hole 3a and the surface of the insulating plate 1 are plated with copper to form the conductor 2c and the via hole 3. The copper plating may be electroless copper plating or electrolytic copper plating. Electrolytic copper plating is preferable for thickening the plating, and for example, copper plating having a thickness of about 1 to 30 μm is formed. Further, not only the inner wall surface of the via hole pilot hole 3a, but also the via hole pilot hole 3a may be filled with copper by filled plating to form the via hole 3.

Next, as shown in FIG. 2D, the wiring pattern 4 is formed on the surface of the insulating plate 1. A photosensitive resist (for example, a dry film etching resist) is attached by roll lamination, and exposed and developed to expose a portion other than the circuit pattern. The exposed copper is removed by etching. Examples of the etching solution include ferric chloride aqueous solution. The etching resist of the dry film is peeled off to form the wiring pattern 4. In this way, the core substrate 2 having the wiring pattern 4 formed on the surface of the insulating plate 1 is obtained.

Next, as shown in FIGS. 2E and 2F, the prepreg 21 and the thin copper foil 22a are laminated on the surface of the core substrate 2, and thermocompression bonding is performed by a lamination press to cure the prepreg 21 and the insulating resin layer 21a. (Cured resin layer) is formed. In addition, as the prepreg 21, the resin (the reinforcing material and the filling material as necessary) described in the above-mentioned insulating resin layer 21a is used.
The laminated body 20 (hereinafter, laminated body 20) of the core substrate 2 and the insulating resin layer 21a thus obtained is not limited to the multilayer buildup substrate, and a double-sided substrate or a multilayer substrate may be used. ..

Next, as shown in FIGS. 3G and 3H, the accommodating portion 11 for accommodating the small metal piece 40 is formed in the laminated body 20.
First, as shown in FIG. 3(g), a photosensitive resist such as a dry film is used in a portion of the copper clad substrate 20 where a metal piece is to be incorporated, and the copper foil of the laminate 20 is formed by a known etching method. The copper foil opening 26 is created by removing 22a. The copper foil opening 26 is made slightly larger than the size of the small metal piece 40, preferably about 25 μm on one side.

Next, as shown in FIG. 3(h), a laser process such as a CO ₂ laser or a UV-YAG laser or a metal mold is used at a portion where the insulating resin layer 21a is exposed by the copper foil opening 26. The accommodating portion 11 that penetrates the stacked body 20 is formed by punching or the like.

Next, as shown in FIGS. 3( i) and 3 (j ), PET having an adhesive layer is provided on the lower surface of the laminate 20 in which the accommodating portion 11 is formed (that is, the side opposite to where the metal piece 40 is mounted). After sticking the film 50, the small metal piece 40 is housed in the housing portion 11 using a mounting machine such as a mounter. The height of the metal piece 40 may be the same as the surface layer of the laminate 20 or may be protruding.
At this time, by sticking the PET film 50 to the lower surface of the laminated body 20, it is possible to prevent the small metal piece 40 from dropping from the inside of the housing portion 11. Instead of the PET film 50, a repeatedly usable MagiCarrier (manufactured by Kyosha Co., Ltd.) or PROLEADER (manufactured by Fuji Film Co., Ltd.) may be used.

Next, as shown in FIG. 3(k), the insulating metal piece fixing resin 13 is filled in the gap between the peripheral portion of the metal piece 40 housed in the housing portion 11 and the inner peripheral surface of the housing portion 11, The metal piece fixing resin 13 is cured.

As a method of filling the small metal piece fixing resin 13, for example, a method such as screen printing, spraying, or dispenser is used. After filling, if it is a thermosetting resin, it is cured in a high temperature tank, and if it is an ultraviolet curing resin, it is cured by irradiation with ultraviolet rays.

After the metal piece fixing resin 13 is cured, the PET film 50 is peeled from the laminate 20 (printed wiring board) in which the metal piece 40 is housed in the housing 11, as shown in FIG.

Next, as shown in FIG. 4(m), the metal piece fixing resin 13 adhered to an extra portion and hardened and the metal piece 40 protruding from the printed wiring board are subjected to physical polishing such as buffing or chemical polishing such as etching. And make it flush with the surface.

Next, as shown in FIG. 4(n), a via hole pilot hole 23a for interlayer connection of the inner layer circuit is formed in the insulating resin layer 21a at a position of the laminated body 20 in which the metal piece 40 is not incorporated. The via-hole pilot hole 23a is formed by laser processing or the like, and desmearing or roughening is performed if necessary.

Next, as shown in FIG. 4( o ), copper plating 60 is formed on the surface layer of the printed wiring board to fill the via-hole pilot holes 23 a with copper plating 60, and copper is also applied on the metal pieces 40 and the metal piece fixing resin 13. The plating 60 is formed to obtain the via hole 23 (FIG. 4(p)).

After the copper plating treatment, a chemical roughening treatment such as a soft etching treatment with a mixed solution of sulfuric acid and hydrogen peroxide or a mechanical roughening treatment such as buffing is performed to perform treatment up to an arbitrary conductor thickness.
Then, using a known method, a photosensitive resist, for example, a dry film etching resist is attached by roll lamination, exposed and developed to expose a portion other than the circuit pattern, and the exposed portion of the copper plating 60 is etched. Remove. An aqueous ferric chloride solution or the like can be used as this etching solution.
Then, by removing the etching resist of the dry film, the wiring conductor layer 22 can be formed on the surfaces of the insulating resin layer 21a and the metal piece 40 as shown in FIG. 4(p). The wiring conductor layer 22 can be formed by the same method as that of the wiring pattern 4 described above.

The size of the wiring conductor layer 22 formed on the surface of the small metal piece 40 is larger by 15 to 25 μm on each side than the thin copper foil opening 26 formed in FIG. This is because when the wiring conductor layer 22 is smaller than the thin copper foil opening 26, the etching solution penetrates into the metal piece fixing resin 13 and the metal piece 40 is prevented from being etched.

Finally, as shown in FIG. 4(q), the solder resist 30 is formed at a predetermined position on the surface of the insulating resin layer 21a. As a method for forming the solder resist 30, first, a spray coating, a roll coating, a curtain coating, a screen method or the like is used, and a photosensitive liquid solder resist is applied to a thickness of about 20 μm and dried, or a photosensitive dry film solder resist is used. Stick with a roll laminate. After that, exposure and development are performed to open the pad portion and heat curing.

Before forming the solder resist 30, the formation surface may be subjected to a copper roughening treatment such as a CZ treatment. Electroless nickel plating with a thickness of 3 μm or more is formed in the opening of the solder resist 30, and electroless gold plating is 0.03 μm or more (preferably 0.06 μm or more, 0.3 μm for wire bonding applications). The above thickness) may be formed. Such a plating layer 31 is formed on the wiring conductor layer 22 and the via hole 23 as shown in FIG. 4(q), and a solder precoat may be further applied on the wiring layer. It may be formed by electrolytic plating instead of electroless plating. Instead of plating, a water-soluble anticorrosive organic coating (for example, Tough Ace manufactured by Shikoku Chemicals Co., Ltd.) may be formed. The printed wiring board of the present invention is obtained by performing the outer shape processing.

In the method for manufacturing a printed wiring board shown in FIGS. 2(a) to 4(q), the insulating resin layer 21a and the wiring conductor layer 22 are laminated one layer each on the upper and lower surfaces of the printed wiring board. The method for manufacturing the printed wiring board of the invention is not limited to one layer. For example, even when the insulating resin layers 21a and the wiring conductor layers 22 are alternately laminated to form a multi-layer build-up layer, as in the steps of FIG. 2F to FIG. The part 11 can be formed and the metal piece 40 can be installed.

Components such as semiconductor elements are mounted on the printed wiring board of the present invention and processed into a mounting structure. For example, FIG. 5 shows a mounting structure in which a component 70 is wire-bonded (face-up) mounted to a printed wiring board according to the present invention, and FIG. 6 shows a printed wiring board according to the present invention in which a component 71 is flipped. A chip (face down) mounted mounting structure is shown.
The components 70 and 71 and the wiring conductor layer 22 on the upper surface of the small metal piece 40 are connected via a heat transfer material such as a heat conductive resin 80, and in FIG. 6, the solder balls 81 of the component 71 are connected to the via holes 23.
The heat transfer material is not limited to the heat conductive resin, but may be a low melting point metal such as solder. For example, it is a metal having a composition such as Sn3.0Ag0.5Cu.
Since the small metal piece 40 and the surface-mounted components 70, 71 are in contact with each other without a via hole as in the conventional case, the heat dissipation from the mounted component is improved. In the above embodiment, the metal piece 40 and the surface-mounted components 70, 71 are in close contact with each other via the wiring conductor layer 22, but the metal piece 40 exposed on the surface without the wiring conductor layer 22. The components 70 and 71 may be directly adhered to each other.

In the above embodiments, the case where the metal piece and the accommodating portion are both in the shape of a rectangular parallelepiped is described. However, the accommodating portion may be, for example, an inverted truncated cone, an inverted elliptical truncated cone, or an inverted polygonal truncated cone. It may be trapezoidal. Examples of the inverted polygonal truncated pyramid include an inverted quadrangular truncated pyramid, an inverted triangular truncated pyramid, an inverted pentagonal truncated pyramid, an inverted hexagonal truncated pyramid, an inverted octagonal truncated pyramid, and the like. To be

Further, the small metal piece may have, for example, a frustum shape (frustroconical shape, elliptical frustum shape, polygonal frustum shape, or the like), a columnar shape (cylindrical shape, elliptic shape, polygonal shape, or the like). Examples of the polygonal truncated pyramid include a triangular truncated pyramid, a pentagonal truncated pyramid, a hexagonal truncated pyramid, a heptagonal truncated pyramid, and an octagonal truncated pyramid. In addition to the quadrangular prism, examples of the polygonal prism include a triangular prism, a pentagonal prism, a hexagonal prism, a heptagonal prism, and an octagonal prism.
It is preferable that the metal piece and the accommodating portion have the same number of angles (shape) such as a truncated pyramid shape and an inverted truncated pyramid shape.

FIG. 7 shows an example in which the accommodating portion 11′ has an inverted truncated cone shape. The metal piece 40' housed in the housing portion 11' is formed of a rectangular parallelepiped, and the lower end portion is held by the lower edge portion of the housing portion 11'. Others are the same as those of the wiring board shown in FIGS. 1 to 6, and therefore, the same reference numerals are given and the description thereof will be omitted.
When the accommodating part 11' is formed into an inverted frustum shape in this manner, since the upper part of the accommodating part 11' is wide, it is easy to accommodate the small metal piece 40', and the metal small piece is formed at the lower edge of the accommodating part 11'. 40' can be held stably.

DESCRIPTION OF SYMBOLS 1 Insulation plate 2 Core board 2a Thin copper foil 2b Double-sided copper clad board 2c Conductor 3 Via hole 3a Via hole pilot hole 4 Wiring pattern 11, 11' Storage part 12 Wiring board part 13 Small metal piece fixing resin 20 Laminated body 21 Prepreg 21a Insulating resin layer 22 wiring conductor layer 22a thin copper foil 23 via hole 23a via hole prepared hole 26 thin copper foil opening 30 solder resist 31 plating layer 40, 40' metal small piece 50 PET film 60 copper plating 70,71 parts 80 thermal conductive resin 81 solder ball

Claims (11)

A core substrate having a wiring pattern formed on at least one surface of the insulating plate;
A multilayer build-up layer that is laminated on the surface of the core substrate and in which insulating resin layers and wiring conductor layers are alternately laminated,
An accommodating portion that is a through hole that penetrates the core substrate and the buildup layer,
A small piece of metal housed in this housing,
Equipped with
The insulating resin layer includes a thin copper foil having a copper foil opening, the diameter of the copper foil opening is larger than the diameter of the accommodation portion,
A metal piece is fixed by filling an insulating metal piece fixing resin in a portion from the gap between the inner peripheral surface of the accommodating portion and the metal piece to the surface of the insulating resin layer, and the metal piece is fixed to the surface of the metal piece and the metal piece. A multilayer printed wiring board, further comprising a wiring conductor layer made of copper plating formed on the surface of the fixing resin and copper plating formed on the thin copper foil on the surface of the insulating resin layer. The metal piece is frustum-shaped, and the accommodating portion is an inverted frustum-shaped through hole whose size decreases from one surface to the other surface of the multilayer printed wiring board. The multilayer printed wiring board according to claim 1, wherein a frustum-shaped metal piece is housed. The metal piece has a polygonal truncated cone shape, a truncated cone shape, or an elliptical truncated cone shape, and the accommodation portion is an inverted polygonal truncated cone shape, an inverted truncated cone shape, or an inverted elliptical truncated cone shape through hole. The multilayer printed wiring board according to. The multilayer printed wiring board according to claim 1, wherein the metal piece is a copper piece. The multilayer printed wiring board according to claim 1, wherein the surface of the metal piece is substantially flush with the surface of the buildup layer. A mounting structure, in which a component is directly mounted at a position where the metal piece is accommodated on at least one surface of the multilayer printed wiring board according to claim 1. 7. The mounting structure according to claim 6, wherein the component is mounted face down or face up on a printed wiring board, and a lower portion of the component is adhered to a metal piece with a heat conductive resin or a low melting point metal. The mounting structure according to claim 7, wherein the lower part of the component is brought into close contact with the metal piece through a wiring conductor layer formed on the surface of the metal piece. Forming a wiring pattern on at least one surface of the insulating plate to obtain a core substrate;
An insulating resin layer containing a thin copper foil and a wiring conductor layer are alternately laminated on the surface of the core substrate, and a multilayer build-up layer including a copper foil opening obtained by partially removing the thin copper foil is formed. The process of
The copper foil opening, a step of the core through the board and the buildup layer, forming the copper foil opening diameter size than smaller through hole of the housing portion,
A step of accommodating a metal piece whose height is larger than the thickness of the accommodating part in the accommodating part;
A step of filling and curing an insulating metal piece fixing resin from the gap between the accommodating portion and the metal piece to the surface of the insulating resin layer ,
After curing the metal piece fixing resin, a step of polishing so that the surface of the metal piece protruding from the surface of the printed wiring board and the surface of the cured metal piece fixing resin are substantially flush with each other,
Copper plating formed on the surface of the metal piece and the surface of the metal piece fixing resin, and a step of forming a wiring conductor layer made of copper plating formed on a thin copper foil on the surface of the insulating resin layer,
A method for producing a multilayer printed wiring board, comprising: The method for manufacturing a multilayer printed wiring board according to claim 9, further comprising the step of forming via holes in an insulating plate to electrically connect the upper and lower surfaces of the core substrate before the step of obtaining the core substrate. The method for manufacturing a multilayer printed wiring board according to claim 9, wherein the step of forming the housing portion is performed by laser processing or die processing.

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