JP2002359319A - Wiring board incorporating electric element and method of manufacturing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board incorporating an electric element of a structure that the electrical connection of thermal electrodes on the electric element with wiring circuit layers and via hole conductors in the wiring board can be modified without processing via holes, and to provide a method of manufacturing the wiring board incorporating the electric element. SOLUTION: A wiring board incorporating an electric element is constituted in a structure that the insulating layer 5 of at least one layer of a plurality of insulating layers 1, 3 and 5 contains conductive grains 19 and the electric element 17 is electrically connected with via hole conductors 11 and/or wiring circuit layers 8, 9, 13 and 15 on the side of the wiring board A via condensed parts 21 using the grains 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a multilayer wiring board and a package for accommodating a semiconductor element, and more particularly to a wiring board with a built-in electric element in which an electric element is built in an insulating substrate and a method for manufacturing the same. is there.

[0002]

2. Description of the Related Art In recent years, with the demand for higher performance and smaller size of electronic equipment, there has been a demand for a wiring board which is compatible with higher density and higher functionality of circuit components. As such a wiring board, a plurality of wiring circuit layers and these wiring circuit layers are formed on the surface and / or inside of an insulating substrate formed by laminating at least a plurality of insulating layers containing an organic resin. It is known that a via hole conductor connected in the thickness direction is formed, and further, an electric element such as a multilayer capacitor or a semiconductor element is connected to the inside of the wiring board by a bonding agent such as solder or a conductive adhesive. I have.

[0003]

However, in the above-described wiring board with a built-in electric element, electric elements such as a multilayer capacitor and a semiconductor element built in the wiring board are connected by a conductive adhesive and heated and pressed. Therefore, when the distance between the terminal electrodes of the built-in electric element is reduced, the conductive adhesive applied to the terminal electrodes is deformed and spreads, bridging between adjacent terminal electrodes, and the wiring circuit layer is short-circuited. There was a problem of doing.

[0004] Further, to reduce the thickness of the wiring circuit layer and the diameter of the via hole by reducing the size and density of the wiring board, and to reduce the terminal electrodes and the pitch of the terminal electrodes due to the reduction in the size of electric elements such as multilayer capacitors. In addition, the connection between the terminal electrode and the via hole conductor or the wiring circuit layer formed on the wiring board becomes difficult due to the reduction in the area of the connection part or the displacement of the connection position, and the electrical resistance of the wiring board can be increased and impedance matching can be performed. There was a problem that it disappeared.

In addition, the processing time is increased due to the reduction in the diameter of via holes formed in the wiring board and the increase in the number of via holes,
There is a problem in that the manufacturing cost is increased due to an increase in the number of steps for removing processing waste generated during via hole processing.

Accordingly, the present invention provides a wiring board with a built-in electric element and a method of manufacturing the same, which can improve the electrical connection between the terminal electrode of the electric element and the wiring circuit layer or the via hole conductor of the wiring board without processing the via hole. With the goal.

[0007]

The inventor of the present invention has studied the above-mentioned problems, and as a result, when forming a wiring board with a built-in electric element, the inside of the wiring board has insulation on the side to which the electric element is connected. As a layer, conducting heating and pressing using a conductive particle-dispersed insulating sheet made of conductive particles and a thermosetting resin,
By embedding the protruding terminal electrode of the electric element in this conductive particle dispersion sheet and forming a condensed part by conductive particles in the area of the terminal electrode, it is electrically stable with the wiring circuit layer and via hole conductor inside the wiring board It has been found that a wiring board with a built-in electric element can be provided which can be connected to a device, and the present invention has been accomplished.

That is, the wiring board with a built-in electric element of the present invention comprises:
An insulating substrate formed by laminating an insulating layer containing at least an organic resin, a plurality of wiring circuit layers formed on the surface and / or inside of the insulating substrate, and at least a metal component filled in the insulating substrate. In a wiring board with a built-in electrical element having a built-in electrical element having a terminal electrode inside a wiring board having a via hole conductor, at least one of the plurality of insulating layers includes conductive particles. Wherein the terminal electrode of the electric element is electrically connected to a via-hole conductor and / or a wiring circuit layer on the wiring board side via a condensing portion of the conductive particles.

According to such a configuration, the wiring circuit layer or the via-hole conductor of the wiring board and the terminal electrode of the electric element are connected to each other.
Since the connection is made without using a bonding agent such as solder or a conductive adhesive, the deformation and spread of the bonding agent during heating and pressing are suppressed, and the electric element and the wiring circuit layer or the via-hole conductor inside the wiring board are connected. Connectivity can be improved.

[0010] Further, since a condensed portion containing conductive particles can be reliably formed at the position of the terminal electrode, connection is made without displacing the position of the terminal electrode of the electric element with the wiring circuit layer or via hole conductor inside the wiring board. As a result, an increase in the electrical resistance of the wiring board can be suppressed, and the impedance matching can be improved.

In the above-described wiring board with a built-in electric element, the proportion of the conductive particles in the insulating layer is preferably 5 to 30% by volume. By setting the content of the conductive particles in the insulating layer in this range, it is possible to prevent a conduction failure due to a shortage of the conductive particles and a short circuit due to an excessive amount of the conductive particles, and form a connection portion having a low electric resistance. it can.

In the wiring board with a built-in electric element, the conductive particles are desirably made of one kind selected from Ag, Cu, Ni and Au, or an alloy thereof. By using a low-resistance metal as the conductive particles constituting the condensing portion, the transmission speed in the wiring board can be increased.

In the above-mentioned wiring board with a built-in electric element, the conductive particles are preferably substantially spherical particles. By making the shape of the conductive particles constituting the condensing portion substantially spherical as described above, the thermosetting resin contained in the insulating layer at the contact points between the conductive particles can be eliminated, and the electrical connectivity can be improved. it can.

In the wiring board with a built-in electric element, the average particle size of the conductive particles is preferably 10 μm or less. By using the conductive particles having a small average particle size in this manner, the uniform dispersibility of the conductive particles inside the insulating layer can be increased, and the difference in electric resistance between the condensing portion and the other portions can be increased. Connectivity can be improved.

In the above-mentioned wiring board with a built-in electric element, it is desirable that the electric element has a protruding terminal electrode on at least the main surface side of the electric element. Since the terminal electrodes are formed in a convex shape on the main surface side of the electric element, the protruding terminal electrodes forcibly push the conductive particles formed on the insulating layer, thereby reducing the density of the condensed portion. And the electrical connection between the terminal electrode formed on the electric element and the wiring circuit layer or via-hole conductor can be improved.

In the above wiring board with a built-in electric element, the thickness of the electric element is preferably 50 to 95% of the thickness of the insulating layer. By making the terminal electrode higher from the main surface of the electric element in this way, the density of the condensed portion of the conductive particles can be further increased, the electric resistance of the condensed portion is reduced, and the electric connection between the electric element and the wiring board is reduced. Performance can be improved and misalignment can be prevented.

In the wiring board with a built-in electric element, the height of the protruding terminal electrode is preferably 20 to 65% of the thickness of the insulating layer. By making the electric element built inside the wiring board thinner than the thickness of the insulating layer, the deformation of the insulating layer can be suppressed, and the displacement of the electric element inside the wiring board can be prevented.

In the above-described wiring board with a built-in electric element, it is desirable that the distance between the terminal electrodes closest to the electric element is 400 μm or less. By forming a condensed portion made of conductive particles as the connection portion of the electric element, the deformation and spread of the bonding agent, such as when using a bonding agent such as solder or a conductive adhesive, can be suppressed. The distance between the wiring circuit layer and the terminal electrode of the electric element can be reduced.

In the wiring board with a built-in electric element, the electric element is preferably a multilayer capacitor formed by alternately laminating internal electrode layers and dielectric layers.

If the electric element incorporated in the wiring board is a multilayer capacitor, the capacitance and inductance of the wiring board can be effectively controlled by using a more miniaturized electric element. Usability can be enhanced.

The manufacturing method of the wiring board with a built-in electric element of the present invention is as follows.
(A) a step of forming a protruding terminal electrode on at least one main surface of the electric element, and (b) a step of forming an insulating sheet containing an uncured or semi-cured thermosetting resin and an inorganic filler; c) forming a conductive particle-dispersed insulating sheet containing an uncured or semi-cured thermosetting resin and conductive particles, and (d) forming a via-hole conductor at a predetermined position of the insulating sheet containing the inorganic filler. (E) forming a transfer sheet in which a wiring circuit pattern made of a metal foil is formed on the surface of a flexible film; and (f) transferring to the surface of the insulating sheet obtained by the (d) step. (G) a step of thermocompression bonding the sheet to form a wiring circuit sheet on which a wiring circuit pattern is formed;
(C) a step of thermocompression-bonding the transfer sheet to the surface of the conductive particle-dispersed insulating sheet obtained in the step to form a conductive portion forming wiring circuit sheet on which a wiring circuit pattern is formed; (h) (f) A) laminating at least one layer of the conductive part forming wiring circuit sheet obtained in the step (g) between the layers of the plurality of wiring circuit sheets obtained in the step; A step of preparing a temporary laminate in which an electric element is placed at a predetermined position between layers between the sheet and the sheet; and (i) heating and pressurizing the temporary laminate to be included in the insulating sheet and the conductive particle-dispersed insulating sheet. Curing the thermosetting resin and forming a condensed portion containing conductive particles in the extending direction of the protruding terminal electrode formed on the electric element.

According to this manufacturing method, the previously formed wiring circuit pattern is transferred to the uncured insulating sheet,
The wiring circuit pattern is formed by being buried on the surface thereof, and the wiring substrate can be easily formed by batch curing.

Further, the terminal electrodes of the electric element and the wiring circuit patterns and via-hole conductors formed on the wiring board are joined together at the time of curing, so that the electric element can be built in the wiring board at a time.

Furthermore, by using a conductive particle-dispersed insulating sheet formed by mixing conductive particles and a thermosetting resin as the insulating layer with which the electric element contacts, a bonding agent such as solder or a conductive adhesive is used. The electric element can be easily connected to the wiring circuit layer of the wiring board and the via-hole conductor without providing the wiring board.

According to the manufacturing method of the present invention, it is not necessary to process a via-hole conductor connected to an electric element or a wiring circuit layer, so that the manufacturing cost can be reduced.

In the method of manufacturing a wiring board with a built-in electric element,
In the step (c), the ratio of the conductive particles in the insulating layer is 5
In this step, the content of the conductive particles in the insulating layer is set in this range, so that the terminal electrodes of the electric element and the wiring circuit layer or the via hole conductor are formed in the pressurizing and heating step. The condensed portion of the conductive particles formed between them can be easily formed, and a highly conductive condensed portion can be formed.

In the above-described method of manufacturing a wiring board with a built-in electric element,
In the step (c), the conductive particles are made of Ag, Cu, Ni.
It is desirable to be made of one or an alloy selected from Au and Au.

In this step, a condensed part having high conductivity can be easily formed because the conductive part is made of the conductive particles having high conductivity as described above.

In the method of manufacturing the wiring board with a built-in electric element,
In the step (c), the conductive particles are preferably substantially spherical particles. In this step, the conductive particles contained in the insulating sheet are made substantially spherical, so that the thermosetting resin contained in the insulating layer at the contact point between the conductive particles at the time of pressurizing and heating can be easily removed, and the condensing section Can be improved in electrical connectivity.

In the above-described method of manufacturing a wiring board with a built-in electric element,
In the step (c), the average particle size of the conductive particles is 10 μm.
It is desirable that: In this step, by using conductive particles having a smaller particle diameter than the thickness of the insulating layer, a condensed portion composed of the conductive particles can be easily formed by heating and pressurizing. The difference in electrical resistance between the parts can be increased.

In the method of manufacturing a wiring board with a built-in electric element, the electric element preferably has a protruding terminal electrode on at least the main surface side of the electric element.

In this step, since the terminal electrodes are convex, the density of the condensed portion can be easily increased by forcibly pushing in the conductive particles during heating and pressurization, and the terminal electrodes of the electric element and the wiring circuit Electrical connectivity with the layer and via-hole conductor can be improved.

In the method of manufacturing a wiring board with a built-in electric element, the thickness of the electric element is desirably 50 to 95% of the thickness of the insulating layer. In this step, by forming the terminal electrode higher from the main surface of the electric element, during pressurizing and heating, the conductive particles are forcibly pushed in, so that the density of the condensed portion of the conductive particles can be further increased, The electric resistance of the condensing part can be reduced, and the electrical connection between the electric element and the wiring board can be improved.

In the above-mentioned method of manufacturing a wiring board with a built-in electric element, the thickness of the protruding terminal electrode is preferably 20 to 65% of the thickness of the insulating layer. In this step, the thickness of the electric element incorporated inside the wiring board is smaller than the thickness of the insulating layer, and the protrusion of the terminal electrode has a height in this range, so that the deformation of the insulating layer can be suppressed, and In addition, an electric element can be incorporated.

In the method of manufacturing a wiring board with a built-in electric element, the electric element preferably has a plurality of terminal electrodes, and the distance between the terminal electrodes closest to the terminal electrodes is preferably 400 μm or less. In this step, since it can be connected to the electric element without using a bonding agent such as solder or conductive adhesive, deformation and spreading of the bonding agent can be suppressed, and a short circuit between the terminal electrodes due to the bonding agent can be prevented. The distance between the terminal electrodes of the electric element can be reduced.

In the above-described method for manufacturing a wiring board with a built-in electric element, it is preferable that the electric element is a multilayer capacitor formed by alternately stacking internal electrode layers and dielectric layers. In this step, if the electric element is a multilayer capacitor, it can be easily reduced in size, can be easily incorporated into the wiring board even when it is cured at once, and the capacitance and inductance of the wiring board can be effectively controlled.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Structure) One embodiment of the wiring board with a built-in electric element of the present invention will be described in detail with reference to the schematic sectional view of FIG. The wiring board A according to the present invention includes an insulating substrate 7 on which insulating layers 1, 3, and 5 containing at least an organic resin are laminated.
But the insulating layer 5 located between the insulating layers 1 and 3
Contains conductive particles 19. Also, the insulating substrate 7
The wiring circuit layers 8 and 9 are formed on both surfaces of the insulating layer 1 and the insulating layers 1 and 3.
Are formed. The via-hole conductors 11 are connected to the wiring circuit layers 8 and 9 on the surface of the insulating substrate 7 and the wiring circuit layer 1 inside the insulating substrate 7.
3, 15 are electrically connected.

The insulating layers 5 are provided on the wiring circuit layers 13 and 15.
A projection 25 is formed on the side of the wiring board A. When the conductive particles 19 in the insulating layer 5 are pushed by the projection 25, a condensation via 23 made of the conductive particles 19 is formed. 13 and 15 and between the wiring circuit layers 8 and 9 are connected without forming a via-hole conductor.

Further, the projections 2 contacting the condensation via 23
The height of the insulating layer 5 is 50 to 95% of the thickness of the insulating layer 5, particularly 50 to 95%, in order to suppress the deformation of the condensation via 23 and increase the conductivity.
~ 70% is desirable.

An electric element 17 is embedded between the insulating layer 1 and the insulating layer 5 containing the conductive particles 19, and the electric element 17 is made of the conductive particles 19 formed inside the insulating layer 5. It is connected to the wiring circuit layer 15 on the upper surface side of the insulating layer 5 via the condenser 21.

In this manner, a wiring board with a built-in electric element including the electric elements 17 connected by the condensing portion 21 composed of the conductive particles 19 is formed.

The conductive particles 19 forming the condensed portion 21 in the insulating layer 5 prevent conduction failure due to shortage of the conductive particles 19 and short-circuit due to excessive amount of the conductive particles 19, It is desirable that the content be 5 to 30% by volume in volume fraction because a connection portion having low electric resistance is formed. In particular, the amount of the conductive particles 19 in the insulating layer 5 is more preferably 10 to 25% by volume because the electric resistance is reduced and the impedance matching is stabilized.

The conductive particles 1 forming the condensing portion 21
Desirably, 9 is made of one selected from Ag, Cu, Ni and Au, or an alloy thereof. By using such a low-resistance metal, the electrical resistance of the condensing portion 21 formed by the conductive particles 19 can be suppressed low. In particular, C is preferred because of its high conductivity and low cost.
u is preferably used. Further, an Ag—Cu alloy can be used for the purpose of improving migration resistance.

Further, the shape of the conductive particles 19 forming the condensing portion 21 makes it easy to remove the thermosetting resin contained in the insulating layer 5 at the contact points between the conductive particles 19, so that the electric conductivity of the condensing portion 21 can be reduced. Spherical or substantially spherical particles are desirable because they can enhance the physical connectivity. The conductive particles 19 formed of spherical or substantially spherical particles as described above.
Has a uniform particle size, but more preferably has a particle size distribution because the packing density of the condensing section 21 is increased.

The average particle size of the conductive particles 19 is preferably smaller than the thickness of the insulating layer and equal to or less than 10 μm, because the size of the condensing portion 21 at an arbitrary position of the insulating layer 5 is made uniform. In particular, the average particle size of the conductive particles 19 is 1 to 5 because the electric resistance is made uniform.
μm is desirable.

The electric element 17 is, for example, as shown in FIG. 2, an electric element main body 3 formed by alternately laminating a plurality of internal electrode layers 30a, 30b and a plurality of dielectric layers 31a, 31b.
2 and four terminal electrodes 27a, 27b, 29a, 29b provided at the four corners of the electric element body 32, respectively.
And the internal electrode layer 30a is provided with the terminal electrode 2
7a and 27b, and the internal electrode layer 30b alternately laminated with the internal electrode layer 30a form terminal electrodes 29a and 2a.
9b.

As described above, the terminal electrodes 27a, 27
b, 29a and 29b are formed from the end face to the main face of the electric element main body 32, the terminal electrode 27
The numbers and intervals of a, 27b, 29a, 29b can be arbitrarily changed.

In this example, one electric element 17 is incorporated, but a plurality of electric elements 17 can be incorporated in the wiring board A of the present invention.

The terminal electrodes 27 a, 27 b, 29 a, and 29 b formed at the end of the electric element 17 are connected to the condensing section 2 formed by the conductive particles 19 inside the insulating layer 5.
1 is formed immediately below the terminal electrodes 27a, 27b, 29a, and 29b, it is preferable that the electrode 1 be formed in a projecting shape in the direction of the main surface of the electric element 17, and furthermore, the terminal electrode formed in this projecting shape 27a, 27b, 29a, 2
It is desirable that the top 33 of 9 b is flattened in parallel with the main surface of the electric element 17 because the conductive particles 19 can be uniformly pushed in the thickness direction of the insulating layer 5.

The thickness of the electric element 17 is 50 to 95% of the thickness of the insulating layer. This is because the electric element 17 built in the wiring board A is made thinner than the insulating layer. This is desirable because the deformation of the insulating layer 5 and the insulating layers 1 and 3 can be suppressed, and the displacement of the electric element 17 inside the wiring board A can be prevented. Further, the thickness of the electric element 17 with respect to the thickness of the insulating layer 5 is desirably 60 to 80%.

The terminal electrodes 27a, 27b, 29a,
When the height of the protrusions 29b is 20 to 65% of the thickness of the insulating layer, the forced indentation of the conductive particles 19 can be strengthened, and the density of the condensing portion 21 can be further increased.
1 is preferable because the electrical resistance of the electrical element 17 can be reduced and the electrical connectivity between the electrical element 17 and the wiring board A can be increased. Then, the terminal electrodes 27a, 27b, 29a, 2
The height of 9b is particularly preferably 30 to 50%.

Further, with respect to the terminal electrodes 27a, 27b, 29a and 29b formed on the electric element 17, it is desirable that the distance between the closest terminal electrodes (the distance between the peripheral edges of the adjacent terminal electrodes) is 400 μm or less. . In the case where the electric element 17 incorporated in the wiring board A is connected by the condensing portion 21 formed of the conductive particles 19 as described above, the electric element 17 and the wiring circuit layer 13 of the wiring board A 15 and via-hole conductors 11 and can be suitably used because it is not necessary to apply a bonding agent such as a solder having a large volume or a conductive adhesive again. In particular, the distance between terminal electrodes is 50 to 350 μm. Is desirable because insulation between the terminal electrodes can be ensured.

Further, as the electric element 17 incorporated in the electric element built-in wiring board B, a chip component is preferably used because the electric element 17 which satisfies both miniaturization and high capacity can be formed at the same time. In particular, it is desirable to use a multilayer capacitor as shown in FIG. 2, but in addition, a chip resistor and a chip inductor can also be suitably used. The multilayer capacitor is formed by alternately laminating a ceramic dielectric layer mainly composed of BaTiO ₃ and internal electrodes made of a base metal such as Ni or Cu or a noble metal such as Ag or Pd.

A plurality of multilayer capacitors can be built in a parallel circuit. In this case, the capacitance can be improved and the inductance can be reduced.
When a plurality of capacitors are incorporated, multilayer capacitors having different capacitances can be incorporated, and further, chip components other than the multilayer capacitors can be incorporated at the same time.

(Material) As the material of the insulating substrate 7 in the wiring board A of the present invention, a ceramic insulating material made of a so-called sintered body, or an insulating component, as long as the above-described electric element built-in structure can be formed. Any one of an organic insulating material containing at least an organic resin may be used, but an electric element 17 having a plurality of electrodes formed in advance may be used.
In order to form a structure in which is embedded in the substrate, a material containing an organic resin that does not require a firing step, particularly an insulating material composed of an inorganic filler and an organic resin, is desirable.

The insulating layers 1 and 3 of the insulating substrate 7 in the wiring board A are made of a composite of a thermosetting resin and an inorganic filler. The inorganic filler, for example,
At least one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , AlN, and SiC can be suitably used.

When SiO ₂ is used as the inorganic filler, the relative permittivity of the insulating layers 1 and 3 can be reduced. Further, when Al ₂ O ₃ is used as the inorganic filler, the thermal conductivity of the wiring board A can be increased. In particular, in order to perform high-speed transmission for the purpose of miniaturization and high performance of electronic devices, it is desirable to use SiO ₂ having a low dielectric constant.

The thermosetting resin contained in the insulating layers 1 and 3 is polyphenylene ether (APP).
E) At least one selected from the group consisting of a resin, an epoxy resin, a polyimide resin, a fluorine resin, a phenol resin and a cyanate resin is preferable. APPE
The resin is particularly preferable because it has a low relative dielectric constant, a low dielectric loss, a low water absorption, and a high glass transition point, and thus has high heat resistance. Further, the mixture may contain a dispersant or a coupling agent to improve the wettability with the filler.

In the composite material of the thermosetting resin and the inorganic filler, it is desirable that the organic resin and the inorganic filler are combined in a volume ratio of 50:50 to 95: 5. Further, the surface of the inorganic filler may be subjected to a coupling treatment in order to improve the wettability with the organic resin.

Further, if the insulating layers 1 and 3 are formed of a composite material of a thermosetting resin and an inorganic filler, the mechanical strength as well as the thermal stability of the insulating sheet can be increased. Also, compared to a normal glass-epoxy substrate, etc.
Since the filler is not fibrous, the interface between the filler and the organic resin can be isolated, so that migration does not easily progress and insulation reliability can be improved.

On the other hand, in the insulating layer 5 composed of a composite of the conductive particles 19 and the thermosetting resin, the conductive particles 1
9 is preferably made of one selected from Ag, Cu, Ni and Au or an alloy thereof, but the proportion of the conductive particles 19 constituting the insulating layer 5 is 5 to 30% by volume with respect to the organic resin, It is particularly desirable that the content be 10 to 25% by volume. The ratio of the conductive particles 19 is limited to the above range. When the content of the conductive particles 19 is lower than 5%, the conductive particles 19 between the electric element 17 and the wiring are not sufficiently condensed and the conductive This is because it becomes impossible to secure a path for performing the operation. On the other hand, if the content of the conductive particles 19 exceeds 30% by volume, the conductive particles 19
This is because a short circuit occurs between the upper and lower wirings due to the occurrence of the above-mentioned path, or the insulative property that can withstand the reliability cannot be secured.

As the organic resin used for the insulating layer 5, the same resin as the thermosetting resin used for the insulating layers 1 and 3 is used because the curing temperature is the same and the shrinkage behavior during curing is matched. It is desirable.

As the metal foil for forming the wiring circuit layers 8, 9, 13, and 15 of the wiring board A of the present invention, copper having high conductivity, easy to finely process, and relatively inexpensive is preferable. Used for

The conductive paste formed on the via-hole conductors 11 formed on the insulating layers 1 and 3 includes at least one or more selected from the group consisting of copper, silver, aluminum and gold, particularly copper. Powder, a copper powder coated with a silver powder, a copper-containing powder such as a copper-silver alloy powder, or a Sn powder or Sn-Ag-Cu-Bi
The tin-containing powder is added to the via-hole conductor 11 because the tin-containing powder is melted at the time of heat curing in the manufacturing process by adding the tin-containing powder to the copper-containing powder. And the wiring circuit layer 8,
9, 13 and 15 can be easily connected, and an intermetallic compound composed of Cu ₃ Sn or Cu ₆ Sn ₅ having excellent heat resistance can be generated and can be firmly connected.

(Manufacturing Method) Next, a method of manufacturing a wiring board with a built-in electric element will be described with reference to the process chart of FIG.

Insulating sheets 41 and 43 serving as insulating layers 1 and 3
Is a thermosetting resin such as an imide resin, a polyphenylene ether-based resin, or an epoxy-based resin, and SiO ₂ , Al ₂ O ₃
It is made from a mixed material with an amorphous inorganic filler such as (a).

On the other hand, the conductive particle-dispersed insulating sheet 45 serving as the insulating layer 5 is made of a thermosetting resin such as a polyphenylene ether resin or an epoxy resin similar to those used for the insulating sheets 41 and 43, Ag, Cu, At least one kind of conductive particles 1 among conductive particles 19 such as Ni and Au;
9 to form a mixture. (A).

Next, the insulating sheet 4 which becomes the insulating layers 1 and 3
Via holes 47 are formed in 1 and 43 by using a carbon dioxide laser or punching (b).

Next, the via holes 47 formed in the insulating sheets 41 and 43 are filled with a conductive paste containing Cu powder to form via-hole conductors 49 (c).

Thereafter, the electric elements 17 are placed on the surfaces of the insulating sheets 41 and 43 and the conductive particle-dispersed insulating sheet 45.
And a wiring circuit pattern 51 is formed on the upper surface thereof to form a wiring circuit sheet 55 and a conductive portion forming wiring circuit sheet 57 containing conductive particles (d).

These wiring circuit patterns 51 are made of a metal foil such as a copper foil or an Al foil, for example.
After the transfer to the surface, a method of forming a predetermined wiring circuit pattern 51 by the steps of resist application, exposure, development, etching, and resist removal, or in advance, the insulating sheets 41, 43 on the surface of a flexible film There is a method of transferring to the surface. Among them, the latter method is preferable because the insulating sheets 41 and 43 are not exposed to an etchant or the like and the insulating sheets are not deteriorated.

Next, using the plurality of wiring circuit sheets 55, the conductive part forming wiring circuit sheet 57 and the electric element 17, the electric element 17 is formed by a method as shown in FIG.
Is manufactured.

First, the wiring circuit sheet 55 is placed on the lowermost layer, and then the conductive part forming wiring circuit sheet 57 is laminated on the upper surface side of the wiring circuit sheet 55. Then, the electric element 17 is placed on the upper surface side of the conductive portion forming wiring circuit sheet 57. In this case, the terminal electrodes 27 a, 27 b, 29 a, 29 b formed at the end of one main surface of the electric element 17 face the conductive part forming wiring circuit sheet 57 side, and the wiring circuit formed on the upper surface of the wiring circuit sheet 55. It is placed so as to contact directly above a predetermined connection portion in the pattern 51.

Next, the wiring circuit sheet 55 is again laminated on the upper surface side of the electric element 17 to form a temporary laminate. In this case, the insulating sheets 41 and 43 in the B-stage state
While heating the conductive particle-dispersed sheet 45 to 70 to 200 ° C., a pressure is applied so that the electric element 17 can be embedded in the surface of the insulating sheet. The pressure for embedding the electric element 17 is 1 kg / cm ² or more, especially 2 to 20 kg / cm 2.
The range of kg / cm ² is desirable.

As described above, the provisional laminate is placed on the insulating sheet 4
Preliminary heating and pressurization are performed at a temperature lower than the temperature at which the thermosetting resin in the conductive particle-dispersed insulating sheet 45 is cured.
By forming a condensing portion 21 made of the conductive particles 19 inside the conductive particle-dispersed insulating sheet 45 immediately below 27b, 29a, and 29b, and then performing main curing at a temperature at which the thermosetting resin is cured. , Built-in electric element 17 and wiring circuit layers 8, 9, 13, 15 formed on insulating layers 1, 3
In addition to increasing the density of the condensing portion 21 between the substrate and the insulating layer 1, the adhesion to the surfaces of the insulating layers 1 and 3 is strengthened, and the deformation of the wiring board A during the curing process can be suppressed. Can be made.

(Operation) In the wiring board with a built-in electric element configured as described above, the insulating layer 5 laminated between the plurality of insulating layers 1 and 3 contains the conductive particles 19 and the electric element 17
Is electrically connected to the via-hole conductor 11 on the wiring board A side and / or the wiring circuit layers 8, 9, 13, and 15 via the condensing portion 21 formed of the conductive particles 19, thereby forming the wiring board. A wiring circuit layers 8, 9, 13, 15
And via-hole conductor 11 and terminal electrode 27 of electric element 17
a, 27b, 29a, and 29b can be connected without using a bonding agent such as solder or a conductive adhesive, so that deformation and spreading of the bonding agent during heating and pressing can be suppressed, and the electric element 17 and the wiring board can be connected. A, wiring circuit layers 8, 9, 13, 1
5 and the via-hole conductor 11 can be improved in connectivity.

The terminal electrodes 27a, 27b, 29a,
Condensing section 21 containing conductive particles 19 surely at position 29b
Can be formed, and the wiring circuit layers 8, 9, 13, 15 and the via-hole conductor 11 inside the wiring board A and the terminal electrodes 27a, 27b, 29a, 29b of the electric element 17 can be connected without displacement. An increase in the electric resistance of the wiring board A can be suppressed, and the impedance matching can be improved.

Further, since the number of via hole processing steps can be reduced, the manufacturing cost can be reduced.

[0079]

EXAMPLE First, as a built-in electric element, for example, a ceramic capacitor was manufactured as follows. BaTiO
_An internal electrode pattern was screen-printed on the surface of a plurality of ceramic dielectric sheets of the ₃ series using a Ni metal paste. Thereafter, the sheets were heated at a temperature of 55 ° C. and a pressure of 1
The laminate was brought into close contact with each other at 500 Pa, cut in a green state using a cutter, and then fired at a temperature of 1250 ° C. in a reducing atmosphere to produce a multilayer capacitor. In addition, it was confirmed that the internal electrode was exposed from the end face of the capacitor.

Further, a Cu / Ni paste was applied to the end faces of the capacitor elements where the internal electrodes were exposed, and baked at a temperature of 850 ° C. to the end faces of the capacitors. Are formed. The size of this multilayer capacitor is 1.6 mm ×
The size was 1.6 mm × 0.2 mm, the capacitance was 10 nF, and the self inductance was 80 pH. That is, the thickness of the built-in multilayer capacitor was 0.2 mm, and the terminal electrode spacing was 50 μm and 150 μm.

Next, a wiring board incorporating the above-mentioned multilayer capacitor was manufactured as follows.

First, an amorphous S-PPE resin was
The iO ₂ powder was mixed with a resin in a varnish state so as to have a predetermined ratio, and the thickness was adjusted to 12 mm by a doctor blade method.
A plurality of 0 μm insulating sheets were produced.

Next, an A-PPE resin and conductive particles made of Cu powder were mixed, and an insulating sheet containing conductive particles having a thickness of 500 μm was produced by the same molding method as that for the insulating sheet containing an inorganic filler. The ratio of the conductive particles in the insulating layer was 5 to 35% by volume. The average particle size of the conductive particles used here was 5 to 10 μm.

Next, via holes (0.1 mm in diameter) were formed in these insulating sheets by a carbon dioxide gas laser.
The via hole was filled with a conductive paste containing Cu powder to form a via hole conductor.

Next, polyethylene terephthalate (PE)
T) applying an adhesive to the surface of the transfer sheet made of resin,
A copper foil having a thickness of 12 μm and a surface roughness of 0.8 μm was bonded to one surface. Then, apply a dry film resist, expose,
After the development, the non-pattern portion was removed by etching using a spray-type etching apparatus using a ferric chloride solution to prepare a transfer sheet on which a wiring circuit pattern made of copper foil was formed.

Thereafter, the wiring circuit pattern side of this transfer sheet was pressure-bonded at 130 ° C. and 20 kg / cm ² to produce a wiring circuit sheet having a wiring circuit pattern formed on the surface of an insulating sheet.

Next, by using the plurality of wiring circuit sheets and the electric elements, a laminated body containing one electric element was manufactured.

First, a wiring circuit sheet containing an inorganic filler was placed on the lowermost layer, and then a conductive part forming wiring circuit sheet containing conductive particles was laminated on the upper surface side of the wiring circuit sheet containing the inorganic filler.

Next, the electric element 17 was mounted on the upper surface side of the conductive part forming wiring circuit sheet containing the conductive particles. In this case, the terminal electrodes formed at the ends of the one main surface of the electric element face the conductive portion forming wiring circuit sheet containing the conductive particles,
In addition, the printed circuit board is placed so as to be in contact with immediately above a predetermined connection portion in the printed circuit pattern formed on the upper surface of the printed circuit sheet.

Next, on the upper surface side of this electric element placed on the upper surface side of the conductive portion forming wiring circuit sheet containing the conductive particles,
Again, the wiring circuit sheets containing the inorganic filler were laminated to form a temporary laminate.

Then, the temporary laminate is heated and pressurized at a temperature of 130 ° C. and a pressure of 20 kg / cm ² to embed the electric element 17 on the surface of the conductive portion forming wiring circuit sheet containing the conductive particles. At a temperature of 200 ° C and a pressure of 20 kg / cm
^The main curing was performed under the conditions of ² to prepare a wiring board with a built-in electric element. At this time, the thickness of the insulating layer 5 in which the condensed portion 21 formed by the conductive particles 19 was changed to 400 μm after curing.

As a comparative example, an insulating sheet prepared by mixing a thermosetting resin and an inorganic filler for all of the insulating layers constituting the insulating substrate was used, and via-hole conductors and wiring circuit layers of the insulating sheet were formed. Then, a sample in which the electric elements were connected using a conductive adhesive was prepared. The following study was performed on the manufactured wiring board with built-in electric elements.

Using an impedance analyzer, the frequency characteristic of the impedance is measured at a frequency of 1.0 MHz to 1.8 GHz, the capacitance of the capacitor at 1 MHz is measured at the same time, and f ₀ = 1 / (2π
(L / C) ^1/2 , where f _{0 is the} resonance frequency (Hz),
Based on C: capacitance (F) and L: inductance (H), the inductance was calculated from the resonance frequency (L (room temperature)). A temperature cycle test between −45 ° C. and 125 ° C.
The test was repeated to evaluate the rate of change in inductance and insulation resistance of the wiring board after the test. The insulation resistance was measured using an insulation resistance meter at an applied voltage of 10 V and a value of 1 minute after the application time.
Table 1 shows the results. The number of samples was n = 10 in each evaluation item.

[0094]

[Table 1]

As is clear from the results shown in Table 1, the sample N in which a condensed portion composed of conductive particles was formed in the insulating layer was obtained.
o. 3 to 18, the capacitance is 10 nF or more, the resonance frequency is 77 MHz or more, and the inductance obtained from these values is 140 pH or less.
In the T test, swelling was observed in some of the samples after the TCT test.
0% or less.

[0096] Sample No. 1 was prepared in which the content of the conductive particles was 10 to 25% by volume. In Nos. 3, 5 to 18, the change rate of the inductance after the TCT test was 10% or less, indicating good characteristics.

In particular, the content of the conductive particles is 20 to 30% by volume, and the ratio of the thickness of the electric element to the thickness of the insulating layer is 60 to 80%.
% Sample No. In 7 to 9, 11, 12, and 17, the capacitance is 10 nF or more and the inductance is 110
Below pH, the rate of change of inductance in the TCT test is 6
% And the rate of change in insulation resistance in the TCT test is 5%
It was found that the connection between the electric element built in the wiring board and the wiring circuit layer was good.

On the other hand, among the samples in which the electric elements were joined by using a conductive adhesive, the sample No. in which the interval between the electric elements was 150 μm. In No. 2, the capacitance was obtained, but the increase in insulation resistance after the TCT test was large. When the interval between the terminal electrodes was 50 μm, a short circuit occurred after the sample was produced.

[0099]

As described above in detail, in the wiring board with a built-in electric element according to the present invention, the electric element is connected to the via-hole conductor and / or the wiring circuit on the wiring board via the condensing portion formed by the conductive particles. By being electrically connected to the layers, the connection can be performed without using a bonding agent such as solder or a conductive adhesive. The connectivity with the internal wiring circuit layer and via-hole conductor can be improved.

Further, the insulating layer for connecting the electric elements does not require via hole processing, so that the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a wiring board with a built-in electric element of the present invention.

FIG. 2 is a perspective view of a built-in electric element.

FIG. 3 is a process chart for explaining an example of a method for manufacturing the wiring board with a built-in electric element of the present invention in FIG. 1;

[Explanation of symbols]

A ········ Wiring board 1, 3, 5 ··· Insulating layer 7 ..... Insulating substrate 8, 9, 13, 15 ..... Wiring circuit layer 11, 49 ..... Via-hole conductor 17 ... ·············································································································································· 23 ..... Condensed vias 27a, 27b, 29a, 29b .. Terminal electrodes 41, 43 .. Insulating sheet 45 ..・ ・ ・ ・ ・ ・ ・ ・ ・ Conductive particle dispersed insulating sheet 47 ・ ・ ・ ・ ・ ・ ・ Via hole 49 ・ ・ ・ ・ ・ ・ ・ Via hole conductor 51 ... Circuit pattern 55 Wiring circuit sheet 57 Conductive part forming wiring circuit sheet 59・ ・ ・ ・ ・ ・ ・ ・ ・ Laminate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/46 H05K 3/46 T 1/11 N // H05K 1/11 3/32 B 3/32 H01L 23/12 BNF term (reference) 5E317 AA24 BB02 BB03 BB12 BB22 CC25 CD27 GG03 5E319 AA01 AA03 BB11 CC61 CD26 GG15 5E346 AA04 AA12 AA15 AA22 AA32 AA35 AA43 AA51 BB11 BB16 CC32 CC08 EE15 EE18 FF01 FF18 FF50 GG15 GG19 GG22 GG28 HH07 HH11 HH31

Claims (20)

[Claims] An insulating substrate formed by laminating an insulating layer containing at least an organic resin, a plurality of wiring circuit layers formed on the surface and / or inside of the insulating substrate, and at least metal inside the insulating substrate. In a wiring board with a built-in electric element having a built-in electric element having a terminal electrode inside a wiring board having a via-hole conductor filled with a component,
Among the plurality of insulating layers, at least one of the insulating layers contains conductive particles, and a terminal electrode of the electric element has a via-hole conductor on the wiring board side and / or via a condensing portion of the conductive particles. An electric element built-in wiring board, which is electrically connected to a wiring circuit layer. 2. The wiring board with a built-in electric element according to claim 1, wherein the proportion of the conductive particles in the insulating layer is 5 to 30% by volume. 3. The conductive particles are made of Ag, Cu, Ni and A.
3. The wiring board with a built-in electric element according to claim 1, wherein the wiring board is made of one selected from u or an alloy thereof. 4. 4. The wiring board with a built-in electric element according to claim 1, wherein the conductive particles are substantially spherical particles. 5. The wiring board with a built-in electric element according to claim 1, wherein the average particle size of the conductive particles is 10 μm or less. 6. The wiring board with a built-in electric element according to claim 1, wherein the electric element has a protruding terminal electrode on at least the main surface side of the electric element. 7. The thickness of the electric element is 50 to 95 times the thickness of the insulating layer.
%. The wiring board with a built-in electric element according to claim 6. 8. The height of the protruding terminal electrode is 20 to 65% of the thickness of the insulating layer.
3. The wiring board with a built-in electric element according to claim 1. 9. The electric element according to claim 6, wherein the distance between the nearest terminal electrodes is 400 μm or less.
9. The wiring board with a built-in electric element according to claim 8. 10. A built-in electric element according to claim 6, wherein the electric element is a multilayer capacitor formed by alternately laminating internal electrode layers and dielectric layers. Wiring board. 11. A step of (a) forming a protruding terminal electrode on at least one main surface of an electric element, and (b) forming an insulating sheet containing an uncured or semi-cured thermosetting resin and an inorganic filler. (C) forming a conductive particle-dispersed insulating sheet containing an uncured or semi-cured thermosetting resin and conductive particles; and (d) forming the insulating sheet obtained in the step (b). A step of forming a via-hole conductor at a predetermined location, (e) a step of forming a transfer sheet having a wiring circuit pattern made of a metal foil formed on the surface thereof, and (f) a surface of the insulating sheet obtained by the step (d). (E) forming a wiring circuit sheet by transferring a wiring circuit pattern from the transfer sheet formed in the step (e); and (g) forming a conductive particle-dispersed insulating sheet on the surface of the conductive particle-dispersed insulating sheet obtained in the step (c). (E) forming a conductive portion forming wiring circuit sheet by transferring a wiring circuit pattern from another transfer sheet formed in (e); and (h) forming a plurality of wiring circuit sheets obtained by the steps (f) and (f). (G)
Producing a temporary laminate in which at least one layer of the conductive part forming wiring circuit sheet obtained in the step is laminated, and an electric element is placed at a predetermined position between the wiring circuit sheet and the conductive part forming wiring circuit sheet. (I)
The temporary laminate is heated and pressed to cure the thermosetting resin contained in the insulating sheet and the conductive particle-dispersed insulating sheet, and the conductive particles extend in a direction in which a terminal electrode formed on the electric element extends. Forming a condensing section containing: a method for producing a wiring board with a built-in electric element. 12. The method according to claim 11, wherein in the step (c), the proportion of the conductive particles in the insulating layer is 5 to 30% by volume. 13. The method according to claim 13, wherein in the step (c), the conductive particles
13. The method for manufacturing a wiring board with a built-in electric element according to claim 11, wherein the wiring board is made of one kind selected from g, Cu, Ni, and Au or an alloy thereof. 14. The method according to claim 11, wherein in the step (c), the conductive particles are substantially spherical particles.
3. The method for producing a wiring board with a built-in electric element according to any one of the above items 3. 15. The method according to claim 11, wherein in the step (c), the conductive particles have an average particle diameter of 10 μm or less.
A method for producing the wiring board with a built-in electric element according to any one of claims 14 to 14. 16. The method for producing a wiring board with a built-in electric element according to claim 11, wherein the electric element has a protruding terminal electrode on at least the main surface side of the electric element. . 17. The thickness of the electric element is 50 to 9 times the thickness of the insulating layer.
17. The method according to claim 11, wherein the value is 5%.
The method for producing a wiring board with a built-in electric element according to any one of the above. 18. The method according to claim 16, wherein the height of the protruding terminal electrodes of the electric element is 20 to 65% of the thickness of the insulating layer. 19. The electric device according to claim 11, wherein the electric element has a plurality of terminal electrodes, and a distance between the terminal electrodes closest to the terminal electrodes is 400 μm or less. Manufacturing method of wiring board with built-in element. 20. A built-in electric element according to claim 11, wherein the electric element is a multilayer capacitor formed by alternately stacking internal electrode layers and dielectric layers. Manufacturing method of wiring board.