JP2001156419A - Printed-wiring board and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve high-density mounting by reducing the installation area of a resistance element. SOLUTION: Resistor paste 9 is buried into an interlayer insulation film 22, and the resistor paste 9, a conductor part 61 of a first conductor layer, and a conductor part 62 of a second conductor layer are brought into contact with the resistor paste 9, thus composing a resistance element with a part in contact with the conductor part as an electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board on which an electric resistance element made of, for example, a resistor paste is installed, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG.
FIG. 5 is an explanatory view showing a printed wiring board disclosed in Japanese Patent Publication No.
0 is a flat package IC, 41 is a printed circuit board, 42
Is a conductor circuit, 43 is a conductive foil pattern, 44 is a resistor paste having a resistance value, 45 is an insulating film, and 46 is a conduction hole. The above-mentioned conventional printed wiring board includes a printed circuit board 41.
At the bottom of the range where the flat package IC 40 is mounted,
A conductive hole 46 closed on the upper surface, a conductive foil pattern 43, a resistor paste 44 having a predetermined resistance value,
An insulating film 45 covering the conductive portion and the resistor paste is formed.

The above-mentioned conventional printed wiring board uses a surface resistance of the resistor paste 44 to adjust the distance between the opposing electrodes and the electrode area of the resistor paste 44 in contact with the electrodes to obtain a predetermined resistance. Value can be obtained. A resistor is formed by the resistor paste 44 and the conductive foil pattern 43. The sum of the thickness of the resistor and the thickness of the insulating film 45 is such that the resistor enters the gap between the flat package IC 40 and the printed board 41. Since it is thin, a resistor can also be provided below the flat package IC 40, and the component mounting density is improved.

[0004]

The printed wiring board to which the above-mentioned conventional resistor is attached uses the surface resistance of the resistor paste 44 to determine the distance between the opposing electrodes and the resistor paste 44 in contact with the electrodes. In order to obtain a predetermined resistance value by adjusting the area of the resistor, there is a problem that the area of the resistor becomes large.

[0005] When a multilayer printed wiring board is manufactured by laminating an interlayer insulating film on the resistor by press molding or the like, pressure is applied to the resistor. In addition, since the rigidity is lower than that of the conductive foil pattern 43, the resistor paste 44 is cut by the end face of the conductive foil pattern 43, and connection failure between the resistor paste 44 and the conductive thin pattern 43 is likely to occur. There is a problem that the container is not suitable for a process in which pressure is applied such as press molding.

When a printed wiring board provided with such a conventional resistor is used for a long time, moisture in the air is absorbed by the printed wiring board and water easily accumulates at the interface. There is a possibility that moisture and impurity ions penetrate and concentrate at the interface between the printed wiring board 41 and the insulating film 45 and ion migration occurs, and the resistance value changes with time.

[0007] Ion migration means that when a direct current is applied between the conductor patterns 43, the moisture around the printed wiring board with a resistor causes an ionization reaction of the conductive foil metal in the conductive foil, and dendrites the conductive foil metal. (Dendritic precipitate). In order to prevent ion migration, the surface of the conductive foil metal 43 must be subjected to surface treatment such as suppression of ionization reaction, flux, rust preventive agent, plating with a metal having a standard electrode potential higher than that of the conductive foil metal. However, it is difficult to completely prevent ion migration. Further, there is a problem that the surface resistance is easily influenced by impurity ions which easily enter the interface between the resistor paste 44 and the printed wiring board 41 or the insulating film 45 and are concentrated.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a printed wiring board capable of mounting a resistance element in a small area and enabling high-density mounting. In addition, in a multilayer printed wiring board obtained by laminating a conductor layer and an insulating layer, it is possible to obtain a printed wiring board with a resistor, in which poor connection of a resistance element is prevented and ion migration is prevented during use. Aim. Another object of the present invention is to provide a method for manufacturing the printed wiring board.

[0009]

A first printed wiring board according to the present invention comprises: a first conductor layer having a conductor pattern formed thereon; a second conductor layer having a conductor pattern formed therein; A printed wiring board having an interlayer insulating film between the first conductive layer and the second conductive layer, wherein the printed wiring board is embedded in the interlayer insulating film;
A resistor is provided which is in contact with the conductor of the first conductor layer and the conductor of the second conductor layer.

In a second printed wiring board according to the present invention, in the first printed wiring board, a resistor is filled in an interlayer conduction hole provided in an interlayer insulating film.

A third printed wiring board according to the present invention is the first or second printed wiring board, wherein a first conductive layer is formed on a printed board.

In a fourth printed wiring board according to the present invention, in the third printed wiring board, conductor layers are formed on both surfaces of the printed board, and a resistor is embedded between conductor portions of the conductor layer. Things.

According to a fifth aspect of the present invention, there is provided the printed wiring board according to any one of the first to fourth printed wiring boards, wherein the resistor comprises carbon, zinc oxide, copper, silver, gold, or a gold-plated insulator. And a mixed paste with a resin material.

In a sixth printed wiring board according to the present invention, in any one of the first to fifth printed wiring boards, a contact portion between the resistor and the conductor is used as an electrode, and the electrode area is controlled. Things.

According to a seventh printed wiring board of the present invention, in the sixth printed wiring board, the electrodes are smaller than the interlayer conductive holes.

In an eighth printed wiring board according to the present invention, in the second or sixth printed wiring board, an electrode area is controlled by controlling a size of an interlayer conductive hole. .

In a first method of manufacturing a printed wiring board according to the present invention, a step of providing an insulating layer on a first conductive layer having a conductive pattern formed thereon includes the steps of: Providing an interlayer conduction hole at a position to be an interlayer conduction portion,
The method includes a step of filling a resistor in the interlayer conductive hole and a step of providing a conductor portion of a second conductor layer on which a conductor pattern is formed so as to be in contact with the resistor.

According to a second method of manufacturing a printed wiring board according to the present invention, there is provided a step of providing an interlayer conductive hole in an insulating layer and filling a resistor in the interlayer conductive hole; This is a method of providing a step of providing first and second conductor layers via the insulating layer so as to contact the conductor of the first conductor layer and the conductor of the second conductor layer on which the conductor pattern is formed. .

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is an explanatory diagram illustrating a configuration of a printed wiring board according to a first embodiment of the present invention, and FIG. 2 is an enlarged explanatory diagram illustrating a region X surrounded by a dotted line in FIG. In FIGS. 1 and 2, 1
Is a printed circuit board, in which wiring is provided on both sides in the figure, but may be provided on one side. 10 is a conductor pattern, 21 to 23 are first conductor patterns formed thereon,
This is an interlayer insulating film provided between second conductive layers (hereinafter simply abbreviated as conductive layer). The figure shows a state in which a plurality of interlayer insulating films are stacked on both surfaces of the printed circuit board 1 via the conductive layers. Reference numeral 3 denotes a conduction hole in the printed circuit board 1 which is used for electrically joining the laminated layers of the interlayer insulating films provided on both sides of the substrate. Reference numeral 9 denotes a resistor, such as a resistor paste, filled and buried in an interlayer conductive hole formed in the interlayer insulating film 22, and 61 denotes a resistor 9
The conductor portion 62 of the first conductor layer that contacts the conductor 9 is the conductor portion of the second conductor layer that contacts the resistor 9, and the resistor 9 contacts the two conductor portions 61 and 62. Reference numeral 6 denotes an electrode which is a contact portion between the conductor and the resistor in the conductor, and reference numeral 7 denotes an interlayer conductive portion formed on the interlayer insulating film 23.

As described above, in the printed wiring board according to the embodiment of the present invention, the resistor 9 such as a resistor paste is embedded in the interlayer insulating film, and the resistor paste 9 and the resistor paste 9 are brought into contact with each other. Since the resistor 9 is buried in the interlayer insulating film, the resistor 6 has a smaller footprint than the conventional device.

Further, a multilayer printed wiring board was manufactured by similarly laminating an insulating layer on the insulating film in which the resistance element was buried via a conductor layer by, for example, a subtractive method, an additive method or a silver through-hole method. In this case, as shown in FIGS. 1 and 2, the resistance element is buried in the insulating layer, so that the connection failure between the resistor paste and the electrode can be prevented even if pressure such as pressing is applied, as in the conventional case. You.

The conductor layer on which the conductor pattern according to the present invention is formed can be produced by plating, sputtering, screen printing, or the like. Further, as the resistor paste 9 according to the present invention, carbon, zinc oxide, copper,
By using one or a plurality of mixed pastes of a silver, gold, or gold-plated insulator and a resin material, a resistor having a predetermined resistance value in a predetermined volume can be obtained. As a method of burying the resistor in the interlayer insulating film, a resistor may be filled in an interlayer conductive hole provided in the interlayer insulating film, but the hole is formed by a laser such as a carbon dioxide laser or an excimer laser, or a drill. Is possible, and
By using a photosensitive resin as a material of the interlayer insulating film, the above holes can be formed in the interlayer insulating film by a process such as masking, light irradiation, or development. In order to provide a resistor paste as the resistor 9, for example,
For example, it can be installed in the interlayer insulating film by screen printing. After making the above hole in the interlayer insulating film 4,
By improving the adhesion between the resistor paste 9 and the interlayer insulating film 4 by roughening treatment or primer treatment inside the holes, higher solder reflow resistance and an effect of preventing ion migration can be obtained.

In order to obtain a predetermined resistance value, in addition to the type of the resistor paste 9, the area of the electrode 6, which is a conductor contacting the resistor, is appropriately set. As shown in FIG. 2, in order to obtain a predetermined resistance value, in a printed wiring board,
When the contact surfaces of the conductor portions 61 and 62 and the resistor paste 9 fit within the plane of the upper surface or the lower surface of the resistor paste 9, that is, when the area of the electrode 6 is smaller than that of the resistor paste 9, different materials in the current direction are used. The ion migration is prevented because the interface of the metal is eliminated. If the diameter of the interlayer conduction hole of the interlayer insulating film 22 is changed to 1 mm or less and the diameter of the electrode 6 is changed to 1 mm or less, a sufficiently wide resistance value can be obtained. Since the installation area A of the resistor is equal to the area of the hole of the interlayer insulating film, it is apparent that the installation area of the resistor is significantly reduced.

Embodiment 2 FIG. FIG. 3 is an explanatory diagram illustrating a region corresponding to a region shown in an enlarged manner in the first embodiment of the printed wiring board according to the second embodiment of the present invention. In the first embodiment, a predetermined resistance value is obtained by appropriately setting the type of the resistor paste 9 and the area of the electrode 6. In addition to these setting methods, the hole diameter of the interlayer conduction hole of the interlayer insulating film 22 is obtained. Can also be achieved by appropriately changing
In this case, the upper and lower surfaces of the resistor paste 9 are entirely covered with the electrodes 6.
Must be in contact with If the diameter of the interlayer conduction hole of the interlayer insulating film 22 is changed to 1 mm or less, a sufficiently wide range of resistance can be obtained. Since the installation area B of the resistor is equal to the electrode area of the interlayer insulating film 22, it is apparent that the installation area of the resistance element is significantly reduced.

In particular, as in the present embodiment, the interlayer insulating film 2
By appropriately changing the diameter of the second interlayer conduction hole,
When controlling the resistance value of the resistor, the range of the resistance value of the resistor can be set wider than in the first embodiment. Also,
In the present embodiment, when the inside of the interlayer insulating hole is roughened, the surface area of the side surface of the resistor paste 9 increases, and current does not flow through the surface of the side surface of the resistor paste 9.
It flows inside the resistor paste 9. As a result, similarly to the first embodiment, an effect of preventing ion migration can be obtained.

Embodiment 3 FIG. FIGS. 4A to 4E are explanatory views showing a manufacturing method for obtaining the printed wiring board of the first embodiment in the order of steps. In the figure, assuming that 21 is the outermost interlayer insulating film,
(FIG. 4A). Instead of the interlayer insulating film 21, it may be laminated on a printed board. An interlayer conductive hole 30 is formed in a portion of the interlayer insulating film 22 corresponding to the conductor portion 61 of the first conductive layer {FIG. 4B}, and the resistor paste 9 is filled in the hole {FIG. )｝. next,
A conductor portion of the second conductor layer is provided on the surface of the resistor paste 9 (FIG. 4D). Further, an interlayer insulating film 23 is provided, and wiring is performed through the interlayer conductive portion 7 of the interlayer insulating film 23 to perform printed wiring. Manufacture the plate {FIG. 4 (e)}.

FIGS. 5A to 5E are explanatory views showing a manufacturing method for obtaining the printed wiring board according to the second embodiment in the order of steps. In FIG. A printed wiring board is manufactured in the same manner as in FIG. 4 except that the hole diameter is changed. When the resistance value of the resistor is controlled by appropriately changing the diameter of the interlayer conduction hole 30 of the interlayer insulating film 22 as in the present embodiment,
Conductor portion 61 of first conductor layer on outermost interlayer insulating film 21
Is the same as or larger than the hole to be provided, so that the interlayer conduction hole 30 can be easily formed in the interlayer insulating film 22 by laser without damaging the interlayer insulating film 21 by laser.

Embodiment 4 FIGS. 6A to 6E are explanatory views showing another manufacturing method for obtaining the printed wiring board of the first embodiment in the order of steps. First, before lamination, the interlayer insulating film 22 is {FIG. 6 (a)} through which an interlayer conductive hole 30 is previously formed {FIG. 6 (b)} and the resistor paste 9 is filled {FIG. 6 (c)}. First and second body paste 9
6 (d), which is brought into contact with the conductor portions 61, 62 of the conductor layer and combined with the other interlayer insulating films 21 and 23, to produce a printed wiring board by press molding (FIG. 6 (e)). A single-sided or double-sided printed circuit board may be combined.

FIGS. 7A to 7E are explanatory views showing another manufacturing method for obtaining the printed wiring board of the second embodiment in the order of steps. In FIG. 6, an interlayer conductive hole 30 is provided. A printed wiring board is manufactured in the same manner as in FIG. 6 except that the hole diameter is sometimes changed.

In the above embodiment, the description has been given of the case where the resistor paste is buried in the interlayer insulating film. However, even if the resistor paste 9 or the conductor 8 is buried in the conductive hole 3 of the printed circuit board 1, it is called high-density mounting. effective. Furthermore, in the above-described embodiment, the formation of the resistor has been described. However, the present invention is not limited to the resistor paste 9. The capacitor may be formed by using a dielectric, and the interlayer may be formed by using a conductor. It is also possible to form a conductive part.

[0031]

According to the first printed wiring board of the present invention, there are provided a first conductor layer having a conductor pattern formed thereon, a second conductor layer having a conductor pattern formed thereon, and a first conductor layer having the first conductor layer formed thereon. A printed wiring board having an interlayer insulating film between two conductive layers, wherein the printed wiring board is embedded in the interlayer insulating film and is in contact with the conductor of the first conductor layer and the conductor of the second conductor layer. Since the resistor element is provided, the installation area of the resistance element can be reduced, and there is an effect that high-density mounting is possible.

According to a second printed wiring board of the present invention, in the first printed wiring board, the resistor is filled in an interlayer conduction hole provided in an interlayer insulating film, and the installation area of the resistance element is reduced. This has the effect of reducing the size and enabling high-density mounting.

A third printed wiring board according to the present invention is the first or second printed wiring board, wherein the first conductor layer is formed on a printed board, so that the installation area of the resistance element is reduced. This has the effect that high-density mounting is possible.

A fourth printed wiring board according to the present invention is the third printed wiring board according to the third printed wiring board, wherein conductor layers are formed on both surfaces of the printed board, and a resistor is embedded between conductor portions of the conductor layer. Therefore, there is an effect that the installation area of the resistance element can be reduced and high-density mounting is possible.

A fifth printed wiring board of the present invention is the printed wiring board according to any one of the first to fourth printed wiring boards, wherein the resistor comprises carbon, zinc oxide, copper, silver, gold or a gold-plated insulator; Of mixed paste with resin material,
There is an effect that the installation area of the resistance element can be reduced and high-density mounting is possible.

According to a sixth aspect of the present invention, there is provided the printed wiring board according to any one of the first to fifth aspects, wherein a contact portion between the resistor and the conductor is used as an electrode, and the area of the electrode is controlled. Thus, there is an effect that resistance elements having different resistance values can be easily obtained.

According to the seventh printed wiring board of the present invention, in the sixth printed wiring board, the electrodes are smaller than the interlayer conductive holes, and the effect is that ion migration can be prevented.

An eighth printed wiring board according to the present invention is the printed wiring board according to the second or sixth printed wiring board, wherein the electrode area is controlled by controlling the size of the interlayer conductive hole. This has the effect of increasing the resistance value range of the resistance element and improving the yield.

In a first method of manufacturing a printed wiring board according to the present invention, a step of providing an insulating layer on a first conductive layer having a conductive pattern formed thereon includes the steps of: A step of providing an interlayer conductive hole at a position to be a conductive part; a step of filling the interlayer conductive hole with a resistor; and providing a conductive part of a second conductive layer on which a conductive pattern is formed so as to be in contact with the resistor. In the method of performing the process, it is possible to prevent the occurrence of a bonding failure between the electrode and the resistor paste even when pressure from a press or the like is applied to the resistor, and thus to produce a printed wiring board with a resistor easily. .

In a second method of manufacturing a printed wiring board according to the present invention, an interlayer conductive hole is provided in an insulating layer, and a resistor is filled in the interlayer conductive hole. A method of performing a step of providing first and second conductor layers via the insulating layer so as to be in contact with the conductor of the conductor layer and the conductor of the second conductor layer on which the conductor pattern is formed.
Even if the pressure from the press or the like is applied to the resistor, it is possible to prevent the occurrence of poor connection between the electrode and the resistor paste, and to produce a printed wiring board with a resistor easily.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a printed wiring board according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an enlarged part of the printed wiring board according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an enlarged part of a printed wiring board according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating a manufacturing method for obtaining the printed wiring board according to the first embodiment in the order of steps;

FIG. 5 is an explanatory diagram illustrating a manufacturing method for obtaining a printed wiring board according to a second embodiment in the order of steps;

FIG. 6 is an explanatory diagram illustrating a manufacturing method for obtaining the printed wiring board according to the first embodiment in the order of steps;

FIG. 7 is an explanatory diagram illustrating a manufacturing method for obtaining a printed wiring board according to a second embodiment in the order of steps;

FIG. 8 is an explanatory view showing a conventional printed wiring board.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 printed board, 21 to 23 interlayer insulating film, 3 conduction hole, 6 electrodes, 61 conductor portion of first conductor layer, 62 second
Conductor portion of the conductor layer, 7 interlayer conduction portion, 8 conductor, 9
Resistor, 10 conductor pattern, 30 interlayer conduction hole.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Yanagiura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Seiji Oka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F term (reference) in Mitsubishi Electric Corporation 4E351 BB05 BB26 BB49 CC11 CC14 DD04 DD05 DD06 DD11 DD31 EE03 GG12 5E317 AA24 BB01 BB12 BB13 BB14 CC22 CC25 CC31 CC52 CC53 CD32 CD34 GG11 GG14 5E346 AA06 AA12 BB15 DD09 EE01 FF45 GG15 GG19 GG27 GG28 GG40 HH08 HH25

Claims (10)

[Claims] A first conductor layer having a conductor pattern formed thereon, a second conductor layer having a conductor pattern formed thereon, and an interlayer insulating film interposed between the first conductor layer and the second conductor layer. A printed wiring board having, embedded in the interlayer insulating film,
A printed wiring board comprising a resistor in contact with the conductor of the first conductor layer and the conductor of the second conductor layer. 2. The printed wiring board according to claim 1, wherein the resistor is filled in an interlayer conductive hole provided in the interlayer insulating film. 3. The printed wiring board according to claim 1, wherein the first conductive layer is formed on a printed circuit board. 4. The printed wiring board according to claim 3, wherein conductor layers are formed on both surfaces of the printed board, and a resistor is buried between conductor portions of the conductor layer. 5. The resistor according to claim 1, wherein the resistor is carbon, zinc oxide, copper,
The printed wiring board according to any one of claims 1 to 4, wherein the printed wiring board is a mixed paste of a silver, gold, or gold-plated insulator and a resin material. 6. The printed wiring board according to claim 1, wherein a contact portion between the resistor and the conductor is an electrode, and an area of the electrode is controlled. 7. The printed wiring board according to claim 6, wherein the electrodes are smaller than the interlayer conductive holes. 8. The printed wiring board according to claim 2, wherein an electrode area is controlled by controlling a size of the interlayer conductive hole. 9. A step of providing an insulating layer on a first conductive layer having a conductive pattern formed therein, wherein an interlayer conductive hole is provided in the insulating layer at a position to be a conductive part of the first conductive layer and an interlayer conductive part. A method for manufacturing a printed wiring board, comprising: a step of filling a resistor in the interlayer conductive hole; and a step of providing a conductor portion of a second conductor layer on which a conductor pattern is formed so as to be in contact with the resistor. 10. A step of providing an interlayer conductive hole in an insulating layer and filling a resistor in the interlayer conductive hole, wherein the resistor is formed with a conductor portion and a conductor pattern of a first conductor layer having a conductor pattern formed thereon. A method of manufacturing a printed wiring board, comprising the steps of providing first and second conductor layers via the insulating layer so as to contact the conductors of the second conductor layer.