JP2000174405A - Circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board capable of dealing with further making electrical appliances of high-quality and complication by devising mounting means of resistances to increase the mounting area of the circuit board. SOLUTION: In respective circuit boards 2, 4 of a multilayer circuit board 1, through-holes 9a, 9b, 9c, 9d are formed in its thickness direction, and through printings, etc., resistance materials are injected respectively into the through- holes 9a, 9b, 9c, 9d to form in them integrated resistances 11a, 11b, 11c, 11d thereinto. Also, in the multilayer circuit board 1, through-holes 10a, 10b which pass through its entirety in the thickness direction are formed to form in the through-hole 10a the integrated resistance 12a thereinto, by injecting into it a resistance material through printing, etc. Furthermore, by printing a resistance material on the inner surface of the circuit board 4, an integrated resistance (printed resistance) 13a is formed in an inner-layer pattern portion 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board, and is useful when applied to a multi-layer wiring board or the like to increase the mounting area of the board.

[0002]

2. Description of the Related Art FIG. 6 is a rear view showing an example of a conventional wiring board. In the figure, a circuit pattern 32 is screen-printed with a printing ink such as a silver paste, and an LED 33 has printed resistors 34 and 3 on the circuit pattern 32.
5 are connected. The printed resistors 34, 35 are connected to the LED 33 and the circuit pattern 32 by electrodes 36, 37. The electrodes 36 and 37 are branched into electrodes 38 and 39 and electrodes 40 and 41, and the printed resistors 34 and 35 are connected to the LED 33 in parallel.

[0003]

Recently, with the advancement and complexity of electronic equipment, in order to increase the board mounting area, a plurality of wiring boards are pressed and bonded together, or are built on a core board by a build-up method. 2. Description of the Related Art A multilayer printed circuit board has been promoted by stacking insulating layers and forming circuit patterns.

However, conventionally, when a resistor is provided on a multilayer wiring board, the above-described printed resistors 34 and 35 are formed only on the surface of the multilayer wiring board, or a resistance element is mounted. For this reason, in order to cope with the further sophistication and complexity of electronic devices, it has been desired to improve the mounting means of the resistors to increase the board mounting area.

Accordingly, in view of the above prior art, the present invention provides a wiring capable of coping with further sophistication and complexity of electronic equipment by improving the mounting area of the board by devising means for mounting the resistor. It is an object to provide a substrate.

[0006]

Means for Solving the Problems A first method for solving the above problems is described below.
The wiring board of the present invention has a built-in resistance formed by injecting a resistance material into a through hole formed in the wiring board.

The wiring board according to a second aspect of the present invention is the wiring board according to the first aspect of the present invention, wherein the resistance value of the internal resistance is changed by changing the specific resistance of the resistance material or changing the diameter of the through hole. Is set to the value of

A third aspect of the present invention is a wiring board having a multilayer pattern having a surface layer pattern and an inner layer pattern,
It has a printing resistance formed by printing a resistance material on the inner layer pattern portion.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<Structure> FIG. 1 is a sectional view of a multilayer wiring board according to an embodiment of the present invention. As shown in FIG. 1, a multilayer wiring board 1 is formed by laminating wiring boards 2 and 4 with a prepreg material 3 interposed therebetween, and a circuit pattern (hereinafter referred to as a surface pattern) formed on the surfaces of the wiring boards 2 and 4. That)
This is a four-layer multilayer wiring board having circuit patterns 5 and 6 and circuit patterns (hereinafter referred to as inner layer patterns) 7 and 8 formed on the inner surfaces of the wiring boards 2 and 4. .

Each of the wiring boards 2, 4 of the multilayer wiring board 1 has through holes 9a, 9b, 9c,
9d are formed, and these through holes 9a, 9b, 9
A resistance material is injected into each of c and 9d by printing or the like, so that the built-in resistors 11a, 11b, 11c and 11
d is formed. Both ends of the built-in resistors 11a, 11a are connected to the surface layer pattern 5 and the inner layer pattern 7, respectively, and both ends of the built-in resistors 11c, 11d are connected to the surface layer pattern 6 and the inner layer pattern 8, respectively.

Further, through holes 10a and 10b are formed in the multilayer wiring board 1 so as to penetrate the entire multilayer wiring board in the thickness direction, and a resistance material is injected into the through hole 10a by printing or the like. A built-in resistor 12a is formed. Both ends of the built-in resistor 12a are connected to the surface layer pattern 5 and the surface layer pattern 6, respectively.

Further, a built-in resistor 13 is provided in the inner layer pattern 8.
a is formed. The built-in resistor 13a is connected to the wiring board 4
Is a print resistance formed by printing a resistance material on the inner surface of the print head. That is, the multilayer wiring board 1 has the through holes 9a, 9
b, 9c, 9d, 10a, built-in resistors 11a,
This is a multi-layer wiring board of a built-in resistor type having 11b, 11c, 11d, 12a and a built-in resistor 13a formed in an inner layer pattern portion. The built-in resistors 11a, 11b, 11
As a resistance material for forming c, 11d, 12a, and 13a, a printing ink such as a carbon paste can be used.

FIG. 2 and FIG. 3 are explanatory views showing the steps of the manufacturing process of the multilayer wiring board 1. A method for manufacturing the multilayer wiring board 1 will be described with reference to these drawings.

As shown in FIG. 2A, conductive layers 21, 22, 23 and 24 are formed on both surfaces of the wiring boards 2 and 4. As shown in FIG. 2B, the conductive layers 21, 22, 2
3 and 24 are etched into a predetermined pattern to form a surface layer pattern 5, an inner layer pattern 7, and an inner layer pattern 8.
And a surface layer pattern 6 is formed.

As shown in FIG. 2C, through holes 9 a, 9 b, 9 c, 9 d are formed in the wiring boards 2, 4. As shown in FIG. 2D, the through holes 9a, 9b, 9
Resistive materials are respectively injected into c and 9d by printing or the like to form built-in resistors 11a, 11b, 11c and 11d. At this time, in the illustrated example, all the through holes 9a, 9b, 9c, 9
Although a resistance material is injected into the through holes 9a, 9b, 9
The resistance material can be injected by appropriately selecting c and 9d. Further, on the inner surface of the wiring board 4, a built-in resistor 13a, which is a printing resistor, is formed by performing screen printing or the like using a resistor material. This built-in resistor (printing resistor) 13
“a” is slightly thicker than the inner layer pattern 8.

As shown in FIG. 3A, a four-layer multilayer wiring board is formed by pressing the wiring boards 2 and 4 while pressing the prepreg material 3 at the center. As shown in FIG. 3B, through holes 10a and 10b penetrating the entire multilayer wiring board are formed. As shown in FIG. 3C, a built-in resistor 13a is formed by selectively injecting a resistive material into the through-hole 10a by printing or the like, and the through-hole 10b is left as it is. Thus,
The multilayer wiring board 1 is manufactured.

<Function / Effect> The multilayer wiring board 1 having the above-described structure.
According to this, the built-in resistors 11a, 11b,
Since the built-in resistors (printing resistors) 13a are formed in the inner layer pattern portion by forming the 11c, 11d, and 12a, the resistance elements mounted on the surface layer patterns 5 and 6 can be reduced accordingly. That is, a resistor having a fixed resistance value can be a built-in resistor, and another resistor whose resistance value needs to be adjusted can be mounted on the surface layer patterns 5 and 6. Then, since the number of resistance elements mounted on the surface patterns 5 and 6 is reduced, other electronic components can be mounted on the surface patterns 5 and 6.

For this reason, the multilayer wiring board 1 has a larger board mounting area than the conventional one, and can cope with further advancement and complexity of electronic equipment such as a function operation test device.

The built-in resistors 11a, 11b, 11c,
The resistance value of 11d changes the specific resistance of the resistance material,
By changing the diameters of a, 9b, 9c, 9d, and 10a, a desired value can be arbitrarily and easily set. The resistance value of the built-in resistor 13a also changes the specific resistance of the resistance material,
By changing the shape (length, width, thickness), a desired value can be arbitrarily and easily set.

In the case where a resistor is formed by injecting a resistance material into the through hole, various modes such as that shown in FIG. 4 are possible in addition to the mode shown in FIG.

In FIG. 4A, both ends of the built-in resistor 12c formed in the through hole 10c and both ends of the built-in resistor 12d formed in the through hole 10d are connected in the surface layer patterns 5 and 6, thereby forming the built-in resistor 12c. , 12d are arranged in parallel.

In FIG. 4B, by connecting one end of the built-in resistor 12e formed in the through hole 10e and one end of the built-in resistor 12f formed in the through hole 10f in the surface layer pattern 6, the built-in resistors 12e and 12f are connected. Are in series.

In FIG. 4C, the built-in resistor 12i formed in the through-hole 10i is used as it is as a resistor, whereas the built-in resistor 12g formed in the through-hole 10g is no longer necessary. Silver palladium or copper paste) to form the built-in conductive part 20,
By connecting both ends of the built-in conductive portion 20 and both ends of the built-in resistor 12g in the surface layer patterns 5 and 6, short-circuiting occurs.

In FIG. 4D, the internal resistor 11f formed in the through hole 9f and the internal resistor 11e formed in the through hole 9e are shown.
Are connected in the inner layer pattern 8, so that the built-in resistors 11e and 11f are connected in series.

In the above, the case where the present invention is applied to a multilayer wiring board has been described. However, the present invention is not limited to this, and the present invention can be applied to a single wiring board as illustrated in FIG. . In FIG. 5, a single wiring board 1
6, through holes 17a and 17b are formed.
Built-in resistors 18a and 18b are formed by injecting a resistive material into the layers 7a and 17b by printing or the like.
4, 15 are connected. Also in this case, it is possible to increase the substrate mounting area.

When the present invention is applied to a multilayer wiring board, the method of manufacturing the multilayer wiring board is not limited to the above-described manufacturing method, and other manufacturing methods may be used. For example, it may be manufactured by a build-up method. In this case, the through-hole for forming the resistor can be formed by a photographic method or a laser drilling method. When the build-up method is used, the degree of freedom is large because a through-hole can be formed at an arbitrary position and wiring can be freely routed.

[0028]

As described above in detail with the embodiments of the present invention, according to the multilayer wiring board of the first or second invention, the resistance material is injected into the through-hole formed in the wiring board. Because of the formed internal resistance, the number of resistance elements mounted on the surface pattern can be reduced accordingly.
Then, as the number of resistance elements mounted on the surface layer pattern is reduced, other electronic components can be mounted on the surface layer pattern. For this reason, the substrate mounting area increases as compared with the conventional one, and it is possible to cope with further advancement and complexity of electronic devices. Further, the resistance value of the built-in resistor can be arbitrarily and easily set to a desired value by changing the specific resistance of the resistive material or changing the diameter of the through-hole, and the built-in resistor can have various modes. is there.

Further, according to the wiring board of the third invention, the wiring board is a multilayer wiring board having a surface layer pattern and an inner layer pattern, and a built-in resistor (printing resistor) formed by printing a resistive material on the inner layer pattern portion. ),
Accordingly, the number of resistance elements mounted on the surface layer pattern can be reduced. Then, as the number of resistance elements mounted on the surface layer pattern is reduced, other electronic components can be mounted on the surface layer pattern. For this reason, the substrate mounting area increases as compared with the conventional one, and it is possible to cope with further advancement and complexity of electronic devices. Furthermore, the resistance value of the built-in resistor changes the specific resistance of the resistance material, and the shape (length, width,
By changing the thickness, it is possible to arbitrarily and easily set a desired value.

[Brief description of the drawings]

FIG. 1 is a sectional view of a multilayer wiring board according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing an aspect of a manufacturing process of the multilayer wiring board.

FIG. 3 is an explanatory view showing an aspect of a manufacturing process of the multilayer wiring board.

FIG. 4 is a cross-sectional view showing various aspects of a built-in resistor formed on the multilayer wiring board.

FIG. 5 is a sectional view of a single wiring board according to the embodiment of the present invention.

FIG. 6 is a rear view showing an example of a conventional wiring board.

[Explanation of symbols]

Reference Signs List 1 multilayer wiring board 2, 4 wiring board 3 prepreg material 5, 6, 14, 15 surface layer pattern 7, 8 inner layer pattern 9a to 9f, 10a to 10i, 17a, 17b through-holes 11a to 11f, 12a, 12c to 12g, 12i Built-in resistor 12h Built-in conductive part 18a, 18b Built-in resistor 13a Built-in resistor (printing resistor) 16 Wiring board

Continued on the front page F-term (reference) 4E351 AA01 BB05 BB22 BB26 BB27 BB31 BB35 BB49 CC11 DD29 DD52 EE01 FF02 FF03 FF04 GG01 GG20 5E346 AA06 AA41 CC02 CC08 CC25 CC32 DD09 DD13 DD32 DD34 EE01 GG28 GG18 FF18 GG28 HH25 HH31

Claims (3)

[Claims] 1. A wiring board having a built-in resistance formed by injecting a resistance material into a through hole formed in the wiring board. 2. The wiring board according to claim 1, wherein the resistance value of the built-in resistor is set to a desired value by changing a specific resistance of the resistor material or changing a diameter of the through hole. A wiring board, characterized in that: 3. A multilayer wiring board having a surface layer pattern and an inner layer pattern, wherein the wiring board has a printed resistance formed by printing a resistive material on the inner layer pattern portion.