JPS6369295A - Wiring board - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] A wiring board, in which a plurality of conductors are insulated from each other and formed in multiple layers within an insulating board on which circuit components can be mounted, and there is a conductor between at least two of the conductors. By integrally forming the circuit elements necessary for the electric circuit, it is possible to increase the packaging density on the board and to enable high-speed operation of the electric circuit.

[Industrial application field]

The present invention relates to a wiring board, and for example, to a wiring board suitable for mounting electronic circuit components such as ICs and operating the electronic circuit components at high frequencies.

[Conventional technology]

2. Description of the Related Art Conventionally, electronic circuit components such as resistors and capacitors, which should always be connected to predetermined positions for a certain purpose, are mounted on wiring boards used in various electronic devices.

For example, if an electrical circuit formed by electronic circuit components mounted on a circuit board is designed to respond to ultra-high-speed pulses, electronic circuit components that can operate at high frequencies are required on the circuit board. becomes. Such circuit components include terminating resistors for impedance matching, which are necessary for efficiently transmitting high-frequency signals such as ultra-high-speed pulses;
Examples include bypass capacitors that eliminate noise from the power supply system and ensure stable operation of the circuit.

FIG. 3 shows a conventionally commonly used multilayer wiring board. When this wiring board is viewed in cross section, a ground conductor 13 and a ground conductor 14 are formed on the front and back surfaces of an insulator 11 that is integrally formed into a plate. Furthermore, between the two ground conductors 13 and 14 and in the insulator 11, a plurality of power supply lines 15, a signal line 17 in one layer, and a plurality of signal lines 19 in another layer are arranged so as to be insulated from each other. has been done. In this way, the ground conductors 13 and 14 . Power line 15. The signal line 17 and the signal line 19 are formed in multiple layers relative to the insulator 11 .

The above-mentioned terminating resistor is attached to such a wiring board.

The method for mounting circuit components such as bypass capacitors is as follows:
The method described below was proposed. The conventional board and circuit component mounting concepts based on these various methods are
This will be explained using figures.

(a) A method of mounting individual components on the surface of a board.

FIG. 4 shows a method for mounting individual components such as resistors and capacitors on the surface of the substrate. Here, a power supply line 23 and a signal line 25, which are conductors, are formed in an insulator 21 forming a wiring board.

Further, ground conductors 27 and 28 are formed on both sides of this wiring board, and an IC 29 is mounted on the surface thereof. The power input terminal 31 of the IC 29 is connected to the power line 23, and the signal terminal 33 of the IC 29 is connected to the signal line 25, so that the power necessary for the operation of the IC 29 is supplied, and the input of operational signals is provided. Output is now being generated.

A conductor peeling part 35 of a predetermined size is formed in the ground conductor 27 on the surface, and the power input terminal 31 is inserted through it, and a bypass capacitor 37 is installed between the power input terminal 31 and the ground conductor 27. has been done. Also, in the same way,
Another conductor peeling portion 36 of a predetermined size formed in the ground conductor 27
The signal terminal 33 is inserted through the signal terminal 3.
A terminating resistor 39 is installed between 3 and the ground conductor 27.

(b) A method of storing circuit elements in through-holes of a board.

Figure 5 shows through holes (
A method of inserting and storing a circuit element into a hole (corresponding to a hole for forming a through hole) is shown. Now, let's talk about how to form a wiring board! ! A desired wiring pattern 4 is formed on both sides of the board 41.
3 is formed of a conductor. A through hole 45 is formed in the insulating substrate 41 to connect the conductors provided on both sides.
A chip-shaped resistor 49.1 is inserted into the through hole 47 as a terminating resistor and a bypass capacitor. A capacitor 51 is inserted.

(c) A method of incorporating circuit components into an IC placed on a wiring board.

FIG. 6 shows a method of incorporating circuit components such as a terminating resistor and a bypass capacitor into an IC mounted on a wiring board. Even in this method, the IC 60 is mounted on a wiring board formed in the same manner as shown in FIG. This IC6
0, an IC chip 63 is enclosed by the IC case 61. In this IC chip 63, a built-in chip capacitor 65 corresponding to a bypass capacitor and a built-in chip resistor 67 corresponding to a terminating resistor are additionally formed in the element (IC chip 63).

A terminating resistor for impedance matching is necessary for efficiently transmitting high-frequency signals in response to ultra-high-speed pulses using the above-mentioned means.

A bypass capacitor is also installed to eliminate noise from the power supply system and ensure stable operation of the circuit.

[Problem that the invention seeks to solve]

By the way, the conventional method described above has various problems.

First, in the method of mounting a terminating resistor and a bypass capacitor on a wiring board as shown in FIG. 4, the wiring board can be easily manufactured, but the circuit components cannot be mounted at a high density. For example, as the circuit operation by the IC 29 becomes faster, circuit components must necessarily be mounted at a higher density. In particular, when it is necessary to mount the IC chip on a wiring board without using an encapsulated package, the bypass capacitor 37
And the total area occupied by the termination resistor 39 on the wiring board is:
The area is larger than that occupied by an IC chip. Therefore, there is a problem in that it is not possible to improve the packaging density by mounting the IC in the form of a chip.

Further, even in the method shown in FIG. 5, the resistor 49, which is an individual component. The capacitor 51 is inserted into the through hole 45 of the insulating substrate 41.
．． 47. Due to the size of the through-holes 45, 47, there is a limit to the miniaturization of these individual parts, and the through-holes have to be enlarged. Therefore,
As with surface mounting of individual components, there is a problem in that high mounting density cannot be achieved. Also, resistor 49. When mounting the capacitor 51 on the vA board, it is necessary to connect these individual components by soldering or conductive paste, and there is a drawback that the reliability of these connection means is not high.

Furthermore, in the method shown in FIG.
7, and there is no need to provide a separate termination resistor and bypass capacitor when mounting the IC 60, so there is no restriction on increasing the packaging density. However, as shown in FIG. 7, when connecting multiple ICs, the
1C73 and the wiring portion 75 with characteristic impedance Z0.
In this case, a built-in chip resistor 67 is provided at the terminal end of the wiring portion 75. This chip built-in resistor 67
The resistance value R7 is the characteristic impedance Z of the wiring portion 75.
Same as 0. On the other hand, as shown in FIG. 7(B), when the IC connected to the first TC 71 via the wiring portion 75 has a branched configuration such as the 21C 73 and the 31C 77, another wiring portion It is only necessary to connect the second IC 73 and the 31st IC 77 by means of the second IC 751 and form the built-in chip resistor 67 only on the other wiring portion 751 side. That is, there is no need to provide the chip built-in resistor 67 on the input side of the second IC 730.

Therefore, unlike the one-to-one IC connection as shown in Figure 7 (A), when branching from one RC ratio output as shown in Figure 7 (B), it is necessary to change the termination method. There is. Therefore, there was a drawback that the versatility as an IC was impaired. In this way, incorporating circuit elements means that the IC
There was a problem in that the yield of

The present invention was created in view of these points, and is applicable to circuit elements such as impedance matching terminating resistors and bypass capacitors in electrical circuits provided on circuit boards that respond to ultra-high-speed pulses. It is an object of the present invention to provide a wiring board which improves the packaging density of the wiring board and which does not impair the versatility of circuit components such as RCs mounted for circuit operation.

[Means for solving problems]

In order to achieve such an object, the wiring board according to the present invention includes an insulating substrate on which circuit components can be mounted, and a multilayer structure that is insulated from each other and connected to the circuit components inside the insulating substrate. It is integrally constructed to include a plurality of conductors provided in this manner, and a circuit element formed to penetrate through an insulator between at least two of the plurality of conductors.

[For production]

A plurality of conductors are formed in multiple layers and insulated from each other within an insulating substrate on which circuit components can be mounted, and a circuit element is integrally formed between the two conductors.

An electric circuit made up of circuit components mounted on an insulating substrate has a form in which these circuit elements are connected, and high-speed operation is possible.

In the present invention, packaging density is increased by forming circuit elements within an insulating substrate on which circuit components can originally be mounted.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Figure 1 shows the configuration of a wiring board in an embodiment of the present invention. Here, FIG. 1(A) shows the overall configuration in which a bypass capacitor 97 and a termination resistor 99 are formed and connected in an embodiment of the present invention.

In addition, the same figure (B) shows the termination resistor 99 in the figure (A>
The area around the area is shown enlarged. FIG. 5C shows an enlarged view of the vicinity of the bypass capacitor 97 in FIG.

In the figure, a power line 83 and a signal line 85 are formed in an insulator 81 forming a wiring board. Further, a grounding conductor 87 is formed on the front surface of the insulator 81, and a grounding conductor 88 is formed on the back surface, and an I
C89 is installed. Power input terminal 91 of IC89
is connected to the power supply line 83 by passing through a peeled area 92 of a predetermined size in the ground conductor 87 . IC89 signal terminal 93
The ground conductor 87 is also connected to the signal line 85 by passing through another separated area 94 of a predetermined size. As a result, IC8
The power supply necessary for the operation of 9 is supplied, and operational signals are input and output. Further, another power supply line 95 is formed in the insulator 81.

The power input terminal 91 further extends to the opposite side of the power line 830 and is connected to the ground conductor 8 via a bypass capacitor 97.
8 is connected. Further, the signal terminal 93 is connected to the signal line 8
It further extends to the opposite side of 50 and is connected to the power supply line 95 via a terminating resistor 99 .

Note that this IC 89 is an IC consisting only of chips without using an encapsulating package.

Figure 2 shows that in the wiring board formed as shown in Figure 1, a termination resistor for impedance matching and a bypass capacitor are integrally installed on the board on which multiple ICs are mounted so that it can respond to ultra-high speed Hals. The case where it is formed is shown.

In FIG. 2, four ICs 891 to I in chip form are shown.
C894 is mounted directly on the wiring board. Among these, the signal input terminal 93 of IC891
■1 to the signal output terminal 9304 of IC894 and IC89
The signal output terminal 9303 of No. 3 is connected to the signal input terminal 9311□ of the IC 891 and the signal input terminal 93I2 of the IC 892 through signal lines each having a characteristic impedance of Z. During this time, it is assumed that ultrahigh-speed pulse transmission is performed.

Immediately before each input terminal, a terminating resistor 991 (resistance value R1) and a terminating resistor 99 for impedance matching are installed.
2 (resistance value R2) is connected between the signal line and the power supply line 843. This power line 843 is for supplying power (3). Furthermore, each IC has two types of power supply Vl,
V2 is supplied, and necessary power supply lines 841 and 842 are formed.

There is a capacitance W between the power input terminal of each IC and the ground conductor of the board.
Bypass capacitors 971 to 978 with t values 01 to C8 are connected. These capacitors and terminating resistors are formed in a columnar shape extending between the eyebrows in a direction perpendicular to the plane of the substrate, which is the cross-sectional direction of the substrate.

By forming them in the insulator 81 of the wiring board in this manner, the bypass capacitor 97 and the termination resistor 99 necessary for high-speed operation of the IC 89 are individually mounted.

By the way, in order to realize integral formation of the termination resistor 99 mounted in this way, there are two methods: forming a columnar structure by plating a high-resistance metal in a liquid phase, and applying CVD to a metal surface.
There are various resistor forming techniques, such as a method of selectively growing a high-resistance material in a columnar shape using vapor phase growth, and a method of pouring a paste-like high-resistance material into a resistor-forming area, solidifying it, and then sealing it with metal. In this case, the resistance value can be controlled arbitrarily by adjusting the thickness of the resistive material.

Here, as a method for mounting the termination resistor 99, a method for forming a fine columnar resistor will be described.

For example, a metal mixed crystal 1 alloy such as PdAu or PdAg is deposited on a certain layer of the insulator 81 through a mask by electron beam evaporation. Thereby, the termination resistor 99 is formed at the required location.

Thereafter, that layer is formed with a resin that will become the insulator 81. Next, signal lines and other line conductors to be connected to the formed termination resistor 99 are formed on the resin film. Therefore,
This means that the terminating resistor 99 is mounted between the desired line conductors. Note that the resistance value of the terminating resistor 99 in this case can be controlled by changing the composition ratio of metals such as PdAu and PdAg serving as resistance materials.

Furthermore, using a technique such as screen printing, a paste-like resistance material is poured into columnar holes previously provided in the insulator 81 to connect wiring layers, and then sintered. Paste-like resistance materials include RuO□-based paste (such as ceramic, which can withstand high temperatures) and polymer thick film paste of fine particle resistance and polymer particles. These materials are sintered at high temperatures.

For example, in the termination resistor 99, a desired resistance value R (5
Consider the case of realizing 0Ω). Now, the terminating resistor 99
It has a columnar shape with a circular cross section, and its diameter and length are both 100 μm. As a characteristic of the resistive material used, for example, if the sheet resistance value R0 is 15 μm thick, its volume resistivity ρ is 15×1 o−”Ro.Then, the volume resistivity ρ and the terminating resistor 99 Based on the size of , the resistance value R is given as R''Ro xQ,2. Therefore, for example, if the material has RO=250Ω/mouth, R=50Ω can be obtained.

Also, the bypass capacitor 9 mounted as described above
7 is also easy to implement because it can be done in the same way as the terminating resistor 99. In other words, a dielectric material may be used in place of the above-mentioned resistive material, and since these formation techniques are an extension of the current multilayer substrate formation technology, those skilled in the art can easily realize this.

■Summary of the method In this way, a columnar termination resistor 99 and a bypass capacitor 97 are formed between the wiring layers in the insulator 81, and the circuits necessary for the operation of the rc89 mounted on the wiring board are formed. It becomes a formation. In that case, it is not mounted on the surface of the wiring board, nor is it formed inside the I'C 89.

Therefore, the termination resistor 99 and bypass capacitor 97, which are essential for high-speed pulse transmission, are embedded in the wiring board to shorten the wiring required for mounting the circuit elements.

As a result, 1. Attenuation and propagation delay, which are the main factors that limit high-speed operation of electric circuits, can be significantly reduced, and the speed of circuit operation can be increased.

Here, if the embodiment of the present invention is compared with the conventional example, it has the following advantages. First, compared to the case where resistors and capacitors are mounted on the surface of a substrate, the areas occupied by these individual components can be effectively used for other purposes, making ultra-high-density mounting possible.

Furthermore, since the terminating resistor 99 is not built into the IC and the resistance value of the terminating resistor 99 can be set arbitrarily, the I
Regardless of whether or not the termination resistor 99 is connected to C, the versatility of the IC is not impaired.

■、→l、・Shape ILE In the above-described embodiments of the present invention, the shapes of the resistors and capacitors are columnar with a circular cross section. It may also be a columnar one having the following.

Moreover, although an IC is shown as an electronic circuit component mounted on the wiring board according to the embodiment of the present invention described above, other circuit components may be used.

Furthermore, those skilled in the art will easily guess that the present invention has various other modifications.

〔Effect of the invention〕

As described above, according to the present invention, impedance matching terminating resistors, bypass capacitors, etc. necessary for high frequency operation are installed between conductors that are insulated from each other and formed in multiple layers within an insulating substrate on which circuit components can be mounted. By mounting circuit components, the mounting density on the board can be improved, and the versatility of ICs etc. installed for the operation of the circuit is not impaired, so it is extremely useful in practical terms. .

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing the configuration of a wiring board according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view showing the configuration of a wiring board according to an embodiment of the present invention.
Fig. 3 is a cross-sectional view showing a general wiring board, Fig. 4 is an explanatory diagram of a conventional example in which individual components are mounted on the board surface, and Fig. 5 is a diagram showing the inside of a through-hole in the board. Figure 6 is an explanatory diagram of a conventional example in which circuit elements are housed in an IC mounted on a wiring board. Figure 7 is an explanatory diagram of a conventional example in which circuit elements are housed in an IC mounted on a wiring board. FIG. 4 is an explanatory diagram of a case in which a connection is made in a 1-to-2 manner and a case in which a connection is made in a 1:2 manner. In the figure, 11.21.81 is an insulator, 13.27, 87.88 are ground conductors, 15.23.83, 84.95 are power lines, 17.19.
25.85 is a signal line, 29.89.891-894 are ICs. 31.91 is a power input terminal, 33.93 is a signal terminal, 37.97, 971 to 978 are bypass capacitors, 39.99, 991.992 is a termination resistor, 41 is an insulating substrate, 43 is a wiring pattern, 45. 47 is a through hole, 49 is a resistor, 51 is a capacitor, 63 is an IC chip, 65 is a chip built-in capacitor, and 67 is a chip built-in resistor. (A) Explanatory diagram of the example Fig. 1 Fig. 4

Claims (3)

[Claims] (1) An insulating substrate on which a circuit component can be mounted; a plurality of conductors that are insulated from each other and formed in multiple layers inside the insulating substrate so that they can be connected to the circuit component; and the plurality of conductors. 1. A wiring board integrally configured to include a circuit element formed to penetrate through an insulator between at least two of the conductors. (2) The wiring board according to claim 1, wherein the circuit element is a columnar resistance element. (3) The wiring board according to claim 1, wherein the circuit element is a columnar capacitor.