JPH10294565A - Multilayer circuit substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the close adhesive strength with a substrate by a method wherein a via hole electrode is formed by a plurality of child via hole electrodes which are laminated by shifting the center axis of the via hole electrode. SOLUTION: A via hole electrode 12, consisting of a plurality of child via hole electrodes laminated by shifting their center axis, is formed on a substrate 11 to be formed by laminating a plurality of dielectric sheets 11a to 11h, and the via hole electrode is connected to an external electrode 13. A plurality of conductive patterns 14, which constitute an internal circuit, are connected to another via hole electrode 15. As a result, the thermal or mechanical stress concentrated in the via hole electrode can be dispersed to the stress imposed on a plurality of child via hole electrodes to be laminated by shifting their center axis. Accordingly, the adhesive strength between the via hole electrodes, whose one end is connected to the external electrode, and the substrate can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer circuit board used for electronic and communication equipment, and more particularly to a structure of external electrodes for connecting electronic components.

[0002]

2. Description of the Related Art FIG. 10 is a sectional view of a conventional multilayer circuit board. The multilayer circuit board 50 has a substrate 51, and external electrodes 52 are formed on the front and back surfaces of the substrate 51. At this time, the conductor patterns 53 provided on the dielectric sheets 51a to 51c are connected to each other by the via hole electrodes 54. The conductor patterns 53 provided on the dielectric sheets 51 a and 51 c are also connected to external electrodes 52 provided on the front and back surfaces of the substrate 51 by via-hole electrodes 54. Although not shown, the multilayer circuit board 50 is mounted on the mounting board by soldering the external electrodes 52 provided on the back surface of the board 51 and a circuit pattern on the mounting board on which the multilayer circuit board 50 is mounted. Implemented.

[0003]

However, in the above-mentioned conventional multi-layer circuit board, if the adhesion between the via-hole electrode and the substrate is poor and the adhesion strength is low, slight thermal or mechanical stress may cause a problem on the mounting substrate. In this case, there is a problem that the via-hole electrodes together with the external electrodes soldered to the circuit pattern are peeled off from the substrate in such a manner that the substrate is clogged.

The present invention has been made to solve such a problem, and provides a multilayer circuit board capable of increasing the adhesion strength between a substrate and a via-hole electrode whose one end is connected to an external electrode. The purpose is to:

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a substrate formed by laminating a plurality of dielectric sheets or magnetic sheets, and external electrodes formed on the front and back surfaces of the substrate. And at least one via-hole electrode having one end connected to the external electrode, wherein the via-hole electrode comprises a plurality of sub-via-hole electrodes stacked with their central axes shifted.

Also, a substrate formed by laminating a plurality of dielectric sheets or magnetic sheets, external electrodes formed on the front and back surfaces of the substrate, and at least one via hole electrode having one end connected to the external electrode are provided. Wherein the via-hole electrode comprises a plurality of child via-hole electrodes having different shapes.

Also, a substrate formed by laminating a plurality of dielectric sheets or magnetic sheets, external electrodes formed on the front and back surfaces of the substrate, and at least one via-hole electrode having one end connected to the external electrode are provided. And a dummy electrode that does not constitute an internal circuit is connected to the other end of the via hole electrode.

According to the multilayer circuit board of the present invention, another dummy electrode which does not constitute an internal circuit is provided at an intermediate portion of the via hole electrode. The via-hole electrode, one end of which is connected to the via-hole electrode, is composed of a plurality of child via-hole electrodes stacked with their central axes shifted or a plurality of child via-hole electrodes having different shapes, so that the via-hole electrode is concentrated via the external electrode. Thermal or mechanical stress can be distributed to the plurality of via-hole electrodes.

Further, since a dummy electrode which does not constitute an internal circuit is connected to the other end of the via hole electrode having one end connected to the external electrode formed on the front and back surfaces of the substrate, the via electrode is concentrated on the via hole electrode via the external electrode. Thermal or mechanical stress can be distributed to the dummy electrodes.

[0010]

FIG. 1 is a sectional view of a first embodiment of a multilayer circuit board according to the present invention. Multilayer circuit board 10
Is formed on a substrate 11 formed by laminating a plurality of dielectric sheets (11a to 11h) mainly containing barium oxide, aluminum oxide, and silica;
A via-hole electrode 12 composed of a plurality of sub-via-hole electrodes 12a stacked with their center axes shifted, an external electrode 13 formed on the front and back surfaces of the substrate 11, and one end of the via-hole electrode 12 connected thereto, It is formed of a conductor pattern 14 formed and constituting an internal circuit, and another via hole electrode 15 connecting the plurality of conductor patterns 14.

Next, a method for manufacturing the multilayer circuit board 10 will be described. First, a plurality of mother dielectric sheets made of ceramic are prepared. Then, in such mother dielectric sheets, the respective central axes are shifted in a laminated state, that is, so that the via-hole electrodes 12 can be formed.
Alternatively, a via hole is formed by punching so as not to shift, that is, another via hole electrode 15 can be formed, and the conductor pattern 14 is formed on the mother dielectric sheet by screen printing of a conductor paste.

When the conductor paste of the conductor pattern 14 is printed, a sub via hole electrode 12a that forms the via hole electrode 12 by filling the via hole with the conductor paste, and another via hole electrode that connects the conductor pattern 14 to each other. 15 are formed.

Next, the plurality of mother dielectric sheets are laminated and pressed to form a mother substrate, and a conductive paste serving as an external electrode 13 connected to one end of the via hole electrode 12 is screen-printed on the surface of the mother substrate. I do.

Next, after the mother substrate is cut into blocks, the substrate 11, the via hole electrodes 12, the external electrodes 13,
By integrally firing the conductor pattern 14 and another via hole electrode 15, a multilayer circuit board 10 including a via hole electrode 12 including a plurality of sub via hole electrodes having different central axes therein is completed.

According to the multilayer circuit board of the first embodiment described above, the via-hole electrodes, one ends of which are connected to the external electrodes formed on the front and back surfaces of the board, have a plurality of sub-layers which are stacked with their central axes shifted. As shown in FIG. 2 (enlarged view of the circled portion in FIG. 1), thermal or mechanical stress A concentrated on the via-hole electrode via the external electrode is stacked with the central axis shifted as shown in FIG. The stress can be dispersed to the stress B applied to the plurality of sub via hole electrodes. Therefore, it is possible to improve the adhesive strength between the substrate and the via hole electrode having one end connected to the external electrode.

The amount of deviation of the central axis of the plurality of sub via hole electrodes is suitably 30% to 70% of the diameter of the sub via hole electrodes. For example, if the deviation amount of the central axis of the plurality of sub via hole electrodes is set to 50% of the diameter of the sub via hole electrodes,
It is an aggregate of a plurality of child via-hole electrodes, and the bonding strength between the via-hole electrode whose one end is connected to the external electrode and the substrate is:
About 20% improvement.

FIG. 3 shows a second example of the multilayer circuit board according to the present invention.
1 shows a cross-sectional view of the embodiment. The multilayer circuit board 20 includes a substrate 21 formed by laminating a plurality of dielectric sheets (21a to 21h) made of ceramic, and a plurality of child via hole electrodes 22a formed inside the substrate 21 and having different shapes.
A via hole electrode 22, an external electrode 23 formed on the surface of the substrate 21 and connected to one end of the via hole electrode 22, a conductor pattern 24 formed inside the substrate 21 and forming an internal circuit, and a plurality of conductors. And another via-hole electrode 25 for connecting the pattern 24.

The multilayer circuit board 2 having the above-described configuration
No. 0 is manufactured by the same manufacturing method as the multilayer circuit board 10 (FIG. 1) of the first embodiment.

According to the multilayer circuit board of the second embodiment described above, the via hole electrode having one end connected to the external electrode formed on the front and back surfaces of the substrate is composed of a plurality of child via hole electrodes having different shapes. As shown in FIG. 4 (enlarged view of the circled portion in FIG. 1), the thermal or mechanical stress A concentrated on the via-hole electrode via the external electrode is applied to the stress B applied to a plurality of child via-hole electrodes having different shapes. Can be dispersed. Therefore, it is possible to improve the adhesive strength between the substrate and the via hole electrode having one end connected to the external electrode.

FIG. 5 shows a third embodiment of the multilayer circuit board according to the present invention.
1 shows a cross-sectional view of the embodiment. The multilayer circuit board 30 includes a substrate 31 formed by stacking a plurality of dielectric sheets (31a to 31h) made of ceramic, and a via hole electrode 32 formed inside the substrate 31 and penetrating through each of the dielectric sheets 31a to 31h. And an external electrode 33 formed on the surface of the substrate 31 and connected to one end of the via hole electrode 32, and a dummy electrode 34 formed inside the substrate 31 and connected to the other end of the via hole electrode 32 and not forming an internal circuit. And a conductor pattern 35 formed inside the substrate 31 and constituting an internal circuit.
And the other via hole electrode 36 connecting the plurality of conductor patterns 35.

Next, a method of manufacturing the multilayer circuit board 30 will be described. First, a plurality of mother dielectric sheets made of ceramic are prepared. Next, via holes are formed in these mother dielectric sheets by punching, and dummy electrodes 34 and conductive patterns 35 are formed on predetermined mother dielectric sheets of the mother dielectric sheets by screen printing of a conductive paste. .

The dummy electrode 34 and the conductor pattern 3
When the conductive paste of No. 5 is printed, the conductive paste is filled in the via holes, so that the other end of the dummy electrode 34 is formed.
Via electrode 32 and conductor pattern 3 connected to
5 are connected to each other.

Next, the plurality of mother dielectric sheets are laminated and pressed to form a mother substrate, and a conductive paste serving as an external electrode 33 connected to one end of the via-hole electrode 32 is screen-printed on the surface of the mother substrate. I do.

Next, after the mother substrate is cut into blocks, the substrate 31, via hole electrodes 32, external electrodes 33,
By integrally firing the dummy electrode 34, the conductor pattern 35, and another via hole electrode 36, the multilayer circuit board 30 including the dummy electrode 34 therein is completed.

FIG. 6 is a sectional view showing a modification of the multilayer circuit board 30 shown in FIG. FIG. 6A shows a first modified example,
This is a case where a plurality of via hole electrodes 32 are provided between the external electrode 33 and the dummy electrode 34. FIG. 6B shows a second modification, in which one dummy electrode 34 is shared by a plurality of external electrodes 33.

According to the multilayer circuit board of the third embodiment, the dummy electrode which does not constitute an internal circuit is connected to the other end of the via hole electrode, one end of which is connected to the external electrode formed on the front and back surfaces of the substrate. Therefore, as shown in FIG. 7 (enlarged view of the circled portion in FIG. 5), the thermal or mechanical stress A concentrated on the via hole electrode via the external electrode can be dispersed into the stress B applied to the dummy electrode. it can. Therefore, it is possible to improve the adhesive strength between the substrate and the via hole electrode having one end connected to the external electrode.

FIG. 8 shows a fourth example of the multilayer circuit board according to the present invention.
1 shows a cross-sectional view of the embodiment. The multilayer circuit board 40 is different from the multilayer circuit board 30 of the third embodiment (FIG. 5) in that another dummy electrode 41 is provided also in an intermediate portion of the via hole electrode 32.

According to the multilayer circuit board of the fourth embodiment, another dummy electrode which does not constitute an internal circuit is also provided at an intermediate portion of a via hole electrode having one end connected to an external electrode formed on the front and back surfaces of the substrate. As shown in FIG. 9 (enlarged view of the circled portion in FIG. 8), thermal or mechanical stress A concentrated on via-hole electrodes via external electrodes is applied to a plurality of dummy electrodes. Can be dispersed. Therefore, the adhesive strength between the via hole electrode having one end connected to the external electrode and the substrate can be further improved.

In the multilayer circuit boards of the first to fourth embodiments described above, the case where the external electrodes are formed by firing integrally with the mother board has been described. External electrodes may be formed on the front and back surfaces by printing and baking.

Further, the case where the dielectric sheet constituting the substrate mainly contains barium oxide, aluminum oxide, and silica has been described. In addition, a dielectric sheet mainly containing titanium oxide and neodymium oxide, nickel, There are magnetic sheets mainly containing cobalt and iron.

Further, in the multilayer circuit boards of the first and second embodiments described above, the cross-sectional shape of the child via hole electrode may be any of a round shape, an elliptical shape, a rectangular shape, and the like.

Further, in the multilayer circuit boards of the third and fourth embodiments described above, the case where the via hole electrode having one end connected to the external electrode is connected only to the dummy electrode which does not constitute the internal circuit has been described. However, the same effect can be obtained even if the via hole electrode is connected to a dummy electrode that does not form an internal circuit and is also connected to a conductor pattern that forms an internal circuit.

Further, as a method of manufacturing a multilayer circuit board,
After cutting the mother substrate into blocks, the substrate, via-hole electrodes, external electrodes, conductor patterns, and another via-hole electrode are integrally fired, or the substrate, via-hole electrodes, external electrodes, dummy electrodes, conductor patterns, and another via-hole electrode are baked. Although the case of integrally firing has been described, after the mother substrate, via hole electrode, external electrode, conductor pattern and another via hole electrode are integrally fired, or after the mother substrate, via hole electrode, external electrode, dummy electrode, conductor pattern and another via hole, After integrally firing the electrodes, the mother substrate may be cut into blocks.

In the multilayer circuit board of the fourth embodiment, another dummy substrate is provided at an intermediate portion of a via hole electrode having one end connected to an external electrode and the other end connected to a dummy electrode. Although described above, the present invention is applied to a via hole electrode composed of a plurality of child via hole electrodes which are stacked with their central axes shifted as shown in FIG. 1 and a via hole electrode composed of a plurality of child via hole electrodes having different shapes shown in FIG. The same effect can be obtained.

[0035]

According to the multi-layer circuit board of the first aspect, the via-hole electrode having one end connected to the external electrode is composed of a plurality of sub-via-hole electrodes stacked with their central axes shifted. Thus, the thermal or mechanical stress concentrated on the via-hole electrode can be dispersed into the stress applied to the plurality of sub via-hole electrodes stacked with the central axis shifted. Therefore, the adhesive strength between the via hole electrode, one end of which is connected to the external electrode, and the substrate can be improved.

According to the second aspect of the present invention, since the via-hole electrode having one end connected to the external electrode is composed of a plurality of child via-hole electrodes having different shapes, the heat concentrated on the via-hole electrode via the external electrode. The mechanical or mechanical stress can be distributed to a plurality of child via-hole electrodes having different shapes. Therefore, the adhesive strength between the via hole electrode, one end of which is connected to the external electrode, and the substrate can be improved.

According to the third aspect of the present invention, since the dummy electrode which does not constitute an internal circuit is connected to the other end of the via hole electrode having one end connected to the external electrode, the via electrode is concentrated on the via hole electrode via the external electrode. Thermal or mechanical stress can be dispersed in the stress applied to the dummy electrode. Therefore, the adhesive strength between the via hole electrode, one end of which is connected to the external electrode, and the substrate can be improved.

According to the fourth aspect of the present invention, another dummy electrode which does not constitute an internal circuit is connected in the middle of the via hole electrode having one end connected to the external electrode. The concentrated thermal or mechanical stress can be dispersed into the stress applied to another dummy electrode. Therefore, the adhesive strength between the via hole electrode having one end connected to the external electrode and the substrate can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a multilayer circuit board according to the present invention.

FIG. 2 is a partially enlarged sectional view showing dispersion of stress in the multilayer circuit board of FIG. 1;

FIG. 3 is a sectional view showing a second embodiment according to the multilayer circuit board of the present invention.

FIG. 4 is a partially enlarged sectional view showing dispersion of stress in the multilayer circuit board of FIG. 3;

FIG. 5 is a sectional view showing a third embodiment according to the multilayer circuit board of the present invention.

6A is a first modified example of the multilayer circuit board of FIG. 5,
(B) It is sectional drawing which shows the 2nd modification.

FIG. 7 is a partially enlarged sectional view showing dispersion of stress in the multilayer circuit board of FIG. 5;

FIG. 8 is a sectional view showing a fourth embodiment according to the multilayer circuit board of the present invention.

9 is a partially enlarged cross-sectional view showing dispersion of stress in the multilayer circuit board of FIG.

FIG. 10 is a cross-sectional view showing a conventional multilayer circuit board.

[Explanation of symbols]

 10, 20, 30, 40 Multilayer circuit board 12, 22, 32 Via hole electrode 12a, 22a Child via hole electrode 13, 23, 33 External electrode 34 Dummy electrode 41 Another dummy electrode

Claims (4)

[Claims] 1. A substrate formed by laminating a plurality of dielectric sheets or magnetic sheets, an external electrode formed on the front and back surfaces of the substrate, and at least one via hole electrode having one end connected to the external electrode. A multilayer circuit board, comprising: a plurality of sub via-hole electrodes which are stacked with their central axes shifted from each other. 2. A substrate formed by laminating a plurality of dielectric sheets or magnetic sheets, an external electrode formed on the front and back surfaces of the substrate, and at least one via hole electrode having one end connected to the external electrode. Wherein the via-hole electrode comprises a plurality of child via-hole electrodes having different shapes. 3. A substrate formed by laminating a plurality of dielectric sheets or magnetic sheets, external electrodes formed on the front and back surfaces of the substrate, and at least one via hole electrode having one end connected to the external electrode. A multilayer circuit board, comprising: a dummy electrode that does not constitute an internal circuit is connected to the other end of the via hole electrode. 4. The multilayer circuit board according to claim 1, wherein another dummy electrode that does not constitute an internal circuit is provided at an intermediate portion of the via hole electrode.