JPH09298438A - Emi eliminating filter for laminated chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated chip EMI eliminating filter in which ringing is effectively suppressed so as to prevent circuit malfunction in an excellent way. SOLUTION: Any conductor part between an input electrode 12 and an output electrode 14 of the filter is processed to have high resistance. High resistance processing is applied to coils 52, 54 in Fig. (A), an electrode C13 of a capacitor 60 in Fig. (B), a viahole connection section 76 in Fig. (C), and a viahole connection section 86 and an electrode C12 of a capacitor 80 in Fig. (D). For the high resistance processing, a resistance material employing an Ag-Pd allow and a ruthenium oxide as the major components is used. Thus, the resistance between the input and the output is increased to suppress effectively ringing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated chip type EMI removal filter.

[0002]

BACKGROUND ART Multilayer chip EM used for noise countermeasures
As is widely known, the I removal filter is composed of a combination of a coil (inductor) and a capacitor (capacitor), and a typical structure thereof is shown in FIG.
become that way. FIG. 5 is a partial internal view,
The equivalent circuit is as shown in FIG. In these figures, the multilayer filter 10 includes IN (input) electrodes 12 and OUT (output) electrodes 14 on the left and right, and a dielectric layer 16 and a magnetic layer 18 on the upper and lower sides. In addition, before and after the laminated filter 10, the GND (earth) electrodes 20, 2 are provided.
2 are provided.

Within the dielectric layer 16 is a capacitor electrode 2
4, 26, 28 are provided at appropriate intervals.
Of these, the capacitor electrodes 24 and 28 are connected to the GND electrodes 20 and 22, respectively, and the other capacitor electrode 26 sandwiched between the capacitor electrodes 24 and 28 is connected to the coil side through the via hole 30. In the magnetic layer 18, the coil conductor 32 is spirally connected using a via hole (not shown), one end is connected to the via hole 30 and the other end is connected to the output electrode 14. Although only the output side coil is shown in FIG. 5, the same applies to the input side coil connected to the input electrode 12. Further, as shown in the equivalent circuit of FIG. 6, the input side and the output side are equivalent, and the input and output may be reversed.

[0004]

However, in the background art described above, the combination of only the coil and the capacitor has a small current suppressing effect. For this reason,
The effect of suppressing the ringing on the digital signal is also small, and there are inconveniences such as circuit malfunction. In FIG. 7 (A),
An example of ringing in a digital signal waveform is shown, and ringing occurs in a portion that is ideally flat.

The present invention focuses on the above points,
It is an object of the present invention to provide a multilayer chip EMI elimination filter that can effectively prevent ringing by effectively suppressing ringing.

[0006]

In order to achieve the above object, the present invention is directed to any region between terminals, for example, a part or all of a coil pattern or a capacitor pattern, a hole connecting portion (connection by a via hole or a through hole). Part)
The resistance of part or all of the above, all of the hole connecting portion and part of the capacitor pattern, and all of the hole connecting portion and all of the coil pattern are increased at the time of forming them. The conductor pattern or the hole connection portion having a high resistance is formed of, for example, a material containing at least one of Ag—Pd alloy, ruthenium oxide, nichrome, and chromel as a main component. The conductor pattern of the capacitor is formed in a dielectric layer, and the conductor pattern of the coil is formed in a magnetic layer, a dielectric layer or an insulator layer.

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to Examples. The multilayer chip EMI removal filter is used, for example, for removing noise in a high-speed signal line.

[0009]

[Embodiment 1] First, Embodiment 1 will be described with reference to FIGS. 1 and 2A. FIG. 1A shows a cross section along the via hole of the laminated filter according to the first embodiment, and FIG. 1B shows an electrode pattern on the laminated sheet. An equivalent circuit is shown in FIG.

First, the manufacturing procedure of the laminated filter of Example 1 will be described. (1) Using a resistance paste having a relatively high resistance value, which is contained in a ratio of Ag: Pd = 1: 1 (atomic ratio), on a green sheet of a magnetic material made of Ni-Zn ferrite,
Screen printing was performed with the patterns shown in (B) SE, SF, SG, and SH. Thereby, the coil pattern L10
-L16, L20-L26 are formed, respectively. In addition, in the via holes of the green sheet shown by SD in FIG.
The conductor paste was screen printed. As a result, via holes H14 and H24 on the magnetic body side are formed.

(2) Next, a Ag conductor paste was used to screen print on a green sheet of a dielectric material containing TiO 2 as a main component in a pattern shown by SA, SB and SC in FIG. 1 (B). As a result, the capacitor patterns C10, C12, C14 are formed, respectively. Also,
Of the via holes of the green sheet shown by SD in FIG. 1B, a plurality of green sheets of the dielectric material were screen printed with Ag conductor paste. As a result, the via holes H14 and H24 on the dielectric side are formed.

(3) Next, the green sheets on which the electrodes and via holes were printed as described above were laminated in the order shown in FIG. 1 (B). At this time, an appropriate number of dielectric green sheets with no electrodes printed thereon are stacked on top of the dielectric sheet layer, and an appropriate number of magnetic green sheets without electrodes printed on the bottom of the magnetic sheet layer. Overlaid. Then, the laminated body of the dielectric material and the magnetic material was hot pressed to be integrated. In addition, in the embodiment of FIG. 1, only one pattern is formed on one sheet, but in reality, a large number of identical patterns are arranged and a large number of patterns are taken.

Next, the connection of the conductor patterns in this laminated state will be described with reference to FIG. Explaining from the upper dielectric side, the sheets SA to SC
The capacitor 50 is formed by the capacitor patterns C10 to C14. The capacitor pattern C1
0 and C14 are formed to extend vertically in FIG. 1B so as to be connected to the GND electrodes 20 and 22 (see FIG. 5). Via holes H10 and H20 are formed at both ends of the capacitor pattern C12 sandwiched between them.
As shown in (A), the via hole H12 of the sheet SC,
H22 and a plurality of via holes H14 and H24 of the sheet SD are connected to the magnetic body side.

On the other hand, on the lower magnetic body side, the sheets SE to
The input coil 52 is formed by the SH coil patterns L10 to L16. Coil patterns L10 to L1
6 are connected by via holes H30 to H34 in a spiral shape. It should be noted that the coil pattern L16 is connected to the input electrode 12 (see FIG. 5) so that the coil pattern L16 shown in FIG.
It is extended to the left of (B).

The coils 54 on the output side are formed by the coil patterns L20 to L26 of the sheets SE to SH. The coil patterns L20 to L26 are via holes H4.
0 to H44 are connected in a spiral shape. The coil pattern L26 is formed on the right side of FIG. 1B so as to be connected to the output electrode 14 (see FIG. 5).

Further, the lands L10H and L20H of the coil patterns L10 and L20 are, as shown in FIG.
The plurality of sheets SD are connected to the dielectric side via via holes H14 and H24.

(4) Next, the laminated body thus obtained is cut to obtain an unfired laminated chip. This unfired chip is de-heated, that is, the organic binder contained in the green sheet or paste is removed by heating, and fired at, for example, 900 ° C. to obtain a fired body of a laminated chip. Then, an input electrode, an output electrode, and a GND electrode (see FIG. 5) are formed on the chip fired body by using, for example, Ag conductor paste, and baked at 800 ° C., for example. Further, those electrode terminals are plated with Ni or solder to obtain a finished laminated filter.

As described above, according to the first embodiment, as shown in FIG.
As indicated by a thick line in (A), the conductor pattern portions forming the coils 52 and 54 have a high resistance.

[0019]

Second Embodiment Next, a second embodiment will be described with reference to FIGS. 3 and 2B. FIG. 3 corresponds to FIG. 1 described above, and (A) is a sectional view taken along the via hole,
(B) is an electrode pattern on the laminated sheet. FIG. 2B is an equivalent circuit. In the second embodiment, as compared with the above-described first embodiment, the capacitor pattern C13 on the sheet SB has a U-shaped repeating pattern as shown in FIG. 3B, and this portion has a high resistance. Ag-P
It has a structure formed of a resistance paste of d.
The coil patterns L10 to L16, L20 to L26
Is formed by a normal Ag paste. Thus, according to the second embodiment, as shown in FIG.
Conductor pattern portion C which is one electrode of the capacitor 60
13 has a high resistance, and the coil 62,
All 64 are normal conductors.

[0020]

Third Embodiment Next, a third embodiment will be described with reference to FIG.
Will be described. In the third embodiment, coil patterns L10 to L16 and L20 to L are compared with the first embodiment.
26, via hole patterns H30 to H34, H40 to H
All 44 are formed of normal Ag paste. However, the via hole pattern H1 of the sheet SD of FIG.
4, H24 is Ag-P as a whole on the dielectric side and the magnetic side.
It has a structure formed of a resistance paste of d.
As described above, according to the third embodiment, as shown in FIG. 2C, although the capacitor 70 and the coils 72 and 74 are normal conductors, the via hole connecting portion 76 connecting them has a high resistance. It has been configured.

[0021]

Fourth Embodiment Next, a fourth embodiment will be described with reference to FIG.
Will be described. In the fourth embodiment, as compared with the second embodiment, the via hole connecting portion is made of Ag as in the third embodiment.
It is formed of a resistance paste of -Pd. That is, in the fourth embodiment, as shown in FIG. 2D, the conductor pattern portion C13, which is one electrode of the capacitor 80, and the via-hole connecting portion 86 have a high resistance, and the coil 82 , 84 are both normal conductors.

[0022]

[Embodiment 5] In a fifth embodiment, the coils 52 and 54, which are the high resistance portions in the first embodiment, are Ag:
The conductor pattern is formed by a resistance paste of Pd = 2: 1.

[0023]

[Embodiment 6] Next, in Embodiment 6, the coils 52 and 54, which are the high resistance portions in Embodiment 1, are arranged in an atomic ratio of Ag:
The conductor pattern is formed by a resistance paste of Pd = 1: 2.

[0024]

[Embodiment 7] In a seventh embodiment, the coils 52 and 54, which are the high resistance portions in the first embodiment, are made of a resistance paste containing ruthenium oxide (ruthenium oxide) as a main component instead of Ag-Pd. It is formed of a conductor pattern.

[0025]

[Embodiment 8] Next, Embodiment 8 is a laminated filter in which the magnetic material portion in Embodiment 1 is formed of a dielectric material and the whole is made of a dielectric material.

[0026]

Ninth Embodiment A ninth embodiment is a laminated filter in which an insulating material made of glass ceramic is used as the dielectric material of the eighth embodiment, and the whole is made of the insulating material.

[0027]

COMPARATIVE EXAMPLE Next, as a comparative example, the coils 52 and 54, which are the high resistance portions in the first embodiment, are made into a conductor pattern made of Ag paste instead of Ag-Pd. In other words, the conductor portion is entirely formed of a conductor pattern made of Ag paste, which corresponds to the background art.

Next, when the resistance value and the ringing between the input and output electrodes were measured for Examples 1 to 9 and Comparative Example having the above-mentioned structures, the results shown in Table 1 below were obtained. The ringing voltage is the value of VR shown in FIG.

[0029]

[Table 1]

Considering the results in Table 1, all the examples have significantly lower ringing values than the comparative examples. Example 4 has the lowest ringing value, and Example 3 has the highest ringing value among the examples. That is, ringing is satisfactorily suppressed by any of the examples, and the waveform shown in FIG. 7A becomes as shown in FIG. 7B. FIG. 4 is a graph showing the relationship between the input-output resistance value and the ringing shown in Table 1. As shown in the figure,
It can be seen that the resistance value between the input and output and the ringing are approximately inversely proportional.

Further, comparing Examples 1, 2 and 3, the resistance value between the input and output changes due to the high resistance portion, and the ringing value also changes correspondingly, but it is good in all cases. The effect of suppressing ringing is obtained. Therefore, which part is to have a higher resistance may be appropriately determined in consideration of the manufacturing process, cost and the like. Next, when Examples 1, 5, and 6 are compared, the resistance value between the input and output changes depending on the ratio of the alloy of Ag: Pd, and the ringing value also changes correspondingly, but in any case, it is good. The effect of suppressing ringing is obtained. Therefore, the Ag: Pd ratio may also be set as appropriate.

Next, Examples 1, 5, 6 and Example 7 are different depending on whether the material of the high and low antibody is an Ag-Pd alloy or a ruthenium oxide. Since ruthenium oxide has a higher resistance value than the Ag-Pd alloy, it has a higher effect of suppressing ringing.
Even if it is a g-Pd alloy, ringing is well suppressed, and any material may be used. Next, Example 1,
Comparing 8 and 9, the resistance values between input and output are almost the same, and the ringing values are not so different. Therefore, any of the magnetic material, the dielectric material, and the insulating material may be appropriately determined.

As described above, according to the present embodiment, the ringing is satisfactorily suppressed by increasing the resistance of any part between the input and the output of the filter. Therefore, malfunction of the circuit caused by ringing can be prevented. Further, since the existing conductor portion is made high in resistance without newly providing a resistor in addition to the coil and the capacitor, there is no inconvenience such as a complicated manufacturing process.

[0034]

Other Embodiments The present invention can be variously modified based on the above disclosure, and includes, for example, the following. (1) In the above embodiment, Ag is used as the material for increasing the resistance.
Although -Pd alloy or ruthenium oxide is used, it does not prevent the use of other materials. For example,
A resistive material containing nichrome or chromel as a main component can also be used, and a material containing any one of these four components as a main component may be used.

(2) In the above embodiment, the conductor pattern of the coil or via hole has a high resistance as a whole.
Of course, only a part, for example, only a part of the coil pattern may be increased in resistance, and may be appropriately changed as necessary. Setting whether or not to increase the resistance of the conductor pattern for each laminated sheet is convenient in the manufacturing process. The same effect can be obtained by increasing the resistance of any region between the terminals. It should be noted that as the region where the resistance is increased increases, the effect of suppressing ringing also increases.

(3) The shapes of conductor patterns, the number of laminated layers, the positions of via holes, and the like shown in the above embodiments are not limited to those in the embodiments, and the design may be appropriately changed as necessary. For example, a through hole may be used instead of the via hole. The manufacturing process is also the same.

(4) In the above-mentioned embodiment, the resistance was increased mainly by devising the material, but as shown in the capacitor pattern C13 of FIG. 3B, the pattern shape (including the film thickness) was devised. By doing so, the resistance may be increased.

[0038]

As described above, according to the present invention, the high resistance portion is provided between the input and the output.
The ringing is effectively suppressed, and further, the malfunction of the circuit is effectively prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention. (A) is a sectional view taken along the via hole, and (B) is a plan view of each laminated sheet.

FIG. 2 is a circuit diagram showing a high resistance portion in a main example with a thick line.

FIG. 3 is a diagram showing a second embodiment of the present invention. (A) is a sectional view taken along the via hole, and (B) is a plan view of each laminated sheet.

FIG. 4 is a graph showing the relationship between input-output resistance and ringing in the example.

FIG. 5 is a partially cutaway perspective view showing an example of a laminated chip type EMI removal filter.

FIG. 6 is an equivalent circuit diagram of the filter of FIG.

FIG. 7 is a diagram showing an example of a digital waveform. (A) is a waveform with ringing, and (B) is a waveform after the ringing is suppressed in this embodiment.

[Explanation of symbols]

10 ... Multilayer filter 12 ... Input electrode 14 ... Output electrode 16 ... Dielectric layer 18 ... Magnetic layer 20, 22 ... GND electrode 24, 26, 28 ... Capacitor electrode 30 ... Via hole 32 ... Coil electrode 50, 60, 70, 80 ... Capacitors 52, 54, 62, 64, 72, 74, 82, 84 ... Coils 56, 66, 76, 86 ... Via hole connecting portions C10 to C14 ... Capacitor patterns H10 to H14, H20 to H24, H30 to H34, H
40-H44 ... Via hole L10-L16, L20-L26 ... Coil pattern SA-SH ... Laminated sheet

Claims (4)

[Claims] 1. A laminated chip EMI elimination filter in which sheets having conductor patterns formed thereon are laminated and the conductor patterns are hole-connected to each other so that any region between terminals has a high resistance when formed. Characteristic multilayer chip EMI removal filter. 2. A high resistance portion is formed of an Ag--Pd alloy,
2. The multilayer chip EMI removal filter according to claim 1, which is formed of a material containing at least one of ruthenium oxide, nichrome, and chromel as a main component. 3. The laminated chip EMI according to claim 1, wherein the resistance is increased by a pattern shape.
Removal filter. 4. Among the conductor patterns, a conductor pattern of a capacitor is formed in a dielectric layer, and a conductor pattern of a coil is formed in a magnetic layer, a dielectric layer or an insulating layer. The multilayer chip EMI removal filter according to claim 1, 2, or 3.