JPH0660134U - Multilayer chip EMI removal filter - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a multilayer chip EMI removal filter that has low cost, good productivity and yield, has a high EMI removal effect, and has no problem in directionality during mounting. [Structure] First, a through hole 4 is formed in a Ni-Zn-Cu ferrite-based ceramic green sheet having a thickness of 60 μm,
The conductor paste containing Ag as a main component is used to print the coil conductor pattern 5 and the capacitance forming electrode pattern 6 by screen printing. Next, these sheets are laminated and pressure-bonded so that the capacitance forming electrode pattern 6 is inserted between the winding patterns of the coil constituted by the coil conductor pattern 5. Next, after firing the obtained laminated body for 1 hour at 900 ° C., an electrode paste containing Ag as a main component is applied to the internal electrode lead-out end faces and side faces, and baked at 600 ° C. for 10 minutes to form external terminal electrodes ( IN terminal 1, OUT terminal 2, G terminal 3)
To form. Next, the surface of the external terminal electrode is plated with Ni and solder.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a multilayer chip EMI removal filter for EMI countermeasures in digital circuits and the like. More specifically, it has an IN terminal and an OUT terminal which are connection terminals as external terminal electrodes, and a G terminal which is a ground terminal. And a laminated chip EMI removal filter having a three-terminal structure.

[0002]

[Prior art]

 In recent years, electronic devices have been rapidly digitized, and along with this, a problem (EMI) due to high frequency noise generated in a digital circuit becomes a problem. Therefore, in the conventional technology, an EMI removal filter is provided in a digital signal line. The EMI was removed by incorporating it.

As a filter for preventing EMI in the above digital circuit, a filter with a three-terminal structure (IN terminal, OUT terminal, G terminal) is generally used, and at present, this EMI removal filter with a three-terminal structure is used. Although manufactured by various methods, it is considered that the multilayer chip EMI removal filter manufactured by using the stacking technology, which has advantages such as small size and surface mounting, will become the mainstream in the future.

As shown in FIG. 5, a laminated chip EMI removing filter having a three-terminal structure manufactured by using such a laminating technique, as shown in FIG. 5, has an end surface of a laminated body 8 formed by laminating ceramic sheets and On the side surface, connection terminals (IN terminal 1, OUT terminal 2) and a ground terminal (G terminal 3) are provided as external terminal electrodes, respectively.

Further, the multilayer chip EMI removal filters that have been developed so far can be classified according to raw materials and circuit configurations. In other words, when classified by raw material, it can be divided into one made of one type of ceramic insulating material (dielectric or magnetic substance) and one made of a composite of two or more types of materials. If classified according to the configuration, it can be classified into a lumped constant type (T-type cubic and π-type cubic) and a distribution constant type.

[0006]

[Problems to be solved by the device]

 However, the conventional laminated chip EMI removal filters having a three-terminal structure classified by the raw material and the circuit configuration as described above have the following problems, respectively.

First, as shown in FIG. 6, for example, a composite type multilayer chip EMI removal filter configured by compounding two or more kinds of materials has a dielectric material 9 (constituting a capacitor portion) and a magnetic material. It can be constructed by compounding the material 10 (which constitutes the inductor portion). Such a multilayer chip EMI elimination filter has the advantage that it has a high degree of freedom in designing the capacitor section and the inductor section, and that it is easy to obtain high capacity and high inductance, but it is a technology that uses simultaneous firing of different materials. However, there is a problem that the yield is low and the cost is high.

In addition, with the recent shift to higher frequencies of signals, filters used for EMI countermeasures for signal lines in particular do not require high capacitance or high inductance, so the merit of the above composite type is small. Has become.

On the other hand, the multilayer chip EMI removal filter made of one type of material can be made of one type of insulating material 11 as shown in FIGS. 7 and 8, for example. Such a multilayer chip EMI elimination filter has an advantage that it is more advantageous in terms of yield and cost than the above-mentioned composite type because the technical difficulty in the manufacturing process is low.

In addition, as shown in FIG. 10 (T-type third order) and FIG. 11 (π-type third order), a multilayer chip EMI removal filter configured by stacking one kind of material as described above is There are a lumped constant type circuit configuration in which the capacitor section and the inductor section are independent, and a distributed constant type circuit configuration in which the inductance and capacitance are dispersed as shown in Fig. 9. Since the noise elimination effect of the circuit configuration is higher than that of the lumped constant type circuit configuration, many EMI elimination filters of the distributed constant type circuit configuration have been proposed.

However, the structure as shown in FIG. 7 (capacitance is acquired in a distributed manner between the capacitor-forming electrode pattern 6 having the side surface lead-out portion and the coil conductor pattern 5 which is the winding pattern forming the coil). In the multilayer chip EMI removal filter having the distributed constant type circuit configuration of (1), the obtained capacitance value is low. In order to compensate for this problem, if the space between the capacitance forming electrode and the winding pattern is narrowed (damage is reduced), the inductance value will change greatly due to the interference with the magnetic flux generated in the coil, and a suitable LC There is a problem that it is extremely difficult to design to obtain the constant.

Further, a multilayer chip EMI removal filter having a distributed constant type circuit configuration having a structure as shown in FIG. 8 (capacitance forming electrode pattern 6 is brought close to the coil conductor pattern 5 to obtain a capacitance) is also provided. There is a problem that the obtained capacity value is low. In order to make up for this problem, if the coil conductor pattern 5 and the capacitance-forming electrode pattern 6 are brought close to each other, the IN-OUT signal side and the G ground side may be affected by bleeding of the conductor pattern during printing. However, there is a problem that the insulation failure is likely to occur.

Further, since the capacitance forming electrode of this EMI removal filter is linear, an inductor component is added to the original circuit (FIG. 9) to easily form a circuit as shown in FIG. There was a problem that there was a high risk of damage.

Furthermore, this EMI removal filter is directional because the ground electrode is formed only on one side surface of the component, which makes it difficult to manufacture and the manufacturing cost is high. Moreover, the mounting direction when mounting on a substrate is high. There was a problem that defects due to mistakes were likely to occur.

As a modification of the EMI removal filter shown in FIG. 8, there is also one in which a capacitance forming electrode is transferred between coil conductor patterns, but such a structure eliminates the above problem of insulation. It does not solve the problem of the inductor component added to the ground electrode side or the problem of directionality.

Therefore, the present invention solves the problems of the above-mentioned conventional techniques, has a low cost, a high productivity and a high yield, has a high EMI removal effect, and has no problem in the directionality at the time of mounting. Intended to provide a filter.

[0017]

[Means for Solving the Problems]

 As a result of earnest research to achieve the above-mentioned object, the present inventor has made a distributed constant type circuit by entirely forming the same ceramic insulating material and forming a capacitor-forming electrode between coil winding patterns. The inventors have found that the above problems can be solved by the configuration, and arrived at the present invention.

That is, according to the present invention, a spiral coil and a capacitance forming electrode are embedded inside an insulator, and an IN terminal and an OUT terminal which are connection terminals and a G terminal which is a ground terminal are provided as external terminal electrodes. In the multilayer chip EMI removal filter having a three-terminal structure, the insulator is made of one kind of ceramic insulating material, the capacitance forming electrode is formed between the coil winding patterns, and a distributed constant type circuit is formed. The present invention provides a laminated chip EMI removal filter characterized by being configured.

[0019]

[Action]

 The multilayer chip EMI removal filter of the present invention is made of the same ceramic insulating material as a whole (for example, ferrite, titanium oxide, glass ceramics, etc.), and the capacitance-forming electrodes are arranged between the coil winding patterns from 1 to 1 if necessary. The capacitor is formed at a plurality of places and the capacitor is formed at a plurality of places. Therefore, the circuit configuration is a distributed constant type as a whole, and its equivalent circuit diagram is as shown in FIG.

Since the multilayer chip EMI removal filter of the present invention having the above-described configuration has the capacitance obtained between the layers of the laminated insulating ceramic sheets, it is possible to obtain a sufficient capacitance value necessary for EMI countermeasures. it can. This is because the ceramic layer formed by the green sheet method or printing method is usually as thin as about 10 μm to several tens of μm.

In addition, the multilayer chip EMI removal filter of the present invention can change the acquired capacitance value by changing the number of the capacitance forming electrodes or the width of the capacitance forming electrodes, so that the design is extremely easy and Since the change in the inductance value due to the change in the design of the capacitance value is small, the design of the inductance value is easy.

Furthermore, the insulating ceramic layer that constitutes the EMI removal filter of the present invention has a proven record as an insulating layer in a multilayer capacitor and the like, and insulation failure is unlikely to occur. Furthermore, since the capacitance forming electrode pattern provided in the EMI removal filter of the present invention has a wide width and a short distance to the grounding portion (grounding terminal electrode), it is difficult to add an inductor component and the noise countermeasure effect is reduced. large.

Furthermore, in the EMI elimination filter of the present invention, the internally formed capacitance forming electrode pattern is drawn out to both side surfaces of the component, and the ground terminal electrodes are formed on both side surfaces of the component (the target structure is a target structure). Therefore, there is no problem of directionality during production and mounting.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by the following embodiments.

[0025]

【Example】

 An example of a method of manufacturing the laminated chip EMI removal filter of the present invention by the green sheet method is shown below.

First, a slurry obtained by mixing a ceramic insulating material made of Ni—Zn—Cu ferrite, polyvinyl butyral resin, and a solvent (a mixture of toluene, ethanol, and IPA) was used, and a slurry having a thickness of 60 μm was obtained by a doctor blade method. A ceramic green sheet 7 was manufactured.

Next, as shown in FIG. 2, through holes 4 for interlayer connection are formed on the green sheet 7 at predetermined positions, and a conductor paste containing Ag as a main component is further used to form a coil by a screen printing method. The conductor pattern 5 and the capacitor forming electrode pattern 6 were printed.

In this embodiment, the print patterns are eight types shown in FIGS. 2A to 2H, but FIGS. 2B and 2C are shown in FIGS. 2G and 2H. 2D and 2E can be combined, the number of print patterns becomes four, and the production efficiency can be improved. Further, usually, a large number of print patterns are formed on the green sheet (multi-take), but in the present embodiment, a case where a print pattern for one chip is formed on the green sheet is shown for convenience. .

Next, the sheet on which the print pattern was formed and the sheet on which the print pattern was not formed were laminated in the following constitution. First, as a dummy sheet, five layers of the green sheet 7 on which the printing pattern is not formed are laminated, and on top of that, FIG. 2 (f), (d), (c), (b), (e), (d), The sheets 7 shown in (c), (b) and (a) were sequentially laminated, and further five green sheets 7 having no printed pattern as a dummy sheet were laminated thereon as a dummy sheet (FIG. 3).

Then, this is pressed at 100 ° C. and 200 kg / cm ² for 60 seconds to be pressure-bonded, and the coil end portion constituted by the coil conductor pattern 5 and the end portion of the capacitance forming electrode pattern 6 (of the lead-out portion) Thus, a laminated body 8 whose end portions were guided to the pair of opposed end surfaces and the pair of opposed side surfaces was obtained (FIG. 4). In the case of the normal multi-cavity production as described above, cutting to the chip size is performed after pressure bonding.

Next, after the obtained laminated body 8 is baked at 900 ° C. for 1 hour, an electrode paste containing Ag f as a main component and containing glass frit is applied to the internal electrode leading end surface and the side surface of the laminated body 8. External terminal electrodes (IN terminal 1, OUT terminal 2, G terminal 3) were formed by baking at 600 ° C for 10 minutes (Fig. 5). Then, the surface of the external terminal electrode was plated with Ni and solder to obtain the multilayer chip EMI removal filter of the present invention (FIG. 1).

[0032]

[Effect of device]

 The multilayer chip EMI removal filter of the present invention can be manufactured at low cost with high productivity and yield. Further, the multilayer chip EMI removal filter of the present invention has a high EMI removal effect and does not have a problem of directionality during production and mounting.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a multilayer chip EMI removal filter of the present invention.

FIG. 2 is a plan view showing a sheet on which a print pattern constituting an example of the multilayer chip EMI removal filter of the present invention is printed.

FIG. 3 is an exploded perspective view of a laminated body showing a laminated aspect of the sheets shown in FIG.

FIG. 4 is a perspective view showing a laminated body obtained by laminating and press-bonding the sheets shown in FIG.

FIG. 5 is a perspective view showing the appearance of a multilayer chip EMI removal filter having a three-terminal structure.

FIG. 6 is an exploded perspective view of a laminated body that constitutes an example of a laminated chip EMI removal filter having a lumped constant circuit configuration.

FIG. 7 is an exploded perspective view of a laminated body that constitutes an example of a laminated chip EMI removal filter having a distributed constant type circuit configuration.

FIG. 8 is an exploded perspective view of a laminated body that constitutes another example of the laminated chip EMI removal filter of the distributed constant type circuit configuration.

FIG. 9 is a circuit diagram showing an example of a distributed constant type circuit.

FIG. 10 is a circuit diagram showing an example of a lumped constant type circuit.

FIG. 11 is a circuit diagram showing another example of a lumped constant circuit.

12 is a circuit diagram showing a circuit in which an inductor component is added to the circuit of FIG.

[Explanation of symbols]

 1 IN terminal 2 OUT terminal 3 G terminal 4 Through hole 5 Coil conductor pattern 6 ... Capacitor forming electrode pattern 7 ... Green sheet 8 ... Laminate 9: Dielectric material 10: Magnetic material 11: Insulating material

Claims (1)

[Scope of utility model registration request] 1. A three-terminal structure in which a spiral coil and a capacitance-forming electrode are embedded inside an insulator, and which have IN terminals and OUT terminals which are connection terminals as external terminal electrodes, and G terminals which are ground terminals. Structured multilayer chip EMI
A laminated filter characterized by being a removal filter, wherein the insulator is made of one type of ceramic insulating material, and a capacitance forming electrode is formed between winding patterns of a coil to form a distributed constant type circuit. EMI removal filter.