JPH0474851B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to laminated LC filter components. More specifically, the present invention relates to a laminated LC filter component that is equipped with a filter circuit network, has fewer defects, and has good mechanical properties. [Prior Art and Its Problems] Filter circuits have a wide range of applications in electronic circuits. For example, a filter circuit as shown in FIG. 1a has a frequency-attenuation characteristic as shown in FIG. 1b. As can be seen from figure a, such a filter circuit requires a plurality of combinations of a large number of capacitors and inductors, so it is not easy to realize a desired filter circuit by connecting individual circuit elements. One known method for dealing with this problem is to manufacture filter parts by lamination or vapor deposition. but,
A method of simultaneously realizing a large number of circuit patterns through a unified and reasonable manufacturing process has not been successfully achieved except for those with a small number of elements. In particular, no good method has been devised for the coil or inductor portion of the filter component. Furthermore, when combining the parts of the multilayer composite capacitor and the part of the multilayer composite coil by weight, the affinity between the dielectric of the former and the magnetism of the latter is low, and there is a difference between them due to heat shrinkage during firing. This causes problems such as cracks and distortion in the sintered product due to differences in the coefficient of expansion and expansion coefficient. [Object of the Invention] An object of the present invention is to provide a laminated LC filter component with a simplified manufacturing process, fewer defective products, and good mechanical properties. [Summary of the Invention] The multilayer filter component of the present invention includes a multilayer capacitor part in which a plurality of capacitors are built in a dielectric layer and the lead-out portions of their electrodes are exposed on the circumferential surface, and a plurality of coils in a magnetic layer. A laminated inductor part is built in the body and the lead-out part of each coil is exposed on the circumferential surface, and the sintering property is intermediate between the former dielectric layer interface and the latter magnetic layer interface. The lead-out portion of the coil, the lead-out portion of the capacitor, and the external This is a laminated LC filter component formed by forming an external terminal that interconnects a circuit to form a predetermined filter, and the intermediate material layer is preferably made of non-magnetic Cu-Zn ferrite, TiO ₂ or these. Consists of a combination of
More preferably, the intermediate material layer is a combination of non-magnetic Cu--Zn ferrite on the side of the multilayer inductor and TiO ₂ on the side of the multilayer capacitor. According to the present invention, the intermediate material layer has properties intermediate between the magnetic layer and the dielectric layer, which not only prevents cracking and warping due to firing shrinkage, but also prevents cracking and warping due to firing shrinkage. It also acts as a barrier to suppress deterioration of properties due to diffusion of Ni, Cu, etc. [Detailed Description of the Invention] FIG. 2 shows an example of a method for realizing the laminated LC filter circuit of FIG. 1a, which consists of four coils and nine capacitors. However, according to the method described herein, especially the special lamination process of the laminated coil portion, it is possible to easily manufacture a laminated LC filter component having a filter circuit including a larger number of coils and capacitors. The lamination is done by a well-known printing method, the dielectric layer is a paste of dielectric powder such as BaTiO ₃ or TiO ₂ , and the conductor layer for capacitor electrodes and coils is Ag-
It is formed by screen printing using a paste of metal powder such as Pd or Ag. The intermediate material layer is similarly formed by printing from paste. The intermediate material has properties intermediate between the magnetic layer and the dielectric layer, which not only prevents cracking and warping due to firing shrinkage, but also prevents the ferrite material (containing Ni, Cu, etc.) of the magnetic layer. It must also act as a barrier to suppress characteristic deterioration due to diffusion of Ni, Cu, etc. between dielectric layers. However, what satisfies these requirements at the same time is non-magnetic Cu.
Diffusion of Cu, Ni, etc. becomes a problem when using ferrites or those containing Ni. Therefore, it is necessary to design an intermediate material layer that improves all these aspects. Preferred intermediate materials are Cu--Zn ferrite and TiO ₂ powder, and especially when the former is used on the magnetic ferrite side and TiO ₂ on the dielectric side, excellent effects can be obtained. 1 to 15 in FIG. 2 show sequential manufacturing steps of the laminated LC filter component of the example. Note that the drawings emphasize the various patterns exposed on the top surface, and do not pay attention to the thickness.
It is to be understood that it is from a few to a few + μm per layer. Steps (1) to (5) form a multilayer capacitor section. In step (1), a dielectric layer 1 is formed. Actually, it is formed on a substrate with good releasability (not shown). Thereon, in step (2), a capacitance forming electrode conductor 2 having a lead-out portion 3 at the periphery is formed. This pattern is such that a predetermined number of capacitors (nine in the example shown) can be constructed. Next, in step (3), a dielectric layer 4 is formed on the entire surface, and then a capacitance forming electrode conductor layer 5 having a counter electrode is formed. The drawer part 6 is partially in the same position as the drawer part 3 (in order to make four capacitors, which are connected in parallel to each coil in Fig. 1a), and the drawer part 6 is in a different position (Fig. 1). Grounding example of a (To make 5 capacitors connected to GND)
including. In step (5), a dielectric layer 7 is formed on the entire surface.
In this way, the capacitor section 8 is obtained. In step (6), an intermediate material layer 19 is formed on the entire surface of this capacitor section 8. Steps (7) to (20) show a method of forming a coil portion. In step (7), the magnetic layer 10 is formed on the entire surface of the intermediate material layer 19, and then in step (8), half turns of the conductor 11 for forming four coils having lead-out portions 12 are formed. When the conductors 11 are arranged as shown, the thickness can be easily balanced, and moreover, a plurality of coils can be formed at the same time. In step (9), magnetic layers 13 are printed on both sides of the laminate, and in step (10) about half a turn of coil conductor 14 to be connected to the previous coil conductor 11 is printed. Next, a magnetic layer 15 is formed in the central portion. Magnetic layer 1
3 and 15 have some overlapping parts, but the thickness can be generally uniform throughout. Thereafter, about half a turn of the coil conductor 16, the magnetic layer 17, and about half a turn of the coil conductor 18 are laminated in the same manner, and the lead-out part 19 of the conductor 18 is placed on the periphery at a position different from the lead-out part 12. (Steps (11), (12), (13), (14)).
Finally, in step 15, a magnetic layer is formed on the entire surface to complete the lamination. By firing this laminate at a high temperature, a laminate consisting of a composite capacitor section 8, an intermediate material layer 9, and a composite coil section 21 is obtained as shown in FIG. Note that a trimming conductor 21, holes 22, 23 (for inserting magnetic plugs, etc.), etc. may be provided as necessary. Finally, external terminal electrodes T1 to T12 are formed by baking a conductive base. It will be apparent that these external terminals interconnect the coil and capacitor to implement the circuit of FIG. 1a. Example 1 A sintered body with a three-layer structure was manufactured using the nonmagnetic Nz-Cu intermediate material shown in Table 1 as the intermediate layer, BaTiO ₃ as the dielectric layer, and Mn-Zn ferrite as the magnetic layer. , the Cu distribution in the thickness direction was analyzed. A sample without an intermediate material layer was also used as a control. Table 2 shows the results. Those without an intermediate material layer cracked and warped, but those with compositions 1 to 4 did not have this problem. As can be seen from Table 2, copper present in the dielectric layer and magnetic layer generally diffuses to the interface. In addition, when the Cu concentration in the intermediate material increases, the amount of copper present in each layer near the interface increases, including in the dielectric layer, the magnetic material, and the magnetic material, and the same is true when there is no intermediate material layer. It was hot. On the other hand, compositions 1, 2, 3
In this case, Cu is less than in the case without intermediate material. Therefore, it can be seen that compositions 1 to 4 have interfacial Cu concentrations that are not significantly different from those without the intermediate material layer, but are much better in terms of cracking and warping, and furthermore, they do not diffuse the impurity Cu into each layer. The results for composition 4 show that there is no problem even if the intermediate layer contains a considerable amount of Cu. Example 2 Other than using TiO ₂ on the dielectric side and non-magnetic Zn+Cu ferrite having the composition shown in Table 3 on the magnetic side,
A three-layer sintered body similar to Example 1 was made and analyzed.
The results are shown in Table 4 along with the control. It can be seen that with the intermediate material layer having a two-layer structure, diffusion to both sides can be ignored. [Operation and Effect] As described above, according to the present invention, a complicated LC circuit pattern can be easily realized by printing and sintering. Furthermore, products with less distortion due to the use of intermediate materials and fewer defective products can be provided. The effects described above can be achieved, such as the ability to easily perform complex connections between the coil section and the capacitor section using peripheral external terminals. In the above embodiment, one capacitor section and one coil section were used, but it will be clear to those skilled in the art that any number of capacitor sections and coil sections may be combined by interposing an intermediate material layer.

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【table】 [Brief explanation of the drawing]

Figure 1a is a diagram showing the LC filter circuit, Figure 1b is a graph showing the attenuation-frequency characteristics, Figure 21
-15 are sequential process diagrams for manufacturing a laminated LC filter component according to an embodiment of the present invention, FIG. 3 is a perspective view of a component manufactured by the method shown in FIG. 2, and FIG.
It is a completed diagram of the LC filter component.

Claims (1)

[Claims] 1. A multilayer capacitor section in which a plurality of capacitors are built in a dielectric layer and the lead-out portions of their electrodes are exposed on the peripheral surface, and a multilayer capacitor section in which a plurality of coils are built in a magnetic body and each coil is and a laminated inductor part whose lead-out part is exposed on the peripheral surface, and the dielectric and/or the laminated inductor part has intermediate sintering properties between the dielectric layer interface of the former and the magnetic layer interface of the latter. The coil lead-out part, the capacitor lead-out part, and the external circuit are connected to the circumferential surface of the superimposed sintered body with an intervening intermediate material layer interposed therebetween, which has a property of preventing the components of the magnetic material from diffusing into each other. A laminated LC filter component formed by forming external terminals that are interconnected to form a structure. 2. The laminated filter component according to item 1, wherein the intermediate material layer is made of nonmagnetic Cu-Zn ferrite, _TiO2 , or a combination thereof. 3. The multilayer filter component according to item 1, wherein the intermediate material layer is a combination of nonmagnetic Cu-Zn ferrite on the multilayer inductor side and TiO ₂ on the multilayer capacitor side. 4. The filter connects one lead-out end of a predetermined capacitor to a common grounding external terminal, connects it to an external terminal that connects the coils in series, and connects the other lead-out end of these capacitors to the above-mentioned coil in series. 4. The laminated LC filter component according to any one of items 1 to 3 above, which is connected to an external terminal. 5. The multilayer LC filter component according to item 4, wherein the external terminal is formed such that a capacitor other than the predetermined capacitor is inserted between both ends of each coil.