JPH0555066A - Fabrication of multilayer ceramic inductor - Google Patents

Abstract

PURPOSE:To provide fabrication of multilayer ceramic inductor in which pattern matching can be made easily with high accuracy when each conductor pattern of coil is formed on a sheet. CONSTITUTION:Inner conductor connecting through-holes 3 and position matching through-holes 2 are made simultaneously at predetermined positions on a green sheet 1, and conductor patterns 5 for respective parts of coil, inner and outer marks 4, 6 for position matching are then printed on an exfoliation film using Ag paste. A step for transcribing the conductor patterns printed on the exfoliation film and a step for laminating the green sheet 1 formed with through-holes are repeated on the green sheet 1 formed with through-holes thus producing a laminate. The laminate is then thermocompressed and unbound and then baked at 900 deg.C in the atmosphere and external electrodes are formed thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a monolithic ceramic inductor, and more particularly to a method for manufacturing a monolithic ceramic inductor characterized by improved lamination accuracy.

[0002]

2. Description of the Related Art The following is one of the methods for manufacturing a monolithic ceramic inductor that has been widely adopted in the past. First, a step of transferring a conductor pattern for each coil portion, which is printed on a release film and becomes a spiral coil when laminated and through-hole connected onto a magnetic ceramic green sheet, and a line width of the coil conductor is larger than that. The step of stacking the magnetic ceramic green sheets having the inner conductor connecting through holes formed at the predetermined positions is alternately performed to form a stacked body. Next, the obtained laminated body is pressure-bonded and then fired, and external electrodes are formed thereon to obtain a laminated ceramic inductor.

According to the above manufacturing method, the internal conductor formed on the substrate 1 is formed on the substrate 1 as shown in FIG. 8A in the step of transferring the conductor pattern of each part of the coil onto the green sheet having the through holes. The connection ends of the conductor patterns 5 at the lower layers of the coil, which are visible through the through holes 3 for connection, serve as a reference for alignment. That is, FIG. 8B
As shown in FIG. 5, carefully check that the connecting ends of the coil conductor parts 5 on the lower layer, which are visible through the through holes 3 for connecting the inner conductor, and the connecting ends of the conductor patterns 5 of the coil parts printed on the release film are orthogonal to each other. It was arranged and transferred.

However, according to the printing method which has been conventionally used, the conductor pattern on each part of the coil printed on the release film is liable to have sagging or scraping, and in particular, the end portion of the pattern is liable to be unclear. Therefore, it becomes more difficult to align the positions of the end portions of the conductor patterns of the coil as they become unclear, so that the alignment accuracy is likely to decrease, which causes deterioration of the characteristics of the coil installed inside.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the above-mentioned conventional techniques, and aligns the pattern of the coil when forming a conductor pattern for each part on a sheet.
An object of the present invention is to provide a method for manufacturing a multilayer ceramic inductor which can be accurately and easily performed.

[0006]

Means for Solving the Problems As a result of intensive research to achieve the above object, the present inventors have formed a through hole for alignment and a conductive pattern for alignment on a magnetic ceramic green sheet and a transfer film, respectively. In addition, when the conductor pattern for each coil portion is transferred onto the sheet, the conductor pattern for alignment printed on the transfer film is arranged at a predetermined position in the through hole for alignment so that the conductor portion for each coil part is arranged. The present invention has been achieved by finding that the patterns are accurately aligned.

That is, according to the present invention, a conductor pattern for each coil portion is formed on a magnetic ceramic green sheet in which through holes for connecting internal conductors are formed, and a spiral coil is formed by stacking and connecting through holes. The method is a method of manufacturing a monolithic ceramic inductor by alternately repeating the steps and the step of laminating the magnetic ceramic green sheets to form a laminated body, press-bonding the laminated body, and then firing and forming external electrodes. hand,
When forming the conductor pattern of each part of the coil on the sheet in which the through holes for connecting the inner conductor are formed, the conductor pattern for alignment in which a constant relative positional relationship with the conductor pattern of each part of the coil is maintained is previously described above. Laminating characterized in that the conductor pattern of each coil portion is aligned by arranging it at a predetermined position in the through hole for alignment formed on the sheet, and the conductor pattern of each coil portion is formed together with the conductor pattern for alignment. A method of manufacturing a ceramic inductor is provided.

[0008]

According to the method of the present invention, when the conductor pattern for each coil portion is transferred and formed on the sheet, the conductor pattern for alignment is arranged at a predetermined position in the through hole for alignment formed on the sheet. , The conductor patterns of each part of the coil are accurately aligned. This is because the relative positional relationship between the conductor patterns for each part of the coil and the alignment conductor pattern is maintained constant, and by arranging the alignment conductor pattern at a predetermined position, The conductor patterns of the coil parts having a fixed positional relationship are accurately arranged at desired positions.

In the method of the present invention, for example, as shown in FIG. 1, the positioning conductor pattern is formed as a paired pattern of a ring-shaped positioning outer mark 4 and a small circular positioning inner mark 6, and a lower layer is formed. The inner mark 6 for alignment is used for alignment with the conductor pattern of each coil of the coil, and the outer mark 4 for alignment is used for alignment with the conductor pattern of each coil of the upper layer for easy and accurate alignment. be able to.

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 examples.

[0011]

EXAMPLE A ferrite slurry was prepared using Ni—Zn ferrite powder and a binder containing polyvinyl butyral as a main component, and the slurry was formed into a sheet by a doctor blade method to obtain a green sheet 1. Then, at a predetermined position of the obtained green sheet 1, a through hole 3 for connecting an internal conductor and a through hole 2 for positioning are provided.
Were simultaneously formed. On the other hand, an Ag paste obtained by kneading Ag powder, ethyl cellulose, α-terpineol and butyl carbitol acetate was used, and a peeling film 7 (see FIG. 3) was used. And / or the alignment inner mark 6 was printed.

Next, ten green sheets 1 having no through holes are laminated (see FIGS. 2 and 7).
(A)), on the uppermost layer, the conductor pattern 5 for each part of the coil
Then, the release film 7 on which the outer alignment mark 4 was printed was placed (FIG. 2), and these conductor patterns were transferred (FIGS. 3 and 7 (b)). Next, the green sheet 1 having the alignment through holes 2 and the connecting through holes 3 formed thereon was laminated on this sheet (FIG. 4).
And FIG. 7 (c)). At that time, the alignment was performed so that the outer circumference circle of the transferred ring-shaped alignment outer mark 4 was concentrically located within the circle of the alignment through hole 2.

Then, a release film 7 on which the conductor patterns 5, the ring-shaped outer positioning marks 4 and the small circular inner positioning marks 6 are printed is placed on this sheet (FIG. 5). Then, these conductor patterns were transferred (FIGS. 6 and 7 (d)). At that time, transfer was performed by aligning so that the inner alignment mark 6 was located at the center of the ring-shaped outer alignment mark 4 formed in the lower layer that was visible through the alignment through hole 2. Further, by this transfer, the outer mark 4 for the next alignment is formed near the through hole 2.

As described above, when the green sheets 1 are laminated,
The transfer of the conductor pattern 5, the outer mark 4 for alignment, and the inner mark 6 for alignment of the coil is alternately repeated, and finally, 10 layers of the green sheet 1 without through holes are laminated, A laminated body as shown in was prepared. Next, the produced laminated body was pressure-bonded, debindered, and then fired at a temperature of 900 ° C. in the atmosphere to form an external electrode to obtain a laminated ceramic inductor.

[0015]

As a result of the development of the method of the present invention, the positioning accuracy of the conductor pattern of each part of the coil is improved. Therefore, the variation in the inductance value of the manufactured monolithic ceramic inductor is reduced, and the quality is improved. Further, the alignment step in the method of the present invention can be carried out extremely easily as compared with the conventional method, so that the workability is remarkably improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a developed state of a laminated body produced by the method of the present invention.

FIG. 2 is a diagram showing stepwise a manufacturing process of a laminate in the method of the present invention, showing a sheet and a release film when transferring the conductor pattern of each part of the coil and the conductor pattern for alignment onto a green sheet. It is a perspective view.

FIG. 3 is a diagram showing stepwise a manufacturing process of a laminate in the method of the present invention, and is a perspective view showing a state in which the release film on the green sheet is peeled off.

FIG. 4 is a diagram showing stepwise a manufacturing process of a laminated body in the method of the present invention, which is a perspective view showing a state in which a through-hole forming green sheet is laminated on a sheet.

5A to 5C are diagrams showing step by step a manufacturing process of a laminated body in the method of the present invention, which is a sheet and a release film when transferring the conductor pattern of each part of the coil and the conductor pattern for alignment onto the green sheet of FIG. It is the perspective view which showed.

FIG. 6 is a diagram showing stepwise a manufacturing process of a laminate in the method of the present invention, and is a perspective view showing a state where the release film on the green sheet is peeled off.

FIG. 7 is a diagram showing stepwise a manufacturing process of a laminated body in the method of the present invention, which is an enlarged plan view of a peripheral portion of a through hole for alignment.

FIG. 8 is a view showing a manufacturing process of a laminate by a conventional method,
It is a top view explaining the alignment method.

[Explanation of symbols]

 1 ... Green sheet 2 ... Positioning through hole 3 ... Internal conductor connecting through hole 4 ... External positioning mark 5 ... Coil conductor pattern 6 ... Internal positioning Mark 7 Peeling film

Claims (1)

[Claims] 1. A step of transferring and forming a conductor pattern for each coil portion, which becomes a spiral coil by stacking through holes, on a magnetic ceramic green sheet in which through holes for connecting internal conductors are formed, and after forming the patterns. The steps of laminating the magnetic ceramic green sheets having the through holes for connection formed on the sheet are alternately repeated to form a laminated body, and the laminated body is pressure-bonded and then fired to form external electrodes. In the method of manufacturing a ceramic inductor, a positioning through hole is formed in a part of the periphery of a green sheet when the connecting through hole is formed, and a conductor pattern for each coil portion is formed on the sheet where the connecting through hole is formed. When transferring and forming on a ring, a ring-shaped outer pattern and a small circle-shaped inner pattern placed close to each other And a pair of positioning conductor patterns each of which is formed on the peripheral portion of the green sheet at the same time as the conductor patterns of the coil are transferred and formed. The outer conductor pattern formed on the green sheet is superposed on the center portion of the through hole for alignment of the green sheet so as to be seen, and the conductor for alignment is transferred and formed simultaneously with the conductor pattern of each coil on the green sheet. In the pattern, the inner mark is transferred to the central portion of the ring-shaped outer mark on the green sheet one layer below, and the outer mark to be the next mark is transferred to a predetermined position on the green sheet in the vicinity thereof. A method for manufacturing a monolithic ceramic inductor, comprising: