JPH04790A - Manufacture of laminated chip inductor - Google Patents

Abstract

PURPOSE:To reduce the number of molds by half and to reduce a manufacturing cost by rotating a green sheet at 180 degrees at the symmetrical center of two different types of through hole patterns as a rotating central point, and manufacturing a green sheet piece having two types of through hole patterns by one mold. CONSTITUTION:Since a green sheet piece opened according to one through hole pattern by a perforating mold is rotated at 180 degrees at its central point as a rotating central point to so set as bring the position of a through hole to the position of the other pattern, two types of through hole patterns can be obtained by one mold. Four corners are surrounded by the contacts 9 of the mold, the center 8 of the piece 1 opened with a through hole pattern 2a is obtained at the intersection of diagonal lines of the piece, rotated at 180 degrees with the center 8 as the rotating central point to obtain the pattern 2a indicated by white circles and the pattern 2b indicated by black solid circles.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a multilayer chip inductor.

[Prior Art] A multilayer chip inductor is an integrated chip-shaped inductor in which a conductor forming a coil is built into a magnetic material or insulating ceramic.

A general method for manufacturing this multilayer chip inductor is as follows.

■Make a green sheet consisting of magnetic ceramic powder and organic binder.

(Drill through-holes at predetermined positions on the green sheet.

■ Form a coil pattern on the green sheet using conductive paste.

2) Laminate the green sheets so that the coil patterns are connected between the layers through through holes, and heat and press them together to integrate them.

6) Cut the crimped laminate and separate each chip,
Fire.

(6) Baking external electrodes onto the fired chip to produce a product.

Figure 2 shows the positions (a) and (b) of the through holes 2 and the printed pattern of the conductor coil 3 (
It is a top view which shows A), (B), (C), and (D).

FIG. 3 is a perspective view showing a simple manufacturing process of a multilayer chip inductor using the green sheets shown in FIG.
Figure (a') shows the respective patterns of through holes 2 and conductor coils 3 on the sheet, and the upper three layers and lower two layers of the laminated green sheet pieces have through holes and printing. Not applied.

Figures (b) to (e) respectively show a stack 4 of green sheets, a chip 5 cut from the stack, a fired chip 6, and a stacked chip inductor to which external electrodes 7 are attached.

FIG. 4 shows the positions (C), (D), (E), (F) of the through holes 2 and the printed pattern of the conductor coil 3 (FIG. 4) when the coil pattern is 374 turns for each layer of the green sheet piece 1. E), (F), (G), (H), (1),
It is a top view showing (J).

FIG. 5 is a perspective view showing a simple manufacturing process of a multilayer chip inductor using the green sheets shown in FIG.
Figure (a') shows the respective patterns of through holes 2 and conductor coils on the sheet;
As shown in the figure, the upper 3 layers and the lower 2 layers of the laminated green sheet pieces
The layers do not have through holes or printing, and the subsequent figures are the same as in FIG. 3.

[Problems to be Solved by the Invention] However, in the conventional manufacturing method of multilayer chip inductors, the mold required for punching through holes in the green sheet is limited to 1/2 turn per layer of the green sheet. In the case of 3/4 turns per layer, it is necessary to prepare two types, and four types in the case of 3/4 turns per layer.Moreover, these molds with pins tend to break or bend, lacking durability, and must be replaced frequently. If multiple molds are not prepared at all times, productivity will be hindered, and there is an unavoidable increase in manufacturing costs due to purchasing a large number of expensive molds.

Therefore, an object of the present invention is to provide a method for manufacturing a multilayer chip inductor that can contribute to reducing manufacturing costs by halving the number of molds, which is a factor in increasing manufacturing costs.

[Means and effects for solving the problem] As a result of research to achieve the above object, the present inventors focused on the fact that the positions of the through holes are lined up at equal intervals. If you rotate a green sheet with a through-hole pattern 180 degrees around the appropriate position so that the through-hole position is aligned with the other pattern, you can create two types of through-holes in one mold. It was discovered that a pattern could be obtained, and the present invention was achieved.

Accordingly, the present invention involves drilling through holes at predetermined positions in a green sheet mainly composed of magnetic material or insulating ceramic, and forming the green sheet in such a way that the conductive coil pattern formed on the green sheet is connected through the through hole. In the manufacturing method of a multilayer chip inductor, which consists of laminating, thermocompression bonding, and then separating into chip shapes, and then baking external electrodes on the fired body, the green sheets are formed using a hole-punching mold. By rotating the green sheet 180 degrees using the center of symmetry of the two different types of through hole patterns to be formed as the center of rotation, a green sheet piece having two types of through hole patterns is produced using one mold. The present invention provides a method for manufacturing a multilayer chip inductor characterized by the following.

In the method of the present invention, a piece of green sheet that has been perforated according to one through-hole pattern with a punching die is rotated 180 degrees about its center point as a rotation center point, so that the positions of the through-holes are changed to the positions of the other pattern. Since it is set so that two types of through-hole patterns can be obtained with one mold.

FIG. 1 shows an example of an embodiment of the present invention, in which the four corners are surrounded by mold stoppers 9 as seen in the plan view of FIG. The center 8 of the green sheet piece 1 in which the through-hole pattern 2a according to the hole pattern (a) is perforated is found at the intersection of the diagonal lines of the sheet piece, and the center 8 is rotated 180 degrees using this center as the rotation center point. The plan view of Figure (1) shows a through-hole pattern 2a indicated by a white circle and a through-hole pattern 2b indicated by a black circle (through-hole pattern (b) in Figure 2).
The relative position is shown.

Similarly, in the plan view of FIG. 3 (3) and the side view of FIG. The same effect can be obtained by rotating the entire metal frame 180 degrees around this point.

In addition, in the same figure (4), 2 obtained by rotating the green sheet piece by 180 degrees with the center 8 of the green sheet piece as the rotation center point.
The relative positions of the different types of through-hole patterns 2C (through-hole pattern (c) in FIG. 4) and 2d (through-hole pattern (e) in FIG. 4) are shown, and similarly (5) in the same figure. 4 shows the relative positions of through-hole pattern 2e (through-hole pattern (d) in FIG. 4) and 2f (through-hole pattern (f) in FIG. 4).

The present invention will be further explained below with reference to Examples.

[Example 1] N containing Fe203, ZnO, N1pSCuO as main components
A long green sheet with a thickness of 100 IIR was prepared by using a polyvinyl butyral resin as a binder for i-Zn-Cu ferrite powder using a doctor blade method.

This was cut into a predetermined size to obtain a rectangular green sheet piece.

Set this rectangular green sheet piece in a punching mold,
Through holes were bored at predetermined positions, that is, according to the through hole pattern (a) shown in FIG. Next, as shown in FIG. 1 (2), the center 8 of the green sheet piece whose four corners are surrounded by the mold abutments 9 is found at the intersection of the diagonal lines of the sheet piece, and this center 8 is set as the center of rotation. as 180
By rotating the axis, the position of the through hole can be changed to another pattern, that is, the through hole pattern (b) shown in Figure 2.
A through-hole pattern was obtained according to the following.

Next, conductive paste was printed on the green sheet pieces with the through hole pattern of (a) above to obtain the green sheet pieces (A) and (C) shown in Figure 2, and the through hole pattern of (b) above was printed. A conductive paste was printed on a piece of green sheet with a hole in it to obtain the green sheet piece shown in Figure (B), and a conductive paste was printed on a piece of green sheet without through holes to obtain the green sheet piece shown in Figure (D). In addition to obtaining sheet pieces, green sheet pieces on which no conductive paste was printed and no through-hole pattern was formed were prepared.

Next, these green sheet pieces were stacked as shown in Fig. 3(a), and heated at 100°C and 300kg/cm2 pressure.
After thermocompression bonding was carried out to form a laminate as shown in FIG. 6(b), it was cut into individual chips using a cutting machine.

This was fired at 900° C. for 1 hour to obtain a chip-shaped sintered body. Furthermore, an external electrode containing Ag as a main component was coated on this sintered body and baked at 800° C. to obtain a multilayer chip inductor.

[Example 2] After obtaining a rectangular green sheet piece 1 in the same manner as in Example 1, the green sheet piece 1 is attached to a metal frame 1o as shown in FIG. The position of the positioning pin 12 of the mold was set so that the position of the center of symmetry of the positioning hole coincided with the position of the center of symmetry of the through-hole pattern 2a in (a) and the through-hole pattern 2b in (b). .

Two types of through-hole patterns (a) and (b) were obtained by rotating the green sheet piece 1 stretched over the metal frame 1o obtained in this way by 180 degrees together with the metal frame.

Next, a conductive paste was printed in the same manner as in Example 1,
Through holes were formed using a mold using the positioning hole 11 as a reference, and a multilayer chip inductor was obtained in the same manner as in Example 1.

[Example 3] After obtaining a rectangular green sheet piece 1 in the same manner as in Example 1, as shown in FIG.
The center of symmetry between the through-hole pattern in (e) and the through-hole pattern in (e) coincides with the center of the outer shape of the green sheet piece 1, that is, the center point 8.
) As shown in FIG. were adjusted respectively.

With this method, two types of through-hole patterns can be obtained using two molds, and by rotating these molds 180 degrees, the patterns shown in FIG. 4 (C), (D), (E), (
Green sheet pieces with four types of through-hole patterns were obtained.

Next, a conductor paste was printed on the green sheet piece having the through-hole pattern (C) above to obtain a green sheet piece having the printed conductor coil pattern (E) shown in FIG. 4. Similarly, one with the printed pattern (F) using the through-hole pattern of (d) above, one with the printed pattern (G) and (I) using the through-hole pattern of (e) above, and one with the printed pattern (G) and (I) using the through-hole pattern of (e) above. ) was used to obtain a green sheet piece with a printed pattern (H), and a green sheet piece with no through holes was used to obtain a green sheet piece with a printed pattern (J).

Next, these green sheet pieces were laminated as shown in FIG. 5(a), and a laminated chip inductor was manufactured in the same manner as in Example 1.

[Effects of the Invention] As explained above, by manufacturing a laminated inductor according to the method of the present invention, the number of punching dies that were conventionally required can be halved, and the number of expensive dies can be reduced. This has the effect of reducing costs.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the method of drilling a through-hole pattern adopted in each embodiment of the manufacturing method of the present invention, and (1), (4), and (5) in the same figure are all A plan view showing the relative positions of two types of through-hole patterns obtained by rotating the green sheet piece 180 degrees around the center of the rotation center. 3 is a plan view showing a case where the center of a green sheet piece attached to a metal frame is found, and FIG. Figure 2 shows through-hole patterns (A) and (B) and conductor coil printed patterns (A) and (B) when the coil pattern is 1/2 turn per green sheet layer.
), (C), and (D) are plan views. FIG. 3 is a perspective view showing a simple manufacturing process of a multilayer chip inductor using green sheets having the patterns shown in FIG. 2. FIG. Figure 4 shows through-hole patterns (c) and (c) when the coil pattern is 3/4 turn for each green sheet layer.
FIG. 4 is a plan view showing conductor coil printed patterns (E), (F), (G), (H), (I), and (J). FIG. 5 is a perspective view showing a simple manufacturing process of a multilayer chip inductor using green sheets having the patterns shown in FIG. 4. FIG. Explanation of symbols 1...Green sheet piece 2...Through hole 2a...Through hole pattern (A) (white circle) 2b
...Through hole pattern (b) (black circle) 2C...
...Through hole pattern (c) (white circle) 2d...
Through-hole pattern (e) (black circle) 2e... Through-hole pattern (d) (white circle) 2f-... Through-hole pattern (f) (black circle) 3... Conductor coil 4... ... Laminated body 5 ... Chip 6 ... Fired body 7 ... External electrode 8 ... Center point 9 of green sheet piece ...
・Pin receiver mold attachment 10...Metal frame 11...Positioning hole 12...Positioning pin patent applicant Taiyo Yuden Co., Ltd. Agent Patent attorney Maruoka Masahiko's condolence figure 1...Clean route 2...Through 6\-rule 3...Isobody coil diagram Figure

Claims (1)

[Claims] Through-holes are punched at predetermined positions in green sheets mainly made of magnetic material or insulating ceramics, and the green sheets are stacked so that the conductor coil pattern formed on the green sheets is connected through the through-holes, and then thermocompression bonded. In the manufacturing method of a multilayer chip inductor, which consists of integrating the green sheets, separating them into chip shapes, and then baking external electrodes on the fired body, two different parts are formed on the green sheet using a punching die. By rotating the green sheet 180 degrees with the center of symmetry of each type of through-hole pattern as the rotation center point,
A method for producing a multilayer chip inductor, which comprises producing green sheet pieces having two types of through-hole patterns using one mold.