JPH04791A - Manufacture of laminated chip inductor - Google Patents

Abstract

PURPOSE:To reduce a manufacturing cost by so regulating the relative positions of a mold and a green sheet that the symmetrical center line of two different types of through hole patterns is disposed at the same positions even if one green sheet is inverted rightside left, and manufacturing a green sheet piece having two types of through hole patterns by one mold. CONSTITUTION:A square green sheet piece is set in a perforating mold, and a through hole pattern (a) is opened. The piece is inverted rightside left with a symmetrical center line 8 of the piece surrounded by contacts 9 of a mold at the four corners as a reference, thereby obtaining a through hole according to the through hole pattern (b). Conductor paste is printed on the pieces having the patterns (a), (b), thereby obtaining the pieces (A), (C), (B). Conductor paste is printed on the piece in which a through hole is not opened to obtain a sheet piece (D). These pieces are laminated, thermally press-bonded, and cut to chip shapes by a cutter.

Description

[Detailed description of the invention] [Industrial application fields] 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.

■The crimped laminate is cut, separated into chips, and fired.

■The product is made by baking external electrodes onto the fired chip.

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 conductive fill on the sheet, and the upper three layers and lower two layers of the laminated green sheet pieces have through holes and printing. It has not been.

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.

Figure 4 shows the positions of through holes 2 (C), (D), (E), (F) and the printing of conductor coil 3 when the coil pattern is 3/4 turn for each layer of green sheet piece 1. Pattern (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 green sheet layer. In the case of 3/4 turn per layer, it is necessary to prepare two types, and in the case of 3/4 turns per layer, four types have to be prepared, and there is a problem that an increase in manufacturing costs due to purchasing a large number of expensive molds is unavoidable.

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 reducing the number of molds, which is a factor in increasing manufacturing costs, by half.

[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, and created a green with through holes drilled therein. By flipping the sheet inside out,
They discovered that two types of through-hole patterns can be obtained with one mold by adjusting the relative position of the mold and green sheet so that the through-holes are aligned with the positions of other through-hole patterns. We have arrived at the present invention.

Therefore, the present invention provides a method for forming through holes in predetermined positions of a green sheet mainly composed of magnetic material or insulating ceramic, and forming the green sheet in such a way that the conductor coil pattern formed on the green sheet is connected through the through hole. In the manufacturing method of a multilayer chip inductor, which comprises stacking, thermocompression bonding, integrating, separating into chip shapes, and then baking external electrodes on the fired body, the above-mentioned through hole is located in a mold. A means for moving and adjusting is provided so that the center lines of symmetry of the two different types of through hole patterns formed on the green sheet are at the same position even when one of the green sheets is turned over and the left and right sides are reversed. By adjusting the relative position of the mold and the green sheet, one mold can be made into two
The present invention provides a method for manufacturing a multilayer chip inductor, which is characterized by manufacturing green sheet pieces having various types of through-hole patterns.

In the method of the present invention, when a green sheet piece that has been perforated according to one through-hole pattern is turned over and reversed from side to side, it is set so that it will come to the position of the through-hole or the position of the other pattern. Therefore, two types of through hole patterns can be obtained with one mold.

FIG. 1 shows an example of an embodiment of the present invention, and as seen in the plan view of FIG. In the green sheet piece 1 in which a through-hole pattern 2a according to the hole pattern (a) has been perforated, a symmetry center line 8 indicated by a dotted line equidistant from both sides is determined, and the left and right sides of the sheet are determined based on this line. By reversing, two types of through-hole patterns are obtained, and their relative positions are shown in the same figure (1).
In the plan view, as shown by 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 FIG. 2).

Similarly, as seen in the plan view of FIG. 1 (3) and the side view of FIG. The same effect can be obtained even if the metal frame is determined from the positioning hole 11 that is inserted into the positioning pin 12 provided in the positioning hole 11, and the entire metal frame is reversed from side to side with respect to this center line of symmetry.

Further, FIG. 1(4) shows a through-hole pattern 2c (through-hole pattern (c) in FIG. 4) bored in the green sheet piece 1 and a center line of symmetry 8 set on the sheet.
Through-hole pattern 2d obtained when the sheet is turned over and left and right (pattern (to) in Figure 4)
), and similarly, the relative position with (5) in the same figure is shown.
4 shows the relative positions of through-hole patterns 2e (through-hole pattern (d) in FIG. 4) and 2f (through-hole pattern (e) in FIG. 4).

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

[Example 1] N containing Fe2O3, ZnO, Ni01CuO as main components
Using polyvinyl butyral as a binder for i-Zn-Cu ferrite powder, a long green sheet with a thickness of 100 μm was prepared by a doctor blade method. This was cut into a predetermined size to obtain a rectangular green sheet piece.

Set the rectangular green sheet piece in the 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 position of the through hole is determined by reversing the left and right sides of the green sheet piece with reference to the center line 8 of symmetry in the green sheet piece whose four corners are surrounded by the butts 9 of the mold. However, another pattern, that is, a through hole pattern according to the through hole pattern (b) shown in FIG. 2 was obtained.

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 Figure 3(a), and heated at 100°C and 300kg/cm2
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 10 as shown in FIG. The center line of symmetry 8 of the green sheet is determined from the positioning holes provided at the four corners, and after first drilling the through hole pattern 2a of (a) above, the center line of symmetry 8 is used as a reference for each metal frame. By reversing the left and right sides, the above-mentioned (b) through-hole pattern 2b was obtained.

Next, a conductive paste was printed in the same manner as in Example 1,
A multilayer chip inductor was obtained by punching out the hole using the positioning hole as a reference and using the same method 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. 1 (4), as shown in Fig. 4 (c)
The through-hole pattern (to) should be arranged so that the center line of symmetry 8 coincides with a line equidistant from the left and right sides of the green sheet piece 1, and as shown in FIG. 1 (5). The center line 8 of symmetry between the through-hole pattern in ) and the through-hole pattern in (e) is the green sheet piece 1.
The two drilling dies were each adjusted so that they coincided with lines equidistant from the left and right sides of the.

By this method, two types of through-hole patterns can be obtained using two molds, and by reversing the left and right patterns with respect to the center line of symmetry, (1) (2), (2),
(E) Green sheet pieces having 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 (1) using the through-hole pattern of (e) above, and one with the printed pattern (G) and (1) 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 molds that were conventionally required can be halved, and the number of expensive molds can be reduced. This has the effect of enabling cost reduction.

[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 FIG. The relative position of two types of patterns is also determined by the through-hole pattern formed on the green sheet piece and the through-hole pattern obtained by reversing the left and right sides of the green sheet piece using the symmetry center line set on the green sheet piece. Figure (2) is a plan view for finding the center line of symmetry of a green sheet piece whose four corners are surrounded by mold fittings, Figure (3) and (3') are a plan view of the metal frame. FIG. 2 is a plan view and a side view showing a case where a center line of symmetry is determined in a green sheet pasted on a green sheet. Figure 2 shows through-hole patterns (A) and (B) and conductor coil printed patterns (A) and (B) when the coil pattern has 172 turns 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), (d), (e), (f) and conductor coil printed patterns (c) when the coil pattern is 3 ha turns per green sheet layer.
It is a top view which shows 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 (f) (black circle) 2e...Through hole pattern (d) (white circle) 2f...Through hole pattern (e) (black circle) 3...Conductor coil 4... ... Laminated body 5 ... Chip 6 ... Sintered body 7 ... External electrode 8 ... Center line of symmetry of green sheet piece 9 ...
...The bottle holder is the mold stopper 10...Metal frame 11...Positioning hole 12...Positioning pin

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 comprises integrating the multilayered chip inductor into a chip, separating it into chip shapes, and then baking an external electrode on the fired body, the method moves and adjusts the position of the mold for drilling the through hole. The mold and green are placed so that the center line of symmetry of the two different types of through-hole patterns formed on the green sheet is in the same position even when one of the green sheets is turned over and the left and right sides are reversed. A method for manufacturing a multilayer chip inductor, characterized in that a green sheet piece having two types of through-hole patterns is manufactured using one mold by adjusting the relative position with respect to the sheet.