JPH0611015B2 - Chip coil manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a chip coil.

In recent years, along with the development of semiconductor elements, the coil is being made into a chip because of the demand for miniaturization and high integration of electronic devices and circuits. This chip coil is roughly classified into a wire wound type and a laminated type. A wire-wound chip coil has good characteristics such as Q, but has a difficulty in handling because the wire is exposed. In order to solve this drawback, a resin-molded product is commercially available, but the cost is significantly high. On the other hand, the laminated chip coil is manufactured by alternately printing a paste made of a magnetic material and an electrode paste made of Ag, Pd, etc., and then sintering the paste, but the Q of the electrode chip is poor due to the high specific resistance of the electrode material. Also, the cost is high due to the use of precious metals.

An object of the present invention is to solve the above technical problems and to provide a method for manufacturing a chip coil having a high Q and a low cost.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 (a) to 1 (g) are plan views for explaining the manufacturing process of the chip coil of one embodiment of the present invention, and FIG. 2 is a sectional view of the completed chip coil. In the method of manufacturing the chip coil according to the present invention, first, the laminated bodies 1 to 7 of the insulating magnetic green sheets are prepared. In the laminates 2 to 6 among the laminates 1 to 7, the void layer forming portions 8 to 12 are formed by a combustible material such as carbon that is decomposed or expelled during firing or a paste composed of a combustible material and magnetic powder. It is formed by screen printing or the like. These void layer forming portions 8 to 12 become void layers by firing as described later. The void layer forming portion 8 of the laminated body 2 is exposed at the lower edge of the laminated body 2, reaches the upper portion, and extends parallel to the upper end of the laminated body 2. The portion 17 exposed at the lower edge serves as one terminal as described later. The void layer forming portion 9 of the laminated body 3 extends from the upper portion where the through hole 13 penetrating is formed to the lower portion and extends in parallel to the lower end. This through hole 13
When the laminated body 3 is placed on the laminated body 2, it is formed at a predetermined position facing the end of the void layer forming portion 8 of the laminated body 2. The void layer forming portion 10 of the laminated body 4 extends in parallel with the upper end and reaches the lower portion where the through hole 14 is further formed. The through hole 14 is formed at a predetermined position facing the end of the void layer forming portion 9 of the laminated body 3 when the laminated body 4 is placed on the laminated body 3. The void layer forming portion 11 of the laminated body 5 has a through hole 15 penetrating therethrough and is formed similarly to the laminated body 3. The void layer forming portion 12 of the stacked body 6 extends from the lower portion where the through hole 16 is formed to the upper portion, is exposed at the upper end, and extends in parallel. The portion 18 exposed at the upper end becomes the other terminal as described later. The through hole 16 is formed at a predetermined position facing the end of the void layer forming portion 11 of the laminated body 5 when the laminated body 6 is placed on the laminated body 5. Although FIG. 1 shows an example in which the laminated bodies 1 to 7 are prepared one by one, as another embodiment, a plurality of laminated bodies 2 to 6 may be printed and then cut to prepare. .

After preparing a plurality of laminated bodies 1 to 7 configured as described above, in the present invention, the laminated body 2 is placed on the laminated body 1,
Further, the laminate 3 is placed thereon, and the laminates 1 to 7 are sequentially laminated in this manner. In this laminated state, the void layer forming portion 8 of the laminate 2 is connected to the void layer forming portion 9 through the through hole 13 of the laminate 3, and similarly, the void layer forming portion 9 of the laminate 3 is Through hole 14 of laminated body 4
Through the gap layer forming portion 10. Thereafter, the void layer forming portion 12 of the laminated body 6 is connected in a coil shape in this manner.

In the above example, the laminated bodies 1 to 4 were prepared one by one,
It may be prepared by cutting a plurality of printed sheets. Further, the laminated bodies 1 to 4 and the void layer forming portions 8 to 12 may be sequentially formed by a printing method.

After stacking in this way, it is placed in a firing furnace and fired at a predetermined high temperature to form an integral sintered body. Void layer forming part 8 to 12
The paste of No. 2 is composed of a combustible material or a combustible material that is decomposed or expelled during firing as described above, and a magnetic substance powder. Therefore, the void layer forming portions 8 to 8 printed with the paste of the laminates 2 to 6 by firing. 12 is a void layer. This void layer is continuous in a coil shape through the through holes 13, 14, 15, 16.

Then, the porous external terminals 19 and 20 are formed by baking at the opposite ends where the portions 17 and 18 of the sintered body in which the continuous void layers are formed are present.

Next, the sintered body having the external terminals 19 and 20 formed on both ends thereof is dipped in a melting bath of a low melting point metal such as Pb, Sn, or an alloy thereof, and pressurized. As a result, the molten metal is filled through the porous external terminals 19 and 20. After that, it is taken out of the melting tank and naturally cooled to form a continuous conductive portion in a coil shape as shown in FIG. As described above, in the method of manufacturing the chip coil according to the present invention, since the conductive portion continuous in a coil shape is formed of the low melting point metal, it is possible to obtain a chip coil having a low cost and a high Q.

Further, when the sintered body is taken out from the above-mentioned melting tank, the external terminals 19 and 20 serve as barriers when the molten metal flows out, so that a coil-shaped continuous conductive portion having no defect can be formed inside. .

Explaining the laminate 3, the void layer forming portion 9 may be formed in a U shape as shown in FIG. Although not shown, the void layer forming portion 10 of the laminated body 4 has an inverted U-shape.

As described above, according to the present invention, a void layer continuous in a coil shape is formed through firing through a through hole, and a low-melting-point metal in a molten state is press-fitted into the void layer and the through hole to continuously form a coil shape. Since the conductive portion is formed, it is possible to obtain a chip coil having low cost and high Q.

Further, when the sintered body is taken out of the melting tank after the molten metal is filled, the external terminal serves as a barrier when the molten metal flows out, and a continuous coil-shaped conductive portion having no defect can be formed inside. As a result, it becomes possible to manufacture a chip coil having no variation in inductance characteristics.

[Brief description of drawings]

1 (a) to 1 (g) are plan views for explaining a manufacturing process of an embodiment of the present invention, FIG. 2 is a sectional view of a completed chip coil, and FIG. 3 is another embodiment of the present invention. It is a top view of an example. 1-7 ... laminated body, 8-12 ... void layer formation part, 13-16
… Through holes.

Claims (1)

[Claims] 1. A plurality of insulating laminates having a void layer forming portion to be a void layer by firing and a through hole penetrating at a predetermined position at an end portion of the void layer forming portion are prepared, and each laminate is provided. The laminated body is laminated so that the void layer forming portion is continuous in a coil shape through the through hole, and the laminated laminate body is fired to form the void layer forming portion as a void layer, and is baked. Porous external terminals are formed at both ends of the united body, and the void layer and the through hole are filled with a low melting point metal in a molten state through the porous external terminals to form a continuous conductive portion in a coil shape. A method of manufacturing a chip coil, comprising: