JPH11176685A - Manufacture of inductance element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductance element which can get high inductance and Q, keeping property of a magnetic material of a ferrite core. SOLUTION: A conductor film is made at the flank of a columnar or prismatic ferrite core, and this conductor film is cut by laser to form a spiral conductor pattern. A glass layer 11 is made in advance between a conductor film 12 and a ferrite core 10, and it is so arranged that only the surfaces of the conductor film and the glass layer are cut when cutting it by laser. The magnetic material of the ferrite core 10 does not degenerate since it is not directly irradiated with laser, so it can keep the property of the magnetic material.

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 an inductance element, and more particularly to a method for improving the characteristics of an inductance element of a type in which a conductor pattern for forming a coil of a conductor film is formed around a ferrite core. It is.

[0002]

2. Description of the Related Art In general, an inductance element in which a conductive wire is wound around a ferrite core has been used. However, due to advances in processing techniques, a structure in which a conductor film is formed instead of a winding has been put to practical use. . In particular, with the advance of laser processing technology, highly accurate conductor patterns can be obtained, and those suitable as chip inductors for medium and high frequencies can be obtained.

[0003] This type of inductance element is shown in FIG.
As shown in FIG. 5, a spiral conductive pattern 22 is formed around a ferrite core 20, and a terminal electrode 24 is formed. When manufacturing, a conductive film is formed by forming an Ag layer on the entire side surface of the ferrite core by electroless plating and electrolytic plating, and this conductive film is cut to expose the ferrite body, and a spiral conductive pattern is formed. It is common to leave

[0004] In order to cut the conductive film, a method of irradiating a laser beam instead of a cutter to remove the conductive film has been adopted. As a result, the conductor pattern can be formed accurately.

[0005]

However, in the case of laser processing, the ferrite core body is also heated by laser irradiation. Due to this heating, the properties of the surface of the ferrite core change, and a problem arises in that the oxide having a high insulating property turns into a conductor. As a result, the inductance, Q, etc. of the inductance element deteriorate. Further, the adhesion between the silver electrode and the ferrite core is not sufficient, and there is a problem in reliability. The present invention is to prevent deterioration of the ferrite characteristics and obtain an inductance element having good characteristics.

[0006]

The present invention solves the above-mentioned problems by forming a glass layer between a conductor film and a ferrite core and stopping the cutting depth to the glass.

That is, a conductor film is formed on a side surface of a prismatic or cylindrical ferrite core, and a part of the conductor film is cut by laser processing to form a spiral conductor pattern around the ferrite core. In the manufacturing method, a ferrite core is formed by forming a glass layer on the surface of the ferrite core where a spiral conductor pattern is formed, forming a conductive film on the glass layer, and cutting a part of the conductive film by laser processing. Is characterized in that a spiral conductor pattern is formed around the periphery.

[0008]

FIG. 2 shows a process of a method for manufacturing an inductance element according to the present invention. Ni-Zn or Ni-
A Cu-Zn ferrite is formed into a predetermined shape and fired to obtain a ferrite core. A glass layer is formed on a portion of the ferrite core where a spiral conductive pattern is to be formed. A base electrode layer of a nickel alloy or the like is formed on the side surface of the ferrite core, and a conductive film of silver or the like is formed thereon. This conductor film is cut in a predetermined pattern while scanning with a laser beam, leaving a conductor film of a predetermined pattern.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a material for an inductance element for medium and high frequencies such as for communication equipment, a ferrite of Ni-Zn or Ni-Cu-Zn is used. Oxides of these materials and Fe ₂ O ₃
A material obtained by mixing the above components in a predetermined amount is molded and fired to obtain a ferrite core. Generally, the cores of the above systems have a high resistivity. A glass paste is applied to the side surface of the ferrite core on which the spiral conductive pattern is to be formed, and is baked to form a glass layer.

[0010] The ferrite core provided with this glass layer,
A conductive film such as nickel or a nickel alloy is formed by electroless plating. A silver conductor layer is further formed on the surface by electrolytic plating. As a material of the conductor film, copper can be used in addition, and different metals may be formed in multiple layers.

[0011] The conductor film formed on the ferrite core is cut by laser processing. The conductor film is burned off by the laser beam, and a part of the surface of the underlying glass is burned off together with the conductor film. However, since the glass layer is interposed, the ferrite core is not irradiated with the laser and cut.

FIG. 1 is a front sectional view of an inductance element manufactured according to the present invention. A glass layer 11 is formed on a part of the ferrite core 10, a nickel layer 12 is formed thereon as a base layer, and a silver layer 13 is formed thereon as a conductor layer. The surface portions of the silver layer 13, the nickel layer 12, and the glass layer 11 are cut by a laser to leave a spiral conductor pattern.

Although the terminal electrode 14 for connecting the conductor pattern of the ferrite core treated as described above to an external circuit is formed, the metal film formed first can be used as a base electrode as it is. It is preferable to apply nickel or solder plating to the terminal electrode portion to prevent solder erosion. Further, it is desirable to form a protective film with a resin or the like on the surface of the conductor pattern formed on the side surface of the ferrite core.

The present invention is not limited to the above example, but can be applied to all inductance elements in which a conductor film is formed on a ferrite core to obtain a predetermined conductor pattern by laser processing.

[0015]

According to the present invention, deterioration of the characteristics of the ferrite core can be prevented, so that an inductance element having high inductance and Q and excellent characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an inductance element obtained according to the present invention.

FIG. 2 is an explanatory view of the process of the present invention.

FIG. 3 is a front view of an inductance element.

[Explanation of symbols]

 10: Ferrite core 11: Glass layer 12: 13: Conductive layer

Claims (3)

[Claims] 1. An inductance element comprising: a conductor film formed on a side surface of a prismatic or cylindrical ferrite core; and a part of the conductor film being cut by laser processing to form a spiral conductor pattern around the ferrite core. In the manufacturing method, a ferrite core is formed by forming a glass layer on the surface of the ferrite core where a spiral conductor pattern is formed, forming a conductive film on the glass layer, and cutting a part of the conductive film by laser processing. Forming a spiral conductor pattern around the periphery of the substrate. 2. An inductance element comprising: a conductor film formed on a side surface of a prismatic or cylindrical ferrite core; and a part of the conductor film is cut by laser processing to form a spiral conductor pattern around the ferrite core. In the manufacturing method, a glass layer is formed on the surface of the ferrite core where a spiral conductive pattern is formed, a base electrode layer is formed on the glass layer by electroless plating, and a conductive film is formed on the surface by electrolytic plating. To form a two-layer conductor film,
A method for manufacturing an inductance element, wherein a part of a conductive film is cut by laser processing to form a spiral conductive pattern around a ferrite core. 3. The method for manufacturing an inductance element according to claim 1, wherein the cutting depth is smaller than the total thickness of the conductive film and the glass layer.