TW201521055A - Method for manufacturing chip inductor - Google Patents

Abstract

A method for manufacturing chip inductor first prepares an iron core powder and presses the iron core powder into a frame-shaped powdered core. The pressed frame-shaped powdered core is sintered to form frame-shaped iron core and then an insulating layer is formed thereon. An electrode layer is formed on the insulating layer and then a coil is wrapped around the winding portion of the iron core to electrically connect the coil and the electrode layer. A close-magnet loop is formed by sealing glue on the winding portion and the electrode is exposed to complete the chip inductor.

Description

Chip inductor manufacturing method

The present invention relates to an inductor, and more particularly to a method of fabricating a chip inductor.

The inductor is a passive component, and has an electronic component that resists any current change. The inductor is composed of a core material wound around a coil, and the core material may be a magnetic material or a non-magnetic material. An inductor is a circuit component that is made up of a change in the current of a coil to produce a change in magnetic flux. The source of the magnetic field is that the charge is flowing, and it is formed by a current. The alternating current generates a magnetic field, and the changing magnetic field induces a current. The ratio of its linear relationship is called inductance.

The conventional combined inductor is mainly an I-shaped iron core having a Mn-Zn ferrite, the coil is wound around the I-shaped iron core, and the I-shaped iron core wound with the coil is assembled into one The cross section has a U-shaped cover to form a combined inductor. Since the combined inductor has a high magnetic permeability, a low saturation magnetic force, is easily saturated during use, and cannot withstand a large current, it has not been used.

Current inductors are required to withstand high currents, so most inductors such as chokes or chokes. The inductor is made by pressing powder, first winding an air-core coil, placing the air-core coil in the mold, pouring the iron powder into the mold and pressing the coil into an inductor, and the powder is pressed. The magnetic permeability is low and the saturation magnetic force is high. When used, the inductor is not easily saturated and can withstand a large current.

Another powder is pressed, and an air-core coil is first prepared in the production, the hollow coil is placed in the mold, and the iron powder added with the polymer material colloid is poured into the mold, and the force is 6-8 tons per square centimeter. Pressed by high pressure, the insulating paint on the coil is easily broken during the manufacturing process, resulting in a short circuit between the coil layer and the layer, resulting in a large current.

Another type of powder pressing is a hot-pressed ferrochrome powder (FeCrSi) which is first hot pressed into a convex shape, and the wound coil is placed on the protruding post of the base body, and then the iron chromium is formed by hot press forming technology. The crucible (FeCrSi) is pressed on the base body to cover the coil and the stud of the base body, and only the bottom of the seat body is exposed. The manufacturing method of the inductor is easy to cause leakage current.

Another type of powder pressing is to first make an air-core coil and a lead frame, and place the air-core coil and the lead frame in the mold, and then pour the iron powder into the mold first, and then heat-press, That is, the fabrication of the inductor is completed. Since such inductors have many components, they are relatively expensive to process and man-hours.

Therefore, the main object of the present invention is to solve the above-mentioned deficiencies. The present invention proposes to fabricate a wafer inductor by means of a thermosetting and sintering hybrid method, so that the inductor has high current resistance and high heat resistance.

Another object of the present invention is that after the inductor is fabricated, the coil is wrapped in the closed magnetic circuit structure to avoid leakage current.

To achieve the above objective, the present invention provides a method of fabricating a chip inductor, comprising:

An iron core powder is provided;

Pressing the iron core powder into a Japanese powder core;

The pressed Japanese-shaped powder core is sintered to form the Japanese-shaped powder core into a Japanese-shaped iron core;

After the iron core is fired, an insulating layer is formed on the surface of the iron core;

Forming an electrode layer on the surface of the insulating layer;

Winding a coil on the winding portion of the iron core, the coil is electrically connected to the electrode layer; and

The coil region is sealed to form a closed magnetic circuit structure. After the closed magnetic circuit structure is fabricated, the electrode layer is exposed to form a wafer type inductor.

Among them, the iron core powder is a ferrosilicon material (FeSi) or a soft magnetic material of iron nickel 50 powder (FeNi50) as a material.

Among them, the iron core powder is pressed into a Japanese-shaped powder core by a thermosetting process.

Among them, the Japanese-shaped powder core is formed into a Japanese-shaped iron core by low-temperature sintering.

The iron core has a frame body, and the frame body has a winding portion, and the winding portion and the frame body have two through grooves.

Among them, the iron core has a magnetic permeability μ=60 by a sintering technique.

Wherein, the insulating layer is an insulating varnish.

Wherein, the electrode layer is printed by printing a layer of copper, and then plating a silver layer on the copper layer, or printing a silver layer, and then plating the tin on the silver layer to form an electrode layer.

Wherein, the coil has a two-wire head, and the two-wire head is electrically connected to the electrode layer.

Wherein, the coil is a flat bare copper wire.

Wherein, the magnetic closed magnetic circuit structure is a magnetic glue.

The chip inductor has a copper loss of 0.67W.

The equivalent DC resistance of the chip inductor is 6.74mohm.

100~114‧‧‧Steps

1‧‧‧ iron core

11‧‧‧ frame

12‧‧‧ winding department

13‧‧‧through slot

2‧‧‧Insulation

3‧‧‧electrode layer

4‧‧‧ coil

41‧‧‧ thread head

5‧‧‧Closed magnetic circuit structure

The first figure is a schematic diagram of the fabrication process of the wafer inductor of the present invention.

The second figure is a schematic view of the core structure of the chip inductor of the present invention.

The third figure is a schematic view showing the formation of an insulating layer on the core of the chip inductor of the present invention.

The fourth figure is a schematic view showing the fabrication of an electrode layer on the insulating layer of the wafer inductor of the present invention.

Fig. 5 is a schematic view showing a winding of a core of a chip inductor of the present invention.

Figure 6 is a cross-sectional, cross-sectional view taken at line 6-6 of the fifth figure.

The seventh figure is a package schematic diagram of the wafer inductor of the present invention.

Figure 8 is a cross-sectional, cross-sectional view taken at 8-8 of the seventh diagram.

The technical content and detailed description of the present invention are now described as follows:

Please refer to the first to seventh figures, which are schematic diagrams for the fabrication process and structure of the wafer inductor of the present invention. As shown in the figure, in the method for fabricating the chip inductor of the present invention, first, as in step 100, an iron core powder is prepared, which is an iron-iron powder material (FeSi) or a soft magnetic material of iron-nickel 50 powder (FeNi50). ).

In step 102, in the thermosetting process, the iron core powder is pressed into a "day" shaped powder core by a thermosetting process (as shown in the second figure).

Step 104, sintering, and sintering the pressed "day" shaped powder core, and after sintering at a low temperature, forming the "day" shaped powder core into a "day" shaped iron core (powder sintered body) 1 The iron core 1 has a frame body 11 having a winding portion 12 therein. The winding portion and the frame body 11 have two through grooves 13 extending through the iron core 1 (as shown in the second figure). In the present figure, the core 1 utilizes a sintering technique to make the magnetic permeability μ = 60.

In step 106, an insulating layer is formed. After the sintered iron core 1 is sintered, an insulating layer 2 is formed on the surface of the iron core 1 (as shown in the third figure). In the figure, the insulating layer 2 is an insulating varnish.

In step 108, an electrode layer is formed. After the insulating layer 2 on the surface of the core 1 is completed, a layer of copper is printed by using printing technology, and then a silver layer is plated on the copper layer, or after printing a silver layer, and then on the silver layer. A method of electroplating tin is to form an electrode layer 3 at a predetermined position on the surface of the insulating layer 2 (as shown in the fourth figure).

Step 110, a copper wire is prepared, and the copper wire is wound on the winding portion 12 of the iron core 1 through the two through grooves 13 to form a coil 4, and the two ends of the coil 4 are wound with a wire head 41. (as shown in the fifth figure). In this figure, the coil is a flat bare copper wire.

In step 112, the electrode layer is connected. After the coil 4 is wound, the wire ends 41 of the two ends of the coil 4 are electrically connected to the electrode layer 3 (as shown in FIG. 6).

Step 114, the encapsulation is made, and the area of the coil 4 is covered with magnetic glue to form a closed magnetic circuit structure 5. After the closed magnetic circuit structure 5 is fabricated, the electrode layer 3 is exposed, and a chip inductor is also formed. (as shown in Figures 7 and 8). In the figure, the closed magnetic circuit structure 5 can avoid the occurrence of magnetic flux leakage.

The iron core 1 described above is sintered by iron-iron 50 powder (FeNi50) of iron ore powder or soft magnetic material so that the magnetic permeability μ = 60. Since the magnetic permeability is high, the number of turns of the coil 4 is small, the copper loss is 0.67 w, and the equivalent DC resistance DCR (DC Resistance) is 6.74 mohm, so the current is small, and the current withstand current is high and the heat resistance is high.

Please refer to the second to eighth figures, which are schematic diagrams of various viewing angles of the wafer inductor of the present invention. As shown in the figure, the wafer inductor structure of the present invention comprises: an iron core 1, an insulating layer 2, an electrode layer 3, a coil 4 and a closed magnetic circuit structure 5.

The iron core 1 has a frame 11 having a winding portion 12 therein. The winding portion 12 and the frame 11 have two through grooves 13 therebetween. In the present drawing, the iron core 1 has a zigzag shape, and a ferromagnetic powder material (FeSi) or a soft magnetic material of iron-nickel 50 powder (FeNi50) is used as a material, and a magnetic permeability μ=60 is obtained by a sintering technique.

The insulating layer 2 is coated on the outer surface of the core 1. In the figure, the insulating layer 2 is an insulating varnish.

The electrode layer 3 is disposed on the surface of the insulating layer 2 on the side of the iron core 1. The electrode layer 3 has a copper layer thereon, and a silver layer is disposed on the copper layer, or the electrode layer 3 is a silver layer. A tin layer is disposed on the silver layer.

The coil 4 is inserted through the two through slots 13 and wound around the winding portion 12, and has a two-wire head 41 electrically connected to the electrode layer 3. The coil 4 is a flat bare copper wire.

The closed magnetic circuit structure 5 is disposed on the coil 4 to cover the flat bare copper wire of the coil 4, and after the closed magnetic circuit structure 5 covers the coil 4, a chip inductor structure is formed (such as the seventh As shown in the figure, the wafer inductor structure can be adhered to the circuit board (not shown) by surface adhesion technology. In the figure, the closed magnetic circuit structure 5 is a magnetic glue to avoid magnetic leakage.

The iron core 1 described above is sintered by iron-iron 50 powder (FeNi50) of iron ore powder or soft magnetic material so that the magnetic permeability μ = 60. Since the magnetic permeability is high, the number of turns of the coil 4 is small, the copper loss is about 0.67 w, and the DC resistance DCR is about 6.74 mohm, so that the current is small, and the current withstand current is high and the heat resistance is high.

The above are only the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. That is, the equivalent changes and modifications made by the scope of the patent application of the present invention are covered by the scope of the invention.

100~114‧‧‧Steps

Claims (13)

A method of fabricating a chip inductor includes:
An iron core powder is provided;
Pressing the iron core powder into a Japanese powder core;
The pressed Japanese-shaped powder core is sintered to form the Japanese-shaped powder core into a Japanese-shaped iron core;
After the iron core is fired, an insulating layer is formed on the surface of the iron core;
Forming an electrode layer on the surface of the insulating layer;
Winding a coil on the winding portion of the iron core, the coil is electrically connected to the electrode layer; and sealing the coil region to form a closed magnetic circuit structure, the closed magnetic circuit structure is exposed to expose the electrode layer Forming a wafer-type inductor. The production method according to the first aspect of the invention, wherein the core powder in the step a is an iron-iron powder (FeSi) or a soft magnetic material of iron-nickel 50 powder (FeNi50). The manufacturing method according to claim 2, wherein in the step b, the iron core powder is pressed into a Japanese-shaped powder core by a thermosetting process. The production method according to claim 3, wherein in the step c, the Japanese-shaped powder core is formed into a Japanese-shaped iron core by low-temperature sintering. The manufacturing method of claim 4, wherein the iron core has a frame body, and the frame body has a winding portion, and the winding portion and the frame body have two through grooves. The manufacturing method according to claim 5, wherein the core has a magnetic permeability μ=60 by a sintering technique. The manufacturing method according to claim 6, wherein the insulating layer in the step d is an insulating varnish. The manufacturing method according to claim 7, wherein the electrode layer in the e step is printed with a copper layer by a printing technique, and then a silver layer is plated on the copper layer, or after printing the silver layer, and then silver. An electrode layer is formed by plating tin on the layer. The manufacturing method according to claim 8, wherein the coil in the f step has a two-wire head, and the two-wire head is electrically connected to the electrode layer. The manufacturing method according to claim 9, wherein the coil is a flat bare copper wire. The manufacturing method according to claim 10, wherein the magnetic closed magnetic circuit structure of the g step is a magnetic glue. The manufacturing method of claim 11, wherein the chip inductor has a copper loss of 0.67 w. The manufacturing method of claim 12, wherein the wafer inductor has an equivalent DC resistance of 6.74 mohm.