JP2590019Y2 - Multilayer chip inductor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer chip inductor, and more particularly, to a multilayer chip inductor having high reliability without deteriorating magnetic characteristics even when the size is reduced.

[0002]

2. Description of the Related Art In recent years, miniaturization of electronic components has been demanded in all fields, and in particular, miniaturization of multilayer chip inductors has been strongly demanded.

Conventionally, a multilayer chip inductor has been reduced in size by reducing the thickness of a green sheet constituting a chip and reducing the line width of a coil conductor. For example, the thickness of a green sheet is reduced. The size was reduced to about several tens of μm by baking, and the coil conductor pattern was formed on this sheet with a line width of about 0.1 mm to reduce the size.

In the green sheets on which the coil conductor patterns are formed, through holes for connecting the coil conductor patterns formed on adjacent sheets in the laminating step between layers are formed. Since the size (diameter) could not be made extremely small in consideration of connection reliability, the size (diameter) was about 0.15 mmφ.

For this reason, the coil conductor pattern 2 formed on the thin green sheet 1 has, for example, the shape shown in FIG. Was spread out and formed.

[0006]

However, as described above, the green sheet on which the coil conductor pattern having only the line width of the pattern end portion which is the through hole connecting portion is formed has a misalignment when laminated and crimped. There is a problem that the yield is likely to occur and a decrease in yield cannot be avoided.

[0007] This is because when the conductor portion having a small line width other than the through-hole connection portion has a shape in which the upper surface thereof is not flat and rises in a semi-cylindrical shape, that is, when the conductor is cut in the stacking direction and in a direction parallel to the line width, Its cross section is semicircular,
In addition, the thickness is substantially smaller than the thickness of the conductor portion (through-hole connection portion) having a wide line width and having a flat upper surface.

In other words, as described above, the conductor portion of the coil conductor pattern 2 having a semicircular cross section and a thin line width has only a vertex of the semicircle at the point of contact with the green sheet 1 laminated thereon. In addition to lack of stability, since the thickness of the through-hole connection part is different from that of the conductor part having a flat and wide line width, when the sheets are laminated, as shown in FIG.
This causes a slight inclination, and pressure during crimping is not applied vertically to the conductor having a small line width, resulting in lamination displacement.

The conductor having the same line width as that of the through-hole connection portion has a flat upper surface. Therefore, if all the conductor portions are formed with this line width, the occurrence of lamination displacement due to the above-described factors will be avoided. Although it can be prevented, the result is that the core diameter of the coil is reduced and the magnetic characteristics are reduced, so that it is not practical.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a multilayer chip inductor capable of preventing the occurrence of lamination displacement without deteriorating magnetic characteristics.

[0011]

Means for Solving the Problems The present inventor has made intensive studies to achieve the above object, and as a result, the two ends and the two corners of the U-shaped coil conductor pattern have been reduced by the through hole diameter. It has been found that the above problem can be solved by forming a large line width and forming the other portions with a line width smaller than the diameter of the through hole, and arrived at the present invention.

That is, the present invention provides a laminated chip comprising a green sheet laminate in which a through-hole is formed at a predetermined position and a coil conductor pattern formed by laminating and connecting through holes to form a spiral coil. An inductor, a plurality of through-hole connection portions in the coil conductor pattern, and portions of the coil conductor pattern formed on each sheet when laminated, the upper and lower positions corresponding to the through-hole connection portion, that is, two ends and two corner portions of the shaped conductor pattern of the sheet of co is formed with a large line width than the diameter of the through hole, and a smaller line width than the other portion through hole diameter of the Coil conductor pattern
Multiple through-hole connections and each
Of the coil conductor patterns formed on the
-The thickness of the part where the hole connection part and the top and bottom position correspond
An object of the present invention is to provide a multilayer chip inductor characterized by being formed thin .

[0013]

The laminated chip inductor according to the present invention is obtained by laminating green sheets having a through-hole and a coil conductor pattern composed of a conductor having a line width larger than the diameter of the through-hole and a conductor having a smaller line width. It is configured by connecting through holes.

That is, the coil conductor pattern formed on the sheet constituting the multilayer chip inductor of the present invention has a through hole connecting portion and a through hole of the coil conductor pattern formed on the adjacent sheet when laminated. The portion corresponding to the connection portion and the upper and lower positions have a line width larger than the through hole diameter, and the other portions have a line width smaller than the through hole diameter.

By forming the coil conductor pattern 2 with such a line width, lamination displacement can be prevented. This is because when a sheet on which a coil conductor pattern having the above line width is formed is laminated, as shown in FIG. 3, a conductor portion having a line width larger than the through hole diameter (a conductor portion having a flat upper surface and a thicker thickness) is formed. Since the adjacent sheet 1 is supported horizontally, the pressure at the time of crimping is applied vertically to a conductor portion having a line width smaller than the through hole diameter (a conductor portion having a semicircular cross section). This pressure is applied to a conductor portion having a large line width to a large extent, and is applied to a conductor portion having a small line width to a small extent.

Further, in the coil constituted by the coil conductor pattern formed with the line width as described above, the magnetic characteristics of the inductor do not decrease because the projected sectional area of the magnetic core does not decrease.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by the following embodiments.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a method for manufacturing a multilayer chip inductor according to the present invention will be described below.

First, four types of U-shaped coil conductor patterns as shown in FIG. 1 are used for a ceramic green sheet 1 having through holes 3 formed at predetermined positions by using a conductive paste containing Ag as a main component. 2 (spiral coil is formed by stacking and connecting through holes)
Was screen printed.

The U-shaped coil conductor pattern 2 is vertically connected to the through-hole connection part and the through-hole connection part of the coil conductor pattern formed on each sheet when laminated. positions are corresponding portions (four corners in the U-shaped), which is much larger slightly than the diameter of the through hole 3, and the other portion is formed with a smaller line width than the diameter of the through hole ing.

Next, these sheets are laminated on the dummy sheet in a predetermined configuration (a configuration in which a helical coil is internally provided by the coil conductor pattern 2), and a dummy sheet is further laminated thereon, and FIG. To obtain a laminate as shown in FIG.
Next, the laminate was pressed and fired, and then a conductive paste for an external electrode was applied to the end face from which the coil end portion was led out, and baked to form an external electrode.

The multilayer chip inductor obtained as described above had no lamination displacement and had excellent magnetic properties.

[0023]

The multilayer chip inductor according to the present invention is capable of preventing the occurrence of lamination displacement without reducing the projected sectional area of the magnetic core. Therefore, the multilayer chip inductor of the present invention has high reliability without a decrease in magnetic properties and can be manufactured with a high yield.

[Brief description of the drawings]

FIG. 1 is a plan view showing a sheet constituting an example of the multilayer chip inductor of the present invention, wherein (a) to (d) are plan views showing a green sheet on which various coil conductor patterns and through holes are formed. is there.

FIGS. 2A to 2D are views showing sheets constituting an example of a conventional multilayer chip inductor, wherein FIGS. 2A to 2D are plan views showing green sheets on which various coil conductor patterns and through holes are formed. FIGS. .

FIG. 3 is a side view showing a laminated body constituting an example of the laminated chip inductor of the present invention.

FIG. 4 is a side view showing a laminated body constituting an example of a conventional laminated chip inductor.

[Explanation of symbols]

 1 Green sheet 2 Coil conductor pattern 3 Through hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H01F 17/00 H01F 27/28 H05K 1/02 H05K 3/00 H05K 1/16

Claims (1)

(57) [Scope of request for utility model registration] 1. A laminated chip inductor comprising a green sheet laminate having a through hole at a predetermined position and a coil conductor pattern formed by laminating and connecting through holes to form a helical coil. A plurality of through-hole connection portions in the coil conductor pattern, and a portion of the coil conductor pattern formed on each sheet when laminated, the top and bottom positions corresponding to the through-hole connection portion, that is, The two end portions and the two corner portions of the U-shaped conductor pattern are formed with a line width larger than the through hole diameter,
Or other portion is a small line width than the diameter of the through hole
A plurality of through hoes in the coil conductor pattern;
Is formed on each sheet when stacked
Up and down with the through hole connection part of the coil conductor pattern
Are formed thinner than the thickness of the corresponding part .