JPH0917634A - Multilayer type inductor - Google Patents

Abstract

PURPOSE: To obtain a small-sized multilayer inductor wherein inductance value is large and Q characteristics are excellent. CONSTITUTION: Coil conductors 2, 3 and an insulating film 8 of low dielectric constant are alternately formed on the upper surface of an insulating board 1 by using photolithography means. Polyimide resin or the like is used as material of the insulating film 8 of low dielectric constant. The coil conductors 2, 3 are electrically connected in series through a window 8a formed in the insulating film 8 of low dielectric constant and constitute a coil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated inductor, and more particularly to a laminated inductor used as a high frequency air core coil or the like.

[0002]

2. Description of the Related Art Heretofore, as an inductor of this type, one having a spiral coil conductor 71 provided on an upper surface of an insulating substrate 70 is known as shown in FIG. One end 71a of the coil conductor 71 is electrically connected to the external electrode 76 provided on the left end of the insulating substrate 70. The other end portion 71b is connected to the insulating substrate 70 via the extraction electrode 73.
Is electrically connected to the external electrode 77 provided at the right end of the. The extraction electrode 73 intersects with the coil conductor 71 via the insulating coating 72.

[0003]

In the conventional inductor, when the inductance value is increased without increasing the size of the insulating substrate 71, the coil conductor 7 is used.
It is necessary to reduce the line width of 1 and increase the number of windings. However, when the line width is reduced, the resistance of the coil conductor increases, and the Q characteristic of the inductor in the high frequency range deteriorates.

Therefore, an object of the present invention is to provide a small-sized laminated inductor having a large inductance value and an excellent Q characteristic.

[0005]

In order to achieve the above object, coil conductors and low dielectric constant insulating films respectively formed by means of photolithography are alternately laminated on the surface of an insulating substrate, It is characterized in that the coil conductors are interlayer-connected to each other at a window provided in the dielectric constant insulating film.

[0006]

With the above construction, the coil conductors are laminated on the insulating substrate, and the coil conductors are electrically connected in series at the window provided in the low dielectric constant insulating film to form a coil. The configured coil, when increasing the inductance value,
It suffices to increase the number of laminated coil conductors to increase the coil wire length, and it is not necessary to reduce the wire width or increase the size of the insulating substrate.

[0007]

Embodiments of the laminated inductor according to the present invention will be described below with reference to the accompanying drawings together with the manufacturing method thereof. [First Embodiment, FIGS. 1 to 6] As shown in FIG. 1, a coil conductor 2 is formed on an upper surface of an insulating substrate 1. Coil conductor 2
One end 2a of the one is exposed on the left side of the insulating substrate 1. The coil conductor 2 is formed by means of photolithography. That is, a metal film of Ag, Au, Cu or the like is formed on the entire upper surface of the insulating substrate 1 by a dry plating method such as sputtering or vapor deposition. Next, after a photosensitive resist film is applied to the surface of the metal film and dried, a mask film is applied to the photosensitive resist film to expose a desired portion.
Next, the photosensitive resist film is developed to expose unnecessary portions of the metal film from the photosensitive resist film. Next, after removing the exposed metal film by etching, the photosensitive resist film is peeled off to form a desired coil conductor 2.

Next, as shown in FIG. 2, a low dielectric constant insulating film 8 is formed on the upper surface of the insulating substrate 1 by means of photolithography.
To form The low dielectric constant insulating film 8 has a window 8a for exposing the other end 2b of the coil conductor 2. As a material of the low dielectric constant insulating film 8, a polyimide resin or the like is adopted. Further, as shown in FIG. 3, the coil conductor 3 is formed on the upper surface of the low dielectric constant insulating film 8 by photolithography. One end 3a of the coil conductor 3 is
It is electrically connected to the end 2b of the coil conductor 2 exposed in the window 8a.

Next, as shown in FIG. 4, a low dielectric constant insulating film 9 is formed on the upper surface of the insulating substrate 1 by means of photolithography.
To form This low dielectric constant insulating film 9 has a window 9a for exposing the other end 3b of the coil conductor 3. Further, as shown in FIG. 5, the coil conductor 4 is formed on the upper surface of the low dielectric constant insulating film 9 by photolithography. One end 4a of the coil conductor 4 is electrically connected to the end 3b of the coil conductor 3 exposed in the window 9a. The other end 4b of the coil conductor 4 is exposed on the right side of the insulating substrate 1.

Next, as shown in FIG. 6, external electrodes 15 and 16 are sputtered on the left and right ends of the insulating substrate 1, respectively.
It is formed by vapor deposition or printing. The external electrode 15 is electrically connected to the end portion 2a of the coil conductor 2,
6 is electrically connected to the end 4b of the coil conductor 4.

In the multilayer inductor thus obtained, the coil conductors 2 to 4 are electrically connected in series by the windows 8a and 9a provided in the low dielectric constant insulating films 8 and 9, respectively.
Make up the coil. In order to increase the inductance value of this coil, it is sufficient to increase the number of laminated coil conductors to increase the wire length of the coil, and it is not necessary to reduce the wire width or increase the size of the insulating substrate 1. Absent. Therefore, it is possible to obtain a small laminated inductance having a good Q characteristic. Moreover, since the low dielectric constant insulating films 8 and 9 are used,
Even if the coil conductors 2 to 4 are formed to overlap each other, the stray capacitance between them can be reduced, and the self-resonant frequency can be improved. Furthermore, coil conductors 2 to 4
Is formed by means of photolithography, the finish accuracy of the line width is high, and it is possible to narrow the inductance value of the coil.

[Second Embodiment, FIGS. 7 to 13] As shown in FIG. 7, a spiral coil conductor 22 is formed on the upper surface of an insulating substrate 21.
Are formed by means of photolithography. One end 22a of the coil conductor 22 is exposed on the left side of the insulating substrate 21. Next, as shown in FIG. 8, the low dielectric constant insulating film 2 is formed on the upper surface of the insulating substrate 21 by photolithography.
8 is formed. This low-dielectric-constant insulating film 28 has a window 28a for exposing the other end 22b of the coil conductor 22.
have. Next, the coil conductor 23 is formed on the upper surface of the low dielectric constant insulating film 28 by photolithography.
One end 23a of the coil conductor 23 is electrically connected to the end 22b of the coil conductor 22 exposed in the window 28a.

Next, as shown in FIG. 9, the insulating substrate 21
A low dielectric constant insulating film 29 is formed on the upper surface of the substrate by photolithography. The low-dielectric-constant insulating film 29 has a window 29 for exposing the other end 23b of the coil conductor 23.
a. Next, as shown in FIG. 10, the spiral coil conductor 24 is formed on the upper surface of the low dielectric constant insulating film 29 by photolithography. The one end 24a of the coil conductor 24 has the coil conductor 2 exposed at the window 29a.
3 is electrically connected to the end portion 23b.

Next, as shown in FIG. 11, the insulating substrate 2
A low-dielectric-constant insulating film 30 is formed on the upper surface of 1 by photolithography. The low-dielectric-constant insulating film 30 has a window portion 30 for exposing the other end portion 24b of the coil conductor 24.
a. Next, as shown in FIG. 12, the coil conductor 25 is formed on the upper surface of the low dielectric constant insulating film 30 by photolithography. One end 2 of the coil conductor 25
5a is electrically connected to the end 24b of the coil conductor 24 exposed in the window 30a. The other end 25b of the coil conductor 25 is exposed on the right side of the insulating substrate 21.

Further, external electrodes 35 and 36 are formed on the left and right ends of the insulating substrate 21 by sputtering, vapor deposition or printing. The external electrode 35 is the coil conductor 22.
Is electrically connected to the end 22a of the coil conductor 25, and the external electrode 36 is electrically connected to the end 25b of the coil conductor 25. The coil conductors 22 to 25 are electrically connected in series at window portions 28a, 29a, 30a provided in the low dielectric constant insulating films 28, 29, 30 to form a coil.

FIG. 13 is a cross-sectional view of the laminated inductor thus obtained, in which coil conductors 22 and 24 are arranged so as to face each other in the thickness direction. This laminated inductor has the same effects as the laminated inductor of the first embodiment.

[Third Embodiment, FIG. 14] As shown in FIG. 14, the laminated inductor of the third embodiment has a coil conductor 22.
And 24 are substantially the same as the laminated inductor of the second embodiment except that they are deviated in the direction perpendicular to the thickness direction, and the same parts and the same parts are designated by the same reference numerals. . By staggering the coil conductors 22 and 24, the stray capacitance generated between the coil conductors 22 and 24 can be further suppressed, and the high frequency characteristics can be further improved in addition to the function and effect of the laminated inductor of the second embodiment. Can be made.

[Other Embodiments] The laminated inductor according to the present invention is not limited to the above-mentioned embodiments, but may be variously modified within the scope of the invention. In particular, the shape of the coil conductor, the number of layers, and the like are arbitrary and can be variously changed according to the specifications. Further, in the multilayer inductor of each example, it is possible to arbitrarily cover the surface of the outermost coil conductor with an insulating layer.

[0019]

As is apparent from the above description, according to the present invention, the coil conductors and the low dielectric constant insulating film are alternately laminated on the insulating substrate by means of photolithography, and each coil conductor is Since the coil is constructed by electrically connecting in series at the window provided in the dielectric constant insulating film, when increasing the inductance value, the number of laminated coil conductors may be increased to increase the coil wire length. There is no need to reduce the line width as in the past. As a result, a small laminated inductor having a large inductance value and excellent Q characteristics can be obtained.

Further, by using the low dielectric constant insulating film, the stray capacitance between the coil conductors can be reduced,
The self-resonant frequency can be improved. Further, by arranging the adjacent coil conductors so as to be displaced in the direction perpendicular to the thickness direction, the stray capacitance generated between the coil conductors can be further suppressed, and the high frequency characteristics can be further improved.

Further, since the coil conductor is formed by means of photolithography, the finish accuracy of the line width is high, and the inductance value of the coil can be narrowed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a manufacturing procedure of a first embodiment of a laminated inductor according to the present invention.

FIG. 2 is a perspective view showing a manufacturing procedure following FIG. 1;

FIG. 3 is a perspective view showing a manufacturing procedure following FIG. 2;

FIG. 4 is a perspective view showing a manufacturing procedure following that of FIG. 3;

FIG. 5 is a perspective view showing a manufacturing procedure following that of FIG. 4;

FIG. 6 is a perspective view showing the outer appearance of the multilayer inductor of the first embodiment.

FIG. 7 is a perspective view showing a manufacturing procedure of a second embodiment of the laminated inductor according to the present invention.

FIG. 8 is a perspective view showing a manufacturing procedure following that of FIG. 7;

FIG. 9 is a perspective view showing a manufacturing procedure following that of FIG. 8;

FIG. 10 is a perspective view showing a manufacturing procedure following that of FIG. 9;

FIG. 11 is a perspective view showing a manufacturing procedure following that of FIG. 10;

FIG. 12 is a perspective view showing the outer appearance of a laminated inductor according to a second embodiment.

FIG. 13 is a sectional view taken along the line XIII-XIII of FIG. 12;

FIG. 14 is a sectional view showing a third embodiment of the laminated inductor according to the present invention.

FIG. 15 is a perspective view showing the appearance of a conventional laminated inductor.

[Explanation of symbols]

 1 ... Insulating substrate 2, 3, 4 ... Coil conductor 8, 9 ... Low dielectric constant insulating film 8a, 9a ... Window part 21 ... Insulating substrate 22, 23, 24, 25 ... Coil conductor 28, 29, 30 ... Low Dielectric insulating film 28a, 29a, 30a ... Window portion

Claims (1)

[Claims] 1. A coil conductor and a low dielectric constant insulating film respectively formed by photolithography means are alternately laminated on a surface of an insulating substrate, and a window portion provided in the low dielectric constant insulating film is used for the above. A laminated inductor characterized in that coil conductors are interconnected between layers.