JPH10335142A - Chip inductor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small chip inductor of superior performance easily manufactured, and a method for manufacturing it. SOLUTION: A winding wire part of a coil 5 parallel to a substrate is pattern-formed on the surfaces of two substrates facing each other, and a magnetic core is disposed at the middle if desired, and both the substrates 1 and 2 are bonded with an anisotropic conductive adhesive agent 3, so that the both ends of the coil patterns of both the substrates 1 and 2 are conductively- connected to each other, so that the coil 5 is constituted with the pattern and the anisotropic conductive adhesive agent 3. A coil terminal and a terminal electrode 4 of an outer surface of the substrate are connected to each other at a conductive part 6 of an inner surface of a through-hole. A shielding structure can be also manufactured by providing the surface of the substrate with a shield film. In manufacturing, two aggregate substrates in which a plurality of chip inductor regions are matrix-disposed are bonded with the anisotropic conductive adhesive agent 3 and divided into many pieces by cutting along a boundary line, so that a large number of chip inductors are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a very small inductance component, and more particularly to a chip inductor suitable for use in electronic equipment manufactured by surface mounting technology.

[0002]

2. Description of the Related Art In recent years, surface mounting circuit structures have become widespread with the miniaturization of electronic equipment. For example, Japanese Unexamined Patent Publication No. 5-82349 discloses an insulated substrate for use as an inductance component, that is, a chip inductor. A spiral coil formed of a conductive material such as copper on the surface is disclosed. 13A, the surface of a winding core 101 of a columnar insulator is coated with a conductive material such as copper by plating, and a part of the conductive film is spirally shaped like 102 by a laser beam or the like. By removing, the coil 103 is formed with the remaining conductive film.

[0003] On the other hand, FIG. 13 (B) is an application filed by the inventor of the present invention in Japanese Patent Application No. Hei 9-17667, in which a winding portion 105, 1
06 is wound and a coil is formed.
7, 108 are provided. In this production, a large number of chip inductors, which are completed and cut off, are used, and a large number of regions serving as individual winding cores 104 are arranged in a matrix on the surface thereof. A winding portion 105 is formed by patterning a conductive material on the upper and lower surfaces of the collective substrate, and a plurality of through holes are provided in portions of the side surface of the winding core 104 which will become the winding portions 106 to cover the inner surface with the conductive material. The individual chip inductors are obtained by cutting the collective substrate along a line passing through the through-hole, and the winding portion 106 on the side surface is a part of a conductor formed on the inner surface of the through-hole.

[0004]

The above-described conventional chip inductors are each useful but have the following problems. That is, in the case where the spiral pattern is provided on the substrate, the coil, which should be three-dimensional, is formed into a planar shape, so that the number of turns of the coil cannot be increased, and a coil having a very large inductance cannot be obtained. Alternatively, the one shown in FIG. 13A requires expensive equipment such as a laser processing machine for its manufacture, and if the number of coil turns is increased, the length of the conductive film removed increases, and in proportion to this, Processing time increases and production costs increase.

FIG. 13B proposed by the inventor of the present invention can efficiently manufacture a three-dimensional coil by taking a large number of pieces by using ordinary printed circuit manufacturing equipment and technology, and the processing time is reduced by the number of coil turns. Although there is an advantage that it is not affected, there is a limit in that the minimum pitch of the coil cannot be made smaller than that because there is a lower limit on the distance between through holes that can be provided in the collective substrate in the manufacturing process. The present invention solves these problems, and provides a chip inductor which is small in size, has good performance, and is easy to manufacture, and a method for manufacturing the same.

[0006]

A chip inductor according to the present invention has a configuration in which two insulating substrates are bonded to each other, and a rectangular coil having a substantially flat cross section is built in between the two substrates. is there. The portion of the coil winding parallel to the substrate and corresponding to the long side of the rectangular cross section of the coil is a conductive pattern formed on the inner surface of the substrate, and the portion perpendicular to the substrate and corresponding to the short side of the coil cross section is two. Formed of an anisotropic conductive adhesive for bonding the substrates. That is, on one surface of each substrate, a coil pattern, which is a parallel line segment corresponding to the long side of the coil cross section, is formed of a conductive material, and the pattern formation surfaces of the two substrates are formed so that the coil has a cross-sectional area. At regular intervals, they are joined by an anisotropic conductive adhesive.

[0007] The parallel coil pattern of the two substrates is
When viewed in a plan view, they are arranged in a zigzag manner, and only both ends overlap. Therefore, each coil pattern on the board is
The coil pattern is electrically connected to the coil pattern of the mating substrate at the overlapping portions at both ends by the anisotropic conductive adhesive, and the coil pattern and the anisotropic conductive adhesive are each part of a winding to form a coil. . The anisotropic conductive adhesive does not produce conductivity in the direction parallel to the substrate.

[0008] A magnetic core made of a magnetic material can be arranged between the two substrates as required, whereby a coil containing the magnetic core can be obtained. As far as the inventors know, there are few examples of chip inductors with a magnetic core.

The surface of each substrate opposite to the surface on which the coil pattern is formed is the outer surface of the chip inductor, and terminal electrodes are provided on the outer surface and connected to the internal coil terminals. If the outer surface of the substrate other than the terminal electrode portion is covered with a conductor, a magnetic material, or the like, an electrical and magnetic shielding action can be obtained, and the performance of the chip inductor can be further enhanced.

The production of such a chip inductor is performed by a multi-cavity method using a collective substrate. That is, a large number of regions to be substrates of individual chip inductors are arranged in a matrix on a collective substrate as a material, and required coil patterns and terminal electrodes are formed in each region. A conductive portion for connecting the coil pattern and the terminal electrode on the front and back of the same substrate is formed on the end surface of the substrate.A preferable method for this is to provide a through hole in the collective substrate and to cover the inner surface with a conductive layer coated on the inner surface of the completed chip. That is, the conductive portion is left on the end face to become a conductive portion. And for those with a magnetic core, a magnetic core of magnetic material is placed between two collective substrates, and both substrates are joined with an anisotropic conductive adhesive and cut along the boundary of each region. By doing so, a large number of chip inductors can be efficiently manufactured from one collective substrate.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing a configuration of a first embodiment of a chip inductor according to the present invention. 1,
Reference numeral 2 denotes a first substrate and a second substrate, each of which is made of an insulating material, and are joined by an anisotropic conductive adhesive 3;
Are provided at both ends with terminal electrodes 4 for connection to a circuit board. A coil 5 is formed between these two substrates, and an end of the coil 5 is connected to the terminal electrode 4 by a conductive portion 6 provided on an end surface of the substrate 2. Although not shown in FIG. 1 to avoid complexity, a magnetic core made of a magnetic material can be arranged inside the coil to increase the inductance.

FIG. 2 is an exploded view of the chip inductor of FIG. The material of the first and second substrates 1 and 2 is paper, glass,
It is an insulating material such as PET, composite material, ceramics, etc.
The same materials as those used for a printed circuit board, a liquid crystal cell, or the like can be used. Then, coil patterns 7 and 8 are formed on the surfaces of these substrates facing each other with a conductive material, respectively. The pattern is formed by printing or photolithography on a copper foil pasted on a material substrate like a printed circuit board, or by forming an ITO film by vacuum evaporation, sputtering, plasma CVD, etc. like a liquid crystal cell. An appropriate method can be used depending on the material and dimensions of the slab. Reference numeral 3 denotes an anisotropic conductive adhesive, and reference numeral 9 denotes, for example, a magnetic core made of ferrite.

FIG. 3 is a sectional view perpendicular to the axis of the coil. FIG. 3 (A) is an exploded state corresponding to FIG. 2, and FIG. 3 (B) is FIG.
This is a completed state corresponding to. As is well known, the conductive adhesive is an adhesive containing the conductive particles 10, and the conductive particles are metal-plated plastic particles having a thin metal layer formed on the surface of fine plastic particles, or metal particles. It is preferable to apply a normal non-conductive adhesive 11 to the magnetic core 9 in order to fix the magnetic core to the substrate.

A chip inductor is obtained by superposing and heating / pressing the components as shown in FIG. 3A and joining them as shown in FIG. 3B. As shown in FIG. 2, the coils of both substrates 1 and 2
The patterns 7 and 8 have a zigzag arrangement in a plane, and only a part of both ends overlap. As shown in FIG. 3 (B), the conductive particles 10 are interposed at the overlapping portions of both ends of the coil pattern, and electrical conduction occurs in a direction perpendicular to the substrate. No conduction occurs in the direction parallel to the substrate. Thus, the distinction between conduction and non-conduction is made depending on the direction, and is called anisotropy.

The coil patterns 7 and 8 form coil windings parallel to the substrate, and the conductive particles 10 contained in the anisotropic conductive adhesive 3 form coil windings perpendicular to the substrate, thereby allowing both substrates 1 2, the coil 5 is formed as shown in FIG. In FIG. 3B, the coil pattern 7,
8, the thickness of both ends is increased, but this is exaggerated to show the conduction by the conductive adhesive, and the actual coil
This is not the case for the thickness of the pattern.

The above is the basic configuration of the chip inductor of the present invention. For mass production of such a chip inductor, it is convenient to carry out mass production using a collective substrate. I do. In FIG. 4, reference numeral 21 denotes a first collective substrate, and reference numeral 22 denotes a second collective substrate. These substrates are divided into many regions that become individual chip inductors by boundaries 23 and 24, and coil patterns 7 and 8 are formed in respective regions of the substrate surface facing each other.
The second collective substrate 2 is also provided with a terminal electrode pattern 4a, which is connected to a terminal of the coil pattern 8. Although not visible in FIG. 4, a pattern of the terminal electrode 4 of the chip inductor of FIG. 1 is formed on a portion of the lower surface of the second collective substrate 22 which is on the back side of the terminal electrode pattern 4 a,
The terminal electrode pattern 4a on the upper surface and the terminal electrode 4 on the lower surface are electrically connected by a through hole 25 whose inner surface is covered with a conductor.

Reference numeral 26 denotes an anisotropic conductive adhesive, which in this case is a film material punched in a lattice. Anisotropic conductive film (Anisotoropic Conductive Fil)
m: ACF) etc. and has a thickness of several 10μ
For m, an arbitrary shape including the shape as shown in FIG. 4 is available, and is usually held on a sheet-like carrier called a separator or the like, which is omitted in FIG. Such an anisotropic conductive adhesive 26 is temporarily press-bonded to the second collective substrate 22 to peel off the separator, and a strip-shaped magnetic core 28 is placed in each groove 27 of the anisotropic conductive adhesive 26. Magnetic core 2
8 is preferably coated with a resin by a so-called parylene treatment or the like. As described above, the magnetic core 28 is coated with a normal non-conductive adhesive.

A first collective board 21 is placed thereon, and these operations are performed by aligning each component with reference holes 29. By arranging the components in this way, the two substrates 21 and 22
Are joined by heating and pressing using a jig.
By dicing along the inner core 28 along 4,
Each separated part becomes a chip inductor. FIG. 5 shows a cross section perpendicular to the coil axis of the assembled substrate thus joined. Each part obtained by dividing this at the boundary 31 becomes a chip inductor having a cross section as shown in FIG.

Since the through-hole groups 25 of the second collective substrate 22 in FIG. 4 are arranged on the boundary line 23, when the substrate is cut, a dent remains on the cut surface as shown in FIG. The conductor serves as the conductive portion 6 connecting the conductive patterns on both surfaces of the substrate.

Without using the magnetic core 28 made of a bar as shown in FIG.
Although illustration is omitted, an insulating film is coated on the coil patterns 7 and 8 of the first and second collective substrates 21 and 22, and a stripe pattern of a magnetic material is provided on one or both of them. This can be a magnetic core. Further, depending on the specifications of the components, the magnetic core 28 may be omitted to form an air-core coil. The magnetic cores 9 and 28 in FIGS. 2 and 4 serve as a spacer for providing a fixed distance between the two collective substrates, but when these magnetic cores are not used, a resin is used as a spacer between the substrates. Rod-shaped parts, resin particles, glass beads, and the like.

Various methods other than the method shown in FIG. 4 are possible for the manufacturing method using the collective substrate. For example, FIG. 6 shows another form of the second collective board 31. This is different from the round-hole through-hole group 25 in FIG. It is provided. The long hole 32 is formed by coating an inner surface of a long hole formed by punching, end milling, or the like with a conductor by electroless plating, vapor deposition, sputtering, or the like. When such an integrated substrate is used, a chip inductor obtained by dicing after bonding of the substrate has a conductive surface 33 at the end surface of the substrate as shown in FIG. .

In FIG. 2, the first substrate 1 (and thus the first collective substrate 21 in FIG. 4) has only the coil pattern 7 on the lower surface and no pattern on the upper surface. This suffices for the basic configuration of the coil. However, if the first substrate is provided with conductive layers on both surfaces, the performance of the chip inductor can be further improved. In the exploded view of the chip inductor shown in FIG.
A conductive material is coated on the entire upper surface of the first substrate 1 to form a shield film 41. In order to provide such a coating, a substrate material having copper foil adhered to both sides, such as a double-sided printed board, may be used, or it may be formed by plating or the like in a later step. And, by the conductive part 42 by the through hole,
The shield film 41 on the upper surface and the land portion 43 of the conductor on the lower surface of the first substrate are connected. On the other hand, also on the lower surface of the second substrate 2, a portion other than the terminal electrode 4 is covered to form a shield film 44, and is connected to the conductor land portion 46 on the upper surface by a conductive portion 45 of a through hole.

FIG. 9 shows a cross section perpendicular to the coil axis of the chip inductor using the components having such a configuration. As described above, the coils are formed by the coil patterns 7 and 8 and the anisotropic conductive adhesive 3, and the lands 43 and 46 on the inner surfaces of both substrates are also formed by the anisotropic conductive adhesive 3. The shield films 41 and 44 on the outer surface of the substrate are connected to the conductive portions 42 and 4
5 through the anisotropic conductive adhesive 3. Therefore, if a part of the shield film is connected to the ground line of the circuit at the time of mounting on a circuit board, a grounded shield structure will be obtained,
By exerting a function such as electromagnetic shielding, it is possible to prevent the leakage magnetic flux of the coil from interfering with the operation of other circuit parts and, conversely, from affecting the coil itself from the surroundings. If the shield films 41 and 44 are made of a magnetic material, magnetic shielding is performed.

In FIG. 8, the upper surface of the first substrate 1, that is, the entire upper surface of the chip inductor is formed as a shield film 41, but the chip inductor of FIG. The substrate 1 is also provided with a shield film 41, a terminal electrode 51, and a conductive portion 52. The terminal electrodes 51, 4 on the upper and lower surfaces of the chip inductor are anisotropic on the bonding surface of the substrate via the conductive portions 52, 6. They are connected by the conductive adhesive 3. In this way, the chip inductor becomes a vertically symmetric chip inductor, and it is not necessary to distinguish between the upper and lower parts when mounting.

In the chip inductor of FIG. 11, the first substrate 1 and the second substrate 2 are both manufactured by using an aggregate substrate provided with elongated through holes as shown in FIG. , A conductive surface 33 formed on the entire end face
And 53 are connected to the inner pattern and interconnected by the anisotropic conductive adhesive 3. The upper and lower shield films 41 and 44 are interconnected with the conductive portions 42 and 45 by the anisotropic conductive adhesive 3.

The elongated through-holes in the collective substrate may not be in the direction of the boundary line 23 as shown in FIG. 6 but may be in the direction of the orthogonal boundary line 24 (not shown). The conductive layer on the inner surface of the elongated through-hole in the chip inductors thus obtained is a conductive surface that covers the end face of the substrate parallel to the coil axis. FIG. 12 shows the appearance of such a chip inductor. Here, the conductive surfaces 55 and 57 at the end surfaces parallel to the length of the first substrate 1 and the conductive surfaces 56 and 58 parallel to the length of the second substrate 2 are conductive layers formed on the inner surface of the long hole. The terminal electrodes 4 and 51 on the upper and lower surfaces are connected to the internal pattern by conductive surfaces 55 and 56, and are electrically connected by the anisotropic conductive adhesive 3. The shield films 41 and 44 are formed on the inner surface of the substrate by the conductive surfaces 57 and 58. The lands are connected to the lands provided along the edges, and the lands are electrically connected by the anisotropic conductive adhesive 3.

In the sectional view of FIG. 9, the conductive portions 42 and 45 are regarded as conductive surfaces 57 and 58 in FIG.
It is sufficient to consider that lands 3 and 46 are lands on the inner surface of the substrate and extend in the direction perpendicular to the paper surface along the edge of the substrate. 12 has terminal electrodes 4 on the upper and lower surfaces.
51, and the conductive surfaces 55 and 56 on the side surfaces also serve as terminal electrodes, so that not only the upper surface or the lower surface can be joined to the circuit board in a flat shape, but also the side surface can be joined to the circuit board in a vertical shape. The degree of freedom of component arrangement in mounting is increased.

Referring to FIG.
Is a boundary between the terminal electrode and the shield film, and the conductive surfaces 55 and 57 (or 56 and 58) are separated. This can be done by separating the through-holes forming the conductive surfaces 55 and 57 (or 56 and 58) or by forming a conductive layer with a common long-hole through-hole and by photolithography of the inner surface of the long hole at 59 locations. The conductor may be removed to separate the conductive surfaces 55 and 57 (or 56 and 58).

The elongated through holes can be used not only in one direction of the collective substrate but also in both directions orthogonal to each other. Of course, in such an arrangement, the entire through-hole cannot be formed in a shape continuous with the entire substrate, but is formed in an intermittent shape as appropriate. As mentioned above, although several embodiments were shown about the chip inductor of the present invention and its manufacturing method,
It will be understood from the above description that various other configurations are possible within the scope of the present invention.

[0030]

As described above, the present invention relates to a chip inductor in which a coil winding is formed by a pattern on a substrate and an anisotropic conductive adhesive, and the processing time is affected by the number of coil windings. Therefore, it is possible to increase the number of turns per unit length by reducing the pitch of the coil winding. As a result, a thin and small chip inductor having a thickness of about 1 mm can be realized. A magnetic core can be easily obtained and a large inductance can be obtained. If a shield film is provided on the outer surface, a shield structure is formed, and electrical and magnetic interference with surrounding circuits can be prevented. As a manufacturing method,
Suitable for mass production because a large number of pieces are taken using a collective board,
No special processing equipment or processing method is required, and products can be provided at low cost. As a result, miniaturization and higher performance of electronic devices,
It greatly contributes to lower prices.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a first embodiment of a chip inductor according to the present invention.

FIG. 2 is an exploded view of the chip inductor of FIG.

3A and 3B are cross-sectional views of a chip inductor perpendicular to a coil axis, wherein FIG. 3A corresponds to FIG. 2 and FIG.

FIG. 4 is a perspective view of a situation in which the chip inductor of FIG. 1 is manufactured using a collective substrate.

5 is a cross-sectional view perpendicular to the coil axis in a state where the collective substrates of FIG. 4 are joined.

FIG. 6 is a perspective view of a second collective substrate having elongated through holes.

FIG. 7 is an external view of another embodiment of a chip inductor.

FIG. 8 is an exploded view of yet another embodiment of a chip inductor.

9 is a cross-sectional view perpendicular to the coil axis in a completed state of the chip inductor of FIG. 8;

FIG. 10 is an external view of still another embodiment of a chip inductor.

FIG. 11 is an external view of still another embodiment of a chip inductor.

FIG. 12 is an external view of still another embodiment of a chip inductor.

FIG. 13 is an external view of a conventional chip inductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 2nd board | substrate 3, 26 Anisotropic conductive adhesive 4, 51 Terminal electrode 5 Coil 6, 42, 45, 52 Conductive part 7, 8 Coil pattern 9, 28 Magnetic core 10 Conductive particle 11 Adhesive 21 First collective substrate 22, 31 Second collective substrate 23, 24 Boundary line 25 Through hole 32 Slotted through hole 33, 53, 55, 56, 57, 58 Conductive surface 41, 44 Shielding film 101, 104 Core

Claims (7)

[Claims] 1. The method according to claim 1, wherein a part of a coil winding is formed on each of the two insulating substrates by a conductive pattern, and the two substrates are joined by an anisotropic conductive adhesive with their pattern forming surfaces facing each other. A chip inductor in which a coil is formed between both substrates by a conductive pattern and an anisotropic conductive adhesive, wherein an anisotropic conductive adhesive connecting both ends of the pattern forms another portion of the coil winding. 2. The chip inductor according to claim 1, wherein a terminal of the coil and a terminal electrode provided on a surface of the chip inductor are connected by a conductive portion formed on an end surface of the substrate. 3. The chip inductor according to claim 1, wherein a magnetic core is provided between the two substrates so as to include the magnetic core. 4. The chip inductor according to claim 1, wherein a spacer is arranged and bonded between two substrates. 5. The chip inductor according to claim 1, wherein a shield film is formed on an outer surface. 6. A method of manufacturing a chip inductor, comprising: forming a part of a winding of a coil by a conductive pattern on each of two regions of a collective substrate in which regions each serving as a chip inductor are arranged in a matrix. A chip in which a coil is formed between the substrates by a conductive pattern and an anisotropic conductive adhesive by joining the two assembled substrates with anisotropic conductive adhesive with the pattern forming surfaces facing each other, and separating the respective regions. A method of manufacturing a chip inductor by obtaining a large number of inductors. 7. The method for manufacturing a chip inductor according to claim 6, wherein any one of the following methods is arbitrarily selected and used in combination, and the method includes the steps of: By using a round hole or a through hole group of long holes provided on both sides and using a conductive film coated on the inner surface, the two aggregated substrates are joined with an anisotropic conductive adhesive to separate the above-described regions. A method in which the conductive film on the inner surface of the through hole is left on the end face of the substrate to form a conductive portion that connects both surfaces of the substrate, or a method in which a magnetic core is arranged and bonded between two collective substrates, or between two collective substrates. And a method of using two or more collective substrates with a shield film formed on one or both of them.