JP6986796B1 - Coil structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a wound coil by using a bonding wire. SOLUTION: The coil structure 10 has a substrate 1, a plurality of pads 3 and 4 formed on the substrate 1, and a wire 6 connecting the two pads 3 and 4, and the pads 3 and 4 and the wire 6 are provided. The conductor portions including the above are arranged so as to form a spiral or a spiral. The pads 3 and 4 are arranged on the front and back sides via a through conductor 2 penetrating the substrate 1, and the first surface pad 3a and the second surface pad 3b formed on the surface are connected by a first surface wire 6ab. The first back surface pad 4b and the third back surface pad 4c formed on the back surface are connected to the second front surface pad 3b by a first back surface wire 6bc different from the first wire 6ab. [Selection diagram] Fig. 1

Description

The present invention relates to a coil structure.

Bonding wires are equivalently represented by coils. For example, Patent Document 1 describes two wires connected in series and an equivalent circuit (T-type equivalent circuit) thereof. That is, the two wires 120 and 130 described in Patent Document 1 are relayed by the electrodes 111, and are represented by equivalent circuits of inductances L1 and L2.

Japanese Unexamined Patent Publication No. 2005-203784 (FIGS. 1, 2, paragraph 0013)

The technique described in Patent Document 1 is intended to form artificial peaking, improve transmission characteristics, and minimize return loss. Further, the two wires described in Patent Document 1 are linearly connected in series and are not wound. That is, the two wires described in Patent Document 1 are not intended to function as a coil as a whole.

In the wire described in Patent Document 1, the length of the first wire is set to 0.3 mm (inductance: 0.5 nH or less), and the length of the second wire is set to 1 to 2 mm. There is. That is, since the second wire is longer than the first wire, it may be difficult to mechanically hold it due to vibration or the like.

The present invention has been made in view of such circumstances, and an object of the present invention is to form a wound coil structure by using a bonding wire.

In order to achieve the above object , the first invention relates to a substrate (1) , a plurality of surface pads (3, 4) formed on the surface of the substrate, and a surface wire (5) connecting adjacent surface pads to each other. , 9) , a coil structure (12) having a plurality of back surface pads formed on the back surface of the substrate, and a back surface wire connecting adjacent back surface pads, wherein the front surface pad and the back surface pad are , The front and back surfaces of the substrate are arranged at the same position, and the front surface coil is formed by arranging the conductor portion including the front surface pad and the surface wire so as to form a first spiral. The back surface coil is formed symmetrically with the front surface coil by arranging the conductor portion including the back surface wire so as to form a second vortex having the same shape as the first vortex. The second vortex has a rectangular shape having a plurality of sides, and at least in the middle of the outermost side, a relay pad (3ca, 3ba, 3ab, 3ac, 3bd, 3cd, 3dc, 4ca, 4ba, 4ab, 4ac, 4bd, 4cd, 4dc) are formed. The symbols and characters in parentheses are the symbols and the like attached in the embodiments, and do not limit the present invention.

The second invention is a coil structure having a plurality of substrates laminated in a separated state, a plurality of pads formed on at least one surface of each substrate, and a wire connecting the adjacent pads. The arrangement of the pads on each substrate is the same, and in each substrate, the conductor portion including the pads and the wires is arranged so as to form a spiral in the same rotation direction, and the spiral includes a plurality of sides. It has a rectangular shape, and is characterized in that a relay pad that relays the wire is formed at least in the middle of the outermost peripheral side. In addition, it is also possible to metal-bond the end portion to the pad in a state where a plurality of ribbons are superimposed.

According to the present invention, a wound coil can be formed by using a bonding wire.

(A) is a cross-sectional view of a coil according to the first embodiment of the present invention, (b) is a perspective view seen from diagonally above, and (c) is a perspective view seen from diagonally below. .. It is a three-dimensional connection diagram of the coil which is 1st Embodiment of this invention. (A) to (c) are perspective views which show the manufacturing process of the coil of the 2nd Embodiment of this invention. (A) is a perspective view of the coil according to the third embodiment of the present invention seen from diagonally above, and (b) is a perspective view seen from diagonally below. It is a three-dimensional wiring diagram of the coil which is the 3rd Embodiment of this invention. It is a three-dimensional wiring diagram which shows the coil of the modification of the 3rd Embodiment of this invention. It is a photograph which shows the state which performed the ribbon bonding which is the bonding structure of 4th Embodiment of this invention. It is a joining structure of the reference example of the 4th Embodiment of this invention, and is a photograph which shows the joining structure which joined using one ribbon.

Hereinafter, embodiments of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings. It should be noted that each figure is merely shown schematically to the extent that the present embodiment can be fully understood. Further, in each figure, common components and similar components are designated by the same reference numerals, and duplicate description thereof will be omitted.

(First Embodiment)
1 (a) is a cross-sectional view of a coil according to the first embodiment of the present invention, FIG. 1 (b) is a perspective view also seen from diagonally above, and FIG. 1 (c) is also an oblique view. It is a perspective view seen from the bottom (the perspective view seen from the back side). The directions of X, Y, and Z follow the arrows.
In FIG. 1A, the coil 10 includes a substrate 1, a plurality of front surface pads 3, a plurality of back surface pads 4, a plurality of through conductors 2 for conducting the front surface pads 3 and the back surface pads 4, and a front surface pad 3. A plurality of metal wires 6 for conducting each other and the back surface pads 4 are provided. The front surface pad 3, the back surface pad 4, and the through conductor 2 form a through electrode.

In FIG. 1 (b), on the surface side of the coil 10, a plurality of surface pads 3 (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h) and a plurality of metal wires 6 (6ab, 6cd, 6ef) are provided. , 6gh) and are arranged. The metal wire 6 is a gold or aluminum conductor having a circular cross section. The surface pad 3 and the metal wire 6 are metal-bonded to each other by wire bonding. The plurality of surface pads 3 are two-dimensionally arranged in two columns and a plurality of rows. In the following, in FIG. 1B, the surface pads 3 in the left column are referred to as first surface pads 3a, 3c, 3e, 3g, and the surface pads 3 in the right column are referred to as second surface pads 3b, 3d, 3f, 3h. Sometimes referred to. Further, the metal wires 6 connecting the surface pads 3 on the surface side of the substrate 1 may be referred to as surface metal wires 6ab, 6cd, 6ef, 6gh.

The surface metal wires 6ab, 6cd, 6ef, and 6gh connect the left and right surface pads 3 and 3 on the surface of the substrate 1. Specifically, the first surface metal wire 6ab from the front is the first surface pad 3a and the second row (FIG. 1 (b)) from the front in the first row (left column in FIG. 1 (b)). Then, connect between the second surface pad 3b, which is the first from the front in the right column). The second surface metal wire 6cd connects between the first surface pad 3c, which is the second from the front in the first row, and the second surface pad 3d, which is the second from the front in the second row. The third surface metal wire 6ef connects between the first surface pad 3e, which is the third from the front in the first row, and the second surface pad 3f, which is the third in front of the second row. The fourth surface metal wire 6gh connects between the first surface pad 3g, which is the fourth from the front of the first row, and the second surface pad 3h, which is the fourth from the front of the second row. That is, on the surface of the substrate 1, the nth metal wire 6 from the front connects the first surface pad 3 nth from the front in the first row and the second surface pad 3 nth from the front in the second row. ..

In FIG. 1 (c), on the back surface side of the coil 10, a plurality of back surface pads 4 (4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h) and a plurality of metal wires 6 (6bc, 6de, 6fg) ) And are arranged. The back surface pad 4 and the metal wire 6 are metal-bonded to each other by wire bonding. In the following, in FIG. 1C, the back surface pad 4 in the right column may be referred to as a first back surface pad 4c, 4e, 4g, and the back surface pad 4 in the left column may be referred to as a second back surface pad 4b, 4d, 4f. .. Further, the metal wires 6 connecting the back surface pads 4 to each other on the back surface side of the substrate 1 may be referred to as back surface metal wires 6bc, 6de, 6fg.

The back surface metal wires 6bc, 6de, 6fg connect the left and right back surface pads 4 and 4 on the back surface of 1 of the substrate. Specifically, the back metal wire 6bc, which is the first from the front, is the first from the front in the second row (the row on the same side as the second row on the surface of the substrate 1 and the left row in FIG. 1C). Between the 2nd back surface pad 4b and the 1st row (the row on the same side as the 1st row on the front surface of the substrate 1 and the right row in FIG. 1C), which is the second back surface pad 4c from the front. To connect. The second back surface metal wire 6de connects between the second back surface pad 4d, which is the second from the front in the second row, and the first back surface pad 4e, which is the third from the front in the first row. The third back surface metal wire 6fg connects between the second back surface pad 4f, which is the third from the front of the second row, and the first back surface pad 4g, which is the fourth from the front of the first row. That is, on the back surface of the substrate 1, the nth metal wire 6 from the front connects the second back surface pad 4 nth from the front of the second row and the first back surface pad 4 (n + 1) th from the front of the first row. I'm out. It should be noted that two of the plurality of back surface pads 4 (in the present embodiment, the first back surface pad 4a from the front of the second row and the fourth back surface pad 4h from the front of the first row) are externally attached. The metal wires 6a and 6h to be connected are connected.

FIG. 2 is a three-dimensional connection diagram of the coil according to the first embodiment of the present invention, and shows the winding state of the coil 10 shown in FIGS. 1 (a), (b) and (c).
The coil 10 is configured by spirally winding the metal wire 6 a plurality of times (three times or more). That is, the front surface pad 3 (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h) and the back surface pad 4 (4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h) are the through conductor 2 Are connected to each other via. Further, the first surface pads 3a, 3c, 3e, 3g in the first row and the second surface pads 3b, 3d, 3f, 3h in the second row are connected via a metal wire 6. Further, the first back surface pads 4c, 4e, 4g in the first row and the second back surface pads 4b, 4d, 4f in the second row are connected. That is, the coil 10 uses the through conductor 2 and the metal wire 6 to form the first back surface pad 4a-the first front surface pad 3a-the second front surface pad 3b-the second back surface pad 4b-the first back surface pad 4c-1. Front surface pad 3c-Second front surface pad 3d-Second back surface pad 4d-First back surface pad 4e-First front surface pad 3e-Second front surface pad 3f-Second back surface pad 4f-First back surface pad 4g-First front surface pad It is formed by connecting 3 g-2nd front surface pad 3h-2nd back surface pad 4h in order. The coil 10 requires two or more metal wires 6 and two or more through conductors 2 in order to wind the conductor portion one or more times.

(Production method)
Hereinafter, a method for manufacturing the coil 10 will be briefly described.
The front surface pad 3 and the back surface pad 4 are formed on the substrate 1, and the through conductor 2 is formed. Next, the metal wire 6 is bonded to the front surface pad 3 of the substrate 1, and the metal wire 6 is bonded to the back surface pad 4. When bonding the metal wire 6 to the back surface pad 4, a jig (work holder) having a mechanism (for example, counterbore) for the wire 6 bonded to the front surface pad 3 to escape is used.

As described above, according to the coil 10 of the present embodiment, the metal wire is wound by a plurality of turns (for example, 4 turns) by using wire bonding. That is, according to the coil 10 of the present embodiment, a spiral conductor (a spiral conductor in which a through conductor 2, a front surface pad 3, a back surface pad 4 and a metal wire 6 are connected between the back surface pads 4a and 4h for input / output terminals). A three-dimensional coil) can be formed. Here, if the lengths of the plurality of metal wires 6 (6ab, 6cd, 6ef, 6gh, 6ab, 6cd, 6ef, 6gh) are minimized, a coil that is mechanically strong against vibration can be obtained.

(Second Embodiment)
The coil 10 of the first embodiment uses the back surface pad 4, but as shown in the perspective view of FIG. 3 (c), the coil 10 may be wound a plurality of times only by the front surface pad 3. can.

FIG. 3 is a perspective view showing the manufacturing process of the coil according to the second embodiment of the present invention, and FIG. 3 (c) is a perspective view showing a state at the final stage.
The coil 11 of the second embodiment includes a substrate 1, a plurality of surface pads 3 (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h), and a plurality of surface pads 3 conducting each other on the surface of the substrate 1. 8 (8ab, 8cd, 8ef, 8gh), the insulating member 7 arranged on the connecting wire 8, and a plurality of metal wires 6 (6ad, 6ad,) for conducting the surface pads 3 across the insulating member 7. 6cf, 6eh) and.

The plurality of surface pads 3 (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h) are arranged in two columns and a plurality of rows (in the embodiment, two columns and four rows) as in the first embodiment. To. Here, as in the first embodiment, the surface pads 3 in the left column are referred to as the first surface pads 3a, 3c, 3e, 3g, and the surface pads 3 in the right column are referred to as the second surface pads 3b, 3d, 3f. It is called 3h.

The connecting line 8 (8ab, 8cd, 8ef, 8gh) has the first surface pad 3 (3a, 3c, 3e, 3g) and the second surface pad 3 (3b, 3d, 3f, 3b, 3d, 3f, in the same row, m rows and n columns. Connect with 3h). That is, the connection line 8ab connects the first surface pad 3a and the second surface pad 3b. The connection line 8cd connects the first surface pad 3c and the second surface pad 3d. The connection line 8ef connects the first surface pad 3e and the second surface pad 3f. The connection line 8gh connects the first surface pad 3g and the second surface pad 3h. The first surface pad 3 (3a, 3c, 3e, 3g), the second surface pad 3 (3b, 3d, 3f, 3h) in the same row, and the connecting line 8 (8ab, 8cd, 8ef) connecting them. , 8gh), and is referred to as a connecting pad.

Here, the plurality of connecting lines 8ab, 8cd, 8ef, 8gh of the coil 11 of the present embodiment are arranged in parallel and at equal intervals. Although the back surface pad 4 (FIG. 1 (a)) is not formed in the present embodiment, the back surface pad 4 may be formed. Only the metal wire is not joined to the back pad 4.

The metal wire 6 (6ad, 6cf, 6eh) connects the first surface pad 3 (3a, 3c, 3e) to the second surface pad 3 (3d, 3f, 3h) in a different row. That is, the metal wire 6ad connects the first surface pad 3a and the second surface pad 3d. The metal wire 6cf connects the first surface pad 3c and the second surface pad 3f. The metal wire 6eh connects the first surface pad 3e and the second surface pad 3h. As a result, the coil 11 is formed. A metal wire 6g connected to the outside is connected to the first surface pad 3g, and a metal wire 6b connected to the outside is connected to the second surface pad 3b.

The insulating member 7 has a rectangular parallelepiped shape, straddles a plurality of connecting lines 8ab, 8cd, 8ef, 8gh, has a plurality of connecting lines 8ab, 8cd, 8ef, 8gh, and a plurality of metal wires 6 (6ab, 6cd, 6ef, 6gh). , 6ab, 6cd, 6ef, 6gh). Although the insulating member 7 has a rectangular parallelepiped shape, it may be cylindrical.

The coil 11 of the present embodiment has a second surface pad 3b-connecting wire 8ab-first surface pad 3a-metal wire 6ad-second surface pad 3d-connecting wire 8cd-first surface pad 3c-metal wire 6cf-2nd. The surface pad 3f-connecting wire 8ef-first surface pad 3e-metal wire 6eh-second surface pad 3h-connecting wire 8gh-first surface pad 3g are connected and configured. That is, the coil 11 is formed of a spiral conductor composed of a connecting wire 8, a metal wire 6, and a surface pad 3. The coil 11 requires two or more metal wires 6 and two or more connecting wires 8 in order to wind the conductor portion one or more times.

Even if the metal wires 6ad, 6cf, 6heh are long, the metal wires 6ad, 6cf, 6heh are stably held against vibration if they are brought into contact with the upper surface 7a of the insulating member 7 at the central portion. Further, the distance (distance in the Z direction) between the metal wires 6ad, 6cf, 6eh and the connecting wires 8ab, 8cd, 8ef, 8gh is defined by the height of the insulating member 7. Therefore, the capacitance (parasitic capacitance) between the metal wires 6ad, 6cf, 6eh and the connecting wires 8ab, 8cd, 8ef, 8gh becomes small, and at the same time, the variation becomes small.

(Production method)
In step SP1 of FIG. 3A, a plurality of surface pads 3 (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h) and a plurality of connection lines 8 (8ab, 8cd,) are formed on the upper surface of the substrate 1. 8ef, 8gh) are simultaneously formed with the same metal by etching. As a result, the first surface pad and the second surface pad are connected to each other with the same metal as a connecting pad. The plurality of connecting lines 8ab, 8cd, 8ef, 8gh do not have to be formed simultaneously with the plurality of surface pads 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h.

In step SP2 of FIG. 3B, the rod-shaped insulating member 7 is arranged on the plurality of connecting lines 8ab, 8cd, 8ef, 8gh. Further, the insulating member 7 is arranged at the center of the first surface pads 3a, 3c, 3e, 3g and the second surface pads 3b, 3d, 3f, 3h.

In step SP3 of FIG. 3C, a plurality of metal wires 6ad, 6cf, 6heh are metal-bonded to the plurality of first surface pads 3a, 3c, 3e and the second surface pads 3d, 3f, 3h.

(Modified example of the second embodiment)
In the coil 11, the first surface pads 3a, 3c, 3e, 3g and the second surface pads 3d, 3f, 3h in the same row are connected by connecting wires 8ab, 8cd, 8ef, 8gh, and the first surface pads 3a, 3c, 3e and the second surface pads 3d, 3f, 3h in different rows were connected by metal wires 6ad, 6cf, 6heh. The first surface pads 3a, 3c, 3e, 3g and the second surface pads 3d, 3f, 3h in the same row are connected by a metal wire 6, and the first surface pads 3a, 3c, 3e and the second in a different row are connected. The surface pads 3d, 3f, and 3h may be connected by the connection line 8.

(Third Embodiment)
In the first and second embodiments, the spiral coils 10 and 11 are formed, but spiral coils may be formed on at least one of the front surface and the back surface of the substrate 1.

FIG. 4A is a perspective view of the coil 12, which is the third embodiment of the present invention, as seen from diagonally above, and FIG. 4B is a perspective view of the coil 12 as viewed from diagonally below. The arrows X, Y, and Z in the figure indicate the direction of each side of the substrate 1. The coil 12 includes a front surface coil 12a formed on the front surface side of the substrate 1 and a back surface coil 12b formed on the back surface side of the substrate 1. The front surface coil 12a and the back surface coil 12b are front and back symmetry (plane symmetry), and as shown in FIG. 5, the front surface coil 12a and the back surface coil 12b are overlapped (stacked).

In the surface side perspective view of FIG. 4A, the surface coil 12a is the substrate 1 and a plurality of surface pads 3 (3aa, 3aa, which are two-dimensionally arranged in m rows and n columns (for example, a square matrix of 4 rows and 4 columns). 3ba, 3ca, 3da, 3ab, 3bb, 3cab, 3cd, 3ac, 3bc, 3cc, 3dc, 3ad, 3bd, 3cd, 3dd) and a plurality of metal wires 5 (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l, 5m, 5n, 5o).

The metal wires 5a to 5k connect adjacent surface pads (3da, 3ca, ... 3db) on the outermost circumference (first round counting from the outside) among the plurality of two-dimensionally arranged surface pads 3. There is. The metal wire 5l connects the surface pad 3db on the first lap and the surface pad 3kb on the second lap counting from the outside, and the metal wires 5m to 5o are adjacent surface pads on the second lap counting from the outside (the metal wire 5l). 3cc, ... 3cc) are connected to each other. Metal wires 5x and 5y connected to the outside are connected to the surface pads 3cc and 3da.

As a result, the plurality of metal wires 5 (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l, 5m, 5n, 5o) are connected via the surface pad 3. The surface coil 12a is configured.

In the back side perspective view of FIG. 4 (b), the back surface coil 12b includes the substrate 1 and a plurality of back surface pads 4 (4aa, 4ba, 4ca, 4da, 4ab, 4bb, 4cc) two-dimensionally arranged in m rows and n columns. , 4cd, 4ac, 4bc, 4cc, 4dc, 4ad, 4bd, 4cd, 4dd) and multiple metal wires 9 (9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i, 9j, 9k, 9l). , 9m, 9n, 9o). Metal wires 5x and 5y connected to the outside are connected to the surface pads 3cc and 3da.

The metal wires 9a to 9k connect the backside pads (4da, 4ca, ... 4db) adjacent to each other on the outermost circumference (the first lap counting from the outside) among the plurality of backside pads 4 arranged two-dimensionally. There is. The metal wire 9l connects the back surface pad 4db on the first lap and the back surface pad 4kb on the second lap counting from the outside, and the metal wires 9m to 9o are adjacent backside pads on the second lap counting from the outside (the metal wire 9l). 4cc, ..., 4cc) are connected to each other. The metal wires 4x and 4y connected to the outside are connected to the back surface pads 4cc and 4da.

As a result, the plurality of metal wires 9 (9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i, 9j, 9k, 9l, 9m, 9n, 9o) are connected via the back surface pad 4. It constitutes the back surface coil 12b.

FIG. 5 is a three-dimensional wiring diagram of the coil 12 according to the third embodiment of the present invention. Here, the black circles are the front pad 3 (3aa, 3ba, 3ca, 3da, 3ab, 3bb, 3cab, 3cd, 3ac, 3bc, 3cc, 3dc, 3ad, 3bd, 3cd, 3dd) and the back pad 4 (4aa, 4ba). , 4ca, 4da, 4ab, 4bb, 4cab, 4cd, 4ac, 4bc, 4cc, 4dc, 4ad, 4bd, 4cd, 4dd) are expressed. The shape of the conductor portion of the back surface coil 12b is substantially the same as the shape of the conductor portion of the front surface coil 12a.

In the coil 12, the front surface coil 12a having the self-inductance La and the back surface coil 12b having the self-inductance Lb are arranged symmetrically on the front and back sides (plane symmetry). Therefore, a mutual inductance M exists between the front surface coil 12a and the back surface coil 12b. The combined inductance L when one end of the front coil 12a and one end of the back coil 12b are connected is L = (La + Lb + 2M) when the currents Ia and Ib are passed in the same direction (Ia = Ib). Further, when the currents Ia and Ib are passed in the opposite direction (Ia = −Ib), L = (La + Lb-2M).

Here, when the current is passed in the same direction, for example, the metal wire 5y and the metal wire 4x are connected, or the metal wire 5x and the metal wire 4y are connected. On the other hand, when a current is passed in the opposite direction, for example, the metal wire 4y and the metal wire 5y (FIG. 4) are connected, or the metal wire 4x and the metal wire 4x (FIG. 4) are connected. Is. Further, if the front coil 12a and the back coil 12b have the same length and shape and are arranged close to each other, La≈Lb≈M, and the combined inductance L is L≈4La.

(Modified example of the third embodiment)
In the coil 12 of the third embodiment, the two front coil 12a and the back coil 12b having the same shape are arranged symmetrically, but three or more coils having the same shape can be overlapped.

FIG. 6 is a three-dimensional wiring diagram showing a coil of a modified example of the third embodiment of the present invention.
The coil 13 has a front surface coil 12a, a back surface coil 12b, and a coil 12c arranged in a three-layer structure having the same shape. Here, the front surface coil 12a and the back surface coil 12b can be formed on the front and back surfaces of the substrate 1 in the same manner as the coil 12 of the third embodiment. However, the third layer coil 12c will be formed on a substrate other than the substrate 1. Then, the coil 13 is created by arranging the substrate 1 on which the front surface coil 12a and the back surface coil 12b are formed and another substrate on which the coil 12c is formed. Here, as the coil 13, three substrates 1 may be prepared, a coil may be formed on each of the substrates 1, and the substrates 1 on which the coils are formed may be arranged side by side.

The front surface coil 12a has a self-inductance La, the back surface coil 12b has a self-inductance Lb, and the coil 12c has a self-inductance Lc. Further, a mutual inductance Mab exists between the front surface coil 12a and the back surface coil 12b, a mutual inductance Mbc exists between the back surface coil 12b and the coil 12c, and a mutual inductance Mbc exists between the coil 12c and the front surface coil 12a. Has a mutual inductance Mca.

(Fourth Embodiment)
In the first to third embodiments, a wire (conductor) having a circular cross section is bonded to a pad (front pad 3 or back pad 4) formed on the substrate 1, but a plate-shaped ribbon is used as a wire. It can also be bonded.

FIG. 7 is a photograph of ribbon bonding, which is the bonding structure of the fourth embodiment of the present invention.

In the bonding structure of the present embodiment, ribbon bonding is performed in a state where a plurality of ribbons 80, 80, ..., 80 are stacked. The ribbon 80 is a metal wire made of a rectangular plate material of aluminum or gold having joints 80a formed at both ends. The ribbon size is, for example, width 0.05 × thickness 0.02 mm to width 0.3 × thickness 0.03 mm. Since the ribbon 80 is thin, it bends. The ribbon 80 can carry a larger current than the metal wires 6 (FIG. 1) and 5 and 9 (FIG. 4) having a circular cross section if the flexibility is the same.

In FIG. 7, the electrode pad 70 provided on the substrate (including the substrate 1 described above) and the plurality of bonding portions 80a are metal-bonded by bonding. The bonding portion 80a is a portion for metal bonding with an electrode pad 70 formed on a semiconductor element (for example, a power semiconductor) by bonding.

FIG. 8 is a photograph of ribbon bonding, which is a bonding structure of a reference example of the fourth embodiment of the present invention. The joining structure of this reference example is one in which the joining portion 80a is joined to the electrode pad 70 by using one ribbon 80. The electrode pad 70 may be the electrode pad (front surface pad 3 or back surface pad 4) of each of the above-described embodiments.

On the other hand, in the joining structure of the fourth embodiment, since a plurality of ribbons 80, 80, ... 80 are connected in parallel, a larger current flows than when one ribbon 80 is used. be able to. Further, if the flowing currents are the same, the combined resistance value is small, so that the voltage drop across the ribbon 80 is reduced. That is, according to the joining structure of the present embodiment, it is possible to provide a joining structure in which an electric current can easily flow as compared with using one ribbon 80.

1 Substrate 2 Through Conductor (Through Silicon Via)
3,3aa, 3ba, 3ca, 3da, 3ab, 3bb, 3cab, 3db, 3ac, 3bc, 3cc, 3dc, 3ad, 3bd, 3cd, 3dd Surface Pad (Through Silicon Via)
3a, 3c, 3e, 3g 1st surface pad 3b, 3d, 3f, 3h 2nd surface pad 4,4aa, 4ba, 4ca, 4da, 4ab, 4bb, 4cc, 4db, 4ac, 4bc, 4cc, 4dc, 4ad, 4bd, 4cd, 4dd Back side pad (through electrode)
4c, 4e, 4g 1st back pad 4b, 4d, 4f 2nd back pad 5,5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l, 5m, 5n, 5o Metal Wire (surface wire)
6,6a, 6h, 6ad, 6cf, 6eh, 6b, 6g Metal wire 6ab, 6cd, 6ef, 6gh Front surface metal wire 6bc, 6de, 6fg Back surface metal wire 9, 9a, 9b, 9c, 9d, 9e, 9f, 9g , 9h, 9i, 9j, 9k, 9l, 9m, 9n, 9o Metal wire (back surface wire)
7 Insulation member 8,8ab, 8cd, 8ef Connection line 10,11,12,12c, 13 Coil 12a Front coil 12b Backside coil 50 Metal wire 70 Electrode pad 80 Ribbon 80a Joint

Claims (3)

A substrate, a plurality of front surface pads formed on the front surface of the substrate, a front surface wire connecting adjacent front surface pads, a plurality of back surface pads formed on the back surface of the substrate, and adjacent back surface pads. A coil structure having a back wire to be connected.
The front surface pad and the back surface pad are arranged at the same positions on the front and back surfaces of the substrate.
A surface coil is formed by arranging the conductor portion including the surface pad and the surface wire so as to form a first spiral.
The back surface coil is formed symmetrically with the front surface coil by arranging the conductor portion including the back surface pad and the back surface wire so as to form a second spiral having the same shape as the first spiral.
The first vortex and the second vortex have a rectangular shape having a plurality of sides and have a rectangular shape.
A coil structure characterized in that a relay pad for relaying a wire is formed at least in the middle of the outermost peripheral side. The coil structure according to claim 1 , wherein the front surface coil and the back surface coil are connected so that currents flow in the same directions on the front and back surfaces. A coil structure having a plurality of substrates laminated in a separated state, a plurality of pads formed on at least one surface of each substrate, and a wire connecting the adjacent pads.
The arrangement of the pads on each substrate is the same,
In each of the substrates, the conductor portion including the pad and the wire is arranged so as to form a spiral in the same rotation direction.
The swirl is rectangular with a plurality of sides and has a rectangular shape.
A coil structure characterized in that a relay pad for relaying the wire is formed at least in the middle of the outermost peripheral side.

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