JP2008140962A - Electronic board, method of using the same, and electronic device - Google Patents

Abstract

An electronic substrate, a method of using the electronic substrate, and an electronic device capable of improving electrical characteristics, improving heat dissipation characteristics, and suppressing energy loss of an inductor element.
A plurality of first wirings 12 formed on a substrate 10, an insulating layer (second magnetic layer 31) continuously formed so as to cover a central portion of the plurality of first wirings 12, and an insulating layer A plurality of second wirings 22 formed so as to cross the surface, and the second wiring 122 is an end portion of one of the first wirings 113 and another first wiring not adjacent to the first wiring 113. The inductor element 40 includes a plurality of windings 141 and 241 including the first wiring 12 and the second wiring 22, and a plurality of windings 141. , 241 are connected to different electrodes 111, 121 and 211, 221, respectively, and different signals (currents I ₁ , I ₂ ) flow alternately through the adjacent windings 141, 241.
[Selection] Figure 2

Description

  The present invention relates to an electronic substrate, a method for using the same, and an electronic apparatus.

An electronic substrate (semiconductor chip) on which an electronic circuit is formed is mounted on an electronic device such as a mobile phone or a personal computer. This electronic substrate may be used together with passive elements such as resistors, inductor elements, and capacitors. Patent Documents 1 and 2 propose a technique for forming a spiral inductor element on an electronic substrate. The spiral inductor element has a spiral winding formed on the surface of a base serving as a core. Non-Patent Document 1 proposes a technique for forming a toroidal inductor element on an electronic substrate. In the toroidal inductor element, a spiral winding is formed around a ring-shaped core.
JP 2002-164468 A JP 2003-347410 A Ermolov et al, (Microreplicated RF Toroidal Inductor), IEEE Transactions on Microwave Theory and Technologies, Vol. 52, no. 1, January 2004, p29-36

However, since leakage current is generated due to interference between the magnetic flux generated in the inductor element and silicon constituting the electronic substrate, there is a problem that there is a limit in improving the Q value (ratio between the inductance and the resistance value) of the inductor element. .
Recently, it has been studied to cause an inductor element formed on an electronic substrate or a semiconductor chip to function as a part of a power supply circuit such as a choke coil or a transformer. In this case, it is essential to improve the inductance value of the inductor element. However, the improvement of the inductance value of the inductor element is accompanied by an increase in the number of windings of the inductor element, and heat is also generated because a large amount of current flows. Therefore, suppression of the enlargement of an electronic substrate and suppression of a temperature rise are desired.
In addition, when a high-frequency AC voltage is applied to the inductor element, part of the energy applied to the inductor element is changed to thermal energy in the core and the substrate, and the core and the substrate temperature are increased, resulting in an energy loss. . As a result, there is a problem that there is a limit to improvement of electrical characteristics such as inductance.

  The present invention has been made to solve the above-described problem, and an electronic substrate capable of improving electrical characteristics, improving heat dissipation characteristics, and suppressing energy loss of inductor elements, and a method of using the same And to provide electronic equipment.

In order to achieve the above object, an electronic substrate according to the present invention is an electronic substrate including an inductor element on a substrate, and includes a plurality of first wirings formed on the substrate, and the plurality of first wirings. An insulating layer continuously formed so as to cover a central portion; and a plurality of second wirings formed so as to cross a surface of the insulating layer, wherein the second wiring is an end of the first wiring. And the end of the other first wiring not adjacent to the first first wiring are sequentially connected, and the inductor element includes a plurality of the first wiring and the second wiring. The plurality of windings are connected to different electrodes, respectively, and different signals alternately flow through the adjacent windings.
According to this configuration, a plurality of windings can be alternately arranged, and the winding density can be improved. As a result, the magnetic flux density can be increased, and the inductance value and Q value of the inductor element can be improved. Therefore, the electrical characteristics of the electronic substrate can be improved.
Further, different signals flow alternately from the different electrodes connected to the respective windings to the respective windings, thereby canceling the magnetic fields generated by the mutual windings. Therefore, especially when supplying a high-frequency alternating current, the movement of the dipole accompanying the fluctuation of the winding magnetic field in the substrate is suppressed, the thermal energy consumed by the substrate is reduced, and the energy loss of the inductor element is suppressed. be able to. Further, it is possible to prevent the generation of eddy currents in the substrate and the conductor, and to suppress the energy loss of the inductor element due to the eddy current loss.

The insulating layer is preferably a magnetic layer having at least a surface insulated.
According to this configuration, since the magnetic flux density of the winding is improved, the inductance value and Q value of the inductor element can be improved. Therefore, the electrical characteristics of the electronic substrate can be improved.

Further, the inductor element may include two windings, and an alternating current having the same frequency may be supplied from each electrode to each winding in a state where the phases are different by 180 °.
According to this configuration, since currents in opposite directions flow through the windings, the magnetic fields generated by the windings can be offset. Therefore, particularly when a high-frequency alternating current is supplied, heat loss due to dipole motion on the substrate can be minimized, and energy loss of the inductor element can be minimized. Further, it is possible to prevent the generation of eddy currents in the substrate and the conductor, and to suppress the energy loss of the inductor element due to the eddy current loss.

The inductor element may include three windings, and an alternating current having the same frequency may be supplied from each electrode to each winding in a state in which the phases are different by 120 °.
According to this configuration, since the current direction of one of the three windings and the current of the other two windings flow in opposite directions, the magnetic field generated by one winding is different from the other. Can be canceled by the magnetic field generated by the second winding. Therefore, particularly when supplying a high-frequency alternating current, it is possible to minimize the heat loss due to the movement of the dipole in the substrate and to suppress the energy loss of the inductor element. Further, it is possible to prevent the generation of eddy currents in the substrate and the conductor, and to suppress the energy loss of the inductor element due to the eddy current loss.

In addition, a gap between adjacent windings may be filled with a nonmagnetic material, and the periphery of the inductor element may be covered with a magnetic material.
According to this configuration, since the closed magnetic circuit is formed by the magnetic material, the magnetic flux density can be further increased, and the inductance value and Q value of the inductor element can be further improved.

Moreover, it is desirable that all or part of the periphery of the substrate is covered with a heat dissipation member made of a material having a higher thermal conductivity than the substrate.
According to this configuration, it is possible to quickly release the heat generated in the electronic substrate to the outside.
Therefore, the temperature rise of the electronic substrate can be suppressed.

Further, it is desirable that the heat dissipating member is fixed to the substrate via an adhesive in which metal fine particles are dispersed.
Dispersing the metal fine particles increases the thermal conductivity of the adhesive, so that the heat generated in the electronic substrate can be quickly released to the outside. Therefore, the temperature rise of the electronic substrate can be suppressed.

On the other hand, the method of using the electronic substrate according to the present invention includes a plurality of first wirings formed on the substrate, an insulating layer continuously formed so as to cover a central portion of the plurality of first wirings, and the insulating layer. A plurality of second wirings formed so as to cross the surface of the first wiring, and the second wiring includes an end portion of the first wiring and the other first wiring not adjacent to the first wiring. The wiring ends are arranged in order to be connected to each other, and include a plurality of windings composed of the first wiring and the second wiring, and the plurality of windings are connected to different electrodes, A method of using an electronic substrate including an inductor element, wherein different signals alternately flow in adjacent windings.
According to this method, it is possible to use the electronic substrate while minimizing the energy loss of the inductor element having a plurality of windings.

On the other hand, an electronic apparatus according to the present invention includes the above-described electronic substrate.
According to this configuration, since the low-cost electronic substrate having excellent electrical characteristics and low energy loss is provided, a low-cost electronic device having excellent electrical characteristics and high energy efficiency can be provided.

Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.
(First embodiment)
FIG. 1 is an explanatory view of an electronic substrate, FIG. 1 (a) is a plan view, and FIG. 1 (b) is a side sectional view taken along line BB of FIG. 1 (a). In FIG. 1A, description of a solder resist and a heat radiating member, which will be described later, is omitted. As shown in FIG. 1A, the electronic substrate 1 according to the present embodiment is a bare chip of an integrated circuit such as an IC or LSI, and includes an inductor element 40 on the surface of the substrate 10.

As shown in FIG. 1B, the electronic substrate 1 includes a substrate 10 made of silicon, glass, quartz, crystal, or the like. An electronic circuit (not shown) is formed on the surface of the substrate 10.
In the electronic circuit, at least a wiring pattern is formed, semiconductor elements such as a plurality of passive components (components), a plurality of transistors, and a plurality of thin film transistors (TFTs), wirings interconnecting them, and the like It is constituted by. In order to protect the electronic circuit, a passivation film 8 made of an electrically insulating material such as SiN is formed on the surface of the substrate 10. On the other hand, an electrode 62 for electrically connecting the electronic circuit to the outside is formed on the peripheral edge portion and the central portion of the surface of the substrate 10. An opening of the passivation film 8 is formed on the surface of the electrode 62.

(Inductor element)
2A and 2B are explanatory diagrams of the inductor element, FIG. 2A is a plan view, and FIG. 2B is a side cross-sectional view taken along the line CC in FIG. 2A. FIG. 3 is a side sectional view taken along the line DD in FIG. In FIG. 2A, descriptions of a solder resist and a heat radiating member, which will be described later, are omitted. In FIG. 2A, the upper side of the paper surface is the + Y direction, and the right side of the paper surface is the + X direction.
The inductor element 40 traverses the surface of the line-shaped second magnetic layer 31, the plurality of first wirings 12 disposed so as to traverse the back surface of the second magnetic layer 31, and the second magnetic layer 31. A plurality of second wirings 22 are arranged, and a spiral winding 41 is formed by the first wiring 12 and the second wiring 22. The inductor element 40 is formed by arranging the first winding 141 on the primary side and the second winding 241 on the secondary side around the core 42 made of the second magnetic layer 31. The periphery of the inductor element 40 is covered with a magnetic material 43 to form a closed magnetic circuit. As described above, if a magnetic material is used for the core 42, the performance as an inductor (inductance value) is greatly improved because the magnetic flux density is improved. A formed insulating layer may be used.

A first magnetic layer 43 a is formed of a magnetic material 43 in the formation region of the inductor element 40 on the surface of the passivation film 8. Here, as the magnetic material 43, for example, ferrite or the like is used similarly to the second magnetic layer described later.
The first wiring 12 is formed on the surface of the first magnetic layer 43a. The first wiring 12 includes copper (Cu), gold (Au), silver (Ag), titanium (Ti), tungsten (W), titanium tungsten (TiW), titanium nitride (TiN), nickel (Ni), nickel It is made of a conductive material such as vanadium (NiV), chromium (Cr), aluminum (Al), or palladium (Pd). It should be noted that the constituent material of the first wiring 12 can be appropriately selected according to characteristics such as a resistance range necessary for the winding of the inductor element 40 and an allowable current value. In the case where the first wiring 12 is formed by electrolytic plating, the first wiring 12 is formed on the surface of the underlayer, but the description of the underlayer is omitted in FIG.

The first wiring 12 is patterned into a substantially parallelogram shape, and a plurality of first wirings 12 are arranged substantially in parallel. The space between the adjacent first wirings 12 is desirably formed with a constant width near the resolution limit of photolithography. Thereby, the ratio of L / S (Line and Space) of the first wiring 12 is increased, and the wiring resistance can be reduced. Of the plurality of first wirings 12, the first wiring 118 arranged at the end on the + Y side is connected to the primary electrode 111 via the connection wiring 111a, and the first wiring 218 arranged next to the first wiring 118 is connected. The secondary electrode 211 is connected to the secondary electrode 211 via the connection wiring 211a.
A space between adjacent first wirings 12 is filled with a nonmagnetic material 44, and a first nonmagnetic layer 44a is formed as shown in FIG. Here, as the nonmagnetic material 44, a photosensitive resin material such as acrylic resin, photosensitive polyimide, BCB (benzocyclobutene), phenol novolac resin, or the like is used. By using such a photosensitive resin material, patterning by photolithography can be performed.

A linear second magnetic layer 31 is formed so as to cover the central portions of the plurality of first wirings 12 and the first nonmagnetic layer 44a.
A cross section perpendicular to the extending direction of the second magnetic layer 31 is substantially semicircular. By adopting ferrite as the magnetic material constituting the second magnetic layer 31, the magnetic material can be introduced at low cost. Ferrite is a general term for complex oxides composed mainly of Fe2O3 and divalent metal oxides, and has electrical insulation. As will be described later, ferrite can be obtained by oxidizing Fe, which is a first metal, and Mn, Co, Ni, etc., which are second metals. Spinel type ferrite (MFe2O4) is a soft magnetic material, magnetoplumbite type ferrite (MFe12O19) is a permanent magnet, and garnet type ferrite (MFe5O12; M = Y, Sm, Gd, Dy, Ho, Er, Yb) is a micro material. Used as a wave material for circulators, isolators and the like. Since ferrite is an oxide and has an insulating surface, a coil pattern to be described later can be formed immediately above. When the second magnetic layer 31 is formed of a magnetic metal layer such as iron, it is preferable to perform an insulating process such as oxidizing the surface or depositing an insulating resin. Further, the magnetic layer may be an amorphous metal layer having a high magnetic permeability represented by an Fe-based material.

A second wiring 22 is formed so as to cross the surface of the second magnetic layer 31. The second wiring 22 is also formed of the same conductive material as the first wiring 12. The second wiring 22 is also patterned into a substantially parallelogram shape, and a plurality of second wirings 22 are arranged substantially in parallel. It is desirable that the space between the adjacent second wirings 22 is also formed with a constant width near the resolution limit of photolithography. Of the plurality of second wirings 22, the second wiring 128 disposed at the end portion on the −Y side is coupled to the primary electrode 121 via the coupling wiring 121 a, and the second wiring 228 disposed adjacent thereto. Is connected to the secondary electrode 221 through the connecting wiring 221a.
A space between adjacent second wirings 22 is also filled with a nonmagnetic material 44 to form a second nonmagnetic layer 44b. The end of the second nonmagnetic layer 44b is formed so as to overlap the end of the first nonmagnetic layer 44a. Thereby, the nonmagnetic material 44 is filled in all the gaps of the winding 41.

  The third magnetic layer 43b is formed of the magnetic material 43 so as to cover the plurality of second wirings 22 and the second nonmagnetic layer 44b. As the magnetic material 43, for example, ferrite or the like can be adopted in the same manner as the magnetic material constituting the second magnetic layer 31. The third magnetic layer 43b is formed so as to overlap with the peripheral edge of the first magnetic layer 43a. The third magnetic layer 43 b is formed so as to overlap both end portions of the second magnetic layer 31. Thereby, the periphery of the inductor element 40 is covered with the magnetic material 43, and a closed magnetic circuit is formed in the inductor element 40.

The plurality of second wirings 22 includes a primary side second wiring 122 and a secondary side second wiring 222.
The second wiring 122 on the primary side includes, in order, an end on the + X side of one first wiring 113 and an end on the −X side of another first wiring 114 that is not adjacent to the first wiring 113. It is arranged to be connected. The first winding 141 on the primary side is formed by the second wiring 122 and the first wirings 113 and 114. The primary winding 141 on the primary side is connected to the first electrode pair 111 and 121 on the primary side.

  The second wiring 222 on the secondary side includes the + X side end of the first wiring 213 adjacent to the first wiring 113 and the other first wiring 214 not adjacent to the first wiring 213. Are arranged so as to be sequentially connected to the −X side end. These second wiring 222 and first wirings 213 and 214 form a second winding 241 on the secondary side. The secondary side second winding 241 is connected to the secondary side second electrode pair 211, 221.

  As described above, the primary winding 141 and the secondary winding 241 on the secondary side are arranged around the core of the second magnetic layer 31 to form an inductance element. Thereby, the electronic substrate of this embodiment can be utilized as an IC chip for a power supply circuit. In the present embodiment, an example in which the inductor element 40 is inserted between the electrodes has been described. However, the insertion place is built in the electronic board between the electrode and the external terminal, between the external terminal and the external terminal, or the like. Various modifications can be made to the connection destination such as between passive components. This is the same in all embodiments described later.

As described above, in the present embodiment, the second wiring is arranged so as to sequentially connect the end of one first wiring and the end of another first wiring not adjacent to the first first wiring. The inductor element including a plurality of windings composed of the first wiring and the second wiring is formed. According to this configuration, a plurality of windings can be alternately arranged, and the winding density can be improved. As a result, the magnetic flux density can be increased, and the electrical characteristics of the electronic substrate can be improved.
By configuring the core 42 of the inductor element 40 with a magnetic material, the magnetic flux density can be increased, and the L value (inductance) and Q value of the inductor element 40 can be significantly improved.
Further, the gap between the adjacent first winding 141 and second winding 241 is filled with the nonmagnetic material 44, and the periphery of the inductor element 40 is covered with the magnetic material 43, thereby forming a closed magnetic circuit in the inductor element 40. Therefore, the magnetic flux density can be further increased, and the L value and Q value of the inductor element 40 can be further improved.

  FIG. 4 is an explanatory diagram of a modified example of the electronic substrate, and is a side cross-sectional view of a portion corresponding to the line CC in FIG. In the modification shown in FIG. 4, a conductive layer (electrical shield layer) 7 is formed on substantially the entire back surface of the passivation film 8. The conductive layer 7 can be formed of a conductive material such as Al or Cu using an electronic circuit formation process. If the conductive layer 7 is held at ground or at a constant potential, the influence (coupling) of the magnetic field of the inductor element 40 on the electronic circuit including the active element of the substrate 10 can be reduced by the electromagnetic shielding effect. The conductive layer 7 may be formed at any position between the inductor element 40 and the electronic circuit. In addition, the conductive layer 7 may be formed at least in the region where the inductor element 40 is formed, even though it is not formed on the substantially entire surface of the electronic substrate. Further, the magnetic shield layer may be formed of the above-described magnetic material (ferrite, amorphous metal layer, or the like) instead of the conductive layer, which has higher magnetic shield characteristics and improved inductor characteristics. In addition, since the magnetic layer is formed around the inductor, the electrical and magnetic shield characteristics are further improved.

Here, referring again to FIG. 2, the first winding 141 and the second winding 241 are connected to different first electrode pairs 111 and 121 and second electrode pairs 211 and 221, respectively. In the inductor element 40, a power source (not shown) connected to the first electrode pair 111, 121 is different from a power source (not shown) connected to the second electrode pair 211, 221. That is, the current I ₁ can be supplied from the electrode 111 of the first electrode pair 111, 121 to the electrode 121, and the current I ₂ can be supplied from the electrode 221 of the second electrode pair 211, 221 to the electrode 211.

Thereby, at a certain point in time, the electrode 111 and the electrode 221 can be set as a positive pole, and the electrode 211 and the electrode 121 can be set as a negative pole. In this case, the direction of flow of current I ₁ supplied to the first winding 141, and the flow direction of the current I ₂ is supplied to the second winding 241 adjacent have opposite directions to each other. In this manner, different currents I ₁ and I ₂ alternately flow in the adjacent first winding 141 and second winding 241.
With this configuration, the magnetic field excited in the first winding 141 by the current I ₁ can be canceled by the reverse magnetic field excited in the second winding 241 by the current I ₂ .

At this time, the currents I ₁ and I ₂ may be supplied to the first winding 141 and the second winding 241 as alternating currents having the same frequency and different phases by 180 °. Thereby, even if the positive electrode and the negative electrode are periodically switched in the first electrode pair 111 and 121 and the second electrode pair 211 and 221, the direction in which the current I ₁ supplied to the first winding 141 flows, The direction in which the current I ₂ supplied to the two windings 241 flows can always be opposite to each other.
Therefore, even if the currents I ₁ and I ₂ are high-frequency alternating currents, the magnetic field excited in the first winding 141 by the current I ₁ is always canceled by the magnetic field excited in the second winding 241 by the current I ₂ . can do.

Here, when the alternating currents I ₁ and I ₂ having the same direction and the same period are supplied to the first winding 141 and the second winding 241 as in the prior art, they are generated in the first winding 141 and the second winding 241. A dipole due to polarization is generated in the substrate 10 or the like by the magnetic field, and the dipole changes its direction in synchronization with the change in the direction of the magnetic field. When the period of the direction change of the magnetic field is slow, the direction change of the dipole can follow this. However, as the direction change period becomes faster, the movement of the dipole gradually begins to lag due to frictional resistance. At this time, part of the applied energy is consumed as thermal energy due to frictional resistance based on the rotation of the dipole, and the temperature of the substrate 10 and the like is increased, resulting in a large energy loss. In addition, an eddy current is generated in the substrate 10 and the conductor due to the magnetic field, resulting in energy loss due to eddy current loss.

However, according to the present embodiment, even when high-frequency alternating currents I ₁ and I ₂ are passed through the first winding 141 and the second winding 241, the current I ₁ causes the first winding 141 to pass through the first winding 141 and the second winding 241. it can always be offset by a magnetic field excited in the second winding 241 a magnetic field excited by the current I _2. Therefore, the movement of the dipole accompanying the fluctuation of the magnetic field can be suppressed, and a part of the energy applied to the first winding 141 and the second winding 241 can be prevented from being consumed as thermal energy in the substrate 10 or the like. . Similarly, the generation of eddy current loss can be prevented. Therefore, the energy loss of the inductor element 40 can be suppressed.

(Relocation wiring, etc.)
As shown in FIG. 1A and FIG. 1B, the electronic substrate 1 according to the present embodiment includes a connection terminal 63 used for connection with a counterpart member, and stress between the substrate 10 and the counterpart member. And a stress relaxation layer 30 for relaxing the difference. Further, the periphery of the substrate 10 is covered with a heat radiating member 72 having a high thermal conductivity.

  A plurality of electrodes 62 are arranged along the periphery of the electronic substrate 1. Due to the recent miniaturization of the electronic substrate 1, the pitch between the adjacent electrodes 62 has become very narrow. When the electronic substrate 1 is mounted on the mating member, there is a possibility that a short circuit occurs between the adjacent electrodes 62. Therefore, in order to widen the pitch between the electrodes 62, a rearrangement wiring 64 for the electrodes 62 is formed.

  Specifically, a plurality of pads constituting the connection terminal 63 are formed at the center of the surface of the electronic substrate 1. A rearrangement wiring 64 drawn from the electrode 62 is connected to the connection terminal 63. As a result, the narrow-pitch electrodes 62 are drawn out to the central portion to widen the pitch. For the formation of such an electronic substrate 1, W-CSP (Wafer Level Chip Scale Package) technology in which rearrangement wiring, resin sealing, and the like are collectively performed in a wafer state and then separated into individual electronic substrates 1. Is being used.

Bumps 78 are formed on the surface of the connection terminal 63. The bumps 78 are, for example, solder bumps, and are formed by a printing method or the like. The bump 78 is mounted on the connection terminal of the counterpart member.
A solder resist 66 is formed around the bump 78. The solder resist 66 serves as a partition wall of the bump 78 when the bump 78 is mounted on the counterpart member, and is made of an electrically insulating material such as a resin. The solder resist 66 covers the entire surface of the substrate 10 including the inductor element.

  By the way, when the electronic substrate 1 is mounted on the counterpart member, a thermal stress is generated between the two due to the difference in thermal expansion coefficient between the substrate 10 of the electronic substrate 1 and the counterpart member. In order to relieve the thermal stress, the stress relaxation layer 30 is formed between the connection terminal 63 and the substrate 10. The stress relaxation layer 30 is formed to a predetermined thickness from a resin material such as photosensitive polyimide, BCB (benzocyclobutene), or phenol novolac resin.

  In the electronic substrate 1 of the present embodiment, the stress relaxation layer 30 is formed in a region other than the region where the inductor element 40 is formed. If an inductor element is formed on the surface of the stress relaxation layer 30, it is possible to secure a distance between the inductor element 40 and the substrate 10 made of silicon or the like, and suppress leakage current generated by interference of magnetic flux with silicon. can do. As a result, the Q value of the inductor element can be improved, and the electrical characteristics of the inductor element 40 can be improved.

  Returning to FIG. 1B, the heat radiating member 72 is disposed so as to cover the back surface and the side surface of the substrate 10. The heat radiating member 72 is made of a material having higher thermal conductivity than the constituent material of the substrate 10. For example, the heat radiating member 72 can be formed by press-molding a Cu thin plate having a thermal conductivity higher than that of silicon constituting the substrate 10.

  The heat dissipation member 72 is fixed to the substrate 10 via an adhesive 71 disposed on the back surface of the substrate 10. As the adhesive 71, it is desirable to employ a resin paste that is a main component in which metal fine particles having high thermal conductivity are dispersed. Specifically, it is possible to employ an Ag paste in which Ag fine particles are dispersed. The adhesive 71 can be applied by discharging it from a dispenser or the like.

  As described above, when the electronic substrate 1 of this embodiment is used in a power supply circuit, a large current flows through the inductor element 40 and the electronic substrate 1 generates heat. In the present embodiment, the periphery of the electronic substrate 1 is covered with the heat radiating member 72 and the heat radiating member 72 is fixed to the substrate 10 with an adhesive having a high thermal conductivity. It becomes possible to do. Thereby, the temperature rise of the electronic substrate 1 can be suppressed, and the reliability of the electronic substrate can be improved. As a result, the electronic substrate of this embodiment can be used for the power supply circuit.

(Mounting structure)
FIG. 5 is an explanatory diagram of the mounting structure of the electronic substrate according to the first embodiment, and is a cross-sectional view of a portion corresponding to the line BB in FIG. As shown in FIG. 5, the electronic substrate 1 according to this embodiment is used by being mounted on a counterpart member 90. A wiring pattern (not shown) and lands 92 and 94 are formed on the surface of the mating member 90. Solder balls 93 and 95 are formed on the surfaces of the lands 92 and 94. In this embodiment, the solder bonding method has been described. However, instead of the solder balls 93 and 95, other known mounting methods such as an adhesive bonding method such as silver paste may be used.

  Then, by connecting the solder bump 78 of the electronic substrate 1 and the solder ball 93 of the counterpart member 90, the connection terminal 63 of the electronic substrate 1 and the land 92 of the counterpart member 90 are electrically connected. Further, the heat radiating member 72 of the electronic substrate 1 is connected to the land 94 of the mating member 90 via the solder ball 95. These connections can be performed collectively using reflow, FCB (Flip Chip Bonding), or the like.

  Thus, by connecting the heat dissipation member 72 to the counterpart member 90, the heat dissipation efficiency of the electronic substrate 1 can be improved. Further, the heat radiating member 72 can be grounded via the mating member 90, and the electronic substrate 1 can be electrically isolated from the outside. As a result, the reliability of the electronic substrate can be improved.

(Second Embodiment)
FIG. 6 is a plan view of the electronic substrate according to the second embodiment. In FIG. 6, the upper side of the drawing is the + Y direction, and the right side of the drawing is the + X direction. In the electronic substrate according to the second embodiment, the first winding 141, the second winding 241 and the third winding 341 are formed around the second magnetic layer 31, and the first winding 141 and the second winding 241 are formed. The third winding 341 is connected to different first electrode pairs 111 and 121, second electrode pairs 211 and 221 and third electrode pairs 311 and 321, respectively. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

In the second embodiment, the first magnetic layer 43a is formed in a planar shape in the formation region of the inductor element 40 on the surface of the substrate 10, and the plurality of first wirings 12 are formed substantially in parallel on the surface. A gap between adjacent first wirings 12 is filled with a nonmagnetic material 44 to form a first nonmagnetic layer 44a. Furthermore, the linear 2nd magnetic layer 31 is formed so that the center part of the some 1st wiring 12 and a 1st nonmagnetic layer may be covered. Further, a plurality of second wirings 22 are formed substantially in parallel so as to cross the surface of the second magnetic layer 31. A gap between adjacent second wirings is filled with a nonmagnetic material 44 to form a second nonmagnetic layer 44b. Further, a third magnetic layer 43b is formed so as to cover the second wiring 22 and the second nonmagnetic layer 44b.
The third magnetic layer 43b is formed so as to overlap with the peripheral edge of the first magnetic layer 43a. The third magnetic layer 43 b is formed so as to overlap both end portions of the second magnetic layer 31. Thereby, the periphery of the inductor element 40 is covered with the magnetic material 43, and a closed magnetic circuit is formed in the inductor element 40.

Here, the + X side end of one first wiring 113 and the −X side end of another first wiring 114 not adjacent to the first wiring 113 are sequentially connected by the second wiring 122. Thus, the first winding 141 is formed. In addition, an end on the + X side of one first wiring 213 adjacent to one first wiring 113 and an end on the −X side of another first wiring 214 not adjacent to the first first wiring 213 are provided. The second winding 241 is formed by being sequentially connected by the second wiring 222. Further, an end on the + X side of one first wiring 313 adjacent to one first wiring 213 and an end on the −X side of another first wiring 314 not adjacent to the first first wiring 313 are provided. The third winding 341 is formed by being sequentially connected by the second wiring 322. As a result, three first windings 141, second windings 241, and third windings 341 are formed around the second magnetic layer 31.
Similarly, the first nonmagnetic layer 44a and the second nonmagnetic layer 44b are connected in a winding shape, and a nonmagnetic material is formed in the gap between the adjacent first winding 141, second winding 241 and third winding 341. 44 is filled.

  Of the plurality of first wirings 12, three first wirings 113, 213, and 313 arranged at the end on the + Y side are connected to different electrodes 111, 211, and 311 through the connection wiring 11a. Yes. In addition, among the plurality of second wirings 22, three second wirings 128, 228, and 328 arranged at the end portion on the −Y side are coupled to different electrodes 121, 221, and 321 through the coupling wiring 21 a. ing. As a result, the three first windings 141, the second winding 241, and the third winding 341 are different from each other in the first electrode pair 111 and 121, the second electrode pair 211 and 221, and the third electrode pair 311 and 321, respectively. It is connected to.

  As described above, in the electronic substrate according to the second embodiment, a plurality of first windings 141, second windings 241, and third windings 341 are formed around the second magnetic layer 31. The first electrode pair 111 and 121, the second electrode pair 211 and 221, and the third electrode pair 311 and 321 are connected to each other. Thus, by making the winding of the inductor element into a braided structure, it is possible to increase the winding density of the winding and improve the magnetic flux density. As a result, the L value (inductance elementance) and Q value of the inductor element 40 can be remarkably improved, and the electrical characteristics of the electronic substrate can be improved.

Here, as in the first embodiment, in the inductor element 40, a power source (not shown) connected to the first electrode pair 111, 121, a power source (not shown) connected to the second electrode pair 211, 221 and the first The power sources (not shown) connected to the three electrode pairs 311 and 321 are different. That is, the current _{I 1} from the first electrode pair 111, 121 of the electrode 111 to the electrode 121, also the current _{I 2} from the electrode 221 of the second electrode pair 211 and 221 to the electrode 211, also of the third electrode pair 311, 321 The current I ₃ can be supplied from the electrode 311 to the electrode 321.

Thereby, the electrode 111, the electrode 311, and the electrode 221 can be made into a positive pole, and the electrode 211, the electrode 121, and the electrode 321 can be made into a negative pole at a certain time. In this case, the direction of flow of current I ₁ supplied to the first winding 141, and the flow direction of the current I ₂ is supplied to the second winding 241 adjacent have opposite directions to each other. Similarly, the direction of flow of current I ₂ is supplied to the second winding 241, the current flow direction I ₃ is supplied to the third winding 341 to adjacent the opposite directions to each other. In this way, the polarities of the windings are made different so that different currents I ₁ , I ₂ , and I ₃ flow alternately through the adjacent first winding 141, second winding 241, and third winding 341. Supply.
With this configuration, for example, the magnetic field excited in the first winding 141 and the third winding 341 by the currents I ₁ and I ₃ and the reverse direction excited in the second winding 241 by the current I ₂ Can be canceled by the magnetic field.

At this time, as shown in FIG. 7, the currents I ₁ and I _{2 are} alternating currents having the same frequency as the first winding 141, the second winding 241, and the third winding 341 and different phases θ by 120 °. , it may be supplied to I _3. Thereby, even if the positive electrode and the negative electrode are periodically switched in the first electrode pair 111, 121, the second electrode pair 211, 221 and the third electrode pair 311, 321, the first winding 141, the second winding The direction in which the current supplied to one of the windings 241 and 341 flows can be always opposite to the direction in which the current supplied to the other two windings flows.

For example, in FIG. 7, when the phase of the current I ₁ is 30 °, the electrode 111, the electrode 311 and the electrode 221 are positive, and the electrode 211, the electrode 121 and the electrode 321 are negative as shown in FIG. A positive current I ₁ is supplied from the electrode 111 to the electrode 121, a negative current I ₂ is supplied from the electrode 221 to the electrode 211, and a positive current I ₃ is supplied from the electrode 311 to the electrode 321.
Therefore, even if the currents I ₁ , I ₂ , and I ₃ are high-frequency alternating currents, the magnetic fields excited in the first winding 141 and the third winding 341 by the currents I ₁ and I ₃ are caused by the current I ₂ . It can be canceled by the magnetic field excited by the second winding 241. Further, as shown in FIG. 7, it can be understood that the magnetic field excited in one winding can be canceled out by the magnetic field excited in the other two windings at other times as well.

Therefore, according to the present embodiment, even when high-frequency alternating currents I ₁ , I ₂ , and I ₃ are passed through the first winding 141, the second winding 241, and the third winding 341, Since the magnetic field excited by the other winding can be canceled by the magnetic field excited by the other two windings, the first winding 141, the second winding 241 and the first winding 241 can be canceled as in the first embodiment. A part of the energy applied to the three windings 341 can be prevented from being consumed as thermal energy in the substrate 10 or the like. Further, it is possible to prevent eddy current loss from occurring in the substrate 10 and the conductor. Therefore, the energy loss of the inductor element 40 can be suppressed.

In the second embodiment, the spiral winding is arranged around the linear core 42 to form the linear inductor element 40. However, it is possible to form inductor elements having other shapes. is there.
FIG. 8 is a plan view of a modification of the inductor element. In FIG. 8, description of windings and the like is omitted, and only a schematic shape of the inductor element is shown. As shown in FIG. 8A, if a substantially circular toroidal inductor element is formed, the magnetic flux forms a closed loop, and thus a highly efficient inductor element can be provided. Further, if the substantially rectangular shape shown in FIG. 8B or the polygonal shape shown in FIG. 8C is used, the design is easy and an inductor element having desired characteristics can be formed.

  Moreover, you may form the spiral inductor element shown in FIG.8 (d). According to this structure, it becomes possible to arrange many windings in a narrow region, and the magnetic flux density can be improved. It should be noted that the magnetic flux density can be further improved by providing a space in the center of the spiral. Further, as shown in FIG. 8E, a spiral inductor element that gradually increases from the inside toward the outside may be formed. At this time, it is desirable to increase the cross-sectional areas of the first wiring and the second wiring from the inside toward the outside. According to this configuration, it is possible to achieve both the reduction of the wiring resistance of the inductor element and the reduction of the formation region, and a highly efficient inductor element can be formed.

(Electronics)
Next, a method for using the electronic substrate described above and an example of an electronic device including the electronic substrate described above will be described.
FIG. 9 is a perspective view of the mobile phone. The electronic board described above is arranged inside the casing of the mobile phone 300. In this way, by using the electronic substrate in a state where the energy loss of the inductor element having a plurality of windings is minimized, a low-cost electronic substrate with excellent electrical characteristics and low energy loss can be used as a mobile phone. It can be provided in such electronic equipment. Therefore, a low-cost mobile phone with excellent electrical characteristics and energy efficiency can be provided.

  Note that the semiconductor device described above can be applied to various electronic devices other than mobile phones. For example, LCD projectors, multimedia personal computers (PCs) and engineering workstations (EWS), pagers, word processors, TVs, viewfinder type or monitor direct view type video tape recorders, electronic notebooks, electronic desk calculators, car navigation systems The present invention can be applied to electronic devices such as a device, a POS terminal, and a device provided with a touch panel. In either case, a low-cost electronic device having excellent electrical characteristics can be provided.

It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. In other words, the specific materials and layer configurations described in the embodiments are merely examples, and can be changed as appropriate.
For example, when different currents are alternately passed through adjacent windings, the polarity of the current is set to each winding so that the sum of the current values flowing through the windings is smaller than the sum of the absolute values of the current values. You may supply in the state made different. With this configuration, the magnetic field excited in the winding by the forward current can be canceled out by the reverse magnetic field excited in the other winding by the reverse current.

  In the above embodiment, the inductor element is formed on the surface of the electronic substrate. However, the inductor element may be formed on the back surface of the electronic substrate, and the conduction with the surface may be ensured by the through electrode. Moreover, in the said embodiment, although the inductor element was formed in the electronic substrate in which the electronic circuit was formed, you may form an inductor element in the electronic substrate which consists of an electrically insulating material. Moreover, in the said embodiment, although the 1st wiring and the 2nd wiring were formed by the electrolytic plating method, you may employ | adopt other film-forming methods, such as a sputtering method and a vapor deposition method.

  In the example described above, the mixed structure of the relocation wiring type wafer level package structure and the inductor structure has been described. However, the wafer level package structure is not limited to this, and a wafer having a Cu post structure in the external terminal portion. Other known wafer level package structures such as a level package structure and an inductor structure may be mixed. In either case, a structure excellent in both reliability and inductor characteristics can be provided.

It is explanatory drawing of the electronic substrate which concerns on 1st Embodiment. It is explanatory drawing of an inductor element. It is side surface sectional drawing in the DD line of Fig.2 (a). It is explanatory drawing of the modification of an electronic substrate. It is explanatory drawing of the mounting structure of the electronic substrate which concerns on 1st Embodiment. It is explanatory drawing of the inductor element which concerns on 2nd Embodiment. It is a graph of the electric current value of the inductor element which concerns on 2nd Embodiment. It is explanatory drawing of the modification of an inductor element. It is a perspective view of a mobile phone.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic substrate 10 ... Board | substrate 12 ... 1st wiring 22 ... 2nd wiring 31 ... 2nd magnetic layer (insulating layer) 40 ... Inductor element 41 ... Winding 43 ... Magnetic body material 44 ... Nonmagnetic material 71 ... Adhesive 72 ... Heat dissipation member 111,121 ... 1st electrode pair (electrode) 211,221 ... 2nd electrode pair (electrode) 311,321 ... 3rd electrode pair (electrode) 113,114,118,213,214,218,313 314 ... 1st wiring 122,128,222,228,322 ... 2nd wiring 141 ... 1st winding (winding) 241 ... 2nd winding (winding) 341 ... 3rd winding (winding) 300 ... Mobile phone (electronic equipment) I ₁ , I ₂ , I ₃ ... current

Claims (9)

An electronic board having an inductor element on a board,
A plurality of first wirings formed on the substrate;
An insulating layer continuously formed so as to cover a central portion of the plurality of first wirings;
A plurality of second wirings formed to cross the surface of the insulating layer,
The second wiring is disposed so as to sequentially connect an end portion of the one first wiring and an end portion of the other first wiring that is not adjacent to the first first wiring,
The inductor element includes a plurality of windings including the first wiring and the second wiring,
The plurality of windings are connected to different electrodes, respectively;
An electronic substrate, wherein different signals alternately flow in adjacent windings.   The electronic substrate according to claim 1, wherein the insulating layer is a magnetic layer having at least a surface insulated. The inductor element includes two windings;
3. The electronic substrate according to claim 1, wherein an alternating current having the same frequency is supplied from each electrode to each of the windings with a phase different by 180 degrees. The inductor element includes three windings,
3. The electronic substrate according to claim 1, wherein an alternating current having the same frequency is supplied from each electrode to each of the windings with a phase different by 120 degrees.   The gap between the adjacent windings is filled with a nonmagnetic material, and the periphery of the inductor element is covered with a magnetic material. The electronic substrate as described.   6. The electron according to claim 1, wherein the whole or a part of the periphery of the substrate is covered with a heat dissipation member made of a material having a higher thermal conductivity than the substrate. substrate.   The electronic substrate according to claim 6, wherein the heat dissipation member is fixed to the substrate through an adhesive in which metal fine particles are dispersed. A plurality of first wirings formed on the substrate;
An insulating layer continuously formed so as to cover a central portion of the plurality of first wirings;
A plurality of second wirings formed to cross the surface of the insulating layer,
The second wiring is disposed so as to sequentially connect an end portion of the one first wiring and an end portion of the other first wiring that is not adjacent to the first first wiring,
A method of using an electronic substrate comprising an inductor element, comprising a plurality of windings comprising the first wiring and the second wiring, wherein the plurality of windings are connected to different electrodes, respectively.
A method of using an electronic board, wherein different signals alternately flow in adjacent windings.   An electronic apparatus comprising the electronic substrate according to claim 1.

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