JP2011243870A - Coil mounting board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil mounting board in which heat dissipation of a surface-mounted coil is enhanced.SOLUTION: The coil mounting board comprises a wiring board including lands as a conductor pattern, a surface-mounted coil having a body including a core and a coil, and terminals connected electrically with the coil and connected electrically with the lands of the wiring board, and a heat dissipation member arranged on the surface of the wiring board facing the undersurface of the body. An insulating base is formed by laminating a plurality of sheets of resin film so that at least every other sheet is a thermosetting resin film located contiguously to the undersurface of the body of the surface-mounted coil. The wiring board has a land formation surface between the arrangement surface of the heat dissipation member and the surface on the opposite side thereof. The surface-mounted coil is buried in the insulating base not to project from the surface of the wiring board on the opposite side of the heat dissipation member mounting surface, and the undersurface of the body is sealed of the thermosetting resin of the insulating base.

Description

  The present invention relates to a coil mounting board in which a surface mounting type coil is surface mounted on a wiring board.

  Conventionally, as shown in Patent Documents 1 and 2, for example, surface mounting including a main body portion including a core and a coil, and a terminal portion electrically connected to the coil and electrically connected to a land of the wiring board Mold coils are known.

JP 2006-278663 A JP 2001-217127 A

  In a conventional coil mounting board in which the terminal part of the surface mounting coil is soldered to the land of the wiring board, for example, and the surface mounting coil is surface mounted on the wiring board, the surface mounting coil faces the wiring board in the main body part An air layer is formed between the lower surface to be formed and the land forming surface of the wiring board (see FIG. 2 of Patent Document 1 and FIG. 3 of Patent Document 2).

  Since this air layer functions as a heat insulating layer, even if a heat radiating member such as a heat sink or a heat radiating fin is disposed on the back surface of the land forming surface of the wiring board, heat radiation from the surface mount coil to the heat radiating member is not sufficiently performed. There is a problem.

  In view of the above problems, an object of the present invention is to provide a coil mounting board with improved heat dissipation of a surface mount coil.

In order to achieve the above object, the coil mounting board according to claim 1,
An insulating base material comprising: an insulating base material; a conductor pattern disposed on the insulating base material and extending in a direction perpendicular to the thickness direction of the insulating base material; and a conductor filled in a via hole of the insulating base material. A wiring board having an interlayer connection via extending in the thickness direction and including a land as a conductor pattern;
A main body including a core and a coil, and a position electrically connected to the coil and the same as the lower surface facing the land forming surface of the main body in the thickness direction of the insulating base or a position closer to the land forming surface than the lower surface A surface mount coil having a mounting portion disposed on the terminal portion, the terminal portion being electrically connected to a land of the wiring board,
A heat dissipating member that includes a metal material and is disposed on a surface of the wiring board that is one of the surfaces perpendicular to the thickness direction of the insulating base material and faces the lower surface of the main body,
The insulating base material includes a plurality of resin films including the thermoplastic resin film so that the thermoplastic resin films including the thermoplastic resin are adjacent to the lower surface of the main body of the surface mount coil while being positioned at least every other sheet. Layered and integrated,
The wiring board has a land forming surface between the disposition surface of the heat dissipation member and the surface opposite to the disposition surface in the thickness direction of the insulating base,
The surface mount coil is embedded in the insulating base so as not to protrude from the surface opposite to the heat dissipating member placement surface of the wiring board in the thickness direction of the insulating base, and the lower surface of the main body portion is made of the insulating base. It is sealed with a thermoplastic resin.

  Such a coil mounting board is formed by laminating a plurality of resin films so that at least every other thermoplastic resin film is positioned so as to be adjacent to the lower surface of the main body of the surface mount coil and the heat radiating member. It can be formed by a method of pressurizing and heating from above and below in the stacking direction with a press machine. In this method, 1) the terminal portion and the land are electrically connected and the coil is embedded in the wiring board, 2) the wiring board is formed, and 3) the heat radiating member is connected to the wiring board. Can be fixed to. Therefore, the manufacturing process can be simplified.

  In addition, the thermoplastic resin film adjacent to the lower surface of the main body portion of the surface mount coil softens during the pressurization and heating described above, and adheres to the lower surface of the main body portion by flowing under pressure. Thereby, it can suppress that an air layer is formed between the lower surface of a main-body part and the land formation surface of a wiring board. That is, the heat dissipation from the surface mount coil to the heat dissipation member is improved.

  As mentioned above, according to this invention, the coil mounting board | substrate which improved the heat dissipation of the surface mount type coil can be provided.

  As described in claim 2, the first heat transfer path part including the interlayer connection via, disposed in the opposing region of the lower surface of the main body part and the heat dissipation member, one end of which is electrically connected to the heat dissipation member, The wiring board may have a configuration.

  According to this, the heat dissipation from the surface mount coil to the heat dissipation member can be further improved by the first heat transfer path portion.

  According to a third aspect of the present invention, it is preferable that the first heat transfer path portion includes a conductor pattern different from the land arranged on the land forming surface and an interlayer connection via connected to the conductor pattern.

  According to this, the distance between the first heat transfer path portion and the lower surface of the body portion of the surface mount coil can be reduced by the amount of the conductor pattern arranged on the land forming surface. In other words, the thickness of the insulating base material interposed between the first heat transfer path portion and the lower surface of the main body portion can be reduced, or the interposed insulating base material can be eliminated. Thereby, the heat dissipation from the surface mount coil to the heat dissipation member can be further improved.

As described in claim 4, the mounting surface of the terminal portion is disposed closer to the land forming surface than the lower surface of the main body portion,
The first heat transfer path portion includes a plurality of interlayer connection vias, includes an interlayer connection via disposed at the same position as the terminal portion in the thickness direction of the insulating base, and is opposite to the connection end with the heat dissipation member. It is preferable that the end of the interlayer connection via forming the end is in contact with the lower surface of the main body.

  Thus, if the 1st heat-transfer path | route part is made to contact the lower surface of a main-body part, the heat dissipation from a surface mount type coil to a thermal radiation member can further be improved.

  As described in claim 5, in the thickness direction of the insulating base material, a plurality of interlayer connection vias are connected directly or via a conductor pattern, and are disposed to face the side surface of the main body, with one end being a heat radiating member. It is good also as a structure which a wiring board has the 2nd heat-transfer path | route part electrically connected to.

  According to this, the heat dissipation from the surface mount coil to the heat radiating member can be further improved by the second heat transfer path portion disposed opposite to the side surface of the main body portion.

  According to a sixth aspect of the present invention, the second heat transfer path portion may be disposed so as to surround the side surface of the main body portion of the surface mount coil. According to this, the heat dissipation path from the side surface side of the main body can be increased to improve heat dissipation.

  Specifically, as described in claim 7, it is preferable that the plurality of second heat transfer path portions are arranged with a predetermined interval so as to surround the main body side surface of the surface mount coil. According to this, it becomes easy to pull out the conductor pattern (electrical wiring) from the land.

As described in claim 8, the core and the coil of the surface mount coil and the first heat transfer path are electrically separated,
It is good also as a structure provided with the terminal part for electric potential fixation exposed to the exterior from an insulating base material, and fixing a 2nd heat-transfer path | route part to predetermined electric potential (for example, grounding potential).

  According to this, the noise radiated | emitted to space from a surface mount type coil can be shielded by the 2nd heat-transfer path | route part, a thermal radiation member, and a 1st heat-transfer path | route part at least. In the configuration including the third heat transfer path portion described later, radiation noise can be reduced particularly effectively.

As described in claim 9, in the thickness direction of the insulating base material, the second heat transfer path portion has an end portion on the opposite side to the connection end with the heat dissipation member, and an upper surface opposite to the lower surface in the main body portion. Is farther away from the heat dissipation member,
A conductor pattern as a third heat transfer path part, which is disposed opposite to the upper surface of the main body part and is electrically connected to the end of the second heat transfer path part opposite to the connection end of the heat dissipation member, The wiring board may have a configuration.

  According to this, the heat dissipation from the surface mount coil to the heat radiating member can be further improved by the third heat transfer path portion disposed opposite to the upper surface of the main body portion.

  Since the operational effects of the inventions according to claims 10 to 14 are the same as the operational effects of the inventions according to claims 5 to 9, respectively, description thereof is omitted.

According to the fifteenth aspect of the present invention, a plurality of insulating base materials are provided so that the thermoplastic resin film is adjacent to the lower surface of the body portion of the surface mount coil, the upper surface opposite to the lower surface, and the heat dissipation member. The resin film is laminated and integrated,
The entire surface mount coil is preferably sealed with a thermoplastic resin of an insulating substrate.

  According to this, since the surface mount coil is sealed by the thermoplastic resin film adjacent to the surface mount coil at least in the thickness direction, the reliability of the surface mount coil (for example, the connection reliability between the terminal portion and the land) Property) can be improved. In addition, since the formation of the wiring board, the surface mounting of the surface mount coil, and the sealing of the surface mount coil can be performed in a lump, the manufacturing process can be simplified.

In addition, as described in claim 16, the wiring board has a recess that opens on a surface opposite to the surface on which the heat dissipating member is disposed,
The surface mount type coil is disposed in the recess, and the upper surface opposite to the lower surface in the main body is in the same position as the surface opposite to the heat dissipating member arrangement surface in the wiring board in the thickness direction of the insulating substrate. The gap between the side wall of the recess and the side surface of the surface mount coil may be filled with a potting material having electrical insulation and higher thermal conductivity than the insulating base material.

  According to this, compared with the structure by which the side surface of the main-body part was sealed with the thermoplastic resin, the heat dissipation from the main-body-part side surface side can be improved. In addition, the coil mounting board | substrate of the said structure can be obtained by pressurizing both a surface mounting type coil and a wiring board with the flat hot press board of a vacuum hot press machine.

It is sectional drawing which shows schematic structure of the coil mounting board | substrate which concerns on 1st Embodiment. It is sectional drawing which shows the preparatory process of a resin film among the manufacturing processes of the coil mounting board | substrate shown in FIG. It is a top view which shows schematic structure of the thermoplastic resin film adjacent to the lower surface of the main-body part of a surface mount type coil. It is sectional drawing which shows a lamination process among the manufacturing processes of the coil mounting board | substrate shown in FIG. It is sectional drawing which shows the modification of the method of manufacturing the coil mounting board | substrate shown in FIG. It is sectional drawing which shows the modification of the coil mounting board | substrate which concerns on 1st Embodiment. It is sectional drawing which shows schematic structure of the coil mounting board | substrate which concerns on 2nd Embodiment. It is sectional drawing which shows schematic structure of the coil mounting board | substrate which concerns on 3rd Embodiment. It is sectional drawing which shows schematic structure of the coil mounting board | substrate which concerns on 4th Embodiment. It is sectional drawing which shows schematic structure of the coil mounting board | substrate which concerns on 5th Embodiment. It is a top view which shows arrangement | positioning of a 2nd heat-transfer path | route part. It is a top view which shows the modification of arrangement | positioning of a 2nd heat-transfer path | route part. It is sectional drawing which shows schematic structure of the coil mounting board | substrate which concerns on 6th Embodiment. It is sectional drawing which shows schematic structure of the coil mounting board | substrate which concerns on 7th Embodiment. It is sectional drawing which shows schematic structure of the coil mounting board | substrate which concerns on 8th Embodiment. It is sectional drawing which shows the state before a potting process among the manufacturing processes of the coil mounting board | substrate shown in FIG.

  The present invention is mainly characterized in the configuration of a coil mounting substrate formed using a batch lamination method known as PALAP. Therefore, as the basic configuration and manufacturing method of the wiring board constituting the coil mounting board, the configuration related to PALAP that has been filed by the present applicant can be adopted as appropriate unless otherwise specified. PALAP is a registered trademark of Denso Corporation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, common or related elements are given the same reference numerals.

(First embodiment)
Hereinafter, the thickness direction of the insulating substrate (in other words, the lamination direction of the plurality of resin films) is simply referred to as the thickness direction, and the direction perpendicular to the thickness direction is simply referred to as the vertical direction. Further, unless otherwise specified, the thickness means a thickness along the thickness direction.

  A coil mounting board 10 (also referred to as an electronic device) shown in FIG. 1 is embedded in a wiring board 30 and an insulating base material 31 constituting the wiring board 30, and a surface mounting type coil 50 mounted on the wiring board 30. And a heat radiating member 70 for radiating the heat of the surface mount coil 50 to the outside.

  The wiring board 30 includes an insulating base 31, a conductor pattern disposed on the insulating base 31 and extending in the vertical direction, and a conductor filled in a via hole of the insulating base, and extending in the thickness direction. Has connecting vias.

  The insulating base material 31 is made of an electrically insulating material, and has a function as a base material for holding the constituent elements other than the base material 31, conductor pattern, interlayer connection via, surface mount coil 50, and heat dissipation member 70 in a predetermined position. Fulfill. In the present embodiment, the surface mount type coil 50 is further held and protected in its interior.

  The insulating substrate 31 mainly includes a resin and at least a thermoplastic resin as the resin. A plurality of resin films including a thermoplastic resin film are laminated, and are bonded and integrated by pressing and heating. Being done. The reason for including a thermoplastic resin is to use a thermoplastic resin that withstands high temperatures and softens as an adhesive and a sealing material when forming an insulating substrate in a lump in the pressurization / heating process described below. .

  For this reason, the plurality of resin films may include a thermoplastic resin film so as to be positioned at least every other sheet in a laminated state. For example, it is good also as a structure containing only a thermoplastic resin film, and good also as a structure containing a thermosetting resin film with a thermoplastic resin film. Furthermore, in this embodiment, in order to seal the entire surface mount coil 50 and to integrate the heat dissipation member 70, a lower surface 51a, an upper surface 51b, and a heat dissipation member of a main body 51 of the surface mount coil 50 described later. A thermoplastic resin film is included so as to be adjacent to 70.

  As the thermoplastic resin film, at least one of a film containing an inorganic material such as glass fiber and aramid fiber and a film made of a thermoplastic resin not containing an inorganic material can be employed together with the thermoplastic resin. Similarly, as the thermosetting resin film, at least one of a film containing the inorganic material and a film made of a thermosetting resin not containing the inorganic material can be employed together with the thermosetting resin.

  As shown in FIG. 1, the insulating base material 31 according to the present embodiment includes a thermoplastic resin film 32 a, a thermosetting resin film 33 a, and a thermoplastic resin from the heat dissipating member arrangement surface 30 a side of the wiring board 30 in the thickness direction. The film 32b, the thermosetting resin film 33b, the thermoplastic resin film 32c, the thermosetting resin film 33c, the thermoplastic resin film 32d, the thermosetting resin film 33d, the thermoplastic resin film 32e, and the thermosetting resin film 33e in this order. A total of 10 resin films are laminated. That is, the insulating base material 31 is configured by alternately laminating thermoplastic resin films and thermosetting resin films.

  Further, as the thermoplastic resin films 32a to 32e, resin films composed of 30% by weight of polyetheretherketone (PEEK) and 70% by weight of polyetherimide (PEI) are employed. On the other hand, films made of thermosetting polyimide (PI) are employed as the thermosetting resin films 33a to 33d.

  Among the resin films described above, the thermoplastic resin film 32 b corresponds to a thermoplastic resin film adjacent to the lower surface 51 a of the main body portion of the surface mount coil 50, and the thermoplastic resin film 32 e is the main body of the surface mount coil 50. It corresponds to a thermoplastic resin film adjacent to the upper surface 51b of the part.

  The conductive pattern is formed by patterning a conductive foil, and the interlayer connection via is a resin film in which a conductive paste is filled in via holes (through holes) provided along the thickness direction. The conductive particles are sintered by pressing and heating. These conductor patterns and interlayer connection vias constitute an electrical wiring portion. In addition to the electrical wiring portion, a heat dissipation wiring portion for radiating heat generated by the operation of the electronic component mounted on the wiring board 30 to the outside can be configured.

  In this embodiment, the conductor pattern is formed by patterning a copper (Cu) foil, and the interlayer connection via is made of an Ag—Sn alloy. A circuit is configured on the wiring board 30 by the electronic parts including the surface-mounting coil 50 mounted on the wiring board 30 and the wiring portion including the conductor pattern and the interlayer connection via. At the interface between the conductor pattern made of Cu and the interlayer connection via made of Ag—Sn alloy, a metal diffusion layer (Cu—Sn alloy layer) formed by mutual diffusion of Cu and Sn is formed. Connection reliability between the pattern and the interlayer connection via is improved.

  In FIG. 1, only the surface-mounted coil 50 is shown as an electronic component, and only the land 34 is shown as a wiring portion. The land 34 is an electrode portion of the conductor pattern to which the terminal portion 52 of the surface mount coil 50 is electrically and mechanically connected. Two lands 34 correspond to the terminal portion 52 of the surface mount coil 50. 34 are provided apart from each other. Each land 34 is electrically and mechanically connected to a corresponding terminal portion 52 of the surface mount coil 50 by solder, Ag paste, or the like (not shown).

  In addition, as shown in FIG. 1, three interlayer connection vias 36 respectively formed in the thermoplastic resin film 32a, the thermosetting resin film 33a, and the thermoplastic resin film 32b are directly connected to form a first heat radiation wiring portion. A heat transfer path portion 35 is configured.

  The surface mount type coil 50 is electrically connected to the main body 51 including the core and the coil, and at the same position as the lower surface 51a of the main body 51 facing the land forming surface of the wiring board 30 in the thickness direction. And a terminal portion 52 having a mounting surface disposed closer to the land forming surface than the lower surface 51a. This terminal portion 52 corresponds to an electrode of the surface mount coil 50. Further, the entire surface mount coil 50 is sealed with the insulating base 31 described above.

  In this embodiment, a coil is formed by winding a coated copper wire coated with an electrically insulating material, and a substantially rectangular parallelepiped core made of iron-based dust is provided so as to enclose the coil, and the main body 51 Is configured. That is, the core forms an outer shell of the main body 51.

  Further, terminal portions 52 connected to the coil are led out from a pair of side surfaces 51c of the main body portion 51 facing each other. Each terminal portion 52 is bent along the side surface 51c, further bent at the lower end of the side surface, and arranged along the lower surface 51a of the main body portion 51 within a range not contacting each other. Of the terminal portion 52, a portion disposed along the lower surface 51 a of the main body 51 is disposed at a position closer to the land forming surface than the lower surface 51 a of the main body 51 as a surface facing the land forming surface of the wiring board 30. The surface mounting portion 52a has the mounted surface.

  In the terminal portion 52, the coating on the surface opposite to the surface facing the main body 51 in the surface mounting portion 52 a is mainly removed, and the land 34 can be electrically and mechanically connected. The terminal portion 52 is obtained by applying solder plating to phosphor bronze, and in this embodiment, the solder plating functions as a connecting member that electrically and mechanically connects the terminal portion 52 and the land 34. .

  One end of an interlayer connection via 36 formed in the thermoplastic resin film 32b is connected to the lower surface 51a of the main body 51. That is, one end of the first heat transfer path portion 35 is connected.

  Further, the entire surface mount type coil 50 is sealed with a thermoplastic resin constituting the insulating base 31. Specifically, of the lower surface 51 a of the main body 51, the exposed portion excluding the arrangement portion of the surface mounting portion 52 a of the terminal portion 52 and the connection portion of the interlayer connection via 36, the entire upper surface 51 b of the main body 51, and the main body 51. Among the side surfaces 51c, the thermoplastic resin is in close contact with the exposed portions excluding the portion where the terminal portion 52 is disposed.

  In the present embodiment, as shown in FIG. 1, the thermoplastic resin of the thermoplastic resin film 32b is in close contact with the lower surface 51a of the main body 51, and the heat of the thermoplastic resin film 32e is applied to the upper surface 51b of the main body 51. The plastic resin is in close contact. Further, the thermoplastic resin of the thermoplastic resin films 32b, 32c, 32d, and 32e is in close contact with the side surface 51c of the main body 51.

  Moreover, the terminal part 52, the land 34 of the wiring board 30, and these connection parts are sealed with the thermoplastic resin of the thermoplastic resin films 32b and 32c.

  The heat radiating member 70 is made of a metal material such as Cu, and radiates heat generated by the operation of the electronic component including the surface mount coil 50 mounted on the wiring board 30 to the outside. As such a heat radiating member 70, what is called a heat sink, a heat radiating fin, etc. are employable. Further, the heat radiating member 70 is disposed on the surface 30 a facing the lower surface 51 a of the main body 51 of the surface mount coil 50 among the surfaces 30 a and 30 b of the wiring board 30.

  In the present embodiment, a flat plate-like heat radiating member 70 made of Cu and having a size and shape substantially coincident with the one surface 30a of the wiring board 30 is employed. The heat radiating member 70 is fixed to the wiring board 30 by the thermoplastic resin film 32 a being in close contact with the heat radiating member 70.

  In addition, one end of an interlayer connection via 36 formed in the thermoplastic resin film 32a is connected to the heat dissipation member 70. That is, one end of the first heat transfer path portion 35 is connected. In this embodiment, a metal diffusion layer (C-Sn alloy layer) formed by mutual diffusion of Cu and Sn is formed at the interface between the heat dissipation member 70 made of Cu and the interlayer connection via 36 made of Ag-Sn alloy. As a result, the connection reliability between the interlayer connection via 36 (first heat transfer path portion 35) and the heat dissipation member 70 is improved.

  As described above, in the present embodiment, the heat generated in the surface mount coil 50 is transmitted to the heat radiating member 70 through the first heat transfer path portion 35 formed by directly connecting the three interlayer connection vias 36. Yes. For this reason, the heat dissipation is improved.

  Next, a method for manufacturing the above-described coil mounting substrate 10 will be described.

  First, in order to form the coil mounting substrate 10, a plurality of resin films are prepared. In the present embodiment, as described above, resin films composed of 30% by weight of polyetheretherketone (PEEK) and 70% by weight of polyetherimide (PEI) are employed as the thermoplastic resin films 32a to 32e. Moreover, the film which consists of thermosetting polyimide (PI) is employ | adopted as the thermosetting resin films 33a-33e. Moreover, as an example, all the resin films 32a to 32e and 33a to 33e have the same thickness (for example, 50 μm).

  In this preparatory step, as is well known by the batch lamination method known as PALAP, before the batch lamination, a conductor pattern is formed on the resin film constituting the insulating base material 31, or interlayer connection vias are formed by sintering. The via paste is filled with a conductive paste. The arrangement of the conductor pattern and the via hole filled with the conductive paste is appropriately determined according to the wiring portion and the heat dissipation wiring portion (first heat transfer path portion 35 in the present embodiment).

  The conductor pattern can be formed by patterning a conductor foil adhered to the surface of the resin film. The plurality of resin films constituting the insulating substrate 31 may include a resin film having a conductor pattern. For example, all the resin films have a conductor pattern, or some resin films have a conductor pattern. None of the configurations can be employed. Moreover, as a resin film which has a conductor pattern, both the resin film which has a conductor pattern only on one side, and the resin film which has a conductor pattern on both surfaces in a lamination direction are employable.

  On the other hand, the conductive paste can be obtained by adding ethyl cellulose resin, acrylic resin or the like to the conductive particles for imparting shape retention and kneading in an organic solvent such as terpineol. Then, via holes penetrating the resin film are formed by a carbon dioxide laser or the like, and the conductive paste is filled into the via holes by screen printing or the like. The via hole may be formed with the conductor pattern as a bottom surface, or may be formed at a position where there is no conductor pattern.

  When the via hole is formed on the conductor pattern, the conductive pattern becomes the bottom, so that the conductive paste can be retained in the via hole. On the other hand, when a via hole is formed at a position different from the formation position of the conductor pattern while having a conductor film, or a resin film having no conductor pattern, the conductive paste is fastened in the via hole having no bottom. Therefore, the conductive paste described in Japanese Patent Application No. 2008-296074 by the present applicant is used. As an apparatus (method) for filling the conductive paste, an apparatus (method) described in Japanese Patent Application No. 2009-75034 by the present applicant may be employed.

  This conductive paste decomposes or volatilizes at a temperature lower than the sintering temperature of the conductive particles, becomes molten at a temperature lower than the temperature and higher than room temperature, and is solid at room temperature. A low melting point room temperature solid resin is added. An example of the low melting point room temperature solid resin is paraffin. According to this, by heating at the time of filling, the low melting point room temperature solid resin melts into a paste, and in the cooling after filling, the low melting point room temperature solid resin solidifies, and the conductive paste also solidifies, and the via hole Can be held in. When filling, one end of the via hole may be closed with a flat member.

  In the present embodiment, a film having a copper foil (for example, 18 μm in thickness) attached to one side is prepared as a film for forming a conductor pattern among the ten resin films 32a to 32e and 33a to 33e. A conductor pattern is formed by patterning. In the present embodiment, as an example, the conductor pattern is formed only in the thermosetting resin films 33a to 33e. In the cross section of FIG. 2, only the land 34 of the thermosetting resin film 33a is shown as the conductor pattern. Thus, the thermosetting resin films 33a to 33e are configured to have a conductor pattern on one side, and the thermoplastic resin films 32a to 32e are configured to have no conductor pattern.

  In addition, via holes (not shown) are formed in the films forming the interlayer connection vias among the ten resin films 32a to 32e and 33a to 33e, and a conductive paste is filled in the via holes. And after filling, a solvent is volatilized in a drying process. In the cross section of FIG. 2, only the conductive paste 36 a for the interlayer connection via 36 constituting the first heat transfer path portion 35 is shown as the conductive paste. That is, only the conductive paste 36a of the thermoplastic resin films 32a and 32b and the thermosetting resin film 33a is shown.

  As described above, in the present embodiment, the conductor pattern is formed only on the thermosetting resin films 33a to 33e. Therefore, the thermoplastic resin films 32a to 32e that do not form the conductor pattern have Ag particles and Sn as the conductive particles. A conductive paste containing particles at a predetermined ratio and having a low melting point room temperature solid resin such as paraffin added thereto as described above is used. In addition, for the thermosetting resin films 33a to 33e, the same conductive paste as the thermoplastic resin films 33a to 33e is used to form the interlayer connection via 36.

  Further, in this preparation step, since the laminate has a cavity for accommodating the electronic component such as the surface mount coil 50, a cavity is formed in advance in a part of the plurality of resin films. In the present embodiment, for example, the cavity 37 for accommodating the main body 51 of the surface mount coil 50 is formed in the thermoplastic resin films 32c and 32d and the thermosetting resin films 33b to 33d. For this reason, the said films 32c, 32d, 33b-33d which have the cavity part 37 exhibit rectangular frame shape.

  In addition, a hollow portion 38 for accommodating the terminal portion 52 of the surface mount coil 50 and the land 34 of the wiring board 30 in contact is formed in the thermoplastic resin film 32b. The hollow portion 38 is formed separately by the two terminal portions 52 (lands 34), and a portion facing the lower surface 51a of the main body portion 51 is left in the thermoplastic resin film 32b. For this reason, the thermoplastic resin film 32b which has the two cavity parts 38 exhibits a Japanese character shape as shown in FIG. 2 and 3, a portion of the thermoplastic resin film 32b positioned between the two cavities 38 in one direction in the vertical direction, in other words, a portion separating the two cavities 38. In order to form the interlayer connection via 36 of the first heat transfer path part 35, a via hole filled with the conductive paste 36a is located in a part of the first heat transfer path part 35.

  The cavities 37 and 38 can be formed by mechanical processing such as punching or drilling or laser light irradiation, and are formed with a predetermined margin with respect to the physique of the electronic component such as the surface mount coil 50. The formation timing of the cavities 37, 38 may be before or after the formation of the conductor pattern and the via hole for the conductive paste.

  Next, a stacking process for forming a stacked body is performed. In this step, a plurality of resin films including a resin film having a conductor pattern formed on the surface and a resin film filled with a conductive paste in via holes, and at least every other thermoplastic resin film is positioned. The surface mount coil 50 is laminated so as to be adjacent to the lower surface 51a, the upper surface 51b, and one surface of the heat radiating member 70 of the main body 51.

  In the present embodiment, as shown in FIG. 4, from one end side in the stacking direction, the heat dissipation member 70, the thermoplastic resin film 32a, the thermosetting resin film 33a, the thermoplastic resin film 32b, the thermosetting resin film 33b, The main body 51 of the surface mount coil 50 is the plastic resin film 32c, the thermosetting resin film 33c, the thermoplastic resin film 32d, the thermosetting resin film 33d, the thermoplastic resin film 32e, and the thermosetting resin film 33e. Are disposed in the cavity portion 37 and the plurality of resin films 32a to 32e and 33a to 33e and the surface mount coil are arranged so that the surface mounting portion 52a of the terminal portion 52 contacts the corresponding land 34 through the cavity portion 38. 50 and other electronic components are positioned and laminated. Thus, in this embodiment, it laminates | stacks so that the thermoplastic resin films 32a-32e and the thermosetting resin films 33a-33e may be located alternately. In FIG. 4, for the sake of convenience, the elements constituting the laminated body are illustrated separately.

  In this laminated body, the resin film adjacent to the surface-mounted coil 50 in the thickness direction (the laminated direction of the laminated body) becomes the thermoplastic resin films 32b and 32e. At least these resin films 32b and 32e fulfill the function of sealing the periphery of the surface mount coil 50 in the pressurizing / heating process. In the present embodiment, since the resin film surrounding the surface-mounted coil 50 in the vertical direction includes not only the thermosetting resin films 33b to 33d but also the thermoplastic resin films 33c and 33d, the four thermoplastic resin films 32b are included. ˜32e functions to seal the periphery of the surface mount coil 50.

  The thermoplastic resin films 32b and 32e adjacent to the upper surface 51b and the lower surface 51c of the surface mount coil 50 (electronic component) not only do not contain an inorganic material such as glass fiber or aramid fiber in the thermoplastic resin film. It is preferable to employ a material that does not contain an inorganic filler for adjusting the linear expansion coefficient and the melting point. By carrying out like this, it can suppress that a stress is locally applied to an electronic component in a pressurization and a heating process.

  However, when the thermoplastic resin films 32b and 32e that do not contain an inorganic filler for adjusting the linear expansion coefficient and the melting point are used, the difference between the linear expansion coefficient and the electronic component increases due to the absence of the inorganic filler, and the stress associated therewith. May increase. Therefore, a resin film having a low elastic modulus (for example, 10 GPa or less) may be employed as the thermoplastic resin films 32b and 32e in order to reduce stress.

  The thermoplastic resin films 32b and 32e preferably have a thickness of 5 μm or more. If the thickness is less than 5 μm, the stress of the resin films 32b and 32e is increased in the pressurizing / heating step, and may be peeled off from the surface of the surface mount coil 50 (electronic component).

  Next, a pressurizing / heating step is performed in which the laminate is heated while being pressed from above and below in the stacking direction using a vacuum heat press. In this step, the thermoplastic resin is softened and a plurality of resin films are integrated together, and electronic components such as the surface mount coil 50 are sealed, and the conductive particles in the conductive paste are used as a sintered body. Then, a wiring portion having the sintered body and a conductor pattern is formed.

  In the pressurizing / heating step, the resin film is integrated into the insulating base material 31 and the conductive film in the conductive paste (including the conductive paste 36a) is used as a sintered body. A temperature not lower than the glass transition point and not higher than the melting point of the thermoplastic resin to be formed and a pressure of several MPa are maintained for a predetermined time. In the present embodiment, a press temperature of 280 ° C. to 330 ° C. and a pressure of 4 to 5 MPa are maintained for 5 minutes or longer (for example, 10 minutes).

  First, the connection of the resin film part in the pressurizing / heating step will be described.

  The thermoplastic resin films 32a to 32e arranged every other sheet are softened by the heating. Since the pressure is received at this time, the softened thermoplastic resin films 32a to 32e are in close contact with the adjacent thermosetting resin films 33a to 33e. Thereby, the plurality of resin films 32a to 32e and 33a to 33e are integrated together, and the insulating base 31 is formed. At this time, since the adjacent thermoplastic resin film 32 a is also in close contact with the heat radiating member 70, the heat radiating member 70 is also integrated with the insulating base material 31.

  In addition, the thermoplastic resin films 33 b and 33 e adjacent to the surface mount coil 50 flow under pressure and are in close contact with the lower surface 51 a and the upper surface 51 b of the main body 51 of the surface mount coil 50. Further, the thermoplastic resin films 33b to 33e flow under pressure, and enter the gap between the side surface 51c of the main body 51 of the surface mount coil 50 and the thermosetting resin films 33b to 33d, and fill the gap. At the same time, it is in close contact with the side surface 51c of the surface mount coil 50. Therefore, the surface mount coil 50 is sealed with the thermoplastic resin (thermoplastic resin films 32b to 32e).

  Next, in the pressurizing / heating process, the connection of the terminal portion 52 of the surface-implemented coil 50, the conductor pattern (including the land 34), and the interlayer connection via (including the interlayer connection via 36) will be described.

  By the above heating, Sn (melting point: 232 ° C.) in the conductive paste (including the conductive paste 36a) is melted and diffused to Ag particles in the conductive paste to form an Ag—Sn alloy (melting point: 480 ° C.). To do. Further, since pressure is applied to the conductive paste, an interlayer connection via made of an alloy integrated by sintering is formed.

  As a result, the conductive paste 36a in the via hole formed in each of the thermoplastic resin film 32a, the thermosetting resin film 33a, and the thermoplastic resin film 32b is integrated by sintering, and the three interlayer connection vias 36 are directly connected to each other. 1 heat transfer path part 35 is formed.

  Note that the melted Sn also diffuses with Cu of the adjacent conductor pattern. Thereby, a metal diffusion layer (Cu—Sn alloy layer) is formed at the interface between the interlayer connection via (not shown) and the conductor pattern.

  The melted Sn also interdiffuses with Cu constituting the heat dissipation member 70. As a result, a metal diffusion layer (Cu—Sn alloy layer) is formed at the interface between the interlayer connection via 36 that forms one end of the first heat transfer path portion 35 and the heat dissipation member 70.

  Further, the solder plating of the terminal portion 52 is melted, and the surface mounting portion 52a and the land 34 are mainly electrically and mechanically connected via the solder.

  As described above, as shown in FIG. 1, the surface mount coil 50 is embedded in the insulating base 31 and sealed with the thermoplastic resin, and the terminal portion 52 of the surface mount coil 50 and the land 34 of the wiring board 30 are connected. It is possible to obtain the coil mounting substrate 10 that is electrically connected and in which the surface mount coil 50 and the heat dissipation member 70 are thermally connected by the first heat transfer path portion 35.

  Next, the effect of the characteristic part of the coil mounting board | substrate 10 shown to the said embodiment is demonstrated.

  In the coil mounting substrate 10 according to the present embodiment, the insulating base material 31 includes at least a thermoplastic resin, and the entire surface mount coil 50 is sealed by the thermoplastic resin of the insulating base material 31, and the insulating base material 31. The heat radiating member 70 is fixed to the surface. As described above, the coil mounting substrate 10 includes a plurality of resin films 32a to 32e, 33a to 33e, and at least every other thermoplastic resin film 32a to 32e. Laminate so as to be adjacent to the lower surface 51a, the upper surface 51b, and the heat dissipation member 70 of the main body 51, and pressurize and heat from above and below in the laminating direction by a vacuum hot press machine. Can do.

  In this method, 1) the terminal portion 52 and the land 34 are electrically connected and the surface-mounted coil 50 is embedded in the wiring board 30 (insulating base material 31) in a lump by the above pressing and heating. 2) The wiring board 30 can be formed. 3) The heat dissipation member 70 can be fixed to the wiring board 30. Therefore, the manufacturing process can be simplified.

  Moreover, the thermoplastic resin film 32b adjacent to the lower surface 51a of the main body 51 of the surface mount coil 50 is softened during the pressurization / heating described above, and flows under the applied pressure, thereby closely contacting the lower surface 51a. Thereby, it can suppress that an air layer is formed between the lower surface 51a of the main-body part 51, and the land formation surface (surface in which the land 34 of the thermosetting resin film 33a was formed) of the wiring board 30. FIG. . That is, the heat dissipation from the surface mount coil 50 to the heat dissipation member 70 is improved.

  As described above, in the coil mounting substrate 10 according to the present embodiment, the heat dissipation of the surface mount coil 50 is improved.

  In particular, in the present embodiment, the entire surface mount coil 50 is sealed with the thermoplastic resin of the insulating base 31. Therefore, the reliability of the surface mount coil 50 (for example, the connection reliability between the terminal portion 52 and the land 34) can be improved.

  Further, in the present embodiment, the wiring board 30 includes the interlayer connection via 36, is disposed in a facing region between the lower surface 51 a of the main body 51 of the surface mount coil 50 and the heat radiating member 70, and one end is connected to the heat radiating member 70. It has the 1st heat-transfer path | route part 35 electrically connected. According to this, the heat dissipation from the surface mount coil 50 to the heat dissipation member 70 can be improved by the first heat transfer path portion 35 as compared with the configuration in which only the insulating base material 31 is disposed in the facing region. .

  In particular, in the present embodiment, the surface (mounting surface) facing the land 34 in the surface mounting portion 52 a of the terminal portion 52 is disposed at a position closer to the land forming surface than the lower surface 51 a of the main body portion 51. In addition, the first heat transfer path portion 35 includes a plurality of interlayer connection vias 36, and the interlayer connection vias 36 (of the thermoplastic resin film 32b) disposed at the same position as the surface mounting portion 52a of the terminal portion 52 in the thickness direction. Interlayer connection via 36) is included. The end of the interlayer connection via 36 that forms the end opposite to the heat dissipation member 70 in the first heat transfer path 35 is in contact with the lower surface 51 a of the main body 51. Therefore, since the insulating base material 31 is not interposed between the surface mount coil 50 and the first heat transfer path portion 35, the heat dissipation from the surface mount coil 50 to the heat dissipation member 70 can be further improved.

  In the present embodiment, in the pressurizing / heating process, the wiring board 30 is formed, and the terminal portion 52 of the surface mount coil 50 and the land 34 are electrically and mechanically connected. However, the terminal portion 52 of the surface mount coil 50 and the land 34 may be electrically and mechanically connected before the lamination step. The manufacturing method is shown below.

  First, a thermosetting resin film 33a and a thermoplastic resin film 32b are prepared. As for the thermosetting resin film 33a, one having a copper foil stuck on one side is prepared, and this copper foil is patterned to form a conductor pattern including the land 34. Moreover, about the thermoplastic resin film 32b, the thing in which the cavity part 38 was formed is prepared.

  Next, by applying heat and pressure, the thermoplastic resin film 32 b is attached to the land forming surface of the thermosetting resin film 33 a so that the land 34 is positioned in the cavity 38. In the present embodiment, pressure is applied to the thermosetting resin film 33a side while heating so that the temperature of the thermoplastic resin film 32b is not less than the glass transition point of the thermoplastic resin constituting the film 32b and not more than the melting point. Then, the softened thermoplastic resin is brought into close contact with the land forming surface of the thermosetting resin film 33a.

  Next, via holes are formed in the resin films 32b and 33a, respectively, and a conductive paste 36a is filled in the via holes.

  Next, a separately prepared surface mount type coil 50 is positioned and placed on the thermoplastic resin film 32 b so that the terminal portions 52 are in contact with the corresponding lands 34 through the hollow portions 38. Then, as shown in FIG. 5, for example, the main body 51 of the surface mount coil 50 is pressurized toward the resin films 32 b and 33 a while being heated from the upper surface 51 a by a pulse heat type thermocompression bonding tool 100. As a result, heat from the thermocompression bonding tool 100 is transmitted to the terminal portion 52 of the surface mount coil 50, and the solder plating is melted, so that the surface mount portion 52a and the land 34 are mainly connected.

  Thus, after integrating the resin films 32b and 33a and the surface mount coil 50 into a unit, this unit is laminated with the other resin films 32a, 32c, 32d and 33b to 33e to form a laminated body. The coil mounting substrate 10 may be formed by performing a pressure / pressure process. According to this, since the terminal portion 52 of the surface mount coil 50 and the land 34 are connected before the lamination step, the connection reliability between the terminal portion 52 and the land 34 can be improved.

  In the above description, an example in which the via hole is formed after the thermoplastic resin film 32b is attached to the thermosetting resin film 33a and the conductive paste 36a is filled is shown. However, a via hole may be formed in each of the resin films 32b and 33a before being attached, and the conductive paste 36a may be filled.

  Moreover, in this embodiment, the surface mounting part 52a which has the mounting surface of the terminal part 52 showed the example arrange | positioned on the lower surface 51a of the main-body part 51 along the lower surface 51a. However, the arrangement of the surface mounting portion 52a having the mounting surface is not limited to the above example, and may be an arrangement extending in a direction away from the side surface 51c of the main body portion 51 in the vertical direction as shown in FIG. Moreover, as shown in FIG. 6, the mounting surface of the surface mounting part 52a is good also as a structure made into the substantially the same position as the lower surface 51a of the main-body part 51 in the thickness direction. Even when such a surface mount coil 50 is used, the configuration shown in the above embodiment can be employed.

(Second Embodiment)
In the first embodiment, the example in which the first heat transfer path portion 35 as the heat radiation wiring portion directly connects the three interlayer connection vias 36 is shown. However, the first heat transfer path portion 35 includes the interlayer connection via 36, is disposed in a region where the lower surface 51 a of the main body portion 51 of the surface mount coil 50 and the heat dissipation member 70 are opposed, and one end thereof is electrically connected to the heat dissipation member 70. As long as they are connected.

  In the present embodiment, as shown in FIG. 7, the first heat transfer path portion 35 is connected to a conductor pattern 39 different from the land 34 arranged on the land formation surface of the wiring board 30 and the conductor pattern 39. It is characterized by including an interlayer connection via 36.

  In the example shown in FIG. 7, a conductor pattern 39 is arranged on the land forming surface of the thermosetting resin film 33 a so as to be electrically separated from the land 34. The conductor pattern 39 is formed by patterning a conductor foil having a constant thickness together with the lands 34, and is disposed between the two lands 34 in one direction along the vertical direction.

  An interlayer connection via 36 is formed on the thermosetting resin film 33a with the conductor pattern 39 as a bottom, and one end of the interlayer connection via 36 of the thermosetting resin film 33a is connected to the interlayer connection via 36 of the thermoplastic resin film 32a. Connected with. One end of the interlayer connection via 36 of the thermoplastic resin film 32 a is connected to the heat dissipation member 70.

  According to this, the distance between the first heat transfer path portion 35 and the lower surface 51a of the body portion 51 of the surface mount coil 50 can be reduced by the amount of the conductor pattern 39 arranged on the land forming surface. In other words, the thickness of the insulating base 31 (the thermoplastic resin in the present embodiment) interposed between the first heat transfer path portion 35 and the lower surface 51a of the main body 51 can be reduced. Thereby, the heat dissipation from the surface mount coil 50 to the heat dissipation member 70 can be further improved.

  If the mounting surface position of the terminal portion 52 of the surface mount coil 50 is substantially the same as that of the lower surface 51 a of the main body 51, the conductor pattern 39 can be brought into contact with the lower surface 51 a of the main body 51. In this case, the insulating base 31 interposed between the first heat transfer path portion 35 and the lower surface 51a of the main body 51 can be eliminated.

(Third embodiment)
In each of the above embodiments, the example in which the wiring substrate 30 has the first heat transfer path portion 35 has been described. However, for example, as shown in FIG. 8, the wiring substrate 30 does not have the first heat transfer path portion 35 in the facing region between the lower surface 51 a of the main body portion 51 of the surface mount coil 50 and the heat radiating member 70, It is good also as a structure by which only the insulating base material 31 was interposed in the area | region.

  In the example shown in FIG. 8, thermoplastic resin films 32 a and 32 b and a thermosetting resin film 33 a are interposed in a facing region between the lower surface 51 a of the main body 51 of the surface mount coil 50 and the heat dissipation member 70. And, during the pressurization and heating shown in the first embodiment, the thermoplastic resin film 32b adjacent to the lower surface 51a of the main body 51 of the surface mount coil 50 is softened and flows under the applied pressure, so that the main body The part 51 is in close contact with the lower surface 51a.

  As described above, even in the configuration of the present embodiment, it is possible to suppress the formation of an air layer between the lower surface 51a of the main body 51 and the land formation surface of the wiring board 30. The heat dissipation from the mounting coil 50 to the heat dissipation member 70 is improved.

(Fourth embodiment)
In each of the above embodiments, the thermoplastic resin film is disposed between the resin film 33a (thermosetting resin film 33a) having a land forming surface on which the land 34 is disposed and the lower surface 51a of the main body 51 of the surface mount coil 50. An example is shown in which the lower surface 51a of the main body 51 is sealed by interposing 32b and the thermoplastic resin of the thermoplastic resin film 32b closely contacting the lower surface 51a of the main body 51.

  However, in the example shown in FIG. 9, a thermoplastic resin film 32 is employed as a resin film having a land forming surface on which lands 34 are arranged. According to this, in the pressurizing / heating process shown in the first embodiment, the thermoplastic resin of the thermoplastic resin film 32 having the land forming surface is softened and fluidized to be in close contact with the lower surface 51 a of the main body 51. For this reason, it can suppress that an air layer is formed between the lower surface 51a of the main-body part 51 and the land formation surface of the wiring board 30. FIG.

  In the example shown in FIG. 9, all of the plurality of resin films are thermoplastic resin films 32. Therefore, not only the resin film 32 having the land-forming surface but also the thermoplastic resin of the resin film 32 adjacent to the resin film 32 is softened / flowed in the pressurizing / heating process and is in close contact with the lower surface 51a of the main body 51. be able to. For this reason, it is possible to effectively suppress the formation of an air layer between the lower surface 51 a of the main body 51 and the land forming surface of the wiring board 30. Moreover, since all the resin films are the thermoplastic resin films 32, the structure of the insulating base material 31 can be simplified.

  In addition, although the structure which does not have the 1st heat-transfer path | route part 35 is shown in FIG. 9, the same effect is anticipated also in the structure which has the 1st heat-transfer path | route part 35 shown in 2nd Embodiment. be able to.

(Fifth embodiment)
In the present embodiment, the wiring board 30 is formed by connecting a plurality of interlayer connection vias directly or through a conductor pattern in the thickness direction, and is disposed to face the side surface of the main body, and one end is electrically connected to the heat radiating member 70. The point which has the 2nd heat-transfer path | route part 40 connected in general is made into the 1st characteristic. The second feature is that the plurality of second heat transfer path portions 40 are arranged with a predetermined interval and surround the side surface 51c of the main body portion 51 of the surface mount coil 50. Furthermore, the third heat transfer path is disposed so as to face the upper surface 51b of the main body 51, and the end of the second heat transfer path 40 opposite to the connection end of the heat dissipation member 70 is electrically connected. A point having a conductor pattern as the portion 43 is a third feature.

  In the example shown in FIGS. 10 and 11, for example, one more resin film constituting the insulating base 31 is included than the wiring substrate 30 shown in the first embodiment. Specifically, the surface 30 b of the wiring substrate 30 is included. The thermoplastic resin film 32f is arranged so as to form

  Interlayer connection vias 41 are formed in the thermoplastic resin films 32a to 32e and the thermosetting resin films 33a to 33e, respectively, and these interlayer connection vias 41 and conductors arranged on one side of the thermosetting resin films 33a to 33d. The pattern 42 constitutes a second heat transfer path portion 40 extending along the thickness direction. As shown in FIG. 10, the second heat transfer path portion 40 has an end portion opposite to the connection end with the heat radiating member 70 in the thickness direction, specifically, an interlayer formed on the thermosetting resin film 33e. One end of the connection via 41 is located farther from the heat dissipation member 70 than the upper surface 51 b of the main body 51.

  In addition, a plurality of second heat transfer path portions 40 are configured on the wiring board 30, and as shown in FIG. 11, each second heat transfer path portion 40 is arranged with a predetermined interval and is surface-mounted. The side surface 51c of the main body 51 of the coil 50 is surrounded.

  Each second heat transfer path portion 40 is connected to the heat radiating member 70 at one end thereof, specifically, one end of an interlayer connection via 41 formed in the thermoplastic resin film 32a. In addition, a conductor pattern as the third heat transfer path 43 is formed on the end opposite to the connection end of the heat radiating member 70, specifically on one end of the interlayer connection via 41 formed in the thermosetting resin film 33e. Electrically and mechanically connected. The conductor pattern forming the third heat transfer path portion 43 is opposed to the upper surface 51a of the main body 51 of the surface mount coil 50, that is, has a planar rectangular shape so as to include the projected portion of the surface mount coil 50 within the surface. It has a shape. In the present embodiment, the conductor pattern forming the third heat transfer path portion 43 is disposed on the surface of the thermosetting resin film 33e on the thermoplastic resin film 32f side.

  In addition, as shown in FIG. 11, the conductor pattern 44 that forms the wiring portion that is electrically connected to the land 34 passes through between the adjacent second heat transfer path portions 40, and thereby has a plurality of second heat transfer path portions. The inner peripheral region surrounded by 40 is drawn to the outer peripheral region.

  As shown in FIGS. 10 and 11, the wiring substrate 30 is configured with a first heat transfer path portion 35 as in the above embodiment.

  Thus, in the present embodiment, not only the first heat transfer path portion 35 but also the second heat transfer path portion 40 connected to the heat radiating member 70 is provided on the wiring board 30 so as to face the side surface 51c of the main body portion 51. ing. Thereby, the heat generated from the side surface 51 c of the main body 51 of the surface mount coil 50 can be transmitted to the heat dissipation member 70 via the insulating base 31 and the second heat transfer path 40. Therefore, the heat dissipation from the surface mount coil 50 to the heat dissipation member 70 can be further improved.

  In the present embodiment, the plurality of second heat transfer path portions 40 are arranged with a predetermined interval and surround the side surface 51 c of the main body portion 51 of the surface mount coil 50. According to this, the heat dissipation path from the side surface 51c of the main body 51 can be increased, and the heat dissipation can be improved. In addition, the conductor pattern 44 (electrical wiring) can be easily drawn from the land 34.

  In the present embodiment, the end of the second heat transfer path 40 opposite to the heat radiating member 70 is located farther from the heat radiating member 70 than the upper surface 51 b of the main body 51. A conductor pattern as the third heat transfer path portion 43 is connected to the end of the path portion 40 opposite to the heat dissipation member 70. Thereby, the heat generated from the upper surface 51b of the main body 51 of the surface mount coil 50 is transferred to the heat radiating member 70 via the insulating base 31, the third heat transfer path 43, and the second heat transfer path 40. Can communicate. Therefore, the heat dissipation from the surface mount coil 50 to the heat dissipation member 70 can be further improved.

  In the present embodiment, an example in which the plurality of second heat transfer path portions 40 including the interlayer connection via 41 having a circular cross section is arranged with a predetermined interval as shown in FIG. However, the number of second heat transfer path portions 40 is not limited to the above example. For example, as shown in FIG. 12, two second heat transfer path portions 40 including interlayer connection vias 41 having a substantially U-shaped cross section are employed so as to surround the side surface 51c of the main body portion 51 of the surface mount coil 50. You can also.

  Moreover, although not shown in figure, the cylindrical 2nd heat-transfer path | route part 40 can also be employ | adopted so that the side 51c of the main-body part 51 of the surface mount type coil 50 may be surrounded. In this case, all resin films having a conductor pattern 42 (conductor foil) provided on at least one surface are adopted, and an annular via hole is formed with the conductor pattern 42 as a bottom to form an annular interlayer connection via 41. For example, it is possible to prevent the inner peripheral portion of the via hole from falling off in the resin film. In this configuration, the wiring part electrically connected to the land 34 is connected to at least one of the second heat transfer path part 40 and the third heat transfer path part 43 with the second heat transfer path part 40 and the third heat transfer path part 43. What is necessary is just to provide the hole part for taking out out of the area | region enclosed by the thermal pathway part 43 and the heat radiating member 70. FIG.

  In addition, although the example which has the 1st heat-transfer path | route part 35 was shown in this embodiment, it is good also as a structure which does not have the 1st heat-transfer path | route part 35. FIG.

  Further, in the present embodiment, an example in which the third heat transfer path portion 43 is embedded in the insulating base material 31 is shown, but the configuration exposed from the insulating base material 31, that is, the surface 30b of the wiring board 30 is third. It is good also as a structure by which the conductor pattern which makes the heat-transfer path | route part 43 is arrange | positioned. According to this, although the 3rd heat transfer path part 43 is exposed outside, it becomes easy to radiate heat outside the coil mounting substrate 10.

(Sixth embodiment)
Also in the present embodiment, as in the fifth embodiment, one end of the second heat transfer path portion 40 disposed surrounding the side surface 51c of the main body 51 of the surface mount coil 50 is electrically and mechanically connected to the heat radiating member 70. The other end is electrically and mechanically connected to the third heat transfer path portion 43. In this embodiment, as shown in FIG. 13, a potential fixing terminal portion 45 that is exposed to the outside from the insulating base 31 and fixes the second heat transfer path portion 40 to a predetermined potential (for example, ground potential). It is characterized by comprising.

  In the example shown in FIG. 13, the potential fixing terminal portion 45 is configured by a conductor pattern arranged on the same plane as the conductor pattern forming the third heat transfer path portion 43. The second heat transfer path 40 and the potential fixing terminal 45 are electrically connected by the conductor pattern 46a including the conductor pattern drawn from the conductor pattern 42 constituting the second heat transfer path 40 and the interlayer connection via 46b. It is connected to the. An opening 47 is formed in the thermoplastic resin film 32 f with the potential fixing terminal 45 as the bottom, and the potential fixing terminal 45 is exposed to the outside through the opening 47.

  As described above, according to the present embodiment, the potential fixing terminal portion 45 exposed to the outside is electrically connected to a constant voltage source such as a ground line or a power supply line, whereby the second heat transfer path section 40 and the The part electrically connected to the second heat transfer path 40, in the present embodiment, the third heat transfer path 43, the heat radiating member 70, and the first heat transfer path 35 may be fixed to a predetermined potential. it can. Accordingly, noise radiated from the surface mount coil 50 to the space can be shielded.

  In the example shown in FIG. 13, the first heat transfer path portion 35 shown in the first embodiment is configured on the wiring board 30. The first heat transfer path portion 35 is in contact with the lower surface 51 a of the main body 51 of the surface mount coil 50. In such a configuration, an electrical insulating member is interposed between the core and the coil forming the main body 51 of the surface mount coil 50 and the first heat transfer path 35, and the core and the coil and the first heat transfer path 35. 35 may be electrically separated. As the electrical insulating member, for example, when the core forms the outline of the main body 51, an insulating film provided on the lower surface 51a of the main body 51 can be employed. Moreover, when the core and the coil are resin-molded, the mold resin can be used as an electrical insulating member.

  Moreover, in this embodiment, although the example which makes the conductor pattern arrange | positioned on the same surface as the conductor pattern which comprises the 3rd heat-transfer path | route part 43 the electric potential fixing terminal part 45 was shown, the electric potential fixing terminal part 45 is shown in FIG. It is not limited to the above example. What is necessary is just to be electrically connected with the 2nd heat-transfer path | route part 40, and to be exposed outside the coil mounting board | substrate 10 (wiring board 30). When the third heat transfer path portion 43 is exposed to the outside without having the thermoplastic resin film 32f, the third heat transfer path portion 43 may be used as the potential fixing terminal portion 45. Further, the heat radiating member 70 may be the potential fixing terminal portion 45.

  Moreover, although the example which has the 1st heat-transfer path | route part 35 was shown in this embodiment, it is good also as a structure which does not have the 1st heat-transfer path | route part 35. FIG.

(Seventh embodiment)
In 5th Embodiment and 6th Embodiment, although the wiring board 30 showed the example which has a conductor pattern as the 3rd heat transfer path part 43, as shown in FIG. It is good also as a structure which does not have.

  In the example shown in FIG. 14, the end of the second heat transfer path portion 40 on the side opposite to the heat radiating member 70 is more radiant than the upper surface 51 b of the main body 51 of the surface mount coil 50 in the thickness direction. It is said to be far from the location. Thus, if the structure where the 2nd heat-transfer path | route part 40 extended long is employ | adopted, the heat dissipation from the surface mount type coil 50 to the heat radiating member 70 can be improved. However, the second heat transfer path portion 40 only needs to face at least a part of the side surface 51 c of the main body portion 51.

  In FIG. 14, the first heat transfer path 35 is shown together with the second heat transfer path 40, but the first heat transfer path 35 may not be provided.

(Eighth embodiment)
In each of the above-described embodiments, the example in which the entire surface mount coil 50 is sealed with the thermoplastic resin of the insulating base 31 has been described. In contrast, in the present embodiment, for example, as shown in FIG. 15, the wiring board 30 has a recess 48 having a predetermined depth that opens on a surface 30 b opposite to the arrangement surface 30 a of the heat dissipation member 70. The surface mount type coil 50 is disposed in the recess 48 from the lower surface 51a side of the main body 51, and the upper surface 51b of the main body 51 is in the same position as the surface 30b of the wiring board 30 in the thickness direction. Thereby, in this embodiment, the upper surface 51b of the main-body part 51 is exposed outside.

  A gap between the side wall of the recess 48 and the side surface 51c of the main body 51 of the surface mount coil 50 is filled with a potting material 90 having electrical insulation and higher thermal conductivity than the insulating base 31. ing. As such a potting material 90, a silicon gel for heat dissipation can be employed.

  When such a configuration is adopted, heat dissipation from the side surface 51c of the main body 51 can be improved as compared with a configuration in which the side 51c of the main body 51 is sealed with a thermoplastic resin.

  In the example shown in FIG. 15, among the conductor patterns 42 constituting the second heat transfer path portion 40, the conductor pattern 42 at the same position as the recess 48 in the thickness direction is extended in the side wall direction of the recess 48, The end 42 a forms the side wall of the recess 48. For this reason, the heat of the surface-mounted coil 50 is transmitted from the potting material 90 to the second heat transfer path portion 40, and heat dissipation can be improved.

  The above-described coil mounting substrate 10 can be formed basically using the manufacturing method shown in the first embodiment. The difference is that, when the wiring substrate 30 is formed after the pressurizing / heating step is completed, as shown in FIG. 16, 1) the wiring substrate 30 has a recess 48 having a predetermined depth that opens to the surface 30b. 2) The surface mount coil 50 is disposed in the recess 48, and the upper surface 51b of the main body 51 is exposed to the same position as the surface 30b of the wiring board 30. 3) The side wall of the recess 48 In determining the shape of the resin film (cavity) and the arrangement with respect to the surface mount coil 50 so that a predetermined space (gap) exists between the side surface 51c of the main body 51 of the surface mount coil 50. is there. Then, after the pressurizing / heating process is finished, the potting material 90 is injected into the recess 48 of the wiring board 30 shown in FIG. 16 and solidified, whereby the coil mounting board 10 shown in FIG. 15 can be obtained.

  In the present embodiment, at the time of the laminated body, the surface mounting type coil 50 is disposed in the recess 48 so that the surface mounting portion 52a of the terminal portion 52 contacts the corresponding land 34, and the upper surface 51a of the main body portion 51 is connected to the wiring board. It becomes substantially the same position in the thickness direction as the surface of the thermosetting resin film 33d forming the surface 30b of 30. Therefore, the flat surface of one press plate of the vacuum heat press machine is in contact with both the upper surface 51b of the main body 51 of the surface mount coil 50 and the surface of the thermosetting resin film 33d, and heats the laminate while pressing it. be able to. Therefore, the terminal portion 52 of the surface mount coil 50 can be electrically and mechanically connected to the land 34, and the wiring board 30 can be formed.

  Moreover, in FIG. 15, although the 1st heat-transfer path | route part 35 and the 2nd heat-transfer path | route part 40 are shown together, the structure which has only any one is also employable. Moreover, the structure which has neither can be employ | adopted. Furthermore, it can be combined with the configuration having the potential fixing terminal portion 45 shown in the sixth embodiment. The shielding effect by at least the 2nd heat-transfer path | route part 40 and the thermal radiation member 70 can be anticipated.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The structure of the several resin film which comprises the insulating base material 31 is not limited to the said example. The number of resin films is not limited to the above example. Any number may be used as long as the surface mount coil 50 can be embedded.

  The constituent material of the thermoplastic resin film is not limited to the above example. For example, even if it consists of PEEK / PEI, you may employ | adopt the thing from which a ratio differs from the said example. In addition, constituent materials other than PEEK / PEI, such as liquid crystal polymer (LCP), polyphenylene sulfide (PPS), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) ) Etc. may be adopted. Moreover, the thermoplastic resin film containing the inorganic material used for base materials, such as glass fiber and an aramid fiber, and the inorganic filler added in order to adjust melting | fusing point and a linear expansion coefficient is also employable.

  The constituent material of the thermosetting resin film is not limited to the above example. For example, a film containing an inorganic material used for a substrate such as glass fiber or aramid fiber can also be employed. Also, a thermosetting resin other than the thermosetting polyimide can be employed.

  Moreover, it is good also as a structure which does not contain a thermosetting resin film but contains only a thermoplastic resin film as a several resin film. Alternatively, the number of thermoplastic resin films may be larger than that of the thermosetting resin film, and the thermoplastic resin film may be partially continuous in the laminated state.

  Moreover, although the heat radiating member 70 is provided on the entire surface 30a of the wiring substrate 30, the heat radiating member 70 may be fixed to a part of the surface 30a. Moreover, it is good also as a structure by which the heat radiating member 70 was each fixed to both surfaces 30a, 30b of the wiring board 30.

  Further, the thickness of the resin film and the thickness of the conductor pattern are not limited to the above examples. However, in the thickness direction, the thermoplastic resin film that is adjacent to the main body 51 of the surface mount coil 50 and seals the surface mount coil 50 has a thickness of 5 μm or more as described above. It is preferable.

DESCRIPTION OF SYMBOLS 10 ... Coil mounting board | substrate 30 ... Wiring board 31, 31a-31e, 32a-32e ... Resin film 33 ... Land 35 ... 1st heat-transfer path | route part 40 ... 2nd heat-transfer Path part 43 ... third heat transfer path part 50 ... surface mount coil 51 ... body part 52 ... terminal part 70 ... heat dissipation member 90 ... potting material

Claims (16)

An insulating base material, a conductor pattern disposed on the insulating base material and extending in a direction perpendicular to the thickness direction of the insulating base material, and a conductor filled in a via hole of the insulating base material, An interlayer connection via extending in the thickness direction of the insulating base, and a wiring board including a land as the conductor pattern;
A main body portion including a core and a coil, and a land formed at the same position as the lower surface facing the land forming surface of the main body portion or in the thickness direction of the insulating base material in the thickness direction of the insulating base material or at the land than the lower surface A surface-mounting coil having a mounting portion disposed at a position close to the surface, the terminal portion being electrically connected to a land of the wiring board,
A heat dissipating member that includes a metal material and is disposed on one of the surfaces of the wiring board that is perpendicular to the thickness direction of the insulating base and that faces the lower surface of the main body. ,
The insulating base material is such that the thermoplastic resin film containing a thermoplastic resin is adjacent to the lower surface of the main body portion of the surface mount coil and the heat radiating member while being positioned at least every other sheet. Laminating and integrating multiple resin films including
The wiring board has the land forming surface between the disposition surface of the heat radiating member and the surface opposite to the disposition surface in the thickness direction of the insulating base material,
The surface mount coil is embedded in the insulating base material so as not to protrude from a surface opposite to the heat dissipating member placement surface of the wiring board in the thickness direction of the insulating base material, and the lower surface of the main body portion is A coil mounting substrate, wherein the insulating substrate is sealed with a thermoplastic resin.   The wiring board includes the interlayer connection via, and is disposed in a facing region between the lower surface of the main body and the heat dissipation member, and has a first heat transfer path portion that is electrically connected to the heat dissipation member at one end. The coil mounting substrate according to claim 1.   The said 1st heat-transfer path | route part contains the conductor pattern different from the said land arrange | positioned at the said land formation surface, and the interlayer connection via | veer connected to this conductor pattern. Coil mounting board. The mounting surface of the terminal portion is disposed at a position closer to the land forming surface than the lower surface of the main body portion,
The first heat transfer path portion includes a plurality of the interlayer connection vias, includes an interlayer connection via disposed at the same position as the terminal portion in the thickness direction of the insulating base, and is connected to the heat dissipation member. The coil mounting substrate according to claim 2, wherein an end portion of the interlayer connection via forming an end portion on the opposite side of the main body portion is in contact with the lower surface of the main body portion.   The wiring board is formed by connecting a plurality of the interlayer connection vias directly or through the conductor pattern in the thickness direction of the insulating base material, and is disposed to face the side surface of the main body, with one end thereof being the heat dissipation The coil mounting substrate according to any one of claims 2 to 4, further comprising a second heat transfer path portion electrically connected to the member.   The coil mounting substrate according to claim 5, wherein the second heat transfer path portion is disposed so as to surround a side surface of the main body portion of the surface mount coil.   The coil mounting substrate according to claim 6, wherein the plurality of second heat transfer path portions are arranged with a predetermined interval and surround a side surface of the main body portion of the surface mounting type coil. The core and coil of the surface mount coil and the first heat transfer path are electrically separated,
The coil mounting substrate according to claim 6 or 7, further comprising a potential fixing terminal portion that is exposed to the outside from the insulating base material and fixes the second heat transfer path portion to a predetermined potential. . In the thickness direction of the insulating base material, the second heat transfer path portion has an end portion on the side opposite to the connection end with the heat radiating member, and the heat radiating member on the side opposite to the lower surface of the main body portion. Is far from
The wiring board is arranged to face the upper surface of the main body, and a third heat transfer unit in which an end of the second heat transfer path unit opposite to the connection end of the heat radiating member is electrically connected. It has the said conductor pattern as a path | route part, The coil mounting board | substrate of any one of Claims 6-8 characterized by the above-mentioned.   The wiring board is formed by connecting a plurality of the interlayer connection vias directly or through the conductor pattern in the thickness direction of the insulating base material, and is disposed to face the side surface of the main body, with one end thereof being the heat dissipation The coil mounting board according to claim 1, further comprising a second heat transfer path portion electrically connected to the member.   The coil mounting substrate according to claim 10, wherein the second heat transfer path portion is disposed so as to surround a side surface of the main body portion of the surface mount coil.   The coil mounting substrate according to claim 11, wherein the plurality of second heat transfer path portions are arranged with a predetermined interval and surround a side surface of the main body portion of the surface mounting type coil.   The coil mounting substrate according to claim 11, further comprising a potential fixing terminal portion that is exposed to the outside from the insulating base material and fixes the second heat transfer path portion to a predetermined potential. . In the thickness direction of the insulating base material, the second heat transfer path portion has an end opposite to the connection end with the heat radiating member at the same position as the upper surface opposite to the lower surface of the main body portion or the It is a position farther from the heat dissipation member than the upper surface of the main body,
The wiring board is arranged to face the upper surface of the main body, and a third heat transfer unit in which an end of the second heat transfer path unit opposite to the connection end of the heat radiating member is electrically connected. It has the said conductor pattern as a path | route part, The coil mounting board | substrate of any one of Claims 11-13 characterized by the above-mentioned. The insulating substrate includes a plurality of the resin films such that the thermoplastic resin film is adjacent to the lower surface of the body portion of the surface mount coil, the upper surface opposite to the lower surface, and the heat radiating member. Layered and integrated,
The coil mounting board according to any one of claims 1 to 14, wherein the entire surface mounting coil is sealed with a thermoplastic resin of the insulating base material. The wiring board has a recess opening on a surface opposite to the surface on which the heat dissipating member is disposed,
The surface mount coil is disposed in the recess, and an upper surface opposite to the lower surface of the main body portion is a surface opposite to a heat dissipating member arrangement surface of the wiring board in the thickness direction of the insulating base. The gap between the side wall of the recess and the side surface of the surface mount coil is filled with a potting material having electrical insulation and higher thermal conductivity than the insulating base material. The coil mounting substrate according to any one of claims 1 to 8, and 10 to 13.

Images