JP2003224235A - Wiring board with heat sink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board with a heat sink, wherein the wiring board and the heat sink are firmly bonded together through the intermediary of a bonding layer formed of a conductive resin, and a grounding part or a power supply conductor layer provided to the wiring board is electrically, stably, and well connected to the heat sink. <P>SOLUTION: A grounding layer or a power supply conductor layer 6 is deposited on the underside of a wiring board 1, an insulating layer 12 formed of a thermosetting resin is partially deposited so as to make a part of the grounding layer or the power supply conductor layer 6 exposed, and a metal heat sink 2 is bonded to the grounding layer or the power supply conductor layer 6 and the insulating layer 12 through the intermediary of a bonding layer 15 formed of conductive filler and thermosetting resin for the formation of the wiring board with the heat sink. Projections 2a are provided on the top surface of the heat sink 2 as they are protruding upright, corresponding to the exposed parts of the grounding part or the power supply conductor layer 6. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a wiring board with a radiator plate used for a package for housing a semiconductor element such as a semiconductor integrated circuit element. is there. 2. Description of the Related Art Conventionally, a wiring board with a heat radiating plate used for a semiconductor element housing package for housing a semiconductor element such as an MPU has a central portion as shown in FIG. Stepped through hole 21a for accommodating semiconductor element 20
And a through hole in the lower surface of the wiring board 21.
A heat radiation plate 22 made of a metal material such as copper and having flat upper and lower surfaces having a mounting portion 22a on which a semiconductor element 20 is mounted at the center of the upper surface is bonded mainly through a bonding layer 23 so as to close the upper surface 21a. Is configured. In this conventional wiring board with a heat sink, the wiring board 21 is made of two insulating plates 24 and 25 made of glass cloth impregnated with a thermosetting resin such as an epoxy resin.
Are laminated via an adhesive layer 26 made of a glass cloth impregnated with a thermosetting resin such as an epoxy resin. In the insulating plate 24, a through hole 24a slightly larger than the semiconductor element 20 is formed at the center thereof, and the wiring conductor layer 27 and the substantially entire lower surface thereof extend from the periphery of the through hole 24a on the upper surface to the outer peripheral portion. A ground or power supply conductor layer 28 is attached, and a through hole 25a larger than the through hole 24a is formed in the center of the insulating plate 25, and an external connection conductor 29 is attached on the upper surface. . A plurality of through holes 30 are formed in the outer peripheral portions of the insulating plates 24 and 25 and the adhesive layer 26.
A through conductor 31 that electrically connects the wiring conductor layer 27 and the ground or power supply conductor layer 28 to the external connection conductor 29 is attached to the inner wall of the through hole 30. Further, a part of the grounding or power supply conductor layer 28 and the heatsink 22 are firmly bonded to a part of the grounding or power supply conductor layer 28 and a part where the through conductor 31 is exposed on the lower surface of the wiring board 21. In addition, an insulating layer 32 made of epoxy resin is applied to prevent unnecessary electrical short circuit between the heat sink 22 and the wiring conductor layer 27. Then, the ground or power supply conductor layer 28 and the insulating layer 32
On the lower surface of the heat sink 22 is a bonding layer 23 made of a conductive adhesive resin such as an epoxy resin containing a conductive filler such as a metal powder.
And the ground or power supply conductor layer 28 and the heat sink 22
Are electrically conducted by the bonding layer 23. According to the conventional wiring board with a heat sink, the semiconductor element 20 is mounted on the mounting portion 22a of the heat sink 22 and each electrode of the semiconductor element 20 is connected to the wiring conductor layer 27.
Are electrically connected to each other through an electrical connection means such as a bonding wire 33. Thereafter, an external connection member 34 made of a solder ball or the like is joined to the external connection conductor 29 and the through hole 21 is formed.
A semiconductor device as a product is obtained by potting a sealing resin (not shown) into a and hermetically sealing the semiconductor element 20. In order to join the heat radiating plate 22 to the lower surface of the wiring board 21 via the bonding layer 23, the uncured surface is attached to the lower surface of the wiring board 21 on which the grounding or power supply conductor layer 28 and the insulating layer 32 are applied. A conductive adhesive paste composed of a mixture of a thermosetting resin and a conductive filler is applied by printing, and the heat-radiating plate 22 is brought into contact with the conductive adhesive paste and the conductive adhesive paste is pressed from above and below. Has been adopted. However, according to this conventional wiring board with a heat sink, the insulating layer 32 is partially applied to the ground of the wiring board 21 or the lower surface of the power supply conductor layer 28. Therefore, although the wiring board 21 and the heat sink 22 are firmly joined by the insulating layer 32 via the joining layer 23, the insulating layer is located between the lower surface of the ground or power supply conductor layer 28 and the lower surface of the insulating layer 32. Since a step having a height corresponding to the thickness of 32 is formed, and the upper surface of the heat sink 22 is flat, the thickness of the bonding layer 23 made of a conductive resin is reduced to the ground or power supply conductor layer.
It becomes thick at a portion where it is joined to the heat sink 28, and the electrical resistance between the ground or power supply conductor layer 28 and the heat sink 22 is increased by such a thick joint layer 23. Further, when the wiring board 21 and the heat sink 22 are joined, the joining layer 23 and the ground or the power supply conductor layer 28 are not satisfactorily pressed against each other, and a void or poor adhesion is likely to occur between them. Therefore, there is a problem that it is difficult to electrically and satisfactorily connect the heat sink 22 to the ground or the power supply conductor layer 28. The present invention has been devised in view of such a conventional problem, and an object of the present invention is to enable a wiring board and a heat sink to be firmly joined via a joining layer made of a conductive resin. Another object of the present invention is to provide a wiring board with a heat sink that can electrically and stably connect the ground or power supply conductor layer of the wiring board to the heat sink. A wiring board with a heat sink according to the present invention has an insulating substrate having a through hole for accommodating a semiconductor element in a central portion, and an outer peripheral surface from an upper surface around the through hole of the insulating substrate. A wiring conductor layer applied over the portion, a ground or power supply conductor layer attached to the lower surface of the insulating substrate, and a portion of the ground or power supply conductor layer exposed on the lower surface of the ground or power supply conductor layer. An insulating layer made of a thermosetting resin partially adhered to the conductive filler and the thermosetting resin so as to cover the through hole in the exposed portion of the grounding or power supply conductor layer and the insulating layer. And a metal heat radiating plate joined via a bonding layer made of a heat radiating plate, wherein the heat radiating plate has a projection projecting on an upper surface thereof corresponding to the exposed portion. Characterized by Things. According to the semiconductor device housing package of the present invention, since the insulating layer made of a thermosetting resin is partially applied to the lower surface of the ground or power supply conductor layer, the insulating layer and the bonding layer are formed. The heat sink is firmly joined to the lower surface of the insulating substrate on which the ground or power supply conductor layer is adhered. In addition, since the projecting portion is provided on the upper surface of the heat sink corresponding to the exposed portion of the grounding or power supply conductor layer, the thickness of the bonding layer does not increase at the portion where the grounding or power supply conductor layer is joined, Therefore, the ground or power supply conductor layer and the heat sink can be connected with a low electric resistance via the bonding layer. Further, when the wiring board and the heat sink are joined via the joining layer, the grounding or the power supply conductor layer and the joining layer are sufficiently pressed against each other by the projection, so that a void or poor adhesion occurs between the two. Therefore, both can be connected electrically and satisfactorily and stably. Next, a wiring board with a heat sink of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment of a wiring board with a heat sink of the present invention. In the drawing, reference numeral 1 denotes a wiring board, and 2 denotes a heat radiating plate. These mainly constitute a wiring board with a heat radiating plate for mounting the semiconductor element 3. In this example, a through hole 4a for forming a space for accommodating the semiconductor element 3 in the center is provided.
An insulating plate 4 having a wiring conductor layer 5 on the upper surface and a grounding or power supply conductor layer 6 on the lower surface, a through hole 7a larger than the through hole 4a in the center, and an external connection conductor 8 on the upper surface. This shows an example in which the wiring board 1 is formed by bonding the attached insulating plate 7 through an adhesive layer 9.
A plurality of through holes 10 are formed in the outer peripheral portion of the wiring board 1, and a through conductor 11 is attached to an inner wall of the through hole 10. Note that the ground or power supply conductor layer 6 is electrically connected to either the ground electrode or the power supply electrode of the semiconductor element 3 and thereby functions as a ground conductor layer or as a power supply conductor layer. The insulating plates 4 and 7 constituting the wiring board 1 are in a substantially rectangular frame shape formed by impregnating a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin into a cloth of glass fiber or aramid fiber, for example. In addition to functioning as a support for the wiring conductor layer 5, the ground or power supply conductor layer 6, and the external connection conductor 8, a space for accommodating the semiconductor element 3 is formed in the through holes 4a, 7a. The insulating plates 4 and 7 are formed by, for example, obtaining a sheet in which a glass cloth is impregnated with a thermosetting resin such as an uncured epoxy resin, and thermosetting the sheet to form a through hole. 4a and 7a are formed by cutting the cured insulating plates 4 and 7. The bonding layer 9 for bonding the insulating plates 4 and 7 is formed by impregnating a cloth made of glass fiber or aramid fiber with a thermosetting resin such as epoxy resin or bismaleimide triazine resin. It functions as a bonding member for bonding the insulating plates 4 and 7 together. The insulating plates 4 and 7
Means that a sheet for the adhesive layer 9 formed by impregnating a cloth made of glass fiber or the like with a thermosetting resin such as an uncured epoxy resin is sandwiched between the insulating plates 4 and 7 and is thermally cured. Thus, the bonding is performed via the bonding layer 9. Wiring conductor layer 5 adhered to upper surface of insulating plate 4
Is formed of a metal such as copper foil, and is formed in a plurality of band-shaped patterns from the vicinity of the opening of the through hole 4a to the outer peripheral portion. The wiring conductor layer 5 functions as a part of a conductive path for electrically connecting each electrode of the semiconductor element 3 to an external electric circuit, and each electrode of the semiconductor element 3 is bonded to a portion near the through hole 4a. The connection is made via a wire 13, and the outer periphery thereof is connected to the through conductor 11. The ground or power supply conductor layer 6 adhered to the lower surface of the insulating plate 4 is made of metal such as copper foil.
Is formed on substantially the entire lower surface of the substrate. The ground or power supply conductor layer 6 has a function of supplying a ground or power supply potential to the semiconductor element 3 and adjusting the characteristic impedance of the wiring conductor layer 5 to a predetermined value, and is electrically connected to the through conductor 11. ing. The wiring conductor layer 5 and the grounding or power supply conductor layer 6 are formed by attaching copper foil to the upper and lower surfaces of an uncured sheet for the insulating plate 4 and curing the sheet. The copper foil adhered to the sheet is formed by etching a predetermined pattern by a photolithography technique. If the inner edge of the grounding or power supply conductor layer 6 is provided 0.1 to 5 mm on the outer peripheral side of the opening of the through hole 4a of the insulating plate 4, the through hole 4a is formed in the insulating plate 4. As a result, no burrs are formed on the ground or power supply conductor layer 6, thereby effectively preventing the ground or power supply conductor layer 6 from coming into contact with the semiconductor element 3 when the semiconductor element 3 is mounted. In addition, it is possible to prevent the semiconductor element 3 from operating unnecessarily by preventing unnecessary electrical short-circuiting between the semiconductor element 3 and the ground or the power supply conductor layer 6 or a decrease in electrical insulation. Therefore, it is preferable that the grounding or power supply conductor layer 6 be provided with its inner edge located on the outer peripheral side by about 0.1 to 5 mm from the opening of the through hole 4a. The distance between the inner edge of the ground or power supply conductor layer 6 and the opening of the through hole 4a is 0.1 m.
If it is shorter than m, the risk of burrs occurring in the ground or power supply conductor layer 6 when processing the through hole 4a tends to increase, while the inner edge of the ground or power supply conductor layer 6 and the opening of the through hole 4a If the distance to the ground is longer than 5 mm, the ground or the power supply conductor layer 6 cannot be secured with a sufficient area,
A sufficiently stable ground or power supply potential cannot be supplied to the semiconductor element 3, and it tends to be difficult to adjust the characteristic impedance of the wiring conductor layer 5 to a predetermined value. The external connection conductor 8 attached to the upper surface of the insulating plate 7 functions as a connection conductor with an external electric circuit, and is formed so as to be electrically connected to the through conductor 11. An external connection member 14 made of a solder ball or the like is attached to the external connection conductor 8. The external connection conductor 8 is made of copper foil like the wiring conductor layer 5 and the grounding or power supply conductor layer 6. The copper foil is stuck on the uncured sheet for the insulating plate 7 and After curing, the copper foil adhered to the sheet is formed into a predetermined pattern by photolithography technology. The wiring conductor layer 5 and the external connection conductor 8
Usually has a thickness of about 5 to 50 μm. The thickness is preferably 5 μm or more from the viewpoint of transmitting a high-speed signal, and is preferably 50 μm or less in order to process the wiring conductor layer 5 and the external connection conductor 8 with high dimensional accuracy. The wiring conductor layer 5 and the external connection conductor 8
In general, a nickel plating layer having a thickness of about 1 to 30 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially applied to the exposed surface by electroless plating or electrolytic plating. Thereby, oxidation corrosion of the wiring conductor layer 5 and the external connection conductor 8 can be effectively prevented, and the electrical connection between the wiring conductor layer 5 and the bonding wire 13 and the connection between the external connection conductor 8 and the external connection member 14 can be prevented. Good electrical connection can be achieved. The through conductor 11 attached to the inner wall of the through hole 10 functions as a connection conductor for electrically connecting the wiring conductor layer 5 or the grounding or power supply conductor layer 6 to the external connection conductor 8. 1 is formed by applying an electroless plating method or an electrolytic plating method to a copper plating layer having a thickness of about 4 to 50 μm on the inner wall of a large number of through holes 10 formed from the upper surface to the lower surface. The thickness of the through conductor 11 is 4
If it is less than μm, the wiring conductor layer 5 or the ground or power supply conductor layer 6
And the external connection conductor 8 tend to be difficult to electrically connect well. On the other hand, if it exceeds 50 μm, it takes a long time to form the through conductor 11 having such a thickness,
The efficiency of manufacturing the wiring board 1 tends to be extremely low. Further, an insulating layer 12 made of a thermosetting resin such as an epoxy resin is provided on the lower surface of the wiring board 1 on which the ground or power supply conductor layer 6 is adhered, for example, to partly connect the ground or power supply conductor layer 6. It is partially formed so as to be exposed in a frame shape. The insulating layer 12 functions as a joining base member for firmly joining the heat radiating plate 2 to the insulating substrate 1, and the heat radiating plate 2 is formed of a conductive filler and a thermosetting resin on the grounding or power supply conductor layer 6 and the insulating layer 12. A conductive bonding layer 15 comprising
The insulating substrate 1 and the heat radiating plate 2 are joined together through the connection, and the grounding or power supply conductor layer 6 and the heat radiating plate 2 are electrically connected. The insulating layer 12 contains 5 inorganic fillers made of an inorganic insulating powder such as silica.
You may make it contain about 50 weight%. By including such an inorganic filler, the thermal expansion coefficient of the insulating layer 12 can be adjusted, and the heat resistance and the like of the insulating layer 12 can be improved. Such an insulating layer 12 is formed by applying a thermosetting resin paste such as an uncured epoxy resin to the wiring board 1.
After being partially applied to the lower surface of the substrate, it is formed by heat curing. In the wiring board with a heat sink of the present invention, the insulating layer 12 made of a thermosetting resin is provided on the lower surface of the ground or power supply conductor layer 6 such that a part of the ground or power supply conductor layer 6 is exposed. Since the insulating layer 12 is partially applied, the ground or power supply conductor layer 6 on which the insulating layer 12 is applied is formed.
And the radiator plate 2 are firmly joined via the joining layer 15. At this time, the insulating layer 12 partially applied to the ground or power supply conductor layer 6 is an anchor for firmly fixing the bonding layer 15 made of a conductive filler and a thermosetting resin to the ground or power supply conductor layer 6. , And the thermosetting resin in the insulating layer 12 and the thermosetting resin in the bonding layer 15 are firmly bonded to each other, thereby improving the adhesion between the grounding or the power supply conductor layer 6 and the bonding layer 15. it can. In this case, by setting the area ratio of the insulating layer 12 to the lower surface of the grounding or power supply conductor layer 6 to 5% to 40%, the adhesion between the grounding or power supply conductor layer 6 and the bonding layer 15 is particularly improved. I do. If the area ratio of the insulating layer 12 to the lower surface of the grounding or power supply conductor layer 6 is less than 5%, the effect of the insulation layer 12 as an anchor is small, and
It tends to be difficult to firmly adhere the bonding layer 15 and the bonding layer 15. On the other hand, if it is more than 40%, the bonding area between the grounding or the power supply conductive layer 6 and the conductive bonding layer 15 decreases, and The electric resistance between the power supply conductor layer 6 and the radiator plate 2 is slightly increased, which makes it difficult to stably connect the radiator plate 2 to the ground or the power supply potential. In this example, the insulating layer 12 is attached so as to expose a part of the lower surface of the ground or power supply conductor layer 6 in a frame shape. The lower surface may be attached so as to partially expose the lower surface in a grid or dot shape. On the other hand, the heat radiating plate 2 joined to the lower surface of the wiring board 1 via the joining layer 15 is made of a metal having excellent thermal conductivity such as copper and is joined so as to close the through hole 4a. The heat radiating plate 2 functions as a support for supporting the semiconductor element 3 and also functions as a heat radiating member for radiating heat generated during operation of the semiconductor element 3 to the outside. It has a mounting portion 2a for mounting the semiconductor element 3. And this mounting part 2a
The semiconductor element 3 is bonded and fixed via an adhesive such as a conductive epoxy resin. The heat radiating plate 2 is formed by punching a plate made of, for example, copper into a predetermined shape by a press die, or by performing an etching process. If a metal having good corrosion resistance, such as nickel or gold, is applied to the surface of the heat radiating plate 2 to a thickness of 1 to 20 μm by plating, oxidation corrosion of the heat radiating plate 2 can be effectively prevented. Further, in order to improve the bonding strength between the heat radiating plate 2 and the bonding layer 15, the surface of the heat radiating plate 2 is subjected to a blackening treatment or a blasting treatment so that the surface has a center line average roughness Ra of about 0.2 to 3 μm. Irregularities may be formed. The bonding layer 15 for bonding the insulating substrate 1 and the heat sink 2 is made of a conductive filler such as copper powder or silver powder and a thermosetting resin such as epoxy resin. With such a configuration, the ground or power supply conductor 6 and the heat sink 2 can be mechanically joined and electrically connected.
Such a bonding layer 15 is formed, for example, by screen-printing a conductive adhesive paste made of a mixture of an uncured thermosetting resin and a conductive filler on the lower surface of the wiring board 1 on which the insulating layer 12 is partially applied. The wiring board 1 and the heat radiating plate 2 are firmly joined by applying a printing method by applying the heat radiating plate 2 and thermally curing the radiating plate 2 while applying pressure from above and below. At this time, since the insulating layer 12 made of a thermosetting resin is partially applied to the lower surface of the ground or power supply conductor layer 6, the insulation layer 12 serves as an anchor and is bonded to the ground or power supply conductor layer 6. The layer 15 is firmly joined. Therefore, according to the wiring board with a heat sink of the present invention, even if heat generated when the semiconductor element 3 mounted on the mounting portion 2a of the heat sink 2 is operated is repeatedly applied, the ground or the power supply conductor layer 6 can be connected. There is no separation between the bonding layer 15 and the ground or power supply conductor layer 6 and the heat sink 2 can be firmly bonded electrically and mechanically, and the semiconductor element 3 to be mounted can be maintained for a long time. It can be operated normally. If the paste for the bonding layer 15 is printed and applied so that the inner edge of the paste is located 0.1 to 1 mm on the outer peripheral side from the opening of the through hole 4a, the wiring board 1 and the heat sink 2 are bonded to each other.
When joining via the wiring 15, it is possible to effectively prevent a part of the thermosetting resin contained in the bonding layer 15 from adhering to the wiring conductor layer 5 along the inner wall of the through hole 4 a, Both can be firmly joined without forming a large gap between the substrate 1 and the heat sink 2. Therefore,
It is preferable that the paste for the bonding layer 15 is printed and applied so that the inner edge thereof is located 0.1 to 1 mm on the outer peripheral side from the opening of the through hole 4a. Further, in the present invention, a projection 2a is formed on the upper surface of the heat radiating plate 2 so as to project corresponding to an exposed portion where the ground or power supply conductor layer 6 is exposed from the insulating layer 12. And that is important. As described above, since the projections 2a are formed on the upper surface of the heat sink 2 corresponding to the exposed portions where the ground or power supply conductor layer 6 is exposed from the insulating layer 12, the wiring board 1 and the heat sink 2 are formed. And the bonding layer 15
The thickness of the bonding layer 15 does not increase at the bonding portion between the ground or the power supply conductor layer 6 and the electric resistance between the ground or the power supply conductor layer 6 and the radiator plate 2 is low. Can be connected. Further, when the wiring board 1 and the heat sink 2 are joined via the joining layer 15, the grounding or power supply conductor layer 6 and the joining layer 15 are sufficiently pressed into contact with the projection 2a. Therefore, the two can be electrically and stably connected to each other without causing any poor adhesion. If the height of the protrusion 2 a formed on the upper surface of the heat sink 2 is smaller than the thickness of the insulating layer 12, the bonding layer 15
Is likely to be thicker between the ground or power supply conductor layer 6 and the protrusion 2a, and the wiring board 1 and the heat sink 2
When bonding is performed via the bonding layer 15, there is a risk that the bonding layer 15 and the grounding or power supply conductor layer 6 will not be sufficiently pressed into contact with each other by the projections 2a, and that a void or poor adhesion will occur between them. It will be big. Therefore, it is preferable that the height of the projection 2a is larger than the thickness of the insulating layer 12. Thus, according to the wiring board with radiator plate of the present invention, the semiconductor element 3 is mounted on the mounting portion 2a of the radiator plate 2, and each electrode of the semiconductor element 3 and the wiring conductor layer 5
Are electrically connected to each other through a bonding wire 13, and thereafter, a sealing resin is potted into the through holes 4a and 7a to perform resin sealing, thereby obtaining a semiconductor device. In such a wiring board with a heat sink, a solder resist layer 16 covering the outer peripheral portion of the external connection conductor 8 may be provided on the wiring board 1 if necessary. Such a solder resist layer 16 is made of a thermosetting resin such as an epoxy resin containing an insulating filler such as silica, and is used when attaching the external connection member 14 such as a solder ball on the external connection conductor 8. Acts as a dam for controlling unnecessary spreading of the external connection member 14. Such a solder resist layer 16 is formed by applying an uncured photosensitive thermosetting resin paste to the upper surface of the insulating plate 7 on which the external connection conductors 8 are formed by using a screen printing method, and using a conventionally known photo resist. After etching into a predetermined pattern by lithography, it can be formed by thermosetting. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the wiring board 1 to which the two insulating plates 5 and 7 are bonded is described.
However, a wiring board formed by integrally forming a wiring conductor layer and an external connection conductor on the upper surface of one insulating plate and forming a ground or power supply conductor layer on the lower surface, Using a wiring board formed by laminating the above insulating plates. According to the wiring board with a heat sink of the present invention,
Since the insulating layer made of a thermosetting resin is partially adhered to the lower surface of the ground or power supply conductor layer, the insulation layer and the bonding layer are firmly joined, and the ground or power supply conductor layer is adhered. The heat sink is firmly joined to the lower surface of the insulating substrate. In addition, since the projecting portion is provided on the upper surface of the heat sink corresponding to the exposed portion of the grounding or power supply conductor layer, the thickness of the joining layer does not increase at the portion where the grounding or power supply conductor layer is joined, Therefore, the ground or power supply conductor layer and the heat sink can be connected with a low electric resistance via the bonding layer. Further, when the wiring board and the heat sink are joined via the joining layer, the grounding or the power supply conductor layer and the joining layer are sufficiently pressed against each other by the projection, so that a void or poor adhesion occurs between the two. Therefore, both can be connected electrically and satisfactorily and stably.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an example of an embodiment of a wiring board with a heat sink according to the present invention. FIG. 2 is a cross-sectional view of a conventional wiring board with a heat sink. [Description of Signs] 1 ... Insulating substrate 2 ... Heat radiation plate 2a ... Protrusion 3 ... Semiconductor element 4a ... Through hole 5 for housing semiconductor element ... Wiring conductor layer 6... Grounding or power supply conductor layer 12... Insulating layer 15.

Claims (1)

Claims: 1. An insulating substrate having a through hole for accommodating a semiconductor element in a central portion, a wiring conductor layer applied from an upper surface around the through hole to an outer peripheral portion of the insulating substrate, A ground or power supply conductor layer applied to the lower surface of the insulating substrate, and a thermoset partially applied to the lower surface of the ground or power supply layer so as to expose a part of the ground or power supply conductor layer Bonded to the insulating layer made of a conductive resin, the exposed portion of the ground or power supply conductor layer, and the insulating layer via a bonding layer made of a conductive filler and a thermosetting resin so as to cover the through hole. A wiring board with a radiating plate, comprising: a radiating plate having a projection formed on an upper surface of the radiating plate so as to correspond to the exposed portion. substrate.