JP6965004B2 - Printed wiring board and its manufacturing method - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is a printed wiring board and its manufacture, in which heat generated from an electronic component is transferred to a heat radiating body arranged on the surface side facing the electronic component mounting surface by a metal piece arranged directly under the electronic component. It's about the method.

As a means to efficiently dissipate heat generated from electronic components (for example, surface mount electronic components such as "FETs" and "MOSFETs" that generate a large amount of heat) to the outside, directly under the electronic components mounted on the printed wiring board. Conventionally, a means of providing a plurality of thermal vias composed of through-holes through holes and dissipating heat to the outside via a radiator (radiation pattern or heat sink) arranged on the back surface side of the printed wiring board has been generally used. I came.

However, due to the progress of higher functionality and higher performance of equipment, the amount of heat generated from electronic components has increased to an extent that is incomparable to conventional ones. It has become impossible to cut off (that is, it has become impossible to dissipate heat enough to operate electronic components normally).
Therefore, in recent years, a means of embedding a metal piece having a large heat capacity (for example, "copper piece") instead of the thermal via has been studied and reported (see, for example, Patent Document 1).

An example of a printed wiring board having a configuration in which the above-mentioned "metal piece" is embedded will be described with reference to a schematic cross-sectional view of the printed circuit board Pc shown in FIG. 7.
The terms "printed wiring board" and "printed circuit board" appear in the text (including text explaining the configuration of the present invention), but for convenience of explanation, before mounting and arranging the electronic components and the radiator. The ones are referred to as "printed wiring boards", and the ones after mounting and arranging them are referred to as "printed circuit boards".
Further, in the description of accommodating a metal piece in the metal piece accommodating hole, the terms "electronic component mounting surface side opening end" and "radiator placement surface side opening end" appear, but the "opening end" here. Does not mean only the opening end of the "metal piece accommodating hole" provided in the "insulating substrate", but is provided so as to surround the "metal piece accommodating hole opening end", for example, FIG. When the "outer layer wiring patterns 3a and 3b" and the "solder resist 7" shown in FIG. 7 are present between the "electronic component 11 and the radiator 14" and the open end of the "metal piece accommodating hole 8". Means the open end formed by the "outer layer wiring patterns 3a and 3b" and the "solder resist 7". In FIG. 6, reference numeral 10 indicates an adhesive, 8A indicates the position of the opening end on the electronic component mounting surface side, and 8B indicates the position of the opening end on the radiator arrangement surface side.

In FIG. 7, the printed circuit board Pc is at least an insulating substrate 1, an electronic component 11 mounted on one surface of the insulating substrate 1, and a radiator (heat sink) arranged on the other surface of the insulating substrate 1. Etc.) 14, a metal piece accommodating hole 8 penetrating the insulating substrate 1, and an electronic component 11 arranged in the metal piece accommodating hole 8 and via a solder 13 on the exposed surface 99A side of the electronic component connection side. A metal piece 99 that is connected and is connected to the heat radiating body 14 via a heat conductive adhesive (heat conductive and insulating grease, sheet, etc.) 15 on the exposed surface 99B side of the heat radiating body, and the said metal piece 99. The electronic component mounting side surface A of the insulating substrate 1 includes a solder resist 7 formed so as to surround the metal piece accommodating hole 8. Reference numeral 12 shown in the drawing is a terminal drawn from the electronic component 11, and is connected to the mounting pad 3c provided on the printed wiring board Pw via solder.

As the metal piece 99 arranged in the metal piece accommodating hole 8, a metal piece 99a provided with a recess 99a on the exposed surface 99A side on the electronic component connection side to prevent solder from flowing out during the soldering process is used. The surface opposite to the concave portion 99a, that is, the surface on the convex portion 99b side (exposed surface 99B on the radiator connection side), is the radiator arrangement side surface B (the surface on the side where the radiator 14 is arranged) of the insulating substrate 1. It is arranged so as to be in the same plane as.

By the way, the most important thing to pay attention to in manufacturing the printed wiring board used for this kind of printed circuit board is the protrusion of the metal piece arranged in the metal piece accommodating hole in the Z-axis direction.
For example, to explain using the configuration of FIG. 7, when the exposed surface 99A on the electronic component connection side protrudes from the solder resist 7 formed so as to surround the metal piece accommodating hole 8, the electronic component concerned. If there is a concern that mounting failure of No. 11 may occur, and if the exposed surface 99B on the radiator connection side protrudes from the lower surface (dissipator arrangement side surface B) of the insulating substrate 1, the metal piece 99 and the metallic piece 99B This is because there is a concern that the insulation reliability between the metal piece 99 and the heat radiating body 14 cannot be ensured because the distance from the heat radiating body 14 becomes narrow and the heat conductive adhesive 15 having insulating properties becomes thin. be.

Therefore, normally, in consideration of the dimensional error of the metal piece or the insulating substrate (printed wiring board), the opening ends located above and below the metal piece accommodating hole (in the configuration of FIG. 7, the electronic component mounting side surface A) , Corresponds to the outer surface of the solder resist 7 formed so as to surround the metal piece accommodating hole 8, and corresponds to the lower surface of the insulating substrate 1 on the radiator arrangement side surface B). The metal pieces (dimensions that surely fit within the positions of the opening ends located above and below the metal piece accommodating hole 8) are arranged.

However, the printed wiring board Pw shown in FIG. 7 has the following problems in practice.
That is, also in the printed wiring board Pw shown in FIG. 7, the length between the opening ends located above and below the metal piece accommodating hole 8 (position 8A of the opening end on the electronic component mounting surface side and the opening end on the radiator arrangement surface side). The metal piece 99 having a dimension shorter than the position 8B) is arranged. However, as a method of arranging the metal piece 99, the exposed surface 99B on the radiator connection side and the radiator of the insulating substrate 1 are arranged. Since the side surface B is arranged so as to be in the same plane, when the large warped portion shown in FIG. 8 is generated on the insulating substrate 1 (printed wiring board Pw), the radiator connecting side of the metal piece 99 There is a risk that the exposed surface 99B protrudes from the position 8B of the opening end on the radiator placement surface side of the metal piece accommodating hole 8 and the insulation reliability with the radiator 14 as described above cannot be ensured. The problem is that there is.

As a means for avoiding such a danger, when the metal piece 99 is arranged in the metal piece accommodating hole 8, the exposed surface 99B on the radiator connection side of the metal piece 99 affects the insulation reliability and the heat dissipation performance. It is conceivable to arrange the radiator so that it is recessed toward the position 8A side of the opening end on the electronic component mounting surface side from the position 8B of the opening end on the surface side where the radiator is arranged. Since it is necessary to prepare a jig or the like having a protrusion corresponding to the hole diameter (it is necessary to prepare each time the specifications are changed), the actual situation is that cost and labor are required.

By the way, regarding the exposed surface 99A side of the electronic component connection side of the metal piece 99, since it is possible to deal with a certain amount of dimensional error with fluid solder, if the amount of dent is set to be slightly larger, There is no particular problem.

Further, in the printed wiring board Pw shown in Patent Document 1, it is also mentioned as one of the concerns that the "press-fitting method" is adopted as the method of arranging the metal pieces 99.
That is, in the "press-fitting method", the metal piece 99 having a diameter smaller than the hole diameter of the metal piece accommodating hole 8 and longer than the dimension in the Z-axis direction of the metal piece accommodating hole 8 is plastically deformed (deformed by pressure). As a result, the metal piece 99 is fixed in the metal piece accommodating hole 8 (that is, the inner wall of the metal piece accommodating hole 8 is fixed by a force that expands in the XY directions), so that the insulating substrate 1 is cracked. Because there are concerns.

Japanese Patent No. 5885630

The present invention has been made in view of the above-mentioned conventional problems and actual conditions, and the exposed surface of the metal piece on the radiator connection side of the metal piece has insulation reliability and insulation reliability without using a special jig having a protrusion. The metal piece is arranged so that the position of the metal piece accommodating hole is recessed toward the position side of the opening end on the electronic component mounting surface side rather than the position of the opening end on the radiator arrangement surface side of the metal piece accommodating hole within a range that does not affect the heat dissipation performance. Furthermore, a printed wiring board that does not cause cracks in the insulating substrate when the metal piece is inserted and a lint wiring board having such excellent insulation reliability and heat dissipation performance can be easily provided at low cost. An object of the present invention is to provide a obtained production method.

As a result of conducting various studies to solve the above problems, the present invention has found that extremely good results can be obtained by using a metal piece with a heat conductive resin and fixing the metal piece with an adhesive. The present invention has been completed.

Further, according to the present invention, the heat generated from an electronic component is transferred to a radiator arranged on the side opposite to the side surface on which the electronic component is mounted by a metal piece arranged directly under the electronic component. In the manufacturing method, at least in the step of forming the metal piece accommodating hole in the insulating substrate and when the metal piece is arranged in the metal piece accommodating hole, the exposed surface of the metal piece on the electronic component connection side is the electron of the metal piece accommodating hole. The position is below the position of the opening end on the component mounting surface side, and the exposed surface on the radiator connection side of the metal piece is the opening end on the electronic component mounting surface side rather than the position of the opening end on the radiator placement surface side of the metal piece accommodating hole. On the exposed surface on the radiator connecting side of the metal piece having a length that is recessed on the position side of, between the exposed surface on the connecting side of the radiator and the position of the opening end on the radiator placement surface side of the metal piece accommodating hole. A step of forming a thermally conductive resin having a thickness corresponding to a distance, a step of inserting the metal piece with the thermally conductive resin into the metal piece accommodating hole, and an adhesive in the gap between the metal piece accommodating hole and the metal piece. The above problem is solved by a method for manufacturing a printed wiring board, which comprises a step of supplying the metal piece and fixing the metal piece in the metal piece accommodating hole.

According to the present invention, as a metal piece to be arranged in the metal piece accommodating hole, a metal piece with a heat conductive resin in which a heat conductive resin having a desired thickness is formed in advance on the exposed surface of the metal piece on the radiator connection side. Therefore, a printed wiring board having excellent heat dissipation performance and insulation reliability can be easily obtained at low cost.
Furthermore, as a method of fixing the metal piece, an adhesive is poured into the gap formed between the inner wall of the metal piece accommodating hole and the metal piece, so that the crack problem that has been a problem in the press-fitting method is also solved. It can be eliminated.

Schematic cross-sectional view of a printed circuit board using the printed wiring board of the present invention. (A) to (c) are schematic cross-sectional process diagrams showing a manufacturing example of the printed wiring board of the present invention. (D) to (f) are schematic cross-sectional process diagrams following FIG. FIG. 6A is a schematic cross-sectional view showing a manufacturing example of a metal piece in which a heat conductive resin is formed on an exposed surface on the connecting side of a radiator. In (a), a heat conductive resin and a protective film are sequentially laminated on one surface of a metal plate. The state is shown, and (b) shows the state in which the thing of (a) is punched into individual pieces of metal (with a heat conductive resin). The schematic plan view which shows the fixed state of the metal piece in the printed wiring board of this invention. The schematic cross-sectional view which shows the position of the opening end of the metal piece accommodating hole in the printed wiring board of this invention. Schematic cross-sectional view of a conventional printed circuit board. FIG. 6 is a schematic cross-sectional view of a main part showing an example in which a metal piece protrudes from the lower surface of an insulating substrate in a conventional printed wiring board.

Hereinafter, embodiments of the printed wiring board of the present invention will be described with reference to FIG. For convenience of explanation, the one before the metal piece (with the heat conductive resin) is accommodated in the metal piece accommodating hole is referred to as an "insulated substrate", and the one after the accommodating is referred to as a "printed wiring board". Go.

In FIG. 1, the PW is a printed wiring board, and the insulating substrate 1 includes a three-layer core insulating layer 100, an inner layer wiring pattern 2 formed on the boundary surface and the front and back surfaces of the three-layer core insulating layer 100, and the like. A core substrate 1a composed of a belled hole 4 for connecting the inner layer wiring patterns 2 formed on each surface of the three core insulating layers 100 in the vertical direction and one layer on each of the front and back surfaces of the core substrate 1a are laminated. A build-up layer 1b composed of an outer layer wiring pattern 3a and 3b and a mounting pad 3c formed on the outer layer side of the interlayer insulating layer 101 and the interlayer insulating layer 101, and the front and back surfaces of the core substrate 1a and the core substrate 1a. Through plating through hole that penetrates the build-up layer 1b laminated on the board and connects the core substrate 1a and the inner layer wiring pattern 2 and the outer layer wiring patterns 3a and 3b formed on the build-up layer 1b in the vertical direction. A blind via hole 6 connecting the outer layer wiring pattern 3b and the inner layer wiring pattern 2 adjacent to the outer layer wiring pattern 3b, the front and back surfaces of the three-layer core insulating layer 100 and the three-layer core insulating layer 100. A solder resist 7 that penetrates the interlayer insulating layer 101 laminated on the board and protects the metal piece accommodating hole 8 formed at a position directly below the electronic component 11 and the outer layer wiring patterns 3a and 3b. It is composed of and.

In such an insulating substrate 1, 9 is a metal piece, and the exposed surface 9A on the electronic component connecting side is a position 8A or less at the position 8A or less of the opening end on the electronic component mounting surface side of the metal piece accommodating hole 8, more specifically, the electronic component. It is located at the same position as or below the outer surface of the outer layer wiring pattern 3a of the mounting side surface A, and the exposed surface 9B on the radiator connection side is located at the position 8B of the opening end on the radiator arrangement surface side of the metal piece accommodating hole 8. With the metal piece accommodating hole 8 in a recessed position, more specifically, in a state of being recessed toward the position 8A of the opening end on the electronic component mounting surface side with respect to the outer surface of the interlayer insulating layer 101 of the radiator arrangement side surface B. A printed wiring board PW is configured by being arranged and fixed in the metal piece accommodating hole 8 via an adhesive 10 supplied to a gap between the metal piece 9 and the metal piece 9.
In the present invention, as the metal piece 9, the heat conductive resin 15a that has been cured in advance is placed on the exposed surface 9B on the connecting side of the radiator, and the heat radiating body of the exposed surface 9B on the connecting side of the radiator and the metal piece accommodating hole 8. Since the metal piece 500 with a heat conductive resin formed with a thickness corresponding to the distance from the position 8B of the opening end on the arrangement surface side is used, when the metal piece 9 is fixed to the arrangement position, the metal piece 9 is fixed. It is not necessary to prepare a dedicated jig (a jig having a protrusion corresponding to the amount of dent from the position 8B of the opening end on the side of the radiator arrangement surface and the hole diameter of the metal piece accommodating hole 8), and the insulating substrate 1 ( Even when a large warp occurs in the printed wiring board PW), the insulation reliability between the metal piece 9 and the radiator 14 can be ensured.

Further, the electronic component 11 is mounted on one surface of the printed wiring board PW via the solder 13, and the radiator 14 is arranged on the other surface via the heat conductive adhesive 15 to form a printed circuit board. The PC is configured. In FIG. 1, reference numeral 12 is a terminal drawn from the electronic component 11 and is connected to the mounting pad 3c via solder.

Subsequently, the manufacturing method of the printed wiring board PW will be described with reference to FIGS. 2 and 3.

First, an inner layer wiring pattern 2 is formed on the boundary surface and the front and back surfaces of the three core insulating layers 100 (100a, 100b) by a well-known method, and the inner layer wiring patterns 2 formed on each surface are connected in the vertical direction. By forming the belly hole 4 to be formed, the core substrate 1a is obtained.
Then, by laminating the build-up layer 1b composed of the interlayer insulating layer 101 and the metal foil 102 on the front and back surfaces of the core substrate 1a, an intermediate substrate having a six-layer structure shown in FIG. 2A is obtained.

As the core insulating layers 100a and 100b, those in which reinforcing fibers such as glass cloth, which are generally used as materials, are impregnated with a thermosetting resin such as epoxy resin can be used, and a double-sided plate arranged in the center can be used. Since a certain thickness is required (strength enough to flow through the production line) due to the initial formation, the core insulating layer 100a arranged in the center is 500 to 700 μm, and the core insulating layers 100b arranged above and below this are required. 200-300 μm.

A general copper foil can also be used for the metal foil for forming the inner layer wiring pattern 2, and the thickness thereof is 50 to 100 μm on the core insulating layer 100a arranged in the center, and is arranged above and below the core insulating layer 100a. A core insulating layer 100b having a thickness of 18 to 35 μm is used.

As a method for forming the belled hole 4, a through hole having a cutting diameter of φ0.25 to 0.35 mm is drilled by drilling or the like, and after desmear treatment, a plating thickness of 25 μm is set for the through hole. It can be formed by performing a plating process (for example, "copper plating process").

As the interlayer insulating layer 101 and the metal foil 102, the same ones used for the core substrate 1a can be used, and the thickness thereof is, for example, 60 to 100 μm for the interlayer insulating layer 101 and 9 to 18 μm for the metal foil 102.

Subsequently, as shown in FIG. 2B, the planned formation portion of the blind via hole 6 is irradiated with a laser (for example, “carbon dioxide laser”), and the cutting diameter on the top side is φ0.15-0.25 mm. The non-through hole 6a is drilled, and the through hole 5a having a cut diameter of φ0.25 to 0.35 mm is drilled by drilling the planned formation portion of the through-plating through hole 5.
When the through hole 5a is drilled with a drill, for example, the metal piece accommodating hole 8 having a cutting diameter of φ3.5 to 4.5 mm is also drilled.

Next, after cleaning the insides of the through holes 5a, the non-through holes 6a, and the metal piece accommodating holes 8 by desmear treatment, electrolytic plating treatment using a plating bath for via filling and electrolytic plating treatment using a high-slow bath. By sequentially performing, plating 103 (for example, “copper plating” having a thickness of 25 μm) is deposited on the entire intermediate substrate including the inside of each hole (see FIG. 2C), and then by a well-known photoetching process. After forming the outer layer wiring patterns 3a and 3b and the mounting pad 3c, the solder resist 7 that protects the outer layer wiring patterns 3a and 3b is appropriately formed to obtain the insulating substrate 1 shown in FIG. 3D.

Subsequently, a metal piece 9 with a heat conductive resin 15a (hereinafter, this will be referred to as a “metal piece 500 with a heat conductive resin”) to be arranged in the metal piece accommodating hole 8 is prepared.
The heat conductive resin 15a has an insulating property like the heat conductive adhesive 15 used when arranging the heat radiating body 14, and both terms are described separately for convenience of explanation. However, it can be considered that basically the same material is used.

As a method of preparing the metal piece 500 with a heat conductive resin, first, as shown in FIG. 4A, one surface of the metal plate 200 (for example, "copper plate") is cured with heat conductivity. A resin 15a and a protective film 300 for protecting the resin 15a are sequentially laminated, and then the punching area 400 is punched out by a means such as a general mold press or a die stamp.
After that, if the punched-out protective film 300 is peeled off, the "metal piece 500 with a heat conductive resin" as shown in FIG. 4 (b) can be obtained.

The thickness of the cured heat conductive resin 15a laminated on one surface of the metal plate 200 is such that when the individualized metal piece 500 with the heat conductive resin is arranged in the metal piece accommodating hole 8. The thickness corresponding to the distance between the exposed surface 9B of the metal piece 9 on the radiator connection side and the position 8B of the opening end on the radiator arrangement surface side of the metal piece accommodating hole 8 is set to be, for example, 100 to 200 μm ( See FIG. 3 (d)).

Next, it is a step of arranging the "metal piece 500 with a heat conductive resin" in the metal piece accommodating hole 8, but in the present invention, it is necessary to satisfy the following conditions.
That is, when the metal piece 9 is arranged in the metal piece accommodating hole 8, the exposed surface 9A on the electronic component connection side of the metal piece 9 is located at the position 8A or less of the opening end on the electronic component mounting surface side, more specifically, the electronic component mounting side surface A. The position where the exposed surface 9B on the radiator connection side of the metal piece 9 is recessed from the position 8B of the opening end on the radiator arrangement surface side while being on the same surface as or below the outer surface of the outer layer wiring pattern 3a. More specifically, it is a condition that the position is recessed toward the position 8A side of the opening end on the electronic component mounting surface side from the outer surface of the interlayer insulating layer 101 on the radiator arrangement side surface B.
The position of the exposed surface 9A on the electronic component connection side when the metal piece 9 is arranged in the metal piece accommodating hole 8 can be supplemented by a fluid solder, so that there is not much problem even if there is some dimensional error. However, it is desirable that the depth is within a range that does not affect the solder connectivity with the electronic component 11, for example, the depth is 0 to 400 μm from the position 8A of the opening end on the electronic component mounting surface side. Regarding the position of the exposed surface 9B on the radiator connection side, at least the position of the opening end on the electronic component mounting surface side from the position 8B on the side of the opening on the side where the radiator is arranged in order to ensure the insulation with the radiator. A position recessed by 100 μm on the 8A side is desirable, and on the other hand, from the viewpoint of heat dissipation, the depth within a range in which the desired heat dissipation can be secured, for example, the depth from the position 8B of the open end on the heat dissipation body arrangement surface side is 200 μm. It is desirable to keep it below. In other words, it is desirable that the depth is 100 to 200 μm from the position 8B of the open end on the heat radiating surface side.

In order to dispose the metal piece 9 at the above position, the jig 17 is placed on the surface of the heat dissipator arrangement side surface B of the insulating substrate 1 so as to close the opening end 8B on the radiator arrangement surface side of the metal piece accommodating hole 8. The metal piece 500 with a heat conductive resin is inserted into the metal piece accommodating hole 8 (see FIG. 3D) using a chip mounter or the like, and then the inner wall of the metal piece accommodating hole 8 and heat are generated. The gap 16 formed between the metal piece 500 with the conductive resin (for example, assuming that the metal piece 500 with the thermal conductive resin is arranged in the center of the metal piece accommodating hole 8, the size that can be formed is 50 to 50 on one side. The adhesive 10 is supplied to (about 80 μm), and the metal piece 500 with the heat conductive resin is fixedly arranged in the metal piece accommodating hole 8 (see FIG. 3 (e) and FIG. 5), and then the insulating substrate 1 By removing the jig 17 arranged on the heat radiating body arrangement side surface B, the printed wiring board PW of the present invention shown in FIG. 3 (f) is obtained.

The most notable point in the present invention is that the metal piece 9 to be arranged in the metal piece accommodating hole 8 is previously provided on the radiator connecting side exposed surface 9B, and the radiator connecting side exposed surface 9B and the metal piece accommodating hole 8. A heat conductive resin 15a having a thickness corresponding to the distance from the position 8B of the opening end on the surface side of the heat radiating body is formed (corresponding to "metal piece 500 with heat conductive resin" in the text). It is at the point where it was done.

As a result, the metal piece 9 is arranged at a desired position in the metal piece accommodating hole 8 without using a dedicated jig (a jig having a protrusion) (the position of the exposed surface 9B on the radiator connection side is the heat dissipation performance. As long as the insulation reliability is not affected, the position can be recessed toward the position side of the opening end on the electronic component mounting surface side from the position 8B of the opening end on the side of the radiator arrangement surface).
Further, even when a large warp occurs in the insulating substrate 1, there is no concern that the exposed surface 9B on the radiator connecting side of the metal piece 9 protrudes from the position 8B of the opening end on the side where the radiator is arranged, so that the thermal conductivity is increased. Insulation reliability with the heat radiating body 14 arranged via the adhesive 15 can be reliably ensured (see the enlarged view of the main part shown in FIG. 1).

Further, as a method of fixing the metal piece 500 with the heat conductive resin, a means of supplying the adhesive 10 to the gap 16 formed between the inner wall of the metal piece accommodating hole 8 and the metal piece 9 is also adopted. It is mentioned as one of the features of the invention.
As a result, it is possible to eliminate the concern that the insulating substrate 1 is cracked, which is seen in the press-fitting method.

In explaining the present invention, an example in which the adhesive 10 for fixing the metal piece 500 with the heat conductive resin is supplied to two places of the gap 16 (the schematic plane around the exposed surface 9A on the electronic component connection side of the metal piece 9). Although it has been described with reference to FIG. 5 in which the figure is shown), if the adhesive can be fixed to the radiator arrangement side surface B of the insulating substrate 1 without flowing out, even if the adhesive is supplied to more places (including the entire circumference). There is no particular problem.

Further, as an example of the metal piece accommodating hole 8, the configuration in which the plating 103 is not formed on the inner wall has been described, but it is of course possible to form the plating 103.
However, if the thickness of the plating 103 varies widely, the metal piece 500 with the heat conductive resin may get caught in the protruding portion of the plating 103 when the metal piece 500 with the heat conductive resin is inserted, and an insertion error may occur. Therefore, it can be said that it is desirable to have a configuration in which the plating 103 is not formed.

In explaining the present invention, the present invention has been described using a build-up multilayer printed wiring board having a so-called 1-4-1 structure in which build-up layers are laminated one by one on the front and back surfaces of a four-layer core substrate. Can, of course, be used for double-sided printed wiring boards and multi-layer printed wiring boards with other configurations.

1: Insulated substrate 1a: Core substrate 1b: Build-up layer 2: Inner layer wiring pattern 3a, 3b: Outer layer wiring pattern 3c: Mounting pad 4: Bellowed hole 5: Through plating through hole 5a: Through hole 6: Blind via hole 6a : Non-through hole 7: Solder resist 8: Metal piece accommodating hole 8A: Electronic component mounting surface side opening end position 8B: Dissipator placement surface side opening end position 9, 99: Metal piece 9A, 99A: Electronic component connecting side Exposed surfaces 9B, 99B: Exposed surface 99a on the connecting side of the radiator: Concave 99b: Convex 10: Adhesive 11: Electronic component 12: Terminal 13: Solder 14: Dissipator 15: Thermal conductive adhesive 15a: Thermal conductive resin 16: Gap 17: Jigs 100, 100a, 100b: Core insulating layer 101: Interlayer insulating layer 102: Metal foil 103: Plating 200: Metal plate 300: Protective film 400: Punching area 500: Metal piece A with heat conductive resin : Electronic component mounting side surface B: Heat radiator placement side surface PW, Pw: Printed wiring board PC, Pc: Printed circuit board

Claims (2)

A method for manufacturing a printed wiring board in which heat generated from an electronic component is transferred to a radiator arranged on the side opposite to the side surface on which the electronic component is mounted by a metal piece arranged directly under the electronic component. At least, in the step of forming the metal piece accommodating hole in the insulating substrate and when the metal piece is arranged in the metal piece accommodating hole, the exposed surface of the metal piece on the electronic component connection side is the opening end of the metal piece accommodating hole on the electronic component mounting surface side. The exposed surface of the metal piece on the radiator connection side is recessed toward the position of the opening end on the electronic component mounting surface side rather than the position of the opening end on the radiator arrangement surface side of the metal piece accommodating hole. The exposed surface on the radiator connection side of the metal piece having the length to be the position has a thickness corresponding to the distance between the exposed surface on the radiator connection side and the position of the opening end on the radiator arrangement surface side of the metal piece accommodating hole. The step of forming the heat conductive resin, the step of inserting the metal piece with the heat conductive resin into the metal piece accommodating hole, and the step of supplying an adhesive to the gap between the metal piece accommodating hole and the metal piece to obtain the said A method for manufacturing a printed wiring board, which comprises a step of fixing a metal piece in a metal piece accommodating hole. The position below the position of the opening end on the electronic component mounting surface side of the metal piece accommodating hole is the depth within the range that does not affect the solder connectivity with the electronic component, and the radiator placement surface of the metal piece accommodating hole. The printed wiring board according to claim 1 , wherein a position recessed from the position of the side opening end is a depth within a range in which insulation with the radiator and desired heat dissipation can be ensured. Production method.

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