JP2004056144A - Printed wiring board - Google Patents

Abstract

A printed circuit board capable of controlling electromagnetic noise generated from a built-in electronic component without deteriorating high-frequency characteristics of a high-frequency signal.
A signal transmission wiring is provided in an electric insulating layer. The auxiliary wiring 104 is provided on the electrical insulating layer 103 in an electrically insulated state from the signal transmission wiring 105. At least a part of the auxiliary wiring 104 is covered with the electromagnetic shielding layer 106. This suppresses radiation noise from inside or outside the printed wiring board without deteriorating the characteristics of the signal transmitted through the signal transmission wiring 105.
[Selection diagram] Fig. 1

Description

The present invention relates to a printed wiring board used for an electronic device such as an information processing device and a wireless communication device, and more particularly, to a printed wiring board having a multilayer substrate structure incorporating electronic components such as transistors and integrated circuits. In particular, the present invention relates to a printed wiring board that requires control of electromagnetic noise generated from built-in electronic components in order to suppress interference between electronic components, and a method of manufacturing the same.

In recent years, for printed wiring boards, multilayer printed wiring boards with built-in electronic components have been proposed in order to meet the demand for further miniaturization. In a multilayer printed wiring board having a built-in electronic component, for example, a sheet that exhibits flexibility by mixing an insulating material with fused silica and an epoxy resin is used. This sheet is arranged in multiple layers, and electronic components such as transistors and integrated circuits are built in between the layers to form a multilayer printed wiring board.

電子 Electronic components such as transistors and integrated circuits generate electromagnetic noise. Therefore, when electronic components are embedded in a printed wiring board, electromagnetic noise generated inside the printed circuit board causes malfunctions of electronic devices (including built-in electronic components) near the printed wiring board and degrades the high-frequency characteristics of the electronic devices. Causes the problem of causing

Particularly, in a printed wiring board in which miniaturization (including thinning) is promoted, signal transmission wiring in a wiring layer becomes denser. As a result, mutual interference between the signal transmission wirings increases, and deterioration of high-frequency characteristics or malfunction of electronic components is more likely to occur.

多層 In addition, in a multilayer printed wiring board having a built-in electronic component, there is a problem that the influence of unnecessary radiation emitted from the built-in electronic component affects other built-in electronic components and causes a malfunction.

構成 As a configuration for solving such a problem, there is a conventional printed wiring board shown in FIG. This printed wiring board 801 includes laminated electric insulating layers 803, 803, signal transmission wiring 805, ground wiring 804, and wiring 805, 804 formed of copper or the like on both sides and inside of electric insulating layers 803, 803. And an electromagnetic shielding layer 806.

The electromagnetic shielding layer 806 is provided on the surface of the signal transmission wiring 805 located inside the electric insulating layer 803. The electromagnetic shielding layer 806 is made of a magnetic material having a magnetic loss such as ferrite, and is applied on the signal transmission wiring 805. Unwanted radiation from the signal transmission wiring 805 is attenuated by the electromagnetic shielding layer 806.
(For example, see Patent Document 1)
JP-A-9-283939

However, in such a configuration, the desired signal is attenuated at the same time as the radiation noise is reduced, and as a result, the high-frequency characteristics are deteriorated.

In order to solve the above-described problem, a printed wiring board of the present invention is provided between an insulating plate including a plurality of stacked electrical insulating layers, an electronic component built in the insulating plate, and the electrical insulating layer. The signal transmission wiring provided has an auxiliary wiring provided on the insulating plate in an electrically insulated state from the signal transmission wiring, and an electromagnetic shielding layer covering at least a part of the auxiliary wiring. This makes it possible to suppress radiation noise from inside or outside the printed wiring board without deteriorating the high-frequency characteristics of the high-frequency signal.

(4) In order to effectively prevent radiation noise on electronic components, it is effective to provide an electromagnetic shielding layer near the electronic components. The electromagnetic shielding layer can be provided on the auxiliary wiring or the signal transmission wiring, but it is difficult to provide the electromagnetic shielding layer on the signal transmission wiring for the following reasons.

The signal transmission wiring cannot be arranged in a certain area of the electric insulating layer centering on the area where the electronic components are arranged. This is because when signal transmission wiring is placed in or near the area where electronic components are built in, the signal transmission wiring is physically distorted due to the deformation of the electrical insulation layer caused by the built-in electronic components, resulting in poor signal transmission characteristics. This is to cause an adverse effect. Therefore, signal transmission wiring cannot be provided on the electronic component disposition area or on the surface of the electrical insulating layer in the vicinity thereof. In this case, the electromagnetic shielding layer must be disposed as close to the electronic component built-in area as possible. Becomes impossible. Conversely, if the signal transmission wiring is separated from the electronic component to a position where the deformation of the electric insulating layer due to the built-in electronic component can be stopped, the electromagnetic shielding layer can be provided without adversely affecting the signal transmission characteristics. The area required for wiring installation becomes large, which hinders high-density mounting.

On the other hand, the auxiliary wiring installed in the present invention is a wiring that does not transmit a signal and does not affect the electrical characteristics of the printed wiring board. Therefore, high precision is not required for the shape of the auxiliary wiring, and even if physical distortion is given to the auxiliary wiring by providing the auxiliary wiring on the electronic component disposition area or the surface of the electric insulating layer in the vicinity thereof, there is a particular problem. Not be. Therefore, the electromagnetic shielding layer can be provided on the auxiliary wiring provided on the surface of the electric insulating layer at or near the electronic component arrangement region. For this reason, in the configuration of the present invention in which the auxiliary wiring is provided and the electromagnetic shielding layer is provided on the auxiliary wiring, it is possible to maintain high-density mounting and suppress radiation noise to the electronic component.

The electromagnetic shielding layer is preferably made of a magnetic material having a magnetic loss, so that radiation noise can be suppressed efficiently.

In the present invention, it is preferable that the auxiliary wiring is connected to a ground potential. This makes it possible to realize a ground wiring exhibiting the same electrical characteristics with a smaller occupation area as compared with a configuration of only the auxiliary wiring connected to the ground potential. Therefore, the printed wiring board can be further reduced in size. In addition, by adopting the configuration of the present invention, there is a concern that the electronic component may be embedded in the printed wiring board because of the fear of spreading the adverse influence (unnecessary radiation and the like) to the surroundings and, on the contrary, the fear of spreading the bad influence from the surroundings. Can be built into the printed wiring board without hesitation. As a result, the types of electronic components that can be built into the printed wiring board increase, and the degree of freedom in designing the printed wiring board increases accordingly.

However, according to the present invention, even in a configuration in which the auxiliary wiring is not connected to the ground potential, a radiation noise suppression effect substantially equal to the configuration in which the electromagnetic shielding layer is connected to the ground potential can be obtained. Further, in this case, since the auxiliary wiring is not connected to the ground potential, the restriction in designing the wiring pattern is not restricted. Specifically, it is possible to design a wiring pattern of the auxiliary wiring by using a surplus space in various wirings.

は In the present invention, it is preferable to provide an insulator film between the auxiliary wiring and the electromagnetic shielding layer. Then, the auxiliary wiring and the electromagnetic shielding layer arranged via the insulator film have a function as a decoupling capacitor, and the radiation noise from inside or outside the printed wiring board can be more efficiently suppressed. it can.

In the present invention, it is preferable that the auxiliary wiring is provided between the signal transmission wirings. Then, the mutual interference between the signal transmission wirings is efficiently suppressed.

In the present invention, it is preferable that the auxiliary wiring is provided between the signal transmission wiring and the electronic component or between the electronic components. Then, the mutual interference between the signal transmission wiring and the electronic component and the mutual interference between the electronic components are efficiently suppressed.

In particular, if the auxiliary wiring is provided so as to face the surface of the component having the higher intensity of unnecessary radiation radiated by the electronic component out of both component surfaces of the electronic component, the signal transmission wiring and the electronic component can be efficiently provided. , And mutual interference between electronic components can be suppressed. The component surface having the higher unnecessary radiation intensity includes, for example, a terminal forming surface of an electronic component, but may also be a component surface located on the opposite side of the terminal forming surface. Furthermore, if the auxiliary wiring is provided so as to face each of the terminal forming surface of the electronic component and the component surface located on the opposite side, the above-described mutual interference can be surely suppressed.

In the present invention, it is preferable that the auxiliary wiring is provided around the electronic component. Then, radiation noise from inside and outside of the electronic component is efficiently suppressed.

Preferably, the auxiliary wiring is provided so as to cover an upper surface of the electronic component. Then, radiation noise from inside and outside of the electronic component is efficiently suppressed.

The auxiliary wiring includes a first auxiliary wiring provided to cover one surface of the electronic component, and a second auxiliary wiring provided to surround the electronic component and be provided therearound. It is preferable that a conductor for electrically connecting the auxiliary wiring and the second auxiliary wiring is provided on the electric insulating layer conductor. Then, the radiation noise from inside and outside of the electronic component is more efficiently suppressed. This is for the following reason.

簡易 Since the first and second auxiliary wirings (including the electromagnetic shielding layer) are electrically connected by the conductor, a simple three-dimensional shield is formed for the electronic component. This improves the ability to suppress radiation noise.

In addition, a plurality of the conductors are provided along the width direction of the side surface of the electronic component, and opposing directions of mutually adjacent conductors are non-parallel to the width direction of the side surface of the electronic component, and the opposing directions sequentially intersect. Preferably, the conductor is arranged such that Then, the number of conductors installed along the side surface of the electronic component increases. Further, the conductors are distributed and arranged with regularity. As a result, radiation noise from inside and outside of the electronic component is more efficiently suppressed.

は In the present invention, it is preferable that the electromagnetic shielding layer is provided on both surfaces of the auxiliary wiring. Then, the electromagnetic shielding effect will be further enhanced.

は In the present invention, it is preferable that the electromagnetic shielding layer further covers at least a part of the signal transmission wiring. Then, the electromagnetic shielding effect will be further enhanced.

It is preferable that the electromagnetic shielding layer is provided on both surfaces of the signal transmission wiring. Then, the electromagnetic shielding effect will be further enhanced.

Preferably, an insulator film is provided between the signal transmission wiring and the electromagnetic shielding layer covering the signal transmission wiring. This makes it possible to electrically separate the signal transmission wiring from the electromagnetic shielding layer, thereby improving the high-frequency characteristics of the signal component transmitted through the signal transmission wiring.

Note that the signal transmission wiring is provided on each of both surfaces of the electrical insulating layer, and a conductor connecting the signal transmission wiring on the both surfaces is provided through the electrical insulating layer, and the electrical insulating layer and the It is preferable that the electromagnetic shielding layer is spaced apart from the conductor. Then, as a result that the conductor does not contact the electromagnetic shielding layer, it is possible to prevent physical deterioration of the conductor and deterioration of the high-frequency characteristics of the high-frequency signal transmitted through the conductor.

The electric insulating layer is preferably made of a composite material formed by mixing an epoxy resin and an inorganic filler.

In the present invention, it is preferable that the auxiliary wiring is connected to a ground potential, and the length of the electromagnetic shielding layer is set to １ ／ of the wavelength corresponding to the frequency to be suppressed. Then, the auxiliary wiring having the electromagnetic shielding layer functions as a resonator at the frequency to be suppressed. This makes it possible to efficiently suppress unnecessary radiation at a specific frequency inside the printed wiring board.

In the present invention, it is preferable that the length of the auxiliary wiring is set to a half of the wavelength corresponding to the frequency to be suppressed. Then, the auxiliary wiring having the electromagnetic shielding layer functions as a resonator at the frequency to be suppressed. This makes it possible to efficiently suppress unnecessary radiation at a specific frequency inside the printed wiring board.

The method of manufacturing a printed wiring board according to the present invention includes the steps of preparing a transfer forming material, patterning the auxiliary wiring on the transfer forming material, and patterning an electromagnetic shielding layer on the auxiliary wiring on the transfer forming material. Forming the auxiliary wiring layer and transferring the auxiliary wiring layer from the transfer forming material to the electrical insulating layer by bringing the electromagnetic shielding layer into contact with the electrical insulating layer.

Preferably, the method for manufacturing a printed wiring board of the present invention further includes a step of forming the electromagnetic shielding layer on an outer surface of the auxiliary wiring layer formed on the electrical insulating layer.

The printed wiring board of the present invention can suppress radiation noise inside and outside the printed wiring board without deteriorating the high-frequency characteristics of the high-frequency signal transmitted through the signal transmission wiring.

(4) Since the electromagnetic shielding layer is provided on the auxiliary wiring, electric interference between signal transmission wirings and between electronic components can be suppressed as compared with a configuration in which only the auxiliary wiring is provided.

(4) Since a ground having a high shielding strength can be formed in a small occupation area, the printed wiring board can be further reduced in size. In particular, the range of electrical characteristics of electronic components that can be mounted on a substrate is widened.

(4) Even when the auxiliary wiring is not connected to the ground potential, the same radiation noise suppression effect as that obtained by forming the ground electromagnetic shielding layer can be obtained. In this case, since the auxiliary wiring is not connected to the ground potential, the auxiliary wiring and the like can be formed by using a surplus space generated in the wiring pattern without being restricted by design restrictions.

(4) Radiation noise from inside or outside the printed wiring board can be easily suppressed without changing the size of the printed wiring board.

Since a simple three-dimensional shield can be formed for the built-in electronic components, the radiation noise suppressing ability is further improved.

(4) By arranging and distributing the conductors with regularity, the radiation noise suppressing ability is further improved.

According to the present invention, since the electromagnetic shielding layer can act as a resonator at the frequency to be suppressed, it is possible to suppress unnecessary radiation at a specific frequency inside the printed wiring board.

According to the present invention, since the radio wave shielding layers are formed on both sides of the auxiliary wiring, the radiation noise suppressing ability is further improved.

In addition, the present invention can prevent the conductor from coming into contact with the electromagnetic shielding layer, so that the deterioration of the conductor and the high-frequency characteristics of the high-frequency signal can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)
FIG. 1A is a cross-sectional view of a printed wiring board 101 with a built-in electronic component according to a first embodiment of the present invention. The printed wiring board 101 has an insulating plate 103. The insulating plate 103 has two layers of electric insulating layers 103A and 103B that are laminated and integrated. The electric insulating layers 103A and 103B are made of a composite material in which an epoxy resin and an inorganic filler (such as fused silica or alumina) are mixed. The electric insulating layers 103A and 103B have the inner via 102. The inner via 102 is made of a thermosetting resin or the like containing conductive particles. The inner via 102 is provided so as to penetrate the electric insulating layers 103A and 103B in the thickness direction. The electric insulating layers 103A and 103B have a signal transmission wiring 105 and an auxiliary wiring 104. The signal transmission wiring 105 and the auxiliary wiring 104 are provided on both surfaces of the electric insulating layers 103A and 103B. The signal transmission wiring 105 performs mutual transmission of signals with the outside of the printed wiring board 101. The auxiliary wiring 104 is arranged in a non-contact state with the signal transmission wiring 105, that is, in an electrically insulating state. The auxiliary wiring 104 is connected to the ground potential. The auxiliary wiring 104 functions as a ground wiring (ground). The signal transmission wiring 105 is disposed between both surfaces of the insulating plate 103 and between the electric insulating layers 103A and 103B. The auxiliary wiring 104 is arranged between the electric insulating layers 103A and 103B. The inner via 102 electrically connects the signal transmission wirings 105, 105 and the auxiliary wirings 104, 104 together.

電磁 An electromagnetic shielding layer 106 is provided on the signal transmission wiring 105 and the auxiliary wiring 104. The electromagnetic shielding layer 106 is made of a magnetic material having a magnetic loss. Specifically, the electromagnetic shielding layer 106 is made of a material having a magnetic loss such as ferrite.

The electromagnetic shielding layer 106 is provided between the wirings 105 and 104 and the electric insulating layers 103A and 103B. The electromagnetic shielding layer 106 between the wirings covers the entire surface of the wirings 105 and 104 on the side of the electric insulating layer. Electromagnetic shielding layers 106 provided on the signal transmission wiring 105 and the auxiliary wiring 104 between the electric insulating layers 103A and 103B are provided on both surfaces of the wirings 105 and 104. The electromagnetic shielding layer 106 between the layers also covers the entire surfaces of the signal transmission wiring 105 and the auxiliary wiring 104.

絶 縁 An insulator film 107 is provided between the signal transmission wiring 105 and the electromagnetic shielding layer 106. No insulator film 107 is provided between the electromagnetic shielding layer 106 and the auxiliary wiring 104. This is for the following reason. When the electromagnetic shielding layer 106 is provided on the signal transmission wiring 105, the transmitted signal is attenuated. In the present embodiment, the attenuation is suppressed by providing an insulator film 107 between the signal transmission wiring 105 and the electromagnetic shielding layer 106. On the other hand, in the auxiliary wiring 104, there is no need to provide the insulator film 107 in order not to transmit a signal.

イ ン Inner via insertion holes 108 are formed in the electromagnetic shielding layer 106 and the insulator film 107 provided in the signal transmission wiring 105. The inner via insertion hole 108 is provided at a position where the inner via 102 is formed. The inner via insertion hole 108 has a diameter slightly larger than the diameter of the inner via 102. The inner via 102 is arranged concentrically with the inner via insertion hole 108. As a result, the inner via 102 does not come into contact with the electromagnetic shielding layer 106 and the insulator film 107 but comes into contact only with the signal transmission wiring 105 to be electrically connected. Accordingly, the inner via 102 electrically connects the signal transmission wirings 105 while maintaining high high-frequency characteristics.

(4) No inner via insertion hole 108 is formed in the electromagnetic shielding layer 106 provided in the auxiliary wiring 104. This is because no signal is transmitted to the auxiliary wiring 104. The interlayer connection of the auxiliary wiring 104 is only required to be electrically connected, and particularly high electrical characteristics are not required.

(4) The electronic component 109 is mounted on the printed wiring board 101. The electronic component 109 is electrically connected to the lowermost signal transmission wiring 105 and the uppermost signal transmission wiring 105. The electronic component 109 electrically connected to the lowermost signal transmission wiring 105 is built in the lower electric insulating layer 103B. The electronic component 109 mounted on the uppermost signal transmission wiring 105 is mounted on the upper surface of the upper electric insulating layer 103A (printed wiring board 101). The electronic components 109 are arranged to face each other along the thickness direction of the printed wiring board 101. The auxiliary wiring 104 is arranged between the electronic components 109. The auxiliary wiring 104 is arranged so as to block both parts 109 and 109.

In this embodiment, the auxiliary wiring 104 is provided with the electromagnetic shielding layer 106. Moreover, the electromagnetic shielding layers 106 are provided on both surfaces of the auxiliary wiring 104 disposed between the layers of the electric insulating layer 103. Thereby, radiation noise can be suppressed efficiently. In this embodiment, the signal transmission wiring 105 is also provided with the electromagnetic shielding layer 106. This is a configuration adopted to give top priority to suppression of radiation noise. However, when it is desired to achieve both suppression of radiation noise and high-density mounting, the electromagnetic shielding layer 106 may be provided only on the auxiliary wiring 104 without being provided on the signal transmission wiring 105.

In the present embodiment, the electromagnetic shielding layer 106 is arranged between the electronic components 109 arranged to face each other in the thickness direction of the printed wiring board 101. A total of two electromagnetic shielding layers 106 are formed on both surfaces of the auxiliary wiring (ground) 104. As a result, electric interference between the electronic components 109 is more efficiently suppressed as compared with the configuration including only the auxiliary wiring (ground) 104.

In addition, in the configuration having the electromagnetic shielding layer 106, a ground having the same shielding strength can be formed with a smaller occupied area as compared with the configuration having no electromagnetic shielding layer 106. Therefore, the printed wiring board 101 can be further miniaturized, and the characteristic range of the electronic component 109 that can be considered to be mountable on the printed wiring board 101 is widened.

{Circle around (2)} Since the inner via 102 is formed without contacting the electromagnetic shielding layer 106, the conductive paste forming the inner via 102 does not contact the electromagnetic shielding layer 106. This prevents physical deterioration of the conductive paste and characteristic deterioration of the high-frequency signal transmitted through the inner via 102.

、 In the signal transmission wiring 105, an insulator film 107 is provided between the signal transmission wiring 105 and the electromagnetic shielding layer. Therefore, the characteristics of the high-frequency signal transmitted through the signal transmission wiring 105 do not deteriorate. Further, the radiation noise radiated from the inside of the printed wiring board 101 to the outside and the radiation noise entering the inside from the outside can be more efficiently suppressed. This is for the following reason. By forming the electromagnetic shielding layer 106 on the signal transmission wiring via the insulator film 107, it is possible to prevent external noise (unnecessary electromagnetic field) from affecting the electromagnetic field of the signal flowing through the signal transmission wiring 105. This is because it is reliably attenuated. Similarly, the unnecessary electromagnetic field from the signal flowing through the signal transmission wiring 105 is reliably suppressed by the electromagnetic shielding layer 106, so that the noise generated inside the substrate is less likely to leak to the outside.

In FIG. 1A, the auxiliary wiring 104 and the electromagnetic shielding layer 106 are provided so as to cover the upper surface of the electronic component 109 in the figure. However, as shown in FIG. 1B, the lower surface (terminal forming surface) of the electronic component 109 in the figure is changed. The auxiliary wiring 104 and the electromagnetic shielding layer 106 may be provided so as to cover. Further, as shown in FIG. 1C, the auxiliary wiring 104 and the electromagnetic shielding layer 106 may be provided so as to cover both the upper surface and the lower surface of the electronic component 109 in the drawing.

(Second embodiment)
FIG. 2 is a sectional view showing a printed wiring board with a built-in electronic component according to a second embodiment of the present invention. The printed wiring board 201 shown in FIG. The insulating plate 203 has two layers of electric insulating layers 203A and 203B integrated and laminated. The electric insulating layers 203A and 203B are made of a composite material in which an epoxy resin and an inorganic filler (such as fused silica or alumina) are mixed. The signal transmission wiring 205, the auxiliary wirings 204A and 204B, and the electronic component 209 are arranged between the electric insulating layers 203A and 203B. The auxiliary wirings 204A and 204B are arranged between the signal transmission wirings 205. One of the plurality of auxiliary wires 204A, 204B is connected to a ground potential. The other wiring 204B is not connected to a ground potential (not shown) and is a so-called non-connection wiring. Electron shielding layers 206 are formed on both surfaces of the auxiliary wirings 204A and 204B. The electromagnetic shielding layer 206 is provided on both surfaces of the auxiliary wirings 204A and 204B. The electromagnetic shielding layer 206 is made of a magnetic material having a magnetic loss. Electronic component 209 is electrically connected to signal transmission wiring 205. The electronic component 209 is built in the upper electric insulating layer 203A.

In this embodiment, auxiliary wirings 204A and 204B are arranged between adjacent signal transmission wirings 205 and 205, and electromagnetic shielding layers 206 are provided on both surfaces of the auxiliary wirings 204A and 204B. Therefore, electric mutual interference between the signal transmission lines 205 and 205 is more efficiently suppressed as compared with a configuration in which only the auxiliary lines 204AC and 204B are provided. Further, a ground having the same shield strength can be formed with a small area. Therefore, the printed wiring board can be further reduced in size. In addition, the range of characteristics of the mountable electronic component 209 is widened.

The auxiliary wiring 204A is connected to the ground potential. The auxiliary wiring 204A more efficiently suppresses electrical interference between the signal transmission wirings 205, 205.
(Third embodiment)
FIG. 3 is a sectional view of a printed wiring board 301 incorporating an electronic component according to a third embodiment of the present invention. The printed wiring board 301 has an insulating plate 303. The insulating plate 303 has four electric insulating layers 303A to 303D that are stacked and integrated. The electric insulating layers 303A to 303D are made of a composite material in which an epoxy resin and an inorganic filler (such as fused silica or alumina) are mixed. The signal transmission wiring 305, the auxiliary wirings 304A-304F, and the electronic components 309A-309D are arranged between the electric insulating layers 303A-303D, respectively.

(4) The electronic components 309A to 309D are mounted on the signal transmission wiring 305 and are electrically connected. The electronic components 309A and 309B are arranged on the same surface in the insulating plate 303 (between the electric insulating layers 303A and 303B), and are both embedded in the electric insulating layer 303B. The electronic component 309C and the electronic component 309D are disposed on the same surface in the insulating plate 303 (between the electric insulating layers 303C and 303D), and are both embedded in the electric insulating layer 303C. Thus, the electronic component group (309A, 309B) and the electronic component group (309C, 309D) are arranged on different surfaces. Electronic component 309A and electronic component 309C are arranged to face each other along the thickness direction of printed wiring board 301B. Electronic component 309B and electronic component 309D are arranged to face each other along the thickness direction of printed wiring board 301B.

(4) The auxiliary wirings 304C and 304D are arranged on the same surface in the insulating plate 303 (between the electric insulating layers 303B and 303C). The auxiliary wiring 304C is arranged at a position that blocks the electronic component 309A and the electronic component 309C. The auxiliary wiring 304D is arranged at a position blocking the electronic component 309B and the electronic component 309D.

(4) The auxiliary wiring 304E is arranged on the same plane as the electronic components 309A and 309B (between the electric insulating layers 303A and 303B). The auxiliary wiring 304E is arranged at a position blocking the electronic component 309A and the electronic component 309B. The auxiliary wiring 304F is arranged on the same plane as the electronic components 309A and 309B (between the electric insulating layers 303A and 303B). The auxiliary wiring 304F is arranged at a position that blocks the electronic component 309C and the electronic component 309D.

(4) The electromagnetic shielding layers 306 are provided on both surfaces of the auxiliary wirings 304C to 304F. The electromagnetic shielding layer 306 is made of a magnetic material having a magnetic loss. The electromagnetic shielding layer 306 is provided on the entire surface of the auxiliary wirings 304C to 304F. The auxiliary wirings 304C and 304E are connected to a ground potential (not shown). The auxiliary wirings 304D and 304F are not connected to the ground potential and are non-connection wirings.

In this embodiment, auxiliary wirings 304C to 304F are arranged between adjacent signal transmission wirings 305, 305 and between electronic components 309A to 309D, and electromagnetic shielding layers 306 are provided on both surfaces of the auxiliary wirings 304C to 304F. Therefore, electric mutual interference between the signal transmission wiring 305 and the electronic components 309A to 309D is more efficiently suppressed as compared with a configuration in which only the auxiliary wirings 304C to 304F are similarly provided. Further, a ground having the same shield strength can be formed with a small area. Therefore, the printed wiring board can be further reduced in size. In addition, the range of characteristics of the mountable electronic component is widened.

(4) Some of the auxiliary wirings 304C and 304E of the auxiliary wirings 304C to 304F are connected to the ground potential. The auxiliary wirings 304C and 304E further efficiently suppress electrical mutual interference between the signal transmission wirings 305 and between the electronic components 309A to 309D.

(Fourth embodiment)
FIG. 4 is a sectional view of a printed wiring board with a built-in electronic component according to a fourth embodiment of the present invention. 4A is a sectional view thereof, FIG. 4B is a sectional view taken along line aa ′ of FIG. 4A, FIG. 4C is a sectional view taken along line bb ′ of FIG. 4A, and FIG. 4E is a cross-sectional view taken along the line cc ′ of FIG. 4, and FIG. 4E is an enlarged view of a main part showing the arrangement of inner vias.

プ リ ン ト This electronic component built-in type printed wiring board 401 has an insulating plate 403. The insulating plate 403 has four layers of electric insulating layers 403A to 403D. An electronic component 409 is embedded between layers of the insulating plate 403. The signal transmission wiring 405, the first auxiliary wiring 404A, and the second auxiliary wirings 404B and 404C are arranged between the layers of the insulating plate 403. The signal transmission wiring 405 is connected to the electronic component 409. The electronic component 409 is mounted on the signal transmission wiring 405. The electronic component 409 is built in the insulating plate 403.

{Circle around (1)} The first auxiliary wiring 404A has a plate shape, and is arranged at a position covering the upper surface of the electronic component 409 in the figure. Here, the upper surface of the electronic component 409 indicates a component surface located on a side opposite to the terminal forming surface. The second auxiliary wirings 404B and 404C have a frame shape, and are arranged at positions surrounding the electronic component 409 in the drawing. The first auxiliary wiring 404A, the second auxiliary wiring 404B, and the second auxiliary wiring 404C are arranged on different surfaces in the insulating plate 403. Specifically, the first auxiliary wiring 404A is disposed between the electric insulating layers 403A and 403B. The first auxiliary wiring 404A is connected to the ground potential. The second auxiliary wiring 404B is disposed between the electric insulating layers 403B and 403C. The second auxiliary wiring 404C is disposed between the electric insulating layers 403C and 403D.

The printed wiring board 401 has an inner via 408 built therein. The inner via 408 is provided between the first auxiliary wiring 404A and the second auxiliary wiring 404B and between the second auxiliary wiring 404B and the second auxiliary wiring 404C. The first auxiliary wiring 404A and the second auxiliary wiring 404B are electrically connected by the inner via 408. The second auxiliary wiring 404B and the second auxiliary wiring 404C are electrically connected by the inner via 408. The second auxiliary wirings 404B and 404C are connected to the ground potential via the first auxiliary wiring 404A.

(4) Electromagnetic shielding layers 406 are formed on both surfaces of the first and second auxiliary wirings 404A-404C. The electromagnetic shielding layer 406 is provided on the whole of both surfaces of the first and second auxiliary wirings 404A-404C. The electromagnetic shielding layer 406 is made of a magnetic material having a magnetic loss. The electromagnetic shielding layer 406 is connected to the inner via 408. Thereby, the electromagnetic shielding layers 406 of each layer are electrically connected to each other. The electromagnetic shielding layer 406 is electrically connected to the first and second auxiliary wirings 404A-404C.

4E, a plurality of inner vias 408 connecting the first auxiliary wiring 404A and the second auxiliary wiring 404B are provided along the width direction 409a of the side surface of the electronic component 409, as shown in FIG. 4E. Similarly, a plurality of inner vias 408 connecting the second auxiliary wiring 404B and the second auxiliary wiring 404C are provided along the width direction 409a of the side surface of the electronic component 409. The facing direction 408a of the inner vias 408, 408 adjacent to each other is set non-parallel to the width direction 409a of the side surface of the electronic component 409. The facing directions 408a sequentially intersect.

In the printed wiring board 401, the signal transmission wiring 405, the inner via 408, and the like, which can ensure the reliability, cannot be formed in a region close to the electronic component 408. This is because, by incorporating the electronic component 409, the nearby electric insulating layer 403 is physically distorted. Therefore, when the electric insulating layer 403 is provided with the signal transmission wiring 405 and the inner via 408, the signal transmission wiring 405 and the inner via 408 are provided. 408 also results from physical distortion.

However, in the configuration of the present embodiment, the first and second auxiliary wirings 404A to 404C that do not require much reliability are arranged near the electronic component 409. Further, an inner via 408 for interlayer connection between the first and second auxiliary wirings 404A-404C is arranged near the electronic component 409.

As described above, in the present embodiment, the first and second auxiliary wirings 404A to 404C and the auxiliary wirings 404A to 404C are provided in the vicinity of the built-in electronic component 409 where the wiring and the structure for interlayer connection cannot be arranged conventionally. Is provided with an inner via 408 for interlayer connection. This makes it possible to suppress radiation noise from inside or outside the printed wiring board 401 without increasing the size of the printed wiring board 401.

Are electrically connected to the first and second auxiliary wirings 404A to 404C via inner vias 408 which are regularly arranged and distributed, so that the electronic component 409 is formed. , A simple three-dimensional shield is formed. Therefore, the radiation noise suppressing ability is improved as compared with the structure in which the electromagnetic shielding layer 406 is formed independently. Further, the radiation noise suppressing ability is further improved by dispersing the inner vias 408 with regularity. This is because the inner vias 408 can be more densely arranged along the width direction 408a of the side surface of the electronic component 409 by being distributed and arranged with regularity.

(Fifth embodiment)
FIG. 5A is a sectional view showing a first configuration of a wiring structure of a printed wiring board according to a fifth embodiment of the present invention. In this configuration, the electromagnetic shielding layers 506 are formed on both surfaces of the auxiliary wiring 504A connected to the ground potential. The electromagnetic shielding layer 506 is made of a magnetic material having a magnetic loss. An insulator film 507 is provided between the electromagnetic shielding layer 506 and the auxiliary wiring 504A.

(4) The electromagnetic shielding layer 506 is provided in the next area on the auxiliary wiring 504A. The electromagnetic shielding layer 506 is formed in the longitudinal region 504a of the auxiliary wiring 504A having a length of ４ of the wavelength corresponding to the frequency to be suppressed. The electromagnetic shielding layer 506 is not formed in the other region 504b of the auxiliary wiring 504A.

FIG. 5B is a cross-sectional view showing a second configuration of the present embodiment. In this configuration, the auxiliary wiring 504B (non-connection wiring) that is not connected to the ground potential is formed to have a length of half the wavelength corresponding to the frequency to be suppressed. Electromagnetic shielding layers 506 are provided on both surfaces of the auxiliary wiring 504B. No insulator film is provided between the electromagnetic shielding layer 506 and the auxiliary wiring 504B.

In FIGS. 5A and 5B, reference numeral 503 denotes an electric insulating layer.

In the first configuration of the present embodiment shown in FIG. 5A, the electromagnetic shielding layer 506 is selectively formed only in the longitudinal region 504a of the auxiliary wiring 504A having a length of １ ／ of the wavelength corresponding to the frequency to be suppressed. Is done. This electromagnetic shielding layer 506 functions as a resonator at the frequency to be suppressed. This suppresses unnecessary radiation of a specific frequency inside the printed wiring board.

In the second configuration of the present embodiment shown in FIG. 5B, the auxiliary wiring 504B is formed over a length of 波長 of the wavelength corresponding to the frequency to be suppressed, and the electromagnetic shielding layers are formed on both surfaces of the auxiliary wiring 504B. 506 is formed. This auxiliary wiring 504B acts as a resonator at the frequency to be suppressed. This suppresses unnecessary radiation of a specific frequency inside the printed wiring board.

The embodiments of the present invention have been described above. Next, a method for manufacturing a printed wiring board according to the present invention will be described with reference to FIG. Although the manufacturing method described below is similar to the printed wiring board 101 of the first embodiment, the auxiliary wiring 604 includes an auxiliary wiring 604A connected to the ground potential and an auxiliary wiring 604B not connected to the ground potential. This is a method for manufacturing a printed wiring board having:

First, as shown in FIG. 6A, a transfer forming material 617 is prepared. The auxiliary wiring 604A (ground potential connection), the signal transmission wiring 605, and the auxiliary wiring 604B (ground potential non-connection) are formed on the prepared transfer forming material 617. Note that these wirings 604A, 604B, and 605 are formed on the transfer forming material 617 by a printing method or a subtractive method.

Next, an insulator film 607 is selectively formed on the signal transmission wiring 605. The insulator film 607 is formed on the signal transmission wiring 605 by, for example, a printing method or a subtractive method.

Next, an electromagnetic shielding layer 606 made of a magnetic material having a magnetic loss is formed on the insulator film 607 (signal transmission wiring 605), the auxiliary wiring 604A, and the auxiliary wiring 604B. The electromagnetic shielding layer 606 is formed on the insulator film 607 and the auxiliary wirings 604A and 604B by, for example, a printing method or a subtractive method.

Next, an inner via insertion hole 608 reaching the signal transmission wiring 605 is formed in the electromagnetic shielding layer 606 and the insulator film 605 on the signal transmission wiring 605. The inner via insertion hole 608 is formed at a position facing the inner via 602 to be formed later. The inner via insertion hole 608 is formed by, for example, a subtractive method. The inner via insertion hole 608 is formed slightly larger in diameter than the diameter of the inner via 602. Further, an electronic component 609 is mounted at a predetermined position on the signal transmission wiring 605 and is electrically connected.

Meanwhile, the electric insulating layer 603B is prepared. Electronic component storage holes 610 are formed in prepared electric insulating layer 603B. The electronic component storage hole 610 has a size in which the electronic component 609 enters. Further, a through hole is formed in the electric insulating layer 603B. The conductive paste is filled in the formed through hole. The conductor paste filled in the through holes forms the inner via 602.

Next, the transfer forming material 617 is attached to the electric insulating layer 603B. The transfer forming material 617 is arranged such that the formation surface of the auxiliary wirings 604 </ b> A and 604 </ b> B faces the electrical insulating layer 603. Further, at this time, the transfer forming material 617 is arranged so that the electronic component 609 enters the electronic component storage hole 610. Thus, the auxiliary wirings 604A and 604B and the signal transmission wiring 605 are transferred to the electric insulating layer 603B together with the insulating film 607 and the electromagnetic shielding layer 605. After the transfer, the transfer forming material 607 is removed from the electric insulating layer 603B. The signal transmission wiring 605 after the transfer is in direct contact with the inner via 602 as shown in FIG. At this time, the insulator film 607 and the electromagnetic shielding layer 606 do not abut on the inner via 603 through the inner via insertion hole 608.

Next, an insulator film 607 and an electromagnetic shielding layer 606 are formed on the signal transmission wiring 605 and the auxiliary wirings 604A and 604B on the electric insulating layer 603B. The insulator film 607 and the electromagnetic shielding layer 606 are formed by, for example, a printing method or a subtractive method.

Next, an inner via insertion hole 608 reaching the signal transmission wiring 605 is formed in the electromagnetic shielding layer 606 and the insulator film 605 on the signal transmission wiring 605. The inner via insertion hole 608 is formed at a position facing the inner via 602 to be formed later. The inner via insertion hole 608 is formed by, for example, a subtractive method. The inner via insertion hole 608 is formed slightly larger in diameter than the diameter of the inner via 602.

Next, another electrical insulating layer 603A is prepared. 6A and 6B described above, the inner via 602, the signal transmission wiring 605, the auxiliary wirings 604A and 604B, the electromagnetic shielding layer 606, and the insulating film are formed. 607 and an inner via insertion hole 608 are formed. However, the signal transmission wiring 605, the auxiliary wirings 604A and 604B, the electromagnetic shielding layer 606, and the insulator film 607 are formed only on one surface of the electric insulating layer 603. After that, another electronic component 609 is mounted on the signal transmission wiring 605 of the electric insulating layer 603.

(4) Next, the electrical insulating layers 603B and 603A are laminated and integrated to form an insulating plate 603. At this time, the electric insulating layer 603A in which various wirings are formed on one surface is stacked with the wiring non-forming surface facing the electric insulating layer 603B on the other side. Further, another electric insulating layer 603B is stacked with the inner via insertion hole forming surface facing the electric insulating layer 603 on the other side. Thereby, the printed wiring board 601 is formed.

In this manufacturing method, the electromagnetic shielding layer 606 is fixed onto the transfer forming material 617 and then transferred to the electric insulating layers 603B and 603A. Formed selectively.

By providing the inner via insertion holes 608, the inner vias 602 can be arranged apart from the electromagnetic shielding layer 606 and the insulator film 607. Therefore, the conductive paste of the inner via 602 does not come into contact with the components of the electromagnetic shielding layer 606 and the insulator film 607. Thus, deterioration of the high-frequency characteristics of the high-frequency signal transmitted through the inner via (conductive paste) 602 is suppressed.

Further, by forming the electromagnetic shielding layer 606 again on the wirings 605, 604A, 604B after being transferred to the electric insulating layers 603B, 603A, the electromagnetic shielding layers 606 can be formed on both surfaces of the wirings 605, 604A, 604B. it can. This makes it possible to further suppress radiation noise as compared with a configuration in which the electromagnetic shielding layer 606 is formed only on one side of the wirings 605, 604A, and 604B.

In the above-described manufacturing method, the printed wiring board of the present invention was manufactured by the transfer method. In addition, the printed wiring board of the present invention can be manufactured by using the subtractive method.

FIG. 1A is a cross-sectional view of a printed wiring board showing a first embodiment of the present invention, FIG. 1B is a cross-sectional view of a printed wiring board showing a modification of the first embodiment, and FIG. FIG. 9 is a cross-sectional view of a printed wiring board showing a modification of the first embodiment. It is sectional drawing of the electronic component built-in type printed wiring board which shows 2nd Embodiment of this invention. FIG. 9 is a cross-sectional view of a wiring layer of a printed wiring board according to a third embodiment of the present invention. 4A to 4D are cross-sectional views of a printed wiring board with a built-in electronic component showing a fourth embodiment of the present invention, and FIG. 4E is an enlarged view of a main part of the fourth embodiment. FIG. 5A is a cross-sectional view of a printed wiring board showing a first configuration of the fifth embodiment of the present invention, and FIG. 5B is a printed circuit showing a second configuration of the fifth embodiment of the present invention. It is sectional drawing of a wiring board. 6A to 6D are explanatory diagrams of the method for manufacturing a printed wiring board according to the present invention. It is sectional drawing of the conventional example of a printed wiring board.

Explanation of reference numerals

Reference Signs List 101 multilayer printed wiring board 102 inner via 103 insulating plate 103A, 103B electric insulating layer 104 auxiliary wiring 105 signal transmission wiring 106 electromagnetic shielding layer 107 insulating film
108 inner via insertion hole 109 electronic components 301A, B multilayer printed wiring board 303 insulating plate 303A, B electrical insulating layer 304A, B (NC) auxiliary wiring 304C-F auxiliary wiring 305 signal transmission wiring 306 electromagnetic shielding layer 309 electronic component 309A- D electronic component 401 electronic component built-in multilayer printed wiring board 403 insulating layer 404A first auxiliary wiring 404B, C second auxiliary wiring 405 signal transmission wiring 406 electromagnetic shielding layer 408 inner via 408a facing direction of inner via 409 electronic component 409a 504A auxiliary wiring 504A auxiliary wiring 504a Longitudinal area 504b Other area 506 Electromagnetic shielding layer 507 Insulator film 602 Inner via 603 insulating layer 604A auxiliary wiring (ground potential connection)
604B auxiliary wiring (ground potential not connected) 605 signal transmission wiring 606 electromagnetic shielding layer 607 insulating film 608 inner via insertion hole 617 transfer forming material 703 inner insulating layer 704A, B auxiliary wiring 705 signal transmission wiring 706 electromagnetic shielding layer 707 Insulator film 718 conductive foil

Claims (24)

An insulating plate composed of a plurality of laminated electrical insulating layers,
Electronic components built into the insulating plate,
Signal transmission wiring provided between layers of the electrical insulating layer,
Auxiliary wiring provided on the insulating plate in an electrically insulated state with the signal transmission wiring,
An electromagnetic shielding layer covering at least a part of the auxiliary wiring,
Printed wiring board having. The electromagnetic shielding layer, composed of a magnetic material having a magnetic loss,
The printed wiring board according to claim 1. Connecting the auxiliary wiring to a ground potential;
The printed wiring board according to claim 1. Providing an insulator film between the auxiliary wiring and the electromagnetic shielding layer,
The printed wiring board according to claim 1. The signal transmission wiring has wiring parts facing each other, and the auxiliary wiring is provided between the facing wiring parts.
The printed wiring board according to claim 1. The auxiliary wiring is provided between the signal transmission wiring and the electronic component,
The printed wiring board according to claim 1. The auxiliary wiring is provided so as to face a component surface having a higher intensity of unnecessary radiation radiated by the electronic component among both component surfaces of the electronic component,
The printed wiring board according to claim 1. The auxiliary wiring is provided to face the terminal forming surface of the electronic component,
The printed wiring board according to claim 1. The auxiliary wiring is provided to face a component surface located on a side opposite to a terminal forming surface of the electronic component,
The printed wiring board according to claim 1. The auxiliary wiring is provided so as to face each of a terminal forming surface of the electronic component and a component surface located on the opposite side thereof,
The printed wiring board according to claim 1. Providing a plurality of the electronic components, providing the auxiliary wiring between the plurality of electronic components,
The printed wiring board according to claim 1. The auxiliary wiring is provided around and surrounding the electronic component,
The printed wiring board according to claim 1. The auxiliary wiring includes a first auxiliary wiring provided to cover one surface of the electronic component, and a second auxiliary wiring provided around and surrounding the electronic component,
A conductor for electrically connecting the first auxiliary wiring and the second auxiliary wiring is provided on the electrical insulating layer;
The printed wiring board according to claim 1. A plurality of the conductors are provided so as to surround the side surface of the electronic component, and the opposing directions of the mutually adjacent conductors are non-parallel to the width direction of the side surface of the electronic component, and the opposing directions sequentially intersect. Placing conductors,
The printed wiring board according to claim 13. Providing the electromagnetic shielding layer on both surfaces of the auxiliary wiring,
The printed wiring board according to claim 1. Further providing an electromagnetic shielding layer covering at least a part of the signal transmission wiring,
The printed wiring board according to claim 1. Covering both surfaces of the signal transmission wiring with the electromagnetic shielding layer,
The printed wiring board according to claim 16. An insulating film is provided between the signal transmission wiring and the electromagnetic shielding layer covering the signal transmission wiring,
The printed wiring board according to claim 16. The signal transmission wiring is provided on both sides of the electrical insulation layer, conductors connecting the signal transmission wirings on the both sides are provided through the electrical insulation layer, and the insulator film and the electromagnetic shielding layer are formed of the conductor. To be spaced apart from
The printed wiring board according to claim 18. The electric insulating layer is composed of a composite material formed by mixing an epoxy resin and an inorganic filler,
The printed wiring board according to claim 1. Connecting the auxiliary wiring to a ground potential, and setting the length of the electromagnetic shielding layer to a length of 1/4 of the peripheral wavelength to be suppressed;
The printed wiring board according to claim 1. Setting the length of the auxiliary wiring to の 長 of the wavelength to be suppressed;
The printed wiring board according to claim 1. An insulating plate composed of a plurality of electrically insulating layers stacked, an electronic component built in the insulating plate, a signal transmission line provided between layers of the electric insulating layer, and the signal transmission line in an electrically insulated state. A method of manufacturing a printed wiring board having an auxiliary wiring provided on the insulating plate and an electromagnetic shielding layer covering at least a part of the auxiliary wiring,
Preparing a transfer forming material, patterning the auxiliary wiring on the transfer forming material,
Patterning an electromagnetic shielding layer on the auxiliary wiring on the transfer forming material;
Transferring the auxiliary wiring layer from the transfer forming material to the electrical insulating layer by bringing the electromagnetic shielding layer into contact with the electrical insulating layer;
A method for manufacturing a printed wiring board including: Patterning the electromagnetic shielding layer on the auxiliary wiring layer transferred to the electrical insulating layer, further comprising:
A method for manufacturing the printed wiring board according to claim 23.

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