JP2002289991A - Low emi circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that the conventional digital circuit board is intended to connect digital wirings on a circuit surface between boards, without taking account of the IC layout or terminal order, resulting in that board interconnections are located away from ICs because of cross wiring processes, and if the most portion of the board is occupied by digital circuits including multi-terminal and narrow pitched ICs occupy the most portion of the board, the wirings are concentrated to make digital wirings run long around. SOLUTION: A double-sided circuit board 13 having at least a first semiconductor IC mounted thereon is connected to a multilayer circuit board 11 having four layers or more and at least one semiconductor IC mounted thereon with avoidable cross wirings through a board interconnection 40. The interconnection 40 is composed of digital signal terminal lines arranged so that the terminal order coincides with that of the semiconductor IC and ground lines facing the digital signal terminal lines, laid to face the signal terminals of the semiconductor IC every semiconductor IC and connected with each semiconductor IC, without forming any cross wiring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board for reducing radiated noise from a built-in digital circuit, and an electronic device using the circuit board.

[0002]

2. Description of the Related Art In recent years, in digital circuits of electronic equipment, the number of terminals of semiconductor ICs has increased along with the increase in processing speed, and the number of wirings between semiconductor ICs has also continued to increase. A semiconductor IC having a large number of terminals has a complicated wiring connection on a circuit board, and is likely to be a source of radiated noise due to crossing of wiring and long wiring. As described above, in a circuit board having a built-in digital circuit, it is becoming difficult to take measures against unnecessary radiation noise in combination with an increase in signal frequency.

Conventionally, low-cost boards such as a single-sided circuit board and a double-sided circuit board have formed a digital ground, which is a return path for a digital signal, near or immediately below a signal line to reduce unnecessary radiation noise. That is, by forming a digital signal line and a digital ground as a pair, generation of unnecessary radiation noise has been suppressed. However, in a digital circuit having a complicated and extremely large number of wiring patterns in recent years, the number of cross wirings in which wiring layers are changed with vias increases, making it difficult to form a digital ground pattern near or directly below a signal line, and increasing the wiring length. As a result, the deterioration of the unnecessary radiation noise characteristics has become unavoidable. Further, a semiconductor IC having a lattice-like terminal arrangement represented by a BGA or a semiconductor IC having multiple terminals and a narrow pitch is a semiconductor IC.
Since a plurality of layers are required for drawing out the wiring from the C terminal, a multilayer substrate having four or more layers is essential. For this reason, the opportunity that a low-cost substrate can be used is reduced, and the cost of the substrate is increased.

On the other hand, in a circuit board in which a digital circuit and a power supply circuit or an analog circuit are mixed, a digital circuit section for handling a high-speed signal is provided on another four-layer circuit board in which a digital ground serving as a signal return path is easily formed. A separated configuration is disclosed in Japanese Patent Application Laid-Open No. H11-119862. In this configuration, the generation of unnecessary radiation noise is suppressed by separating the digital circuit section into four-layer circuit boards and shortening the digital signal wiring. Further, the remaining circuits such as a power supply circuit and an analog circuit are arranged on a single-sided circuit board or a double-sided circuit board to reduce the cost of the board.

[0005] Fig. 13 shows a structural diagram thereof. The circuit board in FIG. 13 includes a double-sided circuit board 107 and a four-layer circuit board 1.
06 and a connector 108. The four-layer circuit board 106 includes a semiconductor IC 1 for processing high-speed digital signals.
01 and 102 and connection wiring 109 for connecting the semiconductor ICs 101 and 102 and the connector 108 are provided.

The double-sided circuit board 107 includes a semiconductor IC 10
Semiconductor IC 1 for inputting / outputting digital signals to / from digital signal generators 1 and 102
03, 104, 105, and semiconductor ICs 103, 104,
A connection wiring 110 for connecting the connector 105 and the connector 108 is provided.

[0007] The connector 108 is provided between the double-sided circuit board 107 and the four-layer circuit board 106, and electrically connects the two.

[0008]

However, even when a digital circuit including a multi-terminal and narrow-pitch semiconductor IC that handles high-speed signals occupies a large part of the substrate, even if the substrate has a configuration as shown in FIG. The size of the multilayer substrate on which the digital circuit is mounted increases, and the cost increases. Conversely, if part of the digital circuit is mounted on a low-cost double-sided circuit board in order to reduce costs, the number of cross wirings of the semiconductor IC circuit increases, and it is difficult to form a digital ground pattern near or directly below the signal line. Become. Further, there has been a problem that the length of the wiring is long and the unnecessary radiation noise characteristics are deteriorated.

As a solution to the above problem, at least one of a multi-terminal and narrow-pitch semiconductor IC having a large number of wires between terminals and inevitable cross wiring is mounted on a low-cost single-sided circuit board or a double-sided circuit board. There is a digital circuit board shown in FIG. 14 in which a semiconductor IC is separately mounted on a small multilayer board of four or more layers in which all intersections related to the semiconductor IC are wired and connected by connectors. As a result, it has become possible to arrange the connection between the semiconductor IC on the low-cost single-sided circuit board or the double-sided circuit board and the multilayer board by non-intersecting wiring.

A digital circuit board shown in FIG. 14 includes a single-sided circuit board 207, a multilayer circuit board 206, and a connector 2
08. The multi-layer circuit board 206 includes semiconductor ICs 201 and 202 that process high-speed digital signals, a wiring 211 between semiconductor ICs that connects the semiconductor IC 201 and the semiconductor IC 202 by multi-layer wiring, a semiconductor IC 201 and a semiconductor IC 201.
There is provided a connection wiring 209 that connects the connector 02 and the connector 208 by a multilayer wiring.

The single-sided circuit board 207 includes a semiconductor IC 20
A semiconductor IC 2 for inputting / outputting digital signals to / from the IC 202
03, 204, 205 and semiconductor ICs 203, 204, 2
And a connection wiring 210 for connecting the semiconductor ICs 203, 204, and 205 and the connector 208 without crossing each other.

The connector 208 is provided between the multilayer circuit board 206 and the single-sided circuit board 207, and electrically connects the two. However, the digital circuit board having the above-described configuration is intended only to connect the digital wiring on the circuit diagram between the boards without considering the arrangement and the terminal order of the semiconductor ICs. Therefore, the connector 208 is disposed at a position away from the semiconductor IC for the cross wiring processing, and the wiring is concentrated and the first connection wiring 209 and the second connection wiring 210
However, there is a problem that the wire is drawn around for a long time.

Further, the digital ground in the connector 208 is not arranged for each digital signal terminal, but is shared by a plurality of digital signal terminals. In such a terminal configuration of the connector 208, the distance between each digital signal terminal and the digital ground is different. As a result, the path to the digital ground, which is the return path of the digital signal, is routed, and there is also a problem that unnecessary radiation noise is generated.

Therefore, an object of the present invention is to provide a digital circuit including a semiconductor IC on a single-sided circuit board or a double-sided circuit board having a short digital wiring and a multi-terminal and narrow-pitch semiconductor IC occupying most of the substrate. An object of the present invention is to provide a low-cost digital circuit board that does not cause deterioration of unnecessary radiation noise characteristics.

[0015]

A low EMI digital circuit board according to the present invention includes a first circuit board on which at least one integrated circuit having a plurality of signal terminals is mounted, and a low EMI digital circuit board mounted on the first circuit board. In connection with an integrated circuit, between a second circuit board on which at least one integrated circuit in which cross wiring is unavoidable is mounted, and a board for electrically connecting the first circuit board and the second circuit board It consists of a connection part,
The board-to-board connection portion is provided between the first circuit board and the second circuit board so as to face each integrated circuit mounted on the first circuit board, and A plurality of signal terminals for transmitting a predetermined signal, and a plurality of ground terminals provided at least in the vicinity of each of the signal terminals and connected to a ground unit for providing a reference potential, and mounted on the first circuit board And a wiring connecting the signal terminals of the integrated circuit and the signal terminals of the inter-substrate connection portion corresponding to the integrated circuit.

A connector is used for the board-to-board connection.

Each of the signal terminals and each of the ground terminals of the inter-substrate connection portion are made of a conductive metal ball.

The metal ball is provided between the first circuit board and the second circuit board.
And a circuit board is brazed via a conductive metal.

The invention is characterized in that a shielded flat cable is used for the board-to-board connection part.

The first circuit board is a double-sided circuit board.

The first circuit board is a multilayer circuit board having four or more layers.

The second circuit board is a multilayer circuit board having four or more layers.

[0023] A conductive metal box is provided so as to cover at least the integrated circuit mounted on the first circuit board, and is electrically connected to a plurality of ground terminals of the inter-board connection portion. And An integrated circuit mounted on the second circuit board is provided between the integrated circuit and the first circuit board, and a plurality of ground terminals of the inter-substrate connecting portion are continuously arranged so as to surround the integrated circuit. It is characterized by being arranged regularly.

[0024] The plurality of ground terminals of the inter-substrate connecting portion are continuously arranged so as to surround the plurality of signal terminals of the inter-substrate connecting portion.

[0025] A conductive and heat conductive sheet provided on the integrated circuit mounted on the second circuit board and connected to the ground is provided.

The second circuit board is a chip size package. An electronic apparatus using the low EMI digital circuit board according to claim 1.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a multilayer circuit board which suppresses the generation of unnecessary radiation noise due to cross wiring, although the digital circuit board is relatively expensive, and the generation of unnecessary radiation noise due to cross wiring. Although it is not effective, it is divided into a low-cost double-sided circuit board, the cross wiring is concentrated on the multilayer circuit board, and the wiring of the double-sided circuit board is made non-crossing, so that it is low-cost and unnecessary radiation noise A low EMI circuit board effective for suppression is realized.

It should be noted that the term "intersection of the wirings arranged on the circuit board" means that a plurality of wirings on the circuit board are arranged with their circuit surfaces changed by vias of the circuit board, and each wiring crosses three-dimensionally on the circuit board. Good, cross wiring means wiring arranged in such a manner. In addition, non-intersecting means that a plurality of wirings do not cross three-dimensionally on a circuit board, and non-intersecting wiring means wiring arranged as such. Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 12.

(Embodiment 1) FIG. 1 is a schematic configuration diagram showing a digital circuit board 10 according to Embodiment 1 of the present invention.

The digital circuit board 10 of the present invention comprises a multilayer circuit board 11, a double-sided circuit board 13, and board-to-board connecting portions 41, 42, 43 for connecting the multilayer circuit board 11 and the double-sided circuit board 13. Be composed. In FIG. 1, only the semiconductor IC is illustrated on the multilayer circuit board 11 and the double-sided circuit board 13 for convenience of explanation, but it goes without saying that other electronic components are mounted. Hereinafter, the connection of the semiconductor IC will be mainly described.

On the multilayer circuit board 11, semiconductor ICs 1, 3
Are mounted, and these semiconductor IC1 and semiconductor IC3
Are electrically connected via the semiconductor IC connection wiring 2. In the multilayer circuit board 11, all of the wirings that are inevitable to intersect are provided.

The semiconductor IC 1 is a semiconductor IC for processing digital signals at a high speed, and has a large number of digital signal terminals at a narrow pitch. For this reason, a multilayer circuit board having four or more layers is required for wiring connection from the signal terminals. Semiconductor IC3
Is a semiconductor IC such as a semiconductor memory that exchanges digital signals with the semiconductor IC 1. Semiconductor IC1 and Semiconductor I
In the connection with C3, it is generally unavoidable that the wires cross. Therefore, a semiconductor IC connecting them
The connection wiring 2 is arranged by cross wiring.

The multi-layer circuit board 11 is further provided with inter-substrate wiring 17, and the semiconductor ICs 1 and 3 and the inter-substrate connection 4
1, 42 and 43 are electrically connected. In the inter-substrate wiring 17, each wiring is arranged by cross wiring.

A semiconductor IC 5,
7 and 9 are mounted, and a semiconductor IC is provided between each semiconductor IC.
They are electrically connected via the C connection wiring 8. Also,
On the double-sided circuit board 13, board-to-board connecting portions 41, 42, 4
3, a multilayer circuit board 11 is provided. In the double-sided circuit board 13, all the wirings connecting the semiconductor ICs are performed by non-crossing wirings. Further, the double-sided circuit board 13 is provided with a multilayer circuit board 11 via a board-to-board connection portion 40.

The semiconductor ICs 5, 7, 9 are semiconductor ICs for transmitting and receiving digital signals to and from the semiconductor IC 1 or the semiconductor IC 3, and are provided on a double-sided circuit board 13 different from the position where the multilayer circuit board 11 is arranged. Also, semiconductor ICs 5, 7, 9
Are arranged so that the wirings of the semiconductor IC connection wiring 8 do not cross each other.

The double-sided circuit board 13 is further provided with inter-substrate wiring 19, and electrically connects the semiconductor ICs 5, 7, 9 with the inter-substrate connecting portions 41, 42, 43, respectively. The inter-substrate wiring 19 is arranged linearly without crossing each wiring. The inter-substrate connection portions 41, 42, 43
The semiconductor ICs 5, 7, 9 on the double-sided circuit board 13 are provided between the multilayer circuit board 11 and the double-sided circuit board 13.
The upper semiconductor ICs 5, 7, 9 are electrically connected. For example, the board-to-board connection section 41 is a connection section corresponding to the semiconductor IC 5 on the double-sided circuit board 13, and connects the semiconductor IC 5 to the semiconductor IC 1 on the multilayer circuit board 11. FIG. 2 is an enlarged view of the inter-substrate connecting portion 41.

The inter-substrate connecting portion 41 is provided so as to substantially face the semiconductor IC 5. In this embodiment, a connector is used as the board-to-board connecting portion 41. The board-to-board connection section 41 has a digital signal terminal row 41a and a ground terminal row 41b.

The digital signal terminal row 41a is a terminal connected to a signal line for transmitting a predetermined digital signal. Each terminal of the digital signal terminal row 41a connects the semiconductor IC 5 and the semiconductor IC 1 via the inter-board wiring 19 and the inter-board wiring 17. The digital signal terminal row 41a is a semiconductor I
It may be provided at a position substantially facing the digital signal terminal 5a of C5. At this time, the digital signal terminal row 41a
It is preferable that the inter-substrate wiring 19 connecting the semiconductor IC 5 in the double-sided circuit board 13 is arranged as short as possible. This is because the shorter the wiring length, the more the generation of radiation noise can be suppressed. The terminals of the digital signal terminal row 41a are associated with each other so that the wires connecting the terminals of the signal terminal 5a do not cross each other. That is, the terminal sequence of the digital signal terminal row 41a is associated with the terminal arrangement of the digital signal terminal 5a. Each terminal of the digital signal terminal row 41a thus associated is linearly connected to each terminal of the digital signal terminal 5a of the semiconductor IC 5 via the wiring 19 between the substrates. Further, each terminal of the digital signal terminal row 41a is connected to each terminal of a predetermined digital signal terminal 1a via each wiring of the inter-board wiring 17 in the multilayer circuit board 11.

The ground terminal row 41b is a terminal arranged near each terminal for each terminal of the digital signal terminal row 41a. Each terminal of the ground terminal row 41b is arranged so as to face each terminal of the digital signal terminal row 41a. Further, each terminal of the ground terminal row 41b is arranged such that each terminal of the opposing digital signal terminal row 41a is located closer to the semiconductor IC 5 side. Ground terminal row 41
Each terminal b is connected to a digital ground (not shown) of the multilayer circuit board 11 and the double-sided circuit board 13.

The other inter-substrate connecting portions 42 and 43 have the same configuration as the inter-substrate connecting portion 41. The inter-substrate connecting portion 42 corresponds to the semiconductor IC 7, and the inter-substrate connecting portion 43 corresponds to the semiconductor IC 7.
9 corresponds.

The digital circuit board 10 according to the first embodiment configured as described above has a multi-layer circuit board 11 in which all the wirings that cannot be avoided intersect and a double-sided circuit board 13 in which the wirings do not intersect. It is divided, and both are connected via the inter-substrate connection part 40. In particular, by arranging all the cross wirings on the multilayer circuit board 11 which can easily form the digital ground corresponding to the digital signal wiring,
Generation of unnecessary radiation noise can be suppressed.

The inter-substrate connecting portions 41, 42, and 43 substantially face the vicinity of the semiconductor ICs 5, 7, and 9, respectively.
And they are individually provided so as to be parallel. This allows
Concentration of the wiring on the inter-substrate connecting portion 40 can be avoided, and the routing of the wiring can be reduced. As a result, it is possible to suppress the generation of unnecessary radiation noise.

The inter-substrate connecting portions 41, 42, 43
Digital signal terminal array 41 associated with the arrangement order of the digital signal terminals of the semiconductor ICs 5, 7, and 9
a, 42a and 43a. This makes it easy to arrange the inter-substrate wiring 19 in a non-intersecting wiring, thereby suppressing the generation of unnecessary radiation noise.

Further, the inter-substrate connecting portions 41, 42, 43
A ground terminal row 41b that is an individual digital ground for each terminal of the digital signal terminal rows 41a, 42a, 43a;
42b and 43c. As a result, it is possible to reduce unnecessary radiation noise that has been generated because the terminal for digital signals in the connector has conventionally shared the terminal serving as the digital ground. As described above, the digital circuit board 10 of the present invention can be a digital circuit board in which a digital ground serving as a signal return path is formed in the vicinity of a digital signal wiring or on a desired surface. As a result, it is possible to realize a digital circuit board in which unnecessary radiation noise is significantly reduced.

The wirings arranged on the double-sided circuit board 13 do not all intersect, but the double-sided circuit board 13 may be provided with crossed wirings as long as the influence of unnecessary radiation noise is small. Needless to say.

If a flat cable with a shield is used instead of the inter-substrate connecting portions 41, 42, 43, the connection with the semiconductor IC on the double-sided circuit substrate 13 in a wider range than the multilayer circuit substrate 11 can be shortened. In addition, they can be arranged with no crossing wiring, and the occurrence of unnecessary radiation noise can be further suppressed.

Further, if the double-sided circuit board 13 is replaced with a four-layer circuit board, one of which is a wide inner-layer digital ground, signals can also be supplied to the cross wiring other than those connected to the board-to-board connection portions 41, 42, and 43. A return path can be formed, and the generation of unnecessary radiation noise can be further suppressed.

The inter-substrate wiring 19 is connected to the double-sided circuit board 13.
Wiring is performed only on one of the circuit surfaces and the entire surface of the other circuit surface is set to a wide digital ground, so that generation of unnecessary radiation noise can be further suppressed.

Further, by forming the multilayer circuit board 11 in a chip size package and miniaturizing it, it is possible to further suppress the generation of unnecessary radiation noise.

In FIG. 1, a digital ground, which is a return path of the digital signal wiring, is omitted for the sake of simplicity of the drawing. However, it is assumed that the digital ground is formed near the digital signal wiring or on a circuit surface immediately below. I do. Furthermore, although the multilayer circuit board 11 and the double-sided circuit board 13 are drawn separately, in practice, the multilayer circuit board 11 is installed on the double-sided circuit board 13 via the inter-substrate connection portions 41, 42, 43. ing. (The same applies to the following figures.)

Also, such a digital circuit board 10
Has an effect that it can be applied to all digital electronic devices that require a digital circuit such as a television and a video.

(Embodiment 2) FIG. 3 is a schematic configuration diagram showing a digital circuit board 50 according to Embodiment 2 of the present invention. FIG. 5 is a schematic sectional view taken along the line AA in FIG.

As shown in FIG. 3, the digital circuit board 50 of the present embodiment is basically the same as that of the first embodiment, but instead of the inter-board connection portions 41, 42, and 43,
The difference is that inter-substrate connection portions 51, 52, and 53 are provided, and inter-substrate ground connection portion 55 is provided. In FIG. 3, the board connecting portions 51, 52, 53 and the inter-board ground connecting portion 55 are drawn on both the multilayer circuit board 11 and the double-sided circuit board 13, but this is for convenience of explanation.
Actually, it is a component provided between the multilayer circuit board 11 and the double-sided circuit board 13. (The same applies to the following drawings.) Hereinafter, differences from the first embodiment will be described in detail.

The inter-board connection portions 51, 52 and 53 electrically connect the electronic components on the multilayer circuit board 11 and the electronic components on the double-sided circuit board 13. For example, the board-to-board connection 51
Connects the semiconductor IC 1 on the multilayer circuit board 11 and the semiconductor IC 5 on the double-sided circuit board 13.

FIG. 4 is an enlarged view of the inter-substrate connecting portion 51.
The board-to-board connection unit 51 includes a digital signal terminal row 51a and a ground terminal row 51b.

The digital signal terminal row 51a is a terminal connected to a signal line for transmitting a predetermined digital signal. The digital signal terminal row 51a is composed of a semiconductor IC5 and a semiconductor IC
1 is connected via an inter-board wiring 19 and an inter-board wiring 17. The digital signal terminal row 51a is a row of metal balls brazed to the inter-board wiring 17 and the inter-board wiring 19 with a conductive metal. This metal ball becomes a terminal of the digital signal terminal row 51a. The metal sphere used here is made of conductive metal and has a diameter of 0.9 to 1.0 mm, but is not limited thereto. In other words, any material can be used as long as conduction between the inter-substrate wiring 17 and the inter-substrate wiring 19 is possible. Further, as shown in FIG. 5, the digital signal terminal row 51a is formed by connecting the multilayer circuit board 11 to the double-sided circuit board 13.
It also plays the role of a support when arranging it. Therefore,
It is better to use a material having a predetermined strength as the material used for the terminals of the digital signal terminal row 51a.

In each terminal of the digital signal terminal row 51a, a metal ball is arranged in a row so as to substantially face each of the digital signal terminals 5a of the semiconductor IC 5. At this time, it is preferable that the terminals of the digital signal terminal row 51a are arranged so that the inter-board wiring 19 connecting the semiconductor IC 5 in the double-sided circuit board 13 is as short as possible. This is because the shorter the wiring length, the more the generation of radiation noise can be suppressed. Further, the terminals of the digital signal terminal row 51a are associated with each other so that the wires connecting the terminals of the signal terminal 5a do not cross each other. That is, the terminal order of the digital signal terminal row 51a is associated with the terminal arrangement of the digital signal terminals 5a. Each terminal of the digital signal terminal row 51a thus associated is linearly connected to each terminal of the digital signal terminal 5a of the semiconductor IC 5 via the inter-substrate wiring 19. Furthermore, each terminal of the digital signal terminal row 51a is connected to the multilayer circuit board 11
In the above, the semiconductor I
C1 is connected to a predetermined digital signal terminal 1a.

Preferably, the digital signal terminal row 5
When providing 1a, the pitch between the metal balls is made to match the pitch of the digital signal terminals 5a of the semiconductor IC5. Thereby, each terminal of the digital signal terminal row 51a and the semiconductor IC 5
When connecting to each digital signal terminal 5a,
9 can be wired linearly, and the wiring length can be further reduced.

The ground terminal row 51b is made of a metal ball similar to the digital signal terminal row 51a, and this metal ball becomes a terminal of the ground terminal row 51b. Ground terminal row 51b
Are provided so as to face each other in the vicinity thereof while maintaining a predetermined interval for each terminal of the digital signal terminal row 51a, and are connected to a digital ground. Further, each terminal of the ground terminal row 51b is connected to the opposing digital signal terminal row 5
The terminals 1a are arranged so as to be positioned on the semiconductor IC 5 side.

The other inter-substrate connecting portions 42 and 43 have the same configuration as the inter-substrate connecting portion 41. The board-to-board ground connection portion 55 is made of the same metal sphere as the ground terminal rows 51b, 52b, and 53c. The board-to-board ground connection 55
It is provided at four corners of the multilayer circuit board 11 between the multilayer circuit board 11 and the double-sided circuit board 13, and connects the digital ground of the multilayer circuit board 11 to the digital ground of the double-sided circuit board 13.

By forming the means for connecting the multilayer circuit board 11 and the double-sided circuit board 13 with conductive metal spheres, the distance between the boards can be reduced as compared with the case of using the connector as in the first embodiment. The length of the connecting means can be greatly reduced. That is, the digital signal terminal row 51a,
52a, 53a and ground terminal rows 51b, 52b, 5
3b can be reduced in terminal pitch. Thus, the inter-substrate wiring 19 can be wired more linearly, and the occurrence of unnecessary radiation noise can be further suppressed.

Further, since the reflow process can be used for arranging the board connecting portions 51, 52 and 53, the cost per terminal can be made lower than that of the connector.

The board-to-board ground connection portion 55 as a dummy ground terminal is connected to the double-sided circuit board 13 and the multilayer circuit board 1.
1, the digital ground of the multilayer circuit board 11 is strengthened, and the generation of unnecessary radiation noise can be further suppressed.

(Embodiment 3) FIG. 6 is a schematic configuration diagram showing Embodiment 3 of the present invention, and FIG.
It is the schematic sectional drawing cut | disconnected along the line. 6 and 7
, The same reference numerals as in the first and second embodiments are the same.

As shown in FIGS. 6 and 7, the digital circuit board 60 of this embodiment is basically the same as that of the second embodiment.
The digital ground plane 13 is provided on a part of the surface circuit surface 13a of the double-sided circuit board facing the multilayer circuit board 11,
The difference is that b is formed and the ground connection portion 65 between the substrates is provided. In FIG. 6, the board connecting portions 51, 52, 53 and the board-to-board ground connecting portion 65 are drawn on both the multilayer circuit board 11 and the double-sided circuit board 13, but this is for convenience of explanation. Actually, it is a component provided between the multilayer circuit board 11 and the double-sided circuit board 13.

Hereinafter, differences from the second embodiment will be described in detail. The digital circuit board 60 according to the present embodiment includes the semiconductor ICs 1 and 3 and the digital grounds of the multilayer circuit board 11 and the double-sided circuit board 13 and the semiconductor ICs 1 and 3.
Is shielded by a means for connecting a digital ground provided so as to surround the signal, thereby reducing the generation of unnecessary radiation noise.

As shown in FIGS. 6 and 7, the multilayer circuit board 11
Are mounted on the surface circuit surface 11 b of the multilayer circuit board 11 facing the double-sided circuit board 13. On the double-sided circuit board 13, a digital ground plane 13b which is a wide digital ground is formed on a part of one surface circuit plane 13a facing the multilayer circuit board 11. That is, the semiconductor ICs 1 and 3 are arranged between the digital ground of the multilayer circuit board and the digital ground plane 13b.

The board-to-board ground connection portion 65 is a row made of metal balls having the same conductivity as the ground terminal rows 51b, 52b, 53b, and is provided between the multilayer circuit board 11 and the double-sided circuit board 13. The inter-substrate ground connection portion 65 includes the ground terminal rows 51b, 52b, and 53b in a part thereof, and is provided continuously so as to surround the semiconductor ICs 1 and 3. The board-to-board ground connection portion 65 is the same as that shown in FIG.
The digital ground plane 13b formed on the double-sided circuit board 13 and the digital ground of the multilayer circuit board 11 are connected as shown in FIG.

As described above, the semiconductor ICs 1 and 3 are connected to the digital ground of the multilayer circuit board 11 and the digital ground plane 1.
3b, and the inter-substrate ground connection portion 65 connected to the digital ground and the digital ground surface 13b so as to surround the electronic components such as the semiconductor ICs 1, 3 and the like. It is shielded by the ground plane 13b and the digital ground of the multilayer circuit board 11, and as a result, it is possible to suppress the emission of unnecessary radiation noise.

In the digital circuit board 60, the diameter of the metal sphere used for the board-to-board connection portions 51, 52, 53 may be larger than that of the second embodiment. this is,
This is to increase the distance between the multilayer circuit board 11 and the double-sided circuit board 13 and increase the heat radiation effect. The diameter of the metal sphere used here is preferably about 4 to 7 mm, but is not limited thereto.

Further, as shown in FIG. 8, a sheet 21a for connecting the semiconductor IC 1 and the digital ground plane 13b is provided between the semiconductor IC 1 and the digital ground plane 13b.
A sheet 21b for connecting the semiconductor IC 3 to the digital ground plane 13b may be provided between the semiconductor IC 3 and the digital ground plane 13b. In the configuration shown in FIGS. 6 and 7, the semiconductor ICs 1 and 3 exist in a narrow space surrounded by the board-to-board ground connection portion 65, the digital ground plane 13b, and the multilayer circuit board 11. If the semiconductor ICs 1 and 3 that emit radiant heat are arranged in such a narrow space, heat may be trapped in this space and the semiconductor ICs 1 and 3 may be damaged. To cope with such a phenomenon,
Further, sheets 21a and 21b made of a heat conductive material are provided. As a result, the semiconductor ICs 1 and 3 are
The direct contact with the digital ground plane 13b via 21b makes it possible to more efficiently dissipate the radiant heat generated from the semiconductor ICs 1 and 3.

(Embodiment 4) FIG. 9 is a schematic configuration diagram showing Embodiment 4 of the present invention, and FIG. 10 is a schematic sectional view taken along line CC in FIG. In addition,
9 and 10, the same reference numerals as in the third embodiment denote the same components.

As shown in FIGS. 9 and 10, a digital circuit board 70 of the present invention is basically the same as that of the third embodiment, but a semiconductor IC is mounted on a different circuit surface of a multilayer circuit board.
1 and 3 are different from the third embodiment in that a metal box 23 is provided in addition to the configuration of the third embodiment. Note that FIG.
, The board connecting portions 51, 52, 53 and the board-to-board ground connecting portion 65 are connected to the multilayer circuit board 11 and the double-sided circuit board 13
However, this is for convenience of explanation, and is actually one component provided between the multilayer circuit board 11 and the double-sided circuit board 13.

Hereinafter, differences from the third embodiment will be described in detail. The digital circuit board 70 according to the present embodiment includes a means for connecting the digital grounds of the multilayer circuit board 11 and the double-sided circuit board 13 to the digital ground provided so as to surround the semiconductor ICs 1 and 3;
A semiconductor IC with a metal box provided to cover C1 and C3
By shielding 1 and 3, the occurrence of unnecessary radiation noise is reduced.

As shown in FIGS. 9 and 10, the double-sided circuit board 1
3 and the one surface circuit surface of the multilayer circuit board 11 facing 1
1b and the other surface circuit surface 11a, the semiconductor ICs 1, 3 provided on the multilayer circuit board 11 have the surface circuit surface mounted on 11a.

The metal box 23 is a metal box provided so as to cover the surface circuit surface 11a, and is connected to the digital ground of the multilayer circuit board 11.

As described above, the metal box 23 is provided so as to cover the surface circuit surface 11a on which the semiconductor ICs 1 and 3 are arranged.
Unnecessary radiation noise generated from C1 and C3 can be suppressed.

Further, the metal box 23 is connected to the digital ground of the multilayer circuit board 11. Therefore, metal box 2
3 is an inter-substrate ground connection portion 6 comprising a large number of connection terminals.
5 and connected to the digital ground plane 13b. As a result, the shielding effect of the metal box 23 is further improved, and the occurrence of unnecessary radiation noise can be reduced.

(Embodiment 5) FIG. 11 is a schematic configuration diagram showing Embodiment 5 of the present invention, and FIG.
It is the schematic sectional drawing cut | disconnected along the -D line. FIG.
In the first and twelfth embodiments, the same components as those in the third embodiment are denoted by the same reference numerals.

As shown in FIGS. 11 and 12, a digital circuit board 80 of the present invention is basically the same as that of the second embodiment, but a semiconductor IC is mounted on a different circuit surface of a multilayer circuit board.
1 and 3 are different in that ground terminal rows 51 a having different terminal arrangements are provided in the board-to-board connection portion 51. Note that, in FIG.
1, 52 and 53 are a multilayer wiring board 11 and a double-sided wiring board 13
However, this is for convenience of explanation, and is actually one component provided between the multilayer wiring board 11 and the double-sided wiring board 13.

Hereinafter, differences from the second embodiment will be described in detail. The digital circuit board 80 according to the present embodiment includes the ground terminal rows 51b, 52b, so as to surround the digital signal terminals 51a, 52a, 53a, respectively.
By arranging 53b, unnecessary radiation noise generated in the means for connecting the substrates is reduced.

For example, in the second embodiment, each terminal of the ground terminal row 51b is arranged in a row so as to substantially face each terminal of the digital signal terminal row 51a. On the other hand, in the present embodiment, each terminal of the ground terminal row 51b is continuously arranged so as to surround the digital signal terminal row 51a as shown in FIG. That is, the ground terminal row 51b in the present embodiment is replaced by the second embodiment.
, The metal balls are arranged continuously in a row of the metal balls arranged in a line so as to surround the digital signal terminal row 51a. In addition, other inter-substrate connection parts 52 and 53
Also has the same configuration as the inter-substrate connection unit 51.

As described above, the ground terminal rows 51b, 52
b, 53b are replaced with digital signal terminal rows 51a, 52a, 5
3a is provided continuously so as to individually surround each of the digital signal terminal arrays 51a, 51a,
Unnecessary radiation noise generated in 2a and 53a is absorbed by the ground terminal rows 51b, 52b and 53b, and as a result, unnecessary radiation noise can be reduced.

[0084]

According to the digital circuit board of the present invention, at least a cross wiring cannot be avoided in connecting a first circuit board on which at least one integrated circuit is mounted and an integrated circuit mounted on the first circuit board. It is divided into four or more layers of a second circuit board on which one integrated circuit is mounted, and all the cross wirings are formed on the second circuit board. Each of the first circuit board and the second circuit board includes a plurality of signal terminals and at least a ground terminal disposed in the vicinity of each of the signal terminals. Each of the integrated circuit mounted on the first circuit board has The first and second circuit boards are connected via an inter-board connection portion provided between the first and second circuit boards. This makes it possible to suppress the generation of unnecessary radiation noise by performing the cross wiring only on the multilayer circuit board.

The plurality of signal terminals of the board-to-board connection portion are arranged in a row so as to substantially face the signal terminals of the integrated circuit mounted on the first circuit board having the signal terminals arranged in a predetermined arrangement order. You. The signal terminal thus configured is
It is provided for each integrated circuit mounted on the first circuit board.
Each signal terminal of the integrated circuit mounted on the first circuit board;
The respective terminals of the signal terminals of the inter-substrate connection portion provided in correspondence with this are connected without crossing. This allows
The digital wiring of the first circuit board can be arranged short and without crossover wiring.

The ground terminals are arranged so as to face each other in the vicinity of each signal terminal. Further, the plurality of ground terminals are arranged such that the plurality of signal terminals are positioned on the side of the integrated circuit mounted on the first circuit board. The plurality of ground terminals arranged in this manner serve as digital grounds for opposing signal terminals, and can reduce radiation noise that has conventionally occurred at the connection between the first circuit board and the second circuit board. It becomes possible.

With the digital circuit board of the present invention configured as described above, even when a digital circuit including a multi-terminal and narrow-pitch semiconductor IC occupies most of the board, the cost increases and the unnecessary radiation noise characteristic deteriorates. Can be prevented.

Further, the digital circuit board of the present invention has an effect that it can be applied to any digital electronic equipment that requires a digital circuit such as a television and a video.

[Brief description of the drawings]

FIG. 1 is a schematic structural diagram illustrating a digital circuit board according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a connection portion between substrates according to the first embodiment of the present invention.

FIG. 3 is a schematic structural diagram showing a digital circuit board according to a second embodiment of the present invention.

FIG. 4 is an enlarged view of a connection portion between substrates according to a second embodiment of the present invention.

FIG. 5 is a schematic cross section showing the digital circuit board taken along line AA in FIG. 3;

FIG. 6 is a schematic structural diagram showing a digital circuit board according to a third embodiment of the present invention.

FIG. 7 is a schematic sectional view showing the digital circuit board taken along the line BB in FIG. 6;

FIG. 8 is a schematic cross-section showing another configuration of the digital circuit board taken along the line BB in FIG. 6;

FIG. 9 is a schematic structural diagram showing a digital circuit board according to a fourth embodiment of the present invention.

FIG. 10 is a schematic cross section showing the digital circuit board taken along the line CC in FIG. 9;

FIG. 11 is a schematic structural diagram showing a digital circuit board according to a fifth embodiment of the present invention.

FIG. 12 is a schematic cross section showing the digital circuit board taken along the line DD in FIG. 11;

FIG. 13 is a schematic structural view showing a conventional digital circuit board.

FIG. 14 is a structural diagram showing a study example of a digital circuit board before the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Semiconductor IC 1a Signal terminal 2 Semiconductor IC connection wiring 3 Semiconductor IC 5 Semiconductor IC 5a Signal terminal 7 Semiconductor IC 8 Semiconductor IC connection wiring 9 Semiconductor IC 10, 50, 60, 70, 80 Digital circuit board 11 Multilayer circuit board 11a, 11b Surface circuit surface 13 Double-sided circuit board 13a Circuit surface 13b Digital ground plane 17 First inter-board wiring 19 Second inter-board wiring 21 Conductive and heat conductive sheet 23 Conductive metal box 41, 42, 43 Connector 41a, 42a, 43a, 51a, 52a, 53a, 8
1a, 82a, 83a Digital signal terminal row 41b, 42b, 43b, 51b, 52b, 53b, 8
1b, 82b, 83b Ground terminal row 51, 52, 53, 81, 82, 83 Board-to-board connection 55, 65 Board-to-board ground connection

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Koichiro Nagata 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 72) Inventor Hideyuki Kawashima 1006 Kazuma, Kadoma, Osaka Pref.F-term in Matsushita Electric Industrial Co., Ltd. (Reference)

Claims (14)

[Claims] 1. A connection between a first circuit board on which at least one integrated circuit having a plurality of signal terminals is mounted and an integrated circuit mounted on the first circuit board, at least cross wiring is inevitable. A second circuit board on which one integrated circuit is mounted; and a board-to-board connection section for electrically connecting the first circuit board and the second circuit board. A plurality of integrated circuits are provided between the first circuit board and the second circuit board so as to face each integrated circuit mounted on the first circuit board, and transmit the predetermined signal. A signal terminal; a plurality of ground terminals provided at least in the vicinity of each of the signal terminals and connected to a ground for providing a reference potential; each signal terminal of the integrated circuit mounted on the first circuit board; A board corresponding to the integrated circuit Low EMI digital circuit board each wiring is characterized in that it is arranged so as not to cross connecting the signal terminals between connections. 2. The low EMI digital circuit board according to claim 1, wherein a connector is used for the board-to-board connection part. 3. The low EMI digital circuit board according to claim 1, wherein each of the signal terminals and each of the ground terminals of the board-to-board connection portion are formed of conductive metal balls. 4. The low EMI according to claim 3, wherein the metal sphere is brazed to the first circuit board and the second circuit board via a conductive metal. Digital circuit board. 5. The low EMI digital circuit board according to claim 1, wherein a flat cable with a shield is used for the board-to-board connection part. 6. The low EMI digital circuit board according to claim 1, wherein the first circuit board is a double-sided circuit board. 7. The low EMI digital circuit board according to claim 1, wherein the first circuit board is a multilayer circuit board having four or more layers. 8. The low EMI digital circuit board according to claim 1, wherein the second circuit board is a multilayer circuit board having four or more layers. 9. A conductive metal box provided so as to cover at least an integrated circuit mounted on the first circuit board, and electrically connected to a plurality of ground terminals of the inter-board connection portion. The low EMI digital circuit board according to claim 3, wherein: 10. An integrated circuit mounted on the second circuit board is provided between the integrated circuit and the first circuit board, and
4. The low EMI digital circuit board according to claim 3, wherein a plurality of ground terminals of the board-to-board connection are continuously arranged so as to surround the integrated circuit. 11. The device according to claim 3, wherein the plurality of ground terminals of the inter-substrate connection are continuously arranged so as to surround the plurality of signal terminals of the inter-substrate connection. Low EMI digital circuit board. 12. The low EMI according to claim 1, further comprising a conductive and heat conductive sheet provided on an integrated circuit mounted on the second circuit board and connected to the ground. Digital circuit board. 13. The low EMI digital circuit board according to claim 1, wherein the second circuit board is a chip size package. 14. An electronic apparatus using the low EMI digital circuit board according to claim 1.