JP2001102762A - Multilayer printed-circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a multilayer printed-circuit board, having a function for shielding electromagnetic noise being emitted from an electronic circuit that is formed at a multilayer printed-circuit board and wiring connection structure for securing connecting wiring being laminated in upper and lower directions. SOLUTION: A multilayer printed-circuit board 100 is composed by electrically, directly or indirectly connecting a closed shielding wall 111 of an electrically good conductor that is formed at an electrically good conductor layer of at least one surface of one printed-circuit board 110, by dividing a specific area to the upper end face of a closed shield wall 121 of the electrically good conductor with the same plane shape as the closed shielding wall 111, formed on the electrical good conductor layer of one surface of the other printed-circuit board 120 or the surface of the electrically good conductor layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed circuit board incorporated in an electronic device, particularly, a small and thin electronic device, and more particularly, to shielding electromagnetic noise radiated from an electronic circuit formed on the multilayer printed circuit board. Alternatively, the present invention relates to a multilayer printed circuit board having a function of shielding electromagnetic noise that jumps into the electronic circuit from the outside.

[0002]

2. Description of the Related Art First, a conventional multilayer printed circuit board will be described with reference to FIGS.

FIG. 5 shows a multilayer printed circuit board on which a shield structure according to the prior art is formed. FIG. 5A is a partial sectional view, FIG. 5B is a partial plan view, and FIG. A shows a perspective view, FIG. B shows a cross-sectional view taken along line AA of FIG. A, and FIG. 7 explains a problem of the wiring connection structure shown in FIG. FIG.

First, a multilayer printed circuit board having a conventional shield structure will be briefly described with reference to FIG. This multilayer printed circuit board 1 is disclosed in Japanese Patent Application Laid-Open No. H11-54944, and is set to a power supply potential via a first FRP board 21 on a ground layer 11 set to a ground potential. Power supply layer 1
2. The connection electrode 32 and the dummy electrode 42 are formed. The connection electrode 32 and the dummy electrode 42 are electrically connected to the ground layer 11 via the interlayer connection bump 31a and the shield bump 41, respectively. First FR
On the P substrate 21, the power supply layer 12, the connection electrode layer 32, and the dummy electrode 42, the signal wiring 1 is provided via the second FRP substrate 22.
3 are formed. Some of the wirings 13 are connected to the connection electrodes 32 via interlayer connection bumps 31b, and are electrically connected to the ground layer 11.

As described above, the multilayer printed circuit board 1 has a shield structure in which a certain area is surrounded by a plurality of shielding bumps 41.

[0006]

However, in the shield structure of the multilayer printed circuit board 1, there is a gap between the shield bumps 41, and unnecessary electromagnetic noise generated from the area or electromagnetic noise from the outside is eliminated. It cannot be completely shielded.

For interlayer connection, in addition to the shield bump 41, interlayer connection bumps 31a and 31b are used. Each interlayer connection is performed in such a manner that one bump corresponds to one wiring. Therefore, if the positions of a plurality of printed circuit boards stacked in the vertical direction are shifted, good interlayer connection cannot be performed, and the printed circuit boards stacked in the vertical direction must be precisely aligned. Must. Further, even if the alignment is performed well, the interlayer connection has a structure close to the point contact, so that the electronic circuit may be opened due to impact or the like, which hinders the improvement of reliability and yield. It has become.
Furthermore, as the integration density increases, the area of the interlayer connection of the printed circuit board decreases, the generation of Joule heat increases, the temperature of the wiring rises, and the insulating resin between the layers of the printed circuit board increases. Due to the difference in the coefficient of thermal expansion, there is a problem that disconnection is likely to occur between the wiring and the bump, and reliability is reduced.

[0008] Even if the above-mentioned misalignment of the interlayer connection slightly occurs,
As means for preventing the connection failure, there is an interlayer connection structure 50 as shown in FIG. This connection structure is based on wirings 52A, 52A formed on each printed circuit board 51A, 51B.
B has a diameter Da (for example, 300) of pads 53A and 53B, which are connection portions formed at at least one end.
μm) is formed as a circle having a diameter sufficiently larger than the diameter Db (for example, 100 μm) of the via 54 formed at the center of the pads 53A and 53B.
5, the positions of the plurality of printed circuit boards 51A and 51B stacked and bonded in the vertical direction are slightly shifted.
Even if the 2A, 52B and the pads 53A, 53B are shifted, the structure in which the pads 53A, 53B overlap each other can be maintained, and the interlayer connection can be secured.

However, the interlayer connection structure 50 having the structure shown in FIG.
As shown in FIG.
When C is formed, it must be formed at a distance from the pad 53A, so that this interlayer connection structure 50 is not suitable for a high-density integrated substrate. In particular, there is a problem that it is not suitable for application in a narrow area shielded as described above.

Accordingly, the present invention is intended to solve these problems, and has a function of shielding electromagnetic noise radiated from an electronic circuit formed on a multilayer printed circuit board, and a function of wiring vertically stacked. It is an object of the present invention to obtain a multilayer printed circuit board having a wiring connection structure capable of reliably connecting.

[0011]

Therefore, in the multilayer printed circuit board according to the first aspect of the present invention, a predetermined area is formed on the electric conductor layer on at least one surface of one printed circuit board. The closed shield wall of the electrical good conductor thus formed is replaced with an electrical good conductor layer on one surface of another printed circuit board, or a closed shield wall of an electrical good conductor having the same planar shape as the closed shield wall formed on the good electrical conductor layer. The above problem is solved by electrically connecting directly or indirectly to the upper end surface.

Further, in the multilayer printed circuit board according to the present invention, at least two printed circuit boards are vertically stacked with an insulating layer interposed therebetween, and at least one surface of one printed circuit board is stacked. A first wiring having a predetermined width and a rectangular first connection portion formed with the same width at least at one end of the first wiring are formed on the electric conductor layer, and the electric connection of at least one surface of the other printed circuit board is formed. Forming a second wiring having a rectangular second connection portion formed in a direction crossing the first connection portion on the good conductor layer in the same manner as the first wiring and the first connection portion; The first problem is solved by electrically connecting the first connection portion and the second connection portion directly or indirectly.

According to a third aspect of the present invention, there is provided a multilayer printed circuit board according to the present invention, wherein the wiring structure according to the second aspect is formed in the closed shield wall according to the first aspect. Has been resolved.

Therefore, according to the multilayer printed circuit board of the present invention, the electromagnetic noise radiated from the electronic circuit formed on the printed circuit board constituting the multilayer printed circuit board is substantially closed. Thus, the electromagnetic noise that tries to jump into the electronic circuit from the outside can be almost completely shielded.

According to the multilayer printed circuit board according to the second aspect of the present invention, it is possible to reliably perform interlayer connection of wirings formed on a plurality of printed circuit boards without taking a large area.

According to the multilayer printed circuit board of the present invention, even in a narrow area which is surrounded by a closed shield wall and is electromagnetically shielded, high-density wiring is performed in the narrow area. Can be.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a multilayer printed circuit board according to a preferred embodiment of the present invention.

FIG. 1 is a perspective view of a printed circuit board having a closed shield wall according to an embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view of a multilayer printed circuit board according to an embodiment of the present invention having a structure in which two printed circuit boards are stacked and a shield is formed inside, and FIG. 3 shows a wiring connection structure according to an embodiment of the present invention. A is a perspective view, FIG. B is a cross-sectional view taken along line AA of FIG. A, and FIG. 4 is the same as FIG. 3B for explaining the advantages of the wiring connection structure shown in FIG. FIG.

First, a printed circuit board having a closed shield wall according to an embodiment of the present invention will be described with reference to FIG.

In FIG. 1, reference numeral 110 denotes a printed circuit board which is one of the components of the multilayer printed circuit board 100 according to one embodiment of the present invention. A closed shield wall 111 is formed on an electric conductor layer on one surface of the printed circuit board 110 by utilizing photolithography technology and electroplating technology. In the case shown, this closed shield wall 11
1 is formed in a rectangular square shape. The wiring 112 is connected and formed on one short side of the closed shield wall 111, for example.

Similarly, as shown in FIG. 2, a closed shield wall 121 having the same shape and size as the closed shield wall 111 is also formed on an electric conductor layer on one surface of another printed circuit board 120. And both printed circuit boards 11
0 and 120 are laminated together with the closed shield walls 111 and 121. Thus, both closed shield walls 111,
121 are combined to form a shielded area 130 which is a closed space inside. In the example shown in FIG. 2, the printed circuit board 110 shown in FIG. 1 is turned upside down and put on the closed shield wall 121 of the printed circuit board 120, united, and electrically connected directly. Both printed circuit boards 110 are electrically insulated and adhesive resin 140,
The multilayer printed circuit board 100 has a structure in which the substrate 120 is bonded. The closed shield walls 111 and 121 are made of Cu, N
It can be formed of i, Sn, Au, Ag, or the like.

In the example shown in FIG. 2, the closed shield wall 121 is also formed on the printed circuit board 120 and the shielded area 130 is formed, but the closed shield wall 121 is formed on the printed circuit board 120 side. Is not formed, the electric conductor layer on the surface is directly laminated as a lid of the closed shield wall 111, and the shielded area 130
(Not shown).

The shielded area 130 is usually small in area. A wiring connection structure suitable for forming a large number of wirings at high density in the shielded area 130 having a small area will be described below with reference to FIG.

In FIG. 3, reference numeral 200 denotes one wiring 2
10 shows a connection structure in a multilayer printed circuit board in a state where the other wiring 220 is crossed and electrically connected. At least one end of each of the wirings 210 and 220 has a width substantially equal to the width of the wirings 210 and 220, a length of, for example, four times the width, and a thickness of the wirings 210 and 220.
Of the rectangular parallelepiped are formed slightly thicker than the thickness of the rectangular parallelepiped.

By forming such wirings 210 and 220, when connecting and connecting the connecting portions 211 and 221 so as to cross each other, the connection position between them is four times as long as that described above. The two connecting portions 21
1 and 221 remain on the connection part of each other,
It is possible to prevent poor connection as seen in the prior art, and furthermore, since both connecting portions 211 and 221 are in contact with each other, it is possible to make a reliable connection and to suppress the generation of Joule heat at the connecting portion between them. be able to.

Therefore, the wiring 2 as described above is attached to the printed circuit boards 110 and 120 in the shielded area 130.
10, 220 and the connecting portion 211,
221 is formed and wired, and as shown in FIG. 3B, the two printed circuit boards 110 and 120 are connected to the electrically insulating adhesive resin 1.
By bonding and bonding such that the connection structure 200 is formed through the connection 40, a multilayer printed circuit board can be obtained. In addition, as shown in FIG.
0, 220 can be formed.

It should be noted that the formation of the wiring connection structure 200 of the present invention is not limited to the inside of the shielded area 130 but can be applied to the area outside the shielded area 130 as well.

In each of the above embodiments, the printed circuit boards 110 and 120 have two layers. However, the present invention is not limited to a two-layer printed circuit board. It is to be noted that the present invention can be applied to a multilayer printed circuit board described above.

[0029]

As described above, according to the multilayer printed circuit board of the present invention, since the shield portion can be hermetically sealed, electromagnetic noise can be almost completely shielded.

Further, since the connection portion of the wiring is formed with a width equal to the width of the wiring, high-density integration is possible. Further, since the connection structure of the wiring is in surface contact and the connection portion is rectangular, the connection can be surely made even if the connection position is slightly shifted.

[Brief description of the drawings]

FIG. 1 is a perspective view of a printed circuit board having a closed shield wall according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a multilayer printed circuit board according to an embodiment of the present invention having a structure in which two printed circuit boards shown in FIG. 1 are stacked to form a shield inside.

3A and 3B show a wiring connection structure according to an embodiment of the present invention. FIG. A is a perspective view thereof, and FIG. 3B is a cross-sectional view taken along line AA of FIG.

FIG. 4 is a cross-sectional view similar to FIG. 3B for explaining advantages of the wiring connection structure shown in FIG. 3;

5A and 5B show a multilayer printed circuit board on which a conventional shield structure is formed, FIG. 5A is a partial cross-sectional view, and FIG. 5B is a partial plan view.

6A and 6B show a conventional one-wire connection structure, and FIG. 6A is a perspective view thereof, and FIG. 6B is a cross-sectional view taken along line AA of FIG. 6A.

7 is a cross-sectional view for describing a problem of the wiring connection structure shown in FIG.

[Explanation of symbols]

100 Multilayer printed circuit board according to one embodiment of the present invention;
110, 120 ... printed circuit board, 111, 121 ...
Closed shield wall, 112: wiring, 130: shielded area, 140: electrically insulating adhesive resin, 200: wiring structure of one embodiment of the present invention, 210, 220: wiring, 21
1,221 ... connection part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor, Masayuki Yasuda 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Yuji Nishitani 6-35, 7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony F term in reference (reference) 5E321 AA17 BB23 BB24 GG05 5E338 AA03 BB25 BB61 CC05 CD01 EE13 5E346 BB07 BB20 DD22 DD44 FF24 GG17 GG18 HH01 HH07

Claims (3)

[Claims] 1. An electric conductor layer formed on an electric conductor layer on at least one surface of one printed circuit board by separating a predetermined area from the electric conductor layer and having a closed shield wall of the electric conductor layer on one surface of another printed circuit board. Alternatively, the closed shield wall formed in the electrical good conductor layer is electrically directly on the upper end surface of the closed shield wall of the same good electrical conductor as the planar shape,
Or a multilayer printed circuit board characterized by being connected indirectly. At least two printed circuit boards are vertically stacked with an insulating layer interposed therebetween. A first wiring having a predetermined width and a first wiring having a predetermined width are provided on at least one surface of the printed circuit board. A rectangular first connection portion having the same width is formed at at least one end of one wiring, and an electric good conductor layer on at least one surface of the other printed circuit board,
A second wire having a rectangular second connection portion formed in a direction intersecting with the first connection portion is formed in the same manner as the first wire and the first connection portion. The second
A multilayer printed circuit board, wherein the connection portion is electrically connected directly or indirectly. 3. The closed shield wall according to claim 1, wherein:
A multilayer printed circuit board, wherein the wiring structure according to claim 2 is formed.