JPH05291787A - Multilayer wiring board for high frequency and its manufacture - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a high-frequency multilayer wiring board which has an excellent shield effect and can be sufficiently thinned, and a manufacturing method thereof. In a high frequency multilayer wiring board, a shield layer is provided on the upper and lower surfaces and both left and right end surfaces of the multilayer wiring board having a predetermined shape formed by laminating inner layer wiring boards. In the manufacturing method, a multilayer wiring board base material formed by laminating the base material of the inner layer wiring board is subjected to a cutting process to expose the left and right end surfaces of the shielded multilayer wiring board, and then the shield layer. Is formed by plating, and then punching into a predetermined shape is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency multilayer wiring board used for wiring a computer, a communication device, etc., and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a high frequency multilayer wiring board used for wiring a computer, a communication device, etc., (a) and (b) of FIG. 4 (a cross-sectional view taken along the line of (a) of FIG. 4). As shown in FIG. 1, an inner wiring board 1 '(a printed circuit board 12' with conductors 12 'of a predetermined circuit pattern printed on one or both sides) is laminated, and a shield layer 3 of metal foil is formed on the upper and lower surfaces thereof. ', And the grounding conductor 121 present on both width ends of each inner layer wiring board'
To the shield layer 5'with predetermined intervals of the sulfur 5 ',.
To form a hole 22 'through which the conductor terminal 13' penetrates and the terminal hole 22 'and the shield layer end 31' are separated by a predetermined insulation distance. Patterning is performed to cover the shield layer with a resin layer (not shown).

[0003]

However, in the above high frequency inner layer wiring board, since the grounding conductors of the respective inner layer wiring boards are connected to the shield layer by the sulfur provided at predetermined intervals, Resonance occurs due to the pitch of the sulfol, and for example, when the pitch is 2 cm, it is difficult to remove noise of 4 GHz or more.

Further, a laminate film of a metal foil and a plastic film is heated and pressed on the upper and lower surfaces of the inner wiring board laminate to form a shield layer, and a laminate film is used for thinning the laminate film. Since there is an upper limit of handling of the tape, there is a limitation in thinning the multilayer wiring board.

An object of the present invention is to eliminate such a problem, and to provide a high-frequency multilayer wiring board which has an excellent shield effect and can be sufficiently thinned, and a manufacturing method thereof.

[0006]

According to the present invention, there is provided a high-frequency multilayer wiring board, wherein a shield layer is provided on a multilayer wiring board having a predetermined shape formed by laminating inner layer wiring boards, and upper and lower surfaces and left and right ends of the multilayer wiring board. It is characterized in that it is provided over the surface, and the grounding conductor of each inner layer wiring board can be electrically contacted with the left and right end surfaces of the shield layer.

A method of manufacturing a high frequency multilayer wiring board according to the present invention is a method of manufacturing the above high frequency multilayer wiring board,
The multilayer wiring board base material formed by laminating the base material of the inner layer wiring board is subjected to a cutting process for exposing the shielded left and right end surfaces of the high-frequency multilayer wiring board, and then a shield layer is provided by plating. After that, the structure is characterized by punching into a predetermined shape.

[0008]

[Function] The shield layer is provided not only on the upper and lower surfaces of the multilayer wiring board but also on both left and right end surfaces, and the wiring conductor is completely surrounded by the shield layer, so that an excellent shield effect is achieved. it can. Also, since the shield is provided by plating, the shield layer can be made thinner than when using a metal foil,
The overall thickness of the high-frequency multilayer wiring board can be reduced accordingly.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a perspective explanatory view showing an embodiment of the high frequency multilayer wiring board of the present invention, and FIG. 1B is a cross-sectional view taken along the line RO in FIG. In FIG. 1A and FIG. 1B, 1 is an inner wiring board, and an insulating substrate 11
A conductor 12 (signal line) of a predetermined circuit pattern is printed on one side or both sides of. The inner wiring board 1 has header parts at both ends, and conductor terminals 13 are provided on the header parts. Reference numeral 2 denotes a multilayer wiring board. The inner wiring board 1 is laminated and adhered with an adhesive, and the upper and lower surfaces of this laminated body are covered with a cover insulating material 21 (in the case of a single-sided printed board, only one side is covered). Covered with insulating material for the cover). Reference numeral 22 denotes a hole formed in the multilayer wiring board 2 from above the insulating material 21 for the cover and penetrating the conductor terminal 13.

Numeral 3 is a shield layer provided on the upper and lower surfaces of the multilayer wiring board 2 and on both left and right end surfaces, and the shield layer end 31 and the terminal hole 22 are separated by a predetermined insulating distance. Further, as shown in FIG. 1B, the grounding conductors 121 at both ends of the width of the inner layer wiring board are electrically contacted with the left and right end surface portions of the shield layer 3.

In FIG. 1A, 32 is a terminal of the shield layer, which is present on the insulating material 21 for the cover.
In FIG. 1B, 4 is an insulating material coated on the shield layer 3 and is not shown in FIG.

The insulating substrate 11 of the inner layer wiring board 1 is made of, for example, glass epoxy, various polyimides, epoxy resin, polyethylene terephthalate, resin-impregnated synthetic paper, phenol resin, fluorine resin, or these materials. A composite material, a material containing an appropriate filler, or the like is used, and the thickness is 2 μm to 2000 μm, preferably 5 μm to 800 μm.
m. Further, as the conductor material 11, for example, copper, aluminum, 42 nickel alloy or the like is used, and various metals (nickel, gold, tin, solder, solder,
Palladium alloy etc.) is plated.

The shield layer 3 is formed by electroless plating, and its plating material is, for example, copper, tin,
Gold, solder, etc. are used.

As the insulating material 21 for the cover, epoxy resin, polyester resin, various polyimide resins, polyurethane, various polyamides, acrylic resins, fluororesins, films of these, or inorganic fillers are used.
Can be used, or these composite materials can be used,
The thickness is 1 μm to 1000 μm, preferably 5 μm to 3
00 μm.

In order to manufacture the above high frequency multilayer wiring board by the method of the present invention, first, a copper foil laminated insulating substrate (for example, a polyimide film having a thickness of 50 μm is used as the insulating substrate, and the copper foil has a thickness of 35 μm). The copper foil of (1) is chemically etched into a predetermined circuit pattern to obtain a base material for the inner layer wiring board, the inner layer wiring board base material is laminated and adhered, and the insulating film for the cover is adhered with an adhesive. Then, a hole is drilled in the terminal portion by the NC method to obtain a multilayer wiring board base material.

FIG. 2A shows the multilayer wiring board substrate A thus obtained, the upper surface of which is the insulating film 21 for the cover.
The conductor immediately below the film 21 is indicated by a broken line.

When the multilayer wiring board base material A is obtained as described above, a portion of the outer surface of the multilayer wiring board base material where the shield layer is not plated [shield terminal in (a) of FIG. 1]. 32
Including the above], a plating resist is printed by a screen printing machine, and after this printing, portions corresponding to both sides of the shielded portion of the multilayer wiring board shown in FIG. As shown in FIG. 2B, the left and right end surfaces b, b of the shield in the multilayer wiring board are exposed, and the whole is immersed in a plating activation treatment bath to perform the plating activation treatment.

Next, the plating resist coating is removed by immersion in a weak alkaline solution, and further electrolessly plated with copper by immersion in an electroless plating bath (for example, its thickness is 5
After that, an insulating film for a cover is attached to the upper and lower surfaces of the multilayer wiring board base material with an adhesive, and finally the multilayer wiring board base material is punched into a high-frequency multilayer wiring board of a predetermined shape. This completes the fabrication of the high frequency multilayer wiring board.

For the incision of the portions corresponding to both sides of the shielded portion of the multilayer wiring board, punching with a die, cutting with a router, cutting with a laser or the like can be used. In the above, the coating of the plating activator, which is performed after cutting the portions corresponding to both sides of the shielded portion of the multilayer wiring board, is performed by the screen printing device (with the total length of the cutting edge b in FIG. 2B). The printing width is 1m against the width W so that the end face of
It is also possible to omit the printing of the plating resist.

In the present invention, a double-sided printed wiring board can be used for the inner layer wiring board, and the insulating material for the cover immediately below the shield layer is coated on one side with a resin mixed with a plating active species. It is also possible to use the above-mentioned insulating film, and furthermore, as shown in FIG. 3, the shield layer 4 can be provided on the entire surface of the headers at both ends except the terminal surrounding opening c.

To manufacture such a high-frequency multilayer wiring board according to the present invention, first, an inner layer wiring board base material is obtained by chemically etching double-sided copper foil of a double-sided copper foil laminated insulating substrate, and the inner layer wiring board substrate is laminated.・ Adhere. On the other hand, an adhesive film is applied to one surface of the plastic film, and an insulating film for a cover in which a plating active species mixed resin is printed on the other surface by a flat pattern of a shield layer having a terminal surrounding opening c shown in FIG. obtain. Next, the insulating film for a cover is adhered to the laminate of the inner wiring board base material with an adhesive layer, and a hole penetrating the conductor terminal hole is formed.

Further, a mask resist is printed in a ring shape around the perforated terminal hole by a screen printing machine, and further, portions corresponding to both sides of the shielded portion of the multilayer wiring board are formed. Make an incision and cut the shield on the multilayer wiring board.
Both the left and right end surfaces of the solder are exposed, then immersed in a plating activation bath, and further electrolessly plated with copper by immersion in an electroless plating bath to provide a shield layer.

After removing the resist with a weak alkaline solution, an insulating resin is applied to the upper and lower surfaces of the shield layer one by one with a screen printer, and soldered to the terminals with a roll soldering device. Is applied and punched into a predetermined shape of the high-frequency multilayer wiring board with a die, thereby completing the production of the high-frequency multilayer wiring board.

In the fabrication of this high-frequency multilayer wiring board, a plating active species mixed resin is printed on one surface of the insulating film for the cover by a flat pattern of the shield layer having the terminal surrounding openings shown in the figure. However, the plating active species mixed resin is applied to the entire one surface of the insulating film for the cover, and after the electroless plating, the terminal surrounding opening is chemically etched in the plating layer,
It is also possible to form a hole penetrating the terminal hole on the exposed surface of the insulating film for a cover in the opening.

[0025]

The multi-layer wiring board for high frequencies of the present invention is constructed as described above, and shield layers are provided on the upper and lower surfaces and left and right end surfaces of the multi-layer wiring board, and the grounding conductor of each inner wiring board is left and right. Since it is electrically conducted to the shield layers on both end faces, all wiring conductors can be completely surrounded by the shield layer, and the grounding conductor can be electrically contacted with the shield layer over the entire length. , You can guarantee the excellent shield effect.

Further, in the method for manufacturing a high frequency multilayer wiring board according to the present invention, since the shield layer is formed by plating and the use of the metal foil is excluded, the shield layer is sufficiently thin. It is possible to reduce the total thickness of the high frequency multilayer wiring board.

[Brief description of drawings]

FIG. 1A is a perspective explanatory view showing a high-frequency multilayer wiring board of the present invention, and FIG. 1B is an explanatory sectional view taken along line B-B in FIG.

FIG. 2 is an explanatory view showing a main part in a method of manufacturing a high frequency multilayer wiring board according to the present invention.

FIG. 3 is an explanatory plan view showing another example of the shield layer pattern of the high-frequency multilayer wiring board of the present invention.

4 (A) is a perspective explanatory view showing a conventional high-frequency multilayer wiring board, and FIG. 4 (B) is a cross-sectional explanatory view taken along the line of FIG. 4 (A).

[Explanation of symbols]

 1 inner layer wiring board 2 multilayer wiring board 121 grounding conductor 3 shield layer b shielded left and right end surfaces

Claims (3)

[Claims] 1. A multi-layer wiring board for high frequencies, characterized in that a shield layer is provided on a multi-layer wiring board having a predetermined shape formed by laminating inner layer wiring boards, over the upper and lower surfaces and both left and right end surfaces of the multi-layer wiring board. .. 2. A high-frequency multilayer wiring board according to claim 1, wherein the grounding conductor of each inner wiring board is electrically contacted with the left and right end surfaces of the shield layer. 3. A multilayer wiring board base material obtained by laminating base materials of an inner layer wiring board is subjected to a cutting process for exposing left and right end surfaces of a shield in a high frequency multilayer wiring board, and then a shield layer. Is provided by plating, and then punching into a predetermined shape is performed, which is a method for producing a high-frequency multilayer wiring board.