JPH0537094A - Printed wiring board - Google Patents

Abstract

PURPOSE:To prevent moisture absorption and resin dust from an end face by providing the full periphery of an outer shape end face or a part of an end face with a conductor, and also preferably the front and the rear of a printed wiring board adjacent to the end face part provided with the conductor with a conductor with an arbitrary width in continuity to the conductor provided on the end face. CONSTITUTION:A conductor 16 is formed over the full periphery or a part of an outer shape end face 15 of a printed wiring board 10. Or in continuity to the conductor 16 provided on the end face 15, a conductor 18 is formed with an arbitrary width on the front and the rear of the printed wiring board 10 adjacent to the end face part provided with the conductor 16. This process can prevent dust of epoxy resin and moisture absorption from an end face and improve shield characteristics and heat dissipation characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board structure. The development of the electronics industry in recent years has been remarkable, and as a thing that has supported this development, technologies such as multifunctionalization of electronic parts such as semiconductors, high performance, high integration, miniaturization, cost reduction, etc. Can make progress.

With the technical progress of such electronic parts,
There is a demand for high density, thinness, high thermal conductivity and high quality of printed wiring boards. Recently, this tendency has been further accelerated especially with the advent of surface mounting technology.

[0003]

2. Description of the Related Art Manufacturing methods of printed wiring boards with through holes are roughly classified into a subtractive method, a full additive method and a partial additive method. In general, in addition to the conductor pattern of the surface layer and the conductor pattern of the inner layer, the land portion of the conductor is formed on the front and back sides of the printed wiring board around the through hole or via hole. No conductor is formed on the.

[0004]

Since the conventional printed wiring board is not provided with a conductor on the end face of the outer shape, there is a problem that dust such as epoxy resin is generated from the end face of the outer shape or moisture is easily absorbed from the end face. It was Further, the printed wiring board is heated by the heat generated by the mounted electronic components, but it is currently difficult to efficiently dissipate this heat.
For example, a metal core printed wiring board has good heat dissipation characteristics but is expensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to form a conductor on the end face of the outer shape of a printed wiring board to prevent moisture absorption and generation of resin dust and the like from the end face. It is to provide a printed wiring board that is prevented.

[0006]

According to the present invention, there is provided a printed wiring board characterized in that a conductor is provided on the entire circumference of an end face of the outer shape or a part of the end face. Preferably, conductors are also formed on the front surface and the back surface of the printed wiring board adjacent to the end surface portion provided with the conductor, in an arbitrary width, continuously with the conductor provided on the end surface.

[0007]

By forming the conductor around the end face, it is possible to protect the internal conductor pattern when the printed wiring board is manufactured.

Further, by forming a conductor around the end face, there are the following effects when the printed wiring board is used.
(A) Prevent dust from being generated from the end surface. (B) Prevent moisture absorption from the end face. (C) It is possible to supply power from the end face to the inner layer pattern. (D) Enables grounding from the end surface,
The shield effect can be improved. (E) The sealing effect is obtained by joining the conductor on the end face or around the end face and the housing. (F) Strength increases with the conductor formed on the end face,
It also becomes stronger against warping and twisting to some extent.

Furthermore, the heat dissipation effect of the printed wiring board can be improved by connecting the inner layer conductor and the end surface conductor and bringing the end surface conductor into contact with the housing.

[0010]

1 is a perspective view of a printed wiring board according to an embodiment of the present invention. A conductor pattern 12 is formed on the surface of the printed wiring board 10, and through holes 14 are provided so as to penetrate the printed wiring board 10 as in the conventional printed wiring board. Furthermore, printed wiring board 1
A conductor 16 is also formed on a part of the outer end surface 15 of 0. The conductor 16 is formed only on the end surface 15, or the conductor 18 having an arbitrary width on the front surface and the back surface of the printed wiring board 10 adjacent to the end surface portion where the conductor 16 is provided continuously to the conductor 16 provided on the end surface 15. Are formed.

A hole 20 into which a component is inserted is further formed in the printed wiring board 10, and a conductor 22 is formed on the end surface of the hole 20 and the front and back surfaces of the printed wiring board 10 surrounding the hole 20 with an arbitrary width. It is provided.

In the illustrated embodiment, the printed wiring board 10 is shown.
Although the conductor 16 is formed only on a part of the outer shape end surface 15, the conductor 16 may be formed on the entire circumference of the outer shape end surface 15. Further, in addition to the conductor formed on the entire circumference of the outer end surface, the conductor 18 may be formed with an arbitrary width on the front surface and the back surface of the printed wiring board 10 adjacent to the end surface.

A manufacturing process in the case of partially forming a conductor on the outer end face will be described with reference to FIG. First, an inner layer circuit is formed by a usual method, blackened, and then laminated. Next, the end face is cut into a standard size to form a standard size substrate 30, and the standard size substrate 30 is perforated as shown in FIG. 2A to form a through hole 32. Next, as shown in FIG. 2B, slits 33 are formed in the standard length substrate 30 by router processing to form a plurality of individual substrates 34 connected at the corners.

Then, after desmearing, the entire fixed-length substrate 30 is panel-plated. After that, as shown in FIG. 2C, a desired circuit is formed on the front surface and the end surface by applying an etching resist 36 on the front surface and the end surface, and a predetermined circuit is formed on the front surface and the back surface adjacent to the end surface and the end surface. Form conductors in width.

Instead of applying the etching resist on the surface and the end face, the circuit formation and the conductor on the end face may be formed by a so-called filling method of filling the through hole 32 and the slit 33.

After the anticorrosion treatment or electroless gold plating is applied to the conductor portion, a solder resist is applied. Finally, the individual printed wiring boards 34 shown in FIG. 2D can be manufactured by separating the connecting portions.

When a conductor is formed on the entire circumference of the outer end surface of the printed wiring board, it is completely separated into individual boards at the time of outer shape processing by a router, and then desmear processing and panel plating are performed. Next, after forming a circuit similar to that shown in FIG. 2C, rust prevention treatment is performed and a solder resist is formed to complete a printed wiring board.

Next, various embodiments of the present invention will be described with reference to FIGS. FIG. 3A shows an embodiment in which conductors 40 are formed on the entire circumference and all end faces of the printed wiring board.
A conductor pattern 42 is formed on the surface of the printed wiring board in the same manner as an ordinary printed wiring board, and a plurality of through holes 44 are provided so as to penetrate the printed wiring board. In this embodiment, the printed wiring board can be fixed to the housing all around by using solder or the like, and the sealing effect of the electronic components mounted on the surface can be improved.

FIG. 3B shows an example in which the conductor 40 is formed on a part of the outer circumference of the printed wiring board and the outer end face corresponding to the outer circumference. FIG. 3C also shows an example in which the conductor 40 is formed on a part of the outer periphery of the printed wiring board and the outer end face corresponding to the outer periphery. Further, FIG. 3D shows an example in which the conductor 40 is formed on the entire circumference of the printed wiring board and a part of the outer end surface, and no conductor is formed on the end surfaces of the four corners of the printed wiring board.

FIG. 4A shows an embodiment in which a hole 46 for inserting a component is provided in a printed wiring board, and a conductor 48 is formed on a part of the periphery of the hole 46 and an end surface of the hole 46 corresponding to the hole.
FIG. 4B shows a hole 50 into which a component is inserted in the printed wiring board.
Is provided, and the conductor 48 is formed on the entire circumference and the entire end surface of the hole.

Further, FIG. 4 (C) is shown in FIG. 3 (A) and FIG.
This is an example in which (B) is combined, and the conductors 40 are formed on the entire outer circumference and the entire end surface of the printed wiring board, and the conductors 48 are also formed on the entire circumference and the entire end surface of the hole 50.

Referring to FIG. 5, cross-sectional views of various embodiments are shown. FIG. 5A shows an embodiment in which the conductor 40 is formed on the outer end surface of the printed wiring board. FIG. 5B shows an embodiment in which the conductor 40 formed on the outer end surface and the conductor 52 formed on the inner layer are connected to each other. With this configuration, the heat dissipation characteristics through the inner layer conductor 52 and the conductor 50 on the outer end surface are improved. You can

FIG. 5C shows an embodiment in which the conductor 40 is formed with a predetermined width on the outer surface of the printed wiring board and the front and back surfaces of the printed wiring board adjacent to the outer surface. FIG. 5D shows an embodiment in which the conductor 40 formed on the outer end face and the peripheral portion of the outer face are connected to the inner layer conductor 52, and the heat dissipation characteristics can be improved similarly to FIG. 5B.

FIG. 5 (E) shows an embodiment in which the conductor pattern 42 formed on the surface of the printed wiring board and the conductor 40 formed on the outer end face and the peripheral portion of the end face are connected, and the conductor as a whole has two conductor portions 54a. And 54b, the power can be supplied through the conductor portions 54a and 54b.

[0025]

The printed wiring board of the present invention has the following effects because the conductors are formed on the front and back surfaces of the printed wiring board adjacent to the end face of the outer shape and the end face.

(A) The conductor pattern formed on the surface can be protected. (B) It is possible to prevent generation of dust such as epoxy resin from the end surface. (C) It is possible to prevent moisture absorption from the end surface.

(D) Power can be fed from the conductor on the end face to the inner layer conductor or the conductor pattern on the surface layer. (E) The conductor on the end face can be grounded, and the shield characteristic is improved.

(F) The sealing effect is obtained by joining the conductor on the end face and the housing. (G) The conductor provided on the end face can increase the strength to some extent, and becomes stronger against warping, twisting and the like.

Further, the heat dissipation characteristics can be improved by connecting the inner layer conductor to the conductor provided on the end face and bringing the conductor on the end face into contact with the housing.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment.

FIG. 2 is a diagram showing a manufacturing process.

FIG. 3 is a plan view of various examples.

FIG. 4 is a plan view of various examples.

FIG. 5 is a cross-sectional view of various examples.

[Explanation of symbols]

10 printed wiring board 12,42 conductor pattern 14,32,44 through holes 16 End conductor 18 End face peripheral conductor 20,46,50 holes 22,48 hole end face conductor 52 Inner layer conductor

Claims (4)

[Claims] 1. A printed wiring board, characterized in that a conductor (16) is provided on the entire circumference of the outer end surface (15) or on a part of the end surface. 2. The conductor (16) provided on the end face (15) has an arbitrary width continuously on the front surface and the back surface of the printed wiring board adjacent to the end face portion provided with the conductor (16). 18. The printed wiring board according to claim 1, wherein the printed wiring board is formed. 3. The printed wiring board according to claim 1, wherein the conductors (42, 52) of the inner layer or the surface layer are connected to the conductors (16, 18). 4. Providing holes (20, 46, 50) into which parts are inserted,
The printed wiring board according to any one of claims 1 to 3, wherein conductors (22, 48) are formed with an arbitrary width on an end surface of the hole and a front surface and a back surface of the printed wiring board surrounding the hole.