JPH05218598A - Printed-wiring board - Google Patents

Abstract

PURPOSE:To provide a printed-wiring board free from a possibility of damage or shrinkage by heat, excellent in durability, and reliable. CONSTITUTION:A current conducting pattern 2a, and a reinforcing pattern 2b formed to connect chip parts at parts excluding the peripheries of the current conducting pattern 2a are provided on an insulating board 1. The increase of the size change ratio or warp, etc., of a printed-wiring board by heat can be prevented, since the rigidity of the printed-wiring board can be raised by forming the patterns so as to leave cupper foil as windely as possible at parts of the insulating board other than the current conducting pattern 2a also.

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, and more particularly to a flexible printed wiring board.

[0002]

2. Description of the Related Art A conventional printed wiring board is made of glass epoxy, as shown in FIG.
By etching the copper foil formed on the insulating substrate 10 such as polyimide glass epoxy, bakelite, polyimide film, polyester film, PPO, etc., and removing all the copper foil other than the conductor pattern 20 or the plating leads and the alignment marks. It was manufactured.

However, in recent years, flexible printed wiring boards having a substrate thickness of 0.5 mm or less have been used. However, when a printed wiring board is manufactured by such a conventional method, the printed wiring board may drop from a conveyance facility in an etching process, Winding around
There was a possibility that the printed wiring board would be damaged due to splashing. Further, in the process of directly applying heat, there are problems that the shrinkage of the insulating substrate is increased, warpage occurs, and deterioration is accelerated.

Particularly, as a means for preventing warpage, another step such as the use of a warpage prevention jig or a method of attaching a warpage prevention bar to a printed wiring board has been required. Furthermore, removing all of the copper foil other than the pattern requires a long processing time for etching and is high in running cost.

[0005]

An object of the present invention is to solve the above conventional problems, and to provide a reliable and reliable printed wiring board which is free from damage and shrinkage due to heat. To aim.

[0006]

A printed wiring board of the present invention that achieves the above object is a printed wiring board having an insulating substrate and a conductor pattern made of a conductive material formed on the insulating substrate. The pattern is composed of an electric conduction pattern and a reinforcing pattern formed on a portion of the substrate other than the periphery of the electric conduction pattern.

[0007]

According to the present invention, the rigidity of the printed wiring board can be increased by forming a pattern so that the maximum amount of copper foil can be spread on the portion of the insulating substrate other than the pattern for electrical conduction. Along with this, it is possible to prevent the dimensional change rate of the printed wiring board due to heat, warpage, and the like.

Besides, by reducing the etching portion, low pollution, resource saving and low running cost can be achieved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the printed wiring board of the present invention will be further described below with reference to the drawings. In the printed wiring board shown in FIG. 1, a conductor pattern 2 made of a conductive material such as copper foil is formed on an insulating substrate 1 made of glass epoxy, polyimide glass epoxy, bakelite, polyimide film, polyester film, PPO, or the like. The conductor pattern 2 is composed of an electric conduction pattern 2a and a reinforcing pattern 2b formed on a portion of the substrate other than the periphery of the electric conduction pattern 2a.

Although not shown, alignment marks, plated leads, etc. are formed as the electrical conduction pattern 2a as required. The reinforcing pattern 2b reinforces the thickness of the insulating substrate 1 and prevents the printed wiring board from being dimensionally changed or warped by heat. A chip component or the like mounted on a printed wiring board is mounted on the electrical conduction pattern 2a.
By making the electrical conduction pattern 2a thick, it is possible to prevent the printed wiring board from being dimensionally changed or warped due to heat.

As a method of manufacturing such a printed wiring board of the present invention, there is a subtractive method, for example. To manufacture by the subtractive method, as shown in FIGS. 3A to 3D, first, in a resist process which is the first process shown in FIG. Board 1
On the surface of No. 00, only a necessary portion as the conductor pattern 400 is covered with the etching resist 300.

Subsequently, in the etching step which is the second step shown in FIG. 3 (c), an etching solution that dissolves the copper foil 200 is sprayed onto the surface of the copper foil, applied, etc., to form a copper foil other than the conductor pattern portion. Are dissolved and removed. As a result, the copper foil covered with the etching resist 300 remains without being dissolved. Finally, in a resist stripping step which is a third step shown in FIG. 3D, the etching resist 300 is stripped and removed to expose the conductor pattern 400.

In addition to this, as an additional manufacturing method, there is an additive method in which a conductive material is deposited and fixed only on the conductor pattern portion based on the circuit design on the insulating substrate to which the copper foil is not adhered to form the conductor pattern portion. is there. According to such a method for manufacturing a printed wiring board of the present invention, since only the peripheral portion of the electrical conduction pattern 2a needs to be removed, the time required for etching can be shortened and the amount of etching waste liquid can be reduced. Therefore, low pollution, resource saving, and low running cost can be achieved.

In the present embodiment, the single-sided printed wiring board in which the conductor pattern is formed only on one surface of the insulating substrate has been described, but the present invention is a double-sided printed wiring board in which the conductor pattern is formed on both front and back surfaces of the insulating substrate. Needless to say, the present invention can be applied to a multilayer printed wiring board having copper body patterns formed not only on the front and back surfaces of the insulating substrate but also on the inner surface.

Other Examples As an example of a double-sided printed wiring board, using a material in which a copper foil having a thickness of 0.035 mm is adhered to both sides of a board having a thickness shown in Table 1, as shown in FIG. A printed wiring board on which a conductive pattern and a reinforcing pattern were formed was prepared, and the rate of increase of the stiffness with respect to the stiffness of the substrate itself was measured. The results are shown in Table 1.

The remaining copper rate other than the pattern portion is preferably 40% or more.

[0017]

[Table 1]

As is clear from Table 1, the thinner the insulating substrate is, the larger the rate of increase in rigidity is, and it is understood that the rate of dimensional change of the wiring board due to heat, warpage, etc. are prevented.

[0019]

According to the present invention, the rigidity of the printed wiring board can be increased by forming a pattern so that the maximum amount of copper foil can be spread on the portion of the insulating substrate other than the pattern for electrical conduction. Along with this, it is possible to prevent the dimensional change rate of the printed wiring board due to heat, warpage, and the like.

Besides, by reducing the etching portion, low pollution, resource saving and low running cost can be achieved.

[Brief description of drawings]

FIG. 1 is a front view and a sectional view of a printed wiring board of the present invention.

FIG. 2 is a manufacturing process diagram of the printed wiring board of the present invention.

FIG. 3 is a front view and a cross-sectional view of a conventional printed wiring board.

[Explanation of symbols]

 1 ... Insulating substrate 2 ... Conductor pattern 2a ... Electrical conduction pattern 2b ... Reinforcing pattern

Claims (1)

[Claims] 1. A printed wiring board comprising an insulating substrate and a conductor pattern made of a conductive material formed on the insulating substrate, wherein the conductor pattern excludes an electric conduction pattern and the periphery of the electric conduction pattern. A printed wiring board, comprising: a reinforcing pattern formed on a portion of an insulating substrate.