JPH062730U - Printed wiring board - Google Patents

Abstract

(57) [Abstract] [Purpose] Even when the board thickness is thin, it is possible to prevent warpage during component mounting and to mount components accurately. [Structure] A copper foil 5 covers substantially the entire surfaces of both sides of a waste substrate 3 which is continuously provided on the outer periphery of a product substrate 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a printed wiring board, and more particularly to a printed wiring board suitable for preventing warpage of a thin substrate.

[0002]

[Prior art]

 In conventional thin printed wiring boards, in order to prevent the displacement of the mounted components due to the stress applied when mounting the chip components, the inner layer of the waste substrate that is continuously provided around the product substrate. Was completely covered with copper foil to compensate for the lack of strength of the board.

A configuration of an example of such a printed wiring board is shown in FIG. This example shows the case of a four-layer printed wiring board, in which the predetermined portions of the two substrates 1a and 1b are product substrates 2a and 2b, and the peripheries thereof are waste substrates 3a and 3b. Wiring patterns 4a and 4b are formed on both surfaces of the product substrates 2a and 2b, and almost the entire inner layers of the discarded substrates 3a and 3b facing each other are covered with copper foils 5a and 5b.

However, electronic devices have recently become smaller, thinner, and lighter, and therefore printed wiring boards have also been made thinner, and there has been a demand for boards having a thickness of 1 mm or less. As a result, there has been a problem that the strength of the printed wiring board against stress during component mounting is insufficient if only the inner layer of the scrap substrate is covered with the copper foil. Then, there is a possibility that warpage may occur on the substrate and component mounting may not be performed accurately.

[0005]

[Problems to be solved by the device]

 As described above, in the conventional printed wiring board, since only the inner layer of the waste board is covered with the copper foil, there is a problem that the strength is insufficient when the board thickness is thin. As a result, if stress is applied during component mounting, the board may warp and component mounting may not be performed accurately.

The present invention has been made in view of such a point, and even when the board thickness is thin, it is possible to prevent warpage during component mounting and to perform accurate component mounting. An object is to provide a printed wiring board.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a printed wiring board including a product substrate on which a wiring pattern is printed and a waste substrate continuously provided on the outer periphery of the product substrate. The feature is that a metal foil layer is formed on almost the entire surface of both sides.

[0008]

[Action]

 According to the above configuration, since the metal foil layers are formed on almost the entire surfaces of both sides of the scrap board, it is possible to prevent warpage due to stress applied during component mounting and to accurately mount the chip parts on the printed wiring board. Can be implemented.

[0009]

【Example】

 An embodiment of the printed wiring board of the present invention will be described below with reference to the drawings.

1 and 2 show the configuration of an embodiment of the present invention. In these figures, parts corresponding to those of the conventional example shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted as appropriate. The feature of this embodiment is that almost the entire surfaces of both sides of the scrap substrates 3a and 3b are covered with copper foils 5a, 5b, 5c and 5d. In this embodiment, as shown in FIG. 2, four product substrates 2 are provided on the substrates 1a and 1b.

According to this embodiment, since both sides of the scrap substrates 3a and 3b are covered with the copper foil 5, the strength of the printed wiring board is increased. As a result, it is possible to prevent the warp of the substrate 1 due to the stress when the chip component 4 is mounted, and to mount the component accurately.

Although a four-layer printed wiring board has been described in the above embodiment, it can be applied to a printed wiring board having six layers or more, and the same effect can be obtained. Also, the number of product substrates 2 provided on the substrate 1 is not limited to four. Further, the metal foil covering both surfaces of the waste substrate 3 is not limited to the copper foil, and may be another metal foil.

[0013]

[Effect of device]

 As described above, according to the printed wiring board of the present invention, since the metal foil layers are formed on substantially the entire surfaces of both sides of the waste board, the strength of the printed wiring board is increased, and the printed wiring board is subjected to the response when mounting the chip component The warp can be prevented from occurring, and accurate component mounting can be performed.

[Brief description of drawings]

FIG. 1 is a sectional view taken along line XX of FIG. 2 showing the configuration of an embodiment of a printed wiring board of the present invention.

FIG. 2 is an external perspective view showing the configuration of an embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing the configuration of an example of a conventional printed wiring board.

[Explanation of symbols]

2 Product board 3 Discarded board 4 Wiring pattern 5 Copper foil (metal foil layer)

Claims (1)

[Scope of utility model registration request] 1. A product substrate on which a wiring pattern is printed,
A printed wiring board comprising a waste substrate continuously provided on the outer periphery of the product substrate, wherein a metal foil layer is formed on substantially the entire surfaces of both sides of the waste substrate.