JPS60161693A - Printed board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to automatic recognition technology, and in particular to technology that is effective when applied to automatic mounting of electronic components on printed circuit boards.

[Background Art] As semiconductor devices become more highly integrated, the number of leads that are their external terminals tends to increase, and at the same time, there are demands for electronic devices to be more diverse, more sophisticated, and even smaller.

Therefore, it is necessary to mount a wide variety of electronic components on the same printed circuit board at high density, but it is extremely difficult to perform this mounting work accurately and reliably.

In particular, for printed circuit boards used to mount flat packaged semiconductor devices, the solder pads for mounting also have a position recognition function, and the position is confirmed using an optical recognition device etc. during the process. It is possible to perform automatic implementation.

However, the inventors of the present invention have discovered that as the number of leads in a semiconductor device increases, it becomes difficult to recognize positions and the like based on solder bands.

That is, as the number of leads increases and the lead 11 becomes narrower, soldering the leads becomes more difficult. Therefore, in order to ensure soldering, it is necessary to form thick solder pads to improve soldering properties.

However, when fusing is performed after printing a thick solder paste in order to form a thick solder band, the solder band surface becomes noticeably curved due to the effect of the surface tension of the solder during melting, so the solder pad It becomes very difficult to employ the above-mentioned recognition method of identifying the light reflected on the surface of the object using a light-receiving element or the like.

In addition, depending on the recognition method using solder pads for mounting, it is difficult to provide multiple recognition functions. Therefore, when mounting multiple types of electronic components, a human confirmation process is required and the mounting process is completely completed. The inventors also discovered the problem that automation is difficult.

[Object of the Invention] An object of the present invention is to provide a technology that enables automatic recognition when electronic components are mounted on a printed circuit board.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the Invention] A brief overview of typical inventions disclosed in this application is as follows.

That is, by providing a recognition mark at an arbitrary position on a printed circuit board for electronic component mounting, automation of electronic component mounting is achieved.

[Embodiment] FIG. 1 shows a printed circuit board 1 which is an embodiment of the present invention.
FIG. 2 is a perspective view schematically showing a part of the cage-type semiconductor device 2 and a furanodopa before being mounted on the substrate. That is, the external leads 5 protruding from the four sides of the thin resin sealing body are bent and mounted on the printed circuit board 1 in a so-called surface mounting state.

What is shown in FIG. 1 is one unit mounting section for mounting a flat package type semiconductor device 2, which is an electronic component, on a printed circuit board, and the mounting section has a nickel-plated copper layer on its surface. The solder pads 4 are formed on the nickel surface at the end of the wiring 3, and the same number of solder pads 4 as the external leads 5 of the semiconductor device 2 are arranged in parallel at corresponding positions.

Note that the semiconductor device 2 is lowered onto the printed circuit board 1 in the direction of the dashed-dotted arrow, and heat-treated while applying pressure with the external leads placed on the solder pads 4. The implementation is complete.

Further, in this embodiment, only a part of the external leads and solder pads are shown, and the others are omitted with dashed lines.

FIG. 2 shows a printed circuit board 1 which is an embodiment of the present invention.
This is a plan view showing the outline of .

The printed circuit board of this embodiment is provided with a metal pad 6 as a recognition mark near the mounting solder pad 4 of the printed circuit board 1 shown in FIG.

The metal pad 6 is formed of a thin film of solder. The shape is arbitrary, and as shown in this embodiment, numbers or other characters may be etched on the metal pad 6 to remove the metal part, or the shape of the pad itself may be changed. can.

In this way, the metal pad 6 for recognition is placed near the mounting part.
By providing a pad shape, accurate positioning is possible even for semiconductor devices that have a large number of lead bins, which makes it possible to automate high-density mounting.Additionally, by adding a recognition function to the shape of the pads, It will now be possible to automatically mount two or more types of electronic components on a device.

The method for manufacturing the printed circuit board of this example is to pattern a gold-copper layer adhered to the surface of an insulating substrate such as glass-epoxy using a conventional method, and then coat the surface of the copper layer with a method such as nickel plating. Then, a very thin layer of solder is applied by plating on the mounting solder pad 4 formation portion and the recognition metal pad 6 formation portion.

Thereafter, a solder paste is applied by printing only to the portion where the mounting solder pad 4 is to be formed using a conventional method. By subsequently performing a fusing process, a solder band is formed with a thickness sufficient to solder even a semiconductor device having a large number of leads. Further, even if fusing is performed, since the solder pad, which is the metal pad 6, is very thin, its surface can be maintained in a flat state, so that sufficient recognition ability can be ensured even with an optical method.

As described above, according to the present invention, not only the mounting strength of electronic components can be improved, but also the mounting accuracy can be improved, and furthermore, it is possible to achieve automation of continuous mounting of a wide variety of electronic components.

[Effect (1): By providing a recognition mark at any position on the printed circuit board 1 for electronic component mounting, automatic recognition of the mounting position becomes easy, so automatic mounting can be performed accurately. Can be done.

(2) By providing a recognition mark near the mounting section, the accuracy of position recognition can be improved, so the accuracy of automatic mounting of semiconductor devices having a large number of lead bins can be improved.

(3) By changing the shape of the recognition mark, the product type can be identified at the same time, so it is possible to automate the continuous mounting of various types of electronic components on the same printed circuit board.

(4) By forming the metal pad for recognition with a thin film of solder, in the case of a printed circuit board for a flat package type semiconductor device, the metal band can be formed in the same manufacturing process.

(5) By forming the metal pad for recognition with a thin film of solder, the surface flatness can be maintained even after fusing treatment, so that accurate recognition can be performed using an optical recognition device.

(6) According to (11 to (3) and (5)), it is possible to automatically mount electronic components having a large number of lead terminals in a continuous and high-density manner even if they are of various types.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, an example has been described in which solder is used as the material for the metal pad for recognition, but it goes without saying that it may be made of other metals such as aluminum.

Further, although the printed circuit board shown in the embodiment uses a method of further plating a thin layer of solder on nickel, the underlying nickel itself may be used as the metal pad.

[Field of Application] In the above explanation, the invention made by the present inventor was mainly applied to a printed circuit board for a flat package type semiconductor device, which is the field of application that formed the background of the invention, but the present invention is not limited thereto. For example, the present invention can be applied to printed circuit boards for semiconductor devices made of DIP packages or for mounting various other electronic components.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a part of a printed circuit board according to an embodiment of the present invention and a semiconductor device mounted on the circuit board, and FIG. 2 is a schematic plan view of the printed circuit board according to the present invention. 1... Printed circuit board, 2... Semiconductor device, 3...
・Wiring, 4...Solder pad, 5...External lead, 6
...metal pad.

Claims (1)

[Scope of Claims] 1. A printed circuit board having an electronic component mounting section, characterized in that a recognition mark is provided at an arbitrary position on the circuit board. 2. The printed circuit board according to claim 1, wherein the electronic component mounting portion is formed of a solder pad. 3. The printed circuit board according to claim 1 or 2, wherein the mark is formed of a metal band. 4. The printed circuit board according to claim 3, wherein the metal pad is formed of a thin film of solder. 5. The printed circuit board according to claim 1, wherein the mark is provided near the electronic component mounting section.