JPS60109294A - Method of producing flexible circuit 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 [Field of Industrial Application] The present invention relates to a flexible substrate having a conductive pattern formed on a flexible film.
The present invention relates to a method for manufacturing a xipple circuit board.

[Background technology and its problems]

Copper foil or the like is pasted onto the board, and when such flexible boards are subjected to eso-tink processing to form conductive patterns (wiring patterns), the boards shrink or warp due to heat and moisture.

In addition, the kite holes for positioning become deformed, making it difficult to achieve accuracy, and it is difficult to temporarily fix electronic components with solder paste on a warped and deformed board.
Generally, it is difficult to mount electronic components on flexible substrates using automatic mounters. Furthermore, even if the three electronic HI products are mounted using an automatic mounting machine, the flexible board will further form a hot rod shape in the heat flow furnace, making it impossible to perform accurate soldering.

Therefore, conventionally, the work of mounting electronic components on a flexible board has been carried out using a soldering iron, which has had the problem of extremely poor productivity. Further, even when soldering is performed using a soldering iron, there is a drawback that the flexible substrate is deformed by heat.

Therefore, the present invention has been proposed in view of the above circumstances, and when electronic components are mounted on a flexible substrate in which a conductive pattern is formed on a flexible film, the flexible substrate is It does not shrink due to heat or moisture, and it is possible to form a pattern according to the desired Bakun design, and it is possible to mount electronic components on a flexible board using an automatic mounting machine. is not thermally deformed,
Also, various flexible film resins can be used,
It is an object of the present invention to provide a method for manufacturing a flexible circuit board that can also reduce costs by using an inexpensive film.

[Summary of the invention]

In order to achieve the first objective, the method for manufacturing a flexible circuit board of the present invention involves applying a treatment to reduce the adhesive strength on a part or the entire surface of the back surface of the flexible board or the surface of the F board, and using an adhesive. After pasting together the flexible substrate and the gluing board and temporarily gluing them together, we perform a pattern etching process to form a conductive pattern, solder the electronic parts, and then remove the temporarily glued gluing board. It is characterized by peeling off from the substrate.

〔Example〕

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

FIG. 1 sequentially shows the steps of manufacturing a flexible circuit board by the manufacturing method according to the present invention. In the present invention, a flexible substrate is temporarily fixed to a rinsing board, an etching process is performed to form a conductive pattern on the flexible substrate, and electronic components are mounted on the flexible substrate on which a conductive pattern is formed. It is possible to manufacture a flexible circuit board without deforming the flexible board due to water or moisture.

Next, the steps shown in FIG. 1 will be explained in order. Talented, first
As shown in the figure, an oil-repellent coating film 2 is formed on the entire surface of the rigid plate 1 using coach ink, and adhesive strength reduction treatment is performed. By forming this coating film 2 and performing surface treatment,
The adhesive strength of the flexible substrate that is later attached to the rigid board 1, especially the peeling strength (beer strength), can be reduced.

By the way, the above-mentioned rigid plate 1 is made of a plate material having a thickness of 9 mm and a rigidity of 2 uLLrr manufactured by a manufacturer.

As the rigid plate 1, a plastic plate such as Bakelite, paper epoxy, or J-lase epoxy, or a metal plate such as aluminum, stainless steel, tinplate, or iron can be used. Further, the coating film 2 may include silicone resin,
Alternatively, it is formed by applying a coach ink of epoxy resin containing 5% to 30% oil.

At the same time, as shown in FIG.
Apply 1st pattern and paste it on 2nd side $1tl. Here, the flexible substrate 4 has a conductive layer 6 made of copper 2r1 or the like pasted on the surface of a flexible film 5 made of polynisdel or the like. The thickness of the flexible substrate 4 thus formed ranges from 0°I 111JII to 0.
It is about 3 ntm. By the way, flexible fill, -1
5 may be formed using polyether sulfone, polyether imi 1-', aramiso 1-, etc. in addition to polynisdel. The adhesive 3 may be, for example, a thermosetting adhesive such as an epoxy/acrylic rubber adhesive containing 3 to 10 parts of acrylic rubber, or an epoxy/imixol adhesive. can.

Next, the adhesive 3 is thermally cured by leaving the bonded flexible substrate 4 and rigid plate 1 at 120° C. for 4 hours, for example. As a result, the coating film 2
As a result, the flexible substrate 4 and the rigid board 1 are temporarily bonded, and the shear adhesive strength (slip adhesive strength) is 1% or more, and the beer adhesive strength is 10%! / / cm to 500.9
It comes to show interfacial adhesion of / side / degree.

Next, as shown in FIG. 1C, the rigid plate 1 is placed on a carrier (
A conductive pattern 6A is formed on the flexible substrate 4 by pattern etching processing of the flexible substrate 4 temporarily bonded to the lysine board 1 as a lysine. During this etching process, the flexible substrate 4 will not be deformed by heat or moisture. This is because the flexible M[4 is temporarily bonded to the rigid plate 1, which is a gear rear, and shrinkage of the film 5 is suppressed by shear adhesive force. By suppressing deformation in this manner, the conductive bag 6A can be formed in accordance with the desired pattern.

After forming the conductive back cover 6A, it is coated with Tsurutaresis I, and then, as shown in the first diagram, a hole for inserting a component is processed to form a through hole 7. Conventionally, flexible substrates were generally not processed, but according to the present invention, since the flexible substrate 4 is temporarily bonded to the rigid substrate 1, it is easy for the flexible substrate to be processed. Therefore, mounting of components into the through hole 7, which will be performed later, can be done easily.

Next, as shown in FIG. 1E, an automatic mounting machine mounts electronic components 9 such as chip components and IC components onto the flexible substrate 4 using solder paste 8. In mounting this electronic component 9, since the flexible board 4 is temporarily bonded and fixed to the rigid board 1, the flexible board 4 does not curve 1111, and the automatic mounting machine
It is possible to accurately arrange the electronic part heavy ring at a predetermined position on the flexible board 4. Here, the solder base 8 is
For example, a tin-lead alloy powder is mixed with a 70% tin-lead alloy powder by weight.

Next, by placing it in a furnace, the electronic component 9 is soldered to the flexible substrate 4 by, for example, reflow, as shown in FIG. 1F. The flow condition at this time is 220
It is like applying hot air treatment at a temperature of about 260°C for about 40 seconds. In this reflow soldering process,
Since the flexible substrate 4 is temporarily bonded and pressed by the rigid plate 1, dimensional deformation of the flexible substrate 4 due to heat does not occur.

Next, as shown in FIG. 1G, an electronic component 10 that cannot be mounted by an automatic mounting machine is mounted in the through hole 7, and then hand soldering is performed to attach the electronic component 10 to the flexible board 4. Mounting and soldering of this electronic component 10
In the first step, the flexible board 4 is temporarily connected to the sono board 1, so that work can be carried out efficiently. In addition, deformation of the flexible substrate 4 due to heat during manual soldering does not occur. Incidentally, instead of performing manual soldering, the electronic component 10 may be mounted in the through hole 7 in advance, and the reflow semi-IB process may be carried out in a step not shown in FIG. 1.

In this way, the electronic components 9° and 10° are mounted on the flexible board 4.
was mounted, as shown in Fig. 1 II, the flexible substrate 4 was separated by peeling off the flexible substrate 4/board 1 by using the coating 11ψ2 mentioned above for adhesive strength reduction treatment, and
Flexible circuit board 1 with electronic components 9 and 10 mounted on it
1 to 7 (I rukokichi is possible.In addition, instead of scraping, use a solvent to melt the adhesive 3,]l/・1-
The mounting board 4 and the rigid board 1 may be separated.

According to the present invention, since the flexible substrate 4 is temporarily bonded to the flexible substrate 1, the inconvenience of handling, which is a drawback of the flexible substrate, is eliminated, and it can be handled in the same way as a rigid substrate. This not only improves the workability of etching processing and Norfresist coating, but also
Components can be mounted reliably using an automatic mounting machine, and productivity is also extremely high.

In addition, a flexible film 5 constituting the flexible substrate 4
Various flexible film resins can be used, and the cost of the flexible circuit board can be lowered by using particularly inexpensive polynysdel.

Note that instead of using a thermosetting adhesive as the adhesive 3, an ultraviolet curable epoxy/acrylate adhesive or the like may be used. In this case, the adhesive can be cured, for example, by irradiating it with ultraviolet rays after enotink processing.

At the same time, another embodiment of the present invention will be explained based on FIG. In this example, a conductive layer 6 is pasted on the surface of a visibility film 5 (= J digits), and coating 1 and 2 for the adhesive strength reduction treatment described above are formed on the entire back surface of the flexible substrate 4 using coach ink. Two layers of three adhesives are formed on 2-F. Then, these are pasted on the rigid board 1, and the flexible board 4 is temporarily attached to the resin board 1. That's what I do.

Moreover, FIG. 3 shows still another embodiment.

In this example, adhesive 13 is applied to the back surface of flexible substrate 4 having conductive layer 6 on the surface of flexible film 5.
It can be pasted using a heated roll heated to around 0°C. The adhesive 13 is an epoxy/phenol adhesive, an epoxy/nitrile adhesive, or the like, which has a strong shear adhesive strength and a weak beer adhesive strength. By pasting these onto the rigid board 1, the flexible substrate 4 can be temporarily bonded to the rigid board 1.

Incidentally, in the above embodiment, the coating film 2 for adhesive strength reduction treatment is formed on the entire surface of the rigid board 1 or the back surface of the flexible substrate 4, but the adhesive strength reduction treatment is applied not on the entire surface but on a part of the surface. Alternatively, a rigid/flexible composite circuit board may be formed by forming a coating film and partially detaching the rigid plate from only the portion that has been subjected to adhesive strength reduction treatment.

In this case, soldering of electronic components to the flexible board part from which the rigid plate has been partially detached is done by using a solder dip, for example, by immersing the board in molten solder at 250°C for 5 seconds in a solder wave. It can be processed using a device.

Although the flexible substrate 4 described above is a single-sided, single-layer flexible substrate, the present invention can also be applied to a single-sided, multilayer build-up flexible substrate.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, adhesive strength reduction treatment is performed, a flexible board is temporarily bonded to a rigid board, edge processing etc. and component mounting are performed, and after a series of processing is completed, the flexible board is attached to the rigid board. Flexible circuit boards are manufactured by peeling and separating rigid boards. By doing this, the flexible substrate is pressed against the rigid plate by shear adhesive force, and the flexible substrate is prevented from being deformed by heat or moisture during etching.

Therefore, it is possible to form a conductive pattern according to a desired pattern pattern. In addition, by temporarily adhering electronic components to a rigid board, electronic components can be reliably mounted on a flexible board using an automatic mounting machine, and productivity can be improved. Furthermore, the flexible board will not be deformed by the heat generated during reflow soldering or manual soldering. Furthermore, various kinds of flexible film resins can be used for the flexible circuit board, and in particular, by using an inexpensive OJ flexible film such as polyester, the cost of the manufactured flexible circuit board can be lowered.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view sequentially showing the steps of manufacturing a flexible circuit board by the manufacturing method according to the present invention, and FIGS. 2 and 3 are cross-sectional views showing other embodiments of the present invention. 1・・・・・・・・・・・・・・・ Rigid plate 2・・
・・・・・・・・・・・・ Coating film 3.13...
・・Adhesive 4 ・・・・・・・・・・・・・ Flexible substrate 5 ・・Flexible film 6
・・・・・・・・・・・・・・・Conductive layer 6A・・・・・・
......Conductive pattern 7...
...Through hole 8...Solder base 9.10...Electronic component 11...Flexible circuit Substrate patent applicant Sony Corporation representative Patent attorney Kodo Koike 1) Published by Ei - Figure 2 Figure 3

Claims (1)

[Claims] The back of the flexible board or part or all of the surface of the lysine F board is treated to reduce adhesive strength, and the flexible board and the JID board are temporarily bonded together using an adhesive, and then a conductive pattern is formed. A manufacturing method of a flexible circuit board; Saka's manufacturing method is characterized in that after performing a soldering process and soldering an electronic part, the rigid plate of the temporarily bonded part is peeled from the flexible board.