JP2562183B2 - Release sheet temporary adhesion flexible circuit manufacturing method and release sheet temporary adhesion flexible circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is obtained by a method of manufacturing a plurality of thin and highly flexible circuits in a state of being temporarily adhered to a release sheet, and a method thereof. Release sheet temporary adhesion flexible circuit.

[Conventional technology]

Generally, a flexible circuit which is thin and has high flexibility is manufactured as follows. That is,
Exposure, pattern formation, etching and the like are performed on the copper foil surface of the copper-clad flexible circuit board to form a plurality of flexible circuits in an array. Next, a coverlay film made of a polyimide resin, which is perforated at a desired position to allow component mounting or wiring and has an adhesive coated on one side, is laminated on the copper foil surface on which the flexible circuit is formed. . Then, after subjecting the circuit surface to a predetermined surface treatment, a flexible sheet made of polyethylene phthalate is further stacked with the four corners fixed. Then, in that state, the flexible circuit is manufactured by inserting a blade along each flexible circuit and cutting the flexible circuit. Each of the flexible circuits thus obtained is adhered to the punched portion of the copper-clad flexible circuit board in a punched state (the outer peripheral portion of the flexible circuit and the punched portion of the copper-clad flexible circuit board). (Adhering to the inner peripheral portion due to adhesive friction), and is supplied to the consumer after inspection as it is.

[Problems to be solved by the invention]

However, when passing through the inspection process and the transportation process in the above-mentioned state, the flexible circuit is detached from the punched portion of the copper-clad flexible circuit board with a slight impact, so that the handleability is extremely poor. In addition, each flexible circuit is in a state of being buried on the copper foil surface of the copper-clad flexible circuit board, so to speak, there is a problem that it is difficult to count together with the brown color of the copper foil surface when counting the number of members. . Moreover, when the flexible circuit is used, the flexible circuit is removed from the punched portion of the copper-clad flexible circuit board, but it is complicated to remove the flexible circuit from the punched portion each time it is used. In addition, the copper-clad flexible circuit board and flexible sheet after the flexible circuit is removed should be discarded as unnecessary parts. Requested.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a method for producing a release sheet temporary adhesive flexible circuit which is excellent in handleability and workability and does not cause a large amount of unnecessary portions during use, and the release sheet temporary adhesive flexible circuit.

[Means for solving problems]

In order to achieve the above object, the present invention provides a step of forming a plurality of flexible circuits on a metal foil surface of a metal foil-clad flexible circuit substrate, and a step of attaching a film material to the metal foil surface after the circuit formation. And a step of adhering the release sheet through the ultraviolet curable weak adhesive sheet layer to the film material, and a blade along each flexible circuit from the surface opposite to the metal foil surface of the metal foil-clad flexible circuit board. A flexible circuit punching step to reach the release sheet to the release sheet, and a removal step of leaving the punched flexible circuit on the release sheet and peeling and removing the other portions of the flexible circuit substrate from the release sheet, The first gist is that the flexible circuit board is provided with an irradiation step of irradiating the sheet surface of the release sheet from which the peeling has been removed with ultraviolet rays. Is a manufacturing method of irradiating the entire back surface of the release sheet with ultraviolet rays between the flexible circuit punching step and the removing step, and the release sheet temporary adhesive flexible circuit obtained by the above manufacturing method is the third aspect. Use as a summary.

[Action]

That is, according to the present invention, a plurality of flexible circuits to be a product are temporarily adhered in an array state on a release sheet. Moreover, since the UV-curable weak adhesive sheet layer formed on the sheet surface of the release sheet loses its adhesive force by irradiation with ultraviolet rays, the sheet surface of the release sheet has no adhesive force. Therefore, at the time of inspection and transportation, a plurality of release sheets can be stacked, and at that time, the flexible circuit is temporarily adhered to the release sheet and does not fall off, which is excellent in handleability. Further, since it is sufficient to carry only the release sheet, the carrying efficiency is improved. Besides,
Since the flexible circuit is detached from the copper-clad flexible circuit board and is itself arranged and temporarily adhered on the release sheet, it is easy to count the number of members. Further, at the time of use, a flexible circuit placed on the release sheet in a state of being raised from the sheet surface of the release sheet is peeled off from the release sheet by using the raised portion as a clue. Since this is sufficient, it is not necessary to perform the complicated work of removing the flexible circuit from the punched portion as in the conventional case. In addition, since the unnecessary portion is only the release sheet, the inconvenience of generating a large amount of unnecessary portions on the consumer side can be avoided at the same time.

 Next, examples will be described.

〔Example〕

1 to 7 show an embodiment of the present invention. That is, FIG. 1 and FIG. 2 show the copper-clad flexible circuit board 9 (the board is made of polyimide) on the copper foil surface 3.
1 shows a circuit board 1 in which a plurality of flexible circuits 2 are formed by exposure, pattern formation and etching by a conventionally known method, and a polyimide coverlay film 5 is attached to a copper foil surface 3 of the flexible circuit 2. Reference numeral 4 is a terminal portion of the flexible circuit 2. According to the present invention, as shown in FIGS. 3 and 4, on the cover lay film 5 surface of the circuit board 1 of FIG.
A release sheet 6 made of transparent polyethylene terephthalate whose entire surface is coated with a UV curable weak adhesive
Then, the surface is aligned with the surface of the cover lay film 5 and pressure is applied thereto to temporarily bond. The above-mentioned UV-curable weak adhesive (commercial name ELEPHOLDER, manufactured by Nitto Denko Corporation) is
The initial adhesive strength of 400-500g / 20mm decreases to 10-20g / 20mm by irradiating 460mJ of ultraviolet ray of 365nm wavelength. But,
Even before irradiation with ultraviolet rays, the adhesive force itself is not so large, so that it can be peeled off after adhesion. Next, the copper-clad flexible circuit board 9 to which the release sheet 6 is temporarily adhered is turned over, and as shown in FIG. 5, a mold having a seal blade 7 having the same shape as the entire shape of the flexible circuit 2 is used. Punch the flexible circuit 2. At this time, the sealing blade 7 is penetrated through the copper-clad flexible circuit board 9 and further penetrated to about half the thickness of the release sheet 6 and stopped there. As a result of this half-cutting, the release sheet 6 maintains its initial shape, and each flexible circuit 2 is temporarily separated from the punched portion of the copper-clad flexible circuit board 9 and is temporarily separated from the release sheet 6 by an independent state. It is glued. Next, as shown in FIG. 6, the copper-clad flexible circuit board 9 is peeled from the release sheet 6 against the temporary adhesive force of the adhesive. In this case, since the copper-clad flexible circuit board 9 is wholly continuous, the whole is easily peeled by peeling from one end side to the other end side. However, since the flexible circuit 2 is temporarily adhered to the release sheet 6 in an independent state by the punching, the flexible circuit 2 remains in the temporary adhesion state on the release sheet 6 regardless of the peeling portion. Then, the sheet surface of the release sheet 6 (the surface where the flexible circuit 2 remains) is irradiated with ultraviolet rays from an ultraviolet ray irradiator (not shown). In this case, the flexible circuit 2 is temporarily adhered to the sheet surface of the release sheet 6 as shown in FIG. 7, but is applied to the surface portion of the release sheet 6 where the flexible circuit 2 does not exist. The UV-curable weak adhesive sheet layer is exposed. But,
Since this adhesive loses its adhesive force due to the irradiation of the ultraviolet rays, there is no fear that dust or the like will adhere, and it can be stacked. However, since ultraviolet rays do not pass through the flexible circuit 2 (in particular, do not pass through the copper-clad flexible circuit board 9), the ultraviolet-curable weak adhesive sheet layer below the flexible circuit 2 does not lose its adhesive force and is therefore flexible. The circuit 2 remains in the initial temporarily fixed state.

In the release sheet temporary adhesive flexible circuit thus obtained, as shown in FIG.
Are temporarily bonded on the release sheet 6 in an array state. Therefore, at the time of use, the end portion of the flexible circuit 2 is lifted and easily peeled off. In order to further facilitate this peeling, the release sheet 6 is bent from the central portion in a longitudinal direction along the longitudinal direction to be folded in two. That is, when the release sheet 6 is bent, the upper and lower ends of the flexible circuit 2 are peeled off and lifted by the elasticity of the flexible circuit 2 itself. Therefore, it is possible to easily peel the whole by using the lifting portion as a clue.

Incidentally, in the above-mentioned embodiment, after the unnecessary portion outside the circuit is removed through the flexible circuit punching step, the ultraviolet irradiation is performed, but the ultraviolet irradiation is moved between the flexible circuit punching step and the unnecessary portion outside the circuit removing step, The entire back surface of the release sheet 6 may be lightly irradiated with ultraviolet rays from the back surface of the mold sheet 6 (the surface on which the flexible circuit 2 is not temporarily adhered). As a result, the adhesive force of the UV-curable weak adhesive sheet layer applied to the entire sheet surface of the release sheet 6 is reduced, so that it is possible to easily remove the unnecessary portion outside the circuit. In this case, the UV-curable weak adhesive sheet layer coated surface is exposed in the removal trace of the unnecessary portion outside the circuit, but since the adhesive strength of the adhesive is lowered by the irradiation of ultraviolet rays, most of the problems such as dust adhesion are not caused. It does not occur and can be stacked. The flexible circuit 2 is temporarily fixed to the release sheet 6 by the adhesive force of the ultraviolet-irradiated weak adhesive sheet layer, which has some adhesive force although the adhesive force is reduced by the ultraviolet ray irradiation. Therefore, at the time of use, the end portion of the flexible circuit 2 is lifted and easily peeled off.

Although the flexible circuit 2 is peeled from the release sheet 6 by using the bending of the release sheet 6 in the above-described embodiment, compressed air may be used. Further, the residual unnecessary copper foil may be removed after the flexible circuit 2 is formed. Further, the ultraviolet irradiation type weak adhesive applied to the surface of the release sheet 6 does not move to the cover lay film 5 of the copper-clad flexible circuit board 9 when the release sheet 6 is bonded to the copper-clad flexible circuit board 9. As described above, one having a larger adhesive force to the release sheet 6 than the adhesive force to the coverlay film 5 is used. However, even if the adhesive force with respect to both is similar, if the surface of the release sheet 6 is roughened, the adhesive force with respect to the release sheet 6 becomes relatively high, and there is no problem.
The adhesive may be applied to the coverlay film 5 without applying it to the release sheet 6.

〔The invention's effect〕

As described above, according to the manufacturing method of the present invention, by the steps of adhering the release sheet, half-cutting, and peeling the unnecessary portion,
It is possible to efficiently manufacture the release sheet temporary adhesion flexible circuit in which the film is temporarily adhered in an aligned state on the release sheet. The obtained release sheet temporary adhesion flexible circuit is excellent in handleability because the circuit itself is temporarily adhered to the release sheet, and the number of flexible circuits can be easily inspected. In addition, since it can be easily peeled off from the release sheet, it can be used for automatic mounting at the time of use, and the unnecessary copper-clad flexible circuit board part has been removed in advance, and a large number of unnecessary parts will be generated on the user side. Never.
In addition, it is not necessary to transport unnecessary parts, which improves transport efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view of a circuit board used in an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA 'of FIG. 3, and FIG. 3 is a perspective view of the circuit board of FIG. Figures 4 and 5 are B-
B'cross section, FIG. 5 is an explanatory view for half-cutting it.
FIG. 6 is an explanatory view of peeling and removing an unnecessary portion from the release sheet and above, and FIG. 7 is a perspective view of the release sheet temporary bonding flexible circuit of the present invention. 1 ... Circuit board, 2 ... Flexible circuit, 5 ... Coverlay film, 6 ... Release sheet, 9 ... Copper clad flexible circuit board

 ─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-62-86788 (JP, A) JP-A-55-67184 (JP, A) JP-A-2-9194 (JP, A) JP-A 62- 117385 (JP, A) JP-B 3-47596 (JP, B2) JP-B 3-47595 (JP, B2)

Claims (3)

(57) [Claims] 1. A step of forming a plurality of flexible circuits on a metal foil surface of a metal foil-clad flexible circuit substrate, and a step of attaching a film material to the metal foil surface after the circuit formation,
The step of adhering the release sheet to the film material via the ultraviolet curable weak adhesive sheet layer, and inserting a blade along the flexible circuit from the surface opposite to the metal foil surface of the metal foil-clad flexible circuit board. A flexible circuit punching process for reaching the release sheet to the release sheet; a removal process for leaving the punched flexible circuit on the release sheet and removing and removing the other portions of the flexible circuit substrate from the release sheet; A method of manufacturing a release sheet temporary adhesion flexible circuit, comprising: an irradiation step of irradiating the sheet surface of the release sheet from which the circuit board has been peeled off. 2. The ultraviolet ray irradiating step is moved between the flexible circuit punching step and the removing step so that the surface of the release sheet opposite to the flexible circuit forming side is irradiated with the ultraviolet ray. (1) A method for producing a release sheet temporary adhesion flexible circuit according to the above description. 3. A release sheet having a UV-curable weak adhesive sheet layer formed on the entire surface of the sheet, and a plurality of flexible circuits having a linear overall shape, the longitudinal direction of which is substantially orthogonal to one edge of the release sheet. The UV curable weak adhesive sheet layers are arranged at a predetermined interval in this state and are temporarily adhered by the adhesive force of the ultraviolet curable weak adhesive sheet layer, and the adhesiveness of the sheet surface portion of the release sheet where the flexible circuit does not exist is substantially disappeared by ultraviolet irradiation. Release sheet temporary adhesion flexible circuit characterized by the following.