JP2009010094A - Flexible printed circuit board and lead disconnection processing method thereof - Google Patents

Abstract

The present invention provides a lead disconnection processing method for plating of a flexible printed circuit board, in which the process of only disconnection processing of a lead portion for plating is simple and the disconnection processing of the lead portion for plating can be performed at low cost.
A plating lead portion is provided together with a circuit pattern portion on one surface of an insulating base layer, and a disconnection hole is formed through the insulating base layer and the plating lead portion to disconnect the plating lead portion. The adhesive 6 is applied to the other surface of the insulating base layer 2 and includes the area of the disconnection hole 14, the reinforcing plate 7 is disposed on the surface to which the adhesive 6 has been applied, and the reinforcing plate 7 is connected to the insulating base. The layer 2 is subjected to pressure and heat treatment, and the adhesive 6 is oozed into the insulating hole 14 in the course of the pressure and heat treatment, and the disconnection hole 14 is sealed with the oozed adhesive 6.
[Selection] Figure 3

Description

  The present invention relates to a flexible printed circuit board in which a lead portion for plating is subjected to disconnection processing and a lead disconnection processing method for the plating.

  As shown in FIG. 7, the flexible printed circuit board 100 subjected to the electrolytic plating process is provided with a lead portion 102 for plating in addition to the circuit pattern portions 101a, 101b, and 101c. The plating lead portion 102 needs to be subjected to a disconnection process after the electrolytic plating process, that is, a plating lead portion disconnection process.

  As a plating lead disconnection processing method of the conventional example, as shown in FIG. 8, a disconnection hole 103 for disconnecting the plating lead 102 is provided in the flexible printed circuit board 100. Then, as shown in FIGS. 9 and 10, the section of the circuit pattern portion 102 is exposed by the disconnection hole 103, and there is a possibility that the plating lead portions 103 separated by corrosion, soldering iron, copper plating, etc. may be short-circuited. There is a method of sealing the disconnection hole 103 by applying a resin (see Patent Document 1). 7 to 10, reference numeral 104 denotes an insulating base layer, 105 denotes a coverlay layer, and 106 denotes a plating electrode position.

Further, as another conventional lead cutting method for plating, the coverlay layer (solder resist layer) covering the plating lead 103 is removed with a laser, and then the exposed plating lead 103 is etched. There is a method of removing (see Patent Document 2).
JP 2004-153035 A JP 2004-183043 A

  However, in the former conventional example, not only a process of forming the disconnection hole 103 in the flexible printed circuit board 100 but also a process of applying a resin to the disconnection hole 103 is required, which complicates the process and increases costs accordingly. There is a problem.

  In the latter conventional example, a laser irradiation process for removing the cover lay and an etching process for removing the lead portion for plating are required. As in the former conventional example, the process becomes complicated and the cost increases accordingly. There is a problem.

  Accordingly, an object of the present invention is to provide a flexible printed circuit board that can easily perform the disconnection processing of the plating lead portion at a low cost, and a plating lead disconnection processing method that is simple in the process of disconnecting the plating lead portion. To do.

  According to the first aspect of the invention for achieving the above object, a plating lead portion is provided together with a circuit pattern portion on one surface of an insulating base layer, penetrates the insulating base layer and the plating lead portion, and the plating lead portion is disconnected. The flexible printed circuit board is characterized in that a disconnection hole is provided, and the disconnection hole is sealed with an adhesive that adheres a reinforcing plate to the insulating base layer.

  According to a second aspect of the present invention, a lead portion for plating is provided together with a circuit pattern portion on one surface of the insulating base layer, and a disconnection hole is provided through the insulating base layer and the plating lead portion to disconnect the lead portion for plating. The other surface of the insulating base layer, and applying an adhesive to a range including the location of the disconnection hole or laminating a sheet-like adhesive, placing a reinforcing plate on the surface to which the adhesive is applied, The reinforcing plate is pressed and heat-treated on the insulating base layer, and the adhesive is oozed out into the insulating hole during the pressurizing and heat-treating process, and the disconnection hole is sealed with the oozed adhesive. It is a lead disconnection processing method for plating of a flexible printed circuit board characterized by stopping.

  According to the first aspect of the present invention, if only the step of forming the disconnection hole is performed as the disconnection process of the plating lead portion, the disconnection hole is formed by the adhesive in the step of attaching the reinforcing plate via the adhesive. Sealed. Therefore, the process of only the disconnection process of the plating lead part is simple, and the disconnection process of the plating lead part can be performed at low cost.

  According to the second aspect of the present invention, since only the process of forming the disconnection hole is sufficient as the process for disconnecting the lead part for plating, the disconnection process of the lead part for plating can be performed at a low cost with a simple process.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 to 5 show an embodiment of the present invention, FIG. 1 is a plan view of a principal part of a flexible printed board, FIG. 2 is an enlarged view of a part of FIG. 1, and FIG. 3 is a line AA in FIG. 4 is a cross-sectional view of a main part showing a state in which a disconnection hole is opened, FIG. 5 is a cross-sectional view of the reinforcing plate attaching process before pressurization and heating, and FIG. 6 is a drawing of the reinforcing plate attaching process. It is sectional drawing which shows a pressure and after a heating.

  As shown in FIGS. 1 to 3, the flexible printed circuit board 1 includes an insulating base layer 2 made of, for example, a polyimide film, a circuit pattern portion 3 and a plating lead portion 4 provided on one surface of the insulating base layer 2, and A coverlay layer 5 provided on the upper surface of the insulating base layer 2 so as to cover the circuit pattern portion 3 and the plating lead portion 4, and a region including the location of the disconnection hole 14 described below on the lower surface of the insulating base layer 2. An adhesive 6 provided and a reinforcing plate 7 attached to the lower surface of the insulating base layer 2 through the adhesive 6 are provided.

  The circuit pattern unit 3 includes a first signal pattern 10, a second signal pattern 11, a third signal pattern 12, and the like. The first component electrodes 10 a and 10 a ′ are provided at one end of the first signal pattern 10 and one end of the second signal pattern 11, and the second electrode is connected to the other end of the second signal pattern 11 and one end of the third signal pattern 12. Component electrodes 10b and 10b 'are provided.

  The plating lead portion 4 connects between the first signal pattern 10 and the second signal pattern 11. The plating lead portion 4 is for setting the first component electrode 10a and the second component electrode 10b as negative electrodes when the first signal pattern 10 is set to the plating electrode position 13.

  The coverlay layer 5 is removed for electrolytic plating in the region of the first component electrodes 10a and 10a 'and the second component electrodes 10b and 10b'.

  The flexible printed circuit board 1 is provided with a disconnection hole 14 that penetrates the insulating base layer 2, the plating lead portion 4, and the coverlay layer 5 and disconnects the plating lead portion 4. The disconnection hole 14 is sealed with an adhesive 6 that adheres the reinforcing plate 7 to the insulating base layer 2.

  The adhesive 6 is, for example, an acrylic type that melts at a high temperature and solidifies at a low temperature.

  The reinforcing plate 7 is provided in order to protect a mounting component such as an electronic component by preventing a solder crack caused by a bending stress. The reinforcing plate 7 is made of glass epoxy resin, polyimide resin, aluminum, or SUS having a thickness of about 0.2 mm to 2 mm.

  Next, steps related to the lead disconnection process for plating of the flexible printed circuit board 1 will be described with reference to FIGS. When the electroplating process for performing electroplating on the first and second component electrodes 10a, 10a'10b, 10b 'is completed, first, at the position where the lead plating portion 4 is disconnected, the insulating base layer 2 and the plating lead A disconnection hole 14 that penetrates the portion 4 and the coverlay layer 5 is formed. Next, as shown in FIG. 5, the adhesive 6 is applied to the lower surface of the insulating base layer 2, the reinforcing plate 7 is disposed on the lower surface of the adhesive 6, and the flexible printed circuit board 1 disposed in this order is pressed. Set to 20. And as shown in FIG. 6, the flexible printed circuit board 1 is pressurized and heated with the press machine 20. As shown in FIG. The adhesive 6 is melted by heating, and the melted adhesive 6 oozes into the open hole 14 by pressurization. The adhesive 6 that has oozed out into the disconnection hole 14 is solidified by a decrease in temperature. Thus, the disconnection hole 14 is sealed with the adhesive 6 that has oozed out.

  As described above, according to the present invention, if only the step of forming the disconnection hole 14 is performed as the disconnection process of the plating lead portion 4, the disconnection hole 14 is a step of attaching the reinforcing plate 7 with the adhesive 6. Is sealed by the adhesive 6. Therefore, the process of only the disconnection process of the plating lead part 4 is simple, and the disconnection process of the plating lead part 4 can be performed at low cost.

  In the above embodiment, the adhesive 6 is applied to the lower surface of the insulating base layer 2, but a sheet-like adhesive may be laminated on the lower surface of the insulating base layer 2.

It is a principal part top view of the flexible printed circuit board concerning one embodiment of the present invention. It is an enlarged view of the a part of FIG. It is the sectional view on the AA line of FIG. It is principal part sectional drawing which shows the state which opened the disconnection hole. It is principal part sectional drawing which shows the pressurization and heating before a sticking process of a reinforcement board. It is principal part sectional drawing which shows the pressurization and heating of a sticking process of a reinforcement board. It is a principal part top view for demonstrating a prior art example and demonstrating the electrolytic plating process of a flexible printed circuit board. It is a principal part sectional drawing of the flexible printed circuit board which showed the prior art example and formed the disconnection hole. It is the b section enlarged view of FIG. FIG. 10 is a sectional view taken along line B-B in FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible printed circuit board 2 Insulation base layer 3 Circuit pattern part 4 Lead part for plating 6 Adhesive 7 Reinforcement board 14 Disconnection hole

Claims (2)

  A lead portion for plating is provided on one surface of the insulating base layer together with a circuit pattern portion, a disconnection hole is provided to penetrate the insulating base layer and the lead portion for plating, and the lead portion for plating is disconnected, and the disconnection hole is reinforced. A flexible printed circuit board, wherein a plate is sealed with an adhesive that adheres to the insulating base layer. A lead portion for plating is provided on one surface of the insulating base layer together with a circuit pattern portion, a disconnection hole is provided to penetrate the insulating base layer and the lead portion for plating, and to disconnect the lead portion for plating,
Applying an adhesive or laminating a sheet-like adhesive on the other surface of the insulating base layer and including the location of the disconnection hole, placing a reinforcing plate on the surface to which the adhesive is applied, Pressurizing and heat-treating a reinforcing plate on the insulating base layer, causing the adhesive to bleed into the insulating hole during the pressurizing and heat-treating process, and sealing the disconnection hole with the oozed adhesive A lead disconnection processing method for plating a flexible printed circuit board.

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