TWI531288B - Flexible printed circuit board with gold fingers and method for manufacturing same - Google Patents

Description

Flexible circuit board with gold fingers and manufacturing method thereof

The present invention relates to the field of circuit boards, and in particular, to a circuit board having a gold finger and a method of fabricating the same.

A conventional flexible circuit board includes a plurality of gold fingers, such as a zero insertion force (ZIF) connector, for electrically conducting with an external electronic device. Since a product with a gold finger usually requires multiple insertions of gold fingers during use, the surface material of the gold finger is usually gold, and the gold material on the surface of the gold finger is usually made by electroplating. When electroplating gold is performed, the end of the gold finger needs to be led out with a gold-plated lead connected to the negative pole of a power source, and the gold-plated lead is broken after the end of the electroplating gold. In order to ensure the gold-plated surface of the gold finger surface is complete, the gold-plated lead wire will partially remain on the gold finger. During the use of the gold finger, the gold-plated lead wire remaining on the gold finger will have the risk of peeling off and falling, resulting in gold. The quality of the fingers is poor. In addition, when the gold-plated lead is broken, the gold-plated lead may be cracked and warped.

Therefore, it is necessary to provide a high-quality flexible circuit board with a gold finger and a manufacturing method thereof.

A method for manufacturing a flexible circuit board, comprising the steps of: providing a flexible circuit substrate, a package a base layer, a first conductive layer formed on a surface of the base layer, and a first cover film formed on the first conductive layer, the flexible circuit substrate including a product area and a waste area formed around the product area, the first conductive layer The portion located in the product area includes a plurality of gold finger bases, a ground pad, a first lead and a third lead, and a part of the plurality of gold finger bases is directly electrically connected to the ground pad, and the remaining part of the gold finger base and the first lead are Correspondingly, the remaining portion of the gold finger base is electrically connected to the ground pad through a corresponding first lead; the portion of the first conductive layer located in the scrap area is a conductive copper foil layer, and the two ends of the third lead are respectively Connecting the ground pad and the conductive copper foil layer, the first cover film is formed with an opening, the plurality of gold finger bases are exposed in the opening; and the conductive copper foil layer of the flexible circuit substrate is connected to the negative electrode of the power source Electroplating is performed in a plating bath having a gold plating solution, and a gold plating layer is respectively formed on the plurality of gold finger bases, and the plurality of gold fingers and the gold plating layer formed on the surface thereof form a complex Goldfinger; between the conductive copper foil layer and the third lead is disconnected, and cut off the lead connecting each of the first ground pad; and removing the waste region to form a flexible circuit board having a plurality of gold fingers.

A flexible circuit board includes a base layer, a first conductive layer formed on one side of the base layer, and a first cover film formed on the first conductive layer. The first conductive layer includes a plurality of gold finger bases, a ground pad, a plurality of first connecting wires, and a lead connecting pad corresponding to the first connecting wires. The first cover film is provided with an opening, the plurality of gold finger bases are exposed in the opening, the flexible circuit board further comprises a gold plating layer formed on the surface of the plurality of gold finger bases, the plurality of gold finger bases being combined with the gold plating layer on the surface thereof Compose a plurality of gold fingers. The number of the first connecting wires is less than the number of the gold finger bases, the end of each first connecting wire is connected to a gold finger base, the other end is connected to the corresponding lead connecting pad, and the remaining gold finger base is electrically connected to the ground. pad.

Compared with the prior art, in the method of fabricating the flexible circuit board, when the gold plating layer is formed, the gold plating lead is a part of the first conductive layer, the gold plating lead is cut after the gold plating layer is formed, and the residual gold plating lead is located on the first conductive layer. Inside, that is, there is no residual gold-plated lead on the gold finger, thereby avoiding the risk of the gold-finger performance quality caused by cracking, buckling and peeling of the gold-plated lead, thereby improving the product quality of the flexible circuit board. In addition, the flexible circuit board can also be applied to a rigid-flex board.

10‧‧‧Flexible circuit board

11‧‧‧ basal layer

12‧‧‧First conductive layer

13‧‧‧Second conductive layer

14‧‧‧First cover film

15‧‧‧second cover film

16‧‧‧ reinforcing plate

102‧‧‧Product Area

104‧‧‧Residual area

122‧‧‧Gold finger base

123‧‧‧First connecting wire

124‧‧‧Second connecting wire

125‧‧‧ lead connection pad

126‧‧‧First lead

127‧‧‧second lead

128‧‧‧ Third lead

129‧‧‧ Grounding mat

121‧‧‧ Conductive copper foil area

17‧‧‧First Intersection Area

18‧‧‧Second intersection

142‧‧‧ openings

19‧‧‧ gold plating

20‧‧‧ Gold Finger

100‧‧‧Flexible circuit board

1 is a top plan view of a flexible circuit substrate according to an embodiment of the present invention.

2 is a cross-sectional view of the flexible circuit substrate of FIG. 1.

3 is a schematic structural view of a first conductive layer of the flexible circuit substrate of FIG. 1.

4 is a cross-sectional view showing a gold finger formed on a gold finger base of the flexible circuit board of FIG. 1 after gold is formed.

FIG. 5 is a schematic view showing the structure of a first conductive layer after the gold-plated lead of the flexible circuit substrate of FIG. 1 is broken.

6 is a schematic structural view of a first conductive layer of a flexible circuit board formed after removing a waste region of the flexible circuit substrate of FIG. 4.

Referring to FIG. 1 to FIG. 6 , an embodiment of the present invention provides a method for fabricating a flexible circuit board having a gold finger, including the following steps:

In the first step, referring to FIG. 1 to FIG. 3, a flexible circuit substrate 10 is provided.

The flexible circuit substrate 10 is a circuit board on which conductive lines are formed. In the present embodiment, the flexible circuit substrate 10 is a double-sided circuit board. The flexible circuit substrate 10 includes a base layer 11, The first conductive layer 12, the second conductive layer 13, the first cover film 14, the second cover film 15, and a reinforcing plate 16. The base layer 11 is a flexible resin layer such as Polyimide (PI), Polyethylene Terephthalate (PET) or Polythylene Naphthalate (PEN). . The first conductive layer 12 and the second conductive layer 13 are respectively formed on opposite sides of the base layer 11. The first cover film 14 and the second cover film 15 are respectively formed on the first conductive layer 12 and the second conductive layer. The reinforcing plate 16 is formed on the second cover film 15 at 13.

The flexible circuit substrate 10 includes a product area 102 and a waste area 104 that forms a perimeter of the product area 102. The first conductive layer 12 located in the product area 102 includes a plurality of gold finger bases 122, a plurality of first connection wires 123, a second connection wire 124, a plurality of lead connection pads 125, a plurality of first leads 126, and two second leads. 127. A third lead 128 and two ground pads 129. The portion of the first conductive layer 12 located in the waste region 104 is a conductive copper foil region 121. The first conductive layer 12 can be formed by etching a copper foil layer.

The plurality of gold finger bases 122 are respectively elongated and linearly arranged at one end of the product area 102. In this embodiment, the plurality of gold finger bases 122 includes thirteen gold finger bases 122 arranged in a staggered length. The outermost four gold finger bases 122 on one side of the thirteen gold finger bases 122, the outermost four gold finger bases 122 on the opposite side, and the middle gold finger base 122 are ground terminals, and the rest The four gold finger bases 122 are non-ground terminals. One end of the eight gold finger bases 122 as ground terminals on both sides is directly connected to the ground pad 129, and the gold finger base 122 as a ground terminal in the middle is electrically connected to the ground pad 129 through the second connection wire 124. a gold finger base 122 as a non-ground terminal and the first connection wire 123 and the lead connection pad 125 respectively Correspondingly, the gold finger bases 122, which are non-ground terminals, are respectively connected to the corresponding lead connection pads 125 through the corresponding first connecting wires 123. The first lead 126 is in one-to-one correspondence with the lead connecting pad 125, that is, four, and is respectively connected to and drawn out from the corresponding lead connecting pad 125, wherein one end of the two first leads 126 and one of the second leads 127 are One ends are connected such that the two first leads 126 and the connected second leads 127 intersect the first intersecting region 17; one ends of the other two first leads 126 are connected to one end of the other second lead 127, intersecting The dots constitute a second intersecting region 18. The other ends of the two second leads 127 are connected to the ground pad 129, so that the gold finger base 122 as a non-connecting terminal is electrically connected to the ground pad 129. The two ends of the third lead 128 are respectively connected to the ground pad 129 and the conductive copper foil region 121 of the scrap region 104, so that the plurality of gold finger bases 122 are electrically connected to the conductive copper foil region 121 of the scrap region 104. It should be noted that the portion of the first conductive layer 12 located in the product region 102 further includes a conductive line, which is not shown in FIGS. 1 and 2. It can be understood that the plurality of gold finger bases 122 can also be equal in length.

The portion of the second conductive layer 13 located in the product region 102 includes a conductive trace, and the portion of the second conductive layer 13 located in the scrap region 104 is a conductive copper foil region (not labeled). The reinforcing plate 16 is equal to or slightly larger than the overall size of the plurality of gold finger bases 122, and the reinforcing plate 16 is opposite to the position of the plurality of gold finger bases 122. The reinforcing plate 16 is opposite to the position of the plurality of gold finger bases 122. It is used to strengthen the hardness of the region of the plurality of gold finger bases 122 to facilitate the insertion and removal of the plurality of gold fingers.

The first cover film 14 covers the first conductive layer 12, and the second cover film 15 covers the second conductive layer 13. The first cover film 14 is provided with an opening 142, and the plurality of gold finger bases 122 are exposed to the opening 142.

It can be understood that in actual products, the number of gold finger bases 122 is not limited to The thirteenth embodiment may be more than or less than thirteen; the number of the gold finger base 122 corresponding to the ground terminal is not limited to the embodiment, as long as the gold finger base 122 corresponding to the ground terminal The ends are directly connected to the ground pad 129 or directly connected by a connecting wire. Accordingly, the gold finger base 122 corresponding to the non-grounding end is not limited to four of the embodiment. It can also be understood that the two lead connection pads 125 can also be omitted, and the first connecting wire 123 is directly connected to the end of the second lead 127, or the first connecting wire 123 is directly connected to the ground pad 129. A connecting wire 123 simultaneously corresponds to the first connecting wire 123 being directly connected to the corresponding first lead 126. In addition, the number of the first leads 126 connected to each of the second leads 127 may also be greater than two. For example, the four first leads 126 of the embodiment may be connected to the ends of one of the second leads 127, and the other A second lead 127 can be omitted. The number of the second leads 127 may also be increased or decreased as needed, and is not limited to the embodiment.

The flexible circuit substrate 10 of the present embodiment is a two-layer circuit substrate, that is, includes two layers of conductive circuit layers. It can be understood that the flexible circuit substrate 10 can also be a single-layer circuit substrate or a multilayer circuit substrate having more than two layers of conductive circuit layers. It is not limited to this embodiment.

In the second step, referring to FIG. 4, the surface of the plurality of gold finger bases 122 is plated with gold to form a gold plating layer 19, thereby forming a plurality of gold fingers 20. The plurality of gold fingers 20 includes the plurality of gold finger bases 122 and a gold plating layer 19 on the surface thereof.

The method of gold plating the surface of the plurality of gold finger bases 122 to form the gold plating layer 19 is as follows: connecting the conductive copper foil region 121 of the first conductive layer 12 to a negative electrode of a power source (not shown), and connecting the flexible circuit substrate 10 is disposed in a plating bath (not shown) having a gold ion plating solution to form a gold plating layer 19 on the surface of the plurality of gold finger substrates 122 by electroplating. Since the plurality of gold finger bases 122 are electrically connected to the conductive copper foil region 121, each gold finger base 122 can form a gold plating layer 19. The plating solution can be a plating solution used in a conventional electroplating gold process.

In the third step, referring to FIG. 5, the first intersecting region 17, the second intersecting region 18 and the third lead 128 are cut off to disconnect the plurality of second leads 127 and the two first leads 126 from each other. The third lead 128 is disconnected from the conductive copper foil region 121. The method of cutting the first intersecting region 17, the second intersecting region 18, and the third lead 128 may be die cutting, laser cutting, or the like.

In a fourth step, referring to FIG. 6, the waste area 104 is removed to obtain a flexible circuit board 100 including a product area 102. The method of removing the waste area 104 may be one or more die-cutting along the boundary of the product area 102 and the waste area 104, or may be a method of laser cutting.

It can be understood that when the first connecting wire 123 is directly connected to the ground pad 129, each of the first connecting wires 123 needs to be punched when punching.

It should be noted that, before the waste area 104 is removed, the step of improving the electrical performance test of the flexible circuit substrate 10 on which the gold fingers 20 are formed is usually included.

The flexible circuit board 100 of the present embodiment includes a base layer 11, a first conductive layer 12, a second conductive layer 13, a first cover film 14, a second cover film 15, and a reinforcing plate 16. The first conductive layer 12 and the second conductive layer 13 are respectively formed on opposite sides of the base layer 11. The first cover film 14 and the second cover film 15 are respectively formed on the first conductive layer 12 and the second conductive layer. The reinforcing plate 16 is formed on the second cover film 15 at 13. The second conductive layer 13 includes a plurality of gold finger bases 122, a ground pad 129, a first connecting wire 123, and a lead connection pad 125. The first cover film 14 has an opening 142. The plurality of gold finger bases 122 are exposed to the opening 142. The flexible circuit board 100 further includes a gold plating layer 19 disposed on the surface of each of the gold finger bases 122. The plurality of gold finger bases 122 and its The gold-plated layers 19 on the surface collectively constitute a plurality of gold fingers 20. The plurality of gold finger bases 122 includes a grounding terminal and a non-grounding terminal. The grounding terminal is electrically connected to the grounding pad 129. The first connecting wire 123 is in one-to-one correspondence with the non-grounding terminal and the lead connecting pad 125. The first connecting wire 123 One end is connected to the corresponding first connecting wire 123, and the other end is connected to the corresponding lead connecting pad 125, respectively. The reinforcing plate 16 is opposite to the position of the plurality of gold fingers 20 for reinforcing the hardness of the plurality of gold fingers 20 to facilitate the insertion and removal of the plurality of gold fingers 20.

Compared with the prior art, in the method for fabricating the flexible circuit board of the present embodiment, when the gold plating layer 19 is formed, the gold plating lead is a part of the first conductive layer 12, and is formed simultaneously with the conductive line when the first conductive layer 12 is formed, and the gold plating lead is formed. That is, the first lead 126, the second lead 127, and the third lead 128 are cut after the gold plating layer 19 is formed, and the remaining gold-plated lead is located in the first conductive layer 12, that is, the gold finger 20 has no residual gold-plated lead, thereby avoiding The risk of the quality of the gold finger performance caused by the cracking, the warping of the gold-plated lead wire and the peeling off, thereby improving the product quality of the flexible circuit board 100. In addition, the flexible circuit board 100 of the present embodiment can also be applied to a rigid-flex board.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application in this case. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

102‧‧‧Product Area

123‧‧‧First connecting wire

124‧‧‧Second connecting wire

125‧‧‧ lead connection pad

129‧‧‧ Grounding mat

20‧‧‧ Gold Finger

100‧‧‧Flexible circuit board

Claims (7)

A manufacturing method of a flexible circuit board, comprising the steps of: providing a flexible circuit substrate comprising a base layer, a first conductive layer formed on a surface of the base layer, and a first cover film formed on the first conductive layer, the flexible circuit substrate comprising a product And a waste area formed around the product area, the portion of the first conductive layer located in the product area includes a plurality of gold finger bases, a ground pad, a first lead and a third lead, and a part of the plurality of gold finger bases and the ground pad Directly electrically connecting, the remaining part of the gold finger base corresponds to the first lead one by one, and the remaining part of the gold finger base is electrically connected to the ground pad through a corresponding first lead; the first conductive layer is located in the scrap area The portion of the third lead is connected to the ground pad and the conductive copper foil layer, and the first cover film is formed with an opening, and the plurality of gold finger bases are exposed in the opening; The conductive copper foil layer of the flexible circuit substrate is connected to the negative electrode of the power source and then disposed in a plating bath having a gold plating solution for electroplating, and is divided on the plurality of gold finger substrates. Forming a gold plating layer, the plurality of gold fingers together with the gold plating layer formed on the surface thereof constitute a plurality of gold fingers; disconnecting the third lead from the conductive copper foil layer, and cutting off the connection of each of the first leads and the ground pad; And removing the waste area to form a flexible circuit board having a plurality of gold fingers. The manufacturing method of the flexible circuit board of claim 1, wherein the flexible circuit substrate further comprises a second conductive layer, a second cover film and a reinforcing plate sequentially formed on opposite sides of the base layer, the second The conductive layer includes a conductive line in a portion of the product area, the cover film is for protecting the second conductive layer, and the reinforcing plate is disposed opposite to the plurality of gold finger bases for reinforcing the hardness of the plurality of gold finger base regions. The method of fabricating a flexible circuit board according to claim 1, wherein the first conductive layer is further packaged The at least one second lead has one end connected to the ground pad, and the other end of the at least one second lead is connected to an end of each of the first lead away from the gold finger base. The method of fabricating a flexible circuit board according to claim 3, wherein the method of disconnecting the third lead from the conductive copper foil layer and cutting off the connection between each of the first leads and the ground pad is: The die cutting method cuts the third lead and breaks the intersection of the at least one second lead with each of the first leads. The method of manufacturing the flexible circuit board of claim 3, wherein the first conductive layer further comprises a first connecting wire and a lead connecting pad, wherein the first connecting wire and the lead connecting pad are in one-to-one correspondence with the first lead One end of each of the first leads away from the ground pad is connected to a corresponding lead connection pad, and two ends of each of the first connection wires are respectively connected to a corresponding gold finger base and a corresponding lead connection pad. The method of fabricating a flexible circuit board according to claim 4, wherein each of the at least one second lead is connected to the plurality of first leads. The method of fabricating a flexible circuit board according to claim 4, wherein one end of the plurality of gold finger bases directly connected to the ground pad is directly connected to the ground pad or electrically connected to the ground pad through the second connecting wire.