TW201611700A - Multilayer flexible circuit board and method for manufacturing same - Google Patents

Abstract

A multilayer flexible circuit board includes a first circuit board, an adhesive layer, and a second circuit board laminated in described order. The first circuit board includes a first connection pad. The second circuit board includes a second connection pad. The first connection pad is corresponding to the second connection pad. The first connection pad is coated by a first conductive paste. The adhesive layer includes an opening. The first connection pad and the second connection pad are arranged in the opening and electrically connected to the first conductive paste.

Description

Multilayer flexible circuit board and manufacturing method thereof

The invention relates to a multilayer flexible circuit board and a manufacturing method thereof.

Multi-layer flexible circuit boards are products of electronic technology that are developed in the direction of high speed, multi-function, large capacity and small volume. With the continuous development of electronic technology, especially the extensive and in-depth application of large-scale and ultra-large integrated circuits, multi-layer flexible circuit boards are rapidly developing toward high-density, high-precision, and layered words. At present, when manufacturing a multi-layer flexible circuit board, a through hole is formed by mechanical drilling or a blind hole is formed by laser etching, and then a via hole or a via hole is formed by electroplating, and then a conductive paste is filled in the via hole or the via hole, so that the conductive paste is filled in the via hole or the via hole. The interlayer lines are turned on to form a multilayer flexible circuit board.

In view of this, the present invention provides a multilayer flexible circuit board and a method of fabricating the same.

A method for fabricating a multilayer flexible circuit board, comprising the steps of: providing a first circuit board, the first circuit board comprising a first connection pad, the first connection pad being coated with a conductive paste; providing a second circuit board, the The second circuit board includes a second connection pad, the second connection pad corresponding to the first connection pad; a glue layer is provided, the glue layer includes an opening, the opening and the first connection pad and the Positioning the two connection pads; and sequentially pressing the first circuit board, the glue layer and the second circuit board, so that the first connection pad and the second connection pad are respectively disposed in the opening and electrically connected by the conductive paste Thereby forming a multilayer flexible circuit board.

A multi-layer flexible circuit board comprising a first circuit board, a glue layer and a second circuit board which are sequentially pressed together, the first circuit board includes a first connection pad, and the second circuit board includes a second connection pad, a second connection pad corresponding to the first connection pad, the first first connection pad is coated with a first conductive paste, the glue layer comprises an opening, and the first connection pad and the second connection pad are respectively disposed And electrically connected through the first conductive paste in the opening.

Compared with the prior art, the multi-layer flexible circuit board provided by the technical solution is formed by forming corresponding connecting pads on the circuit layers of the first circuit board and the second circuit board, and then applying a layer of conductive paste on the connection pads respectively. Then, the first circuit board and the second circuit board are bonded by a glue layer. During the pressing process, the corresponding connection pads are electrically connected through the conductive paste to electrically connect the circuit layers, and the method greatly reduces the manufacturing cost. The flexible circuit board of this embodiment can be used to fabricate a rigid-flex circuit board. In addition, in the manufacturing process of the technical solution, the first circuit board and the second circuit board can be simultaneously formed and directly subjected to a pressing process, so that the time and cost of manufacturing the circuit board can be greatly reduced.

1 is a schematic cross-sectional view of a flexible copper foil substrate according to an embodiment of the present invention.

2 is a schematic cross-sectional view showing the formation of a first connection pad on the flexible copper foil substrate of FIG. 1.

3 is a schematic cross-sectional view showing the formation of a conductive wiring layer and a first connection pad on the flexible copper foil substrate of FIG.

4 is a schematic cross-sectional view showing the application of a conductive paste on the first connection pad of FIG. 3 to form a first circuit board.

FIG. 5 is a cross-sectional view of a second circuit board provided by an embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of a rubber layer provided by an embodiment of the present invention.

7 is a schematic cross-sectional view showing a first flexible circuit board formed by pressing a first circuit board, a glue layer, and a second circuit board.

Embodiments of the present invention provide a method for fabricating a multi-layer flexible circuit board, including the steps of:

In the first step, referring to FIG. 4, a first circuit board 100 is provided.

The first circuit board 100 includes a first base layer 110, a first conductive circuit layer 111 and a second conductive circuit layer 112 formed on both sides of the first base layer 110, and a first surface formed on the surface of the first conductive circuit layer 111. The pad 130 is connected to the first conductive paste 140 formed on the surface of the first connection pad 130. The first circuit board 100 further includes a plurality of first via holes 121 electrically connected to the first conductive circuit layer 111 and the second conductive circuit layer 112.

The manufacturing steps of the first circuit board 100 are as follows:

First, referring to FIG. 1, a flexible copper foil substrate 11 is provided. The flexible copper foil substrate 11 includes a first base layer 110 and a first copper foil layer 101 and a second copper foil formed on both sides of the first base layer 110. Layer 102. The flexible copper foil substrate 11 further includes a plurality of first through holes 120.

In the embodiment, the first through hole 120 is formed on the flexible copper foil substrate 11 by drilling.

Next, referring to FIG. 2, a plurality of first connection pads 130 are formed on the first copper foil layer 101 by selective electroplating, and at the same time, the via holes 120 are plated on the hole walls of the through holes 120. A plurality of first via holes 121 are formed, and the first connection pads 130 protrude from the first copper foil layer 101.

Again, referring to FIG. 3, the first copper foil layer 101 and the second copper foil layer 102 are etched to form a first conductive wiring layer 111 and a second conductive wiring layer 112.

In this embodiment, during the etching process, the first copper foil layer 101 corresponding to the position of the first connection pad 130 is not etched.

Finally, referring to FIG. 4, a first conductive paste 140 is formed on the first connection pad 130 to form a first circuit board 100.

In the second step, referring to FIG. 5, a second circuit board 200 is provided. The second circuit board 200 includes a second substrate layer 210, a third conductive circuit layer 211 formed on both sides of the second substrate layer 210, and a fourth conductive layer. The circuit layer 212, the second connection pad 230 formed on the surface of the third conductive circuit layer 211, and the second conductive paste 240 formed on the surface of the second connection pad 230. The second circuit board 200 further includes a plurality of second via holes 221 electrically connected to the third conductive circuit layer 211 and the fourth conductive circuit layer 212.

The manufacturing process of the second circuit board 200 is similar to the manufacturing process of the first circuit board 100, and the first connection pads 130 and the second connection pads 230 are corresponding in position and the same size.

It can be understood that the first and second conductive pastes can be formed by coating or printing.

It can be understood that the first and second substrate layers may be flexible resin layers such as Polyimide (PI), Polyethylene Terephthalate (PET) or Polyethylene naphthalate. Polythylene Naphthalate (PEN) can also be a multilayer substrate. Of course, the second conductive paste may not be formed.

In the third step, referring to FIG. 6, a glue layer 300 is provided. The glue layer 300 includes an opening 320 corresponding to the positions of the first connection pad 130 and the second connection pad 230, and the same size.

In this embodiment, an opening 320 is formed on the adhesive layer 300 by means of punching or drilling or laser etching.

In the fourth step, referring to FIG. 7, the first circuit board 100, the adhesive layer 300, and the second circuit board 200 are laminated and laminated, and the first connection pad 130 and the second connection pad 230 are respectively disposed on the The first circuit board 100 and the second circuit board 200 are electrically connected to each other in the opening 320 and electrically connected by the conductive paste, thereby forming the multilayer flexible circuit board 10.

The glue layer 300 fills the first via hole 121 and the second via hole 221 after pressing.

It can be understood that the first circuit board 100 and the second circuit board 200 in the embodiment can be formed at the same time.

Referring to FIG. 7, an embodiment of the present invention further provides a multi-layer flexible circuit board 10, including:

a first circuit board 100, the first circuit board 100 includes a first base layer 110, first conductive circuit layers 111 and second conductive circuit layers 112 formed on opposite sides of the first base layer 110, and formed on the first conductive layer The first connection pad 130 on the surface of the circuit layer 111 is formed with the first conductive paste 140. The first circuit board 100 further includes a plurality of first via holes 121 electrically connected to the first conductive circuit layer 111 and the second conductive circuit layer 112.

a second circuit board 200, the second circuit board 200 includes a second base layer 210, third conductive circuit layers 211 and fourth conductive circuit layers 212 formed on opposite sides of the second base layer 210, and formed on the third conductive layer a second connection pad 230 on the surface of the circuit layer 211, the second connection pad 230 is formed on the third conductive circuit layer 211 and corresponds to the first connection pad 130, and the second connection pad 230 is coated with a second Conductive paste 240. The second circuit board 200 further includes a plurality of second via holes 221 electrically connected to the third conductive circuit layer 211 and the fourth conductive circuit layer 212.

The adhesive layer 300 is formed between the first circuit board 100 and the second circuit board 200. The adhesive layer 300 includes a plurality of openings 320, the opening 320 and the first connection pad 130. The first connection pad 130 and the second connection pad 230 are respectively disposed in the opening 320 and electrically connected through the conductive paste, and the glue layer 300 fills the first via hole 121. And a second via hole 221 .

Compared with the prior art, the multi-layer flexible circuit board provided by the technical solution is formed by forming corresponding connecting pads on the circuit layers of the first circuit board 100 and the second circuit board 200, and then coating a layer on the connection pads respectively. The conductive paste 140 is further bonded to the first circuit board 100 and the second circuit board 200 by a glue layer. During the pressing process, the corresponding connection pads are electrically connected through the conductive paste 140 to electrically connect the circuit layers, and the method is greatly reduced. The production cost. In addition, in the manufacturing process of the present technical solution, the first circuit board 100 and the second circuit board 200 can be simultaneously formed and directly subjected to a pressing process, so that the time and cost of manufacturing the circuit board 100 can be greatly reduced.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. However, the above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art will be covered by the following claims.

10‧‧‧Multilayer flexible circuit board

11‧‧‧Soft copper foil substrate

100‧‧‧First board

101‧‧‧First copper foil layer

102‧‧‧Second copper foil layer

110‧‧‧First basal layer

111‧‧‧First conductive circuit layer

112‧‧‧Second conductive circuit layer

120‧‧‧First through hole

121‧‧‧First via

130‧‧‧First connection pad

140‧‧‧First conductive paste

200‧‧‧second board

210‧‧‧Second basal layer

211‧‧‧ Third conductive circuit layer

212‧‧‧fourth conductive layer

220‧‧‧second through hole

221‧‧‧Second via

230‧‧‧Second connection pad

240‧‧‧Second conductive paste

300‧‧ ‧ adhesive layer

320‧‧‧ openings

no

110‧‧‧First basal layer

111‧‧‧First conductive circuit layer

112‧‧‧Second conductive circuit layer

121‧‧‧First via

130‧‧‧First connection pad

140‧‧‧First conductive paste

210‧‧‧Second basal layer

211‧‧‧ Third conductive circuit layer

212‧‧‧fourth conductive layer

221‧‧‧Second via

230‧‧‧Second connection pad

240‧‧‧Second conductive paste

300‧‧ ‧ adhesive layer

320‧‧‧ openings

10‧‧‧Multilayer flexible circuit board

Claims (10)

A method for manufacturing a multilayer flexible circuit board, comprising the steps of:
Providing a first circuit board, the first circuit board includes a first connection pad, and the first connection pad is coated with a conductive paste;
Providing a second circuit board, the second circuit board including a second connection pad, the second connection pad corresponding to the first connection pad;
Providing a glue layer, the glue layer includes an opening corresponding to the positions of the first connection pad and the second connection pad; and sequentially pressing the first circuit board, the glue layer and the second circuit board to make The first connection pad and the second connection pad are respectively disposed in the opening and electrically connected by a conductive paste to form a plurality of flexible circuit boards. The method of fabricating a multi-layer flexible circuit board according to claim 1, wherein the first circuit board comprises a first base layer and a first conductive circuit layer and a second conductive circuit layer formed on opposite sides of the first base layer, The first connection pad is formed on a surface of the first conductive circuit layer. The method for fabricating a multi-layer flexible circuit board according to claim 1, wherein the manufacturing method of the first circuit board comprises the steps of:
Providing a flexible copper foil substrate, the flexible copper foil substrate comprising a first substrate layer and a first copper foil layer and a second copper foil layer formed on both sides of the first substrate layer;
Forming a plurality of first connection pads on the first copper foil layer by selective plating;
Forming a first conductive wiring layer and a second conductive wiring layer by forming a first copper foil layer and a second copper foil layer; and coating a conductive paste on the first connection pad to form a first circuit board. The method of fabricating a multilayer flexible circuit board according to claim 1, wherein the first circuit board and the second circuit board are simultaneously formed. The method of fabricating a multilayer flexible circuit board according to claim 1, wherein a second conductive paste is formed on the second connection pad, and the first connection pad and the second connection pad pass the first conductive paste and the second conductive paste. connection. The method of fabricating a multilayer flexible circuit board according to claim 5, wherein the first and second conductive pastes are formed by coating or printing. The method of fabricating a multi-layer flexible circuit board according to claim 1, wherein the first circuit board further includes a plurality of first via holes, and the second circuit board includes a plurality of second via holes, and the adhesive layer is filled. Filling the first via hole and the second via hole. The method of fabricating a multilayer flexible circuit board according to claim 1, wherein the second circuit board further comprises a second base layer and third conductive circuit layers and fourth conductive circuit layers formed on opposite sides of the second base layer The second connection pad is formed on a surface of the third conductive circuit layer. The method of fabricating a multilayer flexible circuit board according to claim 8, wherein the opening is the same size as the first connection pad and the second connection pad. A multi-layer flexible circuit board comprising a first circuit board, a glue layer and a second circuit board which are sequentially pressed together, the first circuit board includes a first connection pad, and the second circuit board includes a second connection pad, a second connection pad corresponding to the first connection pad, the first first connection pad is coated with a first conductive paste, the glue layer comprises an opening, and the first connection pad and the second connection pad are respectively disposed And electrically connected through the first conductive paste in the opening.