TW201818792A - Hollowed printed circuit board and method for manufacturing same - Google Patents

Abstract

The present invention relates to a method for manufacturing a flexible printed circuit board. The method includes steps as follows: providing a copper foil wrapped on a first roller, and the copper foil includes a first surface and a second surface opposite to the first surface; coating a layer of liquid photosensitive resin, and the liquid photosensitive resin is used to form a first insulating base layer; forming a conducting circuit layer using the copper foil, and the conducting circuit layer comprising a conducting circuit pattern and gaps between the conducting circuit pattern; forming a second insulating base layer on the other surface of the conducting circuit layer, and the second insulating base layer being filled the gaps; cutting the conducting circuit layer to obtain a plurality of flexible printed circuit boards, and each flexible printed circuit board includes a conductive circuit layer, a first insulating layer and a second insulating layer formed on opposite sides of the conductive circuit layer.

Description

Hollow circuit board and manufacturing method thereof

The invention relates to a manufacturing method of a hollow circuit board and a hollow circuit board obtained by the manufacturing method.

Hollow circuit boards, also commonly referred to as embossed boards, refer to circuit boards where the insulating layers on both sides of conductive lines in some areas have been hollowed out, so that the lines are suspended on both sides. The conductive lines in the hollowed out area can realize double-sided electrical connection. In the prior art, the process of producing a hollow circuit board is as follows: providing copper foil; cutting the copper foil into sheets; providing an insulating layer with a window; cutting the insulating layer into sheets; manually attaching the insulating layers one by one Onto the copper foil; then press and bake the insulation layer. In this way, the alignment of the windows of the two insulation layers on the opposite surfaces of the copper foil is prone to large errors, which affects the accuracy of the position of the exposed circuit. , Which makes it difficult to guarantee the quality of the hollow printed circuit board, and the process is tedious and wastes manpower.

In view of this, it is necessary to provide a flexible circuit board manufacturing method capable of solving the above technical problems and a flexible circuit board manufactured by the method.

A method for manufacturing a flexible circuit board includes the following steps:

Providing a copper foil wound on a first reel, rolling out the copper foil from the first reel, the copper foil having a first surface and a second surface opposite to the first surface;

Coating a layer of a liquid photosensitive resin material on the first surface to form the first insulating base material layer of the liquid photosensitive resin material;

Fabricating the copper foil to form a conductive circuit layer, the conductive circuit layer including a plurality of conductive patterns and a gap formed between the conductive patterns;

A layer of liquid photosensitive resin material is coated on the second surface, and the liquid photosensitive resin material forms a second insulating base material layer. The second insulating base material layer covers the conductive patterns and fills the gaps with the first insulating base. Material layers collectively cover the conductive patterns; and

The conductive patterns covered by the first insulating base material layer and the second insulating base material layer are separated and separated to obtain a plurality of flexible circuit boards. Each flexible circuit board includes a conductive circuit layer and a conductive circuit layer. A first insulating base material layer and a second insulating base material layer on opposite surfaces.

A flexible circuit board includes a conductive circuit layer, an insulating substrate layer and two second insulating substrate layers located on opposite surfaces of the conductive circuit layer, the first insulating substrate layer and the second insulating substrate layer. It is formed by coating a liquid photosensitive resin material on two opposite surfaces of the conductive circuit layer and curing them.

Compared with the prior art, the hollow-type flexible circuit board provided by the present invention and a manufacturing method thereof make a plurality of hollow-type flexible circuit boards in a continuous operation mode of roll-to-roll, which saves the time and cost of making hollow-type flexible circuit boards. Manpower improves production efficiency. Secondly, the first insulating substrate layer and the second insulating substrate layer covered on the surface of the conductive circuit layer are made of a photosensitive resin material, that is, there is no adhesive layer on the surface of the conductive circuit layer. The thickness of the circuit board is reduced, and the impedance for transmitting optical signals can also be reduced. The first opening and the second opening included in the hollow circuit board are made by exposing and developing the first insulating substrate layer and the second insulating substrate layer. Therefore, the alignment accuracy of the first opening and the second opening is improved, thereby improving the quality of the hollow circuit board.

FIG. 1 is a cross-sectional view of a copper foil wound on a first reel according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of forming a layer of a liquid photosensitive resin material on one surface of the copper foil, and forming the liquid photosensitive resin material into a first insulating base material layer.

FIG. 3 is a cross-sectional view of a copper foil on which a first insulating base material layer is wound by a second reel, with the copper foil positioned on the outer surface of the second reel with respect to the first insulating base material layer.

FIG. 4 is a cross-sectional view after a first insulating base material layer is formed on one surface of the copper foil.

FIG. 5 is a cross-sectional view of forming a conductive wiring layer from the copper foil.

6 is a cross-sectional view of forming a layer of a liquid photosensitive resin material on the other surface of the copper foil and forming the liquid photosensitive resin material into a second insulating base material layer.

FIG. 7 is a first opening formed in a first insulating substrate layer to expose the first surface of the conductive circuit layer, and a plurality of second openings is formed in the second insulating substrate layer to expose the conductive circuit layer. A cross-sectional view of the second surface.

8 is a cross-sectional view of a singulated and separated flexible circuit board.

FIG. 9 is a cross-sectional view of a finally formed flexible circuit board.

In the following, the flexible circuit board and the manufacturing method thereof provided by the present invention will be further described in detail with reference to the accompanying drawings and embodiments. The flexible circuit board of the present invention can be applied to a flexible circuit board or a rigid-flex board.

Please refer to FIGS. 1-9, which is a method for manufacturing a flexible circuit board 100 according to a first embodiment of the present invention, which adopts a roll-to-roll process, which includes steps:

The first step, referring to FIG. 1, is to provide a copper foil 10 wound on a first roll 11. The copper foil 11 may be a rolled copper foil or an electrolytic copper foil, and its thickness is generally 5-50 μm. The copper foil 10 is rolled out from the first reel 11. The copper foil 10 has a first surface 12 and a second surface 14 opposite to the first surface 12.

The second step, please refer to FIG. 2. A layer of liquid photosensitive resin material is formed on the first surface 12 of the copper foil 10 by screen printing, dip coating, spray coating, etc., and the liquid photosensitive resin material is pre-baked to be cured The liquid photosensitive resin material is formed into a first insulating base material layer 121.

The third step, referring to FIG. 3 and FIG. 4, is to provide a second reel 21, and use the second reel 21 to wind the end of the copper foil 10 on which the first insulating substrate layer 121 is formed, so that The copper foil 10 is located on the outer surface of the second roll 21 with respect to the first insulating substrate layer 121.

In a fourth step, referring to FIG. 5, the copper foil 10 is fabricated to form a conductive circuit layer 110. The conductive circuit layer 110 includes a conductive pattern 120 and a gap 130 formed between the conductive patterns 120. In this embodiment, the copper foil 10 is formed into the conductive circuit layer 110 by a dry film exposure etching method.

The specific steps are: setting the dry film on the second surface 14 of the copper foil 10 in a press-fit manner, secondly, exposing and developing the dry film, and then using chemical etching to form the copper foil 10 into a patterned conductive circuit, and then using rinsing Or, the remaining dry film is removed, so that the conductive circuit layer 110 is exposed.

Fifth step, referring to FIG. 6, a layer of liquid photosensitive resin material is formed on the second surface 14, and the liquid photosensitive resin material is formed into a second insulating substrate layer 141, and the second insulating substrate layer 141 covers the conductive pattern 120 and The gap 130 is filled.

Sixth step, referring to FIG. 7, a first opening 123 is formed in the first insulating substrate layer 121 to expose the first surface 12 of the conductive circuit layer 110, and a plurality of second insulating substrate layers 141 are formed. The second opening 143 exposes the second surface 14 of the conductive circuit layer 110, and the first opening 123 is aligned with the position of the second opening 143. In this embodiment, the first opening 123 and the second opening 143 are respectively formed by exposing and developing the first insulating base material layer 121 and the second insulating base material layer 141.

The seventh step, referring to FIG. 8 and FIG. 9, separate the conductive patterns 120 covered by the first insulating base material layer 121 and the second insulating base material layer 141 to obtain a plurality of sheet-like softness. Circuit board 100. Each flexible circuit board 100 includes a conductive circuit layer 110 and a first insulating base material layer 121 and a second insulating base material layer 141 located on opposite surfaces of the conductive circuit layer.

Referring to FIG. 9 again, the second embodiment of the present invention further provides a flexible circuit board 100, which includes a conductive circuit layer 110, a first insulating substrate layer 121 located on two surfaces opposite to the conductive circuit layer 110, and the second An insulating substrate layer 141. The first insulating substrate layer 121 and the second insulating substrate layer 141 are formed by coating a liquid photosensitive resin material on two opposite surfaces of the conductive circuit layer 110 and curing the photosensitive resin material. The flexible circuit board 100 further includes a first opening 123 and a second opening 143. The first opening 123 exposes the first surface 12 of the conductive circuit layer 110, and the second opening 143 exposes the second surface 14 of the conductive circuit layer 110. The position of the first opening 123 is aligned with the position of the second opening 143.

In summary, the hollow-type flexible circuit board provided by the present invention and a manufacturing method thereof, by using a continuous operation mode of a reel-to-reel method, produce a plurality of hollow-type flexible circuit boards, which saves the time and production of the hollow printed circuit board. Manpower improves production efficiency. Secondly, the surface of the conductive circuit layer is covered with a first insulating substrate layer and a second insulating substrate layer made of a photosensitive resin material, that is, there is no adhesive layer on the surface of the conductive circuit layer. Not only the thickness of the circuit board is reduced, but also the impedance of transmitting optical signals can be reduced; the first opening and the second opening are made by exposing and developing the first insulating substrate layer and the second insulating substrate layer, which improves the The alignment accuracy of the first opening and the second opening improves the quality of the hollow circuit board.

In summary, the present invention has indeed met the requirements for an invention patent, and a patent application was filed in accordance with the law. However, the above are only preferred embodiments of the present invention, and the scope of patent application in this case cannot be limited by this. For example, those who are familiar with the skills of this case and equivalent modifications or changes made in accordance with the spirit of the present invention should be covered by the following patent applications.

100‧‧‧ flexible circuit board

10‧‧‧ Copper foil

12‧‧‧first surface

14‧‧‧ second surface

121‧‧‧ the first insulating substrate layer

141‧‧‧Second insulating substrate layer

110‧‧‧ conductive circuit layer

120‧‧‧ conductive pattern

130‧‧‧ Clearance

123‧‧‧First opening

143‧‧‧Second opening

no

Claims (10)

A method for manufacturing a flexible circuit board includes the following steps: Providing a copper foil wound on a first reel, rolling out the copper foil from the first reel, the copper foil having a first surface and a second surface opposite to the first surface; Coating a layer of a liquid photosensitive resin material on the first surface to form the first insulating base material layer of the liquid photosensitive resin material; Fabricating the copper foil to form a conductive circuit layer, the conductive circuit layer including a plurality of conductive patterns and a gap formed between the conductive patterns; A layer of liquid photosensitive resin material is coated on the second surface, and the liquid photosensitive resin material forms a second insulating base material layer. The second insulating base material layer covers the conductive patterns and fills the gaps with the first insulating base. Material layers collectively cover the conductive patterns; and The conductive patterns covered by the first insulating base material layer and the second insulating base material layer are separated and separated to obtain a plurality of flexible circuit boards. Each flexible circuit board includes a conductive circuit layer and a conductive circuit layer. A first insulating base material layer and a second insulating base material layer on opposite surfaces. The method for manufacturing a flexible circuit board according to claim 1, wherein before the forming of the copper foil to form the conductive circuit layer, the method further comprises winding the copper foil on which the first insulating base material layer is formed by a second roll, so that The step of positioning the copper foil on the outer surface of the second roller with respect to the first insulating substrate layer. The method for manufacturing a flexible circuit board according to claim 1, wherein after applying the liquid photosensitive resin material, the method further includes pre-baking the liquid photosensitive resin material to cure the liquid photosensitive resin material to form the first insulating substrate. Layer and the second insulating substrate layer. The method for manufacturing a flexible circuit board according to claim 2, wherein the conductive circuit layer is formed by a dry film exposure etching method or a wet film exposure etching method. The method for manufacturing a flexible circuit board according to claim 4, wherein before obtaining the plurality of flexible circuit boards, the method further includes forming a first opening in the first insulating substrate layer to expose the first surface of the conductive circuit layer, and A plurality of second openings are formed in the second insulating base material layer to expose the second surface of the conductive circuit layer, and the positions of the first openings are aligned with the positions of the second openings. The method for manufacturing a flexible circuit board according to claim 5, wherein the first opening and the second opening are formed by exposing and developing the first insulating base material layer and the second insulating base material layer, respectively. A flexible circuit board includes a conductive circuit layer, a first insulating base material layer and a second insulating base material layer located on opposite surfaces of the conductive circuit layer, the first insulating base material layer and the second insulating base material. The layer is formed by coating a liquid photosensitive resin material on two opposite surfaces of the conductive circuit layer and curing the liquid photosensitive resin material, respectively. The flexible circuit board according to claim 7, wherein the conductive circuit layer includes a plurality of conductive patterns and gaps formed between the conductive patterns, the second insulating base material layer further fills the gaps, and the second insulating base The material layer and the first insulating substrate layer jointly cover the conductive patterns. The flexible circuit board according to claim 8, further comprising a first opening and a second opening, the first opening exposing a first surface of the conductive circuit layer, and the second opening exposing a second surface of the conductive circuit layer The position of the first opening is aligned with the position of the second opening. The flexible circuit board according to claim 9, wherein the first opening and the second opening are formed by exposing and developing the first insulating base material layer and the second insulating base material layer, respectively.