TW201811136A - Printed circuit board with thick copper conducting line and method same - Google Patents

Abstract

The present invention relates to a method for manufacturing a printed circuit board with thick copper conducting line, include steps as follows: providing a copper clad substrate comprising an insulating layer and a first copper layer formed on the insulating layer; forming a photosensitive film on the first copper layer; forming a plurality of openings in the photosensitive film, and the openings exposes part of the first copper layer; etching the first copper layer from the openings for a first time, and obtain a first conducting line pattern, the first conducting line pattern includes a plurality of trapezoids connecting with each other and a plurality of first opening portions formed between each two adjacent trapezoids, the first opening portion includes two side walls and a bottom wall between the two side walls; forming a protecting layer on the side walls; etching the first copper layer form the bottom wall for a second time and form a second conducting line pattern; and removing the photosensitive film, and the first conducting line pattern and the second conducting line pattern together form a conducting line structure, and the printed circuit board with thick copper conducting line is obtained.

Description

Circuit board with thick copper circuit and manufacturing method thereof

The invention relates to the field of circuit board manufacturing, in particular to a circuit board with thick copper lines and a manufacturing method thereof.

With the rapid development of electronic products, printed circuit boards used as component supports and carriers for transmitting electrical signals should also gradually move towards miniaturization, light weight, high density, and multi-function, and then to fine copper circuits on printed circuit boards. The production made higher requirements. The width of the conventional printed circuit board production process is limited by the thickness of the copper layer. The thinner the copper layer, the thicker the copper, so using thick copper to make thick copper circuits has its own limitations; and the conductive lines of conventional printed circuit boards are usually For the subtractive method, but limited by the thickness of copper, the production of thick copper lines can only be matched with thin copper, and there is a poor etching factor after fabrication, and the etching does not form burrs; the solder resist ink is difficult to fill, and it is easy to generate bubbles.

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

A method for manufacturing a circuit board with thick copper lines includes the following steps:

Provide a copper-clad substrate, which includes an insulating layer and a first copper foil layer formed on one surface of the insulating layer;

Forming a photosensitive film on the surface of the first copper foil layer;

Forming a plurality of openings in the photosensitive film, the openings exposing the first copper foil layer;

The first copper foil layer is etched for the first time from the position of the opening to obtain a first conductive circuit pattern. The first conductive circuit pattern includes a plurality of connected trapezoids and first openings formed between adjacent trapezoids. The first opening includes two side walls and a bottom wall connecting the two side walls;

Forming a protective layer on the surface of the side wall;

Performing a second etching on the first copper foil layer from the position of the bottom wall to form a second conductive circuit pattern; and

The dry film is removed, and the first conductive circuit pattern and the second conductive circuit pattern together form a conductive circuit layer, thereby obtaining a circuit board with a thick copper circuit.

A circuit board with a thick copper circuit includes an insulating layer and a conductive circuit layer formed on a surface of the insulating layer. The conductive circuit layer includes a second conductive circuit pattern formed on the surface of the insulating layer and a phase corresponding to the second conductive line pattern. A stacked first conductive circuit pattern including a plurality of connected trapezoids and a first opening formed between adjacent trapezoids, the first opening including two side walls and a bottom connecting the two side walls A wall, the side wall is formed with a protective layer, the first conductive line pattern is formed with a plurality of first openings, and the second conductive line pattern is formed with a plurality of second openings respectively communicating with the first opening, The second opening portion exposes the insulating layer.

A circuit board with a thick copper circuit includes an insulating layer and two conductive circuit layers formed on two surfaces opposite to each other, each of the conductive circuit layers including a second conductive circuit pattern formed on a surface of the insulating layer. And a first conductive line pattern stacked with a second conductive line pattern, the first conductive line pattern includes a plurality of connected trapezoids and a first opening formed between adjacent trapezoids, the first opening includes two A side wall and a bottom wall connecting the two side walls, the side wall is formed with a protective layer, the first conductive circuit pattern is formed with a plurality of first openings, and the second conductive circuit pattern is formed with a plurality of first openings respectively. A second opening portion that communicates with each other, the second opening portion exposing the insulating layer.

Compared with the prior art, the present invention provides a method for manufacturing a circuit board with a thick copper circuit and a circuit board made therefrom. The first copper foil layer on one surface of the insulation layer is etched twice to form the conductive layer. The circuit layer, in this way, can reduce the risk of etching of the sidewall of the circuit, effectively reduce the phenomenon of burr of the circuit, and can obtain thicker copper circuits. After testing, the line width is about 50 μm. The metal tin formed on the sidewall of the first conductive circuit pattern It can protect the conductive circuit layer and make the conductive circuit layer more resistant to oxidation.

FIG. 1 is a cross-sectional view of a copper-clad substrate provided by a first embodiment of the present invention.

2 is a cross-sectional view of a photosensitive film formed on a surface of a copper-clad substrate.

FIG. 3 is a cross-sectional view of an opening formed by exposure and development of a photosensitive film.

4 is a cross-sectional view of a first copper foil layer etched for the first time to form a first conductive circuit pattern.

5 is a cross-sectional view of a protective layer formed on a surface of a first conductive circuit pattern.

6 is a cross-sectional view of a protective layer with a bottom wall of the first conductive circuit pattern removed.

FIG. 7 is a cross-sectional view of performing a second etching on the first copper foil layer to form a second conductive circuit pattern.

FIG. 8 is a cross-sectional view with the etch stop layer removed.

FIG. 9 is a cross-sectional view in which pure glue is filled between the surface of the insulating layer and the conductive circuit layer.

FIG. 10 is a cross-sectional view of a circuit board with a thick copper circuit laminated on the surface of the conductive circuit layer.

FIG. 11 is a cross-sectional view of another circuit board with a thick copper circuit provided by a third embodiment of the present invention.

The circuit board and the manufacturing method thereof provided by the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

Please refer to FIGS. 1-10. A first embodiment of the present invention provides a method for manufacturing a circuit board with thick copper lines. The steps include:

In the first step, referring to FIG. 1, a copper-clad substrate 10 is provided. The copper-clad substrate 10 is a single-sided copper-clad substrate. The copper-clad substrate includes an insulating layer 12 and a first copper foil layer 14 formed on a surface of the insulating layer 12. The thickness of the first copper foil layer 14 is 70 μm, and the thickness of the insulating layer 12 is approximately 25 μm.

Step 2: Referring to FIG. 2 and FIG. 3, a photosensitive film 16 is formed on the surface of the first copper foil layer 14 and a plurality of openings 160 are formed in the photosensitive film 16, and the openings 160 expose the first copper. Foil layer 14. In this embodiment, the photosensitive film 16 is a dry film, and the plurality of openings 160 are formed by a lithography process. The thickness of this photosensitive film 16 is 15 μm. The photosensitive film 16 after exposure and development forms an etch stop layer 162, and the first copper foil layer 14 covered by the etch stop layer 162 is not etched.

In the third step, referring to FIG. 4, the first copper foil layer 14 is etched for the first time from the position of the opening 160 to obtain a first conductive circuit pattern 20. The first conductive circuit pattern 20 includes a plurality of connected trapezoids. 201 and a first opening 202 formed between adjacent trapezoids 201. The first opening 202 includes a side wall 22 and a bottom wall 24 connecting the adjacent side walls 22. The depth of the first etching of the first copper foil layer 14 from the position of the opening 160 is about half of the thickness of the first copper foil layer 14. In this embodiment, the depth of the first etching is 35 μm. Because the etching factor occurs when the first copper foil layer 14 is etched, the cross sections of the plurality of first openings 202 formed are substantially inverted trapezoids spaced apart from each other.

In the fourth step, referring to FIG. 5, a protective layer 240 is formed on the surfaces of the bottom wall 24 and the side wall 22. The protective layer 240 is formed by metal plating. The plated metal is tin or nickel. The thickness of the plated metal is about 1-3um. In other embodiments, the protective layer 240 may be formed on the surface of the first conductive circuit pattern 20 by tinning (sinking). The first conductive circuit pattern 20 covered by the protective layer 240 is not etched. The protective layer 240 is used to protect the first circuit pattern 20 from being oxidized.

In a fifth step, referring to FIG. 6, the protective layer 240 formed on the bottom wall 24 is removed, so that the first opening portion 202 exposes a part of the first copper foil layer 14. In this embodiment, the protective layer 240 of the bottom wall 24 can be removed by a laser ablating method.

The sixth step, please refer to FIG. 7, the second copper foil layer 14 is etched from the position of the bottom wall 24 a second time, and the first copper foil layer 14 remaining after the first etching is made to form a second conductive layer. A circuit pattern 30. The second conductive circuit pattern 30 includes a plurality of trapezoids 301 connected in sequence and second openings 302 formed between adjacent trapezoids. Each of the second opening portions 302 is in communication with one of the first opening portions 202, and the second opening portion 302 exposes the insulating layer 12. The plurality of second openings 302 have a substantially inverted trapezoidal shape in cross section. The first conductive circuit pattern 20 and the second circuit pattern 30 together form a conductive circuit layer 60 on the surface of the insulating layer 12. The line width of the conductive circuit layer 60 can reach 50 μm.

In a seventh step, referring to FIG. 8, the etching stop layer 162 on the surface of the first conductive circuit pattern 20 is peeled off.

Eighth step, please refer to FIG. 9 and FIG. 10. On the surface of the insulating layer 12, the first opening portion 202 and the second opening portion 302 included in the conductive circuit layer 60 are filled with pure glue 40. The pure glue 40 fills the first glue portion 40. An opening 202, a second opening 302, and the first conductive circuit pattern 20 are covered, and a cover film 50 (CoverLay) is laminated on the surface of the pure glue 40, so as to obtain a circuit board 200 having a thick copper circuit.

Since a thick copper thick copper circuit is formed in this case, the conductive circuit layer 60 formed by the first conductive circuit pattern 20 and the second conductive pattern 30 includes a first opening portion 202 and a second opening portion 302 (Pitch) which are narrower, and It is difficult to fill the first opening portion 202 and the second opening portion 302 with the molten colloid included in the cover film 50 only by laminating the cover film 50 on the surface of the conductive circuit layer 60. Therefore, in this embodiment, the conductive layer The first opening 202 and the second opening 302 of the circuit layer 60 are filled with pure glue 40, and then a cover film 50 is laminated on the surface of the conductive circuit layer 60. The pure glue 40 and the cover film 50 are used for The conductive circuit layer 60 is protected.

Please refer to FIG. 10 again. The second embodiment of the present invention further provides a circuit board 200 manufactured by the method for manufacturing a circuit board with thick copper lines, which includes an insulating layer 12 and a conductive circuit layer 60 formed on a surface of the insulating layer 12. The conductive circuit layer 60 includes a second conductive circuit pattern 20 formed on a surface of the insulating layer 12 and a first conductive circuit pattern 30 stacked on the second conductive line pattern 20.

The first conductive circuit pattern 20 includes a plurality of connected trapezoids 201 and a first opening 202 formed between adjacent trapezoids 201. The first opening 202 includes two side walls 22 and a bottom wall connecting the two side walls 22. 24. A protective layer 240 is formed on the sidewall 22. The protective layer 240 is a metal protective layer.

The shape of the second conductive circuit pattern 30 is substantially the same as that of the first conductive circuit pattern 20. The second conductive circuit pattern 30 includes a plurality of connected trapezoids 301 and second openings 302 formed between adjacent trapezoids 301. Each second opening 302 The second openings 302 are in communication with one of the first openings 202 and are substantially equal in size to the first openings 202. The second openings 302 expose the insulating layer 12. The cross sections of the first opening 202 and the second opening 302 are approximately inverted trapezoids.

The first opening portion 202 and the second opening portion 302 are filled with pure glue 40. The pure glue 40 also covers the surface of the first conductive circuit pattern 20. A cover film 50 is formed on the pure glue 40 surface.

Please refer to FIG. 11, a third embodiment of the present invention further provides a circuit board 300 manufactured by the method for manufacturing a circuit board with thick copper lines, which includes an insulating layer and two formed on two opposite surfaces of the insulating layer 12. Each of the conductive circuit layers 60 includes a second conductive circuit pattern 30 formed on a surface of the insulating layer 12 and a first conductive circuit pattern 20 stacked on the second conductive line pattern 30.

The first conductive circuit pattern 20 includes a plurality of connected trapezoids and a first opening portion 202 formed between adjacent trapezoids. The first opening portion 202 includes two side walls 22 and a bottom wall 24 connecting the two side walls 22. A protective layer 240 is formed on the sidewall 22. The protective layer 240 is a metal protective layer.

The second conductive circuit pattern 30 includes a plurality of connected trapezoids and second opening portions 302 formed between adjacent trapezoids, and each of the second opening portions 302 communicates with one of the first opening portions 202, respectively.

The first opening portion 202 and the second opening portion 302 are filled with pure glue 40. The pure glue 40 also covers the surface of the first conductive circuit pattern 20. A cover film 50 is formed on the pure glue 40 surface.

In summary, the present invention provides a method for manufacturing a circuit board with thick copper lines and a circuit board manufactured therefrom. The first copper foil layer 14 on one surface of the insulating layer is etched twice to form the conductive layer. In this way, the wiring layer 60 can reduce the risk of etching the sidewalls of the wiring, effectively reduce the phenomenon of burrs on the wiring, and obtain a finer wiring. After testing, the wiring width is about 50 μm. The wiring formed on the sidewall of the first conductive wiring pattern 20 The protective layer 240 can protect the conductive circuit layer 60 and make the conductive circuit layer 60 more resistant to oxidation.

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.

200,300

Circuit board with thick copper wiring:

10‧‧‧ Copper-clad substrate

14‧‧‧The first copper foil layer

12‧‧‧ Insulation

16‧‧‧ photosensitive film

160‧‧‧ opening

162‧‧‧Etching barrier

20‧‧‧ the first conductive circuit pattern

24‧‧‧ bottom wall

22‧‧‧ sidewall

240‧‧‧ protective layer

30‧‧‧ the second conductive line pattern

40‧‧‧Pure rubber

50‧‧‧ cover film

60‧‧‧Conductive circuit layer

201, 301‧‧‧ trapezoid

202‧‧‧First opening

302‧‧‧Second opening

no

200‧‧‧ Circuit board with thick copper wiring

12‧‧‧ Insulation

20‧‧‧ the first conductive circuit pattern

30‧‧‧ the second conductive line pattern

40‧‧‧Pure rubber

50‧‧‧ cover film

60‧‧‧Conductive circuit layer

201, 301‧‧‧ trapezoid

202‧‧‧First opening

302‧‧‧Second opening

Claims (12)

A method for manufacturing a circuit board with thick copper lines includes the following steps:
Provide a copper-clad substrate, which includes an insulating layer and a first copper foil layer formed on one surface of the insulating layer;
Forming a photosensitive film on the surface of the first copper foil layer;
Forming a plurality of openings in the photosensitive film, the openings exposing the first copper foil layer;
The first copper foil layer is etched for the first time from the position of the opening to obtain a first conductive circuit pattern. The first conductive circuit pattern includes a plurality of connected trapezoids and first openings formed between adjacent trapezoids. The first opening includes two side walls and a bottom wall connecting the two side walls;
Forming a protective layer on the surface of the side wall;
Etch the first copper foil layer for a second time from the position of the bottom wall to form a second conductive circuit pattern; and remove the photosensitive film, the first conductive circuit pattern and the second conductive circuit pattern together form electrical conductivity Circuit layer to obtain a circuit board with thick copper wiring. The method for manufacturing a circuit board with a thick copper circuit according to claim 1, wherein the step of forming the protective layer on the sidewall is:
Plating a metal layer on the bottom wall and the sidewall respectively;
The laser ablation method is used to remove the metal layer on the bottom wall and only the metal layer on the side wall is retained, and the remaining metal layer forms the protective layer. The method for manufacturing a circuit board with a thick copper circuit according to claim 2, wherein the metal layer to be plated is tin or nickel. The method for manufacturing a circuit board with a thick copper circuit according to claim 1, wherein a depth of performing the first etching on the first copper foil layer is equal to a depth of performing the second etching on the first copper foil layer. . The method for manufacturing a circuit board with a thick copper circuit according to claim 4, wherein the second conductive circuit pattern includes a plurality of connected trapezoids and second openings formed between adjacent trapezoids, each second The openings communicate with one of the first openings, respectively. The method for manufacturing a circuit board with a thick copper circuit according to claim 5, wherein removing the photosensitive film further includes filling pure rubber in the first opening portion and the second opening portion and filling the pure rubber with The step of laminating a cover film on the surface. A circuit board with a thick copper circuit includes an insulating layer and a conductive circuit layer formed on a surface of the insulating layer. The conductive circuit layer includes a second conductive line pattern formed on the surface of the insulating layer and the second conductive line pattern. A stacked first conductive circuit pattern, the first conductive circuit pattern includes a plurality of connected trapezoids and first openings formed between adjacent trapezoids, each of the first openings includes two side walls and connects two A bottom wall of the side wall, the side wall is formed with a protective layer, and the second conductive circuit pattern includes a plurality of second opening portions respectively communicating with the first opening portion, and the second opening portion exposes the insulating layer. The circuit board with thick copper wiring according to claim 7, wherein the second conductive circuit pattern further includes a plurality of connected trapezoids, and the second opening portion is formed between every two adjacent trapezoids. The circuit board with a thick copper circuit according to claim 8, wherein the first opening portion and the second opening portion are further filled with pure glue, and a cover film is formed on a surface of the pure glue. A circuit board with thick copper lines includes an insulating layer and two conductive circuit layers formed on two surfaces opposite to the insulating layer. Each of the conductive circuit layers forms a second conductive circuit pattern on the surface of the insulating layer. A first conductive line pattern stacked with the second conductive line pattern, the first conductive line pattern including a plurality of connected trapezoids and first openings formed between adjacent trapezoids, each of the first openings including Two side walls and a bottom wall connecting the two side walls, the side wall is formed with a protective layer, and the second conductive circuit pattern includes a plurality of second openings which are respectively communicated with the first openings, and the second openings The insulation layer is exposed. The circuit board with thick copper lines according to claim 10, wherein the second conductive circuit pattern further includes a plurality of connected trapezoids, and the second opening portion is formed between every two adjacent trapezoids. The circuit board with a thick copper circuit according to claim 11, wherein the first opening portion and the second opening portion are further filled with pure glue, and a cover film is formed on a surface of the pure glue.