CN114340194A - Circuit board preparation method - Google Patents
Circuit board preparation method Download PDFInfo
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- CN114340194A CN114340194A CN202111679701.9A CN202111679701A CN114340194A CN 114340194 A CN114340194 A CN 114340194A CN 202111679701 A CN202111679701 A CN 202111679701A CN 114340194 A CN114340194 A CN 114340194A
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- circuit board
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- protection layer
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Abstract
The invention relates to a circuit board preparation method, which comprises the following circuit preparation steps: s1, manufacturing a metal protection layer on the copper foil layer on the surface of the circuit board, wherein the metal protection layer at least comprises a silver protection layer; s2, attaching an acid-resistant film on the metal protection layer, and then exposing and developing to expose the region to be etched of the metal protection layer from the film; s3, carrying out electrolytic etching on the metal protective layer in an acidic or neutral electrolyte to remove the area to be etched of the metal protective layer; s4, performing acid etching on the copper foil layer to remove the area of the copper foil layer exposed to the film and form a conductive circuit; and S5, removing the film. The preparation method can effectively solve the problems that the silver protective layer is easy to stain and yellow due to vulcanization in the prior art, improve the processing quality and yield of the circuit board, and can realize the manufacture of fine lines.
Description
Technical Field
The invention relates to a circuit board preparation method.
Background
In the circuit board manufacturing process, it is necessary in many cases to fabricate a metal resist such as an oxidation resistant layer on the surface of its outer wiring (e.g., the surface of a land exposed to a solder resist layer), the metal resist usually including a silver resist, typically a combination of a nickel resist and a silver resist. The nickel-silver alloy can ensure that the silver surface is smooth and bright, has high light reflectivity, and has very obvious advantages on products with strict requirements on high brightness and welding flatness.
Chinese patent document CN113825321A discloses a circuit board manufacturing method, which includes the following circuit manufacturing steps: forming a seed layer and a copper film layer on a carrier of the circuit board in sequence; manufacturing a circuit pattern on the circuit board; filling blue gel in the non-circuit area of the circuit pattern; forming an anti-oxidation layer on the surface of the circuit region of the circuit pattern, wherein the anti-oxidation layer is one or more of nickel, tin, gold and silver; and removing the filled blue gel to obtain the oxidation-resistant circuit board.
In the prior art such as disclosed in the above patent documents, a copper line is usually etched to form an outer layer, and then a blue glue is used to cover the surface of a circuit board on which a metal protection layer is not required to be formed, and then a metal protection layer including a silver protection layer is electroplated on the copper line. However, because the bonding force between the blue gel and the circuit board is low, a gap is easily generated between the edge of the blue gel and the circuit board in the production process, and electroplating solution is remained, so that the problem that the surface of the silver protective layer is often stained or yellow in vulcanization is caused.
Disclosure of Invention
The invention mainly aims to provide a circuit board preparation method to solve the problems that a silver protective layer on the surface of a circuit is easy to stain and become yellow due to vulcanization in the prior art.
In order to achieve the above main object, the present invention provides a method for manufacturing a circuit board, which comprises the following steps:
s1, manufacturing a metal protection layer on the copper foil layer on the surface of the circuit board, wherein the metal protection layer at least comprises a silver protection layer;
s2, attaching an acid-resistant film on the metal protection layer, and then exposing and developing to expose the region to be etched of the metal protection layer from the film;
s3, performing electrolytic etching on the metal protection layer in an acidic or neutral electrolyte to remove the region to be etched of the metal protection layer;
s4, performing acid etching on the copper foil layer, and removing the area of the copper foil layer exposed to the film to form a conductive circuit;
and S5, removing the film.
According to a specific embodiment of the present invention, the metal protection layer further includes a nickel protection layer formed on a surface of the copper foil layer, and the silver protection layer is formed on the nickel protection layer.
Further, the thickness of the nickel protective layer is 1-10 μm.
Further, the thickness of the silver protective layer is 1 μm to 10 μm.
Further, the electrolytic etching of the silver protective layer and the nickel protective layer is performed under the same electrolytic system.
Preferably, in the step S3, the pH of the electrolyte is controlled to be 5 to 7.
Preferably, the temperature of the electrolyte is controlled to be 25 ° to 35 ° in step S3.
Preferably, a stainless steel plate is used as the cathode plate in step S3.
Preferably, the metal protection layer is manufactured by an electroplating process in step S1.
Preferably, the circuit board is water-washed after step S3 and before step S4.
The circuit board preparation method has the following beneficial effects:
the silver protective layer is protected by the acid-resistant film during electrolytic etching, and the film and the silver protective layer have good binding force, so that the phenomenon that electrolyte and etching solution remain on the circuit board is avoided, the problems that the silver protective layer is easy to stain and is vulcanized and yellowed in the prior art can be well solved, and the yield and the quality of products are improved.
And the film has higher graphic precision than blue glue after exposure and development, which is beneficial to improving the graphic precision of the circuit and realizing the manufacture of fine circuits.
To more clearly illustrate the objects, technical solutions and advantages of the present invention, the present invention will be further described in detail with reference to the accompanying drawings and detailed description.
Drawings
FIG. 1 is a flow chart of an embodiment of a method of making a circuit board according to the present invention;
FIG. 2 is a schematic diagram of the structure of the circuit board after exposure and development of the film in the embodiment;
FIG. 3 is a schematic diagram of the circuit board structure after the metal protection layer is electrolytically etched according to an embodiment;
FIG. 4 is a schematic diagram of the circuit board structure after the copper foil layer is acid etched in the embodiment.
It should be noted that, in order to clearly illustrate the structures that are being represented, the various parts of the drawings may not be drawn to the same scale. Therefore, unless otherwise indicated, the drawings are not intended to limit the dimensions and proportional relationships of the circuit board components.
Detailed Description
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited to the specific embodiments disclosed below.
As shown in fig. 1, the circuit board manufacturing method according to the embodiment of the present invention includes the following circuit manufacturing steps:
s1, manufacturing a metal protection layer on the copper foil layer on the surface of the circuit board;
s2, attaching an acid-resistant film on the metal protection layer, and then exposing and developing to expose the region to be etched of the metal protection layer from the film;
s3, carrying out electrolytic etching on the metal protective layer in an acidic or neutral electrolyte to remove the area to be etched of the metal protective layer;
s4, performing acid etching on the copper foil layer, and removing the area of the copper foil layer exposed to the film to form a conductive circuit;
and S5, removing the film.
In an alternative embodiment, as shown in fig. 2, the circuit board includes a copper foil layer 11 formed on a surface of an insulating substrate (e.g., an FR-4 substrate), and the metal cap layer includes a nickel cap layer 12 formed on the copper foil layer 11 and a silver cap layer 13 formed on the nickel cap layer 12. Wherein, the thickness of the nickel protective layer 12 may be 1 μm to 10 μm, preferably 3 μm to 10 μm, but the invention is not limited thereto; the thickness of the silver protective layer 13 may be 1 μm to 10 μm, and preferably 3 μm to 10 μm, but the present invention is not limited thereto.
In the embodiment of the present invention, the circuit board may be sequentially subjected to the entire-board nickel electroplating and silver electroplating, thereby forming the nickel protective layer 12 on the copper foil layer 11 and the silver protective layer 13 on the nickel protective layer 12. It should be noted that. In other embodiments of the present invention, the metal protective layer may include only the silver protective layer 13 directly formed on the copper foil layer 11.
Before the metal protection layer is electrolytically etched, as shown in fig. 2, first, an acid-resistant film 14 is attached to the silver protection layer 13, and then, the film 14 is exposed and developed, so that the film 14 forms a pattern matching the outer layer circuit, and the region to be etched of the metal protection layer is exposed from the patterned film 14. Preferably, the circuit board is washed and dried before the film 14 is attached.
In the embodiment of the present invention, the nickel protective layer 12 and the silver protective layer 13 are subjected to partial electrolytic etching in an acidic or neutral electrolyte to remove the regions to be etched, where the nickel protective layer 12 and the silver protective layer 13 are exposed to the film 14 (see fig. 3). Specifically, during electrolytic etching, a circuit board as an anode plate is electrically connected to a positive electrode of a direct current power supply, a stainless steel plate as a cathode plate is electrically connected to a negative electrode of the direct current power supply, and the circuit board and the stainless steel plate are both placed in an acidic or neutral electrolyte and are opposed to each other at a distance of about 20 cm. Preferably, the pH value of the electrolyte is controlled to be 5-7 during electrolytic etching, and the temperature of the electrolyte is controlled to be 25-35 degrees, so that a better electrolytic etching effect is realized. The electrolyte used in the present invention may be the same as the prior art and will not be described herein.
In the embodiment of the present invention, the electrolytic etching of the silver protective layer 13 and the nickel protective layer 12 is performed in the same electrolytic system, which is advantageous for improving the production efficiency. In other alternative embodiments of the present invention, the silver protective layer 13 and the nickel protective layer 12 may be electrolytically etched separately under different electrolytic systems.
Preferably, after the electrolytic etching, the circuit board is washed with water. Then, as shown in fig. 4, the copper foil layer 11 is placed in an acidic etching solution to perform chemical etching to remove the area of the copper foil layer 11 exposed to the film 14 to be etched, thereby forming a conductive line. The etching of the copper foil layer 11 may be the same as in the prior art and will not be described in detail.
And finally, removing the film from the surface of the circuit board, and then washing and drying the circuit board to finish the circuit manufacturing step.
In summary, in the embodiment of the invention, when the surface circuit of the circuit board is manufactured, the metal protection layer is manufactured on the whole surface of the copper foil layer of the circuit board, the region to be etched of the metal protection layer is removed by electrolytic etching, and the silver protection layer is protected by the acid-resistant film during electrolytic etching.
Although the present invention has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention.
Claims (10)
1. A circuit board preparation method is characterized by comprising the following circuit manufacturing steps:
s1, manufacturing a metal protection layer on the copper foil layer on the surface of the circuit board, wherein the metal protection layer at least comprises a silver protection layer;
s2, attaching an acid-resistant film on the metal protection layer, and then exposing and developing to expose the region to be etched of the metal protection layer from the film;
s3, performing electrolytic etching on the metal protection layer in an acidic or neutral electrolyte to remove the region to be etched of the metal protection layer;
s4, performing acid etching on the copper foil layer, and removing the area of the copper foil layer exposed to the film to form a conductive circuit;
and S5, removing the film.
2. The method for manufacturing a circuit board according to claim 1, wherein: the metal protection layer further comprises a nickel protection layer formed on the surface of the copper foil layer, and the silver protection layer is formed on the nickel protection layer.
3. The method for manufacturing a circuit board according to claim 2, wherein: the thickness of the nickel protective layer is 1-10 μm.
4. The method for manufacturing a circuit board according to claim 2, wherein: the thickness of the silver protective layer is 1-10 mu m.
5. The method for manufacturing a circuit board according to claim 2, wherein: the electrolytic etching of the silver protective layer and the nickel protective layer is performed under the same electrolytic system.
6. The method for manufacturing a circuit board according to claim 1, wherein: and step S3, controlling the pH value of the electrolyte to be 5-7.
7. The method for manufacturing a circuit board according to claim 1, wherein: in step S3, the temperature of the electrolyte is controlled to be 25 ° to 35 °.
8. The method for manufacturing a circuit board according to claim 1, wherein: in step S3, a stainless steel plate is used as a cathode plate.
9. The method for manufacturing a circuit board according to claim 1, wherein: in step S1, the metal protection layer is formed by an electroplating process.
10. The method for manufacturing a circuit board according to claim 1, wherein: after step S3 and before step S4, the circuit board is water-washed.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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CN202111679701.9A CN114340194A (en) | 2021-12-31 | 2021-12-31 | Circuit board preparation method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202111679701.9A CN114340194A (en) | 2021-12-31 | 2021-12-31 | Circuit board preparation method |
Publications (1)
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CN114340194A true CN114340194A (en) | 2022-04-12 |
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Family Applications (1)
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CN202111679701.9A Pending CN114340194A (en) | 2021-12-31 | 2021-12-31 | Circuit board preparation method |
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CN (1) | CN114340194A (en) |
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2021
- 2021-12-31 CN CN202111679701.9A patent/CN114340194A/en active Pending
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