TWI531285B - Circuit board and method for manufacturing same - Google Patents

Description

Circuit board and manufacturing method thereof

The invention relates to a circuit board manufacturing technology, in particular to a circuit board and a manufacturing method thereof.

With the development of electronic products in the direction of miniaturization and high speed, circuit boards have also evolved from single-sided circuit boards and double-sided circuit boards to multilayer circuit boards. A multi-layer circuit board refers to a circuit board having a plurality of layers of conductive lines, which has a large wiring area and a high interconnection density, and thus is widely used, see the literature Takahashi, A. Ooki, N. Nagai, A. Akahoshi, H. Mukoh, A. Wajima, M. Res. Lab., High density multilayer printed circuit board for HITAC M-880, IEEE Trans. on Components, Packaging, and Manufacturing Technology, 1992, 15(4): 418-425.

A printed circuit board having a refinement conductive line is generally produced by providing an insulating substrate; forming a conductive layer on the surface of the insulating substrate; forming a photoresist layer on the surface of the conductive layer; and applying the photoresist layer to the photoresist layer Exposure and development are performed; the conductive layer is etched to obtain a conductive line; and the photoresist layer is removed. In the above manufacturing method, it is necessary to use a photoresist and a whole conductive layer, and in the process of exposure, development, etching, etc., a corresponding chemical reagent is required and a large amount of water is required for cleaning. Therefore, the manufacturing method in the prior art has serious pollution to the environment, and the production cost of the circuit board is high.

Therefore, it is necessary to provide a circuit board manufacturing method and a circuit board which can reduce environmental pollution.

A method for manufacturing a circuit board, comprising the steps of: providing a conductive polymer monomer and a soluble metal salt solution; uniformly mixing the conductive polymer monomer and a soluble metal salt solution to obtain a precursor; providing a substrate; and using the precursor The body is coated on the surface of the substrate to form a conductive line pattern; the conductive line pattern is irradiated with ultraviolet light to harden it, and the conductive polymer monomer is polymerized to obtain a conductive polymer, and the metal ion of the metal salt is Reducing to a simple metal material to obtain a conductive wiring film; and forming a plating metal layer on the surface of the conductive wiring film, the plating metal layer and the conductive wiring film forming a conductive path.

According to the circuit board and the manufacturing method thereof, the monomer of the conductive polymer and the precursor including the metal ion are coated on the surface of the substrate, and are irradiated with ultraviolet light to be cured into a conductive line film. The conductive line film comprises a conductive polymer material and a metal element, and has good electrical conductivity, and can form a plated metal layer directly on the surface thereof as a subsequent step. Therefore, the manufacturing method of the circuit board provided by the technical solution does not require exposure, development, and etching when manufacturing the conductive line, thereby avoiding the use of a large amount of chemical reagents and requiring a large amount of water resources. Therefore, the circuit board manufacturing method provided by the technical solution can reduce environmental pollution and reduce the production cost of the circuit board. Further, in the technical solution, the formation of the conductive line film only needs to be irradiated with ultraviolet light, and does not require high-temperature baking treatment, thereby avoiding damage of the insulating layer in the substrate during high-temperature baking.

110‧‧‧Substrate

120‧‧‧ conductive circuit pattern

121‧‧‧ Conductive film

150‧‧‧ plating barrier

151‧‧‧ openings

130‧‧‧Electroplated metal layer

140‧‧‧Electrical circuit

100‧‧‧ boards

1 is a schematic cross-sectional view of a substrate provided by an embodiment of the present technical solution.

2 is a schematic cross-sectional view showing the surface of the substrate of FIG. 1 after forming a conductive line pattern.

3 is a schematic cross-sectional view showing the conductive circuit pattern of FIG. 2 after being irradiated with ultraviolet light to obtain a conductive line film.

4 is a schematic cross-sectional view showing the surface of the substrate of FIG. 3 after forming a plating barrier layer.

FIG. 5 is a schematic cross-sectional view showing the surface of the conductive wiring film of FIG. 4 after forming a plated metal layer.

6 is a schematic cross-sectional view of a circuit board fabricated by the present technical solution.

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

The manufacturing method of the circuit board provided by the embodiment of the technical solution includes the following steps:

In the first step, a conductive polymer monomer and a soluble metal salt solution are provided.

The conductive polymer monomer is a monomer having conductivity in a polymer formed after polymerization. The conductive polymer monomer may specifically be aniline, pyrrole or thiophene, or may be a derivative of aniline, a pyrrole derivative or a thiophene derivative, such as 3,4-ethylenethiophene or 2,5-dimethylene. Oxyaniline and the like. The conductive polymer monomer is usually a liquid.

The soluble metal salt solution may be a soluble copper salt solution, a soluble silver salt solution or a soluble palladium salt solution or the like. In the present embodiment, a copper sulfate solution will be described as an example.

In the second step, the conductive polymer monomer and the soluble metal salt solution are uniformly mixed to obtain a precursor.

In this step, mechanical stirring or other means may be used to make the conductive polymer The monomer and the soluble metal salt solution are uniformly mixed.

In the third step, referring to FIG. 1, a substrate 110 is provided.

The substrate 110 may be an insulating substrate or a circuit substrate on which a conductive line has been formed, and one side of the circuit substrate is an insulating substrate. The material of the insulating substrate may be a material commonly used for making an insulating layer in a circuit board manufacturing process, such as polyimide or the like. In the present embodiment, the substrate 110 is an insulating substrate as an example.

In the fourth step, referring to FIG. 2, the precursor is coated on the surface of the substrate 110 to form a conductive line pattern 120.

In this step, the precursor may be applied to form a conductive line pattern 120 on the surface of the substrate 110 by screen printing, inkjet printing or spin coating. The shape and distribution of the conductive trace pattern 120 are the same as the distribution and shape of the conductive trace to be formed.

In the fifth step, referring to FIG. 3, the conductive line pattern 120 is hardened by ultraviolet light to obtain a conductive line film 121.

By irradiating with ultraviolet light, the conductive polymer monomer in the precursor in the conductive wiring pattern 120 is polymerized to form a conductive polymer, and is closely bonded to the surface of the substrate 110. During the polymerization of the conductive polymer monomer, free electrons may be generated, and metal ions of the soluble metal salt solution in the precursor in the conductive line pattern 120 are combined with the free electrons and reduced to metal. The elemental substance is such that the metal element atoms in the conductive wiring film 121 are connected to each other to further increase the electrical conductivity of the hardened conductive line pattern 120.

Further, in this embodiment, the ultraviolet light is used in the wavelength range of 330 nm to 400 nm. It is preferably 365 nm. When a derivative of aniline, a pyrrole derivative or a thiophene derivative is used as the conductive polymer monomer, if an electron-repellent group such as a methoxy group is attached to the ring structure of the monomer, the monomer can be more favored. The metal ions of the electrons are supplied to the metal salt during the polymerization to facilitate the reduction of the metal ions to the metal element. For example, when the conductive polymer monomer is 2,5-dimethoxyaniline, a methoxy group is bonded to the 2 and 5 positions of the benzene ring, and since the methoxy group has electron-repellency, the monomer is accelerated. The metal ions of the metal salt are supplied during the polymerization to facilitate the reduction of the metal ions to the metal element.

In addition, since the conductive polymer obtained after the polymerization has an oxidation/reduction state conversion property, free electrons can be released during the oxidation/reduction state conversion of the conductive polymer, thereby further accelerating the reduction of the metal ions to Metal element.

The conductive polymer obtained in the conductive wiring film 121 may be polyaniline, polypyrrole or polythiophene. Or a derivative of an aniline derivative, a pyrrole derivative or a thiophene derivative. Such as polyethylene dioxythiophene or poly 2,5-dimethoxyaniline. The metal element may be copper, silver or palladium or the like.

In the sixth step, referring to FIG. 4 to FIG. 6 , an electroplated metal layer 130 is formed on the surface of the conductive trace film 121 by electroplating. The electroplated metal layer 130 and the conductive trace film 121 together form the conductive trace 140. Circuit board 100.

Specifically, a plating barrier layer 150 may be formed on the surface of the substrate 110, and an opening 151 corresponding to the conductive wiring film 121 is formed in the plating barrier layer 150 such that the conductive wiring film 121 is exposed from the opening 151. The plating barrier layer 150 may be formed by printing a photoresist. Then, a plating metal layer 130 is formed on the surface of the hardened conductive wiring film 121 by electroplating. Due to the hardening guide The electric wiring film 121 has electrical conductivity, so that the hardened conductive wiring film 121 is plated with metal to form the electroplated metal layer 130. Finally, the plating barrier layer 150 is removed. The plated metal layer 130 may be a metal copper layer.

After this step, the step of forming a solder resist layer on the surface of the circuit board 100 may be further included.

Referring to FIG. 6 , the technical solution further provides a circuit board 100 including a substrate 110 and a conductive line 140 formed on the surface of the substrate 110 . The conductive line 140 includes a conductive line film 121 and a plated metal layer 130. The conductive line film 121 is formed between the substrate 110 and the plated metal layer 130. The conductive line film 121 includes a conductive polymer material and a metal element. The metal element is uniformly dispersed in the conductive polymer material. The conductive polymer is used to carry a metal element and the conductive line film 121 is tightly bonded to the substrate 110. The conductive polymer may be polyaniline, polypyrrole or polythiophene. Or a derivative of an aniline derivative, a pyrrole derivative or a thiophene derivative. Such as polyethylene dioxythiophene or poly 2,5-dimethoxyaniline. The metal element may be copper, silver or palladium or the like.

It can be understood that the circuit board manufacturing method provided by the technical solution can also be applied to the fabrication of a multi-layer circuit board, and only needs to press the insulating layer on one side of the conductive line 140, and then, in the insulating layer according to the method of manufacturing the conductive line 140. The surface can be made of conductive lines.

According to the circuit board and the manufacturing method thereof, the monomer of the conductive polymer and the precursor including the metal ion are coated on the surface of the substrate, and are irradiated with ultraviolet light to be cured into a conductive line film. The conductive line film comprises a conductive polymer material and a metal element, and has good electrical conductivity, and can form a plated metal layer directly on the surface thereof as a subsequent step. Therefore, the manufacturing method of the circuit board provided by the technical solution, When making conductive lines, exposure, development, and etching are not required, thereby avoiding the use of a large amount of chemical reagents and requiring a large amount of water resources. Therefore, the circuit board manufacturing method provided by the technical solution can reduce environmental pollution and reduce the production cost of the circuit board.

Further, in the technical solution, the formation of the conductive line film only needs to be irradiated with ultraviolet light, and does not require high-temperature baking treatment, thereby avoiding damage of the insulating layer in the substrate during high-temperature baking. 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.

110‧‧‧Substrate

121‧‧‧ Conductive film

130‧‧‧Electroplated metal layer

140‧‧‧Electrical circuit

100‧‧‧ boards

Claims (5)

A method for manufacturing a circuit board, comprising the steps of: providing a conductive polymer monomer and a soluble metal salt solution; uniformly mixing the conductive polymer monomer and a soluble metal salt solution to obtain a precursor; providing a substrate; and using the precursor The body is coated on the surface of the substrate to form a conductive line pattern; the conductive line pattern is irradiated with ultraviolet light to harden it, and the conductive polymer monomer is polymerized to obtain a conductive polymer, and the metal ion of the metal salt is Reducing to a simple metal material to obtain a conductive wiring film; and forming a plating metal layer on the surface of the conductive wiring film, the plating metal layer and the conductive wiring film forming a conductive path. The method for producing a circuit board according to the first aspect of the invention, wherein the conductive polymer monomer is a derivative of aniline, pyrrole, thiophene or aniline, a pyrrole derivative or a thiophene derivative. The method for producing a circuit board according to the first aspect of the invention, wherein the conductive polymer monomer is 3,4-ethylenethiophene or 2,5-dimethoxyaniline. The method of fabricating a circuit board according to claim 1, wherein the ultraviolet light has a wavelength ranging from 330 nm to 400 nm. The method of manufacturing a circuit board according to the first aspect of the invention, wherein the precursor is applied to a surface of the substrate by screen printing, inkjet printing or spin coating.