TW202045752A - Method for forming a copper layer on a circuit board and a circuit board having a sputtered copper layer - Google Patents

Abstract

The present invention provides a method for forming a copper layer on a circuit board, including: providing a circuit board structure having a to-be-plated surface, the to-be-plated surface having conductive regions and non-conductive regions; and sputtering the to-be-plated surface to form a sputtered copper layer on the conductive and non-conductive regions of the to-be-plated surface. The present invention can replace the chemical plating process in the conventional circuit board process.

Description

Method for forming copper layer on circuit board and circuit board with sputtered copper layer

The invention relates to a circuit board technology, in particular to a manufacturing process and structure of a circuit board copper layer.

In the existing circuit board manufacturing process, it is generally necessary to form a copper layer on the substrate by means of electroless plating or electroplating, and the formed copper layer can be further made into a patterned circuit later. Compared with electroplating, electroless plating has its advantage in that after proper surface treatment, a thin layer of copper can be plated on the surface of non-conductors. This feature greatly increases the freedom of circuit setting and is widely used in circuits. The board is in process.

However, electroless copper plating also has its disadvantages in that the composition of the plating solution is more complicated, the process is more difficult, and the cost of electroless copper plating is also higher.

In view of this, the main purpose of the present invention is to provide another alternative method and structure for forming a copper layer on a circuit board.

In order to achieve the above and other objectives, the present invention provides a method for forming a copper layer on a circuit board, which includes:

Providing a circuit board structure having a surface to be plated, the surface to be plated having conductive areas and non-conductive areas; and

Sputtering is performed on the surface to be plated, and a sputtered copper layer is formed on the conductive area and the non-conductive area of the surface to be plated.

In order to achieve the above and other objectives, the present invention provides a circuit board with a sputtered copper layer, which includes a circuit board structure and a sputtered copper layer. The circuit board structure has a surface to be plated, and the surface to be plated has a conductive area and a non-conductive area. In the conductive area, the sputtered copper layer is formed in the conductive area and the non-conductive area of the surface to be plated.

Through the above technology, the present invention can physically deposit copper ions on the surface to be plated, and the diffraction performance of copper ions is good, and can sputter the surface to be plated with complex shapes, so that the conductive and non-conductive areas of the surface to be plated can be sputtered. The copper layer is formed, which can replace the electroless plating process in the conventional circuit board manufacturing process, reduce the use of plating solution, and have the opportunity to reduce costs.

The present invention discloses a method for forming a copper layer on a circuit board and a circuit board with a sputtered copper layer. The method is widely compatible with the copper layer setting process in the existing circuit board manufacturing process, and is particularly capable of replacing electroless copper plating Process.

Hereinafter, the manufacturing process of one embodiment of the present invention will be described with reference to FIGS. 1-7.

Please refer to Figure 1. First, a circuit board structure 1 is provided. The circuit board structure 1 has a surface 11 to be plated. The surface 11 to be plated has conductive areas 111 and non-conductive areas 112, and the number of conductive areas and non-conductive areas 112 Depending on the circuit design, in a circuit board structure with high circuit design complexity, the surface to be plated 11 may have a large number of conductive areas 111 and non-conductive areas 112. It is understandable that when the circuit board structure has a higher circuit complexity, the surface of the surface to be plated is generally rougher, and the height of the conductive area and the non-conductive area may not be the same. The conductive area 111 is, for example, a lower circuit layer that has been prefabricated with some circuits in the circuit board structure, such as a copper lower circuit copper layer. The non-conductive area 112 is, for example, a dielectric layer, a solder mask, or an encapsulant in a circuit board structure, such as polyimide, epoxy, or other resins commonly used in circuit board structures. The circuit board structure exemplified in this embodiment is a single-sided, single-layer board. In other possible implementation manners, the applicable circuit board structure may also be a double-sided board or a multi-layer board.

Please refer to Figure 2 to perform a sputtering process on the surface 11 to be plated to form a sputtered copper layer 20 on the conductive area 111 and the non-conductive area 112 of the surface to be plated 11. Under vacuum conditions, using low-pressure, high-current arc discharge technology, the copper atoms in the copper target are bombarded by the plasma to leave the copper target through gas discharge, and the acceleration of electrons is used to make the splashed Copper atoms are deposited on the surface 11 to be plated. Because the sputtered copper atoms have good diffraction ability, a thin layer of copper can be deposited on the irregular surface of the surface 11 to be plated, thereby making the conductive area 111 and non-conductive All regions 112 can form a sputtered copper layer 20.

Please refer to Figure 3, the sputtered copper layer 20 is electroplated to form an electroplated copper layer 30 on the sputtered copper layer 20. The electroplating process uses the principle of electrolysis to add a layer of copper to the sputtered copper layer 20. To increase the thickness of the overall copper layer.

Then, the sputtered copper layer 20 and the electroplated copper layer 30 can be further patterned to form a patterned circuit. The graphical processing is exemplarily shown in Figures 4 to 7.

First, referring to FIG. 4, a photoresist layer 40 is formed on the electroplated copper layer 30, and the photoresist layer 40 is selectively irradiated and exposed.

Next, as shown in FIG. 5, the partial photoresist layer 40 is selectively removed with a developing solution, and the underlying electroplated copper layer 30 is exposed.

Then, as shown in FIG. 6, the exposed copper electroplating layer 30 and the sputtered copper layer 20 underneath are selectively removed with an etching solution, so that the sputtered copper layer 20 and the electroplated copper layer 30 are patterned.

Finally, as shown in Figure 7, the photoresist layer is removed, and the resulting circuit board includes the circuit board structure 1 and the patterned sputtered copper layer 20 and the electroplated copper layer 30. Finally, the sputtered copper layer 20 is formed On partial surfaces of the conductive area 111 and the non-conductive area 112 on the surface 11 of the circuit board structure 1 to be plated, the electroplated copper layer 30 covers the sputtered copper layer 20. According to the required circuit design, the circuit board shown in Figure 7 can be further added with layers, solder resist treatment, surface treatment and/or other conventional post-processing in the circuit board manufacturing process.

Through the above technology, the present invention can physically deposit copper ions on the surface to be plated, and the diffraction performance of copper ions is good, and can sputter the surface to be plated with complex shapes, so that the conductive and non-conductive areas of the surface to be plated can be sputtered. The copper layer is formed, which can replace the electroless plating process in the conventional circuit board manufacturing process, reduce the use of plating solution, and have the opportunity to reduce costs.

1: Circuit board structure 11: to be plated 111: conductive area 112: Non-conductive area 20: Sputtered copper layer 30: Electroplated copper layer 40: photoresist layer

Figures 1-7 are schematic diagrams of the manufacturing process of one embodiment of the present invention.

1: Circuit board structure

11: to be plated

111: conductive area

112: Non-conductive area

20: Sputtered copper layer

30: Electroplated copper layer

Claims (7)

A method for forming a copper layer on a circuit board includes: providing a circuit board structure having a surface to be plated, the surface to be plated having a conductive area and a non-conductive area; and sputtering the surface to be plated After treatment, a sputtered copper layer is formed on the conductive area and the non-conductive area of the surface to be plated. The method for forming a copper layer on a circuit board according to claim 1, further comprising: electroplating the sputtered copper layer, and forming an electroplated copper layer on the sputtered copper layer. The method for forming a copper layer on a circuit board as described in claim 2, further comprising: performing image processing on the sputtered copper layer and the electroplated copper layer. The method for forming a copper layer on a circuit board according to any one of claims 1 to 3, wherein the material of the non-conductive area is polyimide. The method for forming a copper layer on a circuit board according to any one of claims 1 to 3, wherein the material of the non-conductive area is resin. A circuit board with a sputtered copper layer, comprising: a circuit board structure with a surface to be plated, the surface to be plated with a conductive area and a non-conductive area; and a sputtered copper layer formed on the conductive surface to be plated Area and non-conductive area. According to claim 6, the circuit board with a sputtered copper layer further includes an electroplated copper layer formed on the sputtered copper layer.

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