TW202135609A - Low-cost and high-process-capability printed circuit board manufacturing method - Google Patents

Abstract

The invention belongs to the technical field of printed circuit board manufacturing, and relates to a low-cost and high-process-capability printed circuit board manufacturing method. The method comprises the steps of copper electroplating, dielectric layer lamination, board disassembly and subsequent processing. According to the invention, the copper is electroplated on the surface of the metal conductive plate, and then the copper surface is roughened or adhered to the dielectric layer after being bonded with the bonding agent, so that the bonding force is ensured, the cost is reduced, and the process capability is improved.

Description

Low-cost and high-process capability printed circuit board manufacturing method and structure

The invention relates to the technical field of printed circuit board manufacturing, in particular to a low-cost and high-process capability printed circuit board manufacturing method and structure.

Traditionally, multilayer printed circuit boards have been manufactured using copper clad laminates with dielectric laminated copper foils. This copper-clad laminate is obtained by hot-pressing copper foil processing on the surface of the B-stage resin material (insulating film) of the substrate.

Generally, the cost of using 3um thin copper foil for hot pressing to achieve fine lines is relatively high, and the copper foil purchased out is generally in the shape of a coil, which needs to be cut and used, which will cause greater waste.

Therefore, it is necessary to develop a new printed circuit board manufacturing method to solve the above problems.

The main purpose of the present invention is to provide a low-cost and high-process-capable printed circuit board manufacturing method and structure, which can reduce the cost of copper foil and improve the process capability, and can ensure the bonding force.

The present invention achieves the above objectives through the following technical solutions: a low-cost and high-process capability printed circuit board manufacturing method, the steps of which include:

①Plating copper: electroplating a copper layer with a thickness of 1-10um on the surface of the metal conductive plate;

②Media lamination: After roughening the copper surface or applying bonding agent, let the copper surface and the dielectric layer be hot-compressed;

③Removing the board: Remove the metal conductive board, and leave the copper layer on the surface of the dielectric layer;

④ Subsequent processing: blind holes, drilling, degumming, blind AOI, degumming copper, pattern wiring, pattern plating, and wiring etching processes are performed on the copper layer to form a new wiring layer.

The present invention achieves the above objectives through the following technical solutions: a low-cost and high-process-capable printed circuit board structure, including: a copper layer, the thickness of the copper layer is 1-10um, and the copper surface of the copper layer is roughened Processing or coating bonding agent; and a dielectric layer, the dielectric layer and the copper surface are hot-compressed, and the copper layer is blind hole, drilled, glued, blind hole AOI, debonded copper, patterned circuit, pattern Electroplating and circuit etching process to form a new circuit layer. It further includes a metal conductive plate, and the copper layer is electroplated on the surface of the metal conductive plate.

Specifically, the roughening treatment in step ② includes browning, blackening, super-roughening, medium-roughening or micro-etching.

Further, the roughness of the copper surface is controlled: Ra value is 0.1～0.4um, Rz value is 1.0～5.0um.

Specifically, the temperature of applying the bonding agent is controlled at 25-90° C., and the thickness is 1-100 nm.

Specifically, the dielectric layer is a semi-cured resin film and a cured resin film of PP, PI, epoxy resin, LCP, and ceramic substrate.

Using the above technical solution, the beneficial effects of the technical solution of the present invention are:

In the present invention, copper is first electroplated on the surface of the metal conductive plate, and then the copper surface is roughened or the bonding agent is attached to the dielectric layer, which not only ensures the bonding force, but also reduces the cost and improves the process capability.

The present invention will be further described in detail below in conjunction with specific embodiments.

Example 1:

Follow the steps below to manufacture printed circuit boards:

①Plating a copper layer 2 with a thickness of 1-10um on the surface of the metal conductive plate 1. As shown in Figure 1, because the copper layer 2 will adhere to the surface of the metal conductive plate 1, the structure of the metal conductive plate 1 can be designed according to the structure of the circuit board. The copper layer 2 structure generated after electroplating can be the same as the dielectric layer. The structure of 4 matches.

② Apply bonding agent 3 (coupling agent) to the surface of the copper layer 2, as shown in Figure 2(a), and then heat and press the copper surface of the bonding agent 3 with the dielectric layer 4, as shown in Figure 2(b) . Low-cost metal surface treatment to obtain reliable bonding force.

③Remove the metal conductive plate 1 and leave the copper layer 2 on the surface of the dielectric layer 4. As shown in Figure 2(c), the laminated metal conductive plate 1 is a redundant part, which can be separated and recycled from the circuit board, and then a new round of electroplating process can be carried out.

④ Perform blind holes, drilling, de-glue, blind AOI, de-glue copper, pattern lines, pattern electroplating, circuit etching and other processes on the copper layer 2 to form a new circuit layer. The circuit board to which the copper layer 2 has been attached is processed in accordance with the conventional circuit technology.

The material of the above dielectric layer 4 can include, but is not limited to, PP (epoxy resin plus glass fiber cloth or epoxy resin semi-cured resin film, commonly known as Pre-pregnant), PI (polyimide film, polyimide film), epoxy Resin, LCP (Liquid Crystal Polymer), semi-cured (B-stage) resin film and cured (C-stage) resin film of ceramic substrate.

Example 2:

Follow the steps below to manufacture printed circuit boards:

① The surface of the metal conductive plate 1 is electroplated with a copper layer 2 with a thickness of 1-10um, as shown in Figure 1.

② Carry out browning and roughening reactions on the surface of the copper layer 2 to form a rough surface, and the copper surface and the dielectric layer 4 are hot-pressed and bonded. Roughness control: Ra value is 0.1～0.4um, Rz value is 1.0～5.0um. In this way, the roughness of the copper surface can meet the requirements, and the copper surface will not become too uneven and affect the quality of the circuit. As shown in Figure 3(a), the browning makes the surface of the copper layer 2 formed after electroplating present a fine uneven structure, so that the bonding force with the dielectric layer 4 can be improved during hot pressing, as shown in Figure 3(b) Show.

③Remove the metal conductive plate 1, leaving the copper layer 2 on the surface of the dielectric layer 4, as shown in Figure 3(c).

④ Perform blind holes, drilling, de-glue, blind AOI, de-glue copper, pattern lines, pattern electroplating, circuit etching and other processes on the copper layer 2 to form a new circuit layer.

The purpose of step ② is to obtain a copper surface with a certain roughness, so it can also be replaced by blackening, super-roughening, medium-roughening or micro-etching.

Example 3:

Follow the steps below to manufacture printed circuit boards:

①Plating a copper layer 2 with a thickness of 1-10um on the surface of the metal conductive plate 1, as shown in Figure 1.

② Carry out browning reaction on the surface of the copper layer 2 to form a rough surface. The roughness control: Ra value is 0.1～0.4um, Rz value is 1.0～5.0um. As shown in Figure 4(a), the browning makes the surface of the copper layer 2 formed after electroplating present a fine uneven structure, which helps to increase the bonding area between the bonding agent 3 and the copper surface and ensure the bonding force after pressing.

③ Coat the bonding agent 3 on the browning surface, as shown in Figure 4(b), and then combine the copper surface of the bonding agent 3 with the dielectric layer 4, as shown in Figure 4(c).

④Remove the metal conductive plate 1 and leave the copper layer 2 on the surface of the dielectric layer 4, as shown in Figure 4(d).

⑤ The copper layer 2 is subjected to processes such as blind holes, drilling, degumming, blind hole AOI, degumming copper, pattern lines, pattern plating, and line etching to form a new circuit layer.

This method dispenses with the process of hot pressing copper foil on the dielectric layer 4. Instead, the required copper layer 2 is first electroplated on the metal conductive plate 1, and then the copper surface is browned or coated with bonding agent 3, and then transferred to On the dielectric layer 4. In this way, the cost of increasing the copper layer 2 is only equivalent to 1/5 to 1/4 of that of the hot-pressed 3um thin copper foil, which significantly reduces the investment. The bonding force between the copper layer 2 and the dielectric layer 4 can be ensured by roughening the copper surface or a bonding agent, and the adhesion of the copper layer 2 to the dielectric layer 4 can be realized at low cost.

What has been described above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can be made, and these all fall within the protection scope of the present invention.

1: Metal conductive plate 2: Copper layer 3: Bonding agent 4: Dielectric layer

Figure 1 is a schematic cross-sectional view of a metal conductive plate after copper electroplating. Figure 2(a) is a schematic cross-sectional view of the copper surface of Example 1 after being coated with a bonding agent. Figure 2(b) is a schematic cross-sectional view of Example 1 after the media is laminated. Figure 2(c) is a cross-sectional view of the circuit board after the metal conductive plate of Example 1 is removed. Fig. 3(a) is a schematic cross-sectional view of the copper surface of Example 2 after roughening. Figure 3(b) is a schematic cross-sectional view of Example 2 after the media is laminated. Fig. 3(c) is a cross-sectional view of the circuit board after the metal conductive plate of Example 2 is disassembled. 4(a) is a schematic cross-sectional view of the copper surface of Example 3 after roughening. Fig. 4(b) is a schematic cross-sectional view of the copper surface of Example 3 after being coated with a bonding agent. Figure 4(c) is a schematic cross-sectional view of Example 3 after the media is laminated. Fig. 4(d) is a cross-sectional view of the circuit board after the metal conductive plate of Example 3 is removed.

1: Metal conductive plate

2: Copper layer

3: Bonding agent

4: Dielectric layer

Claims (11)

A low-cost and high-process capability printed circuit board manufacturing method, the steps include: ①Plating copper: electroplating a copper layer with a thickness of 1-10um on the surface of the metal conductive plate; ②Media lamination: After roughening the copper surface or applying bonding agent, let the copper surface and the dielectric layer be hot-compressed; ③Removing the board: Remove the metal conductive board, and leave the copper layer on the surface of the dielectric layer; ④ Subsequent processing: blind holes, drilling, degumming, blind AOI, degumming copper, pattern wiring, pattern plating, and wiring etching processes are performed on the copper layer to form a new wiring layer. The method for manufacturing a printed circuit board with low cost and high process capability as described in claim 1, wherein the roughening treatment includes browning, blackening, super-roughening, medium-roughening or micro-etching. The low-cost and high-process-capability printed circuit board manufacturing method according to claim 2, wherein the roughness of the copper surface is controlled: Ra value is 0.1-0.4um, Rz value is 1.0-5.0um. The low-cost and high-process-capability printed circuit board manufacturing method according to claim 1, wherein the temperature of applying the bonding agent is controlled at 25-90°C and the thickness is 1-100 nm. The low-cost and high-process-capable printed circuit board manufacturing method according to claim 1, wherein the dielectric layer is a semi-cured resin film and a cured resin film of PP, PI, epoxy, LCP, and ceramic substrates. A printed circuit board structure with low cost and high process capability, including: A copper layer, the thickness of the copper layer is 1-10um, the copper surface of the copper layer is roughened or coated with a bonding agent; and A dielectric layer, the dielectric layer and the copper surface are thermally pressed and combined, and the copper layer is subjected to blind holes, drilling, degumming, blind AOI, degumming copper, pattern lines, pattern plating, and line etching processes, and Form a new circuit layer. The low-cost and high-process capability printed circuit board structure described in claim 6 further includes a metal conductive plate, and the copper layer is electroplated on the surface of the metal conductive plate. The printed circuit board structure with low cost and high process capability according to claim 6, wherein the roughening treatment includes browning, blackening, super roughening, medium roughening or micro-etching. The low-cost and high-process-capable printed circuit board structure according to claim 8, wherein the roughness of the copper surface is controlled: Ra value is 0.1-0.4um, Rz value is 1.0-5.0um. The low-cost and high-process-capability printed circuit board structure according to claim 6, wherein the temperature of applying the bonding agent is controlled at 25-90° C., and the thickness is 1-100 nm. The printed circuit board structure with low cost and high process capability as described in claim 6, wherein the dielectric layer is a semi-cured resin film and a cured resin film of PP, PI, epoxy resin, LCP, ceramic substrate.

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