Lead-free electrogilding and chemical gilding printed circuit board and manufacturing method thereof

Abstract

The invention relates to a leadless electrogilding and chemical gilding printed circuit board and a manufacturing method thereof. The leadless electrogilding and chemical gilding printed circuit board comprises a substrate, an epoxy resin base material, a substrate upper layer copper foil, a substrate lower layer copper foil, a first prepreg, a second prepreg, a first press-fit copper foil, a second press-fit copper foil, a first communication column, a second communication column, an electrogilding layer and a chemical gilding layer, the manufacturing method comprises the steps of hole drilling, copper plating in holes, hole plugging with resin, surface copper plating, circuit pattern etching, pressing, laser hole drilling, copper filling in holes, circuit pattern etching, electrogilding, circuit pattern etching and chemical gilding. The printed circuit board provided by the invention can meet different surface treatment patch and contact modes, so that a product has better performance, and various requirements of customers and consumers are met. According to the manufacturing method, traditional manufacturing equipment can be used, production of high-precision printed circuit boards is achieved, production cost is reduced, and product benefits are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of printed circuit boards, and specifically discloses a lead-free gold-plated and gold-plated printed circuit board and a manufacturing method thereof. Background Art

[0002] With the diversification and lightweight demand for electronic products, traditional printed circuit boards can no longer achieve different surface treatment patches and contact methods, and thus cannot meet the diverse needs of customers and consumers. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a lead-free gold-plated and gold-plated printed circuit board and a manufacturing method thereof.

[0004] According to the technical solution provided by the present invention, the leadless gold-plated and chemically gold-plated printed circuit board includes a substrate, a first prepreg, a second prepreg, a first pressed copper foil, a second pressed copper foil, a first connecting column, a second connecting column, an electroplated gold layer and a chemically gold-plated layer, wherein the substrate includes an epoxy resin substrate, an upper copper foil of the substrate located on the upper surface of the epoxy resin substrate, and a lower copper foil of the substrate located on the lower surface of the epoxy resin substrate; A through hole is opened on the substrate, and a copper layer is provided on the inner wall of the through hole. The copper layer electrically connects the upper copper foil of the substrate with the lower copper foil of the substrate, and a resin column is provided in the copper layer. A plurality of first prepreg layers are provided above the substrate. A first laminated copper foil is provided on the upper surface of each first prepreg layer. Circuit patterns are provided on the first laminated copper foil and the upper copper foil of the substrate. First communication holes are provided on the first prepreg and the upper first laminated copper foil. First communication pillars are provided in the first communication holes. An electroplated gold layer is provided on the upper surface of each first communication pillar. Adjacent electroplated gold layers and the lowermost electroplated gold layer and the upper copper foil of the substrate are electrically connected via the first communication pillars. Several layers of second prepregs are provided below the substrate 1, and a layer of second laminated copper foil is provided on the lower surface of each layer of the second prepreg. Circuit patterns are provided on the second laminated copper foil and the copper foil below the substrate. Second connecting holes are provided on the second prepreg and the second laminated copper foil below it. Second connecting columns are provided in the second connecting holes. A chemical gold-plated layer is provided on the lower surface of each second connecting column. Adjacent chemical gold-plated layers and between the uppermost chemical gold-plated layer and the copper foil below the substrate are electrically connected through the second connecting columns.

[0005] A leadless gold-plated and chemically plated printed circuit board comprises a substrate assembly, a first prepreg, a second prepreg, a first pressed copper foil, a second pressed copper foil, a first connecting post, a second connecting post, an electroplated gold layer, and a chemically plated gold layer. The substrate assembly comprises at least two substrates, with two adjacent substrates connected via a third prepreg. The substrates comprise an epoxy resin substrate, an upper copper foil located on the upper surface of the epoxy resin substrate, and a lower copper foil located on the lower surface of the epoxy resin substrate. A through hole is opened on the substrate assembly, and a hole copper layer is provided on the inner wall of the through hole. The hole copper layer electrically connects all the upper copper foils of the substrate with all the lower copper foils of the substrate, and a resin column is provided in the hole copper layer; A plurality of first prepreg layers are provided above the substrate assembly. A first laminated copper foil is provided on the upper surface of each first prepreg layer. Circuit patterns are provided on the first laminated copper foil and the upper copper foil of the substrate. First communication holes are provided on the first prepreg and the upper first laminated copper foil. First communication pillars are provided in the first communication holes. An electroplated gold layer is provided on the upper surface of each first communication pillar. Adjacent electroplated gold layers and between the lowermost electroplated gold layer and the uppermost copper foil of the substrate are electrically connected via the first communication pillars. Several layers of second prepregs are provided below the substrate, a layer of second pressed copper foil is provided on the lower surface of each layer of the second prepreg, circuit patterns are provided on the second pressed copper foil and the copper foil below the substrate, second connecting holes are provided on the second prepreg and the second pressed copper foil below it, second connecting columns are provided in the second connecting holes, a chemical gold-plated layer is provided on the lower surface of each second connecting column, and adjacent chemical gold-plated layers and between the uppermost chemical gold-plated layer and the copper foil below the substrate are electrically connected through the second connecting columns.

[0006] The manufacturing method of the above-mentioned leadless gold-plated and gold-plated printed circuit board comprises the following steps: S1. Providing a substrate, the substrate comprising an epoxy resin substrate, an upper copper foil of the substrate located on the upper surface of the epoxy resin substrate, and a lower copper foil of the substrate located on the lower surface of the epoxy resin substrate; S2, drilling a through hole on the substrate through a mechanical drilling process; S3, copper plating is performed on the front, back, side surfaces and inner walls of the through-holes of the substrate through a copper electroplating process, so that the upper copper foil and the lower copper foil of the substrate become thicker, and a hole copper layer is formed on the inner wall of the through-hole, and the hole copper layer electrically connects the upper copper foil of the substrate and the lower copper foil of the substrate; S4, forming a resin column in the hole copper layer through a resin plugging process; S5. Copper is plated on the front, back, and side surfaces of the substrate through a copper electroplating process to thicken the upper copper foil and the lower copper foil of the substrate. The upper copper foil of the substrate covers the upper end surface of the resin column, and the lower copper foil of the substrate covers the lower end surface of the resin column. Circuit patterns are etched on the upper copper foil and the lower copper foil of the substrate. S6. Take the first prepreg, the second prepreg, the first pressed copper foil, and the second pressed copper foil, and stack and press the first pressed copper foil, the first prepreg, the substrate, the second prepreg, and the second pressed copper foil together in order from top to bottom to form a semi-finished printed circuit board; S7. Laser drilling a first connecting hole through the first pressed copper foil and the first prepreg to expose the upper surface of the upper copper foil of the substrate within the upper end surface of the resin column. Laser drilling a second connecting hole through the second pressed copper foil and the second prepreg to expose the lower surface of the lower copper foil of the substrate within the lower end surface of the resin column. S8, filling the first and second communicating holes with copper by an electroplating filling process to form first and second communicating columns, wherein the first communicating columns electrically connect the first pressed copper foil to the upper copper foil of the substrate, and the second communicating columns electrically connect the second pressed copper foil to the lower copper foil of the substrate; S9, first protecting the position of the first laminated copper foil that needs to be retained with a dry film, protecting the entire second laminated copper foil with a dry film, then etching a circuit pattern on the first laminated copper foil, and finally removing the dry film; S10, first protecting the first pressed copper foil on the outer side above the first connecting pillar with a dry film, and protecting the entire second pressed copper foil with a dry film, so that the first pressed copper foil above the first connecting pillar is exposed, then forming an electroplated gold layer on the first pressed copper foil above the first connecting pillar through a gold electroplating process, and finally removing the dry film; S11, first protecting the position of the second pressed copper foil that needs to be retained with a dry film, protecting the first pressed copper foil and the electroplated gold layer as a whole with a dry film, then etching a circuit pattern on the second pressed copper foil, and finally removing the dry film; S12, first protecting the second pressed copper foil on the outer side below the second connecting pillar with a dry film, and protecting the first pressed copper foil and the electroplated gold layer as a whole with a dry film, so that the second pressed copper foil below the second connecting pillar is exposed, then forming a chemical gold-plated layer on the second pressed copper foil below the second connecting pillar through a chemical gold plating process, and finally removing the dry film; S13, taking the first prepreg, the second prepreg, the first pressed copper foil, and the second pressed copper foil, and stacking and pressing the first pressed copper foil, the first prepreg, the semi-finished printed circuit board, the second prepreg, and the second pressed copper foil together in order from top to bottom; S14, machining a first communicating hole through a laser drilling process in the first pressed copper foil and the first prepreg located at the top, thereby exposing a portion of the upper surface of the first pressed copper foil located below the first prepreg located at the top; machining a second communicating hole through a laser drilling process in the second pressed copper foil and the second prepreg located at the bottom, thereby exposing a portion of the lower surface of the second pressed copper foil located above the second prepreg located at the bottom; S15, filling the first and second communicating holes with copper through an electroplating filling process to form first and second communicating columns, so that the two uppermost layers of the first pressed copper foil are electrically connected through the first connecting columns, and the two lowermost layers of the second pressed copper foil are electrically connected through the second connecting columns; S16, first protecting the position of the first laminated copper foil that needs to be retained with a dry film, protecting the entire second laminated copper foil with a dry film, then etching a circuit pattern on the first laminated copper foil, and finally removing the dry film; S17, first protecting the outer side of the first pressed copper foil above the first connecting pillar with a dry film, and protecting the entire second pressed copper foil with a dry film, so that the first pressed copper foil above the first connecting pillar is exposed, then forming an electroplated gold layer on the first pressed copper foil above the first connecting pillar through a gold electroplating process, and finally removing the dry film; S18, first protecting the position of the second pressed copper foil that needs to be retained with a dry film, protecting the first pressed copper foil and the electroplated gold layer as a whole with a dry film, then etching a circuit pattern on the second pressed copper foil, and finally removing the dry film; S19, first protecting the second pressed copper foil on the outer side below the second connecting pillar with a dry film, and protecting the first pressed copper foil and the electroplated gold layer as a whole with a dry film, so that the second pressed copper foil below the second connecting pillar is exposed, then forming a chemical gold-plated layer on the second pressed copper foil below the second connecting pillar through a chemical gold plating process, and finally removing the dry film; S20, repeating steps S13 to S19 for a specified number of times as required; S21, obtaining a finished printed circuit board.

[0007] The manufacturing method of the above-mentioned leadless gold-plated and gold-plated printed circuit board comprises the following steps: S1. Providing a substrate assembly, the substrate assembly comprising at least two substrates 1, wherein two adjacent substrates 1 are connected via a third prepreg, the substrates 1 comprising an epoxy resin substrate, an upper substrate copper foil located on an upper surface of the epoxy resin substrate, and a lower substrate copper foil located on a lower surface of the epoxy resin substrate, wherein the uppermost substrate copper foil and the lowermost substrate copper foil are not etched with a circuit pattern, and the remaining upper substrate copper foils and lower substrate copper foils are pre-etched with circuit patterns; S2, drilling through holes on the substrate assembly through a mechanical drilling process; S3, copper plating is performed on the front, back, side surfaces, and inner walls of the through-holes of the substrate assembly through a copper electroplating process, so that the upper copper foil of the substrate at the top and the lower copper foil of the substrate at the bottom become thicker, and a hole copper layer is formed on the inner wall of the through-hole, and the hole copper layer electrically connects all the upper copper foils of the substrate and all the lower copper foils of the substrate; S4, forming a resin column in the hole copper layer through a resin plugging process; S5. Copper is plated on the front, back, and side surfaces of the substrate 1 through a copper electroplating process to thicken the upper copper foil and the lower copper foil of the substrate. The upper copper foil of the substrate covers the upper end surface of the resin column, and the lower copper foil of the substrate covers the lower end surface of the resin column. A circuit pattern is etched on the upper copper foil located at the top and the lower copper foil located at the bottom. S6. Take the first prepreg, the second prepreg, the first pressed copper foil, and the second pressed copper foil, and stack and press the first pressed copper foil, the first prepreg, the substrate assembly, the second prepreg, and the second pressed copper foil together in order from top to bottom to form a semi-finished printed circuit board; S7. Laser drilling a first connecting hole through the first pressed copper foil and the first prepreg to expose the upper surface of the upper copper foil of the substrate within the upper end surface of the resin column. Laser drilling a second connecting hole through the second pressed copper foil and the second prepreg to expose the lower surface of the lower copper foil of the substrate within the lower end surface of the resin column. S8, filling the first and second communicating holes with copper by an electroplating filling process to form first and second communicating columns, wherein the first communicating columns electrically connect the first pressed copper foil to the upper copper foil of the substrate, and the second communicating columns electrically connect the second pressed copper foil to the lower copper foil of the substrate; S9, first protecting the position of the first laminated copper foil that needs to be retained with a dry film, protecting the entire second laminated copper foil with a dry film, then etching a circuit pattern on the first laminated copper foil, and finally removing the dry film; S10, first protecting the first pressed copper foil on the outer side above the first connecting pillar with a dry film, and protecting the entire second pressed copper foil with a dry film, so that the first pressed copper foil above the first connecting pillar is exposed, then forming an electroplated gold layer on the first pressed copper foil above the first connecting pillar through a gold electroplating process, and finally removing the dry film; S11, first protecting the position of the second pressed copper foil that needs to be retained with a dry film, protecting the first pressed copper foil and the electroplated gold layer as a whole with a dry film, then etching a circuit pattern on the second pressed copper foil, and finally removing the dry film; S12, first protecting the second pressed copper foil on the outer side below the second connecting pillar with a dry film, and protecting the first pressed copper foil and the electroplated gold layer as a whole with a dry film, so that the second pressed copper foil below the second connecting pillar is exposed, then forming a chemical gold-plated layer on the second pressed copper foil below the second connecting pillar through a chemical gold plating process, and finally removing the dry film; S13, taking the first prepreg, the second prepreg, the first pressed copper foil, and the second pressed copper foil, and stacking and pressing the first pressed copper foil, the first prepreg, the semi-finished printed circuit board, the second prepreg, and the second pressed copper foil together in order from top to bottom; S14, machining a first communicating hole through a laser drilling process in the first pressed copper foil and the first prepreg located at the top, thereby exposing a portion of the upper surface of the first pressed copper foil located below the first prepreg located at the top; machining a second communicating hole through a laser drilling process in the second pressed copper foil and the second prepreg located at the bottom, thereby exposing a portion of the lower surface of the second pressed copper foil located above the second prepreg located at the bottom; S15, filling the first and second communicating holes with copper through an electroplating filling process to form first and second communicating columns, so that the two uppermost layers of the first pressed copper foil are electrically connected through the first connecting columns, and the two lowermost layers of the second pressed copper foil are electrically connected through the second connecting columns; S16, first protecting the position of the first laminated copper foil that needs to be retained with a dry film, protecting the entire second laminated copper foil with a dry film, then etching a circuit pattern on the first laminated copper foil, and finally removing the dry film; S17, first protecting the outer side of the first pressed copper foil above the first connecting pillar with a dry film, and protecting the entire second pressed copper foil with a dry film, so that the first pressed copper foil above the first connecting pillar is exposed, then forming an electroplated gold layer on the first pressed copper foil above the first connecting pillar through a gold electroplating process, and finally removing the dry film; S18, first protecting the position of the second pressed copper foil that needs to be retained with a dry film, protecting the first pressed copper foil and the electroplated gold layer as a whole with a dry film, then etching a circuit pattern on the second pressed copper foil, and finally removing the dry film; S19, first protecting the second pressed copper foil on the outer side below the second connecting pillar with a dry film, and protecting the first pressed copper foil and the electroplated gold layer as a whole with a dry film, so that the second pressed copper foil below the second connecting pillar is exposed, then forming a chemical gold-plated layer on the second pressed copper foil below the second connecting pillar through a chemical gold plating process, and finally removing the dry film; S20, repeating steps S13 to S19 for a specified number of times as required; S21, obtaining a finished printed circuit board.

[0008] Preferably, the thickness of the epoxy resin substrate is 20.3-304.8 microns, and the thickness of the upper copper foil of the substrate and the lower copper foil of the substrate are both 12-210 microns.

[0009] Preferably, the thickness of the first prepreg and the second prepreg are both 35-304.8 microns.

[0010] Preferably, the thickness of the third prepreg is 35-304.8 microns.

[0011] Preferably, the thickness of the first laminated copper foil and the second laminated copper foil are both 12-210 microns.

[0012] The printed circuit board of the present invention can meet the needs of different surface treatment patches and contact methods, so that the product has better performance, thereby meeting the diverse needs of customers and consumers.

[0013] The printed circuit board of the present invention, which can be used for a high-end writable mosaic camera module, is high-density assembled and super-interconnected, thereby realizing a small, delicate and precise printed circuit board.

[0014] The manufacturing method of the present invention can use traditional manufacturing equipment to achieve the production of high-precision printed circuit boards, reduce production costs, and improve product benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 1 is a structural diagram of the substrate provided in step S1 in Example 1.

[0016] Figure 2 This is a structural diagram of the substrate after processing in step S2 in Example 1.

[0017] Figure 3 This is a structural diagram of the substrate after processing in step S3 in Example 1.

[0018] Figure 4 This is a structural diagram of the substrate after processing in step S4 in Example 1.

[0019] Figure 5 This is a structural diagram of the substrate after being processed in step S5 in Example 1.

[0020] Figure 6 This is a structural diagram of the semi-finished printed circuit board after processing in step S6 in Example 1.

[0021] Figure 7 1 is a structural diagram of the semi-finished printed circuit board after processing in step S7 in Example 1.

[0022] Figure 81 is a structural diagram of the semi-finished printed circuit board after processing in step S8 in Example 1.

[0023] Figure 9 1 is a structural diagram of the semi-finished printed circuit board after being processed in step S10 in Example 1.

[0024] Figure 10 This is a structural diagram of the semi-finished printed circuit board after processing in step S12 in Example 1.

[0025] Figure 11 This is a structural diagram of the finished printed circuit board after processing in step S21 in Example 1.

[0026] Figure 12 It is a structural diagram of the substrate assembly provided in step S1 in Example 2.

[0027] Figure 13 This is a structural diagram of the substrate assembly after processing in step S2 in Example 2.

[0028] Figure 14 This is a structural diagram of the substrate assembly after processing in step S3 in Example 2.

[0029] Figure 15 This is a structural diagram of the substrate assembly after processing in step S4 in Example 2.

[0030] Figure 16 This is a structural diagram of the substrate assembly after processing in step S5 in Example 2.

[0031] Figure 17 This is a structural diagram of the semi-finished printed circuit board after processing in step S6 in Example 2.

[0032] Figure 18 FIG. 1 is a structural diagram of the semi-finished printed circuit board after processing in step S7 in Example 2.

[0033] Figure 19 This is a structural diagram of the semi-finished printed circuit board after processing in step S8 in Example 2.

[0034] Figure 20 This is a structural diagram of the semi-finished printed circuit board after processing in step S10 in Example 2.

[0035] Figure 21 This is a structural diagram of the semi-finished printed circuit board after processing in step S12 in Example 2.

[0036] Figure 22 This is a structural diagram of the finished printed circuit board after processing in step S21 in Example 2. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0038] Example 1 A printed circuit board without lead electroplating gold and gold, such as Figure 11 As shown, it includes a substrate 1, a first prepreg 2.1, a second prepreg 2.2, a first pressed copper foil 3.1, a second pressed copper foil 3.2, a first connecting column 4.1, a second connecting column 4.2, an electroplated gold layer 5.1 and a chemically plated gold layer 5.2. The substrate 1 includes an epoxy resin substrate 1.1, an upper copper foil 1.2 located on the upper surface of the epoxy resin substrate 1.1, and a lower copper foil 1.3 located on the lower surface of the epoxy resin substrate 1.1. A through hole is formed on the substrate 1, and a copper layer 1.4 is formed on the inner wall of the through hole. The copper layer 1.4 electrically connects the upper copper foil 1.2 of the substrate with the lower copper foil 1.3 of the substrate. A resin column 1.5 is formed in the copper layer 1.4. Several layers of first prepregs 2.1 are provided above a substrate 1. A first laminated copper foil 3.1 is provided on the upper surface of each first prepreg 2.1. Circuit patterns are provided on the first laminated copper foil 3.1 and the upper copper foil 1.2 of the substrate. First communication holes are provided in the first prepregs 2.1 and the upper laminated copper foil 3.1. First communication posts 4.1 are provided within the first communication holes. An electroplated gold layer 5.1 is provided on the upper surface of each first communication post 4.1. Adjacent electroplated gold layers 5.1, as well as the lowermost electroplated gold layer 5.1 and the upper copper foil 1.2 of the substrate, are electrically connected via the first communication posts 4.1. Several layers of second prepregs 2.2 are provided beneath the substrate 1. A layer of second laminated copper foil 3.2 is provided on the lower surface of each layer of second prepreg 2.2. Circuit patterns are provided on the second laminated copper foil 3.2 and the substrate's lower copper foil 1.3. Second communication holes are provided in the second prepregs 2.2 and the underlying second laminated copper foil 3.2. Second communication posts 4.2 are provided within the second communication holes. A chemically plated gold layer 5.2 is provided on the lower surface of each second communication post 4.2. Adjacent chemically plated gold layers 5.2, as well as the uppermost chemically plated gold layer 5.2 and the substrate's lower copper foil 1.3, are electrically connected via the second communication posts 4.2.

[0039] The method for manufacturing the above-mentioned leadless gold-plated and gold-plated printed circuit board comprises the following steps: S1. Provide a substrate 1, the substrate 1 including an epoxy resin substrate 1.1, an upper copper foil 1.2 located on the upper surface of the epoxy resin substrate 1.1, and a lower copper foil 1.3 located on the lower surface of the epoxy resin substrate 1.1. Figure 1 As shown; S2, drilling a through hole on the substrate 1 by mechanical drilling process, such as Figure 2 As shown; S3, copper is plated on the front, back, side and inner wall of the through hole of the substrate 1 by the copper electroplating process, so that the upper copper foil 1.2 of the substrate and the lower copper foil 1.3 of the substrate become thicker, and at the same time, a hole copper layer 1.4 is formed on the inner wall of the through hole, and the hole copper layer 1.4 electrically connects the upper copper foil 1.2 of the substrate and the lower copper foil 1.3 of the substrate. Figure 3 As shown; S4, forming a resin column 1.5 in the hole copper layer 1.4 through the resin plugging process, such as Figure 4 As shown; S5. Copper is plated on the front, back and side surfaces of the substrate 1 through a copper electroplating process to make the upper copper foil 1.2 and the lower copper foil 1.3 thicker. The upper copper foil 1.2 covers the upper end surface of the resin column 1.5, and the lower copper foil 1.3 covers the lower end surface of the resin column 1.5. Circuit patterns are etched on the upper copper foil 1.2 and the lower copper foil 1.3. Figure 5 As shown; S6. Take the first prepreg 2.1, the second prepreg 2.2, the first pressed copper foil 3.1 and the second pressed copper foil 3.2, and stack and press the first pressed copper foil 3.1, the first prepreg 2.1, the substrate 1, the second prepreg 2.2 and the second pressed copper foil 3.2 together in order from top to bottom to form a semi-finished printed circuit board. Figure 6 As shown; S7. A first connecting hole is formed on the first pressed copper foil 3.1 and the first prepreg 2.1 by laser drilling, so that the upper surface of the upper copper foil 1.2 of the substrate within the upper end surface of the resin column 1.5 is exposed. A second connecting hole is formed on the second pressed copper foil 3.2 and the second prepreg 2.2 by laser drilling, so that the lower surface of the lower copper foil 1.3 of the substrate within the lower end surface of the resin column 1.5 is exposed. Figure 7 As shown; S8, copper is filled in the first and second connecting holes by electroplating filling process to form first connecting pillars 4.1 and second connecting pillars 4.2. The first connecting pillars 4.1 electrically connect the first pressed copper foil 3.1 and the upper copper foil 1.2 of the substrate, and the second connecting pillars 4.2 electrically connect the second pressed copper foil 3.2 and the lower copper foil 1.3 of the substrate. Figure 8 As shown; S9, first protecting the position of the first laminated copper foil 3.1 that needs to be retained with a dry film, and protecting the entire second laminated copper foil 3.2 with a dry film, then etching a circuit pattern on the first laminated copper foil 3.1, and finally removing the dry film; S10, firstly, the first pressed copper foil 3.1 above the first connecting pillar 4.1 is protected with a dry film, and the second pressed copper foil 3.2 is protected with a dry film, so that the first pressed copper foil 3.1 above the first connecting pillar 4.1 is exposed, and then a gold plating layer 5.1 is formed on the first pressed copper foil 3.1 above the first connecting pillar 4.1 through a gold plating process, and finally the dry film is removed. Figure 9 As shown; S11, first protect the position of the second laminated copper foil 3.2 that needs to be retained with a dry film, and protect the first laminated copper foil 3.1 and the electroplated gold layer 5.1 as a whole with a dry film, then etch a circuit pattern on the second laminated copper foil 3.2, and finally remove the dry film; S12, firstly, the second pressed copper foil 3.2 on the outer side below the second connecting pillar 4.2 is protected with a dry film, and the first pressed copper foil 3.1 and the electroplated gold layer 5.1 are protected with a dry film, so that the second pressed copper foil 3.2 below the second connecting pillar 4.2 is exposed, and then a chemical gold plating layer 5.2 is formed on the second pressed copper foil 3.2 below the second connecting pillar 4.2 through a chemical gold plating process, and finally the dry film is removed, as shown in FIG. Figure 10 As shown; S13. Take the first prepreg 2.1, the second prepreg 2.2, the first pressed copper foil 3.1, and the second pressed copper foil 3.2, and stack and press the first pressed copper foil 3.1, the first prepreg 2.1, the semi-finished printed circuit board, the second prepreg 2.2, and the second pressed copper foil 3.2 together in order from top to bottom. S14. Laser drilling is performed to form a first communication hole between the uppermost first pressed copper foil 3.1 and the first prepreg 2.1, thereby exposing a portion of the upper surface of the first pressed copper foil 3.1 below the uppermost first prepreg 2.1. Laser drilling is performed to form a second communication hole between the lowermost second pressed copper foil 3.2 and the second prepreg 2.2, thereby exposing a portion of the lower surface of the second pressed copper foil 3.2 above the lowermost second prepreg 2.2. S15. Copper is filled in the first and second communicating holes through an electroplating filling process to form first communicating pillars 4.1 and second communicating pillars 4.2. The first communicating pillars 4.1 electrically connect the two uppermost layers of the first pressed copper foil 3.1, and the second communicating pillars 4.2 electrically connect the two lowermost layers of the second pressed copper foil 3.2. S16, first protecting the position of the first laminated copper foil 3.1 that needs to be retained with a dry film, and protecting the entire second laminated copper foil 3.2 with a dry film, then etching a circuit pattern on the first laminated copper foil 3.1, and finally removing the dry film; S17. Protect the first pressed copper foil 3.1 above the first connecting pillar 4.1 with a dry film, and protect the entire second pressed copper foil 3.2 with a dry film, exposing the first pressed copper foil 3.1 above the first connecting pillar 4.1. Then, form an electroplated gold layer 5.1 on the first pressed copper foil 3.1 above the first connecting pillar 4.1 through a gold electroplating process, and finally remove the dry film. S18, first protecting the portion of the second laminated copper foil 3.2 that needs to be retained with a dry film, then protecting the entire first laminated copper foil 3.1 and the electroplated gold layer 5.1 with a dry film, then etching a circuit pattern on the second laminated copper foil 3.2, and finally removing the dry film; S19. First, the second pressed copper foil 3.2 on the outer side below the second connecting pillar 4.2 is protected with a dry film, and the first pressed copper foil 3.1 and the electroplated gold layer 5.1 are protected with a dry film, so that the second pressed copper foil 3.2 below the second connecting pillar 4.2 is exposed. Then, a chemical gold plating process is performed to form a chemical gold plating layer 5.2 on the second pressed copper foil 3.2 below the second connecting pillar 4.2. Finally, the dry film is removed. S20, repeating steps S13 to S19 for a specified number of times as required; S21, obtain the finished printed circuit board, such as Figure 11 shown.

[0040] Example 2 A printed circuit board without lead electroplating gold and gold, such as Figure 22 As shown, it includes a substrate assembly, a first prepreg 2.1, a second prepreg 2.2, a first pressed copper foil 3.1, a second pressed copper foil 3.2, a first connecting column 4.1, a second connecting column 4.2, an electroplated gold layer 5.1 and a chemically plated gold layer 5.2. The substrate assembly includes at least two substrates 1, and two adjacent substrates 1 are connected by a third prepreg 2.3. The substrate 1 includes an epoxy resin substrate 1.1, an upper substrate copper foil 1.2 located on the upper surface of the epoxy resin substrate 1.1, and a lower substrate copper foil 1.3 located on the lower surface of the epoxy resin substrate 1.1. A through hole is formed on the substrate assembly, and a copper layer 1.4 is formed on the inner wall of the through hole. The copper layer 1.4 electrically connects all the upper copper foils 1.2 of the substrate with all the lower copper foils 1.3 of the substrate. A resin column 1.5 is formed in the copper layer 1.4. Several layers of first prepregs 2.1 are provided above the substrate assembly. A first laminated copper foil 3.1 is provided on the upper surface of each first prepreg 2.1. Circuit patterns are provided on the first laminated copper foil 3.1 and the upper copper foil 1.2 of the substrate. First communication holes are provided in the first prepregs 2.1 and the upper laminated copper foil 3.1. First communication posts 4.1 are provided within the first communication holes. An electroplated gold layer 5.1 is provided on the upper surface of each first communication post 4.1. Adjacent electroplated gold layers 5.1, as well as between the bottom electroplated gold layer 5.1 and the upper copper foil 1.2 of the substrate, are electrically connected via the first communication posts 4.1. Several layers of second prepregs 2.2 are provided beneath the substrate 1. A layer of second laminated copper foil 3.2 is provided on the lower surface of each layer of second prepreg 2.2. Circuit patterns are provided on the second laminated copper foil 3.2 and the substrate's lower copper foil 1.3. Second communication holes are provided in the second prepregs 2.2 and the underlying second laminated copper foil 3.2. Second communication posts 4.2 are provided within the second communication holes. A chemically plated gold layer 5.2 is provided on the lower surface of each second communication post 4.2. Adjacent chemically plated gold layers 5.2, as well as between the uppermost chemically plated gold layer 5.2 and the lowermost substrate's lower copper foil 1.3, are electrically connected via the second communication posts 4.2.

[0041] The method for manufacturing the above-mentioned leadless gold-plated and gold-plated printed circuit board comprises the following steps: S1. Provide a substrate assembly, comprising at least two layers of substrates 1, wherein two adjacent layers of substrates 1 are connected via a third prepreg 2.3, wherein the substrate 1 comprises an epoxy resin substrate 1.1, an upper copper foil 1.2 located on the upper surface of the epoxy resin substrate 1.1, and a lower copper foil 1.3 located on the lower surface of the epoxy resin substrate 1.1. The upper copper foil 1.2 located on the top and the lower copper foil 1.3 located on the bottom have not been etched with a circuit pattern, while the remaining upper copper foils 1.2 and lower copper foils 1.3 have been pre-etched with circuit patterns, such as Figure 12 As shown; S2, drilling through holes on the substrate assembly through a mechanical drilling process, such as Figure 13 As shown; S3, copper is plated on the front, back, side and inner wall of the through hole of the substrate assembly through the copper electroplating process, so that the upper copper foil 1.2 of the substrate at the top and the lower copper foil 1.3 of the substrate at the bottom become thicker, and at the same time, a hole copper layer 1.4 is formed on the inner wall of the through hole, and the hole copper layer 1.4 electrically connects all the upper copper foils 1.2 of the substrate and all the lower copper foils 1.3 of the substrate. Figure 14 As shown; S4, forming a resin column 1.5 in the hole copper layer 1.4 through the resin plugging process, such as Figure 15 As shown; S5. Copper is plated on the front, back, and side surfaces of the substrate 1 through a copper electroplating process to make the upper copper foil 1.2 and the lower copper foil 1.3 thicker. The upper copper foil 1.2 covers the upper end surface of the resin column 1.5, and the lower copper foil 1.3 covers the lower end surface of the resin column 1.5. A circuit pattern is etched on the upper copper foil 1.2 located at the top and the lower copper foil 1.3 located at the bottom. Figure 16 As shown; S6. Take the first prepreg 2.1, the second prepreg 2.2, the first pressed copper foil 3.1 and the second pressed copper foil 3.2, and stack and press the first pressed copper foil 3.1, the first prepreg 2.1, the substrate assembly, the second prepreg 2.2 and the second pressed copper foil 3.2 together in order from top to bottom to form a semi-finished printed circuit board, such as Figure 17 As shown; S7. A first connecting hole is formed on the first pressed copper foil 3.1 and the first prepreg 2.1 by laser drilling, so that the upper surface of the upper copper foil 1.2 of the substrate within the upper end surface of the resin column 1.5 is exposed. A second connecting hole is formed on the second pressed copper foil 3.2 and the second prepreg 2.2 by laser drilling, so that the lower surface of the lower copper foil 1.3 of the substrate within the lower end surface of the resin column 1.5 is exposed. Figure 18 As shown; S8, copper is filled in the first and second connecting holes by electroplating filling process to form first connecting pillars 4.1 and second connecting pillars 4.2. The first connecting pillars 4.1 electrically connect the first pressed copper foil 3.1 and the upper copper foil 1.2 of the substrate, and the second connecting pillars 4.2 electrically connect the second pressed copper foil 3.2 and the lower copper foil 1.3 of the substrate. Figure 19 As shown; S9, first protecting the position of the first laminated copper foil 3.1 that needs to be retained with a dry film, and protecting the entire second laminated copper foil 3.2 with a dry film, then etching a circuit pattern on the first laminated copper foil 3.1, and finally removing the dry film; S10, firstly, the first pressed copper foil 3.1 above the first connecting pillar 4.1 is protected with a dry film, and the second pressed copper foil 3.2 is protected with a dry film, so that the first pressed copper foil 3.1 above the first connecting pillar 4.1 is exposed, and then a gold plating layer 5.1 is formed on the first pressed copper foil 3.1 above the first connecting pillar 4.1 through a gold plating process, and finally the dry film is removed. Figure 20 As shown; S11, first protect the position of the second laminated copper foil 3.2 that needs to be retained with a dry film, and protect the first laminated copper foil 3.1 and the electroplated gold layer 5.1 as a whole with a dry film, then etch a circuit pattern on the second laminated copper foil 3.2, and finally remove the dry film; S12, firstly, the second pressed copper foil 3.2 on the outer side below the second connecting pillar 4.2 is protected with a dry film, and the first pressed copper foil 3.1 and the electroplated gold layer 5.1 are protected with a dry film, so that the second pressed copper foil 3.2 below the second connecting pillar 4.2 is exposed, and then a chemical gold plating layer 5.2 is formed on the second pressed copper foil 3.2 below the second connecting pillar 4.2 through a chemical gold plating process, and finally the dry film is removed, as shown in FIG. Figure 21 As shown; S13. Take the first prepreg 2.1, the second prepreg 2.2, the first pressed copper foil 3.1, and the second pressed copper foil 3.2, and stack and press the first pressed copper foil 3.1, the first prepreg 2.1, the semi-finished printed circuit board, the second prepreg 2.2, and the second pressed copper foil 3.2 together in order from top to bottom. S14. Laser drilling is performed to form a first communication hole between the uppermost first pressed copper foil 3.1 and the first prepreg 2.1, thereby exposing a portion of the upper surface of the first pressed copper foil 3.1 below the uppermost first prepreg 2.1. Laser drilling is performed to form a second communication hole between the lowermost second pressed copper foil 3.2 and the second prepreg 2.2, thereby exposing a portion of the lower surface of the second pressed copper foil 3.2 above the lowermost second prepreg 2.2. S15. Copper is filled in the first and second communicating holes through an electroplating filling process to form first communicating pillars 4.1 and second communicating pillars 4.2. The first communicating pillars 4.1 electrically connect the two uppermost layers of the first pressed copper foil 3.1, and the second communicating pillars 4.2 electrically connect the two lowermost layers of the second pressed copper foil 3.2. S16, first protecting the position of the first laminated copper foil 3.1 that needs to be retained with a dry film, and protecting the entire second laminated copper foil 3.2 with a dry film, then etching a circuit pattern on the first laminated copper foil 3.1, and finally removing the dry film; S17. Protect the first pressed copper foil 3.1 above the first connecting pillar 4.1 with a dry film, and protect the entire second pressed copper foil 3.2 with a dry film, exposing the first pressed copper foil 3.1 above the first connecting pillar 4.1. Then, form an electroplated gold layer 5.1 on the first pressed copper foil 3.1 above the first connecting pillar 4.1 through a gold electroplating process, and finally remove the dry film. S18, first protecting the portion of the second laminated copper foil 3.2 that needs to be retained with a dry film, then protecting the entire first laminated copper foil 3.1 and the electroplated gold layer 5.1 with a dry film, then etching a circuit pattern on the second laminated copper foil 3.2, and finally removing the dry film; S19. First, the second pressed copper foil 3.2 on the outer side below the second connecting pillar 4.2 is protected with a dry film, and the first pressed copper foil 3.1 and the electroplated gold layer 5.1 are protected with a dry film, so that the second pressed copper foil 3.2 below the second connecting pillar 4.2 is exposed. Then, a chemical gold plating process is performed to form a chemical gold plating layer 5.2 on the second pressed copper foil 3.2 below the second connecting pillar 4.2. Finally, the dry film is removed. S20, repeating steps S13 to S19 for a specified number of times as required; S21, obtain the finished printed circuit board, such as Figure 22 shown.

[0042] In Example 1 and Example 2, the thickness of the epoxy resin substrate 1.1 is 20.3-304.8 micrometers, and the thickness of the upper copper foil 1.2 and the lower copper foil 1.3 of the substrate are both 12-210 micrometers.

[0043] In Example 1 and Example 2, the thickness of the first prepreg 2.1 and the second prepreg 2.2 are both 35-304.8 μm.

[0044] In Example 2, the thickness of the third prepreg 2.3 is 35-304.8 μm.

[0045] In Example 1 and Example 2, the thickness of the first laminated copper foil 3.1 and the second laminated copper foil 3.2 are both 12-210 microns.

[0046] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A leadless gold-plated and chemically plated printed circuit board, comprising a substrate (1), a first prepreg (2.1), a second prepreg (2.2), a first pressed copper foil (3.1), a second pressed copper foil (3.2), a first connecting column (4.1), a second connecting column (4.2), an electroplated gold layer (5.1), and a chemically plated gold layer (5.2), wherein the substrate (1) comprises an epoxy resin substrate (1.1), an upper copper foil (1.2) located on the upper surface of the epoxy resin substrate (1.1), and a lower copper foil (1.3) located on the lower surface of the epoxy resin substrate (1.1); Its characteristics are: A through hole is provided on the substrate (1), a copper hole layer (1.4) is provided on the inner wall of the through hole, the copper hole layer (1.4) electrically connects the upper copper foil (1.2) of the substrate with the lower copper foil (1.3) of the substrate, and a resin column (1.5) is provided in the copper hole layer (1.4); A plurality of first prepreg sheets (2.1) are provided above a substrate (1); a first pressed copper foil (3.1) is provided on the upper surface of each first prepreg sheet (2.1); a circuit pattern is provided on the first pressed copper foil (3.1) and the upper copper foil (1.2) of the substrate; a first connecting hole is provided on the first prepreg sheet (2.1) and the first pressed copper foil (3.1) located above the first prepreg sheet; a first connecting column (4.1) is provided in the first connecting hole; and an electroplated gold layer ( 5.1), adjacent electroplated gold layers (5.1) and the bottom electroplated gold layer (5.1) and the upper copper foil (1.2) of the substrate are electrically connected via the first connecting column (4.1); A plurality of layers of second semi-cured sheets (2.2) are provided below the substrate (1); a layer of second pressed copper foil (3.2) is provided on the lower surface of each layer of the second semi-cured sheet (2.2); a circuit pattern is provided on the second pressed copper foil (3.2) and the substrate lower copper foil (1.3); a second connecting hole is provided on the second semi-cured sheet (2.2) and the second pressed copper foil (3.2) located therebelow; a second connecting column (4.2) is provided in the second connecting hole; a chemically plated gold layer (5.2) is provided on the lower surface of each second connecting column (4.2); adjacent chemically plated gold layers (5.2) and the uppermost chemically plated gold layer (5.2) and the substrate lower copper foil (1.3) are electrically connected via the second connecting column (4.2).

2. A leadless gold-plated and chemically plated printed circuit board, comprising a substrate assembly, a first prepreg (2.1), a second prepreg (2.2), a first pressed copper foil (3.1), a second pressed copper foil (3.2), a first connecting column (4.1), a second connecting column (4.2), an electroplated gold layer (5.1), and a chemically plated gold layer (5.2), wherein the substrate assembly comprises at least two layers of substrates (1), two adjacent layers of substrates (1) being connected via a third prepreg (2.3), and the substrate (1) comprises an epoxy resin substrate (1.1), an upper copper foil (1.2) located on the upper surface of the epoxy resin substrate (1.1), and a lower copper foil (1.3) located on the lower surface of the epoxy resin substrate (1.1); Its characteristics are: A through hole is provided on the substrate assembly, and a copper hole layer (1.4) is provided on the inner wall of the through hole. The copper hole layer (1.4) electrically connects all the copper foils (1.2) on the upper layer of the substrate with all the copper foils (1.3) on the lower layer of the substrate. A resin column (1.5) is provided in the copper hole layer (1.4). A plurality of first prepreg sheets (2.1) are provided above the substrate assembly, a first pressed copper foil (3.1) is provided on the upper surface of each first prepreg sheet (2.1), a circuit pattern is provided on the first pressed copper foil (3.1) and the upper copper foil (1.2) of the substrate, a first connecting hole is provided on the first prepreg sheet (2.1) and the first pressed copper foil (3.1) located thereon, a first connecting column (4.1) is provided in the first connecting hole, and an electroplated gold layer ( 5.1), adjacent electroplated gold layers (5.1) and the bottom electroplated gold layer (5.1) and the top copper foil (1.2) of the substrate are electrically connected via the first connecting column (4.1); A plurality of layers of second semi-cured sheets (2.2) are provided below the substrate (1); a layer of second pressed copper foil (3.2) is provided on the lower surface of each layer of the second semi-cured sheet (2.2); a circuit pattern is provided on the second pressed copper foil (3.2) and the substrate lower copper foil (1.3); a second connecting hole is provided on the second semi-cured sheet (2.2) and the second pressed copper foil (3.2) located therebelow; a second connecting column (4.2) is provided in the second connecting hole; a chemically plated gold layer (5.2) is provided on the lower surface of each second connecting column (4.2); adjacent chemically plated gold layers (5.2) and the uppermost chemically plated gold layer (5.2) and the lowermost substrate copper foil (1.3) are electrically connected via the second connecting column (4.2).

3. The method for manufacturing a leadless gold-plated and gold-plated printed circuit board according to claim 1, wherein The manufacturing method comprises the following steps: S1. Providing a substrate (1), the substrate (1) comprising an epoxy resin substrate (1.1), an upper copper foil (1.2) located on the upper surface of the epoxy resin substrate (1.1), and a lower copper foil (1.3) located on the lower surface of the epoxy resin substrate (1.1); S2, drilling a through hole on the substrate (1) by a mechanical drilling process; S3, copper plating is performed on the front, back, side and inner wall of the through hole of the substrate (1) through a copper electroplating process, so that the upper copper foil (1.2) and the lower copper foil (1.3) of the substrate become thicker, and at the same time, a hole copper layer (1.4) is formed on the inner wall of the through hole, and the hole copper layer (1.4) electrically connects the upper copper foil (1.2) and the lower copper foil (1.3) of the substrate; S4, forming a resin column (1.5) in the hole copper layer (1.4) through a resin plugging process; S5. Copper is plated on the front, back and side surfaces of the substrate (1) through a copper electroplating process to thicken the upper copper foil (1.2) and the lower copper foil (1.3) of the substrate. The upper copper foil (1.2) of the substrate covers the upper end surface of the resin column (1.5), and the lower copper foil (1.3) of the substrate covers the lower end surface of the resin column (1.5). A circuit pattern is etched on the upper copper foil (1.2) and the lower copper foil (1.3); S6. Take the first prepreg (2.1), the second prepreg (2.2), the first pressed copper foil (3.1) and the second pressed copper foil (3.2), and stack and press the first pressed copper foil (3.1), the first prepreg (2.1), the substrate (1), the second prepreg (2.2) and the second pressed copper foil (3.2) together in a top-down order to form a semi-finished printed circuit board; S7. Processing a first connecting hole on the first pressed copper foil (3.1) and the first prepreg (2.1) by a laser drilling process, so that the upper surface of the upper copper foil (1.2) of the substrate within the upper end surface of a portion of the resin column (1.5) is exposed; processing a second connecting hole on the second pressed copper foil (3.2) and the second prepreg (2.2) by a laser drilling process, so that the lower surface of the lower copper foil (1.3) of the substrate within the lower end surface of a portion of the resin column (1.5) is exposed; S8. Filling copper in the first connecting hole and the second connecting hole through an electroplating filling process to form a first connecting column (4.1) and a second connecting column (4.2), wherein the first connecting column (4.1) electrically connects the first pressed copper foil (3.1) and the upper copper foil (1.2) of the substrate, and the second connecting column (4.2) electrically connects the second pressed copper foil (3.2) and the lower copper foil (1.3) of the substrate; S9, firstly protecting the position of the first laminated copper foil (3.1) that needs to be retained with a dry film, and protecting the entire second laminated copper foil (3.2) with a dry film, then etching a circuit pattern on the first laminated copper foil (3.1), and finally removing the dry film; S10, firstly protecting the first pressed copper foil (3.1) on the outer side above the first connecting column (4.1) with a dry film, and protecting the entire second pressed copper foil (3.2) with a dry film, so that the first pressed copper foil (3.1) above the first connecting column (4.1) is exposed, and then forming an electroplated gold layer (5.1) on the first pressed copper foil (3.1) above the first connecting column (4.1) through a gold electroplating process, and finally removing the dry film; S11, firstly protecting the position of the second laminated copper foil (3.2) that needs to be retained with a dry film, and protecting the first laminated copper foil (3.1) and the electroplated gold layer (5.1) as a whole with a dry film, then etching a circuit pattern on the second laminated copper foil (3.2), and finally removing the dry film; S12, first protecting the second pressed copper foil (3.2) on the outer side below the second connecting column (4.2) with a dry film, and protecting the first pressed copper foil (3.1) and the electroplated gold layer (5.1) as a whole with a dry film, so that the second pressed copper foil (3.2) below the second connecting column (4.2) is exposed, and then forming a chemical gold plating layer (5.2) on the second pressed copper foil (3.2) below the second connecting column (4.2) through a chemical gold plating process, and finally removing the dry film; S13, taking the first prepreg (2.1), the second prepreg (2.2), the first pressed copper foil (3.1) and the second pressed copper foil (3.2), and stacking and pressing the first pressed copper foil (3.1), the first prepreg (2.1), the semi-finished printed circuit board, the second prepreg (2.2) and the second pressed copper foil (3.2) together in order from top to bottom; S14, machining a first connecting hole on the first pressed copper foil (3.1) and the first prepreg (2.1) located at the top through a laser drilling process, so that a portion of the upper surface of the first pressed copper foil (3.1) located below the first prepreg (2.1) located at the top is exposed, and machining a second connecting hole on the second pressed copper foil (3.2) and the second prepreg (2.2) located at the bottom through a laser drilling process, so that a portion of the lower surface of the second pressed copper foil (3.2) located above the second prepreg (2.2) located at the bottom is exposed; S15, copper is filled in the first connecting hole and the second connecting hole through an electroplating filling process to form a first connecting column (4.1) and a second connecting column (4.2), so that the two layers of the first pressed copper foil (3.1) at the top are electrically connected through the first connecting column (4.1), and the two layers of the second pressed copper foil (3.2) at the bottom are electrically connected through the second connecting column (4.2); S16, first protecting the position of the first laminated copper foil (3.1) that needs to be retained with a dry film, protecting the entire second laminated copper foil (3.2) with a dry film, then etching a circuit pattern on the first laminated copper foil (3.1), and finally removing the dry film; S17, firstly protecting the first pressed copper foil (3.1) on the outer side above the first connecting column (4.1) with a dry film, and protecting the entire second pressed copper foil (3.2) with a dry film, so that the first pressed copper foil (3.1) above the first connecting column (4.1) is exposed, and then forming an electroplated gold layer (5.1) on the first pressed copper foil (3.1) above the first connecting column (4.1) through a gold electroplating process, and finally removing the dry film; S18, first protecting the position of the second laminated copper foil (3.2) that needs to be retained with a dry film, protecting the first laminated copper foil (3.1) and the electroplated gold layer (5.1) as a whole with a dry film, then etching a circuit pattern on the second laminated copper foil (3.2), and finally removing the dry film; S19, first protecting the second pressed copper foil (3.2) on the outer side below the second connecting column (4.2) with a dry film, and protecting the first pressed copper foil (3.1) and the electroplated gold layer (5.1) as a whole with a dry film, so that the second pressed copper foil (3.2) below the second connecting column (4.2) is exposed, and then forming a chemical gold plating layer (5.2) on the second pressed copper foil (3.2) below the second connecting column (4.2) through a chemical gold plating process, and finally removing the dry film; S20, repeating steps S13 to S19 for a specified number of times as required; S21, obtaining a finished printed circuit board.

4. The method for manufacturing a leadless gold-plated and gold-plated printed circuit board according to claim 2, wherein The manufacturing method comprises the following steps: S1. Provide a substrate assembly, the substrate assembly comprising at least two layers of substrates (1), two adjacent layers of substrates (1) being connected via a third semi-cured sheet (2.3), the substrate (1) comprising an epoxy resin substrate (1.1), an upper layer of substrate copper foil (1.2) located on the upper surface of the epoxy resin substrate (1.1), and a lower layer of substrate copper foil (1.3) located on the lower surface of the epoxy resin substrate (1.1), the uppermost layer of substrate copper foil (1.2) and the lowermost layer of substrate copper foil (1.3) being not etched with circuit patterns, and the remaining layers of substrate copper foil (1.2) and substrate lower layer copper foil (1.3) being pre-etched with circuit patterns; S2, drilling a through hole on the substrate assembly by a mechanical drilling process; S3. Copper is plated on the front, back, side and inner wall of the through hole of the substrate assembly through a copper electroplating process, so that the upper copper foil (1.2) of the substrate at the top and the lower copper foil (1.3) of the substrate at the bottom become thicker, and at the same time, a hole copper layer (1.4) is formed on the inner wall of the through hole, and the hole copper layer (1.4) electrically connects all the upper copper foils (1.2) of the substrate and all the lower copper foils (1.3) of the substrate; S4, forming a resin column (1.5) in the hole copper layer (1.4) through a resin plugging process; S5. Copper is plated on the front, back and side surfaces of the substrate (1) through a copper electroplating process to thicken the upper copper foil (1.2) and the lower copper foil (1.3) of the substrate. The upper copper foil (1.2) of the substrate covers the upper end surface of the resin column (1.5), and the lower copper foil (1.3) of the substrate covers the lower end surface of the resin column (1.5). A circuit pattern is etched on the upper copper foil (1.2) of the substrate located at the top and the lower copper foil (1.3) of the substrate located at the bottom. S6. Take the first prepreg (2.1), the second prepreg (2.2), the first pressed copper foil (3.1) and the second pressed copper foil (3.2), and stack and press the first pressed copper foil (3.1), the first prepreg (2.1), the substrate assembly, the second prepreg (2.2) and the second pressed copper foil (3.2) together in a top-down order to form a semi-finished printed circuit board; S7. Processing a first connecting hole on the first pressed copper foil (3.1) and the first prepreg (2.1) by a laser drilling process, so that the upper surface of the upper copper foil (1.2) of the substrate within the upper end surface of a portion of the resin column (1.5) is exposed; processing a second connecting hole on the second pressed copper foil (3.2) and the second prepreg (2.2) by a laser drilling process, so that the lower surface of the lower copper foil (1.3) of the substrate within the lower end surface of a portion of the resin column (1.5) is exposed; S8. Filling copper in the first connecting hole and the second connecting hole through an electroplating filling process to form a first connecting column (4.1) and a second connecting column (4.2), wherein the first connecting column (4.1) electrically connects the first pressed copper foil (3.1) and the upper copper foil (1.2) of the substrate, and the second connecting column (4.2) electrically connects the second pressed copper foil (3.2) and the lower copper foil (1.3) of the substrate; S9, firstly protecting the position of the first laminated copper foil (3.1) that needs to be retained with a dry film, and protecting the entire second laminated copper foil (3.2) with a dry film, then etching a circuit pattern on the first laminated copper foil (3.1), and finally removing the dry film; S10, firstly protecting the first pressed copper foil (3.1) on the outer side above the first connecting column (4.1) with a dry film, and protecting the entire second pressed copper foil (3.2) with a dry film, so that the first pressed copper foil (3.1) above the first connecting column (4.1) is exposed, and then forming an electroplated gold layer (5.1) on the first pressed copper foil (3.1) above the first connecting column (4.1) through a gold electroplating process, and finally removing the dry film; S11, firstly protecting the position of the second laminated copper foil (3.2) that needs to be retained with a dry film, and protecting the first laminated copper foil (3.1) and the electroplated gold layer (5.1) as a whole with a dry film, then etching a circuit pattern on the second laminated copper foil (3.2), and finally removing the dry film; S12, first protecting the second pressed copper foil (3.2) on the outer side below the second connecting column (4.2) with a dry film, and protecting the first pressed copper foil (3.1) and the electroplated gold layer (5.1) as a whole with a dry film, so that the second pressed copper foil (3.2) below the second connecting column (4.2) is exposed, and then forming a chemical gold plating layer (5.2) on the second pressed copper foil (3.2) below the second connecting column (4.2) through a chemical gold plating process, and finally removing the dry film; S13, taking the first prepreg (2.1), the second prepreg (2.2), the first pressed copper foil (3.1) and the second pressed copper foil (3.2), and stacking and pressing the first pressed copper foil (3.1), the first prepreg (2.1), the semi-finished printed circuit board, the second prepreg (2.2) and the second pressed copper foil (3.2) together in order from top to bottom; S14, machining a first connecting hole on the first pressed copper foil (3.1) and the first prepreg (2.1) located at the top through a laser drilling process, so that a portion of the upper surface of the first pressed copper foil (3.1) located below the first prepreg (2.1) located at the top is exposed, and machining a second connecting hole on the second pressed copper foil (3.2) and the second prepreg (2.2) located at the bottom through a laser drilling process, so that a portion of the lower surface of the second pressed copper foil (3.2) located above the second prepreg (2.2) located at the bottom is exposed; S15, copper is filled in the first connecting hole and the second connecting hole through an electroplating filling process to form a first connecting column (4.1) and a second connecting column (4.2), so that the two layers of the first pressed copper foil (3.1) at the top are electrically connected through the first connecting column (4.1), and the two layers of the second pressed copper foil (3.2) at the bottom are electrically connected through the second connecting column (4.2); S16, first protecting the position of the first laminated copper foil (3.1) that needs to be retained with a dry film, protecting the entire second laminated copper foil (3.2) with a dry film, then etching a circuit pattern on the first laminated copper foil (3.1), and finally removing the dry film; S17, firstly protecting the first pressed copper foil (3.1) on the outer side above the first connecting column (4.1) with a dry film, and protecting the entire second pressed copper foil (3.2) with a dry film, so that the first pressed copper foil (3.1) above the first connecting column (4.1) is exposed, and then forming an electroplated gold layer (5.1) on the first pressed copper foil (3.1) above the first connecting column (4.1) through a gold electroplating process, and finally removing the dry film; S18, first protecting the position of the second laminated copper foil (3.2) that needs to be retained with a dry film, protecting the first laminated copper foil (3.1) and the electroplated gold layer (5.1) as a whole with a dry film, then etching a circuit pattern on the second laminated copper foil (3.2), and finally removing the dry film; S19, first protecting the second pressed copper foil (3.2) on the outer side below the second connecting column (4.2) with a dry film, and protecting the first pressed copper foil (3.1) and the electroplated gold layer (5.1) as a whole with a dry film, so that the second pressed copper foil (3.2) below the second connecting column (4.2) is exposed, and then forming a chemical gold plating layer (5.2) on the second pressed copper foil (3.2) below the second connecting column (4.2) through a chemical gold plating process, and finally removing the dry film; S20, repeating steps S13 to S19 for a specified number of times as required; S21, obtaining a finished printed circuit board.

5. The method for manufacturing a leadless gold-plated and gold-plated printed circuit board according to claim 3 or 4, wherein: The thickness of the epoxy resin substrate (1.1) is 20.3-304.8 micrometers, and the thickness of the upper copper foil (1.2) and the lower copper foil (1.3) of the substrate are both 12-210 micrometers.

6. The method for manufacturing a leadless gold-plated and gold-plated printed circuit board according to claim 3 or 4, wherein: The thickness of the first prepreg (2.1) and the second prepreg (2.2) are both 35-304.8 microns.

7. The method for manufacturing a leadless gold-plated and gold-plated printed circuit board according to claim 4, wherein: The thickness of the third prepreg (2.3) is 35-304.8 microns.

8. The method for manufacturing a leadless gold-plated and gold-plated printed circuit board according to claim 3 or 4, wherein: The thickness of the first pressed copper foil (3.1) and the second pressed copper foil (3.2) are both 12-210 micrometers.

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