Manufacturing method of ultra-thick copper gold plating plate

Abstract

The invention discloses a method for manufacturing an ultra-thick copper gold plating plate, which comprises the following steps of: electroplating: cutting a copper plate according to a specified size, and electroplating thick copper on the whole plate; a circuit manufacturing step: cutting a circuit pattern on the copper plate, and reserving a connecting position to ensure that the independent bonding pad and the circuit do not fall off; a first pressing step: pressing the copper foil with the adhesive layer on one side and the copper plate, and filling the adhesive between the circuits; in the etching step, after the thick copper surface is covered with a dry film, the laminated thin copper on the whole surface is removed through acid etching; a groove milling step: cutting off the reserved connection position, so that the bonding pad and the circuit are isolated from the large copper surface and are not short-circuited; and a second lamination step: laminating the copper plates and the corresponding number of glue layers, filling the connection positions with glue, and carrying out a final forming process. According to the invention, the problem that the super-thick copper gold plating plate in the prior art is too large in side erosion of a gold plating bonding pad, the appearance is easily affected, and the quality problem is caused by a large height difference between a base material surface and a copper surface is solved.

Description

Technical Field

[0001] The invention relates to the field of PCB processing and manufacturing, and in particular to a method for manufacturing an ultra-thick copper-gold plate. Background Art

[0002] In the field of PCB processing and manufacturing, electroplated gold plates are very common, usually probe pads or plug-in pads (gold fingers). Gold fingers can be made by pulling leads, while probe pads are independent pads and cannot be made by pulling leads, because lead etching will cause irregular pads or lead residues (some dense electroplated gold pads cannot pull leads). Therefore, conventional independent pad electroplated gold plates are all made by electroplating the back cover dry film electroplated gold, and then made by alkaline etching. Gold is alkali-resistant and electroplated gold is used as corrosion resistance. This practice means that the electroplated gold pads will have a certain amount of side corrosion. In addition, at present, ultra-thick copper electroplated gold plates can neither pull electroplated gold leads nor be made by electroplating, electroplating, and then alkaline etching, because the side corrosion depth of alkaline etching is related to the thickness of copper. The thicker the copper, the greater the side corrosion. Excessive side corrosion will cause the edge of the electroplated gold pad to collapse or the gold layer to break, which not only affects the appearance, but also may cause small quality risks of the pad.

[0003] In view of this, the present technical scheme proposes a method for manufacturing an ultra-thick copper-gold plate, that is, first making a circuit pattern, and then electroplating a layer of copper on the entire board surface, using the plated thin copper layer as a lead, and then electroplating and alkaline etching. Because the circuit pattern has been made before electroplating, alkaline etching only etches the plated thin copper layer, and the side corrosion is extremely small, which effectively reduces the occurrence of edge collapse of the electroplated gold pad or breakage of the gold layer, does not affect the appearance, and reduces the risk of the pad being too small. Summary of the invention

[0004] The technical solution of the present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the main purpose of the present invention is to provide a method for manufacturing an ultra-thick copper-gold plate, which aims to solve the quality problems of the ultra-thick copper-gold plate in the prior art, such as excessive side etching of the gold pad, which easily affects the appearance, and a large height difference between the substrate surface and the copper surface.

[0005] To achieve the above object, the present invention provides a method for manufacturing an ultra-thick copper electroplated gold plate, comprising an electroplating step, cutting the copper plate into a specified size, and then electroplating the entire plate with thick copper; Circuit production steps: cut the circuit pattern on the copper plate and leave connection positions to ensure that independent pads and circuits do not fall off; In the first lamination step, a copper foil with an adhesive layer on one side is pressed with a copper plate so that the adhesive fills between each circuit; In the etching step, after the thick copper surface is covered with dry film, the entire surface of the pressed thin copper is removed by acid etching; In the grooving step, the reserved connection positions are disconnected to isolate the pads and circuits from the large copper surface without short circuit; In the second pressing step, each copper plate and a corresponding number of adhesive layers are stacked and pressed together to fill the connection positions with glue and undergo a final molding process.

[0006] As a further solution of the present invention, the molding process after the second pressing step includes: Grind the board to remove the glue overflowing from the circuits on both sides of the circuit board; Drilling: Drill holes on the circuit board to connect the circuits of each layer, and perform burr treatment on the hole positions; Copper deposition, using chemical copper deposition, deposits copper on the surface of the circuit board and in the holes to form conduction; Alkaline etching uses alkaline etching solution to etch away a layer of thin electroplated copper on the unprotected spacers on the board surface.

[0007] As a further solution of the present invention, after the copper deposition step, the hole copper and the surface copper are electroplated to be thickened on the basis of the copper deposition.

[0008] As a further solution of the present invention, after the alkaline etching step, an ink layer is printed on the surface of the circuit board.

[0009] As a further solution of the present invention, the molding process after the second pressing step further includes the following testing steps: Electrical testing: open and short circuit testing of circuit boards; Visual inspection: Check the appearance of the circuit board.

[0010] As a further solution of the present invention, after the electroplating thickening step, a dry film of equivalent size is attached to the circuit board surface, and the pads that need to be electroplated are exposed through exposure and development, and then a gold layer is electroplated on the exposed pads, and the film is stripped, and then the dry film is attached to the entire board, and the circuit spacing and electroplated gold pads are exposed through exposure and development.

[0011] As a further solution of the present invention, after the ink layer is printed, the electro-gold area is firstly covered with blue glue, and then a thin gold layer is plated on the circuit pattern.

[0012] As a further solution of the present invention, a ceramic grinding plate is used to grind away the overflowed glue.

[0013] As a further solution of the present invention, the circuit production step uses laser cutting to form a circuit pattern.

[0014] As a further solution of the present invention, the adhesive layer is a polypropylene adhesive layer.

[0015] The beneficial effects of the present invention are as follows: The method for manufacturing an ultra-thick copper electroplated gold plate proposed by the present invention comprises the following steps: firstly manufacturing a circuit pattern, and then electroplating a layer of copper on the entire board surface, using the electroplated thin copper layer as a lead, and then electroplating and alkaline etching. Since the circuit pattern has been prepared before electroplating, alkaline etching only etches the electroplated thin copper layer, and produces minimal side corrosion, effectively reducing the occurrence of edge collapse of the electroplated gold pad or fracture of the gold layer. Moreover, since the height difference between the substrate surface and the copper surface is reduced, the difficulty of solder mask manufacturing is reduced, the production efficiency is improved, and the product quality is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the technical solutions of the present invention or the technical solutions of the present invention in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the technical solutions of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0017] Figure 1 It is a flow chart of the main process steps of the present invention.

[0018] Figure 2 This is a partial display diagram of the actual object when the circuit pattern is cut out in the present invention.

[0019] Figure 3 This is a partial display diagram of the actual object after the various connecting positions are pressed together during the gong groove step in the present invention.

[0020] Figure 4 This is a partial view of the actual object after the etching step in the present invention.

[0021] Figure 5 This is a partial display diagram of the circuit board in the present invention after being printed with ink (green oil).

[0022] Figure 6 This is a physical display diagram of the finished product of the present invention. DETAILED DESCRIPTION

[0023] as follows: Please refer to the attached Figure 1-6 , The main implementation steps include electroplating steps, cutting the copper plate into the specified size, and then electroplating the whole plate with thick copper; (Before the electroplating step, the material needs to be cut, that is, the large-sized copper plate is cut into small plates that meet the size of the PCB working board, and then the entire plate is thickened with copper to make the copper thickness meet the processing requirements and reserve the copper thickness for loss in the subsequent process).

[0024] Circuit production steps: cut the circuit pattern on the copper plate and leave connection positions to ensure that independent pads and circuits do not fall off; (The overall idea is to first perform laser cutting to produce the circuit pattern, and then electroplate a layer of copper on the entire board surface, use the plated thin copper layer as the lead, and then electroplate gold and alkaline etching).

[0025] In the first lamination step, a copper foil with an adhesive layer on one side is pressed with a copper plate so that the adhesive fills between each circuit; (You can choose to use 3 sheets of high-glue PP and Hoz copper foil to press them into a sub-board, so that the PP glue can fill the circuit spacing. Use different layers and thicknesses of glue according to different board types and specifications. The glue layer can use a polypropylene glue layer).

[0026] In the etching step, after the thick copper surface is covered with dry film, the entire surface of the pressed thin copper is removed by acid etching; (Acid etching can be used, the dry film covers the thick copper surface, and acid etching is used to remove the entire surface of thin copper added by pressing).

[0027] In the grooving step, the reserved connection positions are disconnected to isolate the pads and circuits from the large copper surface without short circuit; (The connection positions reserved by laser cutting on the breaker board isolate the pad and the circuit from the large copper surface to prevent short circuit).

[0028] In the second pressing step, each copper plate and a corresponding number of adhesive layers are stacked and pressed together to fill the connection positions with glue and undergo a final molding process.

[0029] (For example, stack two sub-boards and a corresponding number of high-glue PP in sequence, fill the connection positions with glue and press them into a semi-finished PCB board with a thickness that meets the customer's requirements).

[0030] A preferred embodiment of the present invention: the molding process after the second pressing step includes: Grind the board to remove the glue overflowing from the circuits on both sides of the circuit board; (To grind off the PP glue overflowing from the circuits on both sides of the semi-finished PCB board, a ceramic grinding plate can be used).

[0031] Drilling: Drill holes on the circuit board to connect the circuits of each layer, and perform burr treatment on the hole positions; Copper deposition, using chemical copper deposition, deposits copper on the surface of the circuit board and in the holes to form conduction; Alkaline etching uses alkaline etching solution to etch away a layer of thin electroplated copper on the unprotected spacers on the board surface.

[0032] A preferred embodiment of the present invention is as follows: after the copper deposition step, the hole copper and the surface copper are electroplated and thickened on the basis of the copper deposition.

[0033] A preferred embodiment of the present invention is to print an ink layer on the surface of the circuit board after the alkaline etching step.

[0034] (A layer of ink is printed on the PCB surface to protect it.) After that, the required text and logo can be printed on the outer layer of the PCB.

[0035] A preferred embodiment of the present invention: the molding process after the second pressing step further includes the following testing steps: electrical testing, performing an open and short circuit test on the circuit board; and visual inspection, performing an appearance inspection on the circuit board.

[0036] A preferred embodiment of the present invention is as follows: after the electroplating thickening step, a dry film of a considerable size is attached to the circuit board surface, and the pads to be electroplated are exposed by exposure and development, and then a gold layer is electroplated on the exposed pads, and the film is stripped, and then the dry film is attached to the entire board, and the circuit spacing and electroplated gold pads are exposed by exposure and development.

[0037] A preferred embodiment of the present invention is as follows: after printing the ink layer, the electro-gold area is firstly covered with blue glue, and then a thin gold layer is plated on the circuit pattern.

[0038] (Before immersion gold, you can use blue glue to cover the electroplated gold area and plate a thin layer of gold on the circuit pattern to protect the circuit).

[0039] The above description is only a preferred embodiment of the technical solution of the present invention, and does not limit the patent scope of the technical solution of the present invention. All equivalent structural changes made by using the contents of the technical solution description and drawings of the present invention under the conception of the technical solution of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the technical solution of the present invention.

Claims

1. A method for making an ultra-thick copper electroplated gold plate, characterized in that: The steps include: S1, electroplating steps, After the copper plate is cut to the specified size, the whole plate is electroplated with thick copper; S2, circuit production steps, Cut the circuit pattern on the copper plate and leave connection positions to ensure that independent pads and circuits do not fall off; S3, the first pressing step, Use copper foil with adhesive layer on one side to press copper plate, so that the adhesive fills between each circuit; S4, etching step, After covering the thick copper surface with dry film, the entire surface of the pressed thin copper is removed by acid etching; S5, gong groove step, Cut off the reserved connection positions to isolate the pads and circuits from the large copper surface and prevent short circuits; S6, the second pressing step, The copper plates and the corresponding number of adhesive layers are stacked and pressed together, the connection positions are filled with glue, and then go through the final molding process.

2. The method for making an ultra-thick copper electroplated gold plate according to claim 1, characterized in that: The molding process after the second pressing step includes: S61, grinding plate, Grind off the glue overflowing from the circuits on both sides of the circuit board; S62, drilling, Drill holes on the circuit board to conduct the circuits of each layer, and perform burr treatment on the hole positions; S63, copper immersion, Chemical copper deposition is used to deposit copper on the surface of the circuit board and in the holes to form conduction; S64, alkaline etching, An alkaline etching solution is used to etch away a thin layer of electroplated copper on the unprotected spacers on the board surface.

3. The method for making the ultra-thick copper electroplated gold plate according to claim 2, characterized in that: After the copper deposition step, the hole copper and the surface copper are electroplated and thickened on the basis of the copper deposition.

4. The method for making an ultra-thick copper electroplated gold plate according to claim 2, characterized in that: After the alkaline etching step, an ink layer is printed on the surface of the circuit board.

5. The method for making an ultra-thick copper electroplated gold plate according to claim 2, characterized in that: The molding process after the second pressing step also includes the following testing steps: C1, electrical measurement, Conduct open and short circuit tests on the circuit board; C2. Visual inspection, Perform a visual inspection of the circuit board.

6. The method for making the ultra-thick copper electroplated gold plate according to claim 3, characterized in that: After the electroplating thickening step, a dry film of equivalent size is attached to the circuit board surface, and the pads that need to be electroplated are exposed through exposure and development. Then a gold layer is electroplated on the exposed pads and the film is stripped. Then the dry film is attached to the entire board, and the circuit spacing and electroplated gold pads are exposed through exposure and development.

7. The method for making an ultra-thick copper electroplated gold plate according to claim 4, characterized in that: After printing the ink layer, the electro-gold area is first covered with blue glue, and then a thin gold layer is plated on the circuit pattern.

8. The method for making an ultra-thick copper electroplated gold plate according to claim 2, characterized in that: Ceramic grinding plates are used to remove overflowed adhesive.

9. The method for making an ultra-thick copper-gold plate according to claim 1, characterized in that: The circuit production step uses laser cutting to form a circuit pattern.

10. The method for making an ultra-thick copper-gold plate according to claim 1, characterized in that: The adhesive layer is a polypropylene adhesive layer.

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